Abstracts of AOCNMB and SNMICON 2025

ABAOCNMB042: Cyclotron production, radiochemical separation and radiolabeling of functionalized platinum nanoparticles with alpha-emitter ²¹¹At

Sanchita Ghosh,^1,2 Debashis Banerjee,^2,3 and Rubel Chakravarty^1,2,*

¹Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India, ²Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India, ³Radiochemistry Division (BARC), Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata, 700064, India

Introduction

Targeted alpha therapy (TAT) is now emerging in advanced cancer management due to the short range and high linear energy transfer (LET) of α-particles [1]. Astatine-211 has attained significant interest for TAT over other α-emitters as it emits only one α-particle per decay which alleviates certain concerns related to in vivo administration and also simplifies dosimetry calculations. In this study, we have produced ²¹¹At via ²⁰⁹Bi (α, 2n) ²¹¹At reaction in a cyclotron and radiochemically separated it for formulation of a nanoradiopharmaceutical.

Materials and Methods

Natural Bi₂O₃ target in pelletized form wrapped in Al foil (foil thickness ~25.4 µm) was irradiated with 30 MeV α-beam in the K-130 cyclotron at VECC, Kolkata. The irradiated target was first cooled down and dissolved in 2 M HNO₃ at room temperature. Subsequently, Bi was precipitated as Bi(OH)₃ using 2 M NaOH followed by the separation of ionic sodium astatide solution by centrifugation and membrane filtration. The radiochemically separated ²¹¹At was used for labeling gum arabic functionalized platinum nanoparticles (Pt-GA NPs) by surface adsorption. The radiochemical stability of [²¹¹At]Pt@GA NPs was evaluated under physiological conditions. Moreover, photothermal heat conversion capability of Pt@GA NPs was also explored by illuminating the NPs with 808 nm laser.

Results

The batch yield of ²¹¹At at the end of irradiation was ~ 6.0 ± 0.3 MBq.µA^-1.h^-1. The overall separation yield of ²¹¹At was ∼ 80% with >99.9 % radionuclidic purity. The γ-spectra of the decayed samples did not show presence of extraneous radioisotopes. Graphite furnace atomic absorption spectrometry (GFAAS) analysis of the decayed samples confirmed that the bismuth level was < 1 ppm in the radiochemically separated samples. Pt@GA NPs was radiolabeled with ²¹¹At adopting a non-covalent approach. The radiolabeling yield was found to be > 99 % and the radiolabeled nanoparticles retained their integrity under physiological conditions over a period of 21 h. On the other hand, Pt@GA NPs also showed good photothermal conversion efficiency as the temperature of the NPs reached up to 43 ^oC after 6 min of irradiation, demonstrating the potential of this nanoagent for dual modality (radiation/photothermal) therapy.

Conclusion

The current strategy simplifies the production of ²¹¹At by simplifying the purification process, potentially making this radioisotope more accessible and cost-effective for cancer treatment. Furthermore, [²¹¹At]Pt@GA NPs offer promising potential for dual-modal radio-photothermal therapy.

ABAOCNMB043: Utility of Radiation Survey in High-Dose Radionuclide Therapy Ward for Minimising Non-Therapeutic Radiation Exposure to Thyroid Cancer Patients Admitted for Iodine-131 High-Dose Radioiodine Therapy

Kurra Bindusagar, Teckchand Kalawat, Rallapeta Ramya Priya, Parthasarathi Ravi

Asian Institute of Gastroenterology

Introduction

Radioiodine (I-131) high-dose therapy is a standard treatment for differentiated thyroid cancer patients. However, residual contamination in therapy wards after patient discharge may pose unnecessary radiation risks to healthcare personnel and subsequent patients.

Aim

The aim of this study was to conduct a radiation survey in the high-dose therapy ward following patient discharge to identify potential contamination sites and implement corrective actions.

Materials and Methods

This prospective study was conducted in the High-Dose Radioiodine Therapy Ward, Department of Nuclear Medicine. After the discharge of patients treated with Iodine-131, each isolation room was surveyed using a handheld radiation survey meter—Geiger-Müller tube type (RAM GAM 1 RUGG, Model: BAK-1750). Measurements were taken from various surfaces in microsieverts per hour (μSv/h) to identify potential contamination zones. Based on the survey findings, corrective measures were implemented to limit the spread of contamination and minimise non-therapeutic radiation exposure to both healthcare workers and future patients.

Results

The highest levels of contamination were observed on pillow covers, likely due to patient perspiration, salivation, and respiratory secretions (sneezing/coughing). The next highest contamination was found on the sink surfaces, followed by the floor area in front of the washroom, and the bed surfaces. All other surveyed areas recorded readings within permissible safety limits. The data highlights specific zones within the ward that require enhanced cleaning protocols.

Conclusion and References

Radiation contamination surveys in therapy wards post-discharge are essential for maintaining a safe clinical environment. This study successfully identified high-risk surfaces for residual Iodine-131 contamination. However, recognising these frequent contamination zones enabled the implementation of targeted precautions to further reduce the risk of unnecessary radiation exposure. These findings support ongoing quality assurance in nuclear medicine facilities and reinforce the importance of routine radiation monitoring.

ABAOCNMB045: Investigation of the therapeutic efficacy of [¹⁷⁷Lu]Lu-labeled-Cetuximab-photosensitizer conjugate: Exploring the potential of combination therapy

Samrudhi Kar^1,2, Aneena R³., Mohini Guleria^1,2, Tapas Das^1,2

¹Homi Bhabha National Institute, Anushaktinagar, Mumbai - 400094, India, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai - 400085, India ³PSGR Krishnammal College for Women, Coimbatore

Introduction

Cetuximab is an FDA approved monoclonal antibody for immunotherapy of metastatic colorectal cancer as well as head and neck squamous cell carcinoma. However, its therapeutic effect is limited, and there is a need to develop new approaches to improve its efficacy.

Aim

In the present work, an attempt was made to synthesize [¹⁷⁷Lu]Lu-labeled-Cetuximab-porphyrin conjugate (porphyrin as a photosensitizer) to evaluate its potential towards cancer treatment using a dual modality approach. The modalities used in this work for accomplishing the goal of combination therapy are PDT (photodynamic therapy) and radionuclidic therapy.

Materials and Methods

Cetuximab was conjugated with porphyrin followed by purification using a PD-10 column. Porphyrin loading and protein estimation studies with purified conjugate were performed using UV-Vis spectrophotometry. Fluorescence cell imaging was carried out to assess the cellular internalization of Cetuximab-porphyrin conjugate in A431 cancer cells (EGFR overexpressing skin carcinoma cell line). The cytotoxicity of the antibody-porphyrin conjugate was evaluated using an MTT assay. Cetuximab-porphyrin conjugate was also radiolabeled with ¹⁷⁷Lu, a well-established therapeutic radionuclide. For this, DOTA, a bi-functional chelating agent (BFCA), was conjugated with Cetuximab-porphyrin conjugate, purified and radiolabeled with ¹⁷⁷Lu. The radiochemical purity (RCP) of the radiolabeled complex was assessed using paper chromatography (radio-TLC) and radio-HPLC equipped with size exclusion column. To test the efficacy of the combination therapy (combined effect of photocytotoxicity and radionuclidic therapy), a clonogenic assay was performed in A431 cells followed by evaluation of therapeutic efficacy of [¹⁷⁷Lu]Lu-labeled-DOTA-Cetuximab-porphyrin in EGFR positive tumor bearing NUDE mice.

Results

UV-Visible spectrophotometric analyses revealed that about ~2 porphyrin molecules were attached per Cetuximab and ~3 DOTA molecules per Cetuximab-porphyrin conjugate. Fluorescence cell imaging studies showed better intracellular penetration of porphyrin after conjugation with Cetuximab. Cytotoxicity assay showed minimal toxicity in the dark, while prominent cell death was seen under light exposure. Post radiolabeling with ¹⁷⁷Lu, [¹⁷⁷Lu]Lu-labeled-DOTA-Cetuximab-porphyrin complex was prepared with a final radiochemical purity >98 %. Clonogenic assay showed significant enhancement in cell death under light exposure. In-vivo imaging studies in NUDE mice showed high uptake in tumor mass at 4 days post-administration. Therapeutic efficacy studies showed a clear reduction in relative tumor volume in the combination therapy group compared to control.

Conclusion

The present work investigates the combined effect of photodynamic therapy and radionuclidic therapy to enhance the targeted therapy of cancer. [¹⁷⁷Lu]Lu-labeled-DOTA-Cetuximab-porphyrin complex showed significant therapeutic effect in combination with PDT in both in-vitro and in-vivo studies.

ABAOCNMB059: Retrospective Analysis and Optimization of Automated Fluorine-18 Radiopharmaceutical Production Across Two Synthesis Platforms

Raviteja Nanabala¹, Arun PK¹, Junais Pokkat¹, Anees Muhammed K¹, Dilshad Kottuparamban¹, Shinooj Maniyoth Kuni¹, Vishnunath Pazhakkal¹, Thomas George¹, Sudhakaran Nair K¹, Ajith K Joy¹, Maroor Raghavan Ambikalamajan Pillai¹

¹Molecular Cyclotrons Pvt. Ltd., Puthuvype, Ernakulam, 682508, Kerala, India

Introduction

[¹⁸F]FDG remains the gold-standard PET tracer for cancer diagnosis and treatment planning; however, its limited specificity for certain cancers and high brain uptake due to glucose metabolism can hinder disease detection. Alternative tracers such as [¹⁸F]FDOPA, [¹⁸F]FET, [¹⁸F]FCholine,[¹⁸F]FMISO and [¹⁸F]FPSMA-1007 are increasingly used for specific indications. Despite their clinical importance, production frequently suffers from low radiochemical yields and batch inconsistencies in automated synthesis modules, thereby creating inconvenience to the patients undergoing PET-CT [1]. With limited literature addressing optimization and troubleshooting, we retrospectively analysed production runs of multiple ¹⁸F-radiopharmaceuticals using different modules at our facility to identify performance gaps and implement troubleshooting strategies.

Materials and Methods

[¹⁸F]Fluoride was produced using an 11 MeV Siemens Eclipse HP cyclotron. [¹⁸F]FDOPA and [¹⁸F]FCholine cassettes were procured from ABX and Trasis (Belgium), while [¹⁸F]PSMA-1007 and [¹⁸F]FET cassettes and precursors were sourced from ABX (Germany). A retrospective analysis was performed focusing on decay-corrected radiochemical yields, batch-to-batch consistency, and failure rates across Trasis and Neptis modules. Troubleshooting strategies included synthesis software updates, module performance checks, and procedural refinements.

Results

Decay-corrected yields were: 51 ± 8.2% (n = 29, Trasis) versus 10.2 ± 2.3% (n = 33, Neptis) for [¹⁸F]FDOPA; 32 ± 1.3% (n = 9, Trasis) versus 18.3 ± 6.1% (n = 42, Neptis) for [¹⁸F]FCholine; 49.4 ± 17.6% (n = 8, Neptis) and 50 ± 5.4% (n = 2, Neptis) for [¹⁸F]FET. Trasis outperformed Neptis for [¹⁸F]FDOPA and [¹⁸F]FCholine production in both yield and consistency. Troubleshooting reduced [¹⁸F]FDOPA failures on Trasis from 50% to 0% by updating the synthesis sequence. [¹⁸F]FCholine failures on Neptis decreased from 5% to 2% by including a step-in cassette preparation; the 2% represented a single human-error–related failure, after which no further failures occurred. No production failures were observed for [¹⁸F]PSMA and [¹⁸F]FET using Neptis. All tracers achieved radiochemical purity >96% and stable for 10 hours with all QC parameters within pharmacopeial limits.

Conclusion

This study demonstrates that systematic retrospective analysis and targeted troubleshooting can markedly improve the reliability of ¹⁸F-radiopharmaceutical production. To our knowledge, this is among the first reports quantitatively comparing multiple ¹⁸F-tracers across two automated synthesis platforms while also documenting effective corrective measures. These optimizations enhanced tracer availability, minimized production downtime, and ensured timely patient care, offering a practical model for other facilities facing similar production challenges

ABAOCNMB060: Operational Experience of Bulk Iodine-131 Dispensing in a Private GMP Facility: First Report from India

Hridya Raj R¹, Anjana Gopa1¹, Anuja T R¹, Sruthi Mol S¹, Akshara L Sunil¹, Raviteja Nanabala^1,2, Sudhakaran Nair K^1,2, Ajith K Joy,^1,2, Maroor Raghavan Ambikalamajan Pillai^1,2

¹Molecular Radionuclide Pharmacy Pvt Ltd., Puthuvype, Ernakulam, 682508, Kerala, India, ²Molecular Cyclotrons Pvt Ltd, Puthuvype, Ernakulam, 682508, Kerala, India

Introduction

Iodine-131 (I-131) is a therapeutic radioisotope widely used for the treatment of thyroid cancer. It is administered either in liquid or capsule form. Currently, due to limited indigenous production, multiple small consignments of I-131 are imported from abroad, adding to both cost and logistical challenges. Hence, bulk importing and local dispensing can address this gap to ensure uninterrupted supply to hospitals. Our previous work highlighted the establishment of a GMP-based I-131 facility (poster presented in SNMICON 2024). To the best of our knowledge, this is the first report from India where a private GMP-compliant facility shares its institutional experience of formulation, dispensing, and supply I-131 to hospitals.

Materials and Methods

Bulk I-131 was procured from NTP Radioisotopes (South Africa) and ROSATOM (Russia). Formulation was carried out using sodium hydroxide and sodium thiosulfate (Merck). For each batch, 10⁻⁴ M NaOH at pH 10 and ~25 mg/Ci sodium thiosulfate were used for the formulation. Radiochemical(RC) purity was assessed by paper chromatography as described in the Indian Pharmacopoeia, using the cut-and-measure method with a Geiger-Müller counter (Ludlum, USA). Radionuclide purity was confirmed with a multichannel analyser (Para Electronics, India). The hot cells were indigenously fabricated (Samriddhi, India), while automated liquid and capsule dispensing was performed using Elex Icaps (Serbia).

Results

A total of 14 batches of bulk I-131 were dispensed over seven months (Feb–Aug 2025), handling 165 Ci (6.105 TBq) of activity. The RC purity of the finished product was retained for 20 days, although bulk stock was usually consumed within two weeks of arrival. Overall, ~300 consignments were supplied to hospitals using AERB approved MRL 30 and MRL 20 transport packages.

Conclusion

This report represents a GMP-compliant I-131 dispensing facility sharing its operational experience. The hot cells and transport packages are indigenously developed and the operation were carried out with radiologic safety. The facility has enhanced the availability of I-131 in southern India thereby benefitting thyroid cancer patients.

ABAOCNMB066: Evaluation of Clinical Response and Toxicity Profile of Alpha Radionuclide therapy [²²⁵Ac-DOTATATE based Peptide Receptor Radionuclide Therapy (PRRT)] in patients with Resistant Metastatic Neuroendocrine Tumors (NETs) in a tertiary care setting.

^1,2Roopal Agrawal, ^1,2Rahul Parghane, ^1,2Sandip Basu.

¹Radiation Medicine Centre, BARC; ²Homi Bhabha National Institute, Mumbai.

Introduction and Aims

Over 60% of NETs present at an advanced stage, often with metastatic inoperable disease. Available treatments include surgery, medical therapies [somatostatin analogues (SSA), interferon alpha and targeted therapies], and PRRT targeting somatostatin receptors (SSTR). Alpha Radionuclide therapy has a potential role in progressive resistant cases, citing physical characteristics like high linear energy transfer and short-range of alpha particles.

We aimed to evaluate the therapeutic response, progression free survival (PFS), overall survival (OS) and clinical toxicity of Alpha Radionuclide Therapy (²²⁵Ac-DOTATATE based PRRT) in patients with Metastatic NETs with disease progression on ¹⁷⁷Lu-DOTATATE PRRT.

Materials and Methods

This was a single institutional, prospective observational study from 2021 to 2024. The study population consisted of 16 patients with Metastatic NETs with disease progression on ¹⁷⁷Lu-DOTATATE PRRT, who received ²²⁵Ac-DOTATATE based PRRT.

Response to treatment was evaluated under 3 categories:

(a) Symptomatic (b) Biochemical (Serum Chromogranin A levels) and

(c) Imaging response (RECIST 1.1 for anatomical imaging and PERCIST 1.0 for molecular imaging).

The PFS and OS were determined following treatments. Acute toxicity (nausea, vomiting, pain, diarrhoea, and hormonal crisis) and chronic toxicity (hemato-toxicity, hepato-toxicity and nephro-toxicity) was assessed in all patients by NCI-CTCAE scale version 5.0.

Results

A total of 16 patients with Progressive Metastatic NETs were included and analysed in the study. There was a significant improvement in functional and pain-related symptoms in 40% patients, with biochemical partial response observed in 60% patients post-therapy. The disease control rate was calculated to be 66.6% on anatomical imaging. No significant acute toxicities were reported, with less than 10% of the patients exhibiting grade II or worse chronic toxicities.

The follow-up period after the 1^st cycle of ²²⁵Ac -DOTATATE therapy ranged from 1.4 months to 44 months. The average PFS and OS were calculated to be 13.2 and 16.5 months respectively at the time of censorship.

Conclusion

We concluded that patients with progressive metastatic NETs, who were treated with targeted alpha therapy showed significant clinical, biochemical and anatomical response, with minimal adverse effects, making it a promising therapeutic option in this subgroup of patients with resistance to multiple lines of treatments

ABAOCNMB065: Evaluation and comparison of Clinical Response and Toxicity profile of Alpha Radioligand therapy (RLT) (²²⁵Ac-PSMA-617) vs Salvage Beta RLT (¹⁷⁷Lu-PSMA-617) & Chemotherapy in Progressive Metastatic Castration Resistant Prostate Cancers (mCRPC)

Roopal Agrawal, Rahul Parghane, Sandip Basu.

HBNI, Radiation Medicine Centre, BARC, HBNI Mumbai.

Introduction and Aims

The conventional treatment for mCRPC includes androgen deprivation, taxane chemotherapy, immunotherapy, PARP inhibitors, and radionuclide therapy. However, resistance remains common due to tumour adaptations, with limited options for patients with progressive mCRPC. We aimed to compare the therapeutic response, progression free survival (PFS), overall survival (OS) and clinical toxicity of Alpha Radionuclide Ligand Therapy (RLT) (²²⁵Ac-PSMA-617) vs salvage beta-RLT (¹⁷⁷Lu-PSMA-617) vs chemotherapy (taxanes or cyclophosphosphamide) in patients of progressive mCRPC.

Materials and Methods

This was a single institutional, prospective observational study from 2021 to 2024. Patients with progressive mCRPC were categorized into 3 groups (baseline characteristics balanced between groups) based on treatment undertaken, depending upon the availability of isotopes, patient choice and financial constraints, i.e, either ²²⁵Ac-PSMA-617 based RLT (group A), salvage ¹⁷⁷Lu-PSMA-617 based RLT (group B) or chemotherapy with taxanes or cyclophosphosphamide (group C).

Response to these treatments were evaluated after 6 months of treatment initiation under 3 categories:

(a) Symptomatic (b) Biochemical [serum Prostate Specific Antigen (PSA)] and

(c) Imaging response (RECIST 1.1 for anatomical imaging and PERCIST 1.0 for molecular imaging).

The PFS and OS were determined following treatments. Acute and chronic toxicity was assessed in all patients by NCI-CTCAE scale version 5.0 for hemato-toxicity, hepato-toxicity, nephro-toxicity, and salivary gland toxicity.

Results

A total of 30 patients (10 in each group) with progressive mCRPC were included and analysed in the study. The follow-up period after the initiation of treatments ranged from 1.4 to 13 months. Group A patients (²²⁵Ac-PSMA-617) showed the greatest disease control rate of 75% on anatomical imaging, as compared to 40% in group B and 40% in group C. Biochemical partial response was noted in 60% patients in group A; 30% patients in group B and 40% patients in group C.

No significant drug related adverse events were reported in the A and B group, whilst 20% of the patient’s undertaking chemotherapy developed grade II or worse toxicities. However, significant salivary gland toxicity was noted in 100% patients in group A and 40% patients in group B.

The median overall survival was 9.2 months in group A, 4.1 months in group B and 5 months in group C.

Conclusion

We concluded that patients treated with targeted alpha therapy showed better response than the other two subgroups, even after disease progression on existing standard of care therapies. However, the isotope availability and affordability remain a challenge in this country.

ABAOCNMB068: Optimized Single Time Point Dosimetry For Renal Dose Estimation in LU177 PRRT Using Hanschied Approximation

Valaiyapathy N C, INDIRANI M, SHELLEY SIMON

Apollo Hospitals

Introduction

Peptide receptor radionuclide therapy (PRRT) using Lutetium-177 (Lu-177) labeled agents is widely employed for treating neuroendocrine neoplasms expressing somatostatin receptors (SSTR). Accurate renal dosimetry is essential to prevent nephrotoxicity, a key limiting factor in therapy. Traditional dosimetry protocols require multiple post-therapy imaging time points, posing logistical challenges. This study aims to evaluate the efficacy of a single time-point imaging method for assessing renal radiation dose after Lu-177 PRRT.

Materials and Methods

Patients undergoing Lu-177 PRRT were prospectively recruited for renal dosimetry assessment. Renal uptake was measured using Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) imaging in Medium Energy General Purpose Collimator, with 15% energy windowing at 208 KeV at multiple time points post Lu-177 PRRT. Time Activity Curve for renal dose with SPECT CT image was developed using Hanschied approximation (1) for single time point assessment at 36 hours. Multiple time point dosimetry was calculated in available patients. Renal absorbed dose averaged over both kidneys were calculated.

Results

Total of 30 cycles of Lu177 PRRT in 12 patients were included in the study. Post therapy SPECT CT images were acquired in 36 hours for all the patients, while additional scans at 12 and 60 hours were acquired in 12 patients. Mean renal absorbed dose using single time point assessment was 2.1 Gy (Range – 1.45 – 3.8). The mean Renal absorbed dose was 2.65 Gy at first cycle and 2.93 Gy at second cycle. Renal absorbed dose in the same patients at multiple time point assessment was 3.62 Gy. There was statistical significant difference in the renal absorbed dose at single time point assessment at 36 hours and multiple time point Dosimetry.

Conclusion

Single time-point renal dosimetry after Lu-177 PRRT is a feasible and reliable alternative to traditional multi time-point methods. This streamlined approach can facilitate wider implementation of personalized dosimetry in clinical practice, improving patient convenience while ensuring renal safety in PRRT protocols.

ABAOCNMB069: Expanding the role of targeted radionuclide therapy: Early results of Terbium-161 therapy in India with emphasis on hematological toxicity

Dinesh Kumar Gauthaman, Indirani Muthukrishnan, Shelley Simon

Department of Nuclear Medicine, Apollo Hospitals, Chennai

Introduction

Terbium-161 (Tb-161) is an emerging therapeutic radionuclide with potentially improved tumoricidal efficacy compared with Lutetium-177 (Lu-177). Due to similar chemical properties of Lu-177 and Tb-161, the latter can also be radiolabeled with [DOTA°,Tyr³]octreotate (DOTATATE), prostate specific membrane antigen (PSMA) and fibroblast activation protein inhibitor (FAPI). The aim of this study is to evaluate the safety of Tb-161 therapy in treatment refractory metastatic cancers.

Materials and Methods

This prospective observational study includes 5 patients (4 males, 1 female; mean age 66.4 years) with metastatic, treatment-refractory malignancies including prostate carcinoma (3 patients), well differentiated grade 2 pancreatic neuroendocrine tumor (1 patient), and high-grade transitional cell urinary bladder carcinoma (1 patient), who received a total of 6 cycles of Tb-161 based radionuclide therapies. All the patients had progressive disease on conventional therapies, Eastern Cooperative Oncology Group performance status of 0-2, Gallium-68 based PET-CT positivity (maximum standardized uptake value ≥10), acceptable bone marrow, renal and liver function, and received Tb-161 therapy on compassionate grounds, after Institutional Ethical Committee clearance (AMH-003/02-2025). Patients received intravenous Tb-161–labelled radiopharmaceuticals (PSMA, DOTATATE, or FAPI; 110–150 mCi per cycle). Clinical, biochemical and imaging outcomes were recorded. Adverse events were defined by Common Terminology Criteria for Adverse Events version 5.0.

Results

A total of 6 cycles of Tb-161 therapy in 5 patients were uneventful and post-therapy imaging performed at 6–78 hours confirmed good tracer biodistribution and lesion targeting across all three radiopharmaceuticals. One patient with metastatic prostate cancer who underwent 2 cycles of Tb-161 PSMA therapy at 10-week interval had significant pain relief and stable disease in Gallium-68 PSMA PET-CT after his first cycle. His pain score reduced from 6/10 to 1/10 with reduction in intake of analgesics. Hematological toxicity was the predominant adverse effect. Grade 3 hematotoxicity was observed in 2 patients (nadir biochemical values at 4 weeks post therapy) who had received multiple lines of chemotherapy and radionuclide therapy prior, and recovered with packed red cell transfusions for anemia (prostate carcinoma) and Romiplostim (thrombopoietin receptor agonist) for thrombocytopenia (neuroendocrine tumor). No Grade 4 treatment related adverse events or treatment related deaths occurred (median follow up – 73 days).

Conclusion

Tb-161 therapy using PSMA, DOTATATE, and FAPI ligands is feasible and safe in progressive, metastatic carcinoma patients. Appearance of grade 3 hematotoxicity underscores the need for frequent biochemical monitoring. Larger randomized clinical trials are warranted to validate efficacy and establish its long-term safety.

ABAOCNMB079: To evaluate Fibroblast Activation Protein (FAP) expression in primary and metastatic breast cancer using ⁶⁸Ga-FAPI-04 PET/CT and compare it with the conventional Glucose transporter (GLUT) expression using ¹⁸F-FDG-PET/CT

Kavita Patil¹, Gaurav Malhotra¹, Shilpa Rao² and Sandip Basu¹.

¹Radiation Medicine Centre, Bhabha Atomic Research Centre & Homi Bhabha National Institute, Mumbai, India, ²Department of Surgery, Seth GS Medical College and KEM Hospital, Mumbai, India.

Introduction and Aim

⁶⁸Ga-FAPI PET/CT (FAPI) that targets fibroblast activation protein has a potential to overcome shortcomings of ¹⁸F-FDG PET/CT (FDG) in evaluation of breast cancer including both false positive (e.g. infections) and false negative (e.g. lobular carcinoma) scenarios. The aim of this study was to compare diagnostic performance of FAPI with FDG in detecting primary and metastatic lesions in breast cancer patients.

Methods

Twelve female patients (39-79 yrs age; median:52 yrs) of metastatic breast cancer, half of these being invasive ductal carcinoma and remaining half of no special type were included in the study. All patients underwent FAPI and FDG 1-2 week apart (median: 10 days) as per the institution protocol. Lesion-based analysis was conducted for primary tumors and metastatic sites to compare detection rates between the two scans. A positive finding on either scan was deemed true positive. Standardized uptake value (SUVmax) values (mean±SD) were compared between the two scans. Likewise, imaging performance of both the scans was compared between the triple negative breast cancer (TNBC) and non-TNBC molecular sub-types.

Results

In lesion-based analysis, FAPI demonstrated higher detection rate of 98.62% (143/145 lesions) as compared to FDG, which showed a detection rate of 84.3% (118/145 lesions) across all tumor sites. All primary breast tumors were detected with FAPI while 82.35% (14/17) were detected with FDG. Lymph node, lung and liver metastases showed 100% detection rate on FAPI while corresponding lesion detection rates for FDG were 71.73% (33/46), 81.25% (13/16) and 90.9% (10/11) respectively. Similarly, FAPI detected 96% (49/51) of bone metastases as compared to 86.27% (44/51) for FDG. 4 metastatic brain lesions showed 100% detection rates with both imaging modalities but FAPI offered better tumour to background ratio due to no physiological brain uptake. FAPI showed higher SUVmax (mean±S.D) of 11.7±7 as compared to 7.9±4.1 for FDG across all lesion sites (p value<0.05). Comparison of TNBC (56 lesions in 5 patients) and non-TNBC (89 lesions in 7 patients) for FAPI revealed SUVmax (mean±S.D) of 11.74±6.3 and 11.7±7.3 respectively (non-significant) while for FDG these values were 9.9±4.7 and 6.5±3.04 respectively (p value<0.001).

Conclusion

⁶⁸Ga FAPI PET/CT offers better diagnostic accuracy and sensitivity as compared to ¹⁸F-FDG PET/CT in detecting both primary and metastatic breast cancer lesions. Difference between TNBC and non-TNBC, SUVmax (mean±S.D) values of FAPI was not significant likely implying its potential utility in detecting low grade tumours, lesions with molecular heterogeneity and non-FDG concentrating tumours

ABAOCNMB085: Dual-Time FDG PET/CT Volumetry Meets Early Dynamic Behaviour: A Novel Hybrid Biomarker For Vascular Invasion and Poor Prognostic Features

Prakash Singh, Manish Ora, Vineet Mishra, Yogita Khandelwal, Krishna Kant

King George's Medical University

Introduction

Hepatocellular carcinoma (HCC) is frequently complicated by portal vein tumor thrombosis (PVTT), a hallmark of aggressive biology associated with poor prognosis. PET/CT has been increasingly investigated for its ability to provide both metabolic volumetry and kinetic behavior. While dual-time imaging captures delayed retention, early dynamic scans (0–5 minutes) can reflect vascular perfusion and metabolic wash-in. Integrating these two domains may uncover hidden aggressiveness and improve detection of macrovascular invasion.

Aims

This study aimed to quantify early-to-delayed volumetric drift in metabolic tumor volume (MTV) and total lesion glycolysis (TLG), assess whether early kinetic parameters (wash-in slope, retention indices) complement dual-time volumetric changes, and evaluate their diagnostic performance for PVTT detection and associations with poor prognostic features such as elevated alpha-fetoprotein (AFP), poor grade, multifocality, and extrahepatic spread.

Materials and Methods

We retrospectively analysed 25 consecutive patients with HCC who underwent dynamic liver-bed PET (0–5 min) followed by whole-body PET/CT at 60 min. The reference standard for PVTT was established by imaging, surgery, or multidisciplinary consensus within 30 days. MTV and TLG were measured at 5 and 60 min to calculate ΔMTV% and ΔTLG%. Early kinetic indices, including wash-in slope and lesion-to-blood uptake product (ΔLBUP 0–5), were derived from dynamic scans. Retention index (RI%) was calculated from SUV max at5- and 60-min. Statistical analyses included Mann–Whitney U tests, Spearman correlations, logistic regression modelling, and ROC curve analysis with bootstrap validation.

Results

PVTT was present in 20% of patients and was associated with significantly higher wash-in slopes, ΔTLG%, and RI% compared to PVTT-negative cases (p = 0.001, 0.013). Early kinetics correlated moderately with volumetric drift and AFP levels, indicating complementary domains of tumor behaviour. Univariable analysis confirmed each marker’s discriminatory value, while multivariable logistic regression integrating wash-in slope and RI% yielded superior diagnostic accuracy. The integrated model achieved an AUC >0.85, outperforming single-domain models (p<0.05). Secondary analyses showed strong associations between ΔTLG% and AFP ≥400 ng/mL, consistent with aggressive biology.

Conclusion

Dual-time volumetry and early dynamic kinetics provide complementary insights into HCC biology. Early wash-in slope and delayed retention act synergistically, improving non-invasive detection of PVTT and correlating with poor prognostic features. This hybrid PET/CT biomarker strategy has potential clinical utility in refining risk stratification and treatment planning for HCC.

ABAOCNMB096: Quantification of Myocardial Gallium-68 FAPI Uptake in Coronary Artery Disease Patients and Its Prognostic Value

Anusha Raju, Indirani M, Shelley S

Apollo Hospitals Chennai

Introduction

Coronary artery disease (CAD), caused by plaque buildup in coronary arteries, is the leading cause of heart failure globally. It involves complex reparative and reactive fibrotic processes. 68-Ga FAPI PET imaging, a novel molecular tool, targets activated fibroblasts central to fibrosis. Unlike conventional modalities, it enables direct visualization and quantification of fibroblast activity, offering molecular insights into tissue remodelling and prognosis in CAD. Early studies show strong correlations between 68-Ga FAPI uptake and myocardial injury markers like NT-proBNP, high-sensitivity troponin, and left ventricular ejection fraction (LVEF). Moreover, higher FAPI uptake links to disease severity and adverse cardiovascular outcomes, highlighting its prognostic potential.

Aim

To assess the myocardial uptake of 68-Ga FAPI in CAD patients quantitatively and investigate its relationship with clinical parameters and potential value in predicting adverse cardiac outcomes.

Materials and Methods

This prospective observational study, conducted at our tertiary care centre from November 2023 to August 2025, included 30 patients with CAD referred by cardiologists. Clinical characteristics, laboratory results, imaging findings and management details were reviewed. Quantitative assessment involved calculating standard uptake values (SUV) in ischemic, infarcted, and remote myocardial regions. Data on LVEF, prior myocardial infarction and NT-proBNP levels were collected where available and patients were followed up. A three-day imaging protocol was followed; which included rest myocardial perfusion SPECT/CT, 18-F FDG PET/CT and 68-Ga FAPI PET/CT. Following 122–336 MBq of 68-Ga FAPI injection, cardiac scan was done at 45–60 minutes and visual and quantitative interpretation was done.

Results

This study enrolled 30 patients (26 males, 4 females; median age 61 years) with 63.3% having prior percutaneous transluminal coronary angioplasty or coronary artery bypass graft. The mean left ventricular ejection fraction (LVEF) was 36.8%, and global longitudinal strain (GLS) averaged 6.5. Mean SUVmax values were 5.0 in scarred myocardium, 3.7 in hibernating myocardium, and 3.8 in normally perfused myocardium at risk of remodelling. Patients lacking 68Ga-FAPI uptake in scarred myocardium experienced more adverse events and demonstrated greater uptake in at-risk myocardium. Uptake extent increased with worsening GLS in both scarred and at-risk regions.

Conclusion

Quantification of myocardial 68-Ga FAPI uptake offers a promising non-invasive biomarker for detecting active fibroblast-mediated remodelling in CAD patients. Its uptake pattern correlates with clinical markers of disease severity and may provide prognostic information to guide risk stratification and personalized management strategies.

ABAOCNMB098: A Practical Comparison of Lu-177 Administration Methods : Syringe Pump vs Infusion Pump

Anumanthini G, Shelley Simon

Apollo Hospitals

Introduction

Lutetium-177 (Lu-177) therapy is an increasingly utilized radionuclide therapy for treating neuroendocrine tumors and metastatic prostate cancer. The method of radiopharmaceutical administration plays a critical role in determining the accuracy of delivered dose, radiation safety, and procedural efficiency. Common administration techniques include the syringe pump and infusion pump methods. The accuracy and consistency of Lu-177 administration are vital for ensuring optimal therapeutic efficacy, minimizing radiation exposure, and reducing radiopharmaceutical waste. Each technique presents unique advantages and limitations in terms of flow control, radiation safety, and ease of use.

Aim

To compare the syringe pump and infusion pump methods for Lu-177 therapy administration in terms of dose accuracy, radiation safety to staff, workflow efficiency, and practical feasibility in a nuclear medicine therapy setting.

Materials and Methods

A prospective observational study was conducted over 20 Lu-177 therapy sessions at our nuclear medicine department. Ten patients each were administered Lu-177 via syringe pump and infusion pump respectively. For each method, we recorded: (a) pre- and post-administration activity to calculate actual dose delivered and residuals, (b) radiation exposure to staff using calibrated electronic pocket dosimeters, (c) total administration time, and (d) qualitative feedback from technologists on ease of use, setup time, and risk of extravasation. Standard operating procedures and radiation protection protocols were followed throughout.

Results and Conclusion

The syringe pump method showed the highest dose accuracy, with residual activity < 2 %, but involved the longest setup and monitoring time. It also recorded lowest radiation exposure to staff due to closed-system operation. The Infusion pump method though cost-effective and simple, showed higher variability in dose delivery (residuals up to <0.5 %) and required frequent manual adjustments.

From a technologist’s perspective, the syringe pump is preferred when priorities staff training and standardization of procedures remain essential regardless of the method used.

ABAOCNMB103: Comprehensive Evaluation of Occupational Exposure to Drivers During Transport of ¹⁸F Radiopharmaceuticals in Type A Packages

Muhammed Anees. K ¹, Dilshad Kottuparamban¹, KN Sudhakaran Nair¹, MRA Pillai ¹, ADP Rao²

¹Molecular Cyclotrons Pvt. Ltd., Puthuvype, Ernakulam, 682508, Kerala, India, ² Department of Nuclear physics, Andhra University, Visakhapatnam, India

Introduction

Safe transportation of radiopharmaceuticals such as ¹⁸F-FDG is an essential aspect of nuclear medicine industry. The current practice is to consider drivers as public with exposure limit of 1 mSv per annum and they are not under dosimetry surveillance. However, it is important to evaluate the radiation dose received by drivers while transporting radiopharmaceuticals to ensure that the limit of 1 mSv per year set for public is not exceeded. The present study was undertaken to estimate the radiation dose received by drivers while transporting ¹⁸F radiopharmaceuticals in Type-A packages.

Materials and Methods

This study evaluated occupational exposure to drivers while transporting ¹⁸F radiopharmaceuticals in a sub four-meter sedan car. The drivers included in this study were registered as radiation workers and TLD batches were provided to them. In addition, a calibrated silicon semiconductor detector-based pocket dosimeters were provided to the drivers while carrying the packages.

Prior to departure, radiation surveys were performed using a calibrated GM based survey meter to measure dose rates around the vehicle, including all four side and the driver’s seating area. Surface dose rates of Type A radiopharmaceutical packages were also recorded, and the cumulative transport index (TI) was verified to remain below the limit of 50 while carrying multiple packages as per regulation. In order to reduce the radiation dose, a 12 mm lead barrier (1 TVL) was installed in the vehicle boot between the packages and the backside seats. The dosimeter reading obtained were consolidated and analysed w.r.t to the activity transported, time taken for transport as well as the distance. The dose recorded in TLD badges were also collected to compare with the dose recorded as per pocket dosimeter.

Results

The distance travelled varied from 20-220 km and the travel time varied from 40-300 min. Pocket dosimeter driver exposures were less than 50 µSv per trip when transported in vehicles which were not provided with extra shielding. While transporting with additional shielding, the dose recorded were lower by a factor of ~10 as we used lead equivalent to 1 TVL. Preliminary results suggest that drivers can be treated as public provided the number sorties are limited and also alternating the drivers for short and long trips. However, it could be good practice to keep the permanent drivers under TLD surveillance as is practiced by us.

Conclusion

This is a first comprehensive assessment of radiation exposure received during the transport of fluorine-18 radiopharmaceuticals. Preliminary results suggest that it is wise to keep the drivers carrying radioactive packages to long distances on a regular basis are kept under TLD surveillance. This will also enhance the confidence of the drivers regarding their radiation safety.

ABAOCNMB109: Good Manufacturing Practices for Hospital based Radio-pharmacy: Current Perspective and Regulations

Alok Kumar Rai, Manish Dixit and P. K Pradhan

Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow

Good Manufacturing Practices (GMPs) began to develop in the 1970s to prevent new pharmaceutical disasters, such as the use of poorly investigated toxic solvents (1930s). The GMP was developed as one of the tools to strengthen the quality of drugs for clinical applications. In 1950–1980, radiopharmacy also emerged adopting this concept as quality tool.

Radiopharmaceuticals are indispensable agents in modern medicine, serving critical roles in both diagnostic imaging and targeted therapeutic interventions. A significant advantage of radiopharmaceuticals is that they typically do not contain high doses of active pharmaceutical ingredients, thereby reducing the risk of adverse events associated with pharmaceutical/therapeutic doses that may have potential toxic properties. Their unique characteristics, however, pose significant challenges for manufacturing and quality control when compared to conventional pharmaceutical products.

Good Manufacturing Practice (GMP) is the bedrock for ensuring the safety, quality and efficacy of all pharmaceutical products. For radiopharmaceuticals, the fundamental objective of GMP remains consistent to ensure that the products are consistently produced and controlled to meet the quality standards appropriate for their future use. This objective is complicated by the addition of radioactivity, which attracts additional considerations related to radiation safety and the specialised handling of radio isotopes throughout the production process. The application of GMP in hospital radiopharmacies requires substantial adaptations and interpretation of standard pharmaceutical manufacturing guidelines.

Several guidelines were documented for adopting the GMP standards for in house radiopharmacies. These guidelines will help us to serve the patinets with good quality products in compliance with radiation safety too.

ABAOCNMB115: Excel based computations for Safety Assessment Report, a Recent Requirement in eLORA

Manisha Pradhan¹, Purshottam Singh², Binay Kumar Gupta^2, Abhishek Kumar², Gopal Sonai Muthu¹

¹Meherbai Tata Memorial Hospital, Jamshedpur, ²Tata Main Hospital, Jamshedpur

Introductions

According to a recent circular in the eLORA of AERB released in May 2025, all Nuclear Medicine institutions need to submit the Safety Assessment Report (SAR) and Radiation Protection Plan (RPP) at the time of obtaining Licence/Renewal of Licence to operate the equipment. Assessment of dose in normal operating conditions is required in the preparation of SAR to ensure that dose received by the Nuclear Medicine staff is within the acceptable limit.

Aim

To develop a user-friendly, MicroSoft Excel-based computational tool that automates the dose assessment in normal working conditions. This dose assessment is required to ensure that the total dose likely to be received by staff from all the routine Nuclear Medicine procedures is below the permissible limit of 400 μSv per week.

Materials and Methods

Dose rate has been measured at places wherever possible by using a survey meter with valid calibration. In situations where dose rates are not available, theoretical values were computed with following parameters: gamma Ray constant in mSv/hr/MBq, Half Value Thickness in mm, activity in MBq and distance in metres. The maximum dose receivable is calculated in the excel sheet by multiplying gamma ray constant, activity, attenuation correction factor and the distance correction factor. This calculation has been done for all procedures in the normal working condition such as preparation of radiopharmaceuticals, dispensing, dose administration, patient positioning, imaging and therapy. This calculation is also done for all the radionuclides used in the department and the total weekly dose received is computed in the last column of the excel sheet. Adding the dose received in the last column of the excel sheet gives the maximum dose receivable in one week.

Results

Maximum dose calculated from excel sheet for all the routine procedures in our hospital was 99 μSv per week that is far below the acceptable limit.

Conclusion

The computation of dose assessment for all the procedures during normal working condition is made easier by using excel sheet and can be used directly in the preparation of Safety Assessment Report that needs to be uploaded in eLORA while applying for new/renewal of Licence to operate.

ABAOCNMB116: Utility of cytogenetic biomarker evaluation in patients receiving therapeutic ¹⁷⁷Lu exposure.

Sushma Kaisar¹, Uma Bhartiya¹, Kamaldeep², Hritika Waingankar³, Smita Gawandi¹, N S Baghel¹, S. Basu¹.

¹Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India, ²Health Physics Division, Bhabha Atomic Research Centre, Mumbai, Indiam, ³D Y Patil School of Biosciences and Biotechnology, D. Y. Patil Deemed to be University, Navi Mumbai, India.

¹⁷⁷Lu based peptide radioreceptor therapy (PRRT) is widely employed in the management of neuroendocrine tumors (NETs) and prostate cancer. While offering selective tumor targeting, systemic exposure to internal radiation from ¹⁷⁷Lu can potentially result in off-target genotoxicity to other tissues. This study aims to assess radiation-induced DNA damage in peripheral blood lymphocytes (PBLs) of cancer patients receiving a single therapeutic IV dose of ¹⁷⁷Lu (6.03–7.96 GBq) with a combination of cytogenetic biomarkers.

Material and Method

Blood samples were collected from two groups: healthy volunteers (n = 6; control group) and prostate cancer patients and neuroendocrine tumors (n = 6). For the patient group, samples were taken both before and 72 hrs after the administration of ¹⁷⁷Lu therapy. Radiation exposure levels were monitored using a radiation survey meter at multiple time points during isolation, at the time of discharge and one-week post-therapy. To estimate whole-body radioactivity retention, the OLINDA/EXM software (version 2.2.1) was utilized, enabling quantitative assessment based on the measured exposure data. Further, cytogenetic markers of patients were also analyzed pre and post therapy condition.

Result

The Cytogenetic analyses included the cytokinesis-block micronucleus (CBMN) assay to quantify micronuclei (MN), nucleoplasmic bridges (NBR), and nuclear buds (NBUDs) in binucleated PBLs, along with evaluation of pseudo-Pelger-Huet anomalies in neutrophils. Pre therapy patients exhibited significantly higher PBL MN frequency compared to controls (p= 0.0126) and a statistically significant elevation in NBR frequency (p = 0.0454). A statistically significant increase in MN and NBR (p = 0.0257) was observed 72 hrs post¹⁷⁷Lu therapy exposure as compared to their Pre therapy status. The cumulative frequency of MN+NBR rose significantly after therapy (p = 0.024). However, the observed rise in individual MN and NBR frequency and cumulative frequency did not correlate with the administered radioactivity.

Conclusions

A combined assessment of cytogenetic biomarkers (PBL, MN frequency, NBR index) and pseudo-Pelger-Huet anomalies, alongside physical dosimetry, offers a robust dual-modality biodosimetry approach. This integrative strategy enhances radiation exposure assessment in ¹⁷⁷Lu PRRT patients and supports improved long-term monitoring and risk evaluation.

ABAOCNMB132: Integrated Delay Tank Radioactive Effluent Monitoring System for Multiple Tanks in a Nuclear Medicine Facility.

Pravind Maletha¹, Kamaldeep², Yuvraj Nitin¹, Sureshkumar MK², Baghel NS¹, Basu S¹.

¹Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India, ²Health Physics Division, Bhabha Atomic Research Centre, Mumbai, India.

Introduction

Delay tank systems play a critical role in the safe management of radioactive liquid effluents generated in radioiodine therapy ward in a nuclear medicine centre. These systems are designed to temporarily store and contain radioactive liquid effluents generated from radioiodine therapy wards, until their radioactivity decays to a level that are safe for discharge into the public sewage system. By incorporating multiple storage tanks operated in a sequential manner, delay tanks ensure adequate holding time for radioactive decay in accordance with national and international radioactive waste management regulations.

Safe handling and monitoring of liquid radioactive effluents in nuclear medicine facilities requires reliable tracking of activity and volume in delay tanks before discharge. Conventional systems often rely on isolated instruments, limiting remote accessibility and redundancy. This work presents the design and implementation of an integrated monitoring system that combines radiation, level, and visual monitoring of multiple delay tanks on a centralized platform.

This paper presents an overview of the design, operation, and regulatory framework of delay tank systems, with emphasis on their importance in minimizing environmental contamination and ensuring occupational and public safety.

Materials and Methods

a) Hardware & Software: The system integrates Ethernet-connected IP cameras, a Geiger-Muller detector-based radiation monitoring unit, and multiple 4–20 mA level sensors for redundancy. These inputs are processed through a Raspberry Pi, which serves as the central node for data aggregation, visualization, and control.

b) Method: Radiation counts, tank liquid levels, and live video feeds from two delay tanks are simultaneously transmitted over a LAN to the Raspberry Pi. The data is displayed in real time on a centralized dashboard, enabling remote monitoring. Built-in redundancy in the level sensors ensures reliability, while Ethernet connectivity allows secure multi-user access within the facility.

Results

The system demonstrated effective real-time monitoring of both delay tanks, providing stable radiation counts, consistent multi-sensor level data, and clear visual confirmation of tank conditions. Integration on a single Raspberry Pi platform simplified operations and improved situational awareness for operators.

Conclusion

This integrated delay tank monitoring system provides a cost-effective, scalable, and reliable solution for nuclear medicine facilities. By combining camera-based visualization, redundant level sensing, and radiation monitoring on a centralized Ethernet-connected platform, it enhances safety, operational efficiency, and regulatory compliance.

ABAOCNMB134: Enhanced Diagnostic Yield and Procedural Efficiency Using ARA-Assisted PET-CT Guided Biopsy

Naman Dhir, J Mohan Roop, Raghava Rao G, Avinash Bonda

AIG Hospitals, Gachibowli, Hyderabad

Objective

To evaluate the diagnostic success rate, procedural efficiency, radiation exposure, and complication profile of ARA-assisted PET-CT guided biopsies.

Introduction

Automatic robotic arm assisted (ARA) PET/CT guided biopsy is an innovative, image-guided interventional technique that integrates robotic precision with combined metabolic and anatomical imaging modalities. This enhances procedural reproducibility, reduces operator dependency, and improves biopsy accuracy in challenging anatomical locations.

Methodology

Patients fasted for 6 hours received an intravenous injection of 1–2 mCi of F-18 FDG.

Biopsy was scheduled 90-120 minute after injection, a limited PET/CT scan of the interested region performed to localize the lesion and assist in planning the biopsy trajectory. Standard sterile skin preparation and administration of local anesthesia conducted prior to image-guided needle insertion.

A check scan was performed immediately after needle placement, to confirm appropriate positioning within the target lesion, Tissue sampling was then performed and a post-procedure check scan was obtained to ensure successful biopsy.

A observational study was conducted involving 80 patients undergoing ARA-assisted PET-CT guided biopsies. Outcomes were compared to standard CT-guided biopsy data collected from interventional radiology department of our hospital. Parameters assessed included:

• Diagnostic success rates

• Procedural time (needle-in to needle-out)

• Number of check scans

• First sample success rate

• Sample adequacy

• Number of needle repositions

• Complication rates

• Radiation exposure to patient and physician

Results

• Diagnostic success rates were significantly higher in PET-CT guided biopsies:

  • Lung: 95.5%

  • Abdomen, Pelvis, Muscle: 100%

  Compared to 87% success rate for CT-guided biopsies

Challenging cases: 16 cases referred after prior unsuccessful image-guided biopsy attempts.

15 out of 16 patients (93.7%) with previous failed biopsies had diagnostic yield with PET-CT guidance.

• Procedural time reduced from an average of 42 minutes to 22–25 minutes.

• Radiation exposure was lower due to fewer check scans (2–3 in PET-CT vs 4–5 in CT-guided biopsy).

• First sample success rate improved from 60% to 80%.

• Overall sample adequacy for PET-CT was 80–90%, significantly higher than 20–30% with CT-guided biopsies.

• Needle repositioning was required in only 2 out of 80 cases, markedly lower than in CT-guided procedures.

• Complications:

  • Major (requiring hospitalization): None vs 2-5% for CT Guided biopsy

  • Minor: Observed in 2 patients (2.5%)—mild pneumothorax and hemoptysis, managed conservatively. Vs 10-15% for CT guided biopsy.

Abstract: When less than one means none: Stimulated thyroglobulin as a Safe Filter for follow-up Whole-body Iodine scan in Differentiated Thyroid Cancer

Hamid Althaf¹, Deepanksha Datta¹, Rajesh Kumar¹.

¹ Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, India.

Introduction

Differentiated thyroid cancer (DTC) generally carries an excellent prognosis. Follow-up strategies remain debated, particularly the role of follow-up I131 whole-body scans (FU-WBS) at 6–12 months. ATA guidelines suggest that patients with post-therapy stimulated thyroglobulin (sTg) <1 ng/mL and negative anti-Tg antibodies may not require routine FU-WBS. However, many centers continue the practice of FU-WBS. We conducted a retrospective audit at our tertiary institute (with a low-dose radioiodine therapy facility) to assess the incremental value of FU-WBS across different sTg values and ATA-risk groups, as well as radiation dose and outcome implications.

Materials and Methods

We included DTC patients who had undergone total thyroidectomy followed by radioiodine ablation, and assessed recurrence in those with at least 24 months of follow-up. Inclusion criteria were: negative anti-Tg, adequate stimulation (TSH >30 mIU/L), available sTg at 6–12 months, and FU-WBS. Actionable findings were defined as FU-WBS findings prompting repeat radioiodine therapy or management change. Radiation dose was estimated at 2–4 mSv per FU-WBS (after 2 mCi of I-131 intake).

Results

Fifty-four patients met criteria (36 with sTg <1 ng/mL, 11 with 1–10 ng/mL, 7 with >10 ng/mL).

Incremental yield: No patient with sTg <1 ng/mL had actionable FU-WBS findings; actionable yield 0.00% (95% CI 0.00–9.64), NPV 100% (90.4–100). Yield was 0.0% for 1–10 ng/mL and 28.6% (95% CI 8.2–64.1) for >10 ng/mL. No low- or intermediate-risk patients had actionable findings, whereas the two actionable findings occurred in high-risk patients with Tg ≥1 ng/mL.

Recurrence: Among 28 patients with ≥2 years’ follow-up (median 33 months, IQR 30–38), overall recurrence rate was 7.1% (2/28). None of the 17 patients with sTg <1 ng/mL had recurrence; recurrence occurred in 1/6 (16.7%) with 1–10 ng/mL and 1/5 (20.0%) with >10 ng/mL.

Radiation dose: Scanning all patients required 54 scans, detecting only two actionable findings, at a collective dose of ~108–216 mSv. A Tg-gated strategy (≥1 ng/mL) required 18 scans, detected the two actionable findings, and cut the dose to 36–72 mSv.

Conclusion

The sTg <1 ng/mL predicted absence of actionable FU-WBS findings and 2-year recurrence. Routine 6–12-month FU-WBS in this group appears unnecessary. A Tg-gated policy (FU-WBS when post-therapy sTg≥1 ng/mL) optimizes yield, reduces radiation dose, and aligns with risk-adapted ATA-guidelines-based follow-up.

ABAOCNMB154: Prospective Comparative Study of Intra-Arterial Versus Intra-Venous 177lU-Dotatate PRRT in Metastatic Or Locally Advanced Inoperable Gastroentero-Pancreatic Neuroendocrine Tumours

Rangat Bagasariya, Rahul Parghane, Nitin Shetty, Kunal Gala, Suyash Kulkarni, Sandip Basu

Radiation Medicine Centre, BARC

Introduction and Aims

¹⁷⁷Lu-DOTATATE PRRT has shown promising results in grade 1 & 2 gastroentero-pancreatic NETs. However, the patients with bulky inoperable hepatic metastases or locally advanced non metastatic NETs have poorer prognosis and treatment options become very limited if the disease does not respond to standard of care management. Here we propose ¹⁷⁷Lu-DOTATATE PRRT through intra-arterial route to maximise first pass extraction of the radiopharmaceutical by somatostatin receptors. The study aimed at assessing response and clinical toxicity evaluation & survival analysis in intra-arterial versus intra-venous PRRT.

Materials and Methods

Patients of inoperable neuroendocrine liver metastases or locally advanced NETs, either stable or progressive after at least two cycles of i.v. ¹⁷⁷Lu-DOTATATE PRRT or any liver directed therapy were randomised into intra-arterial & intra-venous arms. 11 patients of intra-arterial arm (2 patients with locally advanced pancreatic NET and 9 patients of hepatic metastases) & 21 patients of intra-venous arm (5 patients of locally advanced pancreatic NET and 16 patients of hepatic metastases) were followed up at 3 months & 6 months. Both arms were analysed for symptomatic improvement, anatomical imaging response with RECIST 1.1, molecular response with PERCIST criteria & clinical toxicity with NCI CTCAE criteria.

Results

Out of the 4 symptomatic patients, 2 patients showed resolution of symptoms in intra-arterial arm, while in intra-venous arm out of 18 symptomatic patients, 4 patients had alleviation of symptoms. In intra-arterial arm 4/11 patients had partial response, 6/11 had stable disease & 1/11 had progressive disease, while in intra-venous arm 2/21 had partial response, 16/21 had stable disease, 3/21 had progressive disease. Most common late adverse events were grade 1 or 2 haematotoxicity in both arms. No grade 3 or 4 haematotoxicity, renal or hepatotoxicity requiring any urgent intervention were observed in any of the arms. Intra-arterial arm had one incidence of post-PRRT carcinoid crisis, while none was observed in intra-venous arm. Intra-arterial arm had no mortality, while intra-venous arm had one mortality.

Conclusion

We conclude that intra-arterial PRRT is safe, tolerable and efficacious approach for treatment of inoperable hepatic metastases of NETs or locally advanced NETs and shows response in the cases which were either stable or progressive on standard intravenous PRRT.

ABAOCNMB156: Radiation Dosimetry of Salivary Glands in ¹⁷⁷Lu-PSMA Radioligand Therapy: Implications for Xerostomia and Treatment Safety

Smrutismaraki Dash, Aftab Hasan Nazar, Richa Mishra, Manish Ora, Prasanta Kumar Pradhan

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow

Introduction

Patients with metastatic castration resistant prostate carcinoma are often managed with 177-Lu radionuclide therapy targeting the PSMA antigen. This radioisotope emits beta particles characterized by a limited tissue penetration range, enabling precise targeting of malignant cells while minimizing harm to healthy tissues. Post treatment dosimetry helps us to assess the absorbed radiation dose of individual organs. This assessment enables to balance the radionuclide dose such that the lesion receives the maximum radiation and minimum radiation dose to the normal healthy organs.

Material and Methods

This is a retrospective study which included 6 male patients (mean age: 66.83± 7.81 years) who were diagnosed with metastatic castration resistant prostate carcinoma. 2 of them had undergone bilateral orchidectomy and 4 of them were receiving anti-androgen therapy. 3 of them received their first 177-Lu PSMA therapy, 1 received his 3^rd therapy and 2 of them received their 5^th therapy. They were given 177Lu PSMA therapy (mean dose: 153.27 ± 35.20 mCi). SPECT/CT was performed post therapy. Initially residence time was calculated for the parotid and submandibular glands individually from their Volume of interests (VOI) drawn manually. Dosimetry was performed on all patients using an identical protocol. The mean absorbed doses were estimated with OLINDA software.

Results

Dosimetry calculations revealed that the bilateral submandibular glands received total beta radiation dose of 0.451±0.21 mGy/MBq and the bilateral Parotid glands received total beta radiation dose of 1.67 ± 1.03 mGy/MBq. The mean beta radiation dose received by both the salivary glands was found to be 1.06 ± 0.95 mGy/MBq. The higher radiation exposure to parotid glands can be justified by their larger size and mass as compared to the submandibular glands.

Conclusion

For the salivary gland absorbed dose, a dose threshold of 25 Gy (for both the parotid and submandibular glands) is well established from EBRT to avoid long-term xerostomia. Mean dose to parotid glands within 20Gy causes minimal or no significant long term xerostomia. With respect to submandibular gland the mean dose is within 40 Gy. In our study we found that the absorbed doses to salivary glands remained within acceptable limits.

ABAOCNMB168: Role of Ga68-Pentixafor PET/CT in Evaluating Adrenal Lesions in Primary Hyperaldosteronism: A Case series highlighting CXCR4-Guided Surgical selection

Sakshi Dixit, Aftab Hasan Nazar, Amitabh Arya, P.K Pradhan

Sanjay Gandhi Post Graduate Institute of Medical Sciences

Introduction

Primary aldosteronism (PA) is the excess production of aldosterone from the adrenal glands, resulting in low renin levels, hypokalemia and high blood pressure. About 35% of the cases are caused by a single aldosterone-secreting adenoma (Conn’s syndrome). Symptoms include fatigue, high blood pressure, muscular aches and weakness, muscle spasms etc. Though CT scan helps in localization but is unable to comment on functionality of adenoma. AVS is standard investigation for lateralization and sub typing primary aldosteronism, but it’s technically challenging procedure. Pentixafor PET/CT, being non invasive investigation targetting CXCR4 over expression in the aldosterone secreting adenoma, is helpful in localisation, lateralization and indicating functionality of adrenal secreting adenoma, and thus emerging as a promising modality.

Material and Methods

Patients with primary aldosteronism (n=6)(mean age:40.5 ± 8.73 yrs, range: 32-55 yrs, M:F- 2:4) and adrenal mass lesion on CT scan, who were referred for Ga68-Pentixafor PET/CT between January 2025 to September 2025 were retrospectively analysed. All (100%) had complaint of young onset HTN with 3 patient (50%) having recurrent limb weakness. AVS could successfully be done in only 2 patients. Whole body images were acquired in 3D mode 25 mins after injection of 5 mCi of Ga68-Pentixafor using a dedicated LSO PET-CT scanner. Reconstruction of acquired data was performed to obtain fused PET/CT images in transaxial, coronal and saggital views.

Result

PET/CT showed positive CXCR4 expression in the adrenal lesion in 5 patients (83.3%) with mean SUVmax= 7.53 ± 4.73, suggesting functional adenoma. Out of these 5 patients, 3 patients (60%) underwent surgery whereas 2 patients (40%) were kept on medical management with regular follow-up, based on the avidity of tracer uptake. PET/CT findings matched with the histopathological diagnosis made after surgery in all the 3 patients (100%), therefore highlighting the accuracy of Pentixafor PET/CT.

Conclusion

Ga68-Pentixafor PET/CT aids in more precise localisation, lateralization and comments on the functionality of adrenal adenoma in primary aldosteronism patients. Therefore predicting the surgical outcome and guides in precise resection of aldosterone producing adenoma leading to maximum preservation of the normal gland. It correlated with clinical features (83.3%) and post operative outcomes (100%).

ABAOCNMB169: Theranostic Potential of Iodinated Galactosylated Chitosan for Selective Treatment of Hepatocellular Carcinoma

Gowri Nayak¹, Vasumathi Ramesh¹, Satyam Kumar¹, Maya P. Shetty¹, Sanjay Bharati¹

¹Department of Nuclear Medicine, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India.

Introduction and Aims

Hepatocellular carcinoma (HCC) represents a significant global health challenge, with limitations in current therapeutic and diagnostic modalities. Targeted delivery systems that combine diagnostic and therapeutic capabilities hold promise for improving HCC management. This study is aimed to synthesise and characterise iodinated galactosylated chitosan, a novel polymer designed for selective hepatic targeting and potential theranostic use.

Materials and Methods

Chitosan was first iodinated using a direct labelling method with chloramine-T as an oxidising agent. Subsequently, galactose moieties were conjugated to iodinated chitosan via activation of lactobionic acid’s carboxyl group through EDC-NHS chemistry. The final product was purified by dialysis and lyophilisation. Characterisation was performed by Fourier-transform infrared spectroscopy (FTIR) to assess bond formation, proton nuclear magnetic resonance (NMR) for structural confirmation, scanning electron microscopy with energy dispersive X-ray (SEM-EDX) for elemental composition and morphology, and liquid chromatography–mass spectrometry (LC-MS) to identify key molecular fragments.

Results

FTIR analysis demonstrated successful incorporation of iodine and galactose groups, evidenced by characteristic shifts in amide and hydroxyl peaks. NMR spectra confirmed iodine attachment at the glucosamine moiety and incorporation of galactose units. SEM-EDX showed the presence of carbon, nitrogen, oxygen, and iodine, with elemental analysis indicating efficient labelling. Mass spectrometry identified fragment ions corresponding to lactobionic acid, iodinated glucosamine, and galactose-iodine linkages. Combined, these analyses confirm the successful synthesis of iodinated galactosylated chitosan with appropriate liver-targeted features.

Conclusion

A novel iodinated galactosylated chitosan polymer has been successfully synthesised and characterised. This polymer demonstrates promising features for future development of liver-targeted theranostic agents, potentially enabling focused treatment and imaging of HCC.

ABAOCNMB181: A New Era of Digital Biopsy - Prediction of hormone receptor and ki67 status of breast cancer using 18-F FDG PET-CT radiomics based machine learning

Sreelakshmi Sujith, Melvika Pereira, Natasha Singh, Divya Shivdasani

P. D. Hinduja Hospital and Medical Research Centre

Introduction

This study assessed the ability of 18-F fluorodeoxy glucose positron emission tomography-computed tomography (8-F FDG PET-CT) radiomics to predict the hormone receptor (ER, PR, Her2) and ki67 status of breast cancer.

Materials and Methods

37 biopsy proven breast cancer cases (February 2025 - September 2025) were studied. 182 radiomic textural features of the primary breast lesion were extracted from the staging FDG PET-CT scan DICOM images by commercial texture analysis software package (LIFEx; https://www.lifexsoft.org/ index.php) and 164 features analysis. Data analysis was done using Orange data mining software (https://orangedatamining.com/). 10 features were shortlisted using ANOVA with a p<0.05. The bootstrapping approach was used. Random sampling (stratified) with a training set size of 80% and 50 repeat train/test used for model training. Model performance was evaluated with Area under the Curve (AUC), Classification accuracy (CA), F1 score, Precision, Recall and Matthews Correlation Coefficient (MCC).

Results

Four machine learning (ML) algorithms (Random Forest, support vector machine [SVM], k-nearest neighbor [kNN] and Neural Network) were studied. All four showed AUC>0.800 for ER and PR positivity prediction, with best results with SVM model showing an overall accuracy of 95.25% and 93.25% for ER and PR status respectively (for ER+ : AUC 0.980, CA 0.953, F1 0.973, Precision 0.972, Recall 0.974, MCC 0.781; and for PR+ : AUC 0.930, CA 0.932, F1 0.956, Precision 0.942, Recall 0.970, MCC 0.816). All ML algorithms scored >0.800 in predicting Her2 + status, with Neural Network having the best AUC score of 0.969, while Random forest had better score across the rest of the parameters (AUC 0.957, CA 0.932, F1 0.722, Precision 0.745, Recall 0.700, MCC 0.684). Ki67 scoring was categorized into >20% or <20%, with all ML algorithms performance >0.750. Random forest was superior in this case with AUC 0.893, CA 0.807, F1 0.796, Precision 0.847, Recall 0.750, MCC 0.619. Random forest showed an overall accuracy of 93.25% and 80.75% for Her2 and ki67 status prediction respectively.

Conclusion

PET-CT radiomics-based machine learning algorithms can help in detecting the hormone receptor and ki67 status of primary carcinoma breast lesion. SVM is superior in ER and PR positivity prediction while Random forest was better in case of Her2 and ki67.

ABAOCNMB182: In-vitro stability, radiolabelling optimization and %in-vivo biodistribution of ¹⁸⁸Re-N-DEDC/Lipiodol: Implications for locoregional therapy

Naresh Kumar, SHAMIM AHMED SHAMIM, PRIYANKA GUPTA, GEETANJALI ARORA, VIJU CHIRAYIL, SURESH SUBRAMANIAN, MADHAVA B. MALLIA

All India Institute of Medical Sciences, New Delhi

Aim/Introduction

A novel chelating agent, diethyldithiocarbamate (DEDC) was indigenously developed by BARC, Mumbai. The high lipophilic character and small molecular dimensions of the complex ¹⁸⁸Re-N-DEDC appear to be sufficient to ensure stable radio-compound in lipiodol. Therefore, studies are required to validate and optimize the labelling procedure to achieve high %RCP, %labelling yield, in-vitro-stability and biodistribution of ¹⁸⁸Re-N-DEDC/Lipiodol in inoperable HCC patients.

Materials and Methods

The lyophilized freeze-dried kits of DEDC were labelled with freshly eluted ¹⁸⁸Re-sodium-perrhenate from commercial ¹⁸⁸W/¹⁸⁸Re- generator. The radiolabelling conditions were optimized by systematically varying the pH from ~5 to >8 and incubation parameters (25°C for 15 min, or 55°C to 100°C in increments, each for 5 and 10 min). Further, %RCP of ¹⁸⁸Re-N-DEDC was checked. In-vitro stability of ¹⁸⁸Re-N-DEDC complex was checked in Human blood plasma up to 72 hours. Lipiodol was added in labelled ¹⁸⁸Re-N-DEDC complex only when the radiochemical purity was >90% and further assess the % labelling yield. Following femoral artery administration, in-vivo biodistribution was evaluated by acquiring whole-body planar and SPECT/CT images on a Mediso AnyScan® system at 2, 6, 12, 2-, 48, and 72-hours post-injection. VOI were drawn on reconstructed fused SPECT/CT images over the whole liver, tumor, and lungs to quantify the percentage of activity in these regions.

Results

Optimal conditions for radiolabelling of ¹⁸⁸Re-N-DEDC were achieved at pH 7 and incubation condition of 90°C for 5 minutes, resulting in the highest % RCP (94.4 ± 1.14%) and labelling yield (93.0 ± 1.58%). During the early incubation period (up to 1 hour), the complex remained relatively stable, with only minor reductions in % RCP- 92.2 ± 1.70% at 0.5 h and 89.4 ± 1.64% at 1 h, although a gradual decline in %RCP was observed over 72 hours with %RCP of 60.5 ± 2.17%. Quantitative SPECT/CT showed high liver uptake (79.90 ± 7.62% at 72h) and tumor retention of 73.21 ± 7.35% at 72h. Lung uptake (~13%) indicated hepato-pulmonary shunting, a common finding in inoperable HCC with arteriovenous communications.

Conclusion

Overall, the indigenously developed ¹⁸⁸Re-N-DEDC lipiodol formulation showed excellent preparation characteristics, high in-vitro stability, and favorable biodistribution, making it clinically feasible for targeted radionuclide therapy in inoperable HCC.

ABAOCNMB184: Safe Handling During Manual Preparation of 177LU Based Peptide

Manojkumar Chauhan, Arvind Suresh, Jay Prakash Kumar, Santosh Kumar Gupta

MPMMCC/HBCH, A UNIT OF TMC

Introduction: The manual preparation of radiolabeled peptides using Lutetium-177 (¹⁷⁷Lu) requires stringent safety practices to ensure the protection of personnel, the environment, and the integrity of the radiopharmaceutical product. ¹⁷⁷Lu is a beta-emitting radionuclide widely used in targeted radionuclide therapy, particularly for treating neuroendocrine tumors and prostate cancer. While its therapeutic benefits are well-established, its radioactive nature necessitates adherence to rigorous radiation safety protocols.

Aim: To determine the Radiation Exposure during manual preparation of ¹⁷⁷Lu based peptide. Methods and Materials: During the preparation of radiopharmaceutical and quality control of RP, pocket dosimeter was clamped on chest. Before preparation A Non carrier added (NCA) ¹⁷⁷LuCl₃ was measured. For the preparation of ¹⁷⁷Lu based peptide, a buffer solution was prepared by mixing ascorbic acid (40µg) and sodium ascorbate (160µg) with _PH of around 4-5. 100µL of suitable peptide according to the case and 900µL of Buffer solution was taken in Eppendorf and mixed well. The whole content was transferred in ¹⁷⁷LuCl₃ vial and mixed well. The vial is then heated for 25min at 90℃ and kept at RT. The RPs was transferred in vacuum vial through micro pore filter of 0.22µm. After preparation, the L bench and other area where handling of ¹⁷⁷Lu-peptide preparation performed, a radiation survey was done to check the limit of contamination. The final product was analyzed on iTLC scanner by performing quality control using sodium citrate as a solvent. The RCP was around 99% and retention factor was 0.10±0.012.

Result: The survey was done using GM counter and observed that the average radiation exposure was 0.02±0.002µSv/hr for three batches and it was very well the limit equivalent to background radiation exposure. Handling of the ready to use ¹⁷⁷Lu based peptide give the radiation exposure even less as compared to the manual prepared ¹⁷⁷Lu based peptide.

Conclusion: Safe handling during preparation of radiopharmaceutical ¹⁷⁷Lu based peptide used for therapy could give low radiation exposure to the radiochemist. As ¹⁷⁷Lu has β ray, there is chance of internal contamination and ϒ ray will give unwanted radiation exposure to the radiochemist. As compare to ready to use ¹⁷⁷Lu based peptide, this can instantly can be used when well maintained at room temperature. By following the safety rule while working in radiation area where open source is used will give low radiation exposure to personnel and prevent the spread of contamination.

ABAOCNMB192: Towards Harmonization of Internal Dosimetry: Comparison of Q.Thera AI and DTK + OLINDA/EXM in Lu-177 PRRT Patients using

Shubham Ghag, Pratiksha Kumkar, Shainesh Sonawane, Ashish Jha, Ameya Puranik, Venkatesh Rangarajan

ACTREC, Tata Memorial Centre

Introduction/Aim

Nuclear medicine utilizes radiopharmaceuticals that emit ionizing radiation for both diagnostic and therapeutic purposes. Following administration, these compounds circulate in the bloodstream and distribute across organs and tumors depending on physiological and pathological states. Accurate estimation of radiation absorbed doses in both tumors and healthy tissues is therefore critical to ensure therapeutic efficacy while minimizing toxicity. Internal dosimetry provides this information, yet results may vary across commercial software platforms, posing challenges for standardization. This study aimed to compare absorbed dose estimates derived from two widely used software solutions—GE’s Dosimetry Toolkit (DTK) combined with OLINDA/EXM v2.0 and Q.Thera AI—in patients undergoing Lu-177 DOTATATE peptide receptor radionuclide therapy (PRRT).

Materials and Methods

Eleven patients with histopathologically confirmed neuroendocrine tumors received Lu-177 DOTATATE therapy. Whole body planar imaging was performed at 4h, 24h and 72h whereas, SPECT/CT imaging was performed at 24 hours post injection. Organs of interest (liver, kidneys, spleen, lungs) and tumors were segmented to generate time–activity curves (TACs). Normalized cumulated activity (NCA) values were calculated and used as input for absorbed dose estimation in OLINDA/EXM v2.0 through DTK. Equivalent datasets were processed using Q.Thera AI for dosimetry calculations.

Results

The mean absorbed doses estimated using DTK + OLINDA/EXM versus Q.Thera AI were, respectively: liver 0.00242 ± 0.001 vs. 0.00258 ± 0.001 mGy/MBq; lungs 0.00119 ± 0.01 vs. 0.00122 ± 0.01 mGy/MBq; kidneys 0.00293 ± 0.0012 vs. 0.00323 ± 0.0012 mGy/MBq; spleen 0.00347 ± 0.002 vs. 0.00362 ± 0.002 mGy/MBq; tumors 0.40 ± 0.44 vs. 0.38 ± 0.47 mGy/MBq. Both platforms successfully provided absorbed dose estimates for all evaluated organs and tumors. Paired t-test analysis yielded a p-value of 0.45, indicating no statistically significant difference between the two software packages.

Conclusion

This study demonstrates that both DTK (with OLINDA/EXM v2.0) and Q.Thera AI provide reliable organ and tumor dose estimates in Lu-177 DOTATATE PRRT using hybrid method. The high correlation between results suggests comparability of the two tools, although Q.Thera AI may offer workflow advantages through automation. Larger, multicenter studies are warranted to further validate these findings and support harmonization of dosimetry software for routine clinical application.

ABAOCNMB193: Clinical Dosimetry in Lu-177 DOTATATE Therapy: Evaluation of Q.Thera AI and GE’s Dosimetry Toolkit with OLINDA/EXM using Multi SPECT method

Shubham Ghag, Shainesh Sonawane, Pratiksha Kumkar, Ashish Jha, Ameya Puranik, Venkatesh Rangarajan

ACTREC, Tata Memorial Centre

Aim/Introduction

In nuclear medicine, therapeutic radiopharmaceuticals deliver radiation doses to both target lesions and normal organs, making accurate dose estimation crucial for optimizing treatment outcomes while minimizing toxicity. Internal dosimetry enables calculation of absorbed doses to organs and tumors, but variability across software platforms may lead to inconsistencies. Harmonization of dosimetry methodologies therefore remains an important clinical objective. This study compares organ absorbed dose estimates from two commercially available dosimetry platforms—GE’s Dosimetry Toolkit (DTK) with OLINDA/EXM v2.0 and Q.Thera AI—in patients undergoing Lu-177 DOTATATE peptide receptor radionuclide therapy (PRRT).

Materials and Methodology

Six patients with histopathologically confirmed neuroendocrine tumors received Lu-177 DOTATATE therapy. SPECT/CT imaging was performed at 4, 24, 48/72, and 96 hours post-injection. Organs of interest (liver, kidneys, spleen, lungs) and tumors were contoured, and time–activity curves (TACs) were generated. Normalized cumulated activity (NCA) values were derived and input into OLINDA/EXM for absorbed dose estimation using DTK. Parallel datasets were analyzed using Q.Thera AI, which employs semi-automated segmentation and integrated dose calculation. Paired statistical comparisons were performed between both software outputs.

Results

Both DTK with OLINDA/EXM and Q.Thera AI successfully estimated absorbed doses for all evaluated organs and tumors. Paired t-test analysis resulted in p-value of 0.16, indicating no statistically significant difference between the two software platforms. Q.Thera AI results correlated closely with DTK + OLINDA/EXM, with minor deviations likely attributable to manual versus AI-based segmentation. Importantly, Q.Thera AI demonstrated faster processing times and reduced operator dependency owing to its semi-automated workflows.

Conclusion

Our study demonstrates that both DTK (with OLINDA/EXM) and Q.Thera AI provide reliable organ and tumour dose estimates for Lu-177 DOTATATE PRRT. Qthera AI holds superiority in handling clinical workflows due to its automation and integrated software. Furthermore, study should be conducted with larger cohorts to validate and harmonize these software for routine clincical applications.

ABAOCNMB203: Beyond the Angiogram: Stress MPI as a Gatekeeper for Revascularization and Outcomes

Rohit Bulchandani, Saloni Gadikar, Archita Sharma, Sunil HV, Bushra Sadeed

Deparment of Nuclear medicine, Mazumdar Shaw Hospital, Narayana Hrudayalaya, Bangalore.

Introduction

Coronary Artery Disease (CAD) prevalence in India has quadrupled over the past four decades. Myocardial perfusion imaging (MPI) noninvasively reflects the combined effects of epicardial, microvascular, and endothelial pathology, thereby representing the overall ischemic burden. The predictive value and clinical utility of MPI in patient management remain understudied in our country.

Aims

To evaluate the short-term predictive value of stress myocardial perfusion imaging with technetium-99m Sestamibi (MIBI) in patients with angiographically proven CAD.

Materials and Methods

In this single-center prospective observational study, 138 patients with angiographically proven CAD underwent stress MPI. Patients were followed for one year for the occurrence of Hard (death and myocardial infarction) and Soft events (revascularization or hospitalization).

Results

Among 138 patients (Normal = 58, Ischemia = 54, Infarct = 26), cardiac event rates differed significantly between groups (χ²=28.72, p<0.001). Event rates were highest in the Ischemia group (55.6%), followed by Infarct (30.8%) and Normal (8.6%). When analyzed as Ischemia versus non-Ischemia, the difference remained highly significant (p<0.001).

Revascularization rates also differed significantly (p=0.000005), with ischemic patients showing the highest rates, indicating a strong link between reversible perfusion defects and intervention. In univariate analysis, TID (OR≈10.7, p<0.001), Left Anterior Descending (LAD) artery involvement (OR≈11.7, p<0.001), and adenosine protocol (OR ≈ 4.1, p < 0.001) were significant predictors. Multivariate analysis showed LAD involvement (OR=7.79, 95%CI 2.67–22.76, p=0.0002) and adenosine protocol (OR=2.72, 95%CI 1.05–7.05, p=0.04) as independent predictors, while TID showed a nonsignificant trend. Age, gender, and diabetes were not significant.

Hospitalization occurred in 5 (9.3%) ischemic and 1 (1.7%) normal patients (OR=5.82, 95% CI 0.66–51.49, p=0.10).

Conclusion

Stress MPI identifies high-risk ischemic patients, with LAD ischemia and adenosine protocol use as significant independent predictors of soft cardiac events. Although hospitalization was higher in ischemic patients, it was not statistically significant due to the small sample size. The study underscores the prognostic value of stress MPI in guiding early revascularization or closer follow-up in CAD.

ABAOCNMB214: Evaluating Myocardial Viability in Late-Presenting Acute MI: A Comparison Between ^99mTc-MIBI SPECT and ¹³N-Ammonia/¹⁸F-FDG PET

Amisha Jamwal, Arun Singla, Harpreet Singh, Prashant Panda, Harmandeep Singh, Bhagwant Rai Mittal

Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012

Aim/ Introduction

Assessment of myocardial viability is crucial for guiding management in patients with late-presentation acute myocardial infarction (MI). This study aimed to compare the diagnostic performance of nitrate-augmented ^99mTc-MIBI SPECT with combined perfusion-metabolic PET imaging using ¹³N-ammonia and ¹⁸F-FDG for evaluating myocardial viability in patients presenting more than 72 hours after acute MI.

Material and Methods

Fifty-three patients with late-presenting acute myocardial infarction (MI) were prospectively enrolled and underwent sequential imaging with ^99mTc-MIBI SPECT and combined ¹³N-ammonia/¹⁸F-FDG PET within 48–72 hours of each other. For SPECT, a threshold of ≥50% of maximal tracer uptake was used to define viable myocardium. PET-based viability assessment was performed by comparing regional myocardial perfusion with metabolic activity, and areas demonstrating reduced perfusion but preserved metabolism were considered viable (hibernating) myocardium. Using PET as the reference standard, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of SPECT were calculated. Additionally, the extent of perfusion defects detected by MIBI SPECT was compared with ammonia PET on a lesion-by-lesion basis.

Results

Among the 53 patients analysed, 49 (92%) were male and 4 (8%) were female. The mean age of the study population was 57.1 ± 11.9 years. A total of 110 diseased vascular territories were evaluated across these patients. MIBI SPECT imaging identified 95 of these territories as non-viable and 15 as viable. Using PET as the reference standard, 40 of the 95 territories (42%) that SPECT classified as non-viable were viable. Conversely, all 15 territories identified as viable by SPECT were confirmed as viable on PET. Based on these findings, the sensitivity, specificity, PPV, NPV and overall diagnostic accuracy of MIBI SPECT were 100%, 27.2%, 57.9%, 100% and 63% respectively. In terms of perfusion assessment, 95 of the 110 territories showed comparable extent and severity of perfusion defects on both SPECT and PET. However, in 15 territories, SPECT overestimated the extent of the perfusion defect by more than 10% of the left ventricular (LV) myocardium.

Conclusion

MIBI SPECT, owing to its high negative predictive value (NPV), serves as a useful screening tool for ruling out non-viable myocardium in patients undergoing myocardial viability assessment. However, its major limitation lies in its low specificity for confirming non-viability. As a result, all vascular territories deemed non-viable on MIBI SPECT should undergo further evaluation with confirmatory imaging, such as (NH₃ + FDG) PET, to accurately determine myocardial viability

ABAOCNMB216: 68GA-PSMA PET/CT in Suspected Recurrent Gliomas: Precision in Differentiating Recurrence From Radiation Necrosis and Prognostication Through Tumor Burden

Raman Manojkumar Toshniwal, Sulochana Sarswat, Abhinav Singhal, Nishikant Avinash Damle, Madhavi Tripathi, Kalpa Jyoti Das, Ayan Dhiman, Aakash Aravindh, Anis Fomda

All India Institute of Medical Science, AIIMS New Delhi

Background

Differentiating true glioma recurrence from radiation necrosis after radiotherapy remains a major clinical challenge. 68Ga-PSMA PET/CT offers improved diagnostic accuracy and quantitative biomarkers with potential prognostic value.

Materials and Methods

In this prospective study, 49 patients with suspected recurrent gliomas underwent 68Ga-PSMA PET/CT. Quantitative PET parameters—primary tumor SUVmax (pSUVmax), SUVmean (pSUVmean), PSMA metabolic tumor volume (PSMATV), total lesion PSMA (TLPSMA), tumor-to-parotid ratio (TPR), and tumor-to-background ratio (TBR, referencing contralateral brain and IJV SUVmax) were measured. Recurrence was defined as tumor SUVmax > IJV SUVmax. Diagnostic accuracy for distinguishing recurrence from radiation necrosis was compared with MRI and clinical follow-up. Prognostic relevance for progression-free survival (PFS) and overall survival (OS) was assessed using Cox regression analyses.

Results

The cohort (mean age 39.8 ± 12.8 years; 41.9% male) had median PET metrics: pSUVmax 4.06 (IQR 3.17–6.07), pSUVmean 1.55 (IQR 1.15–2.12), PSMATV 16.89 (IQR 9.48–32.35), TLPSMA 25.30 (IQR 14.20–61.10), and TPR 0.52 ± 0.30. 68Ga-PSMA PET/CT indicated recurrence in 45/49 (91.8%) and necrosis in 4/49 (8.1%) cases. Follow-up confirmed 43 recurrences and 6 necroses, yielding sensitivity 97.7%, specificity 50.0%, positive predictive value 93.3%, negative predictive value 75.0%, and diagnostic accuracy 91.8%.

Median follow-up duration was 180 days; while median PFS and OS were 122 and 175 days respectively.

On univariate Cox analysis, predictors of shorter PFS included pSUVmax (HR 1.13, p = 0.039), PSMATV (HR 1.013, p = 0.007), TLPSMA (HR 1.005, p = 0.007), TPR (HR 6.30, p = 0.015), and TBR_IJV (HR 1.25, p = 0.008). For OS, TPR showed borderline significance (HR 8.05, p = 0.064).

In multivariate analysis, the best PFS model included PSMATV (HR 1.0466, p = 0.203), TLPSMA (HR 0.9683, p = 0.137), TPR (HR 22.70, p = 0.018), TBR_IJV (HR 0.996, p = 0.979), and gender (HR 2.97, p = 0.129) with concordance 0.70. The optimal OS model comprised pSUVmax (HR 0.597, p = 0.0401), TPR (HR 68.78, p = 0.0072), TBR_IJV (HR 1.143, p = 0.411), and gender (HR 3.425, p = 0.089), with concordance 0.704.

Conclusion

68Ga-PSMA PET/CT demonstrated high sensitivity (97.7%) and accuracy (91.8%) in distinguishing glioma recurrence from radiation necrosis. Among quantitative parameters, TPR was the strongest independent predictor of OS and a key prognostic marker for PFS. Volumetric metrics (PSMATV, TLPSMA, pSUVmax) also provided prognostic value, supporting the diagnostic and prognostic utility of 68Ga-PSMA PET/CT in post-treatment glioma assessment.

ABAOCNMB228: Impact of Lutetium-177 Dotatate Therapy On Clinical Outcomes and Quality of Life in Patients With SSTR Positive Neuro-Endocrine Tumors: A Prospective Study

Lakshmipratyusha Paladugula, Zakir Ali A, Prathyusha Bikkina, Ajit Nimmagadda

Basavatarakam Indo American cancer institute and research centre

Background

Neuroendocrine neoplasms (NEN) are often metastatic or inoperable at the time of presentation, with fewer treatment options. Peptide receptor radionuclide therapy (PRRT) targeting the SSTR expression of these tumors, appears to be promising in neuroendocrine neoplasms.

Objectives

The aim of this study is to evaluate the change in quality of life, biochemical markers and morphological response of Lu-177 DOTATATE in SSTR positive Neuroendocrine Tumors.

Methods

This is a Prospective Observational study done during July 2022 to June 2024, at the Department of Nuclear Medicine, Basavatarakam Indo-American cancer hospital and research Institute, Hyderabad. Patients with SSTR positive neuroendocrine tumors, who received 2 or more cycles of PRRT were included in the study. Treatment response following PRRT was evaluated with RECIST1.1 for anatomical imaging and EORTC c30 questionnaire was used to evaluate the quality of life.

Results

A total of 30 patients (13 males and 17 females) with SSTR positive neuroendocrine tumors were evaluated in this study. All the patients had undergone at least 2 cycles of Lu-177 DOTATATE therapy, with the number of cycles received ranging from 2 to 6. The primary sites of the NETs in our cohort were predominantly gastroenteropancreatic (23/30), followed by bronchopulmonary (4/30), unknown primary (1/30), and other locations (2/30). Out of the 30 cases, anatomical imaging revealed that 13 patients (43.3%) showed a partial response, 13 patients (43.3%) had stable disease, and 4 patients (13.3%) experienced disease progression. No complete responses were observed. Importantly, the study found a significant improvement in the patients’ overall quality of life, physical functioning, and symptom scales, such as fatigue and pain. Most adverse events reported were minimal, with majority being grade 1 or 2 in severity. Only one patient experienced grade 3/4 haematological toxicity. Furthermore, changes in biochemical markers, such as tumor markers, were found to correlate with the morphological responses observed in these patients.

Conclusion

PRRT therapy shows a good morphological response, biochemical response and significant improvement in quality of life in patients with SSTR positive neuroendocrine tumors irrespective of the tumor burden, primary site and age of the patients.

ABAOCNMB229: Diagnostic Utility of Liver Scintigraphy Indices in Non-Cirrhotic Portal Fibrosis and Cirrhosis

Santosh Kannur, Girish Kumar Parida, Manas Kumar Panigrahi, Kanhaiyalal Agrawal, P Sai Sradha Patro, T Kishan Subudhi

AIIMS Bhubaneswar

Background/Aims

Non-cirrhotic portal fibrosis (NCPF) and cirrhosis present with overlapping features of portal hypertension but differ significantly in prognosis and management. This study aimed to evaluate liver scintigraphy indices and biochemical parameters in differentiating NCPF from cirrhosis.

Methods

We retrospectively analyzed 29 patients with portal hypertension who underwent liver scintigraphy and biochemical evaluation. Based on final diagnosis, 19 patients had NCPF and 10 had cirrhosis. Quantitative indices—liver-to-spleen (L/S) ratio and liver-to-marrow (L/M) ratio—were compared using Welch’s t-test, and diagnostic accuracy was assessed with ROC analysis.

Results

Patients with NCPF had significantly higher L/S ratios (2.06 vs 0.90, p=0.031) and L/M ratios (67.6 vs 26.0, p=0.032) than cirrhotic patients. Bilirubin values were lower in NCPF (total: 1.59 vs 2.06 mg/dL; direct: 0.38 vs 0.87 mg/dL), though not statistically significant. ROC analysis showed that an L/S ratio cutoff of 0.86 yielded an AUC of 0.82, with 94% sensitivity and 60% specificity for identifying NCPF. An L/M ratio cutoff of 56.7 achieved an AUC of 0.74, with 42% sensitivity but 100% specificity. Clinically, hepatic decompensation (ascites, jaundice) was more frequent in cirrhosis, whereas NCPF patients predominantly had preserved hepatocellular function.

Conclusions

Liver scintigraphy provides robust discriminatory power between NCPF and cirrhosis. Elevated L/S and L/M ratios, especially an L/S > 0.86, strongly favor NCPF, while lower ratios indicate cirrhosis. Integrating these non-invasive indices with clinical evaluation can improve diagnostic accuracy, guide management, and prevent unnecessary transplant evaluation in NCPF patients.

ABAOCNMB233: A 7-Day Quality Control Assessment of a Germanium-68/Gallium-68 Generator

Carmel Frank Robin R, K K Kamaleshwaran, Ram Kumar E, Radhakrishnan E R, Kingsley F R, Arun Pandiyan, Aadhavan P, Jeba Getzi, Kowsalya R, Manoaj M

Nuclear Medicine Department, Kovai Medical Center and Hospital, Coimbatore, India.

Introduction, Aims

Gallium-68 (⁶⁸Ga) based radiopharmaceuticals are central to modern diagnostic imaging. Their production relies on 68Germanium/68Gallium (⁶⁸Ge/⁶⁸Ga) generators, which makes routine quality control essential to guarantee patient safety and diagnostic accuracy. Key quality control parameters include the generator’s elution yield and the level of radionuclidic impurity, specifically the ⁶⁸Ge breakthrough test. The aim of this study was to conduct a 7-day quality control assessment of a 68Ge/68Ga generator to evaluate its performance, consistency, and the purity of its eluate.

Materials and Methods

A quality control assessment was performed over a 7-day period, with generator elutions conducted on three separate days. All activity measurements for elution yield were performed using a dose calibrator. The dose calibrator’s constancy was first verified on each elution day using a Caesium-137 (¹³⁷Cs) reference source. The percentage yield was calculated by comparing the measured activity of the ⁶⁸Ga eluate to the theoretical activity expected on that day.

For the ⁶⁸Ge breakthrough test, an aliquot of the eluate from each of the three days was stored for 48 hours to allow for the decay of ⁶⁸Ga. The residual ⁶⁸Ge activity was then measured using a Sodium Iodide (NaI) scintillation well counter, autocalibrated, constancy and linearity checked, before measuring. The breakthrough percentage was calculated as the ratio of ⁶⁸Ge activity to the total eluate activity at the time of elution.

Results

The dose calibrator constancy check showed acceptable performance, with an average percent deviation of 2.079%. The generator demonstrated consistent and high elution yields across all test days, with an average yield of 93.53%. The ⁶⁸Ge radionuclidic impurity was found to be minimal. The average ⁶⁸Ge breakthrough was 0.00118087%. The detailed results from the three test days are summarized in the table below.

Conclusion

The 7-day quality control assessment confirmed that the ⁶⁸Ge/⁶⁸Ga generator is well-functioning and performs reliably. The ⁶⁸Ge/⁶⁸Ga generator consistently provided a high daily elution yield, averaging 93.53%. The radionuclidic impurity was minimal and well within established safety limits on all test days. This confirms the generator’s suitability for producing high-purity ⁶⁸Ga eluate for clinical use.

ABAOCNMB236: Quality Control Assessment of Expired Radiopharmaceutical Kits: Safety and Practical Considerations in Nuclear Medicine.

Ritwik Sinha^1,2, Arvind Suresh^1,2, Swayamjeet Satapathy¹

¹Mahamana Pandit Madan Mohan Malviya Cancer Centre and Homi Bhabha Cancer Hospital, Varanasi (A Unit of TMC, Mumbai), ²Homi Bhabha National Institute, Mumbai

Introduction

Radiopharmaceuticals play a vital role in the diagnosis and therapy of various diseases in nuclear medicine. These kits contain chemical reagents that, when labeled with radionuclides such as technetium-99m (⁹⁹ᵐTc), produce compounds used for imaging and functional studies. Each kit is assigned a manufacturer-specified expiry date based on stability and sterility data to ensure safety and accuracy of clinical results. However, due to supply constraints, high patient load, or delays in procurement, expired kits are sometimes evaluated for possible use after performing complete quality control (QC) testing. Proper storage under recommended refrigerated conditions (2–8 °C) can slow chemical degradation and potentially preserve labeling efficiency beyond expiry. Nevertheless, while some expired kits may pass QC tests, their routine clinical use is not advisable. This study aims to assess the QC performance of expired radiopharmaceutical kits and emphasize the importance of proper storage and regulatory compliance in nuclear medicine practice.

Aim

To evaluate the quality control parameters of expired radiopharmaceutical kits stored under recommended refrigerated conditions and determine whether such kits maintain acceptable labeling efficiency and purity for potential emergency use, while emphasizing that their routine clinical use is not recommended.

Materials and Methods

Commonly used ⁹⁹ᵐTc-based cold kits, which had exceeded their manufacturer-declared expiry date by one to six months, were selected for evaluation. All kits were stored in a temperature-controlled refrigerator (2–8 °C) as per standard storage guidelines. Freshly eluted sodium pertechnetate (⁹⁹ᵐTcO₄⁻) was used for labeling according to manufacturer instructions. QC testing included visual inspection, pH measurement, radiochemical purity (RCP) using instant thin-layer chromatography (ITLC), and sterility testing. Each parameter was compared with baseline data from in-date kits. Only kits showing ≥90% RCP and no visual or pH abnormalities were considered acceptable.

Results

Several expired kits stored under proper refrigeration retained satisfactory RCP (>90%) and normal pH (6.0–8.0) with no discoloration, turbidity, or particulate formation. Labeling efficiency remained comparable to that of non-expired kits, and sterility tests showed no microbial growth. Kits stored at room temperature failed QC due to reduced labeling yield and visible changes.

Conclusion

Certain radiopharmaceutical kits stored continuously under refrigerated conditions may temporarily retain acceptable QC characteristics even after expiry. However, their use in routine clinical practice is not recommended. Such kits may be considered only in emergencies, following comprehensive QC testing, documentation, and regulatory oversight.

ABAOCNMB248: Dynamic ¹⁸F-PSMA-1007 PET-CT Kinetics as a Prognostic Marker in Newly Diagnosed Prostate Cancer: A Prospective Study

Lakshmithulasi P, Patel Meet, Tarun Jain, Ram Singh Meena, Bagwant Rai Mittal

Mahatma Gandhi Medical College

Introduction

Prostate cancer remains a leading cause of cancer-related morbidity and mortality among men worldwide. Recent advances in molecular imaging, particularly Prostate-Specific Membrane Antigen (PSMA) PET-CT, offer improved diagnostic accuracy over conventional imaging.

Aim

This study evaluates the diagnostic and prognostic significance of dynamic PSMA PET-CT parameters, focusing on time-activity curve (TAC) patterns, and their correlation with serum PSA levels, Gleason scores, and CHAARTED defined disease volume in newly diagnosed prostate cancer patients.

Material and Methods

A prospective single-arm study was conducted at a tertiary care center in India, incorporating 29 patients with histologically confirmed, untreated prostate adenocarcinoma. Each patient underwent dynamic pelvic and delayed whole-body ¹⁸F-PSMA-1007 PET-CT imaging. TACs were generated from dynamic imaging and categorized into early and late crossing based on a 15-minute threshold. Patients were stratified by CHAARTED criteria (disease volume), Gleason score, and PSA levels. Statistical analysis included t-tests, chi-square tests, regression analysis, and correlation studies.

Results

Early TAC crossing was found in 69% patients and it was significantly associated with high disease volume (100%, p = 0.001) and higher serum PSA (p = 0.003). Late crossing patterns correlated with lower disease burden and 100% survival till time (2 yaers). Gleason score did not significantly correlate with disease volume or survival outcomes. TAC pattern was an independent predictor of disease volume (p < 0.0001).

Conclusion

Dynamic PSMA PET-CT imaging provides valuable diagnostic and prognostic information in newly diagnosed prostate cancer. Early crossing TAC patterns indicate more aggressive disease and poorer outcomes.

ABAOCNMB258: Diagnostic Accuracy of Robotic Arm assisted Real time PET-CT guided Biopsy of Abdomino-pelvic lesions including Retroperitoneal lesions

Arunravi John, JS Arora, Jeenu Varghese, Tvsvgk Tilak, Srivallabh Dande

Command Hospital Air Force

Introduction and Aim

This study aimed to assess the diagnostic accuracy of real-time PET/CT-guided biopsy of abdominal and pelvic lesions, including retroperitoneal lesions, using a robotic arm.

Methods

This retrospective study included 54 patients (32 men and 22 women; mean age, 49.6 ± 12.3 years; range, 22–74 years). All patients underwent real-time PET/CT-guided biopsies of tracer-avid lesions in the abdomen and pelvis from June 2023 to June 2025 after obtaining institutional ethical committee clearance. Among these patients, 15 had previously received inconclusive results from CT, ultrasonography, or transrectal ultrasound-guided biopsy. Biopsies were performed using an automated robotic arm with real-time PET-CT guidance. A semiautomatic soft-tissue biopsy gun (18G to 20G) with a coaxial needle was used. Biopsy samples were collected after confirming that the biopsy needle tip was within the target lesion on PET/CT. The selected lesions showed the highest metabolic activity or radiotracer expression. Histopathology reports were used to evaluate diagnostic performance. The duration of each procedure and the number of Check CTs performed were recorded. Clinical and/or imaging follow-up for up to six months confirmed negative results. The accuracy of the guided biopsy in diagnosis was evaluated by comparing it with a composite diagnosis. This composite diagnosis was determined through pathological examination and confirmed by clinical and/or radiological follow-up examinations. Results were classified as true-positive if histopathology confirmed either malignant or benign pathology. Results were considered true-negative if no evidence of disease was identified through pathology or follow-up. False-positive results occurred when histopathology incorrectly indicated an alternative pathology. False-negative results occurred when histopathology failed to reveal a diagnosis. Non-representative and inconclusive results were also classified as false negatives.

Results

Of the 54 patients, lesions were successfully targeted and pathologically diagnosed in 50 (92.6%). Of these, 38 were malignant and 12 were benign. The procedure took an average of 24 min (range: 12–35 min), with a mean of 2.9 check CT scans per biopsy. Three cases of residual FDG uptake post-malignant treatment were true negatives, confirmed by a six-month follow-up. The diagnostic results included 47 true positives, 3 true negatives, 4 false negatives, and no false positives. The sensitivity was 92.1% (95% CI: 81.12–97.82%), specificity 100% (95% CI: 29.24–100.00%), positive predictive value 100% (95% CI: 92.45–100.00%), negative predictive value 42.8% (95% CI: 22.65–65.77%), and accuracy 92.5% (95% CI: 82.11–97.94%). Bleeding occurred in four patients (three in the liver and one in the spleen) and was managed with gel foam injection. No serious complications or life-threatening events were observed.

Conclusions

The use of real-time PET-CT guidance with a robotic arm for percutaneous biopsy of metabolically active lesions in the abdomen and pelvis offers a precise, safe, and accurate method for pathological diagnosis (1,2). This approach demonstrated excellent diagnostic performance. PET-guided biopsy is especially beneficial for patients with previously inconclusive biopsy results (1,2). The use of a robotic arm also facilitates the performance of percutaneous PET-guided biopsies by enhancing the coaxial angulation and precision.

ABAOCNMB251: ROLE OF 68Ga-FAPI-46 IN NON-INVASIVE DETECTION AND PROGNOSTICATION OF RENAL FIBROSIS – INTERIM ANALYSIS OF A PILOT STUDY

Arunravi John, Arun Ravi John, Sambit Sundaray, Debasish Mahapatra, Jagdish S Arora, Srivallabh Dande

Command Hospital Air Force

Introduction and Aim

Renal fibrosis causes progressive loss of renal function. Histopathological confirmation of Interstitial Fibrosis and Tubular Atrophy (IFTA) is time-consuming and carries risks of complications. This pilot study evaluates PET imaging biomarkers using 68Ga-FAPI-46 for non-invasive detection and prognosis of renal fibrosis. The data presented are from an interim analysis.

Material and Methods

We recruited 20 patients with renal dysfunction who underwent routine renal biopsy as the study arm. We included 13 patients with normal renal function tests undergoing 68Ga-FAPI-46 for oncological indications as the control group. The recruited patients underwent detailed clinical evaluation, review of renal function tests, and estimation of eGFR. All recruited patients received an IV injection of 2.0–2.5 MBq/Kg of 68Ga-FAPI-46. PET-CT imaging was performed 60 min after radiotracer injection. Patients also received a diuretic, Inj Furosemide 0.5 mg/kg, after radiotracer administration. All patients were advised to void their urinary bladder before imaging to minimise any residual radiotracer in the renal collecting system. The Standardized Uptake Value mean (SUV mean) of liver was obtained by placing a spherical Volume of Interest (VOI) of 2 cm diameter for background calculation. The Standardized Uptake Value maximum was obtained from the renal cortices by placing a VOI of 1 cm diameter. The SUV max of the renal parenchyma was divided by the SUV mean of liver to calculate the Target-to-Background Ratio (TBR). The results in the study group were tabulated into three groups based on IFTA involvement of the sampled cortex: grade I (< 25%), grade II (25–50%), and grade III (>50%). We applied the Kruskal-Wallis test to test for differences among the groups. A P value < 0.05 was taken as statistically significant.

Results

Of 20 test arm patients, 14 were male (70%) and 6 female (30%). Mean age was 56.25 years; median, 60.5 years (range 35–71). Ten patients (50%) had IFTA Grade I (<25%), seven (35%) had Grade II (25–50%), and three (15%) had Grade III (>50%). Comparative PET data by IFTA grade between test and control groups are shown in the table.

Conclusions

The interim analysis suggests PET parameters from 68Ga-FAPI-46 could serve as quantitative biomarkers, aiding differentiation of renal fibrosis and damage. These markers may enable non-invasive assessment, support monitoring of pathology severity, and guide therapy and prognosis. Larger cohort studies are needed to refine cutoff values and validate their clinical use.

ABAOCNMB259: “Feasibility of Lightweight Deep Learning Architectures for Automated ⁶⁸Ga-PSMA-11 PET/CT Lesion Segmentation: Toward Real-Time Edge Deployment.”

Nandhagopan U S, Priyanka Verma, Yuva Raj Nitin Nitin, Bivinjith Nt, Sandip Basu

Radiation Medicine Centre, Bhabha Atomic Research Centre

Introduction and Aims

Automating lesion segmentation in prostate-specific membrane antigen (PSMA) PET/CT imaging can improve diagnostic efficiency and quantitative consistency. This project aimed to develop a deep learning-based segmentation model for prostate lesions that can calculate prostate-specific volume (PSV) and SUVmean. The model was also to be optimized for real-time use on an NVIDIA Jetson Nano edge device.

Materials and Methods

The three-month pilot project included a literature review, data annotation, and model development. We evaluated U-Net and its efficient variants, ultimately selecting MobileNetV3-UNet (pretrained) and LiteNext (ConvMixer-based) architectures. Due to a limited dataset (n=30), we modified the task from lesion-only segmentation to a multi-head model that predicts total and physiological uptake. This change aimed to improve anatomical learning and reduce false positives. We created ground-truth masks using 3D Slicer and standardized preprocessing in Python. An ablation study compared the baseline and simplified model variants, which we trained using Google Colab GPUs.

Results

Both models showed feasibility but experienced overfitting due to the small dataset size. The LiteNext-Simple model achieved the best validation Dice score (0.49), which was slightly higher than that of MobileNetV3-UNet (0.47). However, both scores were below clinically acceptable thresholds (greater than 0.7). Qualitative analysis confirmed correct identification of physiological uptake regions, showing the pipeline’s potential for edge deployment.

Conclusion

We established a complete workflow for developing lightweight ⁶⁸Ga-PSMA-11 PET/CT segmentation models. While the model efficiency was suitable for edge hardware, the performance was limited by the small dataset as it was a pilot project. Our future work focuses on expanding the datasets, testing other efficient backbones (such as EfficientNet and DFANet), and benchmarking TensorRT-optimized inference on Jetson Nano for real-time clinical application.

ABAOCNMB268: Unveiling The Theranostic Landscape of Osteosarcoma: Preliminary Results of A Prospective Comparative Study of Dual Tracer 18F-FDG and 68Ga-PSMA PET/CT in Treatment-Naive Osteosarcoma Patients

Roshan Karna, Raman Toshniwal, Ayan Dhiman, Love Kapoor, Kalpa Jyoti Das, Rakesh Kumar

All India Institute of Medical Sciences

Introduction

Osteosarcoma is the most common primary malignant bone tumor in adolescents and young adults. 18F-FDG PET/CT is widely used for staging, response evaluation, and prognostication in osteosarcoma. Prostate-specific membrane antigen (PSMA) has also been reported in the neo-vasculature of several non-prostatic malignancies, including sarcomas. Direct comparison of these tracers in untreated osteosarcoma remains largely unexplored. This study explores the potential role of PSMA PET/CT in treatment-naive osteosarcoma, compares and correlate quantitative parameters with conventional FDG PET/CT.

Materials and Methods

Histologically proven, treatment-naive osteosarcoma patients underwent both FDG and PSMA PET/CT within 1 month interval. Scans were analysed qualitatively for patterns of tracer uptake and quantitatively using parameters such as SUVmax, tumor-to-liver ratio (TLR), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) where feasible. Statistical analysis was performed using the Wilcoxon signed-rank test for paired comparison of FDG and PSMA parameters and Spearman’s rank correlation for inter-tracer relationships. A p value < 0.05 was considered statistically significant.

Results

In 21 treatment-naive osteosarcoma patients (mean age 19 years; Female = 11, M = 10), mean primary SUVmax was 12.44 ± 6.16 for FDG and 11.05 ± 9.96 for PSMA. FDG TLR (7.78 ± 3.59) exceeded PSMA TLR (3.68 ± 2.96). FDG volumetrics showed substantial tumor burden (MTV 465.19 ± 490.90 cm³; TLG 1980.37 ± 1958.54). PSMA-derived metabolic tumor volume (PMTV) and total lesion PSMA (TLP) demonstrated considerable interpatient variability, with mean MTV of 320.8 ± 340.4 cm³ and mean TLG of 754.7 ± 472.9. These findings underscore marked heterogeneity in PSMA expression and viable tumor burden within this cohort. Eleven (11) patients (52%) had metastases (predominantly pulmonary). There was no significant correlation between FDG and PSMA SUVmax (Spearman ρ = 0.12, p = 0.694) and no significant paired difference (Wilcoxon p = 0.3396), suggesting complementary rather than redundant imaging roles.

Conclusion

This study of treatment-naive osteosarcoma reveals distinct but complementary patterns of FDG and PSMA uptake. FDG PET/CT remains superior for delineating metabolic tumor burden. Dual-tracer interpretation could open avenues for PSMA-based theranostics in osteosarcoma. While FDG PET/CT remains the cornerstone for osteosarcoma imaging, PSMA PET/CT demonstrates uptake in both primary and metastatic lesions, likely reflecting tumor associated neo-vasculature. Larger, prospective and retention studies are needed to confirm these preliminary observations.

ABAOCNMB076: Assessing the role of [¹⁸F]F-FDG PET/CT in infective endocarditis of native valve, prosthetic valves, grafts, conduits and cardiac implantable electronic device infection.

Austin Saju, Sunita Sonavane, Sandip Basu

Radiation Medicine Centre, BARC

Introduction

Infective endocarditis (IE) is an uncommon but serious cardiac infection of native valve (NV), cardiac prosthesis (prosthetic valves, grafts, conduits) (CP) and cardiac implantable electronic devices (CIED). Its heterogeneous presentation delays diagnosis and contributes to high mortality. The modified Duke’s Criteria (mDC) remains the standard diagnostic tool and fares well in NV endocarditis but performs poorly in PV endocarditis and CIED infections. [18F]F-FDG PET/CT has demonstrated diagnostic value for PV endocarditis and CIED pocket infections and has been incorporated in the 2023 ESC guidelines (Class I evidence). In NV endocarditis, its role is limited to detecting extracardiac manifestations (Class IIB). The following study evaluates the diagnostic role of [18F]F-FDG PET/CT in these groups of patients.

Materials and Methods

Seventy-one patients with suspected NV, CP or CIED infection were prospectively enrolled and classified by modified Duke’s Criteria before [18F]F-FDG PET/CT and reclassified after it. Patients followed a high-fat, low-carbohydrate diet, ≥12 h fasting, and received intravenous unfractionated heparin prior to [18F]F-FDG injection for myocardial glucose suppression. Whole-body PET/CT was visually analyzed, with uptake deemed positive if above background and, for CP/CIED cases, present on both attenuation corrected [AC] and non-AC images. Quantitative lesional SUVmax for all cases and semi-quantitative ratios (SUVmax of abnormal prosthetic uptake/ Blood pool SUVmax) for CIED and CP cases were analyzed. The gold standard was the final diagnosis of the infective endocarditis committee [IEC] at discharge.

Results

Seventy-one patients with suspected cardiac infection [NV=35, CP=15, CIED=21] were enrolled. Dietary compliance was 85% (n=61). Six scans were uninterpretable due to inadequate myocardial suppression. Blood cultures were positive only in 13 patients, while echocardiography detected vegetations in 36/50 in both NV and CP cases but none in CIED. Final clinico-pathological diagnosis was available in 60 patients. Focal/multifocal [18F]F-FDG uptake suggestive of IE was observed in 37 cases [NV=11, CP=9, CIED=17] with mean SUVmax of 6.09±3.13. Sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] were 56.2%, 100%, 100%, and 50% for NVE (53% upgraded from possible to definite), and 70%, 100%, 100%, and 66% for CP (66% upgraded from possible to definite). For CIED superficial generator site infections, sensitivity, specificity, PPV, and NPV were 94%, 75%, 94%, and 75%, with prosthesis-to–blood pool ratio 2.3±1.3. Extracardiac findings (n=21) further aided diagnosis and management.

Conclusion

[18F]F-FDG PET/CT improves diagnosis of CP and CIED-related endocarditis, aids in evaluation of “possible” mDC cases, and detects silent emboli or concomitant infections through whole-body imaging.

ABAOCNMB136: A SPECT-Based semiquantitative scoring system for SSTR Expression Assessment Using Tc-99m HYNIC-TOC: Development and Interobserver Validation.

Hamid Althaf¹, Achal Goel¹, Deepanksha Datta¹, Rajesh Kumar¹.

¹ Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, India.

Introduction

Ga-68 DOTA-based PET/CT imaging is currently the best imaging modality for evaluating somatostatin receptor (SSTR) expression in neuroendocrine tumors (NETs), with standardized interpretation via the SSTR-RADS framework. However, it necessitates a reliable SPECT-based alternative in centers with no PET facility. This study proposes and validates a semi-quantitative scoring system—SPECT-RADS—using Tc-99m HYNIC-TOC SPECT/CT, based on tumor-to-liver ratio (TLR) and Krenning score.

Materials and Methods

This retrospective study included 37 biopsy-proven NET patients who underwent Tc-99m HYNIC-TOC SPECT/CT at our institution.

• ROI placement: The lesion with the highest uptake was identified and fully encompassed by a region of interest (ROI) on the section with the best visual delineation. The liver ROI was placed on the caudate lobe on a representative axial slice. The ROIs were normalized to their respective areas.

• Parameters calculated:

  • ○ Tumor-to-liver ratio (TLR), normalized to ROI area

  • ○ Krenning score (0–4), assigned visually

• A five-point SPECT-RADS score was defined as below:

Two observers—a junior resident (2^nd year) and a consultant—independently analyzed all scans and assigned TLR, Krenning, and SPECT.RADS scores.

Statistical Analysis:

• Fleiss’ kappa: Interobserver-agreement on Krenning and SPECT•RADS

• Intraclass correlation coefficient (ICC): For TLR reproducibility

• Spearman’s rank correlation: Association between TLR and Krenning score

Results

• SPECT-RADS agreement: Fleiss’ κ = 0.63 (substantial agreement)

• Krenning agreement: Fleiss’ κ = 0.57 (moderate agreement)

• TLR reproducibility: ICC = 0.857 (95% CI: 0.742–0.924) → excellent consistency

• Correlation between TLR and Krenning score:

  • Observer 1: Spearman’s ρ = 0.748, p < 0.001

Observer 2: Spearman’s ρ = 0.803, p < 0.001 → Strong positive correlations for both observers

Conclusion

A semi-quantitative scoring system combining TLR and Krenning score, demonstrated high reproducibility and interobserver-agreement, on Tc-99m HYNIC-TOC SPECT/CT. The SPECT-RADS framework, modeled on the PET-based SSTR-RADS structure, shows promise as an accessible, standardized alternative for assessing SSTR expression. Further prospective validation, direct comparison with the SSTR-RADS framework on Ga-68 DOTA-PET/CT, and evaluation of its prognostic potential are proposed directions for future study.

ABAOCNMB106: Beyond Cardiology: Clinical Applications of SMARTZOOM Collimator in Nuclear Medicine

Mohammed Bilal, Dr Valaiyapathy N C

Apollo Cancer Hospital

Introduction

Nuclear medicine imaging has undergone significant technological advancements aimed at improving image quality and diagnostic accuracy. One such development is the IQ-SPECT (Intelligent Quantification Spect) system which includes the use of a SMARTZOOM collimator, specifically designed to enhance photon sensitivity and spatial resolution in targeted regions. The application of this technology has shown promise in myocardial perfusion imaging, but its utility in other routine nuclear medicine procedures, such as DMSA scintigraphy and thyroid scintigraphy remains under-explored.

Aim

To compare and evaluate the clinical utility and image quality outcomes of the IQ-SPECT SMARTZOOM collimator and LEHR in renal cortical imaging using DMSA scans and functional thyroid scintigraphy.

Materials and Methods

This prospective study included 40 patients referred for nuclear medicine scans, subdivided into two groups: DMSA (n=20) and thyroid scintigraphy (n=20). All scans were performed twice on a dual-head SPECT gamma camera using both SMARTZOOM collimators and Low Energy High Resolution Collimator. Imaging parameters such as acquisition time, spatial resolution, and lesion detectability were analysed and compared between two collimators. Qualitative image assessment was performed by two experienced nuclear medicine physicians blinded to clinical data. Quantitative analysis included region-of-interest (ROI) based contrast measurements and count statistics.

Results

The use of the SMARTZOOM collimator resulted in a notable reduction of 30-40% in acquisition time without compromising diagnostic image quality. DMSA images demonstrated enhanced cortical definition, particularly in paediatric patients mean age of 8 years. Thyroid scans showed sharper glandular margins and improved visualization of nodular pathology. Observer agreement was high for all thyroid scans and Paediatric DMSA images. Image distortion in oblique images was observed in DMSA study of 100 % for adult patients and 20% for paediatric patients. The mean body surface area of patients with distorted oblique images was < 1.2 (m²) while mean Body surface area of rest of the patients was ≤ 1.07

Conclusion

The IQ-SPECT SMARTZOOM collimator offers significant advantages in DMSA, especially in paediatric population and Thyroid scintigraphy by improving image quality, reducing acquisition time, and enhancing lesion detectability. Its application in these routine scans can potentially streamline workflow and improve patient compliance, particularly in paediatric and high-throughput settings. Further large-scale studies are recommended to establish standardized imaging protocols.

ABAOCNMB078: To evaluate the role of ¹⁸F-FDG PET brain imaging in predicting short-term progression of mild cognitive impairment

Jubin Jacob, Julie Hephzibah, Justin Benjamin, Saumya Sunny, Junita John, David Mathew

Christian Medical College

Introduction

Mild cognitive impairment (MCI) represents a transitional stage between normal aging and dementia, with an annual conversion rate of 10–15% compared to 1–2% in the general population. Early prognostic differentiation is critical for management and therapeutic planning. ¹⁸F-FDG PET-CT detects hypometabolism as a marker of neurodegeneration, enhancing diagnostic precision by comparison with normative databases and enabling monitoring of disease progression.

Methodology

Patients with suspected cognitive decline underwent baseline clinical evaluation (MoCA and/or CDR) and ¹⁸F-FDG PET-CT brain imaging. Scans were analysed visually and quantitatively using 3D-SSP (GE Cortex ID) and Siemens Biograph TruePoint software against age- and sex-matched normative databases. Follow-up extended for ≥6 months. Two nuclear medicine physicians independently reviewed scans. SUVmax and Z-scores for regional hypometabolism were correlated with cognitive scores and clinical outcomes.

Results

Among 42 participants, 5 (11.9%) showed clinical progression at 6 months. Of these, 4 (80%) had baseline Frontotemporal Dementia (FTD)-related hypometabolism, and 1 (20%) showed an Alzheimer’s Disease (AD)-MCI pattern. The remaining 37 (88.1%)—with patterns consistent with DLB- related (Dementia with Lewy Bodies), AD-related, or amnestic MCI (aMCI)—remained stable. Quantitative PET analysis demonstrated significant SUVmax reductions with Z-scores above diagnostic thresholds.

Conclusion

Baseline FDG-PET hypometabolic patterns, particularly FTD- and AD-related signatures, predicted short-term progression in MCI, whereas DLB-, AD-, or aMCI-related patterns were associated with stability. Quantitative Z-scores and pattern recognition demonstrate prognostic utility, supporting FDG-PET as a valuable tool in early risk stratification of cognitive decline.

ABAOCNMB221: Production of High-Specific-Activity No Carrier Added ¹⁷⁷LuCl₃ Using an HPLC-Based Separation System

A.K. Sharma¹, B.K. Tiwary¹, N.C. Joseph¹, D. Kumar¹, P. Shetty², K.V.V. Nair², A. Mathur¹, S. Chakraborty², U. Pandey¹

¹Radiopharmaceuticals Program, Board of Radiation and Isotope Technology, Navi Mumbai, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai

Aim: The growing clinical importance of ¹⁷⁷Lu-based radiopharmaceuticals has increased the demand for no carrier added (NCA) ¹⁷⁷Lu. This study presents an HPLC-based separation system for rapid isolation of NCA ¹⁷⁷LuCl₃ from neutron-irradiated enriched ¹⁷⁶Yb targets via the ¹⁷⁶Yb(n,γ)→¹⁷⁷Lu reaction.

Materials and Methods: Enriched ¹⁷⁶Yb₂O₃ target was procured from M/s Trace Sciences, Canada while LN2, DGA, and UTEVA resins were obtained from M/s Triskem International, France. NCA ¹⁷⁷Lu was produced by neutron irradiation of enriched ¹⁷⁶Yb targets (150 mg) in the Dhruva reactor at BARC at a thermal neutron flux of ~1.0 × 10¹⁴ n·cm⁻²·s⁻¹ for 2 weeks. Irradiated target was dissolved in 0.1 M HCl (5–10 mL), and HPGe gamma spectrometry was carried to confirm the presence of ¹⁷⁷Lu.

Three sets of glass columns were prepared using LN2 and DGA resins, with each column packed with varying amounts of LN2 and DGA resin. All columns were connected in to an HPLC pump system with PEEK tubings. A syringe pump system was used for loading the irradiated solution onto the columns, and purification was carried out using an SA-100 HPLC column washing pump, which enabled controlled flow of eluents through the system. A GM tube-based radiation detector monitored the radioactivity eluting from the columns during separation.

Results: Production was carried out using 150 mg of enriched irradiated ¹⁷⁶Yb to yield ~1.5 Ci of ¹⁷⁷Lu activity. Processing through three-stage column purification system resulted in overall ¹⁷⁷Lu recovery of ~75%, completed within 7–8 h. HPGe analysis of irradiated feed solution showed that ¹⁷⁷Lu constituted ~50% of the total activity. Following purification, final ¹⁷⁷LuCl₃ product exhibited radionuclidic purity >99.99%, confirming highly efficient separation. Clinical utility of NCA ¹⁷⁷LuCl₃ was demonstrated by formulating and administering three patient doses of ¹⁷⁷Lu-PSMA-617, all of which met quality control criteria and yielded satisfactory clinical outcome.

Conclusion: The developed HPLC-based purification system enables efficient recovery of NCA ¹⁷⁷Lu from neutron-irradiated ¹⁷⁶Yb target. The final product complied with clinical standards demonstrating suitability for routine production of NCA ¹⁷⁷LuCl₃.

ABAOCNMB125: Precision in Action: PET-CT Guided High Dose Rate-Percutaneous Interstitial Brachytherapy (HDR-PIBT) Catheter Placement for Oligometastatic Liver Lesion in Thymic Carcinoma

Lt Col (Dr) Neeraj Kumar, Classified Specialist (Nuclear Medicine), Command Hospital (SC), Pune.

Co-author

Lt Col (Dr) Anurag Jain, Classified Specialist (Nuclear Medicine), Command Hospital (CC), Lucknow.

Introduction

High-Dose-Rate Percutaneous Interstitial Brachytherapy (HDR-PIBT) is a minimally invasive radiotherapy technique offering targeted treatment for oligometastatic liver and lung lesions. While CT guidance is commonly used for catheter placement, certain lesions—especially those not visible on standard imaging—require advanced localization techniques. This is where PET-CT guidance becomes indispensable.

Case Highlights: PET-CT Guided Intervention

59 years old gentleman of thymic carcinoma, who was treated with 4# NACT followed by definitive CCRT a year back and presently on Lenvatinib, presented with metastatic liver lesion on 18F-FDG PET-CT on follow up. US guided biopsy of the lesion showed metastatic deposit of a poorly differentiated carcinoma CD117 +ve, PAX8 +ve, CD5 +ve, P63 +ve and p40 -ve favoring squamous cell carcinoma in a known case of thymic carcinoma. An institutional tumor board opined for HDR-PIBT of the liver lesion due to inoperable medical condition of the patient. But the lesion was not discernible on ultrasound or non-contrast CT. To overcome this limitation, patient was planned for HDR-PIBT using a fluorodeoxyglucose (FDG) PET-CT scan on a GE PET-CT scanner. The metabolically active lesion, invisible on plain CT, were clearly identifiable on PET-CT scan.

A robotic arm, typically used for PET-guided biopsies was employed to precisely position the percutaneous needle into the tumor. This enabled accurate catheter placement for brachytherapy, ensuring optimal dose delivery to the target while sparing surrounding healthy tissue.

Material Methods and Workflow

Step 1: PET-CT scan identifies metabolically active lesion.

Step 2: Robotic arm targets lesion for needle placement.

Step 3: Catheter inserted via angiographic sheath.

Step 4: Planning CT with dummy source.

Step 5: Dose planning using Oncentra TPS.

Step 6: Treatment delivered via Elekta MicroSelectron HDR with Ir-192 source - 15 Gy/1# to the lesion in segment VI of liver.

Results and Clinical Impact

A response assessment PET-CT done after 3 months showed decrease in size and metabolic activity of the liver lesion with stable primary lesion suggesting a successful treatment and patient was continued on Lenvatinib.

PET-CT guidance enabled successful treatment of the lesions that would otherwise be inaccessible. This approach expands the applicability of HDR-PIBT to anatomically challenging or radiologically occult metastases, enhancing precision and therapeutic outcomes.

ABAOCNMB172: Initial experience with Empagliflozin for preparing patients with fasting hyperglycemia for FDG PET-CT study.

Piyush Chandra, Sheela Mc, Shraddha Sawant, Sparsh Yadav

Medcare Institute of Diagnostics

Aim

Incidentally detected fasting hyperglycemia (FH) is not uncommon in patients referred for FDG PET-CT leading to poor scan quality, scan delay/and or rescheduling. Sodium glucose co-transporter2 inhibitors (SGLT2i) are novel drugs which lower the blood glucose by blocking the renal tubular reabsorption of glucose with good oral bioavailability and rapid onset of action. In this study we explored the potential of single dose of SGLT2i as an alternative to IV Insulin to achieve the target blood glucose (BG) before PET-CT scans.

Patient and Methods

Observational study including patients planned for FDG PET-CT study with significant FH (FBG > 170mg/dl). Patient were administered 10/20mg of oral Empagliflozin (EMP) and BG were monitored upto 4 hours. FDG was injected when BG was reduced by more than 10% from baseline and/or below 200mg/dl. Impact of drug was assessed by evaluating the mean reduction in BG before FDG injection, by assessing the quality of PET-CT scans and any drug induced adverse effects on patients.

Results

Total of 24 patients with mean FBG 222mg/dl (range 170-334mg/dl) were included in study (6 males, 18 females, mean age 61y). 50% patients (mean FBG 220mg/dl) received 10mg and 50% patients (mean FBG 224mg/dl) received 20mg of EMP. Target BG levels was achieved in all patients, in 25% (n=6) by 2 hours, in 66.6% (n=16) by 3 hours and in 8% (n=2) by 4 hours with mean reduction in BG levels of 24.95% (Range: 11-49%). Mean BG at time of FDG injection was 163.6mg/dl (range 130-195mg/dl). No significant difference was seen in mean BG reduction in 10 mg vs. 20 mg dose groups (p- 0.39). Patient with mean FBG >200mg/dl had a significantly better reduction of BG compared to patients with FBG <200mg/dl (mean reduction 29% vs 20% respectively, p-0.004). Quality of PET-CT scans was satisfactory with good tumor to background uptake in various tumor subtypes. Except for a lower FDG uptake in brain, no significant alteration was noted in physiological distribution of FDG compared to controls. No adverse drug reactions were noted.

Conclusion

Oral Empagliflozin is a safe and effective alternative to intravenous Insulin for preparing patients with significant fasting hyperglycemia for FDG PET-CT study.

ABAOCNMB267: Head-to-Head Comparison of ⁶⁸Ga-FAPI-46 and ¹⁸F-FDG PET/CT in the Evaluation of Soft Tissue Sarcoma

Yogita Khandelwal, Shamim A Shamim, Bela Jain, Parth Baberwal, Sameer Rastogi

AIIMS, New Delhi

Background

Fibroblast activation protein (FAP) is highly expressed by cancer-associated fibroblasts and tumour cells in many soft tissue sarcoma (STS) subtypes. ⁶⁸Ga-FAPI-46 PET/CT offers high tumour-to-background contrast and theranostic potential. We prospectively compared the diagnostic performance of ⁶⁸Ga-FAPI-46 PET/CT with standard ¹⁸F-FDG PET/CT in metastatic STS.

Methods

In this single-centre prospective study (April 2024–September 2025), 61 adults with histologically confirmed metastatic STS underwent both ¹⁸F-FDG and ⁶⁸Ga-FAPI-46 PET/CT without intervening therapy. Images were read independently by two blinded nuclear medicine physicians. Lesion detection was assessed per-patient and per-lesion. Quantitative metrics included SUVmax, SUV mean, metabolic/tumor volumes (MTV/TV using a 40% SUV_max threshold), total lesion glycolysis (TLG) or total lesion FAPI uptake (TLF), and tumor-to-background ratios. Histopathology and ≥6-month follow-up served as the reference. Paired tests (Wilcoxon/McNemar), Spearman correlations, ROC analyses, and survival estimates (Kaplan–Meier; Cox PH) were performed; p<0.05 was significant.

Results

58/61 patients (95.1%) had FAPI-positive disease on ⁶⁸Ga-FAPI-46 PET/CT vs 52/61 (85.2%) on ¹⁸F-FDG. On a lesion basis (n=412), FAPI detected 384/412 (93.2%) lesions vs FDG 330/412 (80.1%). Median lesion SUVmax was higher for FAPI (10.2, IQR 5.8–18.4) than for FDG (6.5, IQR 3.2–12.1). Median TLG was 320 (IQR 110–980) versus median TLF 560 (IQR 190–1550) p<0.01). Higher baseline TLF associated with shorter progression-free survival (median PFS 6 vs 14 months for high vs low TLF; log-rank p=0.01; multivariable HR 2.1, 95% CI 1.2–3.8).

Conclusions

⁶⁸Ga-FAPI-46 PET/CT provides superior lesion detectability, higher lesion contrast, and greater impact on staging and management than ¹⁸F-FDG in metastatic STS, with a promising prognostic signal from whole-tumour FAPI burden.

Note: This is an ongoing study and more patients are getting recruited.

ABAOCNMB204: Comparison between FAPI over FDG PET in detecting locoregional disease and distant metastases in differentiated thyroid carcinoma of follicular cell origin – A Systematic Review and Meta-Analysis of Paired Test Study Design.

Gowri Sankar, Vishnukumar Rajaraman, Valli Priyaa, Gayane Aghakhanyan, Emanuele Neri, Lorenzo Faggioni, Dania Cioni

All India Institute of Medical Sciences (AIIMS) Kalyani

Introduction and Aim

Differentiated thyroid carcinoma (DTC) typically has an excellent prognosis. Challenges arise in radioiodine-refractory (RR-DTC). FDG PET/CT is recommended by the recent American Thyroid Association (ATA) guidelines, 2025, for detecting tumor recurrence and metastases in RR-DTC. Fibroblast activation protein inhibitor (FAPI) PET-CT targets cancer-associated fibroblasts, offering improved sensitivity in many epithelial cancers.

The aim of this systematic review and meta-analysis (SRMA) is to compare the performance of FAPI over FDG PET for detection of locoregional and distant metastatic disease in DTC of follicular cell origin, in studies using paired study design

Materials and Methods

This SRMA was based on the PRISMA 2020 statement and was registered in PROSPERO. Databases searched included PubMed, Web of Science, Embase, Scopus, Ovid MEDLINE, and EBSCO, up to June 27, 2025 using a structured search concept and with set Inclusion and exclusion criteria.

Duplicate removal and screening were done with Rayyan.ai. Data Extraction was done in Excel. Risk of bias and applicability concerns were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and QUADAS-C tools. Meta-analyses (MA) of sensitivity and specificity were performed using bivariate random-effects model. Sensitivity and specificity statistics and metaregression inputs were computed externally using STATA 15.0 and manually entered into RevMan.

Results

Of 512 records from databases, 332 duplicates were removed, with 180 screened. A total of 9 studies were included in the final systematic review, and only 3 were included in the meta-analysis (Table 1). QUADAS-2 showed predominantly low risk of bias with few unclear or high risk in reference standard.

Conclusion

FAPI PET offers diagnostic performance that is comparable to non-inferior, and in some cases superior to, FDG for detecting locoregional and distant metastases in DTC of follicular cell origin. This may help in planning FAPI-based radionuclide therapy in RR-DTC patients.

ABAOCNMB159: Targeted Radiopharmaceutical Therapy: Development of Copper-64 labelled Arabinogalactan for Hepatocellular Carcinoma

Priti Sule¹, Maya P Shetty¹, Anushree U¹, Pradip Chaudri², Sanjay Bharati¹

¹Department of Nuclear Medicine, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India, ²Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, India

Introduction and Aims

Hepatocellular carcinoma (HCC) is a major contributor to global cancer-related deaths. Standard treatment modalities—including surgical removal, organ transplantation, tumour ablation, transcatheter arterial chemoembolization (TACE), chemotherapy, and other interventional procedures—often provide only modest therapeutic outcomes. Although radionuclide therapy offers a promising approach, its effectiveness can be limited by challenges such as non-specific distribution within the body, inadequate specificity for tumour targets, and significant toxicity. One strategy to address these issues involves directing radionuclide carriers to receptors preferentially expressed on liver cancer cells, like asialoglycoprotein receptors (ASGPR). In this context, the present study focuses on the development of arabinogalactan conjugated with copper-64 (Cu-AGn), which is engineered for selective ASGPR binding and leverages the capabilities of copper as both a PET-CT imaging agent and a β-emitting radiation source for therapy.

Materials and Methods

Cu-AGn was synthesized via a two-step process involving amination of arabinogalactan followed by copper labelling through a co-precipitation technique. The obtained complex underwent comprehensive physicochemical characterization using fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), and scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX).

Results

Analyses confirmed conjugation of copper ions with aminated arabinogalactan through substitution at hydroxyl (-OH) and amine (-NH) groups primarily at C2, C3, and C4 positions of galactose, arabinose, and glucuronic acid residues, resulting in a bidentate metal ligand complex. Scanning electron microscopy displayed rough surface morphology with cuboidal structures. Elemental composition analysis revealed copper content indicating successful metal incorporation.

Conclusion

This study successfully developed and characterized a novel copper-64 labelled arabinogalactan complex with considerable potential for targeted radionuclide theranostics in HCC.

ABAOCNMB252: Initial versus Delayed PRIMARY Scoring on ⁶⁸Ga PSMA PET/CT in Suspected Prostate Cancer

BHILASH SELVARATNAM, SHANMUGA SUNDARAM P, PADMA SUBRAMANYAM, MANJIT SARMA

Amrita Institute of Medical Sciences

Introduction

⁶⁸Ga PSMA PET/CT is widely established for staging, biochemical recurrence, and therapy response assessment in prostate cancer. Its role in primary diagnosis remains less defined, though the PRIMARY score has been developed to identify intraprostatic malignancy, with scores ≥4 strongly predictive of clinically significant prostate cancer. Prior studies, including the PRIMARY trial and subsequent multicentric work, have demonstrated improved performance with delayed imaging. This study aimed to evaluate the diagnostic accuracy of initial and delayed PRIMARY scoring in patients with clinical suspicion of carcinoma prostate (CaP).

Materials and Methods

We retrospectively analyzed 25 patients (2017–2025) referred for ⁶⁸Ga PSMA-11 PET/CT with suspicion of CaP but without histopathological confirmation at baseline. Inclusion criteria: PIRADS 3 lesions, prior negative biopsy with persistent suspicion, or contraindications to MRI (pacemaker, metallic implants, claustrophobia). Patients without subsequent biopsy or follow-up were excluded. PET/CT was acquired at ~45 minutes post-injection with delayed pelvic imaging at ~120–180 minutes. PRIMARY scoring was applied. Histopathology following sextant biopsy was used as the reference standard. Appropriate statistical tests were applied.

Results

The mean age was 68.3 ± 8 years. Histopathology confirmed CaP in 15/25 patients (60%): Gleason grade (GG) III (n=3), GG IV (n=1), GG V (n=11). The remaining 10 showed benign pathologies (BPH, chronic prostatitis, granuloma). Initial PRIMARY scoring (cut-off ≥4): Sensitivity 100%, Specificity 71%, PPV 88%, NPV 100%, Accuracy 90%. Delayed PRIMARY scoring: Identical diagnostic performance (Sensitivity 100%, Specificity 71%, PPV 88%, NPV 100%, Accuracy 90%). No false negatives were observed; however, two false positives occurred, both in patients with benign prostatic hyperplasia demonstrating high PSMA uptake. These accounted for the lower specificity.

Discussion

Our findings confirm that PRIMARY scoring on PSMA PET provides excellent sensitivity and negative predictive value, ensuring no primary malignancy was missed. The false positives underscore a known limitation of PSMA uptake in benign prostatic hyperplasia or inflammation, which can mimic malignancy. Delayed imaging did not significantly improve diagnostic accuracy in our cohort, likely due to smaller sample size and patient selection.

Conclusion

PSMA PET PRIMARY scoring demonstrates robust diagnostic accuracy for suspected CaP, with very high sensitivity and NPV, making it a valuable triage tool in MRI-ineligible/ equivocal, biopsy negative patients but with high clinical suspicion. While delayed imaging may enhance specificity in larger cohorts, in our series the benefit was limited, and false positives remain a caveat.

ABAOCNMB227: Bridging the Gap: Evaluating indigenous ^99mTc-HYNIC-TOC SPECT/CT as a Cost-Effective Alternative to⁶⁸Ga-DOTANOC PET/CT in Neuroendocrine tumor Imaging

Mehul Taggar, Shamim A Shamim, Monika S Lall

All India Institute of Medical Sciences

Introduction and Aims

Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms that overexpress somatostatin receptors (SSTRs), enabling receptor-targeted imaging for diagnosis and staging. Gallium-68 DOTA-1-Nal3-Octreotide positron emission tomography/computed tomography (⁶⁸Ga-DOTANOC PET/CT) is the current gold standard for SSTR imaging owing to its high sensitivity and resolution. However, its widespread use is constrained by high costs, limited PET/CT infrastructure, and reliance on imported DOTA-peptides—challenges particularly relevant in resource-limited settings. In contrast, ^99mTechnetium- Hydrazinonicotinyl-Tyr3-Octreotide single-photon emission computed tomography/computed tomography (^99mTc-HYNIC-TOC SPECT/CT), an indigenously developed SSTR analogue, offers a cost-effective and widely available alternative. Despite this potential, limited clinical data exist validating its diagnostic performance. This study aimed to evaluate the diagnostic accuracy of ^99mTc-HYNIC-TOC SPECT/CT and directly compare its performance with ⁶⁸Ga-DOTANOC PET/CT in the same patient cohort.

Materials and Methods

This prospective observational study included 33 patients with histologically confirmed NETs. All patients underwent both ^99mTc-HYNIC-TOC SPECT/CT and ⁶⁸Ga-DOTANOC PET/CT. For HYNIC-TOC, a dose of 370–555 megabecquerels (MBq) was administered intravenously, with imaging performed 60–90 minutes post-injection. ⁶⁸Ga-DOTANOC PET/CT was conducted using standard institutional protocols. Histopathology and/or PET/CT findings served as the reference standard. Lesion-based and patient-based analyses were performed, calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy.

Results

For primary lesions, ^99mTc-HYNIC-TOC achieved 77.8% sensitivity (true positives=21, false negatives=6), with missed lesions mainly in the duodenum, rectum, ileum, and pancreas. For metastatic disease, sensitivity was 82.6% (38/46), specificity 100% (54/54), PPV 100%, NPV 87.1%, and accuracy 92%. Organ-wise, sensitivity was highest for liver metastases (100%), followed by lymph nodes (72.2%) and osseous lesions (40%). Overall, HYNIC-TOC demonstrated 80.8 % sensitivity, 100% specificity, 100% PPV, 79.4% NPV, and 89.0% accuracy.

Conclusion

The indigenous ^99mTc-HYNIC-TOC SPECT/CT is a reliable, cost-effective diagnostic tool for NETs, demonstrating excellent specificity and PPV with good sensitivity, particularly for hepatic lesions. While performance is less robust for nodal and skeletal metastases, careful interpretation of negative scans can mitigate diagnostic gaps. Comparison with ⁶⁸Ga-DOTANOC PET/CT confirmed reasonable concordance, supporting HYNIC-TOC as a viable imaging option in settings lacking PET infrastructure. With further validation, it may serve as an alternative or complementary tool to PET/CT in resource-limited settings.

ABAOCNMB124: Evaluation of the role of ¹⁸F-FDG PET in the diagnosis of Autoimmune encephalitis

Priyanka Verma, Sandip Basu, Shilpa Kulkarni, Swaleha Nadaf, Rahul Chakor

Radiation Medicine Centre, Bhabha Atomic Research Centre

Introduction

Autoimmune encephalitis (AE) is an inflammatory disorder of the brain associated with neurologic dysfunction. It is frequently a challenging diagnosis for the physician. The pathogenesis of AE involves the presence of autoantibodies against intracellular antigens (Hu, Ma2, GAD), synaptic receptors (NMDA receptor, AMPA receptor, GABA receptor, mGluR5, Dopamine receptor), ion channels, and other cell-surface proteins (LGI-1, CASPR2, DPPX; MOG, AQP4, GQ1b). (1)

Aims

To evaluate the role of ¹⁸F-FDG-PET in the diagnosis of AE

Materials and Methods

The Brain 18F-FDG PET scans performed on patients referred for evaluation of suspected autoimmune encephalitis between January 2023 and August 2025 were retrospectively analyzed. From institutional records, demographic information, clinical characteristics, antibody profiles, MRI results, and PET metabolic patterns were gathered. AE cases were categorized as either seronegative or antibody-positive. The ¹⁸F-FDG PET data was analysed visually and in dedicated Neuro-Q software.

Results: The cohort comprised of patientsaged 1–40 years (6 males and 9 females) with suspected AE with diverse presentations, including seizures, fever, behavioral changes, ataxia, and cognitive decline. They were all finally diagnosed to have AE by referring neurologists (n = 15; seronegative AE=8, LGI1-positive AE=3, NMDA-positive AE=4). ¹⁸F-FDG-PET revealed consistent patterns of regional hypermetabolism in the basal ganglia and medial temporal lobes, frequently accompanied by an anterior-to-posterior gradient of cortical metabolism. Notably, in several patients, PET abnormalities were present despite normal MRI findings, highlighting the added diagnostic sensitivity of metabolic imaging in early disease stages. In one patient with NMDA-positive AE, treatment response evaluation scan was done after 2 months and images revealed a significant decrease in metabolic activity in basal ganglia suggesting a response to administered treatment.

Conclusion: 18F-FDG PET reveals distinct yet overlapping metabolic signatures in autoimmune encephalitis subtypes. Basal ganglia hypermetabolism is a common hallmark, while medial temporal involvement favors LGI1-positive AE. Particularly in patients who are seronegative, incorporating the results of FDG PET into the diagnostic workup can improve early detection, direct treatment and evaluate treatment response.

ABAOCNMB127: Synthesis and Quality Control of [¹⁸F]AlF-NOTA-Octreotide for PET Imaging of Neuroendocrine Tumours

Amit Kumar, Lakshminarayanan N, Avik. Chakraborty, G. Arjun, Nawab Singh Baghel

Bhabha Atomic Research Centre

Introduction

Neuroendocrine tumours (NETs) commonly overexpress somatostatin receptors, enabling targeted imaging with radiolabelled peptide analogues. Currently, [⁶⁸Ga]DOTA and [⁶⁸Ga]NOTA-conjugated octreotide derivatives are widely used for clinical imaging of NETs due to their high affinity for SSTRs and established clinical utility. However, the short half-life and occasionally limited availability of ⁶⁸Ga generators restrict large-scale or centralized production. In contrast, fluorine-18 offers advantages such as a longer half-life (110 min), cyclotron-based large-scale production, and favourable imaging resolution. The aluminium fluoride [¹⁸F]AlF chelation strategy provides a straightforward approach to incorporate fluorine-18 into NOTA-conjugated peptides, offering an attractive alternative to ⁶⁸Ga-labeled tracers.

Aims

To synthesize [¹⁸F]AlF-NOTA-Octreotide using an optimized radiolabelling protocol and to evaluate its quality control (QC) parameters for radiopharmaceutical application.

Materials and Methods

NOTA-octreotide peptide precursor and aluminium chloride were obtained from certified commercial suppliers. ¹⁸F-fluoride was produced via the ¹⁸O(p,n)¹⁸F nuclear reaction using a medical cyclotron. Sep-Pak cartridges, sterile filters, and formulation reagents (ethanol, saline, buffer components) were procured from certified commercial suppliers. All chemicals used were of analytical grade and solutions were prepared using ultrapure water under aseptic conditions. NOTA-conjugated octreotide was radiolabelled with fluorine-18 via the [¹⁸F]AlF method under controlled conditions of pH, temperature, and reaction time. In our optimised labelling procedure ¹⁸F was labelled with aluminium chloride in the presence of ethanol and sodium acetate buffer. The labelled [¹⁸F]AlF was heated with NOTA-Octreotide in Sodium acetate buffer to produce [¹⁸F]AlF-NOTA-Octreotide. Purification was achieved using solid-phase extraction cartridges. Radiochemical purity (RCP) was analysed by radio-HPLC and radio-TLC. The other physicochemical and biological QC were performed as per standard protocol.

Results

The synthesis of [¹⁸F]AlF-NOTA-Octreotide was achieved with reproducible RCY of 15 % (non-decay corrected) and RCP consistently >95%. The final formulation demonstrated pH within the acceptable physiological range, sterility, negligible endotoxin content, and no detectable residual solvents. The radiotracer retained >95% stability for up to 6 hours post-synthesis.

Conclusion

A reliable and efficient protocol for the synthesis of [¹⁸F]AlF-NOTA-octreotide was established, meeting all radiopharmaceutical QC specifications. The simplicity and robustness of this approach support its potential for clinical translation in PET imaging of NETs.

ABAOCNMB133: FDG-PET/CT guiding management of Sternal Wound Infection Following Sternotomy

Presenting author and First author: Dr Sanjana Sajeev

Co Authors : Dr Manjit Sarma, Dr S Abhilash

Department of Nuclear Medicine, Amrita Hospital, Kochi

Introduction, Aims

FDG PET CT is useful in diagnosing sternal wound infection (SWI), a serious postoperative complication of sternotomy. However, literature on impact of FDG PET-CT on patient management remains scarce. The purpose of this study is to assess the role of 18 F FDG PET CT in guiding management decisions.

Materials and Methods

A single-center, retrospective review of 7 patients who had undergone sternotomy (6 CABG, 1 aortic valve replacement) presenting with chronic sternal wound infection and who had underwent FDG-PET/CT imaging between 2015 to 2025 was conducted. 6 patients had undergone previous debridements. Mean age is 68 ± 3 years, male to female ratio is 5 :2, average duration from surgery to onset of infection is 7 ± 2 months and mean SUV Max was 7±0.7. Pus culture was done for 4 patients identifying Coagulase negative Staphylococcus aureus in 3 and Pseudomonas Aeruginosa and Acenitobacter Baumanni in 1 patient.

Extent of involvement in sternum, soft tissue, ribs on both CT and FDG, subsequent management, influence on management decisions by FDG PET-CT were documented and reviewed.

Results

Out of 7 patients, 5 showed increased FDG uptake and CT changes of sternal osteomyelitis (suggestive of deep sternal wound infection) with 2 of them showing rib involvement and one showing extension into costochondral junction. 4 of these 5 patients underwent wound debridement tailored to FDG PET CT findings including rib and costochondral debridement. However, one patient was managed conservatively with antibiotics as the patient had mild clinical symptoms.

Among the two remaining patients, 1 patient had soft tissue involvement on FDG PET CT (suggestive of superficial sternal wound infection) and was managed conservatively with antibiotics. The other patient showed no FDG PET-CT evidence of infection and was put on surveillance with no active intervention.

FDG PET CT directly influenced the management of 6 out of 7 patients.

Conclusion

FDG PET CT is an effective tool in determining deep and superficial SWI and influencing management of these patients by planning the extent of debridement for deep SWI patients and directing conservative management in patients with superficial SWI.

ABAOCNMB105: Analysis of image quality by regulating beta function of BSREM reconstruction algorithm and comparison with conventional reconstructions in prostate cancer patients

Priya Sharma, Dheeraj Jangir, Sakshi Dogra, Ram Singh Meena, Tarun Kumar Jain

Mahatma Gandhi University of Medical Sciences & Technology

Introduction

The study aimed to evaluate the beta penalization factor of the Block sequential regularized expectation maximization reconstruction algorithm (BSREM) on a GE Discovery IQ PET CT (3 ring BGO based) and compared it with conventional reconstructions.

Materials and Methods

A total of 7 patients with histopathogically proven prostate cancer were included in a prospective observational monocentric study. 68Ga-prostate specific membrane antigen (68Ga-PSMA-11) PET and contrast-enhanced-CT (CECT) was performed at our centre. Images were reconstructed with Ordered subset expectation maximization (OSEM), OSEM + point spread function (PSF), and BSREM under variable β factors 600, 800 and 1000. Liver noise, lesion Maximum Standardised Uptake Value (SUVmax), Signal to Background ratio (SBR), and Signal to Noise ratio (SNR) for each reconstruction were calculated. Quantitative parameters of each beta factor of BSREM were compared with OSEM and OSEM + PSF, using the Wilcoxon sign rank test with, a value of P < 0.002 was considered statistically significant. Visual scoring was done by two experienced Nuclear Medicine Physicians.

Results

overall, fourteen lesions were identified. Liver noise and SBR were reduced, whereas SNR was increased with an increasing β value of BSREM. Liver noise values decreased significantly in order from highest in OSEM, then OSEM-PSF, β 600, β 800 & lowest on β 1000. In comparison with OSEM, liver noise was significantly lower in β 1000 with values of 0.175 and 0.09, respectively.

SNR of OSEM was significantly lower than β factor 1000 and SBR of β factor 1000 less was significantly higher than OSEM.

Conclusion

The study quantitatively indicates the optimum beta range of β600-800 and the qualitative evaluation indicates that β800 is an optimum beta factor of BSREM in prostate cancer cases for 68Ga-PSMA-11 PET CT.

ABAOCNMB223: Ki-67 and NETPET in Neuroendocrine Tumors: Bridging Histology and Imaging for Prognostic Insight

ANJANA S S, N SASIREKHA, KABILASH D, NANDINI PANDIT

JAWAHARLAL INSTITUTE OF POSTGRADUATE MEDICAL EDUCATION AND RESEARCH

Introduction

Neuroendocrine tumors (NETs) exhibit variable biological behavior. The Ki-67 index remains the gold standard for grading; the NETPET score, based on PET imaging, has been proposed as a novel prognostic tool. The relationship between these parameters remains unclear.

Aim

To evaluate the correlation between Ki-67 index and NETPET score in patients with NETs in a tertiary health care Centre.

Materials and Methods

Data from patients with available Ki-67 and NETPET values were collected over 2 years. The data collected were summarized using descriptive statistics. Normality was tested with the Shapiro–Wilk method. Correlation was assessed using Spearman’s rank test, and linear regression was applied to evaluate predictive value.

Results

39 patients’ data were analyzed and Ki-67 indices were non-normally distributed (Shapiro–Wilk W = 0.672, p < 0.001), with a median of 5.5% (IQR 3.5–12.25), range 1.5–30%.

NETPET scores were non-normally distributed (Shapiro–Wilk W = 0.804, p < 0.001), with a median of 2 (IQR 2–3), range 1–5. Correlation analysis revealed a weak positive association between Ki-67 and NETPET score (Spearman’s ρ = 0.223). Higher NETPET scores tended to align with increased Ki-67 values, though the relationship was not strong.

Spearman’s rank correlation demonstrated a weak positive but non-significant association between Ki-67 index and NETPET score (ρ = 0.24, p = 0.13). Linear regression analysis further indicated that Ki-67 correlated with an R² value of 0.062.

Conclusion

Both Ki-67 index and NETPET score provide prognostic insights in NETs, but their weak correlation suggests that they reflect complementary aspects of tumor biology. Histopathological results reveal only the characteristics of a single site, while imaging modality helps in the whole-body assessment. Integration of imaging-based and histopathological biomarkers may thus enhance patient stratification and individualized management.

ABAOCNMB089: Comparative Diagnostic Performance of 68Ga-PSMA PET/CT and MRI in Initial Staging of Biopsy-Proven Prostate Cancer: A Prospective Study

Vigneshwaran M¹, Pandit AG², Vishnoi MG³

¹Graded Specialist (Nuclear Medicine), INHS Asvini, Mumbai, ²Senior Advisor (Med) & Nuclear Medicine Specialist, CH(SC), Pune, ³Classified Specialist, Nuclear Medicine, Army Hospital R&R, New Delhi

Background

Accurate initial staging of prostate cancer is critical for treatment planning. This prospective study compares the diagnostic efficacy of 68Ga-PSMA PET/CT with multiparametric MRI (mpMRI) in patients with biopsy-proven prostate carcinoma and investigates correlations with serum PSA levels and Gleason score.

Materials and Methods

Fifty-eight treatment-naïve patients with histopathologically confirmed prostate cancer underwent mpMRI and 68Ga-PSMA PET/CT imaging. Lesion detection, T- and N-staging, skeletal and visceral metastases were evaluated and compared. SUVmax was recorded, and its correlation with serum PSA levels and Gleason score was assessed.

Results

68Ga-PSMA PET/CT detected intraprostatic lesions in 93.1% of patients. T-staging was concordant with MRI in 82.7% of cases. Regional lymph node metastases were identified in 24 patients on PET/CT versus 16 on MRI. Skeletal metastases were identified in 43 patients with PET/CT and 27 with MRI. PET/CT upstaged disease in 18 patients based on non-regional nodal and osseous lesions. A significant correlation was observed between SUVmax and PSA ≥10 ng/mL (p<0.001), and higher Gleason scores showed increased tracer uptake.

Conclusion

68Ga-PSMA PET/CT demonstrates superior lesion detection and staging accuracy over mpMRI, particularly in nodal and distant metastases. SUVmax correlates significantly with tumour aggressiveness, suggesting PSMA PET/CT as a valuable tool in primary prostate cancer staging.

ABAOCNMB160: PEPTIC POWER PLAY: Detecting Hidden Gastrinomas in Zollinger-Ellison Syndrome with Ga-68 DOTATATE Imaging- A Case Report

Prabhjot Singh, Braj Kishore, M G Vishnoi, Vaibhav Jain

Army Hospital Research and Referral

Introduction

Zollinger Ellison syndrome (ZES) results from gastrin secreting neuroendocrine tumours located primarily in duodenum or pancreas leading to pathologic gastric acid hypersecretion, refractory peptic ulcer disease and secretory diarrhoea. The estimated incidence of ZES is 1 in 1 million with an average 5 year delay from symptom onset to diagnosis. Accurate biochemical confirmation and precise anatomical localization is vital, as cure of localized gastrinomas depends on complete surgical resection, while tumour burden and somatostatin receptor (SSTR) status determine choice and expected benefit of systemic therapies. This case report highlights the role of Gallium-68 DOTATATE for localizing, staging and therapeutic stratification of hidden gastrin secreting neuroendocrine tumour in a patient with biochemical evidence of ZES when conventional imaging and endoscopic sampling was inconclusive.

Case Details

A 42yearold male presented with 2 months of diarrhoea, vomiting and weight loss. Investigations included contrast-enhanced (CECT) abdomen, upper gastrointestinal endoscopy with biopsy, serum gastrin, FDG PET/CT and Ga-68 DOTATATE PET/CT.

• Histopathology of endoscopic biopsy from stomach showed features of chronic inflammation and moderate dysplasia without invasive carcinoma.

• CECT and FDG PET/CT demonstrated diffuse FDG uptake with circumferential gastric and duodenal wall thickening, initially raising concern for linitis plastica.

• Serum gastrin levels were markedly elevated at 1,040 pg/mL.

• Ga-68 DOTATATE PET/CT identified multiple intensely SSTR avid lesions in the pancreas, largest measuring 2.4 × 2.2 cm in head of pancreas (SSTR SUVmax-65.77), consistent with welldifferentiated neuroendocrine primary disease and multiple SSTRavid regional lymph nodes (largest 7 mm; SSTR SUV max- 22.61 in perigastric station). Furthermore, diffuse SSTR avid gastric wall thickening correlated with endoscopic ulceration and hypertrophic gastric folds, attributable to acid hypersecretion rather than primary gastric malignancy.

Conclusion

Ga-68 DOTATATE PET/CT provided accurate localization and staging in ZES where conventional imaging, FDG PET/CT and endoscopic sampling were unable to reveal the underlying pathology. Identification of intense SSTR expression enabled confident neuroendocrine tumour diagnosis, guiding surgical planning and established eligibility for peptide receptor radionuclide therapy (PRRT) in unresectable or metastatic disease. Ga-68 DOTATATE PET/CT therefore constitutes a critical diagnostic and theranostic tool in the modern management algorithm for ZES.

ABAOCNMB210: “Familial MEN syndromes identified by F-18 FDG PET CT functional imaging with biochemical correlation”

Hemanth Penagadam, Kalawat Tekchand, Ramya Priya R

Sri Venkateswara Institute of Medical Sciences

Introduction

Multiple endocrine neoplasia (MEN) syndromes are autosomal-dominant disorders with high penetrance, usually familial but sometimes sporadic. MEN 1 syndrome is due to inactivating MEN1 gene mutation, located on chromosome 11, resulting parathyroid, gastro-enteropancreatic neuroendocrine, and pituitary tumors. MEN II A syndrome is due to activating RET mutation located on chromosome 10, leading to medullary thyroid carcinoma and pheochromocytoma. Multi-gland, sometimes non-endocrine involvement leads to varied presentations, making early clinical diagnosis difficult.

Aim

To illustrate various presentations of familial MEN syndromes on F-18 FDG PET/CT with biochemical correlation.

Materials and Methods

Whole body F-18 FDG PET CT was performed done for two patients (Case I & Case II) in 2024.

Case I: A 44-year-old man with history of weight gain since 1 year and intermittent abdominal discomfort and pain in left flank since 2 months, with abdominal lipomas and collagenomas on examination.

Case II - A 23-year-old female, with marital history since 2 years undergoing work up for infertility and irregular menstrual cycles since menarche. Family history reveals neck swelling is present in sister, father, paternal aunty.

Results

Conclusion

Due to heterogenous manifestations in MEN syndromes, early diagnoses and syndromic association are difficult to establish. FDG PET CT by providing both functional and anatomical information, helps in facilitating early lesion discovery, guiding therapy options, and tracking treatment response. Hence FDG PET/CT with accuracy and non-invasiveness can be useful tool in the diagnosis and management of MEN disorders as early diagnosis and intervention can significantly reduce morbidity and mortality.

ABAOCNMB180: Somatostatin Receptor Expression in Renal Cell Carcinoma—An Alternate Approach to Diagnose and Treat Renal Cell Carcinoma- A Case Report

Vaibhav Jain, Braj Kishore, Madan Gopal Vishnoi, Aditya Bakshi, Prabhjot Singh

Army Hospital Research and Referral Delhi Cantt

Introduction

Renal cell carcinoma (RCC) is the most common solid tumor of kidneys. The most common histological subtype is clear cell RCC. Conventional CT is the standard investigation for monitoring and detection of recurrent disease. RCC metastases are difficult to distinguish from primary tumors and cytologic examination is not a viable option. Clear cell variant of RCC shows low/ variable 18F-FDG uptake and might result in missing residual or metastatic lesions.

⁶⁸Ga-DOTANOC PET-CT is used in neuroendocrine tumors (NETs) with high tumor to nontumor contrast and allows for the detection of small NET lesions.

In this case report it has been shown that metastatic lesions of RCC which are difficult to identify with conventional imaging can be identified using octreotide scintigraphy.

Case Details

A 58 years old male underwent left-sided nephrectomy in 2016 for clear cell RCC. In 2024, on follow-up, he underwent conventional CT, a 2-cm tumor was detected in peripancreatic region. Ultrasound-guided cytologic examination of the peripancreatic lesion showed atypical cells. Further investigation could not distinguish whether the lesions represented a NET or other pathology. 18F-FDG PET-CT showed mild metabolic activity in the peripancreatic lesion and another isodense lesion with mild metabolic activity in left deltoid muscle. Ga-68 DOTANOC PET/CT revealed intense SSTR expression in both lesions. Biopsy was done from deltoid lesion which was positive for metastasis of RCC. He was started on immunotherapy and subsequent response assessment ⁶⁸Ga-DOTANOC PET/CT showed significant decrease in size and SSTR expression of both lesions.

Discussion

SSTR-2 is expressed by tumor cells in primary clear cell RCC and corresponding metastases. DOTANOC is therefore expected to bind to SSTR-2 in RCC metastases, enabling its use as a functionally more specific method than FDG-PET and conventional CT.

Even after nephrectomy of locally confined disease, ≤ 30% of patients will develop metastases. Effective staging of RCC and early treatment can affect therapeutic decisions and alter disease outcomes. FDG-PET/CT might not be conclusive in the detection of metastases. DOTANOC PET/CT can be a useful imaging modality in detecting RCC metastasis, especially in cases in which the findings from other radiologic techniques are not conclusive.

Conclusion

SSTR-2 is expressed by tumor cells in both primary tumor and metastases of RCC suggesting it’s utility as a useful imaging modality in the management of metastatic RCC. These findings provide new insights into pathology of RCC and contribute to the development of new treatment methods of metastatic RCC.

ABAOCNMB190: Diuretic 18F-fluorodeoxyglucose (FDG) PET/CT imaging for detection of locoregional primary and recurrence of urinary bladder Cancer

N Sasirekha, Anjana S S, Kabilash D, Dhanapathi Halanaik

Jawaharlal Institute of Postgraduate Medical Education and Research

Aim

Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose(FDG) has been used with limited success in the past in primary diagnosis and locoregional recurrence of urinary bladder cancer, mainly because of the pharmacokinetics of renal excretion of 18F-FDG. In this case, we have demonstrated the application of diuretic 18F-FDG PET/CT in improving detection of urinary bladder tumors.

Case

A 77yrs/M patient is presented with a carcinoma bladder. Contrast enhanced computed tomography (CECT) revealed polypoidal sessile lesions involving left lateral urinary bladder wall, right lateral bladder wall and bladder neck region with mild upstream left HUN (hydroureteronephrosis). He underwent a complete TURBT (Transurethral Resection of a Bladder Tumour). 18F-FDG PET CT was done to look for residual tumors. A dose of 4.2mci was administered intravenously and imaging was done with bladder full protocol once and after giving intravenous diuretic - furosemide(40mg of lasix), imaging was done again. In the early image, no bladder lesion was visualised. In the delayed image, FDG avid irregular wall thickening of the bladder wall noted at two separate sites; one at the left lateral wall and another at the posterior wall. The wall thickening at the left lateral wall has a thickness of ~8mm with SUVmax:4.62.

Discussion

The first image showed intense uptake in bladder due to urinary tracer excretion which is physiological, hence the lesions in the bladder walls were masked. But the later image which is acquired after giving diuretics and voiding, the lesions in the bladder walls were well enhanced.

Conclusion

This case illustrates that diuretic protocol in 18F-FDG PET/CT highly plays an important role in improving detection of the residual primary tumor and locoregional recurrence of urinary bladder tumors.

ABAOCNMB205: Pancreatic metastases – a rare late bloom from renal cell carcinoma on FDG PET-CT

Meivel Pa, Meivel P A, Brinda R, Bharadhwaj K, Kavisankar K V

PSG Institute of Medical Sciences & Research

Introduction

Renal cell carcinoma (RCC) is the most common urogenital malignancy in adults accounting for 90 – 95% kidney tumors. The common histopathological subtypes are clear cell and papillary carcinoma. FDG PET-CT has limited role in the initial staging of RCC. Nevertheless, it is useful in the detection of recurrence and metastases. The incidence of RCC metastasizing to pancreas is rare and occurs at a later stage.

Case Discussion

We present a series of three patients diagnosed with renal cell carcinoma who underwent nephrectomy and detected with pancreatic metastases on follow up FDG PET-CT, arising after a decade post-surgery (12 – 21 years).

Case 1:

A 77- year female, known left renal cell carcinoma (clear cell variant), post nephrectomy in 2005. She was on tyrosine kinase inhibitor. FDG PET-CT in 2023 revealed multiple new FDG avid lesions in pancreas along with a mass in left renal fossa and bilateral lung nodules (time interval - 18 years).

Case 2:

A 70-year male, known right renal carcinoma (clear cell variant), post nephrectomy in 2011. Follow up FDG PET-CT in 2024 revealed an increase in the size and FDG uptake of lesion in left kidney with multiple lesions in pancreas and liver (time interval - 13 years).

Case 3:

A 54-year male, known left renal cell carcinoma (clear cell variant), post nephrectomy in 2012. He is currently on tyrosine kinase inhibitor (Sunitinib). Follow up FDG PET-CT in 2024 revealed an increase in size and FDG uptake of bilateral lung lesions with appearance of new FDG avid mediastinal lymph nodes and enhancing lesion in pancreas (time interval - 12 years).

Discussion

The unpredictable metastatic behavior and late recurrences from renal cell carcinoma have been reported, sometimes appearing decades after nephrectomy. The common metastatic sites include lungs, bones, and liver, whereas pancreatic metastases are rare, accounting for less than 5%. Interestingly, RCC is one of the few malignancies where pancreatic metastases can remain isolated and indolent for years. FDG PET-CT has an established role in detecting late and atypical metastatic sites. The treatment options include surgical metastatectomy, targeted therapy (tyrosine kinase inhibitors), or immunotherapy, depending on disease extent. Notably, patients with isolated pancreatic metastases have better prognosis compared to those with widespread disease.

Conclusion

Renal cell carcinoma can exhibit late and atypical metastatic spread, even years after nephrectomy. FDG PET-CT plays a vital role in detecting such rare metastatic sites, enabling timely intervention and appropriate management.

ABAOCNMB086: 18-F FDG PET/CT AND 99M-TC TRODAT-1 SPECT IN THE EVALUATION OF PARKINSONISM

Jayesh M, Indirani M, Shelley S

Apollo Hospitals Chennai

Introduction

Parkinsonism encompasses neurological disorders characterized by tremors, rigidity, and slowed movements, with Parkinson’s disease (PD) being the most common. Early diagnosis of PD is challenging because symptoms often overlap with atypical parkinsonian syndromes (APS). Advanced imaging techniques, such as 99mTc TRODAT-1 SPECT and 18F-FDG PET-CT, provide insights into dopamine transporter activity and brain metabolism, aiding differentiation between PD and APS. Combining information from both scans may enhance diagnostic accuracy. This study investigates the role of semi-quantitative analysis using these modalities together to better distinguish PD from other parkinsonian disorders, potentially improving early detection and clinical decision-making.

Aim

To evaluate combined 99mTc-TRODAT-1 SPECT and 18F-FDG PET-CT in differentiating Parkinson’s disease subtypes.

Materials and Methods

This cross-sectional analytical study was conducted in the Department of Nuclear Medicine, Apollo Hospitals, Chennai, from December 2022 to December 2024. Thirty-two patients clinically diagnosed with Parkinson’s disease (PD) or atypical parkinsonian syndromes (APS) were included. For SPECT imaging, 99mTc-TRODAT-1 prepared from a lyophilized kit was administered intravenously, and scans were acquired 4 hours post-injection using a Siemens T6 dual-head gamma camera. For 18F-FDG PET-CT, patients fasted for 6 hours before tracer injection, and images were obtained 60 minutes later on a Siemens PET/CT scanner. Regions of interest over basal ganglia were manually drawn to calculate TRODAT uptake ratios and FDG Z-scores. Imaging findings were correlated with clinical scores (H&Y, UPDRS) and analyzed using SPSS v22.0, with p < 0.05 considered statistically significant.

Results and Conclusion

A total of 32 individuals with parkinsonian syndromes were assessed, with an average age of around 64 years, and males making up the majority (75%). The most frequent diagnoses were Multiple System Atrophy and Parkinson’s Disease Dementia. All participants showed reduced dopamine transporter activity on Tc-99m TRODAT-1 SPECT imaging. The average cognitive score (MMSE) was 24.3, and the mean UPDRS score was 55.1, with the illness lasting approximately 22 months on average. FDG PET/CT scans indicated notable metabolic reductions, especially in the parietal and occipital lobes, more prominently in conditions like DLB and PDD. Dopaminergic activity was best preserved in IPD, while PSP showed the most significant loss. Statistically strong inverse relationships were observed between dopamine uptake and clinical severity (H&Y stage, motor, and UPDRS scores). Differences in imaging findings across diagnoses and disease stages suggest that using both FDG PET and TRODAT SPECT together provides valuable insights for distinguishing parkinsonian disorders and evaluating disease progression.

ABAOCNMB119: Associations of TSH and Anti-TPO with Vitamin B12 and Vitamin D Levels in Thyroid Dysfunction

Chandrakala Gholve^1*, Ashwini Pawar², Kinjalka Ghosh², Smita Gawandi¹, Nawab Singh Baghel¹

¹Radiation Medicine Centre, BARC, C/O TMH Annexe, Parel, Mumbai-400 012, ²Biochemistry Department, TMH, Parel, Mumbai

Introduction

Thyroid dysfunction is a common endocrine disorder influenced by both autoimmune mechanisms and nutritional status. Thyroid-stimulating hormone (TSH) and anti-thyroid peroxidase antibodies (TPOAb) are key biochemical markers used to assess thyroid function and autoimmunity. Emerging evidence suggests that micronutrients such as vitamin B12 and vitamin D may play a role in thyroid health through their involvement in immune regulation and metabolic pathways. However, the relationship between these micronutrients and thyroid markers remains inconsistent across studies.

Aims

This cross-sectional study investigates the relationship between thyroid function markers, particularly thyroid-stimulating hormone and anti-thyroid peroxidase antibodies and serum levels of Vitamin B12 and Vitamin D in patients diagnosed with thyroid dysfunction.

Materials and Methods

Study subjects: A total of 192 individuals were enrolled, including 142 patients with hypothyroidism or hyperthyroidism and 50 healthy controls.

Biochemical Assays: Thyroid function was assessed by measuring TSH, FT4, and TT4 using validated radioimmunoassay (RIA) and immunoradiometric (IRMA) methods. Serum 25-hydroxyvitamin D [25(OH)D] and vitamin B12 levels were measured using chemiluminescent microparticle immunoassays (CMIA) on the Alinity i analyzer (Abbott Diagnostics, Chicago, IL, USA).

Statistical Analysis: Pearson’s correlation examined relationships between vitamins B12 and D with TSH and anti-TPO. Multiple linear regression assessed TSH and anti-TPO as outcomes, with vitamin levels as predictors (β, SE, p, R²). Significance was set at p < 0.05, considering group status.

Results and Discussions

Regression analysis revealed a statistically insignificant negative correlation between TSH and both Vitamin D (R² = -0.036, p = 0.6) and Vitamin B12 (R² = -0.031, p = 0.7) levels. Similarly, anti-TPO levels demonstrated a negative correlation with Vitamin B12 (R² = -0.12, p = 0.1), whereas the association with Vitamin D was weak and non-significant (R² = -0.069, p = 0.414). Mean Vitamin B12 levels were higher in patients than controls, possibly reflecting impaired cellular uptake or altered binding protein regulation, suggesting functional deficiency despite elevated serum levels. Vitamin D levels were lower in patients, supporting its role in autoimmune thyroid pathology. These findings highlight the complex relationship between micronutrients and thyroid function and stress the need to assess both biochemical and functional vitamin status in thyroid disease. Further longitudinal studies are warranted to clarify the therapeutic role of supplementation.

Conclusion

Patients with thyroid disorders showed elevated TSH and anti-TPO levels, lower Vitamin D, and higher Vitamin B12, but no significant correlations with thyroid markers were observed, highlighting the complex relationship between micronutrients and thyroid function.

ABAOCNMB183: “Seeing Beyond MRI: 99mTc-ECD SPECT in Paediatric focal lesional Epilepsy”

Ramya.S¹, Manishi. L. Narayan*, P.K. Panda², Indar Kumar S², J. Chaturvedi³, S. Sarath¹

¹Department of Nuclear Medicine, ²Department of Paediatrics, ³Department of Neurosurgery, AIIMS Rishikesh, *Corresponding Author: Prof. Manishi L Narayan, Head, Dept. of Nuclear Medicine, AIIMS, Rishikesh

Introduction

The cerebral perfusion and metabolism alter drastically during and after seizure¹. Nearly 50% of children with focal seizures are known to have an underlying aetiology and high risk of developing drug-resistant epilepsies and eventually warranting surgery². Inter-ictal brain-SPECT, while less sensitive than ictal-SPECT in detecting epileptogenic foci, offers valuable insights, particularly when conventional imaging methods yield inconclusive or conflicting results. This additional information can assist in making informed decisions regarding management, ultimately enhancing disease management and improving patient outcomes.

Aim

To observe the scintigraphy features in paediatric focal lesional epilepsy (FLE) at a tertiary care hospital.

Materials and Methods

This Prospective Observational study, conducted in Department of Nuclear Medicine at AIIMS-Rishikesh, in population <18 years attending Paediatric Neurology OPD, with diagnosis of FLE. Interictal-brain perfusion-SPECT was performed using 0.2-0.3mCi/kg of 99mTc-ECD. Tracer was slowly injected intravenously, with patient at rest in a dim light room with eyes open. Imaging was acquired 45-60minutes post-injection. Location of perfusion defects were analysed both visually and using semi-quantitative methods.

Results

A total of 38 children (29-male & 9-female) with focal lesional epilepsy were analysed.

Out of these, 10/38 (26%) had Right focal seizures, 17/38 (45%) had left focal seizures, 6/38 (15.7%) had unclassified focal seizures and rest 5/38 (13%) patients have generalized seizures. EEG performed revealed concordant findings with 10/38 (26%) patients and discordant findings in 28/38 (74%), out of which 18/38 patients showed normal EEG records, but with focal perfusion defects on Inter-ictal Brain SPECT.

Brain MRI with epilepsy protocol revealed, mesial temporal lobe sclerosis as the commonest pattern (n=11, 28%), white matter abnormalities in 26% (n=10), malformations of cortical development in 5 children (13%), calcified/ inflammatory granuloma in 6/38 children, vascular abnormalities in 3 children, Rasmussen’s encephalitis in 2 patient and Arnold Chiari malformation in 1 child.

Inter-ictal brain perfusion SPECT, showed concordant sites of defects in 33/38 (86%) patients, with additional site of defects identified in 23/38 (60%) cases. Most of the additional sites of perfusion defects were temporal lobe hypoperfusion followed by pre-frontal, orbito-frontal, pre-cuneus defects.

Conclusion

The current study with Inter-ictal brain SPECT in children with FLE showed additional sites of brain perfusion defects, not identified on conventional imaging. This has allowed neurologists in knowing extent of brain cortical defects, improving their understanding of the disease and facilitated in tailored management for seizure control, through adjusting antiepileptic drug (AED) dosages or adding medications, as most patients opted against surgery.

ABAOCNMB077: Primary thyroid sarcoma with extremely high fdg avidity: role of pet/ct in staging and disease assessment

Kartikey Solanki, Dr Mg Vishnoi, Dr Anurag Jain, Dr Brajkishore, Dr Abhishek Mahto, Dr Abhinav Jaimini

Government of India

Introduction

Primary sarcomas of the thyroid are extremely rare, comprising less than 1% of all thyroid malignancies, with varied subtypes such as synovial sarcoma and undifferentiated pleomorphic sarcoma reported. These mesenchymal tumors present diagnostic challenges due to nonspecific clinical and radiological features, often mimicking other thyroid neoplasms. FDG PET/CT has increasingly been recognized as a valuable tool in staging and assessing the extent of disease. This report highlights a case demonstrating exceptional FDG avidity with metastatic spread.

Materials and Methods

A 49-year-old male presented with progressive hoarseness and a solid-cystic mass on the left side of the neck measuring 10×12 cm. Contrast-enhanced CT of the neck revealed a mass in the left visceral space with cervical lymphadenopathy. Serum thyroglobulin was elevated (26.50 ng/ml). FDG PET/CT was performed for comprehensive disease staging.

Results

PET/CT showed a large, lobulated, heterogeneously FDG-avid lesion (6.8×6.7×10.3 cm) involving the left thyroid lobe with an unusually high SUVmax of 94.8, central necrosis, and microcalcifications. The lesion displaced adjacent vasculature and crossed the midline, closely abutting the trachea and esophagus. Multiple FDG-avid metastatic sites were noted, including left prevertebral lymph node, bilateral lung nodules, and mediastinal lymph nodes. Immunohistochemistry confirmed a diagnosis of primary thyroid sarcoma, subtype unspecified.

Conclusion

This case illustrates the value of FDG PET/CT in delineating extensive disease burden in primary thyroid sarcoma, a rare but aggressive malignancy with high FDG uptake. The exceptional SUVmax observed underscores the tumor’s aggressive nature and aids in differentiation from other thyroid neoplasms. PET/CT findings were pivotal in staging and influencing management decisions. Early multidisciplinary evaluation and histopathological confirmation are essential for optimal outcomes in such rare thyroid malignancies.

ABAOCNMB260: Role of F-18 FDG PET/CT as a Functional Imaging Tool in suspected in suspected Encephalitis: A Series of 3 Cases.

Priyanshu Sharma, Dr Tekchand Kalawat, Dr Ramya Priya Rallapeta

Sri Venkateswara Institute Of Medical Sciences

Introduction

Encephalitis is the inflammatory disorder of brain arising from multiple infectious and non-infectious etiologies. Patients typically present with neuropsychiatric symptoms, memory impairment, seizures, or movement disorders. Diagnosis in early disease stages remains challenging since standard imaging technique like magnetic resonance imaging (MRI) frequently shows normal findings. In this context, F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) becomes a sensitive technique to measure regional cerebral metabolism and detect subtle inflammatory changes in clinically symptomatic patients.

Aim

To Illustrate F-18 FDG PET/CT findings in clinically symptomatic patients with suspected encephalitis.

Materials and Methods

This is a series of three young patients who clinically presented with neurological signs and symptoms pointing towards paraneoplastic syndrome or suspected autoimmune encephalitis and were referred for whole body F-18 FDG PET/CT between 2024 and 2025 to rule out any oncological or infective etiology. Whole body F-18 FDG PET/CT scan was performed using standard SNM guidelines, Brain FDG PET/CT images were acquired using brain protocol and were further analyzed using Scenium neuroimaging software available on the multi-modality workstation. Both visual and semi-quantitative assessments were used to identify hypo- and hypermetabolic regions. The subcortical-to-cortical ratio was calculated by comparing the maximum standardized uptake values (SUVmax) of subcortical structures (basal ganglia, thalamus) with the cortical areas to evaluate relative glucose metabolism. Clinical histories, patient details, and PET/CT findings were systematically recorded and analyzed.

Results

Three male patients with a mean age of 23.7 ± 0.9 years were studied. All experienced behavioral changes and seizures; two had fever. MRI was normal in two cases, while CSF results were within normal limits for all. Antibody testing showed one Anti-NMDAR positive, one Anti-GAD positive, and one seronegative patient. Whole body (eye to thigh) FDG PET/CT was negative for any infective or neoplastic etiology but the Brain PET/CT images demonstrated global cortical hypometabolism in all patients. Significantly, all three had basal ganglia hypermetabolism, with subcortical-to-cortical metabolism ratios of 1.5, 1.6 and 1.8 respectively indicating active neuroinflammatory processes. All patients received immunotherapy (steroids alone or combined with IVIG or rituximab) and showed clinical improvement.

Conclusion

F-18 FDG PET/CT is a valuable diagnostic tool in suspected encephalitis, to rule out any neoplastic or infective cause, It demonstrates altered cerebral metabolism in early stages even when MRI and CSF findings are inconclusive. Early detection allows prompt immunotherapy, resulting in reduced morbidity, mortality and improved clinical outcomes.

ABAOCNMB222: Unmasking Paediatric Autoimmune Encephalitis: Diagnostic Utility of ¹⁸F-FDG-PET/CT in an MRI-Negative Case

Dr K Vidhya¹; *Dr Manishi L Narayan¹; Dr Rinkal¹; Dr Prateek Kumar Panda²; Dr Indar Kumar Shehrawat²

¹Dept of Nuclear Medicine, A.I.I.M.S, Rishikesh, ²Dept of Paediatrics, A.I.I.M.S, Rishikesh.

Introduction

Autoimmune encephalitis (AiE) is an immune-mediated CNS disorder presenting with seizures, abnormal body-movements, and neuropsychiatric features.¹ Paediatric cases often present with nonspecific symptoms, leading to delayed diagnosis. MRI may be inconclusive in about half cases, highlighting the importance of ¹⁸F-FDG PET/CT.²

Aim

To highlight the role of ¹⁸F-FDG-PET/CT in identifying characteristic metabolic-patterns suggestive of AiE in a paediatric patient, thereby aiding early-diagnosis and therapeutic decision-making.

Material and Methods

An 8-year-old female with acute febrile illness and refractory-seizures was evaluated. Clinical-details, laboratory-investigations, EEG/MRI, and ¹⁸F-FDG-PET/CT were analyzed. PET-imaging was performed 45-minutes after intravenous-administration of ~3 mCi of ¹⁸F-FDG using a dedicated-brain-protocol on a Biograph-mCT-64-TOF-PET/CT scanner-(Siemens).

Results

The child initially presented with fever, abdominal pain followed by recurrent generalized & focal seizures with alternating morphology, progressing to super-refractory status epilepticus. MRI was non-contributory. EEG demonstrated frequent epileptiform discharges with focal slowing over bilateral frontal and temporal regions, consistent with an epileptic encephalopathy. ¹⁸F-FDG-PET/CT revealed focal hypermetabolism in bilateral basal-ganglia and orbitofrontal cortices with diffuse hypometabolism in the remaining cerebral and cerebellar cortices, strongly suggestive of AiE.

AiE is a rare but treatable disorder, commonly associated with antibodies such as anti-NMDAR and LGI1, though the majority of paediatric cases may often be seronegative.³ Clinical presentations are heterogeneous, ranging from seizures and abnormal body movements to behavioral changes and autonomic instability.³ The gold standard for diagnosis is antibody detection in CSF, but this is limited by availability, variable sensitivity, and the invasive and time-consuming nature of the assays.¹ MRI, though widely used, may be normal in up to 50% of early AiE cases.⁴

¹⁸F-FDG-PET/CT offers unique advantages in such settings by detecting metabolic-alterations that precede structural changes.⁵ Characteristic-patterns include basal-ganglia hypermetabolism and diffuse cortical hypometabolism, as observed in our patient.⁶ It has also been shown to display varied-patterns of metabolism based on different antibody-positive cases of AiE.⁷ In cases of seronegative-AiE, PET is the only abnormal investigation, guiding early initiation of immunotherapy, as well as initiation of second-line immunosuppressives in patients not responding to first-line therapy.⁸ Furthermore, PET-imaging helps in establishing a baseline that can be used for aiding in assessing treatment-response and detecting relapses.⁹

Conclusion: ¹⁸F-FDG-PET/CT is invaluable in paediatric-AiE, especially when MRI is inconclusive. By identifying characteristic metabolic-patterns, PET enhances diagnostic-confidence and contributes to a more individualised-and-effective-management of AiE. Early integration of ¹⁸F-FDG-PET/CT into the diagnostic-pathway should be considered especially in cases of refractory paediatric-encephalitis to guide timely-and-targeted management.

ABAOCNMB052: Effect of antithyroid drug dose and duration on the Risk of Hypothyroidism after Radioiodine Therapy in Graves’ Disease

Khagesh Yadav, Shubham Goyal, K Vidhya, Vivek K Saini, Vandana K Dhingra

AIIMS Rishikesh

Introduction

Radioiodine therapy (RAI) is an established definitive treatment for Graves’ disease; however, post-therapy outcomes range from persistent hyperthyroidism to hypothyroidism. Antithyroid drugs (ATDs) are frequently used before RAI, but their dose and duration may influence treatment efficacy. Previous studies suggest that prolonged or high-dose ATD therapy, particularly when continued close to the time of RAI, may reduce ablation success and alter the likelihood of subsequent hypothyroidism. The impact of ATD exposure on thyroid outcomes after RAI therapy in Graves’ disease remains debated, particularly regarding dose and duration of Neomercazole (NMZ), warranting further evaluation.

Aim

To evaluate whether Neomercazole dose and duration prior to RAI are associated with post-RAI hypothyroidism.

Materials and Methods

We retrospectively analyzed Graves’ disease patients (from 2019 to 2024) treated with RAI after stopping Neomercazole for 5-7 days. Variables included age, neck swelling (goitre) status, neomercazole duration (years), pre-therapy daily dose (mg), RAI dose (mCi), and post-RAI hypothyroidism (yes/no). Univariate and multivariable logistic regression were used to estimate odds ratios (ORs) with 95% confidence intervals (CIs).

Results

Based on the inclusion and exclusion criteria, a total of 38 patients (32 females and 6 males) were included in the study. Variables included are summarized in following groups:

Post-RAI hypothyroidism occurred in 22/38 (57.9%). On univariate analysis, younger age was associated with higher odds of hypothyroidism (OR 0.95 per year; 95% CI 0.91–0.99; p≈0.02), while neck swelling, Neomercazole duration (OR ~1.01 per year; p≈0.92), and dose (OR ~0.99 per mg; p≈0.72) were not significant. RAI dose showed a borderline association (OR 1.19 per mCi; p≈0.06). In the multivariable model (age, gender, neck swelling, duration, dose, RAI dose), age (OR 0.94; 95% CI 0.89–0.99; p≈0.02) and RAI dose (OR 1.33; 95% CI 1.01–1.88; p≈0.04) independently predicted hypothyroidism, whereas neomercazole duration and dose did not (both p>0.2).

Conclusion

In this cohort, pre-RAI Neomercazole dose and duration were not associated with post-RAI hypothyroidism. Younger age and higher RAI dose were independent predictors of hypothyroidism. These findings suggest that, within typical dosing ranges, ATD exposure may not materially influence post-RAI thyroid failure risk, whereas patient age and RAI dosing merit attention during counseling and treatment planning. Larger, prospective cohorts data are warranted.

ABAOCNMB143: Synthesis and preliminary biological evaluation of an albumin binder conjugated [¹⁷⁷Lu]Lu-DOTA-TATE derivative for improved pharmacokinetics

Soumen Das, Rani G., Sheela M., Anupam Mathur, Usha Pandey

Radiopharmaceuticals Program, Board of Radiation and Isotope Technology (BRIT), Navi Mumbai

Introduction

[¹⁷⁷Lu]Lu-DOTA-TATE peptide receptor radionuclide therapy is a widely used therapeutic modality for the treatment of neuroendocrine tumors. However, the therapeutic efficacy is often limited by low tumor uptake due to the rapid clearance from the bloodstream, mainly through the kidneys which also makes it the dose limiting organ. To address these challenges, conjugation with an albumin binding moiety has been employed as a deliberate design strategy to improve the pharmacokinetics. Herein we report the synthesis and preliminary biological evaluation of such an albumin binder conjugated [¹⁷⁷Lu]Lu-DOTA-TATE derivative aimed to achieve an improved tumor-to-kidney uptake ratio.

Materials and Methods

The DOTA-TATE peptide derivative with 4-(p-Iodophenyl)butyric acid (pIBA) as an albumin-binder motif was synthesized following the standard fmoc strategy for solid phase peptide synthesis using 2-chlorotrityl chloride resin. Radiolabeling with ~50 mCi of [¹⁷⁷Lu]LuCl₃ (Specific activity: ~25 Ci/mg) was carried out by dissolving ~40 µg of the peptide in acetate buffer (pH 4.5) followed by heating in a boiling water bath for 45 min. Affinity of the ¹⁷⁷Lu-labeled peptide derivative towards human somatostatin receptor 2 (SSTR2) was evaluated by performing in vitro cell uptake studies in AR42J cell line taking different time points (1, 4, 24, and 48 h). Specificity of uptake was ascertained by performing receptor blocking studies with excess inactive DOTA-TATE. The same set of studies were also performed with in-house prepared [¹⁷⁷Lu]Lu-DOTA-TATE.

Results

The peptide derivative was synthesized with an overall yield of ~25%. The ¹⁷⁷Lu-labeled peptide was obtained in high radiochemical purity (>98%) as ascertained by radio-TLC and radio-HPLC. The radiotracer exhibited significantly high initial in vitro cell uptake of ~10% at 4 h incubation which was similar to that of [¹⁷⁷Lu]Lu-DOTA-TATE (~15%) at the same time point. Maximum cell uptake of ~22% was observed for the synthesized peptide at 48 h in comparison to ~35% for [¹⁷⁷Lu]Lu-DOTA-TATE. These uptakes were also found to be highly specific to the extent of ~90-95% for both the synthesized radiotracer as well as [¹⁷⁷Lu]Lu-DOTA-TATE at the selected time points as 1 h pre-incubation with excess inactive DOTA-TATE peptide could reduce the cell uptake of the radiotracers to <10%.

Conclusions

A [¹⁷⁷Lu]Lu-DOTA-TATE derivative with pIBA as an albumin binder for improved pharmacokinetics was successfully synthesized. The radiotracer also fared well in comparison to [¹⁷⁷Lu]Lu-DOTA-TATE in in vitro cell uptake studies. However, biodistribution study in tumor xenograft is required to understand the true therapeutic efficacy of the radiotracer.

ABAOCNMB272: Addition of 177Lu-PSMA-617 in the treatment of hormone sensitive metastatic prostate cancer: a prospective pilot study

Vignesh H, Nandini Pandit, Smita Kayal, Kannan P

JIPMER

Introduction

Prostate cancer is one of the leading causes of cancer-related deaths and currently the second most common male malignancy worldwide. Numerous treatment options have been added to the treatment of metastatic prostate cancer in the past decades, including docetaxel, androgen receptor directed therapy and novel modalities such as radioligand therapy and PARP inhibitors. Lu-177 PSMA radioligand therapy (PSMA-RLT) is traditionally employed after exhausting other lines of treatment. It is now being introduced in earlier time-points of metastatic prostate cancer. We present the results of application of Lu-177 PSMA at a lower therapeutic dose, in metastatic hormone sensitive prostate cancer (mhsPC) patients alongside Androgen Deprivation Therapy (ADT) and Abiraterone.

Materials and Methods

mhsPC patients on androgen deprivation therapy (ADT) who cannot tolerate docetaxel were included. After biopsy and metastatic evaluation with Ga-68 PSMA PET/CT, and initiation of ADT, patients received 2 cycles of Lu-PSMA 617 (100mCi per cycle) in addition to Abiraterone which was continued. Serial serum PSA values and FACT-P scores were obtained.

Results

All of the 9 patients recruited showed sustained PSMA response 6 months post initiation of therapy. Notably, post therapy scans of 2 patients showed complete response. 6 out of 9 patients showed an increase in FACT-P scores, with most patients showing improvement in physical and emotional well being followed by functional well being.

Conclusion

We aim to demonstrate the use of PSMA-RLT at an earlier time point in the disease course, to achieve better quality of life by delaying the need for chemotherapy. High PSMA expression in this newly treated/treatment naive cohort is a welcome advantage. Clinical and biochemical responses were noted with a lower dose of Lu-177 PSMA, which is another interesting area of exploration. This pilot study encourages research on optimal sequencing, combination therapy and dose equivalence trials, in line with ongoing global trials experimenting the earlier use of PSMA-RLT.

ABAOCNMB195: EARLY EFFECTS OF 177LU-PSMA RADIOLIGAND THERAPY ON RENAL FUNCTION: A PROSPECTIVE OBSERVATIONAL STUDY

Aftab Hasan Nazar, Rajvir Mehra, P K Pradhan, Manish Ora, Sukanta Barai, Amitabh Arya

Sanjay Gandhi Post Graduate Institute of Medical Sciences

Aim/Introduction

This study aimed to evaluate the early effects of 177Lu-PSMA radioligand therapy (RLT) on renal function by analyzing serum creatinine changes occurring within one week after therapy administration in patients with metastatic castration-resistant prostate cancer (mCRPC).

Materials and Methods

A prospective observational study was conducted on 15 mCRPC patients who underwent 177Lu-PSMA RLT. Thirteen patients completed 6 cycles of therapy, while two patients completed 5 cycles, resulting in a total of 88 treatment cycles for analysis. Serum creatinine levels were measured immediately before and one week after each therapy cycle. Changes in creatinine levels were categorized by direction (increase, decrease, or unchanged) and clinical significance (defined as changes >0.3 mg/dL). Statistical analysis included calculation of means, medians, ranges, and standard deviations, with significance set at p<0.05.

Results

Mean pre-therapy serum creatinine was 1.09 mg/dL (range: 0.60-1.87 mg/dL), while mean post-therapy value was 1.10 mg/dL (range: 0.60-1.70 mg/dL). The mean difference between pre- and post-therapy measurements was 0.01 mg/dL, which was not statistically significant (p>0.05). Of the 88 treatment cycles, 47.7% (n=42) showed increases in creatinine values, 44.3% (n=39) showed decreases, and 8.0% (n=7) showed no change. Only 7.9% of all treatments resulted in clinically significant creatinine changes (>0.3 mg/dL) - with 3.4% (n=3) showing significant increases and 4.5% (n=4) showing significant decreases. Analysis across consecutive treatment cycles revealed no consistent pattern of creatinine changes, with similar distributions of increases and decreases observed throughout the treatment course.

Conclusion

177Lu-PSMA radioligand therapy does not appear to cause immediate clinically significant nephrotoxicity as measured by serum creatinine in the majority of treatment cycles. The bidirectional nature of the observed changes, with nearly equal proportions of increases and decreases, suggests that factors other than direct nephrotoxicity may influence short-term creatinine fluctuations in this patient population. These findings support the renal safety profile of 177Lu-PSMA RLT in the immediate post-treatment period, though longer-term studies are warranted to assess potential cumulative effects.

Supplement

1. Overall Creatinine Statistics

2. Direction of Creatinine Change

3. Clinically Significant Changes

ABAOCNMB144: Development of a lyophilized kit for the preparation of therapy doses of [¹⁷⁷Lu]Lu-labeled RGD peptide dimer: a strategy for enhanced clinical access

Soumen Das¹, Priyalata Shetty², K. V. Vimalnath², Usha Pandey¹, Sudipta Chakraborty²

¹Radiopharmaceuticals Program, Board of Radiation and Isotope Technology (BRIT), Navi Mumbai - 400703, India, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai - 400085, India

Introduction

Integrin α_vβ₃ receptors are highly overexpressed in various malignancies and are an attractive target for theranostic applications. Dimeric cyclic RGD peptides have been well-documented in this regard as a reliable vector for such malignancies in view of their superior tumor-to-non-target uptake property. Lutetium-177, on the other hand, has attracted a lot of interest in various forms of targeted therapy. However, on-site radiolabeling of molecular vectors with ¹⁷⁷Lu, although effective, can be challenging for many nuclear medicine departments as it requires extensive on-site synthesis and quality control. Therefore, to facilitate wider adoption, a single-vial lyophilized kit was developed and validated for efficient and reproducible preparation of [¹⁷⁷Lu]Lu-DOTA-E[c(RGDfK)]₂ for routine clinical application in hospital radiopharmacies.

Materials and Methods

Lyophilized kits were formulated under aseptic condition in a Class 100 (ISO 5) clean room facility. 164 mg of sodium acetate was dissolved in 16 mL of ultrapure water. To this solution, 100 mg gentisic acid was added followed by the addition of 4 mg DOTA-E[c(RGDfK)]₂ peptide separately dissolved in 4 mL ultrapure water. This stock solution (20 mL) was then filtered through a 0.22 μ filter and 1 mL each was dispensed in 10 mL glass vials and lyophilized for 24 hours. For the preparation of [¹⁷⁷Lu]Lu-DOTA-E[c(RGDfK)]₂ clinical doses (~7.4 GBq), the contents of the kit vial were dissolved in 1 mL of MilliQ water and [¹⁷⁷Lu]LuCl₃ (Specific activity ~25 mCi/mg) were added into it. The mixture was stirred thoroughly and incubated for 30 min at 90°C. Pre-clinical biological evaluation was performed in C57BL/6 mice bearing melanoma tumors. Preliminary clinical investigations were carried out in locally advanced breast cancer patients.

Results

The developed lyophilized kit formulation consistently yielded the radiolabeled product with high radiochemical purity (97.5 ± 0.4%) and high specific activity (40 ± 2 MBq/µg of peptide). Biodistribution studies showed rapid tumor uptake with fast clearance from the non-target organs. In a patient administered with ~7.4 GBq dose of [¹⁷⁷Lu]Lu-DOTA-E[c(RGDfK)]₂, intense radiotracer uptake was observed in the breast cancer lesion with insignificant uptake in any other major non-target organs. The developed kit also demonstrated excellent stability when stored at 0^oC for at least six months.

Conclusions

The developed lyophilized kit for the preparation of [¹⁷⁷Lu]Lu-DOTA-E[c(RGDfK)]₂ demonstrate a robust and practical solution to streamline clinical translation of the radiopharmaceutical and expand the accessibility of targeted radionuclide therapy to a broader range of clinical centers, ultimately improving patient care.

ABAOCNMB211: Evaluation of In-Vitro stability of therapeutic ¹³¹I-mIBG supra dose by chromatography method.

Sarika D Paunikar (1,3), Pooja Dwivedi (1,3), Dibya Prakash (1,3), Manoj Kumar Chauhan (1,3), Vishal Vajarkar (1,3,), Sunit Mitra (1,3), Archi Agarwal (1,2,3).

¹Department of Nuclear Medicine and Molecular Imaging, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, India, ²Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital (TMH), Tata Memorial Centre, Mumbai, India, ³Homi Bhabha National Institute (HBNI), Mumbai, India.

Abstract

Introduction: The radiopharmaceutical ¹³¹I-mIBG (Iodine-131 Meta-Iodobenzylguanidine) has emerged as a critical therapeutic agent for neuroendocrine tumors, including neuroblastoma and pheochromocytomas. However, the stability of supra doses (high concentrations) of this radiopharmaceutical remains underexplored. This study aims to evaluate the in vitro stability of supra dose ¹³¹I-mIBG under ambient room temperature vs -18⁰ C temperature. Results reveal that supra doses of ¹³¹I-mIBG exhibit significant stability in refrigerated condition but showed degradative patterns in prolonged exposure to room temperature. These findings have implications for optimizing the storage of Supra dose ¹³¹I-mIBG.

¹³¹I-mIBG (Iodine-131 labeled Meta-Iodobenzylguanidine) is a norepinephrine analog that selectively targets adrenergic tissues. Its therapeutic use in patients with neuroblastoma and other neuroendocrine tumors has demonstrated significant efficacy. However, as the need for high-dose radiopharmaceutical therapies increases, understanding the stability of supra doses becomes essential to ensure both safety and efficacy.

The In-Vitro stability of radiopharmaceuticals depends on several factors, such as specific activity of ¹³¹I, concentration of mIBG used, chemical degradation and radiolysis which affects the radiochemical Purity, shelf life and efficacy of the final product. High doses of ¹³¹I-mIBG increase the risk of radiolysis due to the higher radiation emitted per volume.

Aim and Objective: As the need for high-dose radiopharmaceutical therapies increases, understanding the stability of supra doses becomes essential to ensure both safety and efficacy. This study seeks to evaluate the stability of supra dose ¹³¹I-mIBG under controlled condition and to optimize the storage condition for longer shelf life and efficacy of supra dose ¹³¹I-mIBG.

Materials and Methods: Therapeutic Supra dose of ¹³¹I-mIBG was received from BRIT (Board of Radiation and Isotope Technology) with packaging note of having Specific Activity of 460mCi/mg, cold mIBG content has been used for the labelling procedure is 33ug/ml. Final volume received is 64 ml devided in 8vials (8ml/vial). So total cold mIBG used is 2.112 mg for the labelling procedure of around 800 mCi ¹³¹I and hence mIBG content used is 2.64ug/mCi. In other way, from different consignment of non-supra dose formulation showed specific activity is in range of 42-146.5 mCi/mg and cold mIBG content was used 7.8-34.5ug/mCi for the labelling. After labelling, cold mIBG in final product acts as radioprotectant, but having cold mIBG in final formulation may affect the specific uptake of ¹³¹I-mIBG.

For the evaluation of stability of Supra dose ¹³¹I-mIBG, one set has been stored at -8⁰C and second set kept at room temperature (19⁰C to 25⁰C). Radio Chemical Purity has been performed with Instant Thin layer Chromatography (ITLC) and Paper Chromatography. In this procedure two types of mobile phase have been used 0.1M sodium citrate buffer at pH 4-5 and 3:1:1 (Chloroform: Methanol: Acetic acid) solvent. ITLC-SG aluminum backing strip and Whatman paper no.3 (WMP3) has been used as stationary phase. Different solvent and different stationary phase has used to get one good chromatography method with less hazardous and less volatile mobile and stationary phase combination which resolve product and impurity peak easily.

Results: Samples stored at -8°C retained 98% of their radiochemical purity after 48 hours till 6 days it shows >95% RCP.

At room temperature (19⁰C - 25°C), a % reduction in RCP was observed after 24 hours, it showed 89% RCP at 24 hr.

All combination of mobile phase and stationary phases showed similar %RCP, means all combination are reliable.

But 0.1 M sod. Citrate buffer and ITLC-SG showed good resolution with Rf of ¹³¹I-mIBG is at 0.2 and Rf of free ¹³¹I is at 0.7.

Conclusion and Discussion: The findings indicate that supra dose ¹³¹I-mIBG is highly stable under low-temperature conditions, which aligns with standard storage recommendations. However, degradation of supra dose has been seen at room temperature environments highlights the need for careful handling and storage, particularly in clinical settings where delays in administration may occur.

ABAOCNMB256: Comparative Evaluation of Early and Standard Acquisition Time Points in 18F-FDG PET/CT for Malignant Lesions: A Quantitative Agreement Study

Dr Vishal Jain,*Dr Manishi L Narayan*, Dr Vivek K Saini, Dr Rinkal Shah, Dr Deeksha Chaudhary, Dr Chandrakanth Puranicmath, Dr Subin S, Dr Ajith SK.

*Corresponding author : Dr Manishi L Narayan, Dept of Nuclear medicine, AIIMS Rishikesh All India Institute of Medical Sciences, Rishikesh

Introduction and Aims

Positron emission tomography/computed tomography (PET/CT) using 18F-fluorodeoxyglucose (FDG) is a cornerstone in oncologic imaging, with standard acquisitions performed 60 minutes post-injection. However, early imaging may improve patient throughput and comfort if quantitative agreement with standard scans is maintained. The present study aimed to compare semi-quantitative PET parameters at 30-55-minute acquisitions with standard PET acquisition post 60-minutes, assessing reproducibility and agreement of SUVmax, MTV, and TLG values.

Materials and Methods

Thirty patients (mean age 54.8 years; 20 females, 10 males) with histologically confirmed malignancies underwent dynamic and static 18F-FDG PET/CT imaging. Lesion-wise SUVmax, SUVmean, metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were derived at 30, 45, and 55 minutes and compared with standard PET. Data were analysed using SPSS. Normality was assessed using the Shapiro–Wilk test. As the data were non-normally distributed, the Friedman test was applied to assess overall differences, followed by Durbin–Conover pairwise comparisons with Holm adjustment for multiple testing. p < 0.05 was considered statistically significant.

Results

Mean SUVmax values progressively increased with time: 11.41 ± 5.1 at 30 minutes, 13.0 ± 6.23 at 45 minutes, 14.59 ± 7.1 at 60 minutes, and 16.99 ± 8.7 in standard PET.

The non-parametric repeated-measures ANOVA (Friedman test) showed a highly significant difference in SUVmax across all four acquisition time points (χ² = 63.9, df = 3, p < 0.001). Post-hoc Durbin–Conover pairwise comparisons confirmed that SUVmax increased significantly between every consecutive time point (all p < 0.001), demonstrating progressive tracer accumulation from 30 to 60 minutes and peaking in the standard PET acquisition.

For MTV, the Friedman test also revealed a significant difference (χ² = 25.4, p < 0.001). Post-hoc analysis showed that MTV values changed between 30 and later time points, stabilising beyond 45 minutes.

Similarly, TLG values differed significantly across acquisitions (χ² = 40.6, p < 0.001), with Durbin–Conover tests showing a consistent increase from 30 minutes to standard PET acquisition after 60 minutes (all p < 0.01).

Conclusion

Dynamic PET/CT imaging revealed time-dependent changes in quantitative FDG metrics. SUVmax and TLG demonstrated significant progressive increases, while MTV stabilised after 45 minutes. These findings suggest that early (45-minute) acquisitions provide reliable quantitative data with good concordance to standard imaging protocol post 60-minutes of injection, supporting the potential clinical feasibility of early acquisition protocols.

ABAOCNMB189: 18F-FDG PET/CT in TENIS: The Tg Cut-off That Predicts Positivity

Manish Ora, Aftab Hasan Nazar, Amitabh Arya, Sukanta Barai, Prasanta Kumar Pradhan

SGPGIMS

Background

Thyroglobulin-elevated negative iodine scintigraphy (TENIS) represents a challenging clinical scenario in well-differentiated thyroid cancer, where tumor marker (S Thyroglobulin, Tg) level is not corroborated by whole-body radioiodine imaging. 18F-FDG PET/CT is a valuable imaging modality for identifying residual or recurrent disease and guiding further management. However, studies have shown variable performance of PET/CT in these settings. This study aims to determine the performance of FDG PET/CT in TENIS patients in Indian cohorts.

Methods

A retrospective cohort of 137 TENIS patients (mean age 41.5 ± 15.5 years; male-to-female ratio ~ 60:40) was analyzed. The common HPE were PCT 79.6% and FDC (6.6%). Central and lateral lymph node dissection was performed in 70.1% and 32.1% of patients, with HPE demonstrating metastasis in 60.6% and 26.3%, respectively. Clinical and pathological variables were systematically categorized. FDG PET/CT scans were classified as positive or negative, and the sites of recurrence or metastases were documented. Lung nodules that were multiple, well-defined, randomly distributed, with or without FDG uptake, were considered metastatic. ROC analysis determined the discriminative ability of Tg for predicting PET positivity, with AUC and optimal threshold identified using Youden’s index.

Results

Serum Tg levels at the time of PET/CT were 123.8 ± 108.1 ng/mL, Median: 73.2 (Q1: 42.2, Q3: 225.0). PET positivity was observed in 75.9% patients, most commonly in the neck (43.8%), followed by lung (11.7%) and bone (10.2%). The mean Tg was significantly higher in PET-positive patients compared to those with PET-negative results (p < 0.05). ROC analysis yielded an AUC of 0.685, indicating moderate discriminatory ability. The optimal Tg threshold for predicting PET positivity was 52.8 ng/mL, providing 80.7% sensitivity and 56.3% specificity.

Conclusion

18F-FDG PET/CT demonstrates high sensitivity and moderate specificity in TENIS patients. Tg levels, while moderately predictive, achieve optimal discriminative power at ~53 ng/mL, above which PET positivity becomes substantially more likely. This study provides an evidence-based threshold that informs patient selection and optimizes resource allocation.

ABAOCNMB202: 18 F FDG PET CT SCAN IN DIAGNOSING GYNAECOLOGICAL CAUSE OF NEUROLOGIC CONDITION- A CASE REPORT OF ANTI NMDA RECEPTOR ANTIBODY POSITIVE ENCEPHALITIS IN OVARIAN TERATOMA

Madangopal Vishnoi, Braj Kishore Singh, Dharmesh Paliwal, Anurag Jain, Rajeev Kumar, Kartikey P Solank

ARMY HOSPITAL (R&R) DELHI CANTT, NEW DELHI

Introduction

Autoimmune encephalitis represents a group of inflammatory brain disorders mediated by autoantibodies targeting neuronal surface or synaptic proteins. Among these, anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, involving antibodies against the GluN1 subunit, is one of the most frequent. It primarily affects young females of reproductive age, presenting with a spectrum of neuropsychiatric manifestations such as behavioural changes, seizures, and dyskinesias. A substantial proportion of cases—up to 38%—are associated with ovarian or extra-ovarian teratomas that express neuronal antigens, thereby triggering autoimmune activation. Early identification and management are critical for favourable neurological outcomes.

Material and Method

We report the case of a 35-year-old female who presented with fever, neuropsychiatric symptoms, and progressive behavioural disturbances. Neurological assessment, cerebrospinal fluid (CSF) analysis for anti-NMDAR antibodies, and neuroimaging were performed. Brain MRI showed no abnormalities, while 18F-fluorodeoxyglucose positron emission tomography–computed tomography (18F-FDG PET-CT) was used to identify potential paraneoplastic associations. The patient received immunotherapy, followed by surgical management upon detection of a pelvic lesion.

Result

CSF testing confirmed positivity for anti-NMDAR antibodies, establishing the diagnosis of autoimmune encephalitis. PET-CT imaging revealed characteristic metabolic patterns consistent with neuroinflammatory disease—midbrain hypermetabolism with symmetrical thalamic hypometabolism and occipital cortical hypometabolism. Additionally, the study identified a heterogeneously FDG-avid, calcified, mixed-density lesion in the right adnexa, suggestive of an ovarian teratoma. The patient was managed with intravenous immunoglobulin and corticosteroids, followed by teratoma resection. Post-treatment, she displayed marked clinical improvement, correlating with observed recovery trends in patients undergoing combined immunotherapy and surgical tumor removal.

Conclusion

Anti-NMDAR encephalitis should be a key differential diagnosis in young women presenting with acute psychiatric or neurological decline, particularly when initial neuroimaging is inconclusive. This case highlights the crucial diagnostic role of advanced metabolic imaging, such as 18F-FDG PET-CT, in identifying both central inflammatory patterns and underlying paraneoplastic sources. Early integration of immunotherapy with timely tumor excision leads to significant neurological recovery and improved long-term prognosis. Recognition of this autoimmune–paraneoplastic interplay reinforces the importance of multidisciplinary evaluation in ensuring favourable outcomes for patients with anti-NMDAR encephalitis secondary to ovarian teratoma.

ABAOCNMB197: Diagnostic utility of F-18 FDG PET/CT in the staging of Incidental Gallbladder Cancer - A systemic review and meta-analysis.

Deepanksha Datta, Selvakumar B, Akhil Dhanesh Goel, Peeyush Varshney, Muruggappan

All India Institute of Medical Sciences

Objectives

This study aims to evaluate the accuracy of F-18 FDG PET/CT in the staging of incidentally detected gallbladder cancer (iGBC) in terms of detection of local residual disease, lymph nodal or distant metastases after the initial cholecystectomy.

Methods

A systematic search was done using databases in PubMed, Scopus, and Cochrane Library - supplemented by Google Scholar - by two independent authors. The studies that reported the findings of F-18 FDG PET/CT in post cholecystectomy patients with pathologically confirmed iGBC, were only included in this review and analysis. After assessing each included study for the risk of bias and publication bias, the accuracy of F-'18 FDG PET/CT in detecting the residual and metastatic disease (both nodal and distant) was calculated.

Results

Three studies were included in the review, comprising of a total of 157 patients – 75% were females, most common type being adenocarcinoma and T2 stage. The time interval between the initial surgery and PET/CT scan was 2-52 weeks. The pooled sensitivity and specificity of F-18 FDG PET/CT positivity in detecting any residual disease in iGBC were 73% (95% confidence interval, CI 60 – 84%) and 71% (95% CI – 60 – 81%) respectively with a diagnostic Odd’s ratio of 10.3 (95% CI – 1.5 to 69.2) and an AUC of 0.779 on SROC analysis.

Conclusion

F-18 FDG PET/CT has a decent accuracy to predict residual disease in iGBC. However further prospective studies are warranted to establish the utility of F-18 FDG PET/CT in altering management decisions in iGBC in the real-world scenario.

(Funding: None; PROSPERO: CRD42024498658)

ABAOCNMB155: Revolutionizing Malignant Melanoma Management: ¹⁸F FDG PET CT as a Diagnostic and Prognostic Tool

Adersh Stanly¹, Julie Hephzibah¹, Saumya Sunny¹, Justin Benjamin¹, Junita John¹

¹Department of Nuclear Medicine, Christian Medical College Vellore.

Introduction

Melanoma is a malignancy involving the transformation of melanocytes, originating from the neural crest and developing in various organs. Early detection is crucial for effective treatment. However, malignant melanoma often occurs in distant organs, making regional imaging ineffective. This study aims to explore the role of ¹⁸F FDG PET CT in malignant melanoma imaging and its growing importance in diagnosis and management.

Aim

To explore the role of ¹⁸F FDG PET CT in the diagnosis, staging, and management of malignant melanoma.

Methods

Retrospective analysis of patients who underwent ¹⁸F FDG PET CT scans between January 2023 and April 2024, following suspicion or diagnosis of malignant melanoma.

Results

20 patients with a mean age of 50.7 years were included. 19 out of 20 patients underwent surgery to the primary lesion, with 9 patients underwent surgery elsewhere. Out of these patients, 18 had biopsy evidence confirming the lesion as malignant melanoma. 15 patients had uptake in the primary site, which could be primary lesion, residual, or recurrence. Osseous metastases were noted in 2 patients, and inguinal/para-iliac/ abdominal nodal metastases in 10 patients, intra-abdominal metastases in 3 patients, lung metastases in 3 patients, mediastinal/hilar nodal metastases in 4 patients, and muscle uptake in 4 patients.

¹⁸F FDG PET CT upstaged disease in 12 patients. Among these 2 patients lost to follow-up. The remaining patients received chemotherapy + radiotherapy. 12 patients had follow-up PET CT scans. 6 patients showed complete resolution, 3 had partial response, and 3 patients had disease progression, leading to a change in management. A second follow-up PET CT was done in 8 patients, with 5 patients continuing to have complete resolution. The study also found a correlation between SUVmax and Breslows thickness, suggesting that SUVmax increases as Breslows thickness increases.

Conclusion

Our study highlights the importance of ¹⁸F FDG PET CT in the staging and management of malignant melanoma. It provides valuable insights into disease spread, monitors treatment response, and detects recurrence. It also plays a crucial role in post-treatment surveillance, enabling timely intervention. Overall, ¹⁸F FDG PET CT is a critical imaging technique in the comprehensive management of malignant melanoma, contributing to improved patient outcomes.

ABAOCNMB099: Imaging meets cytology: correlation of FDG PET/CT, USG and cytology in evaluation of thyroid incidentalomas – institutional cohort study

Mages Saravanen, Indirani Muthukrishnan, Dinesh Kumar Gauthaman, Valaiyapathy Chinna, Shelley Simon

Apollo hospitals, Greams road

Introduction

Thyroid incidentalomas, defined as clinically unidentified thyroid lesions identified by imaging performed for non-thyroidal diseases, have become increasingly detected with the widespread use of advanced imaging modalities such as 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) (1)(5). In oncologic and general health screening populations, the prevalence of thyroid incidentalomas identified on FDG PET/CT is reported to be approximately 1–4%, with significant proportion of them exhibiting focal FDG uptake[4][5]. These lesions have relatively high risk of malignancy compared to thyroid nodules detected by other imaging techniques as focal FDG uptake denotes increased cellularity in the thyroid nodule, with reported malignancy rates reaching up to 35–40% in some studies (4)(5).

Assessment of these incidentalomas required a multimodal approach. Ultrasound (USG) serves as a sensitive tool for further anatomical characterization, while USG guided fine-needle aspiration cytology (FNAC) provides cytological evaluation to differentiate benign from malignant pathology based on thyroid imaging and data system (TIRADS) scoring (1)(2). Biochemical markers, including serum thyroglobulin (TG) and thyroid-stimulating hormone (TSH), add valuable information regarding functional status and potential malignancy risk. A systematic institutional analysis, correlating FDG PET/CT findings with USG features, FNAC results, and biochemical profiles, is essential to refine risk stratification and optimize clinical management strategies for these patients (2)(6).

Aim: To evaluate the prevalence of malignant lesions among thyroid incidentalomas detected in FDG PET/CT and correlation of imaging parameters with cytology findings.

Materials and Methods

This retrospective study included 163 patients (52 M; 111 F) with age ranging from30 to 85 yrs (mean age – 58 years) who underwent F18-FDG PET/CT from Jan 2017 to Aug 2025 for non-thyroidal indications and were identified to have thyroid incidentalomas. Patient’s clinical and demographic data were collected. Indication for PET/CT, FDG uptake pattern and maximum standardized uptake value (SUVmax) were collected from PET/CT report. Anatomical characteristics were collected from USG Neck – size and TIRADS scoring. FNAC reports were collected for patients who underwent FNAC, which was reported according to Bethesda system for reporting thyroid cytology.

Data analyzed to assess correlations between PET/CT findings, USG features, FNAC results, and biochemical parameters. Statistical analysis included descriptive statistics, and tests for association between imaging, cytological, and biochemical findings. Malignancy rates were calculated for different categories.

Result: Among the 163 patients with thyroid incidentalomas detected in FDG/PET/CT, 33 patients (20.2 %) had malignant lesions. There is significant association between SUVmax and TIRADS category —higher TIRADS correlates with higher SUVmax and highly significant association—malignant Bethesda grades show higher SUVmax; mean SUVmax of malignant lesions – 11 whereas mean SUVmax of non-malignant lesions were 3.5. Thyroid incidentalomas with SUVmax < 6 were more likely to be benign. Very strong association between TIRADS and Bethesda category is observed - higher TIRADS is much more likely malignant by FNAC.

Conclusion: The institutional prevalence of malignant lesions among FDG PET/CT-detected incidentalomas is 20.2%, which is notably lower than the standard prevalence reported in the literature (30–35%). Higher TIRADS and SUVmax are associated with malignant cytology (Bethesda 5/6). Thyroid incidentalomas with higher SUVmax (>6) and TIRADS score >3 warrants FNAC as malignancy risk of incidentalomas raises as TIRADS score increases.

ABAOCNMB265: “PAROTID LYMPHOMA: A RARE PRESENTATION OF HODGKIN LYMPHOMA EVALUATED WITH 18F-FDG PET/CTâ€

Ayan Dhiman, Roshan Karna, Raman Manojkumar Toshniwal, Sulochana Saraswat, Kalpa Jyoti Das, Abhinav Singhal

AIIMS

Introduction

Lymphomas of the salivary glands are rare, comprising less than 5% of all extranodal lymphomas and under 1% of salivary gland neoplasms. Among these, the parotid gland is the most frequently affected. While non-Hodgkin variants, particularly mucosa-associated lymphoid tissue (MALT) lymphomas, predominate, Hodgkin lymphoma (HL) involving the parotid gland remains exceedingly uncommon. Because its clinical presentation mimics benign or inflammatory parotid lesions, diagnosis can be challenging. ^18F-fluorodeoxyglucose positron emission tomography/computed tomography (^18F-FDG PET/CT) has become pivotal for accurate staging, disease characterization, and therapy planning in HL.

Case Presentation

A 39-year-old male presented with a gradually enlarging right parotid and submandibular swelling over one year. There was no significant medical history. Fine-needle aspiration cytology from the parotid and cervical nodes revealed atypical lymphoid cells and Reed–Sternberg–like cells suggestive of Hodgkin lymphoma. Baseline ^18F-FDG PET/CT demonstrated intensely increased FDG uptake in the right parotid gland and ipsilateral cervical lymph nodes, without evidence of systemic disease or distant metastases. The patient was thus staged as having localized Hodgkin lymphoma involving the right parotid and cervical nodes. The PET/CT findings guided biopsy confirmation and subsequent management planning.

Discussion

Primary or secondary parotid gland involvement by HL is exceptionally rare, often leading to diagnostic confusion with more common benign parotid tumors. PET/CT imaging offers superior diagnostic sensitivity and specificity compared with conventional CT, enabling precise delineation of both nodal and extranodal disease sites. It serves as the imaging cornerstone in the Lugano classification system for staging and in standardized response assessment through the Deauville five-point scale. In this case, PET/CT was instrumental in confirming localized disease, excluding disseminated involvement, and aiding in biopsy site selection. Early identification of disease extent allowed prompt initiation of appropriate therapy, thereby improving prognostic accuracy and therapeutic outcomes.

Conclusion

This case underscores the critical role of ^18F-FDG PET/CT in evaluating atypical nodal presentations such as parotid gland involvement in Hodgkin lymphoma. Awareness of this rare manifestation is essential for nuclear medicine physicians to avoid misinterpretation and ensure timely, accurate staging. PET/CT not only defines the anatomical and metabolic disease extent but also guides management decisions, reinforcing its indispensable value in lymphoma care.

ABAOCNMB245: Role of FDG PET-CECT in the Detection of Portal Vein Tumor Thrombi Caused by Both Hematogenous Spread and Direct Infiltration by Hepatic Metastasis in a Case of Gastric Adenocarcinoma

Gowri Sankar, Anindya Halder, Arindam Chaudhury, B Vinesh

All India Institute of Medical Sciences (AIIMS), Kalyani

Introduction

Gastric carcinoma is one of the most lethal malignancies with a five-year survival rate of ~ 20% [1]. Portal vein tumor thrombus (PVTT) originating from gastric adenocarcinoma is very rare, and is seen in ~ 1% of the cases, according to one autopsy study done in Japan [2]. Increased FDG uptake can differentiate tumour thrombus from bland thrombus [3].

Case Report

A 61-year-old male patient presented with complaints of difficulty in swallowing solid foods for 4 months, cough with reflux of food particles, and significant weight loss. UGI scopy revealed ulcero-nodular growth at the gastro-oesophagal (GE) junction, with biopsy revealing moderately differentiated adenocarcinoma.

PET-CECT scan findings revealed metabolically active asymmetric circumferential mural thickening in the GE junction, cardia, fundus and proximal body of the stomach along the lesser curvature with SUV Max of 8.8, corresponding with the primary lesion. Metabolically active and non-active heterogeneously enhancing multiple lymph nodal metastases involving the perigastric, peri-pancreatic, periportal, aortocaval, para-aortic and retrocaval groups.

Metabolically active heterogeneously enhancing tumour thrombus was noted in the main portal vein (MPV), with SUV Max of 4.48. Non-avid bland thrombus was seen extending proximal to the tumour thrombus, up to the confluence of the right and left portal vein and extending into the left portal vein branch.

Scan also revealed a metabolically active heterogeneously enhancing metastatic deposit in segment V/VI of the liver involving/infiltrating the adjacent right portal vein, leading to tumour thrombus with SUV Max of 4.3. Final TNM staging was T4aN3aM1. Multidisciplinary tumour board opted for palliative chemotherapy once his nutrition improved.

Discussion

Oh SD et al mentioned PVTT in gastric cancer is due to a hypercoagulable state, compression of MPV by enlarged metastatic lymph nodes and through increased expression of intercellular adhesion molecule 1 (ICAM-1) by gastric adenocarcinoma cells [11]. PVTT in the MPV, in our case, was likely formed due to hematogenous spread from the primary site through smaller gastric veins and compression of the MPV by enlarged regional metastatic lymph nodes. Whereas the tumor thrombus in the right portal vein branch was due to direct infiltration from the liver metastasis.

The bland thrombus proximal showed no FDG uptake. Thus, FDG PET could differentiate between malignant and bland thrombi in gastric adenocarcinoma, similar to those in HCC.

Conclusion

PVTT in gastric adenocarcinoma is rare and can be due to a hypercoagulable state along with hematogenous spread or due to direct infiltration from hepatic metastases. We reported a case of gastric carcinoma with PVTT, detected by FDG PET-CECT, showing both these modes of formation of tumor thrombus. PVTT presence in gastric cancer can lead to a change in the management and represents a poorer prognosis.

ABAOCNMB208: THE SPECTRUM OF SKEL ETAL AND EXTRASKELETAL INVOLVMENT OF LANGERHANS CELL HISTIOCYTOSIS ON F-18 FDG PET/CT SCAN.

Shaik Rishma, Tekchand Kalawat, Ramya Priya R

SRI VENKATESHWARA INSTITUTE OF MEDICAL SCIENCES

Introduction

Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder where langerin-positive cells coalesce as granulomatous lesions and deposit in various tissues throughout the body as inflammatory infiltrates, it is classified into single-system LCH (sLCH) with multifocal or unifocal involvement and multisystem LCH (mLCH).

Aim

To evaluate the different patterns of LCH and involvement of risk organs for staging and response evaluation using F-18 FDG PET/CT imaging.

Material and Methods

This retrospective study included a total (n=9) recently diagnosed and treated LCH patients with histopathological confirmation who underwent F-18 FDG PET/CT from January 2010 to June 2025. The Study performed in Euglycemic hypoinsulinemic state after overnight fasting after injection of F-18 FDG PET/CT.

Results

The mean age of study population is 24.5 ± 13.7; 5 men and 3 women. 5/9 (55.5%) had skeletal lesions in which 3/5 (60%) had extensive skeletal involvement, 1/5 (20%) had lesion in C5/C6 vertebrae, 1/5 (20%) had right iliac bone involvement. While 1/9 (11.1%) had lesion in suprasellar region, 1/9 (11.1%) had lesion in the left scalp with extra and intracranial components involving greater wing of sphenoid. 1/9 (11.1%) had right orbit involvement, 1/9 (11.1%) patients had vulva involvement.

Conclusion

Most LCH lesions were FDG-avid, F-18 FDG PET/CT helps in identifying active bone lesions and also useful in clinically and radiographically silent bone LCH. Comprehensive and systemic assessment by PET/CT via metabolic activity of lesions provides more accurate diagnosis and therapeutic monitoring making it option for both diagnosis and evaluating curative effect of LCH.

ABAOCNMB054: Synchronous Gastric GIST and Metastatic Pancreatic Adenocarcinoma Unveiled by 18F FDG PET/CT: A Rare Collision

Tanvi Sarwal, Aditi Khurana, Tejesh P. Singh, Deepa Kumar, Padma Namgyal, Ravinder Sethi

Department of Nuclear Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India

Introduction

Synchronous primary malignancies are rare and pose diagnostic challenges, as distinguishing metastasis from a separate tumor is crucial for management. Gastrointestinal stromal tumors (GISTs) are uncommon mesenchymal neoplasms, while pancreatic adenocarcinoma is an aggressive epithelial tumor with poor prognosis. The coexistence of these two malignancies is extremely rare, with only a single case reported in literature. We present a patient with synchronous gastric GIST and pancreatic adenocarcinoma detected on 18F fluorodeoxyglucose positron emission tomography/computed tomography (18F FDG PET/CT).

Methods

A 58-year-old gentleman presented with severe, persistent abdominal pain radiating to the back and progressive weight loss for 4 months. Initial ultrasound was inconclusive. CECT revealed a distal pancreatic mass, multiple hypodense liver lesions, and a gastric nodule.

Results

18F FDG PET/CT was performed for staging and metabolic characterization. FDG PET/CT showed an FDG avid mass involving distal body and tail of pancreas, with multiple FDG avid abdomino-retroperitoneal lymph nodes, multiple liver lesions, peritoneal deposits and pulmonary metastases. Interestingly, the gastric lesion showed no FDG uptake, raising suspicion of a separate pathology rather than metastasis.

CA 19-9 was markedly elevated (> 20,000 u/mL). Endoscopic ultrasound-guided biopsies were performed from the pancreatic mass, periportal lymph nodes, and gastric lesion. Histopathology of the pancreatic specimen confirmed adenocarcinoma pancreas, while periportal lymph nodes showed metastatic involvement. The gastric lesion demonstrated whorls of spindle cells arranged in fascicles, low mitotic index (1–2/HPF) and were positive for CD117 and DOG, consistent with GIST.

he patient was not a surgical candidate due to extensive metastases. He was started on FOLFIRINOX for pancreatic cancer and imatinib for GIST. After four cycles, significant symptomatic improvement with weight gain was noted.

Conclusion

This case highlights the importance of comprehensive metabolic imaging and histopathological confirmation when evaluating multiple lesions. 18F FDG PET/CT was crucial in differentiating metastatic disease from a synchronous tumor. Although rare, the coexistence of gastric GIST and pancreatic adenocarcinoma should be considered, particularly in patients with familial cancer history. Thorough evaluation enables accurate diagnosis, guides optimal management, and improves patient outcomes.

ABAOCNMB108: A Rare Musculoskeletal manifestation of Non-Hodgkin’s Lymphoma: Isolated Scapular and Biceps Tendon involvement.

Sathya Narayanan, Harinee Ganesan, Sainath Ragire, Harish Goyal

JIPMER

Introduction

Non-Hodgkin’s lymphoma (NHL) predominantly arises from lymph nodes, accounting for nearly 80–90% of all lymphomas. Extranodal involvement occurs in approximately 25–40% of cases, with the gastrointestinal tract, skin, Waldeyer’s ring, lung, and central nervous system being the most common sites.^1-3 Musculoskeletal involvement is uncommon, and primary involvement of tendons is exceedingly rare. We present a case of a 46-year-old woman with primary extranodal NHL involving the scapula and biceps tendon, a rare musculoskeletal manifestation without nodal disease, highlighting the diagnostic and therapeutic role of F-18 FDG PET/CT.

Materials and Methods

A 46-year-old woman presented with a six-month history of pain and swelling in the right shoulder. NCCT imaging revealed a mixed lytic–sclerotic lesion in the right scapula. Biopsy of the lesion confirmed high-grade B-cell NHL, with immunohistochemistry positive for CD45, CD20, BCL6, BCL2, C-MYC, and MUM1. Baseline F-18 FDG PET/CT demonstrated metabolically active lesions in the right scapular region and an ill-defined FDG-avid lesion involving the long head of the right biceps tendon. No other sites of disease were detected, confirming isolated musculoskeletal involvement.

Results

The patient underwent six cycles of R-CHOP chemotherapy. Interim and follow-up PET/CT scans were used for treatment response assessment. Post-treatment imaging demonstrated mild diffuse FDG uptake in the right glenoid region, interpreted as reactive change, with complete metabolic resolution of scapular and tendinous lesions. This was consistent with a complete metabolic response. The patient showed significant clinical improvement in shoulder pain and swelling. The case underlines the rarity of primary musculoskeletal extranodal NHL, especially with tendinous involvement, and the diagnostic challenge posed by its nonspecific clinical and radiological features, which may mimic myositis, sarcoma, or metastatic disease. Definitive diagnosis required histopathology, while FDG PET/CT proved critical for staging and response evaluation.

Conclusions

Primary musculoskeletal NHL without nodal disease is exceptionally rare, with tendinous involvement being even more uncommon.^4,5 This case emphasizes the diagnostic importance of integrating imaging and histopathology, and underscores the role of FDG PET/CT in diagnosis, staging, and treatment monitoring. Although advanced-stage skeletal muscle NHL generally carries a poor prognosis, this patient demonstrated a favorable response to R-CHOP chemotherapy, highlighting the potential for good outcomes with timely diagnosis and therapy.

ABAOCNMB266: 18F-FDG PET/CT in Gastric Carcinoma: Imaging Patterns, Metastatic Profiles, and Diagnostic Challenges

A. Anirudh, H. Goyal, S. Kumar, S. Sundaramurthi, D. Halanaik;

Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER), Pondicherry, INDIA.

Introduction

Gastric carcinoma is one of the leading causes of cancer-related mortality worldwide. 18F-FDG PET/CT imaging is essential for staging the disease, evaluating treatment response, and determining prognosis. This type of cancer exhibits a variety of metabolic and metastatic characteristics, along with tumor biology, presenting challenges for conventional 18F-FDG PET/CT imaging. This study aimed to evaluate the imaging patterns and metastatic profiles of patients with gastric carcinoma, providing insights into its biological behaviour and the diagnostic challenges encountered.

Materials and Methods

A retrospective analysis was performed on histopathologically confirmed cases of gastric carcinoma evaluated using 18F-FDG PET/CT at a tertiary care hospital in South India. The imaging findings were categorized based on the uptake patterns observed in the primary tumor, lymph node involvement, and distant metastases, focusing on typical imaging presentations and various histological types.

Results

This retrospective study included 30 participants (19 males, 11 females; mean age of 56.6 years). The most common histological subtype was adenocarcinoma (including poorly cohesive, signet ring cell variants and mucinous carcinoma) (96.66%) followed by neuroendocrine carcinoma (3.33%). Significant variability in FDG uptake patterns was noted amongst the primary tumors, including focal, segmental, and diffuse distributions (overall mean SUVmax: 9.094 ± 4.048). Nodal metastases predominantly involved loco-regional lymph nodes (83.33%). Distant metastases were observed in 86.66% of the study population with peritoneal disease being the commonest site (30%), closely followed by skeletal metastases (26%). Virchow’s nodes (10%), Krukenberg tumors (6.66%) and Sister Mary Joseph nodules (3.33%) were also evident. Distinct imaging patterns were observed in specific subtypes: linitis plastica, for instance, demonstrated intense FDG uptake with circumferential gastric wall thickening. However, certain histologies such as signet-ring variant (SRV), and neuroendocrine tumors (NETs) exhibited low or absent FDG avidity. Additional imaging with 68Ga-FAPI PET (for SRV) and SSTR PET/CT (for NETs) aided diagnosis in these cases. Additionally, the cohort included cases of synchronous malignancies (e.g., lung cancers) and metachronous secondary malignancies (such as cervical carcinoma), highlighting the importance of PET/CT in comprehensive gastric cancer evaluation.

Conclusion

The 18F-FDG PET/CT scan is a valuable tool for evaluating gastric carcinoma’s imaging patterns and metastatic profiles. It has shown high sensitivity for most subtypes; however, it has limitations in detecting low FDG-avid tumors, such as signet-ring cell carcinoma (SrCC) and neuroendocrine tumors (NETs). These findings enhance our understanding of the metastatic behaviour and patterns of gastric carcinoma, as well as the role of PET/CT in treatment planning.

ABAOCNMB102: Correlation Analysis study Unravelling the Imaging Phenotype of multiorgan Mucinous Carcinomas with 18 F FDG PET CT scan based metabolic Parameters, CT Features, and Metastatic Trends

Madangopal Vishnoi, Braj Kishore Singh, Satish Vempa, Anurag Jain, Dharmesh Paliwal, Kartikey Solanki

Army Hospital Research and Referral Delhi Cantt

Introduction

Mucinous carcinomas constitute a distinct histological subtype of adenocarcinoma characterized by abundant extracellular mucin production, accounting for more than 50% of tumour volume. These neoplasms can originate from various anatomical sites including gastrointestinal tract, ovaries, lung, pancreas, and other organs, each demonstrating unique biological behaviour and clinical outcomes¹.

The heterogeneous nature of mucinous carcinomas across different organ systems presents significant diagnostic and therapeutic challenges. While conventional imaging provides morphological information, functional imaging with 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) offers insights into tumour metabolic activity through standardized uptake value (SUV) measurements².

Methods

We retrospectively analysed 46 patients diagnosed with mucinous carcinoma. Patient demographics, primary tumour characteristics, SUV max values from PET scans, CT findings, metastatic status, and treatment responses were evaluated. Statistical analysis included descriptive statistics, Pearson correlations for continuous variables, independent t-tests for group comparisons, and chi-square tests for categorical associations. Statistical significance was set at p<0.05.

Results

The cohort included 46 patients (male: 17, 37.0%; female: 29, 63.0%) with a mean age of 46.5 ± 14.8 years (range: 16-74 years). Rectum (n=12, 26.1%) and colon (n=10, 21.7%) were the most common primary sites. Mean tumour size was 5.4 ± 5.8 cm (range: 1.0-23.6 cm). Mean SUV max was 4.7 ± 4.3 (range: 1.0-19.82). Thirty patients (65.2%) presented with metastatic disease, with lymph nodes being the most common metastatic site (83.3% of metastatic cases). Soft tissue density on CT was observed in 40 patients (87.0%). No significant correlation was found between tumour size and SUV max (r = -0.047, p > 0.05).

Conclusions

Mucinous carcinoma predominantly affects the gastrointestinal tract with a female predominance. The majority of patients present with metastatic disease, primarily involving lymph nodes. The relatively low SUV max values may reflect the characteristic low metabolic activity of mucinous tumours.

These findings emphasize the importance of recognizing the unique clinical and imaging characteristics of mucinous carcinomas for appropriate patient management. The relatively low SUV max values should not be misinterpreted as indicating low tumour aggressiveness, as evidenced by the high rate of metastatic disease at presentation.

ABAOCNMB128: 68Ga FAPI PET/CT in Primary Breast Cancer: Correlation with Tumor Phenotype, Proliferation and FDG Uptake.

Dr Pratyusha Bikkina, Dr Zakir Ali, Dr Ajit N, Dr Harsh Pal.

Basavatrakam Indo American Cancer Hospital and Research Institute

Introduction

68GaFibroblast Activation Protein Inhibitor (FAPI) PET/CT is an emerging modality that visualizes tumor stroma. Breast cancer subtypes differ in biology and stromal desmoplasia, yet the relationship between stromal FAPI uptake, receptor phenotype, and metabolic activity remains underexplored.

Material and Methods

70 treatment-naïve women with histologically confirmed primary breast cancer underwent both 68Ga-FAPI and 18F-FDG PET/CT. SUVmax of the primary lesion was recorded. Tumors were classified into luminal (n=39), HER2-enriched (n=16), and triple-negative breast cancer (TNBC; n=15) based on immunohistochemistry. Kruskal–Wallis with post-hoc Mann–Whitney U (FDR-BH correction) was applied for between-group comparisons. Spearman correlation tested association of FAPI SUVmax with Ki-67 index and FDG SUVmax.

Results

Median 68GaFAPI SUVmax was 16.1 (IQR 12.1–19.8) for luminal, 21.7 (16.5–30.5) for HER2-enriched, and 22.8 (15.3–25.6) for TNBC subtypes. Differences across groups were significant (H = 11.18, p = 0.0037). Post-hoc analysis revealed higher uptake in HER2-enriched vs luminal (p_adj = 0.016) and TNBC vs luminal (p_adj = 0.017), with no significant difference between HER2-enriched and TNBC. FAPI SUVmax showed a weak but significant correlation with Ki-67 (ρ = 0.25, p = 0.038) and a moderate correlation with FDG SUVmax (ρ = 0.40, p = 5.6×10⁻⁴).

Conclusion

68Ga-FAPI uptake is significantly higher in aggressive phenotypes (HER2-enriched, TNBC) compared with luminal breast cancers. FAPI SUVmax correlates with proliferative activity and metabolic uptake, highlighting its potential role as a complementary biomarker of tumor aggressiveness and stromal biology in breast cancer.

ABAOCNMB117: Freeze-dried kit of ⁶⁸Ga/¹⁷⁷Lu-FAPI-2286 for Tumor Imaging/Therapy

Manoj Kumar^a, Akanksha Jain^a, DrishtySatpati^*a,b, Tapas Das^a,b

^aRadiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India; ^bHomi Bhabha National Institute, Mumbai, India

Introduction

FAPI-2286 is a cyclic peptide exhibiting high selectivity towards fibroblast activation protein (FAP) expressed in several types of tumors. ⁶⁸Ga- and ¹⁷⁷Lu-labeled FAPI-2286 have been developed as clinically promising radiotracers fordetection and therapy of wide range of cancers. In this study, the peptide FAPI-2286 was indigenously synthesized and freeze-dried kits were developed for one-step formulation of ⁶⁸Ga-FAPI-2286 and ¹⁷⁷Lu-FAPI-2286.

Materials and Methods

The linear peptide Hex-Cys-Pro-Pro-Thr-Gln-Phe-Cys-OH was synthesized manually on solid phase followed by cyclization and conjugation of the bifunctional chelator, DOTA in solution phase. Purified FAPI-2286 peptide was characterized by mass spectrometry. Radiolabeling parameters were optimized by performing wet radiolabeling. Freeze-dried kit for ⁶⁸Ga-labeling was prepared by mixing aqueous solutions of peptide (50 µg), sodium acetate and ascorbic acid (5 mg) followed by lyophilization.⁶⁸Ga-FAPI-2286 was formulated by addition of ⁶⁸GaCl₃(185 MBq, 2 mL, 0.1 N HCl) eluted from ⁶⁸Ge/⁶⁸Ga generator (JSC, Russia) to the kit and incubation at 90°C for 10 min. Contents of freeze-dried kit for ¹⁷⁷Lu-FAPI-2286 were peptide (270 µg), sodium acetate and ascorbic acid (10 mg) in lyophilized form. Kit was formulated by addition of ¹⁷⁷LuCl₃ (7400MBq) and incubation at 90^o C for 30 min.

Results

The peptide, FAPI-2286 was obtained in >99% purity and >30% yield. Radiolabeling yield of kit formulated ⁶⁸Ga-FAPI-2286 was >95% and of ¹⁷⁷Lu-FAPI-2286was>98% as determined from RP-HPLC.

Conclusion

Freeze-dried kits could be successfully prepared using indigenously synthesized FAPI-2286 peptide. Radiotracers could be formulated in high yield. In summary freeze-dried kits developed can be utilized for simple and quick formulation of ⁶⁸Ga/¹⁷⁷Lu-FAPI-2286 at clinics.

ABAOCNMB050: Prone Versus Supine position by 18F-FDG PET CT in Detection of Breast Cancer-a hanging breast technique. Prone vs Supine PET in Breast Cancer

Jain Anurag, Bushra Asima, Balan Vikrant

CHCC Lucknow

Background

Conventional [18F]fluorodeoxyglucose (18F-FDG) PET imaging of the breast is typically performed in the supine position, which may flatten breast tissue and obscure lesions due to overlap with adjacent structures.

Aim

To compare the diagnostic efficacy of prone versus supine 18F-FDG PET/CT imaging in breast cancer detection-with a hanging breast technique.

Materials and Methods

Total three cases done Patients received 0.16 mCi/kg of body weight of 18F-FDG intravenously. Whole-body PET/CT scans were performed 40 minutes post-injection using a GE Discovery 690 PET/CT system.

For prone imaging-hanging breast technique:

• Patients were positioned face down.

• A polyfoam pad with a central opening supported the chest, allowing breasts to hang freely.

• Regional imaging of the breast and thorax was performed to enhance lesion localization.

Results

Prone imaging with hanging breasts, improved lesion visualization and localization in all three cases, especially in dense fibroglandular tissue. It facilitated better separation of breast tissue from the chest wall, enhancing diagnostic accuracy.

Conclusion

Prone hanging breast technique by 18F-FDG PET/CT imaging offers superior lesion detection and localization compared to conventional supine imaging.

ABAOCNMB049: Detection of Occult Recurrence Using FAPI PET-CT in a Treated Case of Periampullary Adenocarcinoma with Biochemical Progression and Negative FDG PET-CT

Dr Rohit Kakde, Dr Amol Dongre

American Oncology Institute and Nangia Speciality Hospital

Introduction and Aims

Fluorodeoxyglucose (FDG) PET-CT is routinely used in oncologic imaging; however, its sensitivity is reduced in mucinous, low-glycolytic, or fibrotic tumors. Fibroblast Activation Protein Inhibitor (FAPI) PET-CT, by targeting cancer-associated fibroblasts, provides a novel alternative. This case aims to demonstrate the utility of FAPI PET-CT in a treated case of periampullary adenocarcinoma with rising CA 19-9 levels and inconclusive FDG PET-CT.

Materials and Methods

A 60-year-old male previously treated with Whipple’s surgery and chemotherapy for periampullary adenocarcinoma, and microwave ablation for solitary liver metastasis, presented on follow-up with rising serum CA 19-9 levels. FDG PET-CT showed no active disease. Due to clinical suspicion, FAPI PET-CT was performed.

Results

FAPI PET-CT demonstrated focal uptake in the ablated liver segment VII and revealed a new sub-centimeter lesion in segment V, both not visualized on FDG PET-CT. These findings correlated with the biochemical rise in CA 19-9, suggesting early recurrence.

Conclusion and References

This case highlights the diagnostic advantage of FAPI PET-CT over FDG PET-CT in detecting fibrotic or low-glycolytic recurrent disease. FAPI imaging may be considered in cases with biochemical progression and negative conventional PET-CT findings. Further studies are warranted to define its role in routine oncologic surveillance.

ABAOCNMB061: COMPARATIVE EVALUATION OF THREE CARDIAC SOFTWARE PACKAGES (ECTB, Cardiogam and Myovation Evolution) FOR ANALYSIS OF MYOCARDIAL PERFUSION IMAGING AND DERIVING THE QUANTITATIVE PARAMETERS: COMPARISON WITH 2D-ECHOCARDIOGRAPHY

Amal Paul, Ashwini Kalshetty, Sandip Basu

RADIATION MEDICINE CENTRE, MUMBAI

Introduction, Aims

Myocardial perfusion scintigraphy (MPS) and two-dimensional echocardiography (2D ECHO) are modalities used for evaluating left ventricular (LV) function and ejection fraction (EF). Software programs like Emory Cardiac Toolbox (ECTb) and Myovation Evolution (ME) offer semiquantitative and functional parameters for interpretation. Cardiogam (Cgam) is relatively a newer software which has undergone limited research. The goal of this study was to validate the semiquantitative and functional parameters derived from Cgam with ECTb and ME. Furthermore, the software derived EF were analysed in comparison with 2D ECHO.

Materials and Methods

This observational study involved 370 patients who underwent myocardial perfusion scintigraphy. Participants were stratified into three groups based on left ventricular ejection fraction (LVEF) determined by two-dimensional echocardiography (2D ECHO)- Group I- Low-risk individuals with preserved LVEF (EF >50%) and no prior cardiac history, Group II- Patients with a history of ischemic heart disease and preserved LVEF (EF >50%), Group III- Patients with reduced LVEF (EF <50%) as assessed by 2D ECHO. Semiquantitative parameters (summed rest score [SRS], summed stress score [SSS], summed difference score [SDS]) and quantitative parameters (defect extent [DE], transient ischemic dilatation [TID], ejection fraction [EF], end-diastolic volume [EDV], end-systolic volume [ESV], and stroke volume [SV]) derived from each software platform were analysed. Spearman’s rank correlation coefficient was employed to assess the relationships between these parameters within the entire cohort and across the three subgroups.

Results

The analysis demonstrated a strong correlation among majority of the parameters across the three software programs (ECTb, Cgam, ME). Group-wise comparison revealed that Group III (high-risk features with low EF, < 50%) exhibited the highest consistency in parameter agreement across software. LVEF values also showed good concordance with 2D ECHO, particularly in Group III. Among the 3 softwares, ME showed the closest alignment with 2D ECHO for EF assessment (Spearman rho, r=0.7).

Conclusion

Although ECTb, Cgam, and ME show strong inter-software and 2D-ECHO correlations for several parameters, notable differences exist in their diagnostic accuracy and levels of automation. To address these differences, it is advisable to use the same software for myocardial perfusion quantification when assessing patients over time or comparing results between them.

ABAOCNMB158: Designing Iodinated Phosphorylated Galactosylated Chitosan for Improved Liver Cancer Theranostics

Shuchika D Biligere¹, Vasumathi Ramesh¹, Yawar Bashir¹, Maya P. Shetty¹, Sanjay Bharati¹

*¹Department of Nuclear Medicine, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India.

Introduction and Aims

Hepatocellular carcinoma (HCC) remains a major clinical challenge with high rates of recurrence and limited targeted treatment options. Modified polysaccharides such as phosphorylated galactosylated chitosan offer enhanced hepatic targeting and antioxidant capabilities. This research set out to construct and thoroughly investigate an iodinated form of phosphorylated galactosylated chitosan aimed at advancing theranostic strategies for HCC.

Materials and Methods

An in-vitro experimental approach was employed involving three sequential chemical modifications of chitosan. Initially, phosphorylation was carried out with orthophosphoric acid in N,N-dimethylformamide, yielding a water-soluble polymer rich in phosphate functionalities. The synthesised phosphorylated chitosan underwent galactosylation using lactobionic acid conjugation via carbodiimide chemistry, optimising liver-selective uptake through asialoglycoprotein receptor affinity. The final iodination step utilised sodium iodide and chloramine-T to incorporate iodine into the polymer structure. The completed product was isolated and underwent extensive dialysis. Key analytical techniques included Fourier-transform infrared spectroscopy (FTIR) for functional group analysis, proton nuclear magnetic resonance (NMR) for molecular confirmation, scanning electron microscopy and energy dispersive X-ray (SEM-EDX) for morphology and elemental assessment, as well as liquid chromatography–mass spectrometry (LC-MS) to elucidate chemical composition and fragmentation.

Results

Iodinated phosphorylated galactosylated chitosan was readily water-soluble and crystalline in appearance. FTIR displayed notable alterations in absorption bands, confirming successful sequential phosphorylation, galactosylation, and iodination. The presence of characteristic iodine-related peaks, as well as confirmation of hypoiodous acid formation, supported structural modification claims. NMR spectroscopy identified corresponding proton shifts due to iodine addition. SEM-EDX confirmed the presence of carbon, nitrogen, oxygen, phosphorus, and iodine, while LC-MS data revealed fragments signifying the presence of iodinated, phosphorylated, and galactosylated subunits.

Conclusion

The sequential synthesis and multi-modal characterisation of an iodinated, phosphorylated, and galactosylated chitosan biopolymer were successful. These findings demonstrate the compound’s suitability as a precursor for radioisotope-labelled, liver-targeted agents in both HCC imaging and therapy, paving the way for further preclinical evaluation in theranostics.

ABAOCNMB255: Role of F-18 FDG PET-CT in Chordoma Patients: A Single Center Experience

Shamim A Shamim, Ritwik Wakankar, Sameer Rastogi, Yamini Dharmashaktu

All India Institute of Medical Sciences, New Delhi

Introduction/Aims

Chordoma is a slow-growing, locally invasive and aggressive form of tumor belonging to the sarcoma family of tumors and affects the midline spinal axis between the clivus and sacrum. This study aimed to examine the imaging features of F-18 FDG PET-CT of chordomas.

Material and Methods

We retrospectively collected the data of 23 patients with biopsy-proven chordoma ranging from January, 2013 to December, 2024.

Results

A total of 23 patients were included (18 males and 5 females; mean age of 46.4±16.9 years). This included 7 sacral, 8 sacrococcygeal, 6 cervico-dorso-lumbar spine, 1 petroclival and 1 skull base lesions. The histopathology of the lesions was as follows: 21 conventional & 2 poorly differentiated chordomas. INI-1 expression loss data was available for 22/23 patients, out of which 2 lesions showed loss of INI-1 expression. 3 patients presented with local tumor recurrence & 1 patient presented with both local and metastatic tumor recurrence. Metastatic disease was present in 7/23 patients. Only 10 patients had resectable disease at time of PET-CT. On F-18 FDG PET-CT, chordomas demonstrated a mean standardized uptake value (SUVmax) of 5.6±2.2, mean metabolic tumor volume (MTV) of 163.2±238.2 cc and mean total lesion glycolysis (TLG) of 259.1±191.8g. There was a significant difference in SUVmax between metastatic and non-metastatic chordomas (6.9 vs 4.9, P=0.014). No significant difference was found in SUVmax, MTV & TLG between chordomas based on tumor differentiation or INI-1 expression, however, it was noted that chordomas with poor differentiation and loss of INI-1 expression did have higher SUVmax & TLG.

Conclusion

On F-18 FDG PET-CT imaging, chordomas demonstrate variable, largely heterogeneous FDG uptake. This inherent FDG avidity suggests that it may be a useful modality in the staging, response evaluation and assessment of recurrent or metastatic disease and even in the histopathological & IHC characterisation of chordomas.

ABAOCNMB044: “Variation in heart rate response to adenosine stress in coronary artery disease patients showing single or double vessel involvement in myocardial perfusion imaging”

Khagesh Yadav, Vandana K Dhingra

AIIMS Rishikesh

Introduction

Adenosine induces vasodilation and a heart rate increase that reflects autonomic activity and may offer additional clinical value. However, the influence of coronary artery disease (CAD) burden—particularly in single versus double vessel disease—on heart rate response to adenosine stress remains unclear. Understanding this relationship may help in refining the interpretation of myocardial perfusion imaging (MPI) findings in these patient subsets.

Aim

Primary: To evaluate the variations in heart rate to adenosine stress in patients showing single or double vessel involvement in MPI.

Secondary: To evaluate the variations in HR to adenosine stress based on age and sex.

Materials and Methods

This retrospective study included patients (from 2019 to 2024) with known CAD who underwent adenosine stress MPI. HR was recorded at baseline and during peak stress. Patients were classified based on ischemia territory (single or double vessel involvement), sex and age. Statistical analysis was performed using SPSS software with a significance threshold of p < 0.05.

Results

A total of 44 patients were analyzed overall and sub group analysis was done based on age, gender, and ischemia territory (single or double vessel involvement) based on stress MPI outcomes. Age-based comparisons included patients aged below and above 55 years, as well as a subgroup analysis of males and females under 55 years. The findings are presented in tabulated form.

Conclusion

Adenosine infusion significantly increased heart rate, but this response did not vary with the extent of ischemia in single- or double-vessel disease (i.e. disease burden). In our cohort, age- and sex-related variations were minimal, differing from literature that reports greater increases in younger females due to autonomic and hormonal factors. This difference may reflect matched baseline characteristics through propensity score matching, medication effects, and the relatively small number of female participants.

ABAOCNMB041: Prognostic value of Radionuclide Imaging with specific Reference to Limb tumors

G.K. Rangarajan, Vivekanandan N, Krishnakumar R, Anand Raja, Chandrakumar

Cancer Institute (WIA) Adyar

Introduction

Osteosarcoma (OS) is defined as the primary malignant mesenchymal bone tumor where the malignant tumor cells originate directly from the osteoid or bone or both (1). Osteosarcomas and Ewing’s sarcomas are third most common cancer in young adult group, lymphomas and brain tumors being more prevalent. ES has an incidence 0.3 per 100,000 per year. It occurs most frequently and predominantly in pediatric, adolescent and also in adult groups.

Aim

The study aims to give appropriate measurements for making prosthesis with the use of Bone scan, MRI scan and Digital radiographs to lead better quality of remaining part of their life.

Materials and Methods

Patients with malignant bone tumor of Osteosarcoma and Ewing’s sarcoma of lower/upper limbs enrolled from July 2019 to August 2023 at the Institute were taken up for the prospective study. From 122 patients we have divided into two groups, Pre chemo studies and Pre and post chemo studies and each group consists of 122 and 83 patients. Totally, around 205 patients were eligible for this study and Tc99m MDP bone scan, MRI scan and Digital Radiography were taken for all these patients.

Statistical Analysis: Measures of central tendency and deviation were employed to describe the data as tables (Mean, SD, median, range, %difference, etc.) and graphs (boxplots, etc.) Paired t – test for differences in mean values. Karl-Pearson correlation co-efficient to establish direct relationship between MRI, Bone scan and HPE values in pre and post chemo settings were done.

Results

In Pre chemo study, was carried out involving 122 patients, which included 77 males and 45 females and p value < 0.001 and 90% cut off percent change value is 18.3% for pre chemo bone scan and HPE values. Pre chemo & Post chemo study, was carried out involving 84 patients, which included 51 males and 33 females and p value < 0.087 and 90% cut off percent change value is almost equal for pre chemo MRI scan and HPE values

Conclusion

Pre chemo study, it can be concluded that pre chemo bone scan, MRI scan and Digital radiography measurements are comparable and statistically analyzed using paired t test. Post chemo Bone scan tumor length variation only 8.2% and MRI scan measurements are almost equal when compare to post-operative tumor measurements.

ABAOCNMB121: Mito-TEMPO:n mitochondria-targeted antioxidants Shield Against UV-Induced Skin Carcinogenesis in Swiss Albino Mice

Anjali Singh¹, Sachin Shetty^1,2, Ghan Bahadur Damai¹, Anushree. U^1,3, Prasad Kisan Tambe¹, Sanjay Bharati^1*

¹Department of Nuclear Medicine, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal (576104), India, ²Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal (576104), India, ³Medical Instrument Devices and Allied services (MIDAS) DST-MAHE HUB, Manipal Academy of Higher Education, Manipal (576104), India

Introduction and Aim

Evidence suggests that ionizing radiation like UVB induces excessive production of free radicals within mitochondria leading to severe consequences like skin carcinogenesis. Conventional antioxidants were helpful to treat this only up to a certain extent due to lack of specificity at actual site of ROS generation i.e. mitochondria. Present study reports the formation of UV induced skin cancer and its protection by mitochondria targeted antioxidant.

Methods

Swiss albino mice were exposed to UVB followed by BaP topically. The induction of skin cancer was confirmed through histopathology. Further, oxidative DNA damage, levels of pro-inflammatory markers, mitochondrial oxidative stress and activity of mitochondrial antioxidant enzymes were assessed in skin tissue to confirm protective effect of mito-TEMPO against UVB-induced skin carcinogenesis.

Results

An appreciable decrease in visible total number of skin tumours and improved histoarchitecture of skin tissue in terms of reduction in ulcer, inflammatory cells infiltration, absence of epithelial islands in dermis, presence of dysplastic features like pleomorphic nuclei, individual cell keratinization, and epithelial dysplasia were observed in Mito-TEMPO protected animals.

Conclusion

Mito-TEMPO would be potential agent to prevent UVB-induce skin carcinogenesis. Mitochondria-targeted antioxidant; UVB-induced skin carcinogenesis; Mito-TEMPO; oxidative DNA damage; mitochondrial oxidative stress.

ABAOCNMB039: High Altitude Injury in Military Medicine and the Role of Nuclear Medicine

Anurag Jain

CHCC Lucknow

Abstract

High-altitude deployments expose military personnel to extreme environmental conditions, including sub-zero temperatures that can lead to frostbite—a localized cold injury resulting in tissue ischemia and necrosis. Accurate early assessment of frostbite severity is critical for effective management, yet conventional clinical evaluation often falls short. This paper explores the role of nuclear medicine, specifically the 99mTc methylene diphosphonate (MDP) triple-phase bone scan, in delineating ischemic zones in frostbite injuries. Through a series of military case studies, we demonstrate how nuclear imaging facilitates early prognosis, guides medical versus surgical intervention, and enhances operational readiness in high-altitude military medicine.

Introduction

Frostbite is a cold-induced injury characterized by the freezing of skin and subcutaneous tissues, most commonly affecting extremities such as fingers, toes, ears, and nose. In military settings, prolonged exposure to high-altitude cold environments increases the risk of frostbite, which can compromise combat readiness and long-term health.

The pathophysiology involves:

• Vasoconstriction: Initial protective response to conserve core temperature.

• Ice crystallization: Extracellular and intracellular freezing damages cell membranes.

• Vascular compromise: Hypoxia, thrombosis, and necrosis follow prolonged exposure.

Despite its prevalence, early clinical assessment of frostbite severity remains ambiguous. Traditional classification (first to fourth degree) lacks precision in predicting tissue viability. This gap necessitates advanced diagnostic tools—enter nuclear medicine.

Nuclear Medicine and Frostbite: The 99mTc MDP Bone Scan

Principles of Triple-Phase Bone Scan

The 99mTc MDP bone scan comprises three phases:

• Perfusion Phase: Assesses blood flow immediately post-injection.

• Blood Pool Phase: Evaluates soft tissue tracer distribution.

• Skeletal Phase: Captures bone uptake 2–3 hours post-injection.

This imaging modality helps delineate:

• Zone of Coagulation: Irreversible tissue death.

• Zone of Stasis: Potentially salvageable tissue.

• Zone of Hyperemia: Least damage, viable tissue.

Clinical Utility

• Early Prognosis: Detects ischemic zones within days of injury.

• Treatment Planning: Differentiates between medical and surgical candidates.

• Surgical Precision: Guides level of amputation when necessary.

• Monitoring Recovery: Tracks reperfusion and healing.

Case Series: Military Applications

Case 1: Conservative Management Success

A 42-year-old soldier developed third-degree frostbite in the right great toe. Bone scan revealed reperfusion, indicating tissue viability. He was managed medically and recovered without deficits.

Case 2: Autoamputation Without Surgery

A 30-year-old mountaineer from Mt. Everest base camp showed ischemia in distal phalanges. Bone scan guided conservative management. Autoamputation occurred naturally, avoiding surgical intervention.

Case 3: Guided Surgical Intervention

A 29-year-old soldier presented with fourth-degree frostbite. Bone scan identified ischemic zones requiring amputation of distal phalanges. The procedure was successful, with no residual deficits.

Implications for Military Medicine

Operational Readiness

Rapid diagnosis and tailored treatment preserve limb function and reduce downtime, enabling faster redeployment.

Strategic Evacuation

Bone scans inform triage decisions during air evacuation from high-altitude posts

Preventive Insights

Data from nuclear imaging can inform gear design, cold exposure protocols, and training programs.

Conclusion

The integration of nuclear medicine into military frostbite management represents a paradigm shift. The 99mTc MDP bone scan offers objective, early, and actionable insights into tissue viability, enabling precise and personalized care. In high-altitude military operations, where time and accuracy are paramount, this tool enhances both clinical outcomes and mission effectiveness.

ABAOCNMB232: Unmasking the Invisible Leak: Detecting Occult Gastrointestinal Protein Loss with Technetium-99m Human Serum Albumin Scintigraphy

Muppidi Abhishek Mano, Ram Kumar E, K. K. Kamaleshwaran, Radhakrishnan E. R, Kingsley F. R, Arun Pandiyan, Aadhavan P, Jeba Getzi, Kowsalya R, Manoaj M.

Department of Nuclear Medicine, Kovai Medical Centre and Hospital, Coimbatore, India

Introduction

Protein-Losing Enteropathy (PLE) is a rare clinical entity characterized by excessive trans-enteric loss of plasma proteins, resulting in hypoalbuminemia and manifestations such as edema and chronic diarrhea. Owing to its non-specific presentation, diagnosis can remain elusive despite extensive evaluation. Accurate localization of the site of protein leakage is crucial for guiding therapy. This case highlights the diagnostic accuracy of Technetium-99m (⁹⁹ᵐTc) Human Serum Albumin (HSA) scintigraphy in confirming and localizing occult gastrointestinal protein loss in a patient with unexplained hypoalbuminemia.

Case Presentation

A 42-year-old female presented with progressive pedal edema, facial puffiness, and chronic non-bloody diarrhea. Laboratory evaluation revealed severe hypoalbuminemia (2.1 g/dL) with preserved hepatic and renal function. Both upper and lower gastrointestinal endoscopies were unremarkable, prompting referral for nuclear imaging to assess suspected PLE.

Investigations

⁹⁹ᵐTc-HSA was prepared under strict radiopharmaceutical quality-control procedures to minimize free pertechnetate (⁹⁹ᵐTcO₄⁻) contamination. A diagnostic dose of 740 MBq (20 mCi) was administered intravenously. Serial planar abdominal and pelvic images were obtained at 30 minutes, 1 hour, 3 hours, and 4 hours post-injection. Early images demonstrated normal blood-pool distribution without abnormal bowel activity.

Findings

Delayed imaging at 4 hours revealed new focal tracer accumulation along the jejuno-ileal loops, indicating extravasation of labeled albumin into the intestinal lumen. This finding confirmed active enteric protein loss, correlating with the patient’s biochemical and clinical profile.

Discussion

⁹⁹ᵐTc-HSA scintigraphy is a sensitive, non-invasive, and reliable imaging modality for detecting gastrointestinal protein loss, particularly when conventional investigations are inconclusive. The inclusion of delayed imaging is essential to capture intermittent or slow leaks, while rigorous labeling minimizes false-positive uptake from free pertechnetate in the stomach or thyroid.

Conclusion

⁹⁹ᵐTc-HSA scintigraphy precisely localized the intestinal site of protein leakage, establishing the diagnosis of Protein-Losing Enteropathy in this patient. This case underscores the modality’s simplicity, sensitivity, and the clinical impact in unveiling otherwise occult sources of gastrointestinal protein loss and guiding targeted management.

ABAOCNMB231: Incidental finding of a Jejunoileal Duplication Cyst during Meckel Scintigraphy

Carmel Frank Robin R, K K Kamaleshwaran, Ram Kumar E, Radhakrishnan E R, Kingsley F R, Arun Pandiyan, Aadhavan P, Jeba Getzi, Kowsalya R, Manoaj M

Nuclear Medicine Department, Kovai Medical Center and Hospital, Coimbatore, India.

Introduction, Aims

Radionuclide imaging using Technetium-99m pertechnetate (^99mTcO₄^-)is a well-established diagnostic technique to evaluate abdominal pain or gastrointestinal bleeding in patients suspected to have a Meckel’s diverticulum. Enteric duplication cysts, which are rare anomalies of the gastrointestinal tract, may be located in any part of the gastrointestinal system from the oral cavity to the anus, with a rarity of 10% occurrence in the jejunum. This case report aims to report the unexpected finding of a jejunal duplication cyst in a pediatric patient referred for a suspected finding of Meckel’s diverticulum.

Materials and Methods

An 8-year-old male patient was referred for a Meckel scintigraphy to investigate a suspected Meckel’s diverticulum. Following the intravenous administration of Technetium-99m pertechnetate, sequential dynamic abdominal images were acquired for 20 minutes, along with a subsequent static image at the end of the dynamic sequence. Additional Single Photon Emission Computed Tomography and Computed Tomography hybrid imaging (SPECT/CT) was performed for precise three-dimensional anatomical localization of any abnormal findings.

Results

The scan revealed physiological tracer uptake in the gastric mucosa, with normal excretion visualized in the kidneys and urinary bladder. An abnormal focus of progressively increasing tracer activity was identified along the distribution of the jejunal and ileal bowel loops. The SPECT/CT images precisely localized this abnormal uptake to a structure anatomically consistent with a duplication cyst, separate from a typical Meckel’s diverticulum. The scan findings are suggestive for jejunoileal duplication cyst.

Conclusion

Intestinal duplication cysts and Meckel’s diverticulum can diagnostically mimic each other in planar scintigraphy. This case highlights that while planar scintigraphy is sensitive for detecting ectopic gastric mucosa, its anatomical specificity is limited. The integration of SPECT/CT provides superior anatomical correlation, significantly enhancing diagnostic accuracy. This hybrid imaging approach is crucial for the correct preoperative identification of rare anomalies, thereby guiding appropriate surgical planning and preventing diagnostic error.

ABAOCNMB247: F-18 SODIUM FLUORIDE BONE SCAN IN A RARE CASE OF MELORHEOSTOSIS IN A 28 YEAR OLD MALE PATIENT: NUCLEAR MEDICINE PERSPECTIVE.

Shashank B, Tekchand Kalawat, R Ramya Priya, Rishma Shaik

Department of Nuclear Medicine, Sri Venkateswara Institute of Medical Sciences,

Tirupati -517507, Andhra Pradesh.

Introduction

Melorheostosis is a rare sclerosing bone dysplasia characterized by irregular cortical hyperostosis, often affecting the long bones. We present a case of melorheostosis in a 28-year-old male involving the right lower limb, detailing its clinical presentation, radiographic features, and the diagnostic role of F-18 sodium fluoride (NaF) bone scan.

Materials

A 28-year-old male presented with complaints of difficulty in walking and pain in right leg and ankle region and progressive stiffness. Initial radiographs revealed thickened, undulating cortical bone with a “dripping candle wax” appearance, consistent with melorheostosis. Further assessment included with MRI scan to evaluate adjacent soft tissue changes. F-18 NaF bone scan was performed to assess the extent of disease and metabolic activity.

Results

Radiographic imaging confirmed hyperostosis along the right tibia. MRI highlighted secondary soft tissue changes including muscle atrophy. The F-18 NaF bone scan demonstrated increased tracer uptake corresponding to areas of active bone remodelling, providing functional insights complementary to structural imaging modalities.

Conclusion

This case highlights the significant role of F-18 NaF bone scans in diagnosing melorheostosis, which provides crucial insights into the metabolic activity and disease extent of affected bones. Integrated multimodal imaging aids in early diagnosis, guides management strategies, and improves clinical outcomes by addressing functional impairment and pain management effectively. F-18 sodium fluoride whole body bone scan is a single step shot to give the panoramic view of all the involved bones.

ABAOCNMB071: GI Bleed case and review of RED BLOOD CELL LABELING

Khadeejathul Maziya, Dr Ali Sneivar, Fathima Nahala A S, Jeffin Sunny

Govt Medical College, Kozhikode

Introduction

In this poster, we are reviewing techniques of Red Blood Cell (RBC) labelling for nuclear medicine studies, along with a case study done in Department of Nuclear Medicine, Government Medical College Kozhikode. RBC labelling is an established nuclear medicine technique used to evaluate blood pool dynamics, especially in gastro intestinal (GI) bleeding.

Aim

For diagnosis and evaluation of site of GI bleeding.

Materials and Methods

Techniques of RBC labelling with Tc-99m can be done by

1. In vivo method

2. Modified in vivo(in vitro) method

3. In vitro (Brookhaven) method

4. In vitrocommercial kit (Ultratag).

Our case study involves the preparation of Tc-99m labelled RBC by modified in vivo method, application of labelling protocols and Imaging results via scintigraphy.

Results and Conclusion

In our patient with suspected GI bleeding, Tc-99m labelled RBC scintigraphy successfully localized active bleeding sites to jejunal loops in Superior Mesenteric Artery (SMA) territory. Subsequently selective angiogram of SMA was done. Bleeding point was localized and embolized. Post procedure patient improved and discharged. The labelled RBCs circulated for up to 24 hours, allowing for delayed imaging in intermittent bleeds. Early dynamic Imaging detects bleeding rates as low as 0.1mL/min. Delayed static images have improved detection accuracy in slow or intermittent bleeds.

ABAOCNMB239: Comparison of ¹⁸F-Fluorocholine PET/CT with ^99mTc-Sestamibi in detecting the parathyroid lesions in post-operative persistent/ recurrent hyperparathyroidism: A single centre study.

Priyank Rajput, Ashwani Sood, Rajender Kumar, Harmandeep Singh, Anish Bhattacharya, B.R Mittal.

PGIMER Chandigarh

Introduction

Primary hyperparathyroidism (PHPT) is a prevalent endocrine disorder, with definitive treatment typically involving the surgical removal of overactive parathyroid glands. Accurate localization of all hyperfunctioning glands is essential for performing targeted surgical procedures. Persistent and recurrent PHPT pose substantial challenges in the effective management of the PHPT. ¹⁸F-fluorocholine PET/CT has demonstrated promising accuracy in identifying hyperfunctioning parathyroid tissue and may replace ^99mTc-sestamibi scintigraphy for preoperative planning in parathyroid surgery. The aim of the study is to establish the efficacy of ¹⁸F-fluorocholine PET/CT over ^99mTc-sestamibi in persistent or recurrent PHPT for the localization of hyperfunctioning parathyroid tissue.

Materials and Methods

This retrospective study evaluated patients who developed persistent or recurrent primary hyperparathyroidism (PHPT) following parathyroid surgery. A total of 20 patients (mean PTH: 290 pg/ml) with clinically/ biochemically confirmed PHPT who had previously undergone parathyroidectomy were included. All 20 patients underwent both ⁹⁹ᵐTc-sestamibi and ¹⁸F-flurocholine PET/CT imaging. The diagnostic performance and localization findings of the two modalities were analyzed and compared.

Results

In 12 of 20 patients (60%), findings from ¹⁸F-fluorocholine PET/CT and ⁹⁹ᵐTc-sestamibi scans were concordant. In six patients (30%), no sestamibi avid lesions were identified; however, ¹⁸F-fluorocholine PET/CT revealed choline-avid lesions, suggestive of parathyroid adenomas. In one case, the ⁹⁹ᵐTc-sestamibi scan detected single left inferior parathyroid adenoma (LIPA), whereas ¹⁸F-fluorocholine PET/CT identified an additional lesion consistent with a left superior parathyroid adenoma (LSPA). In one patient, the ⁹⁹ᵐTc-sestamibi scan demonstrated a nodule posterior to the upper pole of the right thyroid lobe that lacked choline avidity.

Conclusion

The findings suggest that ¹⁸F-fluorocholine PET/CT is more effective in localizing hyperfunctioning parathyroid tissue in patients with persistent or recurrent PHPT, particularly in those with negative or inconclusive sestamibi scans. Furthermore, ¹⁸F-fluorocholine PET/CT demonstrated superior diagnostic performance, over ⁹⁹ᵐTc-sestamibi in localization of additional number of parathyroid lesions indicating that ¹⁸F-fluorocholine PET should be done upfront in these subset of patients.

ABAOCNMB277: Role of FDG PET-CT in Unmasking Lymphoproliferative Disorder Presenting as Refractory Frontal Osteomyelitis: A Case Report

Dharmesh Paliwal

Command Hospital (EC), Kolkata

Introduction and Aims

Osteomyelitis refractory to appropriate antimicrobial therapy and surgical debridement should prompt consideration of alternative diagnoses. Lymphoproliferative disorders can rarely present with osseous involvement mimicking infectious osteomyelitis, leading to diagnostic delays and inappropriate management. We present a case where FDG PET-CT was instrumental in revealing the true underlying diagnosis in a patient with presumed refractory osteomyelitis.

Materials and Methods

A 34-year-old male presented in December 2024 with right-sided facial pain, orbital pain, and intermittent fever. Initial NCCT head revealed right frontal osteomyelitis and ethmoiditis with subgaleal collection. Despite multiple antibiotic courses, CECT head in February 2025 showed progression with heterogeneously enhancing soft tissue overlying the frontal bone, permeative osteolysis crossing midline, and extradural extension. He underwent right frontal craniectomy with bone excision and debridement. Histopathology confirmed acute on chronic osteomyelitis. Despite continued antibiotics, he developed progressive right eye swelling in March 2025. Repeat CECT and MRI demonstrated extensive bilateral subgaleal collections, pachymeningeal thickening, bilateral orbital involvement with proptosis, and right pleural effusion. CECT chest revealed osteomyelitis of right 5th rib and left scapula with chest wall myositis. Given the atypical progression and multifocal involvement despite aggressive treatment, FDG PET-CT was performed in March 2025.

Results

FDG PET-CT revealed metabolically active subgaleal uptake in bilateral frontal regions extending into bilateral orbits, FDG-avid pachymeningeal thickening in bilateral frontal, parietal and temporal regions, FDG-avid pleural thickening in right hemithorax with right 5th intercostal space soft tissue involvement, multifocal FDG-avid skeletal lesions involving right frontal bone, right 5th rib, left 8th and 12th ribs and left scapula, three FDG-avid pancreatic foci, and FDG-avid right intraparotid and left axillary lymph nodes. The pattern of disseminated FDG-avid lesions with multifocal osseous, soft tissue, and nodal involvement raised strong suspicion for lymphoproliferative disorder rather than refractory infection. Review of histopathology confirmed lymphoproliferative disorder, and chemotherapy was initiated.

Conclusion

This case highlights the critical role of FDG PET-CT in identifying atypical presentations of lymphoproliferative disorders masquerading as refractory osteomyelitis. When infectious osteomyelitis fails to respond to appropriate therapy, whole-body metabolic imaging should be considered to evaluate for underlying malignancy. FDG PET-CT’s ability to demonstrate the extent and pattern of disease proved invaluable in establishing the correct diagnosis and directing appropriate management.

ABAOCNMB053: Prognostic Value of FDG PET/CT-Derived Volumetric Biomarkers in Pulmonary and Extrapulmonary Small Cell Carcinomas: An Ambispective Study

* Sulochana Sarswat¹, Abhinav Singhal¹, Aparna Sharma², Akash Kumar³, Babita Kataria⁴, Kalpa Jyoti Das¹

¹Department of Nuclear Medicine, National Cancer Institute, Jhajjar, All India Institute of Medical Sciences, New Delhi, India, ²Department of Medical Oncology, National Cancer Institute, Jhajjar, All India Institute of Medical Sciences, New Delhi, India

Background

Small cell lung cancer (SCLC) and extrapulmonary small cell carcinoma (EPSCC) are rare, aggressive neuroendocrine malignancies with limited prognostic tools beyond anatomical staging. This study evaluated the prognostic value of baseline FDG PET/CT–derived volumetric metrics in both subtypes.

Methods

This ambispective study included 60 patients (39 SCLC, 21 EPSCC) undergoing baseline FDG PET/CT. SUVmax, 40% threshold thoracic-extrathoracic (SCLC)/primary-extra-primary (EPSCC) and whole-body metabolic tumour volume (MTV)/total lesion glycolysis (TLG) were derived. Associations with progression-free survival (PFS) were assessed by Cox regression and ROC analysis after log-transformation of highly skewed parameters (>0.9).

Results

Among 39 SCLC patients (median age 58 years, 84.6% male; median PFS 184 days, range 48–510); 33 (84.6%) progressed, 3 (7.7%) died, 1 (2.6%) recurred post-complete metabolic response (CMR), and 2 (5.1%) sustained CMR. Median pSUVmax, pMTV, and pTLG were 9.9 (3.7–27.3), 446.0 cm³ (56.1–2970.0), and 1350.1 (70.3–7002.0); wbMTV and wbTLG were 1293.0 cm³ (310.4–11190.3) and 3772.0 (380.2–22429.0). On univariate Cox regression, all volumetric PET parameters and LDH predicted shorter (less than median) PFS; while on multivariate analysis, only log_tMTV (HR 2.09, 95% CI 1.10–4.00, p = 0.02) and log_LDH (HR 2.77, 95% CI 1.30–5.91, p = 0.01) were independent predictors. ROC analysis showed tMTV outperformed LDH (AUC 0.84, sensitivity 0.85, specificity 0.79 vs. AUC 0.74, sensitivity 0.40, specificity 1.00).

Among 21 EPSCC patients (median age 57.5 years, 80.9% male, median PFS 220 days, range 28–634); 14 (66.7%) progressed, 3 (14.3%) recurred after CMR, 2 (9.5%) died, and 2 (9.5%) sustained CMR. Median pSUVmax, pMTV and pTLG were 9.7 (4.5–29.6), 88.6 cm³ (32.9–570.8) and 244.5 (47.6–1626.0); wbMTV and wbTLG were 360.8 cm³ (32.9–5461.0) and 1037.9 (88.6–26005.0). On univariate analysis, several PET volumetric parameters, log_pSUVmean, LDH and VALSG-stage were significant; while multivariate analysis retained only log_wbMTV as independent predictor (HR 9.31, 95% CI 2.82–30.76, p < 0.001). ROC-analysis confirmed strong prognostic performance of wbMTV (AUC 0.91; sensitivity 81.8%, specificity 100%).

Conclusion

FDG PET/CT-derived volumetric biomarkers, particularly log_tMTV in SCLC and log_wbMTV in EPSCC, were robust independent predictors of disease progression. Serum LDH complemented PET metrics, showing independent value in SCLC but not EPSCC, though with weaker ROC performance. These parameters provide biologically relevant, site-agnostic prognostic insight, particularly valuable in EPSCC where anatomical staging lacks precision, and support integration of PET-based volumetrics into personalized risk-adapted management of small cell carcinomas.

ABAOCNMB063: 18 SODIUM FLUORIDE UPTAKE AT THE PRIMARY TUMOR SITE IN BREAST CANCER: CLINICAL AND DIAGNOSTIC INSIGHTS FROM PET-CT IMAGING

Nithya V, Tekchand Kalawat, N Rukmangadha, Silpa Kadiyala, Bhargavi D, R Ramya Priya.

Sri Venkateswara Institute of Medical Sciences (SVIMS)

Introduction

Fluorine-18 Sodium Fluoride (F-18 NaF) localises in areas of increased osteoblastic activity. Extraosseous uptake have been observed in various benign and malignant conditions, including primary breast tumors. One proposed mechanism includes, presence of intra-tumoral microcalcifications composed of hydroxyapatite crystals in malignant breast lesions. Preclinical studies have demonstrated that NaF can detect tumoral microcalcifications non-invasively at molecular level earlier than mammography. In light of these observations, the present study was designed to assess the significance of F-18 NaF localization in primary breast tumor.

Aim

To assess the association of bone seeking radiotracer uptake F-18 NaF in primary breast tumor site with radiological and histopathological parameters.

Material and Methods

In this prospective observational study, 106 treatment-naïve, histopathologically confirmed breast carcinoma cases undergoing F-18 NaF PET/CT (October 2023–December 2024) were evaluated. Tumoral NaF uptake was assessed visually and quantitatively. SUVmax of tumor (T) and contralateral normal breast tissue (N) was measured and the T/N ratio was calculated. Associations with BIRADS score, calcifications on mammography, tumor receptor status, metastases, and stage of cancer were analyzed using t-test and ANOVA. Spearman’s correlation evaluated relationships between T/N ratio, Ki-67 index, and tumor volume.

Results

Of the 106 patients included in the study, 105 (99.1%) were female and 1 (0.9%) was male, with a mean age of 54.36 ± 11.2 years. 60/106 patients (56.6%) were either overweight or obese (BMI > 23.0 kg/m²), and 68/105 females (64.8%) were postmenopausal. On visual assessment, F-18 NaF uptake in the primary breast tumor was observed in 65 patients (61.3%), while 41 patients (38.7%) showed no uptake. The mean T/N ratio was 1.92 ± 0.74. A higher T/N ratio was significantly associated with higher BIRADS scores (p = 0.014), HER2/neu positivity (p = 0.018), axillary lymph node metastases (p = 0.0047), and advanced TNM stage (p = 0.0015). HER2/neu-positive tumors showed significantly higher T/N ratios, while ER/PR-positive tumors had lower T/N ratio. Additionally, Ki-67 index and tumor volume showed a significant positive correlation with the T/N ratio (p = 0.0025 and p = 0.0015, respectively).

Conclusion

F-18 NaF uptake at the primary breast tumor site is often overlooked during routine bone scans. Our findings indicate a frequent association of NaF uptake with HER2/neu positivity, even in absence of mammographic microcalcifications. This suggests F-18 NaF uptake may serve as a non-invasive imaging biomarker to identify biologically aggressive tumors and guide targeted therapy in selected patients.

ABAOCNMB101: Can [¹¹C]PBR28 TSPO PET-MRI imaging helpful in making differential diagnosis of PD from PSP-RS.

Aishwarya Kumar, Pardeep Kumar, Venkatesh Murthy, Jitender Saini, Ravi Yadav¹, Madhavi Tripathi².

Department of Neuroimaging & Interventional Radiology, ¹Neurology, National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India, ²Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi.

Background

[¹¹C]PBR28 is a translocator protein (TSPO) receptor-targeting radiotracer, and many studies have used this tracer to quantify neuroinflammation in multiple neurodegenerative disorders. This study aims to explore its role in the differential diagnosis of Parkinson’s disease (PD) and progressive supranuclear palsy-Richardson syndrome (PSP-RS).

Methods

In this prospective study, seven PD and five PSP-RS patients (clinically diagnosed and assessed for UPDRS-III and PSPRS) were enrolled for [¹¹C]PBR28 simultaneous PET-MRI after rs6971 polymorphism genotyping. The qualified patients underwent a dynamic scan for 60 minutes. The protein biomarkers (GFAP, NfL, and IL-10) were quantified in the plasma samples. The midbrain volume was measured using the structural MRI imaging data. The SUV-R and DVR outcome parameters were calculated using the PET imaging data, and a comparative analysis was performed between the two diagnostic groups.

Results

The volume of the midbrain region was found to be 6.1 ± 0.6 cm³ and 7.9 ± 0.9 cm³ in PSP-RS and PD diagnostic groups, respectively. The Groupwise [¹¹C]PBR28 SUV-R showed significant differences in the midbrain (p < 0.05), pallidum (p < 0.05), substantia nigra (p < 0.01), and thalamus (p < 0.01). The Groupwise [¹¹C]PBR28 DVR showed a significant difference in the thalamus (p < 0.05) region. The %RSD for SUV-R was lower compared to DVR. The plasma NfL protein concentration was found to be higher in the PSP-RS group compared to PD (p < 0.05). The SUV_min of the thalamus area showed a negative Spearman’s correlation with plasma GFAP concentration in PD subjects.

Conclusion

The simple SUV-ratio-based quantification of [¹¹C]PBR28 can be a robust method for differentiating between PD and PSP-RS. Thus, TSPO neuroinflammation PET-MRI can provide new insights in differentiating between Parkinson’s and atypical Parkinsonism.

ABAOCNMB093: Metabolic Imaging and Molecular Profiling in Lung Carcinoma: Relationship between F-18 FDG PETCT Findings and Genomic/Immunologic Markers.

Ankur Pruthi¹, P S Choudhury¹, Manoj Gupta¹, Atul Pathak¹, Charulata Jindal²

¹Department of Nuclear Medicine, ²Department of Research, Rajiv Gandhi Cancer Institute & Research Centre, Rohini, New Delhi.

Introduction

Fluorodeoxyglucose positron emission tomography (FDG PET/CT) plays a pivotal role in the staging and prognostication of lung carcinoma. Molecular alterations such as EGFR, ALK, KRAS mutations and PD-L1 expression, are increasingly guiding treatment decisions. Establishing a correlation between FDG PET parameters and molecular markers may provide insights into tumor aggressiveness and help refine patient treatment. Previous studies on this subject have provided conflicting results. Moreover, there is a paucity of data analysing this correlation in Indian patients.

Materials and Methods

We conducted a retrospective study of 96 patients (Mean age 62.35 ± 11.35 years; 63 males, 33 females) with histologically proved lung carcinoma who underwent baseline FDG PET/CT and molecular profiling at our institution between April 2023 – July 2025. Demographic details, histology, stage, and smoking status were recorded. PET parameters analysed included the maximum standardized uptake value (SUVmax) of the primary lesion (pSUVmax), lymph nodes (nSUVmax) and metastatic site (mSUVmax). Molecular profiling were obtained for EGFR, ALK, KRAS, and other driver mutations. PD-L1 tumor proportion score (TPS) was determined by immunohistochemistry (IHC). Appropriate statistical tests were applied to assess correlations between clinical variables, PET parameters and molecular/PD-L1 status.

Results

A smoking history was present in 25% of patients. Adenocarcinoma was the predominant histology (71.8%) with the most common primary site in the right lung (n=58, 60.4%). At diagnosis, 67.7% patients had distant metastatic disease (M1). EGFR mutations were identified in 31 (33.3%), ALK rearrangements in 14 (15.9%), and KRAS mutations in 8 (10%) patients. PD-L1 positive expression (TPS >1%) was noted in 49.3% patients with high PD-L1 expression (TPS ≥ 50%) in 20% of tumors. EGFR mutations were found more frequently in females compared to males (48% vs. 25%; p=0.02) and in non-smokers. ALK-positive patients were more frequently seen in younger age group than ALK-negative patients (56 ± 10.7 vs. 63.21 ± 11.11 years; p = 0.02). EGFR wild-type status was significantly correlated with positive PD-L1 expression (p=0.05). SUVmax values were significantly higher in tumors with positive PD-L1 expression (TPS 1-49%) (p = 0.03). EGFR and ALK alterations showed lower pSUVmax and mSUVmax values, although these differences did not reach statistical significance.

Conclusion

Our study demonstrates that FDG PET parameters, particularly SUVmax, correlate with PD-L1 expression and may reflect tumor immunogenicity. Conversely, EGFR and ALK mutated tumors tend to display reduced glycolytic activity. These findings support the potential role of FDG PET/CT as a surrogate marker of tumor biology. Validation in larger, prospective cohorts is recommended.

ABAOCNMB138: Revolution vs Rivalry: Ga-68 Trivehexin PET/CT Face off Against Tc-99m Sestamibi, 4D CT, and Ultrasound in Parathyroid Imaging

Medha Dutta, J Mohan Roop, Kiran Pasam, Sridhar Dasu, Anuradha Sesikaran, Suneetha Batchu

AIG Hospitals

Introduction

Parathyroid adenomas are the leading cause of primary hyperparathyroidism. Precise preoperative localization is crucial for effective surgery. Conventional imaging like Tc-99m SESTAMIBI, 4D CT, and neck ultrasound (USG) show variable accuracy, especially for small or ectopic adenomas. Ga-68 Trivehexin, a novel PET tracer targeting αvβ6 integrin, combined with PET/CT’s superior functional and anatomical imaging, may improve sensitivity and specificity, aiding surgical planning and outcomes, particularly when other methods fail.

Aim

This study in 61 patients at AIG Hospitals, Hyderabad, prospectively determines:

• gender, size and location based adenoma incidences

• True Positives (TP), False Positives (FP), True Negatives (TN), False Negatives (FN), Sensitivity (Sn), Specificity (Sp), Positive and Negative Predictive Values (PPV, NPV), Diagnostic Accuracy (DA) and Likelihood Ratios (LR) of Ga-68 Trivehexin PET/CT against Tc-99m SESTAMIBI scan, 4D CT, and USG neck

• Size based comparison of Sn between Tc-99m SESTAMIBI and Ga-68 Trivehexin PET/CT

• Correlation analysis between Serum PTH and all four modalities

• McNemar’s test, Cohen’s Kappa and Incremental Cost-Effectiveness Ratio (ICER) between Ga-68 Trivehexin PET/CT and other three modalities

• Mean SUVmax of all physiological sites of tracer uptake

Methodology

Biochemically confirmed consenting primary hyperparathyroidism patients, underwent imaging with USG neck, Tc-99m SESTAMIBI SPECT/CT, Ga-68 Trivehexin PET/CT and/or 4D CT. Imaging results were validated against surgical and histopathological findings. Comparative diagnostic statistics and cost effectiveness metrics were calculated, highlighting intra-individual modality performance.

Results

Ga-68 Trivehexin PET/CT showed superior diagnostic accuracy compared to Tc-99m SESTAMIBI, USG neck, and 4D CT. Performance metrics were:

• Sensitivity: 97.2%% vs 44.4% vs 67.6% vs 85.1%

• Specificity: 96% vs 96% vs 66.6% vs 95.8%

• PPV: 97.2% vs 94.1% vs 71.8% vs 95.8%

• NPV: 96.5% vs 54.5% vs 62.1% vs 85.1%

• Diagnostic Accuracy: 96.7% vs 65.5% vs 67.2% vs 90.2%

• High LR+ and low LR- : Tvx > 4DCT > SESTAMIBI > USG

Sensitivity by adenoma size (Ga-68 PET/CT vs Tc-99m SESTAMIBI):

• <1 cm: 88.8% vs 40%

• 1.1-1.5 cm: 96% vs 69.2%

• 1.6-2 cm: 100% vs 88.7%

• >2 cm: 100% vs 100%

Conclusion

Ga-68 Trivehexin PET/CT therefore offers a significant advantage, especially when conventional imaging is inconclusive, supporting its role as a preferred preoperative imaging method for parathyroid adenoma localization.

ABAOCNMB165: Advancing from Perception to Precision: FDG PET/CT Radiomics Signatures Capture Histologic Grade and Sarcomatoid differentiation in patients with RCC

Palivela Dhanusree¹, Sameer Taywade¹, Rajesh Kumar¹.

¹Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, India.

Introduction

Renal cell carcinoma (RCC) encompasses heterogeneous tumors with diverse histological subtypes, grades, and differentiation patterns, all of which strongly influence prognosis and therapeutic strategy. Among these, sarcomatoid differentiation is a marker of aggressive biology and is associated with poor outcomes. Conventional FDG PET analysis are limited by variable FDG uptake and high background, reducing the reliability for accurate tumor characterization. Radiomics, by extracting quantitative texture features, provides a non-invasive method to capture intratumoral heterogeneity, offering potential advantages for pre-treatment risk stratification beyond conventional metabolic measures. This study aimed to evaluate the concordance of FDG PET-derived metabolic parameters and radiomic texture features with histological grade, subtype, and sarcomatoid differentiation in RCC.

Materials and Methods

This retrospective analysis included 27 RCC patients who underwent pre-treatment FDG PET/CT between 2021-2024. Clinical and pathological data including histological subtype, WHO/ISUP grade, and sarcomatoid differentiation were recorded. Metabolic parameters extracted included SUVmax, SUVmean, SUVpeak, TLG, MTV, and delayed SUV metrics. Texture analysis of FDG PET images was performed using LIFEx v7.6, extracting 110 second- and third-order radiomic features following IBSI guidelines. Radiomic features underwent univariate screening with false discovery rate correction, followed by LASSO-based feature selection to construct multivariate logistic regression models. Model performance was assessed using AUC, sensitivity, specificity, and accuracy.

Results

The cohort included 17 males and 10 females (mean age 56.9±11.2 years), predominantly clear cell RCC (74.1%). Grade 1 tumors comprised 59.3%, and sarcomatoid differentiation was present in 33.3%. Papillary subtypes showed markedly higher SUVmax compared to clear cell (p < 0.05). TLG demonstrated strongest association with sarcomatoid differentiation (p=0.007, Cohen’s d=0.713), outperforming SUV-based parameters. PET based texture features discriminated histological subtypes: GLRLM Short Run Low Grey Level Emphasis and NGTDM Coarseness were higher in non-clear cell versus clear cell RCC (p=0.036). Univariate screening identified NGTDM ‘Busyness’, GLCM ‘Contrast’, GLSZM ‘Zone Size Non-Uniformity’, and GLRLM ‘Run Length Non-Uniformity’ as markers of sarcomatoid differentiation. Multivariate signatures integrating complementary features achieved AUCs of 0.91, 0.96, and 0.89 for high-grade, sarcomatoid, and metastatic disease respectively, with sensitivities and specificities >85%.

Conclusion

Radiomics offers complementary insights among RCC patients with FDG PET based texture indices capturing intratumoral heterogeneity with greater precision. Combining metabolic with radiomic metrics, overcome the limitations of conventional FDG PET analysis and therefore enables a powerful, non-invasive strategy for characterizing tumor grade, sarcomatoid differentiation, and metastatic risk, guiding clinical management.

ABAOCNMB196: Dynamic ¹⁸F-FDG PET/CT as a Non-Invasive Tool for Evaluating Muscle Invasion in Bladder Cancer: A Feasibility Study

Ramkumar Elumalai, Koramadai Karuppasamy Kamaleshwaran

Kovai medical center and hospital

Introduction

Accurate identification of muscle invasion in urothelial carcinoma of the urinary bladder is crucial, as it determines treatment between organ-sparing and radical modalities. Multiparametric magnetic resonance imaging (mpMRI) remains the reference standard, but may be limited in patients with contraindications or post-transurethral resection of bladder tumour (TURBT) inflammatory changes. ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is widely used for metastatic evaluation, but its role in local tumour (T) staging has been restricted by intense urinary tracer activity. Early dynamic imaging aims to capture tumour perfusion before urinary tracer interference, potentially improving local staging accuracy.

Aim

To evaluate the diagnostic accuracy of early dynamic ¹⁸F-FDG PET/CT in detecting muscle invasion, using histopathology as the reference standard and mpMRI as a comparator.

Materials and Methods

This prospective study included 66 patients (47 males, 19 females; mean age 60 ± 11 years) with histopathologically confirmed urothelial carcinoma who underwent early dynamic ¹⁸F-FDG PET/CT and mpMRI. A 10-minute pelvic dynamic acquisition was performed immediately after tracer injection and reconstructed into five 2-minute frames (SUVmax1–SUVmax5). Muscle invasion on PET/CT was defined by an early (0–2 min, Suvmax1) increase and consistent rise in SUVmax across frames. SUVmax values were compared between muscle-invasive (MIBC) and non-muscle-invasive (NMIBC) tumours and correlated with histopathology.

Results

Of 66 patients, 22 (33 %) had MIBC and 44 (67 %) NMIBC. MIBC demonstrated significantly higher early uptake (SUVmax₁: 5.6 ± 1.3 vs 1.8 ± 0.9; p < 0.001) and rising time–activity curves compared with NMIBC. Delayed SUVmax was also higher in MIBC (14.3 ± 4.4 vs 5.9 ± 1.9; p < 0.001). Receiver operating characteristic (ROC) curve analysis for early dynamic ¹⁸F-FDG PET/CT yielded an area under the curve (AUC) of 0.93, with an optimal SUVmax₁ threshold of 4.6 providing sensitivity 86 % and specificity 91 %. mpMRI showed comparable performance (sensitivity 91 %, specificity 88 %, accuracy 89 %; κ = 0.78). Inter-observer agreement for SUVmax measurement was excellent (intraclass correlation coefficient = 0.92).

Conclusion

Early dynamic ¹⁸F-FDG PET/CT effectively identifies muscle invasion in bladder cancer by capturing perfusion-driven tracer kinetics before urinary activity interferes. It provides a practical, non-invasive adjunct to mpMRI and offers a potential “one-stop” staging solution, especially in MRI-ineligible patients.

ABAOCNMB177: Optimal imaging time for 68Gallium-PDL1 Positron Emission Tomography/Computed Tomography: a time-point comparison of PDL1 status assessment in lung malignancy

Divya Velu, Indrani Muthukrishnan, Dinesh Kumar Gauthaman, Shelley Simon

Apollo Hospitals

Aim

This study aims to compare the image resolution and tracer uptake of 68Ga- Programmed Cell Death Ligand 1 (PDL1) Positron Emission Tomography/Computed Tomography (PET/CT) scans acquired at different time points to determine the optimal imaging time for PDL1 status assessment in non small cell lung malignancy.

Materials and Methods

This prospective, observational study included ten patients with biopsy-proven primary lung malignancy. Each patient underwent two scans: a 68Gallium-PD-L1 PET/CT and an 18F-FDG PET/CT, performed on different days. Image interpretation involved both visual analysis and quantitative assessment using the maximum standardized uptake value (SUVmax) to compare the 68Ga-PDL1 uptake across the different time points with the corresponding 18F-FDG uptake. SUVmax at 4 different time points (30 minutes, 1 hour, 1 hour 30 minutes and 2 hours post-injection) were calculated for tumor, liver, spleen, kidney and aorta and the values were compared and correlated to arrive at a conclusion regarding the best time point for PDL1 imaging.

Results

Of the ten patients included in the study there were seven male and three female patients; mean age: 62 years, all ten had biopsy proven primary lung malignancy. In these patients, the mean SUVmax values in the tumor at 30 minutes, 1 hour, 1 hour 30 minutes and 2 hours post-injection were 5.3, 6.1, 9.35 and 8.6 respectively. Based on the highest tumor-to-background ratio and visual resolution, the best image quality and results were obtained at 1 hour 30 minutes post injection.

Conculsion

Imaging at 1 hour 30 minutes post-injection appears to be the optimal time point for 68Ga-PD-L1 PET/CT, providing the best image resolution and highest tumor-to-background contrast for assessing PD-L1 expression in lung malignancy.

ABAOCNMB225: EXTERNAL VALIDATION OF THE CHRISTIE FDG PET/CT SCORING SYSTEM AND COMPARATIVE EVALUATION WITH THE HOPKINS CRITERIA FOR POST-TREATMENT RESPONSE ASSESSMENT IN HEAD AND NECK SQUAMOUS CELL CARCINOMA: EVIDENCE FROM A REAL-WORLD INDIAN COHORT

AYAN DHIMAN, SULOCHANA SARSWAT, RAMAN MANOJKUMAR TOSHNIWAL, ABHINAV SINGHAL, NISHIKANT A. DAMLE, AMAN SHARMA

Department of Nuclear Medicine, A.I.I.M.S, New Delhi

Background

Visual response assessment criteria such as the Hopkins and Christie scores are widely used for FDG PET/CT interpretation after definitive therapy in head and neck squamous cell carcinoma (HNSCC). While the Hopkins criteria are well-validated, evidence for the Christie system remains limited, especially in high-background uptake populations. This study aimed to externally validate the Christie score against actual clinical outcomes and to compare its performance and concordance with the Hopkins criteria in an Indian cohort.

Methods

Sixty-seven post-treatment HNSCC patients were retrospectively analyzed. FDG PET/CT scans were scored using the three-point Christie scale (1 = complete metabolic response, 2 = indeterminate/minimal uptake, 3 = residual or progressive disease) and the five-point Hopkins scale (1–5). Final outcomes were categorized as complete metabolic response (CMR), partial response (PR), or progressive disease (PD) based on clinicoradiologic follow up. Statistical evaluation included Chi-square and Fisher’s exact tests, Cohen’s κ, quadratic weighted κ, Spearman and Kendall correlations, and ordinal logistic regression.

Results

Christie score distribution: 1 (n = 3), 2 (n = 25), 3 (n = 39); outcome distribution: CMR = 39, PR = 25, PD = 3.

Christie score showed poor-to-fair concordance with actual outcomes (Cohen’s κ = 0.15, 95% CI 0.06–0.25; weighted κ = 0.31; accuracy = 37%). Nevertheless, there was a significant association between Christie category and outcome (χ²[4] = 19.4, p = 0.0006). Ordinal regression confirmed a significant trend toward worsening outcomes with higher Christie scores (β = 2.61 ± 0.69, p < 0.001; OR = 13.7 per step increase). Fisher’s exact test (Christie 2 vs 3) showed 13-fold higher odds of non-CMR for Christie 3 (p < 0.0001).

Mapping Hopkins to Christie (1↔1, 2–3↔2, 4–5↔3) yielded substantial agreement (Cohen’s κ = 0.595, weighted κ = 0.661, r = 0.653; p < 0.0001) with 79% accuracy. Predictive performance was comparable: Christie—sensitivity 0.89, specificity 0.64; Hopkins—sensitivity 0.86, specificity 0.67.

Conclusion

In this external validation, the Christie score demonstrated only fair concordance with true post-treatment outcomes on FDG PET/CT but retained a strong ordinal association with response category. The system effectively differentiates favorable (CMR) from unfavorable (PR/PD) outcomes but lacks precision for individual classification. In the HNSCC patients, post-radiotherapy inflammatory uptake is frequent, and reliance on Christie scoring alone may overestimate residual disease. A multiparametric approach integrating metabolic, volumetric, and clinical parameters is recommended to enhance response assessment reliability.

ABAOCNMB244: TAGUCHI-BASED OPTIMIZATION OF SPECT ACQUISITION PARAMETERS USING JASZCZAK PHANTOM

Ibtesham Kausar, Poovendhan Mathiyazhagan, Nandini Pandit

JIPMER

Introduction

Optimization of Single Photon Emission Computed Tomography (SPECT) acquisition parameters is essential to balance image quality with scan efficiency, yet conventional trial-and-error methods are resource-intensive. This study applies a Taguchi design-of-experiments (DOE) framework to establish robust reference calibration and derives optimal combinations beyond experimentally tested configurations through main effects analysis.

Aims

To identify optimal combinations of matrix size, projections per head, time per projection, and iterations at a reference count rate using Taguchi analysis.

Materials and Methods

Experiments were performed on GE Discovery NM 630 with a LEHR collimator. A Jaszczak SPECT phantom was filled with Technetium-99m solution to yield approximately 10 kilocounts per second in the Tc-99m photopeak window with 20 percent energy window. An L9 orthogonal array was implemented with four factors: matrix size (64/128/256), projections (60/90/120), time per projection (10/20/30 seconds), and iterations (2/4/8), requiring nine acquisitions. Images were reconstructed using ordered subset expectation maximization with ten subsets. Image-quality metrics included sphere score, rod score, and root mean square noise. Composite signal-to-noise ratios and main effects analysis determined factor influence and predicted optimal combinations.

Results

Main effects analysis revealed time per projection and matrix size as the most influential factors. Three optimal protocols were derived:

First, the maximum quality protocol using 128×128 matrix, 60 projections, 30 seconds per projection, and 4 iterations achieved the highest image quality in 30 minutes.

Second, the balanced protocol using a 128×128 matrix, 60 projections, 20 seconds per projection, and 4 iterations achieved 33 percent time reduction while maintaining diagnostic quality.

Third, a time-efficient protocol using a 128×128 matrix, 60 projections, 10 seconds per projection, and 4 iterations achieved 67 percent time reduction meeting minimum diagnostic thresholds.

Conclusion

The Taguchi method enabled derivation of optimal SPECT parameters requiring only nine acquisitions instead of 81 full factorial experiments. Three validated protocols address varying clinical priorities: maximum quality for complex cases, balanced performance for routine workflow, and rapid throughput for high-volume departments. This systematic approach provides flexible scanning strategies while maintaining diagnostic quality standards.

ABAOCNMB047: Totally indigenous ^99mTc--HYNIC-PSMA SPECT/CT vs Tc-99m-MDP + CECT-TAP in the initial staging of prostate carcinoma: a pilot study

Arvind Suresh, Varun Shukla, Manikandan MV, Swayamjeet Satapathy, Sashank Saini, Nilendu Purandare, S. N. Singh, Sonali Thakur, Himanshu Pandey, Ajish Kumar, Sweety Mittal, Madhava B Mallia

Department of Nuclear Medicine and Molecular Imaging, Mahamana Pandit Madan Mohan Malaviya Cancer Centre and Homi Bhabha Cancer Hospital (MPMMCC and HBCH, units of Tata Memorial Centre, Mumbai), India and Homi Bhabha National Institute, Trombay, Mumbai, India,

Aim

Compare efficacy of ^99mTc-HYNIC-PSMA, [from lyophilized indigenously produced HYNIC-PSMA, hereafter HPSMA] SPECT/CT vs ^99mTc-MDP (hereafter MDP) + CECT (current standard of care for prostate cancer staging).

Methods

13 prostate cancer patients [Gleason score 4+3=7 and above] and PSA levels >10 ng/ml were screened between April-November 2024. Selected 9 patients underwent HPSMA scan and MDP scan 2-3 days later. Both scans involved intravenous injection of 740 MBq of respective tracers followed by planar and SPECT/CT scan for HPSMA after 3-4 hours. CECT was taken alongside HPSMA scans. Lesions identified in each modality were analyzed as a combination of CECT+MDP vs HPSMA.

Results

For 9 patients with Gleason scores 7-10, the median baseline PSA was 256 ng/ml [33.96-1810]. Primary was detected on 99mTc-HYNIC PSMA SPECT/CT and CECT independently in all cases. Lobe localization in 4/9 and seminal vesicle involvement in 8/9 patients. Median SUVmax of prostatic lesions was 22.592 [9.3-36.51]. 8/9 patients had detectable nodes on CT with HPSMA uptake, median short axis (SA) of 13.5 mm [8-71 mm] and median SUVmax of 18.7 [8.47-41.65]. 5/9 patients had 1-7 nodes < 1 cm with median SUVmax of 4.8 [2.55-9.98]. 7/9 patients had sclerotic bony metastases; median of 14 [3-50], 27 [6-64] and 32 [9-78] discrete lesions detected in CECT, MDP and HPSMA scans respectively. 1 patient had lung metastases, where 14 were detected on CECT, 7 had HPSMA uptake (SUVmax 5.38). CECT+MDP detected median of 37 lesions [1-67] vs HPSMA scan detected a median of 51 [1-81] in the same patient. HPSMA/CECT and MDP scans required 2 working days with a gap of 2-3 days in between.

Conclusion

Indigenously produced ^99mTc-HYNIC-PSMA SPECT/CT can detect more lesions than CECT+MDP combined and provide SUVmax values for the lesions similar to ⁶⁸Ga-PSMA-11 PET/CT(1) [not feasible in either CECT or MDP scans]. Though ^99mTc-PSMA kits are available elsewhere (1–3), indigenous production of PSMA-ligand and the development of a freeze-dried kit at BARC is a significant step towards affordable prostate cancer diagnosis in India (4). It provides image quality similar to ⁶⁸Ga-PSMA-11 PET/CT and therefore utilizable as an alternative for staging, monitoring and surveillance of patients with prostate cancer who can’t afford/have access to ⁶⁸Ga-PSMA-11 PET/CT. ⁹⁹Mo/^99mTc-generators are common and affordable to most Nuclear Medicine centers in India compared to the ⁶⁸Ge/⁶⁸Ga- generators. Further studies are needed to assess its full utility in patients with prostate cancer.

ABAOCNMB055: Diagnostic performance of 68Ga-FAPI-46 PET/CT in gastric adenocarcinomas: A retrospective analysis

Simran Kalra, Yash Jain, Manikandan Venkatachalam, Arvind Suresh, Mayank Tripathi, Akhil Kapoor, Lincoln Pujari, Zachariah Chowdhury, Sonali Thakur

Homi Bhabha Cancer Hospital and Research Centre, Tata Memorial Centre

Introduction

Gastric adenocarcinoma remains one of the most common and deadly malignancies worldwide, often presenting at an advanced stage and requiring accurate staging for optimal management. Gastrointestinal (GI) malignancies, which often exhibit a desmoplastic reaction with a high density of Fibroblast Activation Protein (FAP) expressing cancer associated fibroblasts (CAFs), are particularly well-suited for 68Ga FAP inhibitor (FAPI)-46 PET/CT. 68Ga-FAPI-46 PET/CT is a novel molecular imaging modality that targets CAFs, which are abundantly expressed in gastric adenocarcinoma. This study aims to evaluate the diagnostic performance of 68Ga-FAPI-46 PET/CT in gastric adenocarcinomas

Aims and Objectives

Primary: To evaluate the sensitivity of 68Ga-FAPI PET/CT in the Gastric Adenocarcinomas.

Secondary: To assess the incidence of loco-regional, peritoneal and distant metastases and to assess the correlation of uptake between different histopathological subtypes of gastric adenocarcinoma.

Materials and Methods

We retrospectively evaluated 34 patients with histologically proven Gastric adenocarcinoma for initial staging and each patient underwent 68Ga-FAPI-46 PET/CT imaging to determine the detection rate of primary lesions, nodal, peritoneal and distant metastases. The uptake intensity and distribution of FAPI in primary tumors and metastatic lesions were assessed by standardized uptake value (SUVmax). Sensitivity for tumor detection and staging were calculated using histopathological and/or clinical follow as the reference standard.

Results

The mean age group of patients included in the study was 56.9 + 13.6 years. There were 15 females and 19 males. All 34 patients were histologically proven with gastric adenocarcinoma out of which, 8 Poorly differentiated adenocarcinoma (PDAC), 13 Moderately differentiated adenocarcinoma (MDAC), 2 Well differentiated adenocarcinoma (WDAC), 7 poorly cohesive, 3 Signet ring cell cancer (SRCC), 1 Intramucosal adenocarcinoma (IMAC). Only primary disease was detected in 12 patients, primary with loco-regional disease in 7 patients, peritoneal and distant metastases in 12 and 10 patients respectively. 68Ga-FAPI-46 PET/CT demonstrated excellent sensitivity (100%) for detecting primary gastric tumours. Mean SUVmax of primary tumors, peritoneal disease and metastases was 13.30, 7.78 and 9.35 respectively. The distribution of SUVmax was not different among different categories of histology (p value 0.41), thus indicating that uptake of 68Ga-FAPI PET/CT is not dependent on the histopathological subtype of the gastric adenocarcinoma.

Conclusion

Our findings indicate that 68Ga-FAPI-46 PET/CT is highly sensitive in the evaluation of primary gastric adenocarcinoma, lymph nodes and distant metastasis.

In addition, 68Ga-FAPI-46 PET/CT showed detection of peritoneal disease and metastatic lesions with high tumor-to-background ratio. Lesion delineation was sharper, providing better visualization for treatment planning. Poorly differentiated and mucinous tumors, which often shows low FDG uptake, demonstrated high FAPI tracer distribution.

ABAOCNMB056: Instant noodles as a standardized, vegetarian alternative meal for gastric emptying scintigraphy

Kushagra Jain, Abhinav Jaimini

Institute of Nuclear Medicine and Allied Sciences (INMAS), Delhi, India

Objectives

The gastric emptying study commonly uses an egg-white sandwich as the standard meal. However, challenges arise in patients who are vegetarian, allergic to eggs, or unwilling to ingest eggs. Moreover, variability exists in the meal contents and preparation procedures across centers. Therefore, an alternative meal is required that is widely acceptable, easy to procure, has uniform composition, and can be prepared using a standardized method. Instant noodles, being vegetarian, widely available, uniform in content, and quickly prepared, were evaluated as a potential substitute for egg meals in gastric emptying scintigraphy.

Methods

Instant noodles were radiolabeled using two techniques: post-cooking adsorption and intra-cooking absorption. Both Technetium-99m (99mTc) and 99mTc–sulfur colloid (99mTc-SC) were tested. In-vitro stability was assessed by incubating labeled noodles in simulated gastric fluid (pepsin + HCl) at 37 °C. Tagging efficiency was measured at baseline and after 2 hours using centrifugation and filtration.

Results

Maximum labeling efficiency was observed with 99mTc-SC using the intra-cooking method (96.9%). After 2 hours, retained activity remained satisfactory, with 99mTc-SC showing the best stability (up to 80.9%). Both adsorption and absorption techniques achieved acceptable efficiencies, with consistently higher values for 99mTc-SC compared to plain 99mTc.

Conclusions

Radiolabeled instant noodles demonstrate excellent tagging efficiency and appreciable in-vitro stability, suggesting their suitability as an alternative standardized solid meal for gastric emptying scintigraphy.

ABAOCNMB067: DIAGNOSTIC PERFORMANCE AND SURGICAL UTILITY OF 11C-CHOLINE PET/CT IN PRIMARY HYPERPARATHYROIDISM WITH NEGATIVE CONVENTIONAL IMAGING

Shrikant Verma, Sukanta Barai, Aftab Hasan Nazar

SGPGIMS LUCKNOW

Aims

Diagnostic performance and surgical utility of ¹¹C-Choline PET/CT in Primary Hyperparathyroidism with Negative Conventional Imaging

Introduction

Hyperparathyroidism is a metabolic disorder characterized by the excessive production of the parathyroid hormone. The diagnosis is based on clinical and laboratory data. In most cases the only treatment is surgery and accurate preoperative localization of parathyroid adenomas is essential for guiding minimally invasive surgery in primary hyperparathyroidism. Conventional first-line imaging with ultrasound and 99mTc-sestamibi may yield negative or discordant findings. This study evaluated the diagnostic performance of ¹¹C-choline PET/CT as a second-line imaging modality in this clinical setting.

Material and Methods

We conducted an ambispective single-center cohort study including patients with primary hyperparathyroidism who underwent ¹¹C-choline PET/CT between 2023 and 2025 following inconclusive or discordant first-line imaging, and who subsequently underwent parathyroid surgery. PET/CT findings were analysed on a lesion-based level, with surgical exploration and histopathology serving as the reference standard.

Results

18 patients were included. ¹¹C-choline PET/CT detected 19 suspected lesions, of which 17 were surgically confirmed as pathological parathyroid glands. Focused parathyroidectomy was achieved in 16/18 patients (89%), while 1 patient required cervical exploration due to an ectopic adenoma. On a per-lesion basis, sensitivity, positive predictive value, and accuracy of ¹¹C-choline PET/CT were 100%, 89%, and 90%, respectively.

Conclusions

In patients with Primary Hyperparathyroidism and inconclusive or discordant first-line imaging, ¹¹C-choline PET/CT provides precise localization of pathological parathyroid glands with high diagnostic accuracy, facilitating minimally invasive surgery and potentially reducing the need for bilateral cervical exploration.

ABAOCNMB064: Labeling Efficiency and Stability of Terbium-161 based radiopharmaceuticals – early experience

Saranya Thiruvengadam, Indirani Elangovan, Dinesh kumar Gauthaman, Shelley Simon

Department of Nuclear Medicine, Apollo Hospitals, Chennai

Background

Terbium-161 (Tb-161) is a novel radionuclide in theranostics. The presence of Auger and conversion electrons, and similar chemical properties of Lutetium-177 (Lu-177) makes it an ideal radionuclide for therapy in metastatic cancers, resistant to Lu-177 therapy. The aim of this study is to assess the labeling efficiency and stability of Tb-161 based radiopharmaceuticals prepared in house.

Material and Methods

This prospective observational study included 6 Tb-161 labeling procedures – 4 PSMA, 1 DOTATATE, 1 FAPI. Peptide was added to the buffer mixture (Sodium acetate anhydrous + acetic acid), 100 ul Ascorbic acid was added to stabilize the pH and after adequate mixing, the final mixture was added to the activity vial containing Tb-161. After heating the mixture for 25 minutes at 95˚ C, the final product underwent quality control (QC) in Thin Layer Chromatography (TLC) scanner using sodium acetate solvent and TLC strip. If the final product passed the QC (> 95%) with single peak, it was ready for clinical use. If the product failed QC (< 95%), 100 ug of peptide was added and subjected to heating for another 10 minutes to achieve 95% QC. The labeled product was stored at room temperature and at cold temperature (2 to 8˚ C) and serial QC were performed at 2 hour intervals, to study the radiopharmaceutical stability.

Results and Discussion

Three procedures required additional peptides for achieving > 95% QC. At room temperature, the labeling of Tb-161 radiopharmaceuticals maintained till 6 hours post preparation, with appearance of double peak in TLC scan at 8 hours. At cold temperature the labeling lasted for 8 hours post preparation, with appearance of double peak in TLC scan at 10 hours.

When the product was subjected to reheating after appearance of double peak in TLC scan at room and cold temperatures, it passed the QC again. However, further serial tests were not performed to analyze the stability of the product again.

Conclusion

Tb-161 requires relatively more peptide for labeling, when compared to Lu-177. The stability of Tb-161 is shorter when stored at room and cold temperature. We hypothesize that the additional Auger and conversion electrons may contribute to earlier radiolysis in Tb-161. Hence, QC protocol must be strictly followed when using Tb-161 based radiopharmaceuticals. Further studies on stability of Tb-161 based radiopharmaceuticals in deep freeze temperature are warranted, to compare the stability of Tb-161 with Lu-177 based radiopharmaceuticals.

ABAOCNMB081: Atypical Dementia: Insights from FDG PET patterns

Chakshine S, Madhavi Tripathi, Nishikant Avinash Damle, Aakash Aravindh Murugan, Bhabani Shankar Nayak, Anu Gupta, C.S. Bal.

Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi

Aims

To characterize atypical metabolic patterns in clinically diagnosed variant dementia syndromes using F-18 Fluorodeoxyglucose Positron Emission tomography (FDG-PET) and highlight its role in identifying both the neurodegenerative and potentially treatable causes of cognitive impairment.

Materials and Methods

A retrospective analysis of 240 patients with clinically suspected atypical dementia was conducted, who underwent FDG PET for cognitive impairment. Demographic data, clinical data and FDG PET findings were recorded. Cases were grouped into atypical Alzheimer’s Disease (AD), Frontotemporal Dementia (FTD) spectrum [semantic variant primary progressive aphasia (svPPA), non-fluent/agrammatic variant (nfvPPA)], Parkinsonism-plus syndromes [Progressive Supranuclear Palsy (PSP), Corticobasal Syndrome (CBS), Multiple System Atrophy (MSA)], Parkinson’s Disease Dementia (PDD), vascular dementia, prion disease, mixed dementia (AD + vascular) and reversible causes [Autoimmune Encephalitis (AIE), Normal Pressure Hydrocephalus (NPH), CNS Lymphoma). FDG PET metabolic patterns were analyzed for atypical signatures, focusing on region specific hypometabolism /hypermetabolism, and laterality (symmetry vs asymmetry) and correlated with clinical data to improve diagnostic confidence.

Results

Conclusion

FDG PET not only reinforces its clinical utility in the assessment of atypical dementia, but also plays a vital role in identifying potentially treatable causes, thereby facilitating timely interventions that may significantly improve patient outcomes. Recognition of symmetry versus asymmetry further refines differential diagnosis, highlighting FDG PET as a pivotal tool for integrating metabolic signatures into clinical decision making.

ABAOCNMB113: ⁶⁸Ga-NODAGA-RGD PET-CT imaging in patients of Peripheral vascular diseases (PVD)

Vishwajeet Jadhav, Priyanka Verma, Sandip Basu, Pravin Shinde, Dev Adhikari, Ashok Chandak

RMC, BARC

Introduction and Aim

Peripheral vascular disease (PVD) is one of the prevalent vascular conditions and it frequently coexists with vascular disease in other parts of the body. Early diagnosis is important for improving the patient’s quality of life and for reducing the risk of serious secondary vascular events. The study aimed to demonstrate the uptake/expression of RGD-binding integrins in PVD patients using ⁶⁸Ga-NODAGA-RGD PETCT.

Materials and Methods

This was a prospective study between January 2023 to October 2024 recruiting patients with suspected PVD (Clinical/US Doppler or CT angiography). The study was approved by the Institutional Ethics Committee. 2 – 3 mCi of ⁶⁸Ga-NODAGA-RGD tracer was injected intravenously, followed by a 60-minute uptake period. PET scan was performed from base of skull to the toe region. In addition to observing the uptake on ⁶⁸Ga-NODAGA-RGD PETCT, the findings were correlated with USG Doppler study and clinical findings.

Result

A total of 30 patients, 7 females, and 23 males were enrolled in the study with ages ranging from 22 years to 87 years (median age 54.5 years). Out of 30 patients, 25 cases were of PVD (peripheral vascular disease), 4 cases were of varicose vein and one case of thrombosis of major vessels due to malignant lung mass. ⁶⁸Ga-NODAGA-RGD expression seen in total of 17/30 patients and no expression seen in 13/30 patient. Out of 17 patients who showed ⁶⁸Ga-NODAGA-RGD uptake, 13 patients were true positive (TP). 13 cases were true negative (TN) and 4 were false negative (FN). There were no false positives (FP) on ⁶⁸Ga-NODAGA-RGD PET-CT. ⁶⁸Ga-NODAGA-RGD expression correlated with clinical finding of gangrene in 11 cases, out of which 9/11 were TP and 1/11 was TN and 1/11 was FN. ⁶⁸Ga-NODAGA-RGD correlated with characteristic monophasic waveform pattern on US Doppler in 14 patients. Out of these 14 patients, 12/14 were TP and 2/14 were TN. The overall sensitivity and specificity of ⁶⁸Ga-NODAGA-RGD PET-CT were 76.47% and 100% respectively. The positive predictive value (PPV) and negative predictive value (NPV) of ⁶⁸Ga-NODAGA-RGD were 100% and 76.47% respectively along with accuracy of 86.67%.

Conclusion

The results showed a significantly good sensitivity, specificity and positive predictive value of 100%. The result suggests that ⁶⁸Ga-NODAGA-RGD can be used as a neovascularization marker in cases of PVD. RGD binding integrin molecule αvβ3 and αvβ5 are expressed in affected vessel of gangrenous limb and also correlates well with USG Doppler. The PET-CT modality can be used to assess the extent of vessel involvement and also as prognostic indicator in cases of PVD. Further studies with larger number of patients are needed to evaluate the treatment response of this modality and to establish an impact in management.

ABAOCNMB090: Targeting αvβ6-Integrin in Pancreatic Cancer: Diagnostic Potential of Gallium-68 Trivehexin PET/CT Compared to F-18 Fluoro Deoxy Glucose PET/CT.

Ahalya S Prasad, Dinesh Kumar Gauthaman, Indirani Muthukrishnan, Shelley Simon

DNB Academic Resident, Apollo Hospital

Introduction and Aims

F-18 fluorodeoxyglucose Positron Emission Tomography/Computed Tomography has long been established as a valuable tool for staging and monitoring pancreatic malignancies. Gallium-68 Trivehexin, a novel PET tracer targeting αvβ6-integrin, a biomarker overexpressed in pancreatic cancer, has shown encouraging preliminary results. Gallium-68 Trivehexin may also open new avenues for theranostic applications in pancreatic carcinoma, given its ability to selectively target αvβ6-integrin. The aim of this study is to compare the diagnostic performance of Ga-68 Trivehexin PET/CT with F-18 FDG PET/CT, in pancreatic adenocarcinoma.

Materials and Methods

This prospective observational study included fourteen patients with either suspected pancreatic malignancy or suspected recurrence of pancreatic malignancy. All fourteen patients underwent Ga-68 Trivehexin PET/CT, followed by F-18 FDG PET/CT on two different days. Visual analysis and quantitative assessment using maximum standardized uptake value (SUVmax) were performed to interpret Ga-68 Trivehexin with F-18 FDG PET/CT. All patients were subsequently followed up with biopsy and/or further investigation results.

Results

Among fourteen patients (seven male and seven female; mean age: 52 years), ten were evaluated for suspected primary pancreatic malignancy, while four were known cases of pancreatic adenocarcinoma who had undergone prior surgery and chemotherapy and were being assessed for suspected recurrence.

In the group with suspected primary pancreatic malignancy, all 10 patients demonstrated abnormal Ga-68 Trivehexin uptake at the primary lesion site, whereas 7 patients showed abnormal uptake in FDG PET/CT (Mean SUV-7.9 in F-18 FDG PET/CT and 7.5 in Ga-68 Trivehexin PET/CT).

Biopsy revealed pancreatic adenocarcinoma in all ten patients.

Of the four patients with suspected recurrence, two demonstrated both Ga-68 Trivehexin and FDG uptake at the surgical bed, correlating with nodular thickening at the surgical site suggestive of recurrent disease. One patient showed a new hepatic lesion with Ga-68 Trivehexin uptake and no FDG uptake, and is on follow up. One patient was negative on both scans.

The mean SUVmax in patients with suspected primary pancreatic malignancy was 6.8 for Ga-68 Trivehexin and 6.0 for FDG. The mean SUVmax for patients with suspected recurrence was approximately 4.5 in Ga-68 Trivehexin PET/CT and 3.5 in F-18 FDG PET/CT.

Conclusion

Ga-68 Trivehexin PET/CT has shown promise in the diagnosis of pancreatic adenocarcinoma, particularly in lesions with low or absent FDG avidity. However, larger studies are needed to validate its diagnostic performance and to further explore its potential role in targeted radionuclide therapy.

ABAOCNMB088: F-18 FDG PET/CT-guided biopsy in indeterminate lesions: experience from a tertiary care centre in India

Aakash Aravindh Murugan, Madhavi Tripathi, Bhabani Shankar Nayak, Geetanjali Arora, Apoorva Tyagi, Vrati Jain, Shivsankar Kanankulam Velliangiri

All India Instititue of Medical Sciences

FDG PET/CT-guided biopsy, malignancy mimickers, discordant lesions and targeted biopsy.

Introduction

Distinguishing malignancy from benign mimickers such as granulomatous, inflammatory, and infectious conditions remains a diagnostic challenge. Conventional imaging modalities mainly depict morphology but not tissue viability, often failing to differentiate viable tissue from necrosis or fibrosis. This limitation may result in sampling errors and inappropriate management. ^18F-FDG PET/CT-guided biopsy integrates metabolic and anatomical information, enabling real-time targeting of viable tissue and improving diagnostic accuracy.

Aims

To assess the efficacy, feasibility and safety of ^18F-FDG PET/CT-guided biopsy in indeterminate lesions.

Materials and Methods

This prospective study included two groups of patients, (a) without prior malignancy but with inconclusive results on conventional imaging, tumor markers, blood cultures, ACE levels and tuberculosis testing, and (b) patients with known malignancy showing new or discordant lesions on surveillance or response assessment PET/CT. Discordant lesions were defined as new FDG-avid foci in atypical sites or appearing despite the primary tumor and known metastases showing good therapeutic response. For all patients, single-bed PET/CT was acquired and transferred to a robotic navigation system (Maxio, Perfint Healthcare) for trajectory planning and guidance. At least three cores were obtained per lesion and processed for histopathology and/or PCR.

Results

77 patients with FDG-avid lesions (42 males, 35 females) were included. Mean injected activity was 2.7 ± 1.5 mCi. Adequate cores were obtained from all targets in a single attempt. Minor bleeding without hematoma formation occurred in 2 patients. Detection rates were 100% in those with known malignancy and 96.9% in those without history of malignancy. PET/CT-guided biopsy showed high diagnostic yield with low complication rates, comparable to conventional image-guided techniques.

Conclusion

^18F-FDG PET/CT-guided biopsy with robotic arm assistance is a safe, feasible, and high-yield technique for resolving diagnostic uncertainties, effectively distinguishing malignancy from benign mimickers and guiding appropriate patient management.

ABAOCNMB083: Pediatric Primary Immunodeficiency Diseases Spectrum of FDG - PET CT Findings.

Alamelu Satish, Indirani M, Shelley S.

Nuclear Medicine and Theranostics Department, Apollo Hospital, Chennai.

Aim

To evaluate the clinical utility of FDG - PETCT in Primary Immunodeficiency Diseases.

Introduction

PID (Primary Immunodeficiency Diseases) patients are susceptible to infections and malignancies; missed on routine investigations due to atypical clinical presentation owing to their aberrant immune system. Patients require earlier diagnosis and swifter treatment. Dependant on Hematopoietic stem cell transplant transplantation (HSCT) for their survival. HSCT renders a immunocompromised patient to reactivation of dormant infections or susceptible to new infections. FDG - PETCT helps in timely diagnosis in these patients.

Materials and Methods

29 PID patients, underwent FDG - PETCT from 2022 to 2025 were included in this retrospective study (range – 4 months to '18 years; female :male = 3 : 27). Patients were classified into following groups based on clinical indications: PUO – 9, Pre HSCT – 14, Post HSCT evaluation -4, Suspected Lymphoproliferative disease - 2. Clinical follow up (minimum period of 6 months and upto maximum of 4 years) and histopathology (wherever available) were considered as reference standards.

Results

In 29 patients, 1 patient was lost to follow up. FDG - PETCT confirmed no active infections in 17 % (5/ 28) of cases that were sent as a part of routine Pre – Transplant evaluation. FDG - PETCT helped to uncover underlying pathology in 21 % (6/ 28) patients, that were not suspected clinically (3 – opportunistic infections, 1 – Chronic Myeloid leukemia, 2 – Inflammatory bowel disease). FDG - PETCT was also helpful in response evaluation post treatment 10 % (3/28) (2 -Disseminated BCGiosis, 1 – Fungal infection).

FDG - PETCT helped to uncover cryptosporidium induced chronic cholangitis in a child with cryptosporidium Ab titre negative, but rising LFT values. In a child suffering from XIAP Syndrome, FDG - PETCT helped in the diagnosis of crohns disease.

Conclusion

FDG - PETCT is an underrated diagnostic tool that should be used in PID patients where clinical acumen and biochemical parameters don’t offer answers.

ABAOCNMB100: Clinical utilization of fluorine-18[¹⁸F]-NAV4694 for imaging amyloid plaques in patients-NIMHANS experience.

Pardeep Kumar^1*, Sandhya Mangalore¹, Venkatesh Murthy¹_, Keerti Sitani¹, Anupama Vajjala², Palanimuthu T Sivakumar².

¹Department of Neuroimaging & Interventional Radiology, ²Geriatric Psychiatry Unit, Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India.

Introduction

Amyloid PET imaging has changed the management of Alzheimer’s disease patients. Several radiopharmaceuticals have evolved in the last two decades. We are reporting the synthesis of the amyloid imaging PET tracer [¹⁸F]NAV4694 in the FX2N synthesis module under GMP-compliant conditions for clinical use.

Methods

The labelling was standardized in the FX2N synthesis module, and the concentration of the precursor was varied from 0.5 to 2.0 mg with a reaction time of 5 to 10 min at 110 °C, followed by hydrolysis with 0.6 M HCl for 5 min. The final purification was standardized with various C18 cartridges to get the maximum yield. All standard quality controls were performed, along with in vivo stability. Briefly, 350 ± 50 MBq of the [¹⁸F]NAV4694 was injected intravenously in patients (n = 30), and PET-MR imaging was performed. The images were processed, and the distribution of the tracer was visually observed in the brain.

Results

A minimum of 2 mg concentration was found to be suitable for radiolabeling at 110 °C for 10 min and purified via C18 plus long cartridge, providing the highest radiochemical yield of 13 ± 3% (decay corrected). The radiochemical purity was 99 ± 0.5 % with a molar activity of 255 ± 125 GBq/µmol. The retention time of the [¹⁸F]NAV4694 was 17.6 ± 0.8 min, which was consistent with the UV/Vis peak of cold NAV4694 at 17.4 ± 0.7 min. The residual solvents, like DMSO and ethanol, were less than the prescribed limit. The HPLC (from plasma) showed no primary metabolites in the plasma, and the stability was 94 ± 2%. The human biodistribution showed a rapid clearance from the blood. The visual analysis showed uptake in cortical grey matter in a positive amyloid scan and in white matter in an amyloid-negative scan.

Conclusion

[¹⁸F]NAV4694 was successfully synthesized in the FX2N synthesis module with high radiochemical purity. It showed distinctive uptake patterns in amyloid-positive and negative scans.

ABAOCNMB092: Impact of Concurrent Chemotherapy on Clinical and Biochemical Outcomes of Lutetium-177 PRRT in Patients with Neuroendocrine Tumours.

Anitha Ramachandran, Indirani Muthukrishnan, Shelley Simon, Dinesh Kumar Gauthaman

Apollo Hospitals

Background

Peptide Receptor Radionuclide Therapy (PRRT) with Lutetium-177-DOTATATE has become an important treatment modality for advanced unresectable neuroendocrine tumours (NETs), enabling targeted delivery of radiation with good response rates and favourable toxicity profile [1]. The NETTER-1 phase 3 trial confirmed its superiority over high-dose somatostatin analogues, showing improved progression-free survival and response rates [2]. However, outcomes vary widely, and concurrent radio-sensitising chemotherapy such as capecitabine and temozolomide has been proposed to enhance efficacy [3-6]. The data on PRRT alone versus in combination remains limited especially in the Indian population. This study aimed to evaluate clinical and biochemical outcomes in standalone versus concurrent chemotherapy and PRRT.

Methods

A retrospective analysis was performed on 53 patients with biopsy-proven NETs treated with Lutetium-177 PRRT at our institution from the year 2020 onwards. Patients were divided into standalone PRRT (n=43) and concurrent chemotherapy + PRRT (n=10). Clinical response was assessed by PET imaging, and biochemical response was evaluated through Serum chromogranin A. Previous treatment history, cycles of PRRT and disease characteristics were analysed.

Results

Across the cohorts, 53 patients- 19(35.8%) achieved stable disease, 15(28.3%) had partial or significant response, 9(16.9%) showed disease progression, and 10 (18.8%) were not evaluable/lost to follow-up.

• In Standalone PRRT (n=43): 14 patients (32.5%) achieved stable disease, 13 (30.2%) had partial or significant responses, 6(10.5%) progressed, and 10 (31.9%) were not evaluable.

• Concurrent chemotherapy + PRRT (n=10): 4 patients (40%) achieved stable disease, 4 patients (40%) had objective responses, and 2 (20%) progressed.

• Comparisons: Combination therapy yielded higher objective response (40% vs. 30.2%) and a higher rate of disease stabilisation (40%). Progression was seen in both groups.

ABAOCNMB148: PILOT STUDY TO EVALUATE THE ROLE OF SOMATOSTATIN RECEPTOR PET-CT IMAGING TO PREDICT EARLY RESPONSE TO BIOLOGICAL THERAPY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Archana Yadav, Arun Ravi John, Avs Anil Kumar

ARMY HOSPITAL, RESEARCH AND REFERRAL

Objectives

Our study intended to determine correlation of Somatostatin Receptor Positron Emission tomography (SSTR PET) parameters to the clinical gold standard of Daily Activity Score 28 - C-reactive protein (DAS28-CRP scores) in patients with Rheumatoid Arthritis (RA) and whether PET parameters can be used for early identification of response to biological therapy in RA patients who are resistant to conventional therapy.

Materials and Method

We recruited twenty-five RA patients who were unresponsive to conventional therapies. Clinical assessments were performed, including 28-point joint evaluation (swollen and tender counts), and CRP measurement to calculate the DAS28-CRP scores. SSTR PET/CT scans were conducted at two time points: before and 6-8 weeks after two doses of Rituximab (1g IV doses, 15 days apart). PET scans measured uptake of ⁶⁸Ga-DOTANOC, with joint uptake scored on a scale of 0-3 (0 -no uptake, 1 - ≥ background but ≤ blood pool, 2 - ≥ blood pool but ≤ liver and 3- ≥ liver), and various PET parameters were recorded: total PET positive joints, Maximum Standardized Uptake Value (SUV max), Cumulative Standard Uptake Value (cSUV), Global score, and Composite SUV index (CI). Global score was calculated by multiplying the total number of PET-positive joints by the highest SSTR PET score. cSUV was the sum of SUV max values for all PET-positive joints, and CI was calculated as cumulative SUV multiplied by the ratio of PET-positive joints to total joints evaluated.

The treatment outcomes were categorized as per the European Alliance of Associations for Rheumatology (EULAR) criteria into “responders” or “non-responders” based on changes in DAS28-CRP scores over six months. Pearson correlation coefficients were used to assess the relationship between baseline PET parameters and DAS28-CRP scores. Chi-Square/Fisher’s exact test compared qualitative variables, while Paired t-test analyzed quantitative variables, with p < 0.05 considered significant. ROC curve identified optimal cut-off for predicting clinical response among the parameters showing statistical significance within the responder group.

Results

Results showed that total PET positive joints, global score, cSUV, and CI exhibited moderate positive correlations with DAS28-CRP, but these correlations were not statistically significant. Among these, cSUV showed the best correlation with DAS28-CRP. Follow-up scans indicated that total PET positive joints, global score, and cSUV showed statistically significant differences between baseline and post-treatment in the responder group. ROC curve analysis revealed that cSUV at 6-8 weeks post-therapy (cut-off ≤ 13.02) was the best predictor of clinical response at six months, with a sensitivity of 75%, specificity of 76.92%, and a positive and negative predictive value of 75% and 76.9%, respectively.

Conclusion

This pilot study suggests that SSTR PET imaging has potential as an early biomarker for predicting treatment response in RA patients undergoing biological therapy. While the findings are promising, further research with larger sample sizes is necessary to validate these results.

ABAOCNMB139: Extraction of Structured Data from Ga-68 PSMA PET/CT Reports using Locally Deployed Artificial Intelligence tools

¹Jagrati Chaudhary, ¹Anil Kumar Pandey, ²Param Dev Sharma, ³Sanjay Kumar, ⁴Kunhi Parambath Haresh, ⁵Chandan J Das, ⁶Ranjit Kumar Sahoo, ⁷Seema Kaushal, ⁸M. Kalaivani, ¹Rakesh Kumar

¹Department of Nuclear Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, India, ²Department of Computer Science, SGTB Khalsa College, University of Delhi, New Delhi, India, ³Department of Urology, AIIMS, New Delhi, India, ⁴Department of Radiation Oncology, AIIMS, New Delhi, India, ⁵Department of Radiodiagnosis & Interventional Radiology, AIIMS, New Delhi, India, ⁶Department of Medical Oncology, AIIMS, New Delhi, India, ⁷Department of Pathology, AIIMS, New Delhi, India, ⁸Department of Biostatistics, AIIMS, New Delhi, India

Introduction

Structured data extraction from Ga-68 PSMA PET/CT reports is crucial for accurate prostate cancer diagnosis, staging, and treatment monitoring (1,2). However, report heterogeneity limits manual and conventional NLP (Natural Language Processing) approaches. Advances in large language models (LLMs) have shown promise in clinical NLP, yet privacy concerns restrict use of cloud-based tools in healthcare. Locally deployable LLMs offer an alternative, but their clinical utility in nuclear medicine remains underexplored (3-5).

Aim

To evaluate the feasibility and accuracy of zero-shot, prompt-based extraction of clinically relevant information from Ga-68 PSMA PET/CT reports using the locally deployed LLaMA 3.2:3B model under realistic clinical conditions.

Materials and Methods

A retrospective analysis was conducted on 132 anonymized Ga-68 PSMA PET/CT reports (2022–2024) from adult males at a single center, following ethical approval. Forty-four standardized clinical queries encompassing primary tumor, nodal and metastatic involvement, lesion quantification, and therapy response were applied. The LLaMA 3.2:3B model, an open-source 3-billion parameter AI tool optimized for secure local deployment, extracted information via zero-shot prompting without fine-tuning. Outputs were validated against manual reference from a nuclear medicine physician. Performance metrics included accuracy, precision, recall, F1-score, and confusion matrices, with domain-specific variability illustrated by bar charts and heatmaps.

Results

Model performance varied by domain. Primary tumor identification was robust (F1=0.99), whereas quantitative measures like SUVmax showed poor accuracy (F1=0.05). Nodal disease extraction was reliable for pelvic and retroperitoneal nodes (F1=0.75–0.81) but suboptimal for supradiaphragmatic nodes (≤0.57). Bone metastases were sensitively detected (recall=0.94), though subtype classification was inconsistent (F1 ≤0.45). Visceral metastasis extraction was limited (mean F1=0.09). Quantitative lesion counts and burden assessments were poorly captured (F1 ≤0.11). Extraction of disease progression (F1=0.82), androgen-deprivation therapy status (F1=0.92), and treatment resistance (F1=0.92) were reliable. Reporting quality indicators such as incidental findings (F1=0.97) and scan adequacy (F1=1.0) were preserved; however, recognition of structured templates was minimal (F1=0.02).

Conclusion

This study demonstrates that the locally deployed AI language models for structured extraction from Ga-68 PSMA PET/CT reports can potentially support clinical tasks including staging, disease monitoring, and report quality assurance. We found limitations in quantitative and rare metastasis characterization. Integration of locally deployed AI tools into nuclear medicine workflows can offer scalable implementations in resource-limited healthcare systems.

ABAOCNMB153: Clinical Impact of Ga68 FAPI PET/CT in Pre-Surgical Staging of Lung Cancer: A Prospective Comparison with FDG PET/CT

Mohit Seth, Partha Choudhury, Laleng Mawia Darlong, Manoj Gupta, Atul Pathak

Rajiv Gandhi Cancer Institute and Research Centre

Introduction / Aims

Lung cancer remains a leading cause of cancer mortality worldwide, and treatment success relies heavily on precise disease staging. FDG PET/CT has long been the standard functional imaging tool, but challenges in distinguishing inflammatory uptake from true malignancy limit its reliability in nodal staging. Ga68 Fibroblast Activation Protein Inhibitor (FAPI) PET/CT has emerged as a promising modality targeting stromal activation within the tumor microenvironment. This study aimed to evaluate the role of Ga68 FAPI PET/CT in staging potentially operable lung cancer and to compare its diagnostic performance and clinical relevance with FDG PET/CT.

Materials and Methods

This prospective study included 16 newly diagnosed, treatment-naïve patients with lung cancer who were considered surgical candidates. Each patient underwent Ga68 FAPI PET/CT and FDG PET/CT within a two-week interval. Tumor uptake, nodal involvement, and disease stage were documented. SUVmax values were recorded and analyzed against mediastinal nodal assessment and/or pathological TNM staging, which served as the reference standard. Receiver Operating Characteristic (ROC) curve analysis was performed, and diagnostic parameters including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated.

Results

FDG PET/CT achieved an area under the curve (AUC) of 0.715 (95% CI: 0.523–0.906; p = 0.023), consistent with moderate diagnostic capability. Ga68 FAPI PET/CT demonstrated an improved AUC of 0.837 (95% CI: 0.713–0.961; p = 0.001), reflecting superior performance. Using SUVmax thresholds of 3.65 for FDG and 3.00 for FAPI, FAPI PET/CT showed higher sensitivity (84.6% vs. 61.5%) while maintaining identical specificity (75.6%). Importantly, FAPI PET/CT also yielded superior PPV (50% vs. 42.1%), NPV (94.4% vs. 87.2%), and overall accuracy (77.6% vs. 72.4%). These findings indicate that FAPI PET/CT provides more reliable information for assessing nodal involvement and determining surgical eligibility.

Conclusion

Ga68 FAPI PET/CT demonstrated greater sensitivity and diagnostic accuracy than FDG PET/CT in staging lung cancer, particularly for nodal evaluation. By providing more dependable pre-surgical staging, FAPI PET/CT may enhance patient selection for surgery and reduce the risk of inappropriate interventions. These results underscore its potential to improve clinical decision-making in lung cancer management. Larger prospective studies are needed to establish its role in routine practice.

ABAOCNMB126: COMPARATIVE DIAGNOSTIC PERFORMANCE OF CT SHORT-AXIS DIAMETER, PET SUVMAX AND STANDARDIZED IMAGING CRITERIA OF PET SCAN FOR NODAL RECURRENCE IN HEAD AND NECK SQUAMOUS CELL CARCINOMA — NODE- AND PATIENT-LEVEL ANALYSIS WITH EVALUATION OF TREATMENT-TO-SCAN INTERVAL EFFECTS

Jayanta Das, Soumendranath Ray, Anirban Mukherjee, Sayantani Sinha, Rashi Goel, Kapila Manikantan, Prateek Vijay Jain, Indu Arun, Pattatheyil Arun

Tata Medical Center

Background

Nodal recurrence after curative treatment for head and neck squamous cell carcinoma (HNSCC) significantly influences prognosis. CT short-axis diameter (SAD) and PET-CT SUVmax are commonly used, but standardized imaging criteria (SICs) are not routinely applied. This study compared diagnostic performance of CT, SUVmax, and various SICs at both patient and nodal levels, and evaluated the effect of treatment-to-scan interval (TTS).

Methods

Patients with treated HNSCC who underwent PET-CT for suspected recurrence with subsequent histopathological confirmation were included. Diagnostic accuracy of CT (SAD ≥1.0 cm), SUVmax, and SICs (Porceddu, Hopkins, Modified Deauville, Cuneo) was assessed. ROC analysis determined optimal SUVmax threshold. Sensitivity and specificity were calculated at patient and nodal levels. TTS effect was analyzed in stratified bins.

Results

Thirty-nine patients (133 nodal stations) were evaluable. SUVmax yielded the best discrimination (AUC 0.85), with an optimal cut-off ≥2.18 providing ~80% sensitivity and 81% specificity. CT SAD >1.0 cm showed moderate sensitivity (~63%) but high specificity (~90%). SICs performed variably; Modified Deauville ≥3 aligned with other systems. SUVmax ≥2.18 cut-off showed consistently higher sensitivity than CT SAD >1.0 cm, with specificity improving after 3 months post-treatment. Treatment-decision analysis revealed one potential overtreatment case with CT alone, but no undertreatment with PET.

Conclusion

Quantitative PET (SUVmax) was superior for nodal recurrence detection, while CT SAD offered high specificity. Timing of PET-CT strongly influenced accuracy, supporting guideline recommendations for delayed post-treatment imaging. Standardized reporting systems require refinement, but SUVmax remains the most robust parameter for clinical use.

ABAOCNMB145: Comprehensive Radiomic Profiling of Primary Prostatic Lesions on PSMA PET-CT: From Diagnosis to Prediction of Aggressiveness and Metastasis

Ralphemerson P, Kanhaiyalal Agrawal, Girish Kumar Parida, Sai Sradha Patro, T Kishan Subudhi, Biswajit Sahoo, Manoj Kumar Das, Pavithra A, Keerthana Kiran Kandula, Sai Tej Reddy

All India Institute of Medical Sciences, Bhubaneswar

Introduction, Aims

Prostate cancer (PCa) is a leading cause of cancer morbidity in men globally. Prostate Specific Membrane Antigen Positron Emission Tomography – Computed Tomography (PSMA PET-CT) has become a standard-of-care for high-risk primary staging and restaging due to its high sensitivity. However, most clinical interpretation relies on qualitative assessment or simple semi-quantitative values (e.g., SUVmax). This retrospective study aimed to determine if quantitative radiomic analysis of primary prostate lesions on PSMA PET-CT can provide deeper insights, specifically to: (1) differentiate benign from malignant lesions, (2) predict tumor aggressiveness (Gleason Grade Group), and (3) predict metastatic (M1) vs. non-metastatic (M0) disease.

Materials and Methods

We retrospectively analyzed 142 PSMA PET-CT studies. From the primary prostate lesions, 134 IBSI-compliant radiomic features were extracted. After eliminating 93 redundant features via correlation analysis, three patient cohorts were established to address each study aim. A consensus of machine learning methods (LassoCV, Random Forest, RFE) was used for robust feature selection. Multivariate models were trained using 5-fold cross-validation, and their performance was compared against models built using conventional clinical and PET metrics (e.g., PSA & SUV).

Results

Out of 142 patients, 121 patients had histopathological reports, of which 108 were malignant and 13 were benign prostatic lesions. For differentiating benign vs. malignant lesions (n=102), a two-feature radiomic signature achieved excellent discrimination with an AUC of 0.953 (0.914-0.991), Sn = 0.865 (0.794-0.936), and Sp = 0.846 (0.650-1.000). For predicting tumor aggressiveness (n=79), a single radiomic feature yielded good predictive power [AUC: 0.743 (95% CI: 0.603-0.875), Sn (Aggressive PCa): 0.884 (95% CI: 0.795-0.965), Sp: 0.618 (95% CI: 0.392-0.814)], with the feature showing a statistically significant difference between aggressive and non-aggressive groups (p<0.001). However, for predicting metastatic disease (n=115), the radiomic signature was not predictive (AUC = 0.636). A simpler model using three conventional features (serum PSA, sMTV, and TLG) performed significantly better for predicting metastasis [AUC of 0.814 (95% CI: 0.724-0.899)], and the addition of radiomic features did not improve this model’s performance.

Conclusion

Radiomic analysis of PSMA PET-CT demonstrates strong performance in differentiating benign from malignant prostatic lesions and offers a fair prediction of tumor aggressiveness. While conventional metrics (PSA, sMTV, TLG) remain superior for predicting systemic metastatic spread, radiomic texture features appear to be independent predictors of the tumor’s local biological characteristics. This suggests radiomics can serve as a non-invasive “virtual biopsy,” complementing standard PET metrics to provide a more comprehensive characterization of prostate cancer.

ABAOCNMB150: Role of FDG PET/CT in restaging following Neoadjuvant therapy for Esophageal cancer: A Retrospective Analysis.

Tulsi Das, Pk Pradhan, Aftab Hasan Nazar, Manish Ora

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow

Introduction

In patients with locally advanced esophageal cancer (EC), preoperative chemotherapy or radiotherapy has been shown to improve outcome with respect to survival. The most common methods for staging esophageal cancer are endoscopic ultrasonography (EUS) and computed tomography (CT). 18 Fluro deoxy glucose positron emission tomography/ computed tomography (FDG PET/CT) can provide functional information and is an effective diagnostic modality in esophageal cancer. Its role in the management of esophageal cancer includes staging as well as potential utility in the evaluation of neoadjuvant therapy response and in follow up after definitive therapy.

Material and Methods

This retrospective study includes 27 patients (mean Age: 56.3 years; range: 39-78) diagnose with EC. FDG PET/CT was performed post neoadjuvant therapy (NAT) to assess response and restaging of disease. Based on PET/CT findings, patients were classified into disease categories involving no active disease, residual at primary site (locoregional disease), distant metastasis or combination of these. The result of restaging after NAT divides EC patients into three groups, i.e., patients with (I)no evidence of residual disease, who might benefit from an active surveillance approach; or (II) persistent locoregional disease with no evidence of distant spread, who require subsequent surgery; or (III) either persistent or no locoregional disease (LRD) with evidence of distant spread, who should be offered systemic treatment, mostly with palliative intent.

Results

Of the 27 patients, 3 patients had no evidence of residual disease on FDG PET/CT. Ten patients had uptake limited to locoregional disease, in which 4 shows uptake only in primary tumor, 5 patients had both primary tumor and locoregional lymph node positivity and only 1 patient had positive locoregional lymph nodes. Distant metastasis was detected in 14 patients in which 12 had both locoregional disease and distant metastases, 2 had only distant lymph node and 9 patients demonstrated disease in all three regions- primary site, nodes and distant sites. Based on these imaging findings, 10 patients who had locoregional disease underwent surgery. The remaining 14 patients, who had either nodal involvement, distant metastases, or multifocal disease, were treat with NAT.

Conclusion

FDG PET/CT provides critical insight into the extent of disease in patients with EC and significantly influences treatment planning. It reliably detects residual, regional and distant, disease that may not be apparent on conventional imaging. Although current surgical guidelines consider FDG PET/CT optional in EC staging, our finding strongly support its routine use to optimize patient selection for curative surgery versus neoadjuvant therapy. FDG PET/CT should be integrated as a standard component in the staging or restaging of EC.

ABAOCNMB164: KIDNEY DOSIMETRY IN MCRPC PATIENTS UNDERGOING LU-177 PSMA THERAPY: INSIGHTS FROM A SINGLE-CENTER STUDY.

Richa mishra, aftab hasan nazar, p.k. Pradhan, sukanta barai, manish ora, amitabh arya

Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow U.P

Introduction

Lutetium-177 (Lu-177) PSMA therapy is a promising treatment for metastatic castration-resistant prostate cancer (mCRPC). Given the radiosensitivity of the kidneys, careful kidney dosimetry is critical to ensure patient safety. This study aims to quantify the absorbed doses in the kidneys and assess the variability among mCRPC patients who have received Lu-177 PSMA therapy.

Aim

The objective of this study is to evaluate kidney absorbed doses, residence times, and their correlations with patient characteristics, including Glomerular Filtration Rate (GFR), in mCRPC patients undergoing Lu-177 PSMA therapy.

Methods

This analysis included ten dosimetry records from eight mCRPC patients (mean age: 65.2 ± 8.7 years; mean weight: 68.4 ± 18.7 kg). Patients were treated with Lu-177 PSMA with a mean administered activity of 6357.5 ± 586.7 MBq. Kidney doses (mGy/MBq) and cumulative doses (Gy) were calculated using SPECT/CT-based dosimetry. Residence times were derived from normalized cumulative activity, and baseline GFR was recorded for each patient. Correlations between dosimetry results and patient characteristics such as age, weight, administered activity, and GFR were assessed.

Results

The mean kidney dose was 0.476 ± 0.418 mGy/MBq, and the mean cumulative absorbed dose was 2.62 ± 2.29 Gy. Residence times ranged from 0.78 to 5.69 Bq-hr/Bq. Patient GFR values ranged from 31 to 82 ml/min. A significant outlier was observed in one patient, who received a cumulative dose of 8.97 Gy, corresponding to a prolonged residence time of 5.69 Bq-hr/Bq. Notably, this patient also presented with the lowest GFR in the cohort (31 ml/min), suggesting a potential link between reduced renal function and increased radiopharmaceutical retention. The kidney dose showed a very strong correlation with residence time. An inverse relationship was observed between GFR and residence time, highlighting that lower renal clearance may lead to higher radiation doses to the kidneys.

Conclusion

While kidney doses in patients undergoing Lu-177 PSMA therapy are generally within safe limits, this study highlights significant inter-patient variability. The strong influence of residence time on the final kidney dose underscores the importance of personalized dosimetry. Furthermore, the data suggests that patients with poor renal function, as indicated by a low GFR, may be at a higher risk for prolonged residence times and subsequent nephrotoxicity. This warrants further investigation into using baseline GFR as a predictive factor for tailoring therapy and dosimetry protocols.

ABAOCNMB161: FDG PET/CT in Solitary and Extramedullary Plasmacytoma: Diagnostic Value, Therapeutic Guidance, and Response Assessment

Anisha Bana, Manish Ora, Sukanta Barai, Prasanta Kumar Pradhan

Sanjay Gandhi Post Graduate Institute of Medical Sciences

Introduction

Plasmacytoma is a rare plasma cell dyscrasia predominantly involving middle-aged males. It develops within the skeleton or soft tissue as solitary or multiple masses, without evidence of systemic disease. It is classified into solitary plasmacytoma of bone (SPB) and extramedullary plasmacytoma (EMP). Solitary plasmacytoma is the commoner and has two subtypes: SPB with minimal bone marrow involvement (<10% cells) and SPB with no bone marrow involvement. SPB presents with localised bone in ribs, vertebrae (thoracic> lumbar> cervical), femur, and pelvis. The majority of EMPs (80% to 90%) occur in the head and neck region and the aerodigestive tract. It primarily involves oral cavity, tonsillar fossa, nasal cavity, and paranasal sinuses. These lead to local symptoms, including headache, nasal discharge, dysphagia, sore throat, epistaxis, and nasal obstruction.

Materials and Methods

This is a retrospective study conducted from 2017 to 2025, involving 14 patients (male, 12) with histologically verified plasmacytoma with mean age of 52.72 ± 14.9 (26-73) years. Patients presented with symptoms such as localized bone pain, backache, chest pain, fever, nasal obstruction, headaches, swellings, or abdominal pain. All patients underwent biochemical investigations, including serum free light chains (kappa-83.40±103.43mg/l, Lambda- 205.35 ±630.69 mg/l), kappa/lambda ratios (1.73± 1.69), and beta-2 microglobulin levels (3.60 ±3.27 mg/l). Histopathology of all lesions was suggestive of plasma cell neoplasm. Whole-body FDG PET/CT imaging was performed at diagnosis for pretreatment staging and in follow-up to identify additional lesions and assess treatment response.

Result

The majority of patients (10, 71.4%) had solitary bone involvement, commonly affecting the vertebrae (thoracic (2, 20%), > cervical(1,10%), lumbar), sternum(2, 20%), sacrum(2, 20%) clavicle(1, 10%) and ribs(1,10%). Four of them had extramedullary involvement, commonly affecting the paranasal sinuses and abdomen(portocaval, and mesentery region). On FDG PET/CT mean of these lesions (SUVmax-11.89 ± 7.77). Patients were treated with radiotherapy to the local site as identified on FDG PET/CT, along with targeted chemotherapy or immunotherapy (bortezomib, lenalidomide, and pomalidomide). Treatment response evaluation was done after completion of therapy. Complete metabolic response, partial metabolic response, stable disease, and disease progression were noted in 6 (43%), 5 (36%), 1 (7%), and 2 (14%) patients, respectively.

Conclusion

This retrospective study highlights the utility of FDG PET/CT in evaluating both SBP and EMP. A comprehensive biochemical assessment is essential to ruling out dissemination in the form of multiple myeloma. FDG PET/CT detects metabolically active lesions and guides therapeutic decision-making. End-of-treatment FDG PET/CT facilitates a noninvasive assessment of treatment response and tailors personalized treatment.

ABAOCNMB167: Cracking the Code: SUVmax and SUV ratios on 18F-FDG PET/CT as reliable biomarkers in adrenal lesion characterization

Palivela Dhanusree¹, Althaf ¹, Deepanksha Datta¹, Rajesh Kumar¹

Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, India.

Introduction

The incidental discovery of an adrenal mass—an incidentaloma—is a frequent and challenging clinical problem in oncology, occurring in up to 7% of patients. Distinguishing a benign adenoma from metastatic disease is critical for accurate staging and management, yet conventional imaging often yields indeterminate findings. This study sought to determine the diagnostic utility of semi-quantitative ¹⁸F-FDG PET/CT parameters for reliably differentiating malignant from benign adrenal lesions in patients with known cancer.

Materials and Methods

We retrospectively analyzed ¹⁸F-FDG PET/CT scans from 25 oncology patients (17 male, 8 female; mean age 60.4 years) between 2023- 2025 (2 years), who presented with 31 distinct adrenal lesions. For each lesion, we calculated the maximum standardized uptake value (SUVmax) and the ratio of the lesion’s SUVmax to the mean liver uptake (SUV liver). Histopathology or definitive progression on subsequent imaging or response to treatment served as the reference standard for final diagnosis. Receiver operating characteristic (ROC) analysis was employed to identify optimal diagnostic thresholds.

Results

The patient cohort had a range of primary cancers, predominantly lung (44%), esophageal (12%), and breast (8%) malignancies. On follow up scans, it was confirmed that 18 patients (72%) had adrenal metastases, while 7 (28%) had benign lesions. Metastatic lesions were significantly more metabolically active, demonstrating a higher mean SUVmax (10.6 ± 6.3 vs. 2.9 ± 0.7; p=0.004) and a higher mean SUVmax/SUVliver ratio (3.46 ± 1.9 vs. 1.52 ± 0.85; p=0.016) compared to benign lesions. Malignant lesions were also significantly larger (mean size 3.7 ± 1.7 cm vs. 1.73 ± 0.8 cm; p=0.007). ROC analysis established an optimal SUVmax cutoff of ≥3.8, which provided 95.7% sensitivity and 87.5% specificity for malignancy. A SUVmax/SUVliver ratio threshold of ≥1.12 yielded 91.3% sensitivity and 100% specificity

Conclusion

Semi- Quantitative analysis of ¹⁸F-FDG PET/CT scans using SUVmax and lesion-to-liver SUV ratios delivers high diagnostic accuracy in differentiating adrenal metastases from benign incidentalomas. The application of these thresholds provides a robust, non-invasive tool that can clarify indeterminate findings, improve staging precision, and better inform clinical decision-making for oncology patients. SUV-based biomarkers, thus provide a definitive diagnostic advantage in differentiating benign from malignant adrenal lesions, making them clinically significant in refining oncologic staging and guiding treatment decisions.

ABAOCNMB176: Active surveillance following surgery in low-risk papillary thyroid micro carcinoma: long-term outcomes from a combined retrospective and prospective study

Ahalya S Prasad, Dinesh Kumar Gauthaman, Indirani Muthukrishnan, Shelley Simon

Apollo Hospitals

Introduction

Papillary thyroid micro carcinoma (PTMC), is considered a low-risk malignancy with excellent long-term prognosis. With the increasing detection of PTMC due to improved imaging techniques, the role of active surveillance (AS) after surgery i.e. avoiding routine radioiodine ablation has gained prominence as a management strategy for selected low risk patients. This study aims to evaluate follow-up data of patients with PTMC who were managed with active surveillance after surgical intervention and to analyze rates of tumor progression and disease outcome.

Materials and Methods

This combined retrospective-prospective observational study includes 83 patients with histologically confirmed PTMC with low risk features who came for follow ups to the OPD between 2023 and 2025. Tumors measured ≤1 cm in maximum dimension and had no evidence of nodal involvement, extra thyroidal extension or histological features such as tall cell, diffuse sclerosing, hobnail or solid variants. Clinical records, histopathological reports, and imaging studies during follow up were reviewed to identify cases with regional or distant metastasis. Patients found to have metastatic disease were treated with I-131 therapy, and their clinical outcomes were monitored through serum thyroglobulin (Tg) levels and imaging follow-up.

Results

Of the 83 patients who were on active surveillance (median follow up- 10 years, range: 6 months to 10 years), 4 patients were lost to follow up. Two patients (2.4%) had increased serum stimulated Thyroglobulin post-surgery, and underwent I-131 radioiodine therapy. Four patients (4.8%) had biochemical recurrence on follow up for which they were treated with low dose I-131 radioiodine therapy. On subsequent follow ups, these patients showed no recurrence. One patient (1.2%) had structural recurrence (regional node involvement) on 2nd year follow up and underwent I-131 radioiodine treatment. Two patients (2.4%) had structural recurrence (distant metastases) detected on 1st and 2nd year follow ups respectively with increased Serum Thyroglobulin and received high dose I-131 radioiodine therapy. On follow up of these 2 patients with distant metastases, one showed stable Serum Thyroglobulin whereas the other showed minimal drop in Serum Thyroglobulin.

Conclusion

This study reinforces the role of active surveillance as an effective management strategy for patients with low-risk PTMC. The majority of patients remained stable without requiring aggressive intervention, and those with disease progression were managed with targeted therapy, demonstrating favorable outcomes. This supports the growing consensus that, in appropriately selected patients, routine use of radioiodine ablation may be safely avoided, reducing overtreatment while maintaining good long-term prognosis.

ABAOCNMB162: Clinical utility of Carbon-11 tagged Choline Positron Emission Tomography (PET) for localisation of parathyroid adenoma in patients with inconclusive fist line imaging

Shrikant Verma, Sukanta Barai, Aftab Hasan Nazar

SGPGIMS Lucknow

Introduction

Hyperparathyroidism is a metabolic disorder characterized by the excessive production of the parathyroid hormone. The diagnosis is based on clinical and laboratory data. In most cases the only treatment is surgery and an accurate preoperative localization of parathyroid adenomas is essential for guiding minimally invasive surgery. Occasionally even in the presence of strong clinical and biochemical suspicion, Conventional first-line imaging with ultrasound and ^99mTc-MIBI may fail to localise the adenoma or may yield discordant findings. Positron emission tomography as a technique has inherent higher sensitivity and superior resolution compared to both USG and Tc99m-MIBI and PET imaging using Carbon-11 tagged Choline is currently widely used to localise parathyroid tissue when primary imaging are inconclusive.

Aim

to evaluate the diagnostic performance and surgical utility of ¹¹C-Choline PET/CT in primary hyperparathyroidism with inconclusive or discordant first-line imaging.

Material and Methods

We conducted a retrospective single-centre cohort study including 12 patients with strong clinical and biochemical suspicion of primary hyperparathyroidism who underwent ¹¹C-choline PET/CT between 2023 and 2025 following inconclusive or discordant first-line imaging, and who subsequently underwent parathyroid surgery. PET/CT findings were analysed on a lesion-based level, with surgical exploration and histopathology serving as the reference standard.

Results

Twelve patients with inconclusive ^99mTc-MIBI imaging with high degree of suspicion of biochemical hyperparathyroidism were included. ¹¹C-choline PET/CT detected 8 suspected lesions, of which 7 were surgically confirmed as pathological parathyroid glands. 1 patient could not undergo surgery due to advanced cardiac ailment and remaining 4 patients currently in follow up. Focused parathyroidectomy was achieved in 6/12 patients (50%), while 1 patient required cervical exploration due to an ectopic adenoma. On a per-lesion basis, sensitivity, positive predictive value, and accuracy of 11 C-choline PET/CT were 100%, 88% and 88%, respectively.

Conclusions

In patients with strong clinical and biochemical suspicion of primary Hyperparathyroidism and inconclusive or discordant first-line imaging, ¹¹C-choline PET/CT provides precise localization of pathological parathyroid glands with high diagnostic accuracy, facilitating minimally invasive surgery and potentially reducing the need for bilateral cervical exploration.

ABAOCNMB173: Decoding Diagnostic Dilemmas in Renal Transplantation: The Role of 18F-FDG PET/CT in Differentiating Infection, Malignancy, and Inflammation

Jaswinder Jaswinder, Manish Ora, Prasanta Kumar Pradhan

Sanjay Gandhi Post Graduate Institute Of Medical Sciences

Purpose

Renal transplantation is curative treatment of end-stage renal disease. India’s renal transplant program is most successful in the world, second only to USA. The patient often requires lifelong variable immunosuppression, leading to severe complications that are uncommonly observed in immunocompetent individuals. Diagnostic challenges arise due to overlapping clinical features of rejection, infection, and malignancy. Adding to the complexity of clinical scenario, limited accuracy of conventional tests makes it challenging. 18F-fluorodeoxyglucose PET/CT is promising, non-invasive functional imaging technique that enables early detection and differentiation of post-transplant complications. This retrospective study evaluates role of 18-FDG PET/CT in addressing equivocal or undiagnosed diagnostic challenges in post-renal transplant patients.

Materials and Methods

A retrospective study evaluated clinical records of post-renal transplant patients from 2020 to 2022 involving 39 patients (male 33) with mean age of 46±19 (25-63). Patient presented with complaints of pyrexia of unknown origin, intractable diarrhea, vague abdominal pain, weakness and significant weight loss. Patients underwent routine biochemical investigation, microbiological investigations, and conventional imaging. Whole body FDG PET/CT imaging was performed when routine investigations identified no convincing clinically relevant cause. Image-guided histopathological, biochemical or microbiological investigations were performed based on PET/CT findings. Detailed reviews of HIS were conducted to gather clinical information and confirm final diagnosis.

Results

Patients presented with symptoms of weight loss (25), diarrhea (20), fever (6), abdominal pain (4) and others in minority with symptoms such as burning micturition and multiple subcutaneous swelling. Among the 39 recipients, 20 (~51%) scans show no metabolically abnormal non-physiological metabolic activity. Patients were managed conservatively and discharged successfully. Nine patients had abnormal focal uptake suspicious for malignancy or local inflammatory lesion. Six patients underwent HPE; two were positive for malignancy (DLBCL) and four came out negative for malignancy. The scan was suspicious for infections or inflammations in 10. Patients were evaluated, and PET/CT-guided management was done and discharged successfully.

Conclusion

In renal transplant recipients, FDG PET/CT shows unparalleled performance for complex clinical scenarios. It has excellent specificity in ruling out significant inflammation or malignant pathology, leading to conservative management and successful discharge. FDG PET/CT identifies metabolically active foci, aiding in guiding further investigations and management. It is prudent for Nuclear medicine physician to be well-versed in diverse clinical scenarios in this setting. FDG PET/CT, a whole-body functional modality without nephrotoxic contrast, is safe and effective modality in the post-renal transplant setting.

ABAOCNMB207: Assessing the performance of FAPI PET/CT in detecting primary hepatobiliary neoplasms in comparison with FDG PET/CT - Systematic review and meta-analysis.

Dr Vishnukumar R, Dr Gowri Sankar, Dr Gayane Aghakhanyan, Mr. Poovendhan M, Dr Lakshman AM

All India Institute of Medical Sciences

Introduction and Aims

Primary hepatobiliary malignancies, including hepatocellular carcinoma, cholangiocarcinoma, and gallbladder carcinoma, pose significant diagnostic challenges due to complex anatomical locations and histological variability. While FDG PET/CT is established for oncologic staging, its sensitivity for primary detection varies, especially with mucinous subtypes and low-FDG avid variants. Recently, FAPI PET/CT, targeting fibroblast activation protein, has shown promise for improved detection due to high stromal expression in these tumours. This systematic review and meta-analysis aimed to directly compare the diagnostic accuracy of FAPI PET/CT versus FDG PET/CT for primary hepatobiliary malignancies, focusing on sensitivity, specificity, and semi-quantitative imaging parameters.

Materials and Methods

Systematic searches were conducted in PubMed, Scopus, EMBASE, Web of Science, and EBSCO for studies comparing FAPI and FDG PET/CT in hepatobiliary malignancies up to March 25, 2025. Paired studies applying both index tests to the same patients were included, with tissue diagnosis or imaging follow-up used as reference standards. QUADAS-2 and QUADAS-C tools were used for risk of bias assessment. Bivariate random-effects models and meta-regression were used for pooled sensitivity and specificity estimation. Semiquantitative comparisons of SUVmax and tumour-to-background ratio (TBR) were performed. Publication bias was assessed using funnel plots and Deeks’ test.

Results

Sixteen studies, predominantly from Asia and Europe, met inclusion criteria and provided data on diagnostic accuracy and imaging parameters. For primary lesions, the pooled sensitivity of FAPI PET/CT was 0.959 (95% CI: 0.84–0.99), outperforming FDG PET/CT (0.699, 95% CI: 0.53–0.83). FDG PET/CT demonstrated higher specificity (0.865, 95% CI: 0.22–0.99) compared to FAPI PET/CT (0.587, 95% CI: 0.24–0.87), though this difference was not statistically significant. For lymph node metastases, FAPI PET/CT showed both higher pooled sensitivity (0.918 vs. 0.797) and specificity (0.73 vs. 0.59) than FDG PET/CT. Semiquantitative analyses revealed significantly higher SUVmax and TBR for FAPI PET/CT in primary and lymph node lesions, supporting superior lesion conspicuity. Heterogeneity was notable but major pooled effects remained robust. No significant publication bias was detected for primary lesion meta-analyses.

Conclusion

FAPI PET/CT surpasses FDG PET/CT in sensitivity for primary hepatobiliary tumours and demonstrates enhanced detection of lymph node metastases and superior semiquantitative imaging metrics. While specificity differences merit cautious interpretation, especially due to study heterogeneity, the findings support a complementary diagnostic role for FAPI PET/CT in clinical staging and management of hepatobiliary malignancies. Further prospective studies are mandated to refine clinical protocols and establish long-term impact on outcomes.

ABAOCNMB212: REDEFINING RESPONSE IN METASTATIC CASTRATION‑RESISTANT PROSTATE CANCER: A COMPARATIVE EVALUATION OF RECIST1.1, RECIP1.0, AND PPP CRITERIA USING 68GA-PSMA-11 PET/CT

Ramanmanojkumar Toshniwal, Kunal Ramesh Chandekar, Sulochana Sarswat, Anis Bashir Fomda, Ayan Dhiman, Aakash Aravindh Murugan, Nishikant Avinash Damle, Abhinav Singhal, Madhavi Tripathi, Chandrasekhar Bal

All India Institute of Medical Science, AIIMS New Delhi

Introduction

Conventional anatomical response criteria may not adequately capture post-treatment molecular changes in metastatic castration-resistant prostate cancer (mCRPC). This study compared RECIST1.1, RECIP1.0, and PSMA-PET progression (PPP) criteria for response evaluation using PSMA PET/CT in men with mCRPC.

Materials and Methods

We screened records of 73 mCRPC patients who underwent ⁶⁸Ga-PSMA-11 PET/CT at baseline and follow-up while on systemic therapy between 2022–2024. Patients with missing clinical, laboratory or imaging data were excluded. Pairwise kappa and cross-tabulations were used to assess inter-criteria concordance. Survival outcomes were analyzed using Kaplan-Meier curves and Cox regression.

Results

Seventy-three men (median age, 64 years [IQR, 58–71]) were included. 23 (31.5%) patients were on taxane-based chemotherapy, 9 (12.3%) on platinum-based chemotherapy, 16 (21.9%) on androgen receptor pathway inhibitors (ARPIs), and 25 (34.3%) on ¹⁷⁷Lu-PSMA-617 radioligand therapy. 35.6% patients were on first-line therapy, 32.9% on second-line and 31.5% were on third-line (and beyond) therapy for mCRPC. Biochemical response (serum PSA decline ≥50%) was observed in 18 (~25%) patients. The median follow up duration was 14 months (95% CI, 11.6-16.3). Median PFS was 9 months (95% CI, 5.9-12.1) while the median OS was 26 months (95% CI, 23.2-28.8). RECIP1.0 showed moderate concordance with RECIST1.1 (weighted kappa=0.529). PPP-criteria showed substantial to excellent concordance with both RECIST1.1 (kappa=0.753) and RECIP1.0 (kappa=0.891). Objective response by RECIP1.0 showed stronger positive correlation with biochemical response than RECIST1.1 (Spearman’s r = 0.635 vs 0.400, respectively). RECIP1.0 objective response was significantly associated with improved PFS (HR, 0.31; 95% CI, 0.16–0.59; P<0.001), whereas RECIST1.1 was not significantly associated with PFS (HR, 0.67; 95% CI, 0.27–1.70; P=0.399). PD-status by PPP criteria (HR 3.85 95% CI, 2.14-6.93; p<0.001) was also significantly associated with inferior PFS. However, none of the response criteria were significantly associated with OS.

Conclusion

PET-based RECIP1.0 and PPP-criteria demonstrated prognostic value comparable to or greater than RECIST1.1 for PFS outcomes. PSMA PET/CT may serve as a reliable, hybrid, one-stop imaging modality for response assessment in mCRPC.

ABAOCNMB198: Comparison of [⁶⁸Ga] Ga DOTA-TATE PET/CT with current standard conventional imaging (MRI) in management of meningiomas.

Rajalakshmi D, Julie Hephzibah, Saumya Sunny, Justin Benjamin, Junita Rachel John

Christian Medical College

Introduction

Meningiomas are the most common primary intracranial tumours, majority are benign (World health organisation WHO grade I), showing slow growth and low recurrence. WHO grade II (atypical) and WHO grade III (malignant) are more aggressive. MRI, current modality of choice in imaging. However, functional imaging has been gaining importance in recent times. Targeting somatostatin receptor-2 (SSTR2) expression with [⁶⁸Ga] Ga-DOTATATE PET-CT is useful for detection and treatment planning.

Aim

To compare [⁶⁸Ga] Ga-DOTATATE in correlation with current standard of conventional imaging (MRI) in management of Meningiomas.

Materials and Methods

Prospective pilot study was conducted between September 2023 – June 2025. MRI brain and [⁶⁸Ga] Ga-DOTATATE PET-CT were performed in 20 patients with indications of post excision assessment, suspected meningiomas and in unresectable meningiomas. Along with cross sectional and functional imaging findings, histopathological details were also reviewed.

Results

Total of 20 patients (M/F: 11:9, age group range: 32-76 years) were included. Imaging was performed in 17 patients for post-excision assessment and unresectable meningioma in 3 patients. HPE (done in 17 cases) – CNS WHO grade 1 (2), grade 2 (14) and grade 3 (1) with MIB index ranging from 2-20% and not available in 3 cases.

MRI was positive in 14/20 cases (9 residual, 2 recurrent and 3 primary tumours) and negative in 6. [⁶⁸Ga] Ga-DOTATATE PET-CT was positive in 16/20 cases including 10 residual lesions (1 MRI negative case), 2 recurrent lesions, 3 primary tumours and 1 inflammatory lesion (hyperostosis). [⁶⁸Ga] Ga-DOTATATE PET-CT detected all the residual, recurrent lesions evident on MRI and was negative in 4 cases.

Out of the 20 patients, 8 came for follow-up one year after completing radiation therapy, during which [⁶⁸Ga] Ga DOTATATE PET CT and MRI brain were performed to look for recurrence and treatment response. [⁶⁸Ga] Ga DOTATATE PET CT was positive in 5 cases, including one inflammatory case, and negative in 3 cases. 4/8 cases showed a reduction in SUVmax of [⁶⁸Ga] Ga DOTATATE. MRI brain was positive in 4 cases and negative in 4 cases.

Conclusion

[⁶⁸Ga] Ga-DOTATATE PET-CT is a promising PET tracer in detecting all grades of meningioma, particularly in post-op settings, when MRI can be ambiguous. [⁶⁸Ga] Ga DOTATATE uptake can also be a surrogate for SSTR expression in meningioma cases, provides excellent volume delineation for radiotherapy planning and plays a major role in the response assessment. [⁶⁸Ga] Ga DOTATATE PET CT is an excellent tool for assessing treatment responses, especially post radiation therapy by measuring maximum standardized uptake values (SUVmax), offering valuable insights even when anatomical lesions appear stable on conventional imaging. Additionally, the expression of SSTR2 opens opportunities for a unique approach that combines diagnosis and therapy, known as “Theragnostic.”

ABAOCNMB185: Role of F-18 FDG PET/CT in evaluation of Hypertrophic Pachymeningitis

Aakasharavindh Murugan, Madhavi Tripathi, Jasmine Parihar, Ajay Garg, Nishikant Damle, C.S Bal, Chakshine S, Raman Toshniwal, Saurabh Singh

ALL INDIA INSTITITUE OF MEDICAL SCIENCES

Introduction

Hypertrophic pachymeningitis is a rare inflammatory disorder characterized by abnormal thickening of the dura mater. It may be idiopathic (primary) or secondary to infections, autoimmune diseases or neoplasia. Clinical manifestations are diverse and often nonspecific, including headache, seizures, cranial nerve palsies and myelopathy. MRI is the gold standard for detecting dural thickening; however, distinguishing idiopathic from secondary causes remains challenging. In some patients, a definitive diagnosis requires meningeal biopsy—a procedure associated with considerable morbidity. While not routinely employed, FDG PET/CT may provide an important non-invasive alternative by identifying metabolically active lesions and highlighting systemic involvement. Its established role in conditions such as tumors, tuberculosis, sarcoidosis, and IgG4-related disease—all recognized causes of secondary pachymeningitis —suggests that FDG PET/CT could help uncover etiology and, in select cases obviate the need for meningeal biopsy.

Aim

To evaluate the proportion of hypertrophic pachymeningitis cases in which FDG PET-CT aids in establishing an etiologic diagnosis.

Materials and Methods

This prospective study included patients presenting with pachymeningeal thickening on MRI without a definitive etiological diagnosis. All patients underwent whole-body FDG PET/CT acquired 45–60 minutes post-injection and were evaluated for areas with abnormal radiotracer uptake. Etiology was determined through characteristic uptake patterns or by identifying a hypermetabolic extracranial (systemic) site suitable for biopsy. Following confirmation of diagnosis, patients received appropriate treatment for the underlying condition and followed up to assess for clinical improvement.

Results

Nineteen patients in total with hypertrophic pachymeningitis underwent FDG-PET/CT. The scan identified the etiology in one patient and suggested extra-cranial biopsy sites in three others, guiding diagnosis in 4/19 patients (21%).

Of 19 patients, only 2 consented to meningeal biopsy. Both had non-diagnostic PET/CT findings, and biopsy results were also non-contributory.

Fifteen patients with non-diagnostic PET/CT were classified as having idiopathic hypertrophic pachymeningitis and managed conservatively.

The 4 patients with an established etiology received appropriate treatment and demonstrated symptomatic improvement on follow-up, indirectly confirming the diagnosis.

Conclusion

FDG-PET/CT is a useful tool in the etiological diagnosis of hypertrophic pachymeningitis, as it is a very sensitive modality and can be used to rule out systemic disease involvement. A negative FDG-PET/CT should prompt clinicians to consider idiopathic hypertrophic pachymeningitis as the likely diagnosis and to reserve invasive procedures such as meningeal biopsy for cases with strong clinical indications.

ABAOCNMB213: Correlation of Metabolic Parameters of FDG PET CT with Histopathological Parameters in Treatment-Naive Cases of Renal Cell Carcinoma (RCC).

Vishnukumar Selvaraj, Shreya Datta Gupta, Madhur Kumar Srivastava

NIZAM’S INSTITUTE OF MEDICAL SCIENCES (NIMS)

Introduction

Renal cell carcinoma (RCC) shows diverse metabolic and histopathological characteristics influencing prognosis. This study evaluates the correlation between metabolic parameters derived from 2-[¹⁸F]Fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) like SUV (Standardised Uptake Value), MTV (Metabolic Tumor volume), and TLG (Total Lesion Glycolysis) with histopathological features such as grade, necrosis, Histological tumor volume (HTV) in treatment-naive RCC cases to assess their potential role as non-invasive indicators of tumor aggressiveness.

Materials and Methods

This retrospective study included 38 treatment-naive with histopathologically proven RCC patients who underwent 18F-FDG PET/CT. Scans were performed using a standard acquisition protocol & metabolic parameters were calculated using the inbuilt software of the GE Advanced Workstation 4.7 at an absolute SUV threshold of 2.5 and a relative threshold of 40%. These were correlated with histopathological features including grade, necrosis, and HTV. Correlation analysis was performed using Pearson or Spearman tests as appropriate, with p < 0.05 considered statistically significant.

Results

A total of 38 treatment-naive RCC patients (30 males – 78.9% & 8 females – 21.0%; mean age 53.3 years) were analyzed. Of these, 23 underwent surgery and 15 had FNAC/biopsy from the kidney or metastatic site. HTV (cm³), calculated as 0.523 × L × W × H, showed strong correlation with MTV and TLG (r = 0.66 & 0.63, p < 0.05), while SUV values showed moderate to weak correlation. Also, non clear-cell variants showed higher metabolic values than clear cell RCC. In clear cell RCC ISUP 3-4 grades showed higher metabolic parameters than lower ISUP grades. Tumors with histologically proven necrosis, venous thrombosis & metastases had higher metabolic parameters when compared to normal counterparts, eg., tumors with histological necrosis had significantly higher mean TLG (142.6 ± 68.4) and SUVmax (8.9 ± 3.1) compared with non-necrotic lesions (p < 0.01) and TLG demonstrated the strongest correlation followed by SUVmax. Also, the SUVmax of hottest metastatic lesion shows strong correlation with SUV values of primary lesion (r = 0.9, p < 0.05).

Conclusion

Beyond its routine role in detecting metastases, PET-derived metabolic parameters correlated well with histological features offering valuable insights into tumour biology. TLG shows a strong association with HTV, markers of aggressiveness and should be considered alongside or even beyond SUVmax in initial evaluation, aiding risk stratification, subtype identification, and management planning in treatment-naive RCC.

ABAOCNMB206: Revealing the Hidden Lymphoma: Diagnostic and Therapeutic Impact of 18F-FDG PET/CT in an Atypically Presented Follicular Lymphoma

Mohit Seth, Partha S Choudhury, Manoj Gupta, Atul Pathak, Ankur Pruthi, Mansha Vohra

RAJIV GANDHI CANCER INSTITUTE AND RESEARCH CENTRE

Introduction and Aims

Follicular lymphoma, a typically indolent B-cell non-Hodgkin lymphoma, commonly manifests with generalised lymphadenopathy or bone marrow infiltration. However, atypical initial presentations may mimic primary thoracic malignancies, creating diagnostic uncertainty. This case highlights the transformative role of 18F-FDG PET/CT in unmasking an unsuspected systemic lymphoproliferative disorder that initially mimicked a mediastinal mass, and demonstrates how functional imaging refined staging, guided biopsy, and influenced subsequent therapeutic decisions.

Materials and Methods

A 73-year-old male presented with progressive dysphagia and retrosternal discomfort. Contrast-enhanced CT of the chest revealed a heterogeneously enhancing subcarinal mass abutting the oesophagus, raising the differential of oesophageal or mediastinal carcinoma. To characterise its metabolic nature and delineate disease extent, a whole-body 18F-FDG PET/CT was performed according to EANM guidelines. Semi-quantitative parameters including SUVmax, metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were assessed.

Results

PET/CT demonstrated intensely FDG-avid lymph nodes in the mediastinum, bilateral cervical, axillary, abdominal, and pelvic stations (SUVmax ≈ 14), without evidence of a primary mucosal or visceral lesion. The distribution pattern favoured a lymphoproliferative disorder rather than carcinoma. EBUS-guided biopsy from the subcarinal node confirmed follicular lymphoma (Grade 1–2). The disease was upstaged to Stage III according to Lugano classification. Following R-CHOP immunochemotherapy, interim PET/CT revealed marked metabolic regression (Deauville score 2), validating early therapeutic response and confirming the metabolic precision of PET-based monitoring.

Conclusion

This case underlines the indispensable value of 18F-FDG PET/CT in redefining atypical oncologic presentations. By uncovering the systemic nature of disease initially presumed localised, PET/CT not only prevented potential misdiagnosis but also directed appropriate biopsy and optimised therapeutic strategy. Beyond visual assessment, incorporation of quantitative PET metrics strengthened objective evaluation of treatment response. The case reaffirms PET/CT’s evolving role as the functional compass of precision oncology — guiding clinicians from uncertainty to clarity, and from localisation to personalisation in lymphoma management.

ABAOCNMB238: Outperforming FDG? Evaluating the Diagnostic Superiority of ⁶⁸Ga-FAPI-46 PET/CT in Breast Cancer Staging

SHIBIRAJ PATEL, SHIBIRAJ PATEL, SHANMUGA SUNDARAM P.

Gujarat Imaging Centre

Aim/Introduction

To compare the diagnostic performance of ⁶⁸Ga-FAPI-46 PET/CT and ¹⁸F-FDG PET/CT in the initial staging of breast cancer; to assess metabolic parameters (SUV, TBR & MTV) of primary and metastatic lesions; and to evaluate their correlation with histopathological and IHC markers (ER, PR, HER2, Ki-67).

Materials and Methods

A diagnostic cohort study was conducted from 2022-25.

Inclusion Criteria

84 FNAC-confirmed breast cancer cases undergoing initial ¹⁸F-FDG PET/CT.

Exclusion Criteria

History of prior/synchronous malignancy, treatment, pregnancy, or unwillingness to complete both scans.

Imaging Protocol

Day 1: 0.1 mCi/kg of ¹⁸F-FDG, and scanned after 60 minutes on a 16-slice PET/CT with contrast.

Day 2: Patients were injected with 2-3 mCi of ⁶⁸Ga-FAPI and scanned 30 minutes post-injection.

Results

FAPI PET/CT showed superior tumor delineation in 74 of 83 patients, detecting 5 retroareolar and 12 multifocal lesions missed by FDG. Quantitatively, FAPI showed significantly higher SUVmax (12.8 ± 5.2 vs 8.2 ± 4.0; p < 0.001), TBR (10.2 ± 3.1 vs 7.8 ± 3.6; p < 0.001), and larger MTV. Sensitivity (82/83; 98.8% vs 78/83; 95.2%), NPV (98.8% vs 80/83; 96.4%), and accuracy (81/83; 97.6% vs 80/83; 96.4%) were higher for FAPI, while specificity remained identical. Histologically, invasive lobular carcinoma showed SUVmax of 11.6 (FAPI) vs 3.8 (FDG), and invasive ductal carcinoma: 14.2 vs 9.5. FAPI showed superior uptake across all IHC subtypes except TNBC and high-grade Luminal B, where FDG was better in 9 cases. FAPI had no significant correlation with Ki-67 or grade, unlike FDG. FAPI detected 11 satellite nodules and demonstrated superior axillary node assessment (381 vs 287 nodes), with higher SUVmax (11.4 vs 8.1) and greater sensitivity (90.4% vs 83.6%) and accuracy (94.1% vs 84.8%). For internal mammary nodes, FAPI outperformed FDG in sensitivity (94.7% vs 77.3%) and accuracy (94.0% vs 78.0%). Distant metastasis detection was markedly improved with FAPI in skeletal (398 vs 286), hepatic (48 vs 38), pleural, muscular, and pulmonary lesions, all showing higher SUVmax values.

Conclusion

⁶⁸Ga-FAPI PET/CT demonstrated superior diagnostic performance over ¹⁸F-FDG PET/CT in staging breast cancer, with better lesion conspicuity, higher uptake metrics, and improved detection across various sites, particularly in low-FDG-avid subtypes.

ABAOCNMB250: Correlation of 18F FDG PET/CT Features with Histopathology in Lung Squamous Cell Carcinoma and Adenocarcinoma

Dr Rinkal Shah, *Dr Manishi L Narayan*, Dr Ajith S K, Dr Chandrakanth Puranicmath, Dr Vishal Jain, Dr Deeksha Chaudhary, Dr Subin S, Dr Vivek K Saini

Dr Manishi L Narayan, Dept of Nuclear medicine, AIIMS Rishikesh, All India Institute of Medical Sciences, Rishikesh

Introduction, Aims

Lung cancer remains the leading cause of cancer-related mortality worldwide. Distinguishing between adenocarcinoma and squamous cell carcinoma is clinically & therapeutically crucial. 18F FDG PET/CT allows quantitative evaluation of tumour metabolism through parameters such as SUVmax, SUVmean, SUVpeak, MTV & TLG. These indices may act as surrogate biomarkers of tumour aggressiveness and differentiation. This study aimed to evaluate whether these quantitative metrics can distinguish adenocarcinoma and squamous cell carcinoma of the lung.

Materials and Methods

A retrospective analysis was conducted on nineteen biopsy-proven cases of carcinoma lung who underwent 18F FDG PET/CT between July to October 2025. The cohort included 13 males (68%) and 6 females (32%) with a mean age of 61.5 ± 7.7 years (range 48–74). Histopathology confirmed 11 adenocarcinomas (58%) and 8 squamous cell carcinomas (42%). Quantitative indices including SUVmax, SUVmean, SUVpeak, MTV & TLG were obtained using semi-automated volumetric analysis. Normality testing employed the Shapiro–Wilk method. Intergroup comparisons used the Welch t-test or Mann–Whitney U test as appropriate. A logistic regression model combining MTV & TLG was constructed, and discriminatory performance was assessed by the area under the receiver operating characteristic curve.

Results

SUV peak was significantly higher in squamous cell carcinoma (11.89 ± 4.2) compared to adenocarcinoma (8.11 ± 3.9) (p = 0.049). SUVmax and SUVmean showed borderline higher values in squamous cell carcinoma (14.70 ± 5.3 vs 10.21 ± 4.7, p = 0.056; 8.13 ± 2.9 vs 5.86 ± 2.7, p = 0.071). MTV and TLG were greater in squamous cell carcinoma but not statistically significant (66.3 ± 28.1 vs 49.1 ± 25.4 mL, p = 0.15; 539.5 ± 178.2 vs 339.4 ± 120.7, p = 0.11). MTV + TLG combined logistic regression model achieved an AUC of 0.727, indicating moderate discrimination.

Conclusion

Squamous cell carcinoma demonstrated higher metabolic activity on 18F-FDG PET/CT, with significantly elevated SUVpeak & SUVmax uptake values compared to adenocarcinoma. Combined MTV + TLG modestly improved histologic differentiation. These findings suggest that quantitative PET/CT metrics may serve as potential non-invasive imaging biomarkers for histologic characterisation in carcinoma lung. Larger multicentre prospective studies are warranted for validation.

ABAOCNMB254: Brain perfusion imaging with technetium-99m ethyl cysteinate dimer in Moyamoya disease: baseline positivity and early post-revascularisation change.

Nishant Kispotta, Madhur Srivastava

NIZAM INSTITUTE OF MEDICAL SCIENCE

Introduction

Moyamoya disease (MMD) is characterised by progressive steno-occlusion of the intracranial internal carotid and middle cerebral arteries with collateral formation, predisposing to ischaemia. Brain perfusion single photon emission computed tomography (SPECT) using technetium-99m ethyl cysteinate dimer (99mTc-ECD) can depict haemodynamic compromise and early changes after revascularisation. We aimed to (i) estimate baseline 99mTc-ECD SPECT positivity in suspected or confirmed MMD and (ii) evaluate early post-operative change, with basic statistical analysis.

Materials and Methods

We performed a single-centre retrospective cohort study (calendar years 2023–2025). Demography, clinical diagnosis, angiography text reports, surgical technique, and SPECT findings were abstracted from the record. Outcomes were the proportion of positive studies at baseline (pre-operative) and early post-operative time-points, each with exact 95% confidence intervals (CI). In patients with paired pre- and post-operative studies, change was tested using McNemar’s exact test. Exploratory analyses evaluated associations between baseline positivity and sex (Fisher’s exact test) and age (Mann–Whitney U). Surgical techniques included encephalo-duro-myo-arterio-synangiosis (EDMAS) and superficial temporal artery to middle cerebral artery (STA–MCA) bypass. No imaging illustrations are included.

Results

Twenty-two patients met inclusion criteria (median age 20 years, range 2–48; 13 females). Clinical diagnosis distribution was: bilateral MMD 9/23; unilateral right 4/23; unilateral left 2/23; and unspecified or possible MMD 7/23. Pre-operative SPECT was available in 18/23 and was positive in 9/18 (50%; exact 95% CI 26–74%). First revascularisation was performed in a majority, most commonly EDMAS, with STA–MCA bypass used in a minority. Early post-operative SPECT was available in 10/23 and was positive in 1/10 (10%; exact 95% CI 0.3–44.5%). Among patients with paired studies (n=5), 3/5 converted from positive to negative and 0/5 converted from negative to positive (McNemar two-sided p=0.25), indicating a favourable direction of change though underpowered. Exploratory analyses showed no significant association between baseline positivity and sex (Fisher p=0.153) or age (Mann–Whitney p=0.77).

Conclusion

In this single-centre cohort, half of pre-operative 99mTc-ECD SPECT studies demonstrated perfusion abnormality, while early post-operative scans were infrequently positive, with paired analysis suggesting improvement after revascularisation. These data support the role of 99mTc-ECD SPECT for baseline assessment and early follow-up in Moyamoya disease. Future work should standardise angiographic grading, incorporate quantitative perfusion metrics, and increase paired sampling to enable adequately powered hypothesis testing and time-to-scan analyses.

ABAOCNMB263: RADIOMIC HABITAT-BASED SEMI-AUTOMATIC SEGMENTATION OF PET LESIONS: ADDRESSING LIMITATIONS OF FIXED SUV THRESHOLDS IN LOW-UPTAKE TUMORS

Poovendhan Mathiyazhagan, Madhusudhanan Ponnusamy

Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER)

Introduction and Aims

Current Positron Emission Tomography (PET) lesion segmentation is typically done manually or using SUV thresholds (42% SUV or fixed SUV - 2.5), semi-automatic and automatic methods. Manual segmentations are not reproducible making standardisation difficult, thus automatic or semi-automatic methods have to be used, Though automatic segmentation using deep learning networks in PET is promising, it is resource intensive and requires large volume of labelled data for its training. In contrast, Semi-automatic methods are faster, less resource intensive and are based on mathematical models and ensure repeatability. These approaches demonstrate significant limitations in low-uptake tumors and heterogeneous lesions where tumor boundaries are poorly defined by intensity alone. We developed a novel radiomic habitat-based semi-automatic segmentation method leveraging voxel-level texture patterns to accurately delineate tumor boundaries, particularly in challenging low-uptake lesions where conventional methods fail.

Methods

We developed a semi-automatic segmentation plugin written in python as a module for 3D Slicer (Version 5.8.1) implementing radiomic habitat analysis. The method was evaluated in primary breast cancer patients with both low-uptake and high-uptake lesions.

The segmentation process comprised:

1. Lesion selection with bounding box placement

2. Voxel-wise radiomic feature extraction using a sliding window of 3 voxels

3. Generation of radiomic feature maps

4. K-means clustering to generate radiomic habitats

5. Automatic selection of the most tumor-representative habitat

6. Morphological refinement to smooth boundaries.

Segmentation volumes were compared against 42% SUVmax and fixed SUV 2.5 thresholds, with validation against CT-defined true tumor volumes.

Results

In low-uptake tumors, the radiomic habitat method successfully segmented lesions compared to CT structure where conventional methods failed or produced irregular volumes. In high-uptake tumors, performance was comparable to conventional methods while demonstrating better handling of heterogeneous lesions due to the morphological refinement process included in the plugin. Processing time ranged from 30 seconds to 2 minutes per lesion. A multi-lesion detection approach was also explored, where users segment one reference lesion, extract its radiomic signature, and the plugin automatically identifies similar lesions across the entire body based on feature similarity.

Conclusion

Radiomic habitat-based segmentation represents a significant advancement over fixed SUV threshold methods, particularly for low-uptake tumors. The voxel-level texture analysis captures tumor heterogeneity patterns defining true biological boundaries beyond simple intensity thresholds. This approach can help in the standardization of radiomic feature extraction, addressing critical unmet needs where existing guidelines provide inadequate guidance and even help in the identification of similar lesions using similar radiomic signature.

ABAOCNMB240: Impact of Renal Depth Estimation and Attenuation Correction techniques on Glomerular Filtration Rate Measurement by Renal Scintigraphy in patients with Renal Mass Lesions

Krishna Kamal, Abubacker Zakir Ali

Basavatarakam IndoAmerican cancer Hospital

Introduction and Aim

Tumour size is a key determinant in renal cell carcinoma (RCC) staging and surgical management. Partial nephrectomy is recommended for most T1a tumours (<4 cm) and considered for selected T1b tumours (4–7 cm) to preserve renal function without compromising oncologic outcomes. Radical nephrectomy is generally preferred for tumours >7 cm, although nephron-sparing surgery is considered in conditions such as solitary kidney or baseline renal impairment.

Accurate preoperative assessment of glomerular filtration rate (GFR) is therefore critical, particularly when nephron-sparing surgery is planned. 99mTc-DTPA renal scintigraphy using the Gates method is widely employed for assessing split renal function. However, its accuracy is influenced by attenuation and renal-depth correction especially in conditions such as renal mass lesions where normal anatomic relationships may be altered.

CT-based depth measurement provides individualized depth assessment, whereas the Tonnesen formula is anthropometric. The geometric-mean method provides attenuation correction through anterior–posterior counts without explicit depth estimation. This study aims to evaluate the effect of renal depth estimation methods and geometric mean attenuation correction on GFR measurement using 99mTc-DTPA renal scintigraphy in patients with renal mass lesions.

Methods

Sixty-seven patients with renal mass lesions who underwent 99mTc-DTPA renal scintigraphy between January 2024 and September 2025 were included. Renal depth was obtained using CT-based measurement (from prior diagnostic scans or low-dose CT) and the Tonnesen formula and attenuation correction was performed using the geometric-mean method. Split renal GFR was calculated using the Gates method and eGFR (CKD-EPI) was used as the reference. Patients were stratified by mass size: <4 cm (n=11), 4–7 cm (n=17), and >7 cm (n=39). GFR values were compared with eGFR using a paired-sample t-test. A P-value <0.05 was considered statistically significant.

Results

For tumours <4 cm, no statistically significant differences were observed between GFR values from CT-based depth, geometric-mean correction, or Tonnesen calculations versus eGFR (P>0.05).

And for tumours 4–7 cm and >7 cm, CT-based and geometric-mean corrected values demonstrated no significant difference from eGFR (P>0.05), but the GFR values derived using the Tonnesen method differed significantly across both groups (P<0.05).

Conclusion

CT-based depth estimation and geometric-mean attenuation correction based GFR values closely aligned with eGFR and appear comparable across all tumour size groups. The Tonnesen method demonstrated significant deviation in patients with larger tumours, limiting its reliability in these patients. Further statistical and correlation analyses are ongoing and will be presented in the final report.

ABAOCNMB264: Differentiating non small cell Lung Cancer Subtypes Using 18F-FDG PET/CT: A Histopathological Correlation Study

Rinkal Shah, Manishi L Narayan*, Ajith S K, Dr Chandrakanth Puranicmath, Vishal Jain, Deeksha Chaudhary, Subin S, Vivek K Saini

*Coresponding author : Dr Manishi L Narayan, Dept of Nuclear medicine, AIIMS Rishikesh

Introduction, Aims

Lung cancer remains the leading cause of cancer-related mortality worldwide. Distinguishing between adenocarcinoma and squamous cell carcinoma is clinically & therapeutically crucial. 18F FDG PET/CT allows quantitative evaluation of tumour metabolism through parameters such as SUVmax, SUVmean, SUVpeak, MTV & TLG. These indices may act as surrogate biomarkers of tumour aggressiveness and differentiation. This study aimed to evaluate whether these quantitative metrics can distinguish adenocarcinoma and squamous cell carcinoma of the lung.

Materials and Methods

A retrospective analysis was conducted on nineteen biopsy-proven cases of carcinoma lung who underwent 18F FDG PET/CT between July to October 2025. The cohort included 13 males (68%) and 6 females (32%) with a mean age of 61.5 ± 7.7 years (range 48–74). Histopathology confirmed 11 adenocarcinomas (58%) and 8 squamous cell carcinomas (42%). Quantitative indices including SUVmax, SUVmean, SUVpeak, MTV & TLG were obtained using semi-automated volumetric analysis. Normality testing employed the Shapiro–Wilk method. Intergroup comparisons used the Welch t-test or Mann–Whitney U test as appropriate. A logistic regression model combining MTV & TLG was constructed, and discriminatory performance was assessed by the area under the receiver operating characteristic curve.

Results

SUV peak was significantly higher in squamous cell carcinoma (11.89 ± 4.2) compared to adenocarcinoma (8.11 ± 3.9) (p = 0.049). SUVmax and SUVmean showed borderline higher values in squamous cell carcinoma (14.70 ± 5.3 vs 10.21 ± 4.7, p = 0.056; 8.13 ± 2.9 vs 5.86 ± 2.7, p = 0.071). MTV and TLG were greater in squamous cell carcinoma but not statistically significant (66.3 ± 28.1 vs 49.1 ± 25.4 mL, p = 0.15; 539.5 ± 178.2 vs 339.4 ± 120.7, p = 0.11). MTV + TLG combined logistic regression model achieved an AUC of 0.727, indicating moderate discrimination.

Conclusion

Squamous cell carcinoma demonstrated higher metabolic activity on 18F-FDG PET/CT, with significantly elevated SUVpeak & SUVmax uptake values compared to adenocarcinoma. Combined MTV + TLG modestly improved histologic differentiation. These findings suggest that quantitative PET/CT metrics may serve as potential non-invasive imaging biomarkers for histologic characterisation in carcinoma lung. Larger multicentre prospective studies are warranted for validation.

ABAOCNMB237: Benign but Not Simple: Spectrum of Rare and Challenging Thyroid Disorders in a High-Volume Thyroid Clinic

Yogita Khandelwal, Nishikant A Damle, Bela Jain, Cs Bal, Vishnu Ar, Nikhil Tandon, Manaswani Bhatt

AIIMS, New Delhi

Introduction

Benign thyroid diseases are common, but a small subset may present with rare and atypical manifestations that may pose significant diagnostic dilemma or lead to severe complications. From our thyroid clinic database of over 9,000 patients, we are presenting a spectrum of unique 19 benign thyroid disease patients having diagnostic dilemmas or challenges

Material and Methods

A retrospective review was conducted of thyroid clinic records from 2000 to 2025. Inclusion criteria: (i) histologically or clinically proven benign thyroid disease, (ii) unusual presentation or diagnostic confusion with malignancy, and (iii) complete data with follow-up. Clinical, biochemical, imaging (USG, scintigraphy, SSTR-PET/CT where available), cytology/histopathology, treatment, and outcomes were analyzed.

Results

Nineteen patients (13 females, 6 males; age 5–73 years) were included. Spectrum comprised: autonomously functioning thyroid nodule in McCune–Albright syndrome (n=1), ectopic mediastinal thyroid with SSTR expression (n=2), thyroid storm (n=5; following RAI, non-compliance, insufficient ATD, with deranged liver function, with Budd–Chiari syndrome), Riedel’s thyroiditis (n=1), triple ectopic thyroid (n=1), Marine–Lenhart syndrome (n=1), thyroid hemiagenesis (n=1), Graves’ disease with neuropsychiatric conditions (Down’s syndrome n=2, cerebral palsy n=1, schizophrenia n=1), amiodarone-induced thyroiditis (n=1), and thyroid tuberculosis (n=2). Diagnostic overlap with carcinoma was notable in Riedel’s thyroiditis, ectopic mediastinal thyroid, and thyroid tuberculosis, while others were challenging to manage.

Conclusion

Rare benign thyroid conditions like the above can pose a diagnostic challenge or present with life-threatening crises such as thyroid storm. Multimodality evaluation remains critical to avoid misdiagnosis and unnecessary aggressive therapy. Awareness of such presentations among clinicians is crucial for accurate diagnosis, optimal treatment, and better patient outcomes.

ABAOCNMB178: When More is Not Better: Limited Impact of Higher Radioiodine Dose in remnant ablation in differentiated thyroid cancer with elevated serum thyroglobulin Thyroid cancer, remnant ablation, Radioiodine therapy, serum thyroglobulin

Manish Ora, Aftab Hasan Nazar, Amitabh Arya, Sukanta Barai, Prasanta Kumar Pradhan

SGPGIMS

Background

Radioiodine (RAI) ablation is a standard therapeutic approach in intermediate to high-risk well-differentiated thyroid cancer (DTC). This study aimed to evaluate the prognostic value of the clinical profile, Histopathology, pre-ablation stimulated thyroglobulin (Tg) levels, and administered RAI activity on ablation success in DTC.

Methods

A retrospective analysis was conducted on 250 patients who underwent RAI ablation following total thyroidectomy. Tg level of 10.5 ng/mL was determined as a cutoff for predicting remnant success in this cohort, which concides with our previous publication (12.6 ng/mL). Patients were stratified based on Tg levels into two groups: Tg < 10.5 ng/mL (n = 138) and Tg ≥ 10.5 ng/mL (n = 112). They were further categorized according to the administered RAI activity: <1.85 GBq (n = 122) and ≥1.85 GBq (n = 128). Ablation outcomes were classified as successful or failed, determined by biochemical remission (undetectable Tg and negative anti-Tg antibody) and confirmatory diagnostic whole-body imaging at 6 months after ablation.

Results

Ablation success was achieved in 164 (65.5%) patients. Among the Tg <10.5 ng/mL, ablation success was observed in 116 patients (84.1%), compared to only 24 (21.2%) in the Tg ≥10.5 ng/mL group (p < 0.01). Within the low-Tg cohort, ablation success was similar regardless of RAI activity: 62 (81.6%) with <1.85 GBq versus 54 (86.6%) with ≥1.85 GBq (p>0.05). Conversely, in patients with Tg ≥10.5 ng/mL, ablation success was noted in 20/65 patients (30.8%) with <1.85 GBq and 4/47 patients (8.5%) with ≥1.85 GBq, resulting in an overall failure rate of 78.8%. Age, sex, stage, and surgical extent were not predictors of ablation.

Conclusion

Pre-ablation stimulated Tg levels represent a robust and independent predictor of ablation success in DTC. Patients with low Tg (<10.5 ng/mL) demonstrate excellent outcomes, and higher RAI doses do not provide additional benefit in this subgroup. In contrast, elevated Tg exhibits poor outcomes, despite higher RAI activity. This study recommend a lower (<50 mCi) targeted RAI dose in favorable cases, while avoiding futile dose escalation in high-risk patients with elevated Tg levels (>10.5 ng/mL).

ABAOCNMB261: CLINICAL SIGNIFICANCE OF THYROID INCIDENTALOMAS DETECTED ON 18-F FDG PET/CT SCAN

Arya Nair Sreekala, Teena Sleeba, Neshwa Noushad, Naveen Jose Moolan, Vijay Harish Somasundaram

Rajagiri Hospital

Introduction

With the advent of advanced imaging modalities like PET/CT, thyroid incidentalomas are now increasingly being detected. Many of these incidentalomas represent benign lesions but the main challenge remains differentiating clinically significant malignant lesions from asymptomatic benign ones to guide appropriate management and avoid unnecessary interventions. Thyroid incidentalomas detected on 18F-FDG PET show a higher malignancy risk (20–50%) than other imaging modalities like CT, ultrasound or MRI. Most publications on PET incidentalomas are from Western population studies with limited number of studies in the Indian scenario. This study analyzes their prevalence and characteristics in the Indian population, as there is a striking regional difference in thyroid cancer prevalence in these populations.

Aims

• To investigate the clinical significance of incidental focal or diffuse FDG uptake in the thyroid gland on PET/CT and to evaluate the prevalence of malignancy potential of thyroid incidentalomas.

• To explore the relation of TFT with diffuse uptake on PET-CT

• To find any correlation between CT attenuation (HU) and thyroid nodule character

• To compare standardized uptake values (SUV max) in thyroid malignancy of our study population and results from other studies

Materials and Methods

Study includes all patients undergoing FDG PET for non-thyroid illness from April 2021 April to 2023 December in Department of Nuclear Medicine, Rajagiri hospital.

All patients with focal thyroid uptake willing for further evaluation underwent a neck ultrasound. USG guided-FNAC of focal nodules was performed in willing patients, using a core 23G needle. TSH level was measured with the chemiluminescence technique. Data was analysed using relevant statistical methods.

Conclusion

We analyzed 335 patients with abnormal thyroid uptake out of 2574 18F-FDG PET/CT scans performed for non-thyroid illnesses. The prevalence of PET-detected thyroid incidentalomas (PET-omas) was 4.5%, slightly higher than previous reports. Sixty percent of focal incidentalomas were malignant, predominantly papillary carcinoma. Diffuse uptake correlated strongly with hypothyroidism, consistent with chronic thyroiditis. CT attenuation showed no significant association with histology. High SUVMAX values (≥16) are almost exclusively associated with follicular neoplasm, SUVMAX (5-16) shows a trend towards papillary thyroid carcinoma, while low values (<5) were mostly benign. ROC analysis (AUC = 0.8; cutoff = 4.5) demonstrated SUVMAX as a useful discriminator of malignant thyroid incidentalomas.

ABAOCNMB157: Utility of FDG PET/CT for Disease Localization in Differentiated Thyroid Cancer Patients with Discordant Anti-Thyroglobulin Antibody and Radioiodine Scan Findings

Smrutismaraki Dash, Manish Ora, Aftab Hasan Nazar, Prasanta Kumar Pradhan

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow

Introduction

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy. Despite its high prevalence, prognosis is excellent. Based on pretreatment staging, standard treatment involves thyroidectomy, followed by assessment using whole-body radioiodine scans (WBRI), Thyroglobulin (Tg), and anti-thyroglobulin antibody (TgAb) assays. High-dose radioiodine is prescribed in intermediate-high risk patients. Tg is a sensitive tumor marker but becomes unreliable in the presence of TgAb, detected in nearly 20% of DTC patients, often associated with Hashimoto’s thyroiditis. Persistently rising TgAb suggests recurrence. This retrospective study evaluates utility of 18F FDG PET/CT in patients with persistently elevated or rising TgAb after ablation.

Materials and Methods

This retrospective study included 30 patients (mean age: 43.23 ± 14.64 years; 15- 71 years). These patients underwent high-dose radioiodine therapy. Follow-up WBRI was negative, with significantly elevated ATg levels (>100 IU/mL; normal <20 IU/mL). These patients underwent FDG PET/CT. Patients were classified based on PET/CT findings as having no active disease, operative bed recurrence, cervical lymph node (LN) involvement, mediastinal LN involvement, or systemic metastases. Non-FDG-avid multiple, well-defined, randomly distributed lung nodules in the absence of other features suggestive of infection were considered metastatic based on CT features.

Results

The median Tg was 0.2 (Q1, Q3; 0.04, 0.9 ng/dL). ATg was significantly raised (median 870.25 (213, 3867). FDG PET/CT was positive in 25 (83.3%) patients. Five (16.7%) patients showed no evidence of active disease on FDG PET/CT. Six (20%) patients had operative bed recurrence (SUVmax 4.2±2.8). 23 (76.7%) patients had FDG-avid cervical LNs (SUVmax 5.3±3.1) and 4 (13.3%) had metastatic mediastinal LNs (SUVmax 4.0±1.4). Metabolically inactive and inactive lung metastases were noted in 10 (33.3%) and 3 (10%) patients. Other metastatic sites included left axillary LN, right parapharyngeal LN, liver, and peritoneal deposits in one patient each.

Conclusion

FDG PET/CT is highly valuable in differentiated thyroid cancer patients with elevated anti-thyroglobulin antibodies and negative radioiodine scans. The most common sites of involvement were cervical lymph nodes, followed by operative bed recurrence, mediastinal nodes, and systemic metastases. CT features were very useful in characterizing non-FDG-avid pulmonary nodules as metastatic in a significant number of patients. These findings underscore the pivotal role of FDG PET/CT in this challenging subgroup, facilitating appropriate risk stratification and informing further management.

ABAOCNMB253: Analysis of Weight-Adjusted Levothyroxine Dose Requirements Stratified by TSH Targets and Age in Indian Patients with Differentiated Thyroid Carcinoma

SRIJANI MANDAL, GIRISH PARIDA, RALPH EMERSON, KANHAIYALAL AGRAWAL, SAI SRADHA PATRO, T. KISHAN SUBUDHI

AIIMS Bhubaneswar

Background

Individualized levothyroxine (LT4) dosing after thyroidectomy is essential for optimizing outcomes in differentiated thyroid carcinoma (DTC). While international guidelines recommend replacement and suppression doses of 1.6 µg/kg and 2.1 µg/kg, respectively, Indian patients often require different dose adjustments due to ethnic, metabolic, and pharmacogenetic factors.

Objective

To determine the mean LT4 dose per kilogram of body weight across different thyroid-stimulating hormone (TSH) strata and to evaluate the influence of age on dose requirements in Indian patients with DTC.

Methods

This retrospective analysis included 265 thyroidectomized patients on stable LT4 therapy with documented TSH levels and body weights. LT4 dose per kg was computed and patients stratified into TSH categories: < 0.1 mIU/L (complete suppression), 0.1–0.5 mIU/L (partial suppression), 0.5–2 mIU/L (replacement range).

Group comparisons performed using Kruskal–Wallis analysis followed by pairwise Mann–Whitney U tests (Holm correction). Cliff’s delta was used to quantify effect sizes. Age-wise stratification (<30, 30–44, 45–59, ≥60 years) was also evaluated.

Results

The mean LT4 dose per kg was: < 0.1 mIU/L: 2.39 ± 0.57 µg/kg (n = 145), 0.1–0.5 mIU/L: 2.28 ± 0.42 µg/kg (n = 65), 0.5–2 mIU/L: 2.22 ± 0.45 µg/kg (n = 35). Although a descending trend in dose observed with relaxed TSH targets, Kruskal–Wallis H = 2.09, p = 0.35 indicated no statistically significant difference among the three groups. Pairwise Mann–Whitney comparisons confirmed the absence of significant inter-group variation (all adjusted p > 0.5). Effect sizes were small (Cliff’s δ < 0.15), implying minimal clinical difference between TSH strata.

Across all categories, the median LT4 requirement exceeded both guideline thresholds (1.6 and 2.1 µg/kg), indicating systematically higher dosing needs in this cohort. Age analysis revealed a progressive decline in dose with advancing age: <30 years: 2.61 µg/kg, 30–44 years: 2.27 µg/kg, 45–59 years: 2.25 µg/kg, ≥60 years: 2.15 µg/kg. Younger patients required approximately 20–25 % higher doses to achieve comparable TSH suppression.

Conclusion

Indian DTC patients require higher weight-adjusted LT4 doses than current international recommendations for both replacement and suppressive therapy. Although statistical differences across TSH groups were nonsignificant, consistent upward dose shifts across the population underscore the need for population-specific dosing algorithms. Age-related decline in requirement highlights the importance of individualized titration rather than rigid adherence to universal dosage norms.

ABAOCNMB163: Pediatric Differentiated Thyroid Cancer: Risk Stratification, Management Outcomes, and Long-Term Experience from a Single Institution

Srinivas Ananth Kumar, Nandini Pandit, Harish Goyal, Dhanapathi Halanaik

Jawaharlal Institute of Postgraduate Medical Education and Research

Aim

Pediatric differentiated thyroid carcinoma (DTC) is uncommon but often presents with extensive locoregional disease. This study evaluates our institutional experience, highlighting disease burden, AJCC 8th edition staging, ATA risk stratification, cumulative I-131 therapy, treatment response, thyroglobulin (Tg) kinetics, and long-term outcomes.

Materials and Methods

We retrospectively analyzed 20 pediatric patients (<18 years) with histologically proven DTC treated between 2021 and 2025. All underwent total thyroidectomy ± lymph node dissection, followed by risk-adapted I-131 therapy. Staging was assigned per AJCC 8th edition, risk by ATA pediatric guidelines, and treatment response assessed by structural and biochemical criteria. Serial serum Tg/anti-Tg was used for biochemical monitoring. Patients with elevated Tg but negative I-131 scans were classified as TENIS.

Results

The cohort included 15 females and 5 males (M:F ratio 1:3), with a median age of 16 years (range 10–18). Histology was predominantly papillary thyroid carcinoma (95%), with follicular variant in 10%. At presentation, 90% were AJCC Stage I and 10% (n=2) were Stage II with 20% in high risk category. Multifocality was observed in 35%, nodal involvement in 50%, and extrathyroidal extension in 20%. All patients received I-131 therapy with a median cumulative activity of 150 mCi (range 50–450 mCi). Advanced clinical stage (T4aN1bM1) and high-risk ATA profiles were associated with vascular invasion, extranodal extension, and positive surgical margins, requiring higher cumulative I-131 dose.

At a median follow-up of 5 years, 70% achieved excellent response/remission, while 20% had persistent disease (structural or biochemical). Intermediate and low-risk groups (especially unifocal encapsulated variants with minimal invasion) responded well to therapy, exhibited lower cumulative I-131 doses, and declining Tg levels. TENIS syndrome was identified in 2 patients (10%) with discordantly elevated Tg but negative I-131 scans. Serial Tg analysis demonstrated a median baseline stimulated Tg of 45 ng/mL, declining to <1 ng/mL in 60% at last follow-up. Persistently elevated Tg >10 ng/mL correlated strongly with residual/recurrent disease. No patient mortality was recorded. Overall, survival remained excellent, though a subset required prolonged surveillance due to biochemical persistence.

Conclusion

Pediatric DTC in our experience often presented with significant nodal burden and occasional distant metastases but demonstrated excellent long-term survival. AJCC staging was predominantly Stage I, and ATA stratification identified 20% as high-risk. Risk-adapted I-131 therapy achieved high remission rates, though TENIS and persistent Tg elevation remain clinical challenges. These findings reinforce the importance of personalized radioiodine dosing, Tg-based follow-up, and long-term monitoring in pediatric DTC.

ABAOCNMB140: Preoperative localisation and absolute quantification of parathyroid uptake and volume in patients diagnosed with primary hyperparathyroidism using quantitative SPECT/CT

Komalpreet Kaur, Ashwini Sood, B.R. Mittal

PGIMER, CHANDIGARH

Introduction

Parathyroid adenomas are benign tumors of the parathyroid glands that can lead to primary hyperparathyroidism (pHPT). Accurate localization and quantification of these adenomas are crucial for effective surgical intervention. Nuclear medicine techniques, particularly, quantitative SPECT/CT plays an important role in absolute quantification of uptake which is now possible due to the availablity of correction algorithms for attenuation, scatter, CDR, partial volume, motion and also can be calibrated to convert the counts into activity and further to SUV. Aim of the study was to quantify parathyroid adenoma uptake and volume along with its preoperative localisation in patients using quantitative SPECT/CT and Q metrix software.

Materials and Methods

The prospective study was performed in the Department of Nuclear Medicine, PGIMER, Chandigarh. A total of 50 patients (32F:18 M, mean age 38±5 years and range 26-61 years) diagnosed with pHPT were included in this study. 99mTc-sestamibi (10-15Mci) was administered and planar early /delayed regional scan with preoperative early quantitative SPECT /CT was acquired in all the patients. The acquired data was reconstructed and analysed using QMetrix software for parathyroid adenoma uptake, SUV and volume. Concordance correlation coefficient was derived to compare the volume of adenoma obtained by volumetric SPECT/CT and the pathological weight.

Results

Preoperative accurate localisation of parathyroid adenoma was possible in all patients using quantitative SPECT/CT. The median maximum SUVs were significantly higher in adenomas compared to thyroid tissue in early SPECT/CT (26.43 vs. 4.43). A strong correlation was found between SPECT/CT-estimated weight and pathologic weight, with a concordance correlation coefficient (W) 0.72, indicating that quantitative SPECT/CT can reliably predict adenoma volume and weight.

Conclusion

Volumetric Quantification of parathyroid adenomas using nuclear medicine techniques such as Tc-99m sestamibi scintigraphy and SPECT/CT provides valuable information that helps surgeons plan minimally invasive procedures effectively and improves outcomes for patients with primary hyperparathyroidism. SUV derived from parathyroid SPECT/CT using Q.Metrix was reproducible and adenomas were detected with very high sensitivity and specificity.

ABAOCNMB234: Ga-68 Trivehexine PET/CT as a Second-Line Problem-Solver in Sestamibi-Negative or Indeterminate Primary Hyperparathyroidism

Saloni Gadikar [1], Rohit Bulchandani[1], Archita Sharma [1], Sunil HV [1], Bushra Sadeed [1]

¹Department of Nuclear medicine, Narayana Hrudayalaya

Background

Preoperative localization in primary hyperparathyroidism (PHPT) is often challenging when Tc-99m Sestamibi scans are negative or equivocal. Accurate localization is critical for minimally invasive parathyroidectomy. Ga-68 Trivehexine is a novel CXCR4-targeted PET/CT radiotracer with emerging potential to overcome the limitations of conventional imaging.

Aim

To evaluate the diagnostic performance of Ga-68 Trivehexine PET/CT in patients with sestamibi-negative or indeterminate PHPT, including its ability to detect ectopic disease.

Methods

Seven patients with biochemically confirmed PHPT (elevated PTH and hypercalcemia) and negative (n=6) or indeterminate (n=1) sestamibi scans underwent Ga-68 Trivehexine PET/CT.

Results

Ga-68 Trivehexine PET/CT showed focal uptake suggestive of parathyroid adenoma in 4 of 7 patients (57%). One patient demonstrated mild anterior mediastinal sestamibi uptake initially presumed to be a reactive lymph node — however, Ga-68 Trivehexine accurately localized it as an ectopic parathyroid adenoma, which was surgically confirmed. Another patient showed concordant true-positive localization with histopathologically proven adenoma. SUVmax in positive scans ranged from 4.2 to 7.3.

Conclusion

Ga-68 Trivehexine PET/CT demonstrates strong promise as a second-line problem-solving modality in PHPT, particularly in sestamibi-negative or indeterminate cases, with accurate localization of ectopic disease. These early findings support its clinical adoption and warrant larger prospective validation.

ABAOCNMB262: Role of Machine Learning Models in Predicting the Presence of Potential Adenomas in Primary Hyperparathyroidism Patients on F18 Fluorocholine PET-CT

Ritwik Wakankar, Nishikant Avinash Damle, Yamini Dharmashaktu, Bangkim Chandra Khangembam, Nikhil Tandon, Manasvini Bhatt, Arunav Kumar, Angel Hemrom

All India Institute of Medical Sciences

Aim/Introduction

To develop machine learning (ML) models using biochemical data for predicting presence of Fluorocholine (FCH) avid lesions in patients with primary hyperparathyroidism undergoing F-18 Fluorocholine PET-CT.

Materials and Methods

Between August, 2018 to September, 2022, data of 225 patients with biochemically proven primary hyperparathyroidism who underwent FCH PET-CT was retrospectively collected. The primary outcome was to train an ML model that could be used to classify patients and predict the pretest probability of finding an FCH avid lesion on F18 FCH PET-CT. The data was split in a 90:10 ratio into training and testing subsets. After imputing for missing values, Gini Indices were generated and the best-ranked 5 features were selected for cross-validation of the models. 4 ML models (Logistic Regression, Random Forest, Naïve Bayes, Gradient Boosting) were trained using stratified 10-fold cross-validation and then tested against a subset of patients. Model performance was assessed using metrics such as AUC, classification accuracy (CA), F1 score, precision, recall and SHAP plots were generated.

Results

Out of all the models, Naïve Bayes (NB) had a good and realistic performance after training and testing (AUC: 0.741, CA: 0.773, F1: 0.857, Precision: 0.833 and Recall: 0.882). Using the Naïve Bayes (NB) model, a nomogram was generated using the 5 best-ranked features to calculate the pretest probability of getting a positive F18 FCH PET-CT.

Conclusion

Machine learning helped classify primary hyperparathyroidism patients with potential FCH avid lesions using biochemical data. This can help identify patients who will benefit from a F-18 Fluorocholine PET-CT by calculating the pretest probability of finding an FCH avid lesion and help provide personalized patient care.

ABAOCNMB209: METASTASIS IN THYROID GLAND WITH EGFR MUTATION – ¹⁸F-FDG PET SCAN.

Ramya, Vaibhav Jain, MG Vishnoi, Prabhjot Singh, Braj Kishore Singh, Dr Anil Kumar AVS.

Introduction

Thyroid metastasis from lung carcinoma is an uncommon clinical finding, often discovered incidentally on follow-up imaging. 18F FDG PET/CT plays a critical role in identifying and characterizing these lesions, guiding further diagnostic and therapeutic strategies.

Aims

The primary aim of this case report is to highlight the diagnostic importance of PET/CT in detecting thyroid metastases from carcinoma lung, and to demonstrate its contribution to patient management through a multidisciplinary approach.

Case History

A 75-year-old male, previously treated for Stage IIIC Non-small cell lung cancer NSCLC (T4N3) in 2018, presented in 2025 with suspected disease recurrence. His original treatment included concurrent chemoradiotherapy and maintenance durvalumab for left upper lobe adenocarcinoma. Now he presented with hoarseness of voice for which USG neck, Fine needle aspiration from lesion in right lobe of thyroid and cervical lymph node and fluoro-2-deoxy glucose (FDG) PET/CT was performed. The patient underwent total thyroidectomy and modified neck dissection with histopathology confirming widespread metastatic disease. Molecular profiling for BRAF V600E and EGFR S784P mutations was done.

Results

A restaging 18F FDG PET/CT scan revealed: Right cervical lymph nodes (levels II, III, IV) with high FDG uptake; largest 1.3x1.6 cm (SUV max 5.83). FDG-avid, heterogeneous lesion in the right thyroid lobe (2.5x2.4x2.8 cm, SUV max 7.0). Pathology and molecular analysis supported the diagnosis of metastatic lung adenocarcinoma rather than a new primary thyroid tumor.

Conclusion

This case emphasizes the value of 18F FDG PET/CT in diagnosing rare thyroid metastases from lung adenocarcinoma. Metabolic imaging provided early detection and precise localization, influencing timely clinical decisions and multidisciplinary treatment, as demonstrated in this patient with complex oncological history.

ABAOCNMB040: Three years of expertise in a single institution calculating thyroid uptake using a variety of imaging techniques and instruments

G.K. Rangarajan, KRISHNAKUMAR R, ARAVIND KRISHNAMURTHY, ANANDI N

Cancer Institute (WIA) Adyar

Introduction

The era of clinical nuclear medicine began with radioiodine uptake (RAIU) test. The 24 hours RAIU test was introduced in 1950 by Werner et al as a method to appraise thyroid function. Many of the in vivo thyroid function tests are based on the RAIU test. Quantitative evaluation is usually done using thyroid uptake probe and gamma camera gives the qualitative imaging information (Ref-1). Thyroid uptake is a measurement of the ratio of the amount of radioactive material concentrated in the thyroid gland to the amount of radioactive material administered to the patient.

Aim

The aim of this study was to make a quantitative comparison of 24 hours thyroid uptake calculated by Gamma Camera based method (GC) and Thyroid Uptake Probe based method (TUP).

Materials and Methods

The study group consists of 293 patients between 2018-20 of whom 71 were males (13 – 71 years old) and mean age 44.56 years and 222 were females (19 – 71 years old) and mean age 43.45 years. All patients have undergone total thyroidectomy and sent for assessment of neck residue. After a gap 4-5 weeks without Thyroxin replacement, a 50 µCi I-131 Capsule (1.85 MBq) was administered to the patient. As per Institutional protocol, patients had their I-131 neck uptake after 24 hours evaluated by both Uptake Probe and Gamma Camera based methods.

Statistical analysis: Pearson’s correlation coefficient was used to measure the association between the TUP and Gamma values. Wilcoxon’s matched pair rank test was used to test the difference of TUP and Gamma values.

Results

There was a total of 293 matched pair values (%) of TUP versus GC. The difference between TUP and Gamma camera values ranged from 0.0 to 8.4 that was statistically significant (p=<0.001). The TUP and Gamma camera values showed high positive correlation among men, women and all cases together (p<0.001).

Conclusion

The GC based method is not a good substitute for TUP method. If you have to do the thyroid uptake quantification, you have to use dedicated thyroid uptake probe.

ABAOCNMB175: Paneer-Based Ketogenic Preparation with β-Hydroxybutyrate and Machine Learning for Myocardial Suppression in Cardiac FDG PET

Saloni Gadikar ^[1], Rohit Bulchandani^[1], Sunil HV ^[1], Bushra Sadeed ^[1]

¹Department of Nuclear medicine, Narayana Hrudayalaya

Introduction

Adequate suppression of physiological myocardial FDG uptake is essential for diagnosing cardiac sarcoidosis. Standard ketogenic diets are difficult to implement in Indian patients. This study evaluated a paneer-based ketogenic protocol, assessed β-hydroxybutyrate (BHB) and myocardium-to-blood pool (M:BP) SUV ratio as predictors of suppression, and explored a machine learning (ML) model integrating these features.

Methods

Forty-eight patients with suspected cardiac sarcoidosis underwent FDG PET/CT after a paneer-based high-fat, low-carbohydrate diet (30 h), 12 h fasting, and IV heparin. Serum BHB, blood glucose, diabetes status, and dietary compliance were recorded. PET images were visually graded; myocardial SUVmax and blood pool SUVmean were measured to calculate the M:BP ratio. ROC analyses and logistic regression were performed.

Results

Suppression was achieved in 44/48 patients (91.7%). Three non-compliant patients and one compliant patient with high glucose demonstrated inadequate suppression.

Mean BHB was 1.6 ± 0.4 mmol/L in suppressed vs 0.2 mmol/L in unsuppressed (p < 0.01). ROC for BHB showed AUC 1.00 with optimal cutoff ≥0.23 mmol/L (100% sensitivity, 100% specificity).

Glucose had AUC 0.70 with cutoff ≤118 mg/dL.

The M:BP ratio correlated inversely with BHB (r = –0.41, p = 0.004) and perfectly distinguished suppression (AUC 1.00; cutoff ≤1.63).

A logistic regression ML model combining BHB, glucose, diabetes, and M:BP ratio achieved AUC 1.00.

Conclusion

A paneer-based ketogenic diet is effective, culturally acceptable, and well-tolerated. BHB is a reliable biochemical marker, while the M:BP ratio provides robust imaging confirmation. ML integration enhances prediction, supporting personalized preparation protocols and reducing scan failures in cardiac FDG PET.

ABAOCNMB242: ¹³¹Iodine-metaiodobenzylguanidine(MIBG) Myocardial Scintigraphy Profile and its Association with Autonomic Symptoms and Autonomic Function Tests in Patients with Parkinson’s Disease: A Pilot Cross-Sectional Study

Vishnu Balgi, Nandini Pandit, Ramkumar Sugumaran, Velkumary, Harichandra Kumar KT

Jawaharlal Institute of Postgraduate Medical Education an Research

Introduction and Aims

Cardiac autonomic dysfunction and therefore denervation is a well-recognised feature in Idiopathic Parkinson’s disease (PD), whereas most atypical parkinsonian disorders usually spare cardiac sympathetic innervation. Most of the existing studies have employed ¹²³Iodine-MIBG for cardiac sympathetic imaging but its limited availability in India restricts routine application. In this context, ¹³¹I-MIBG offers a feasible alternative. This study aims to evaluate myocardial ¹³¹I-MIBG scintigraphy profile in clinically diagnosed PD patients and correlate these findings with autonomic symptom burden and autonomic function testing(AFT) results, highlighting the potential of cardiac MIBG imaging as a practical diagnostic and prognostic marker in resource-limited settings.

Materials and Methods

This ongoing cross-sectional pilot study is enrolling patients aged 30–70 years with PD diagnosed according to International Parkinson and Movement Disorder Society (MDS) criteria after being subjected to a comprehensive clinical evaluation and examination conducted by specialists in movement disorders. Autonomic symptoms are assessed using the Scales for Outcomes in PD- Autonomic Dysfunction (SCOPA-AUT) questionnaire, and cardiac AFTs are performed by qualified personnel.

Patients undergo ¹³¹I-MIBG myocardial scintigraphy following thyroid blockade and withholding interfering medications. Early and delayed planar images are acquired at 15 minutes and 3 hours post injection respectively. Region of interest (ROI) are drawn on the myocardium and mediastinum and heart-to-mediastinum (H/M) ratios and washout rates (WOR) are calculated. MIBG profile data is assessed for normalcy and association with Hoehn and Yahr (H&Y) stages and any intergroup difference is explored. Further correlations between cardiac MIBG parameters, SCOPA-AUT scores, and AFT results are analysed using Spearman’s rank correlation and non-parametric group comparisons.

Results

Thirteen patients have been recruited to date, with further enrolment ongoing. Preliminary analysis demonstrated a significant negative correlation between delayed H/M ratio and H&Y stage (p = 0.026) and a significant positive correlation between washout rate and disease stage (p = 0.0008), reflecting progressive cardiac sympathetic denervation with advancing Parkinson’s disease. Early H/M ratio showed no significant association. SCOPA-AUT domains and cardiac MIBG parameters showed no statistically significant associations, though a weak positive trend was observed between total SCOPA-AUT scores and early H/M ratio (p = 0.40) and washout rate (p = 0.39). Full analysis after complete enrollment and correlation with autonomic function test parameters is in progress.

Conclusion

This pilot study establishes preliminary reference data on ¹³¹I-MIBG myocardial scintigraphy in Indian patients with Parkinson’s disease. The observed decline in delayed H/M ratio and increase in washout rate with advancing H&Y stage support the presence of progressive cardiac sympathetic denervation starting right from the early clinical stages. These findings underscore the potential of ¹³¹I-MIBG scintigraphy as an important biomarker of disease diagnosis and severity.

ABAOCNMB094: Spectrum and Clinicopathological Outcomes of Cardiac ⁶⁸Ga-FAPI PET/CT Uptake

Srinivasananth Kumar, Harish Goyal, Dhanapathi Halanaik

Jawaharlal Institute of Postgraduate Medical Education and Research

Introduction

Fibroblast activation protein inhibitor (FAPI) PET imaging is an emerging modality in nuclear cardiology, targeting fibroblast activation as a marker of myocardial injury and fibrosis. We aimed to delineate the spectrum of myocardial lesions detected by cardiac FAPI uptake and their clinicopathological outcomes.

Materials and Methods

We retrospectively analysed 100 patients who underwent ⁶⁸Ga-FAPI PET/CT. Cardiac uptake was scored as none (0), low–moderate (1), or intense (2). Uptake metrics (SUVmax, TBR) were correlated with clinical variables including coronary artery disease, prior myocardial infarction, left ventricular ejection fraction (LVEF), and histopathology where available.

Results

Cardiac FAPI uptake was observed in 25% of patients (70% male). Pathologies included post-MI ventricular remodelling, cardiac amyloidosis, infective etiologies, cardiomyopathies, and Erdheim–Chester disease, predominantly with intense uptake (score 2). Mean SUVmax and TBR were 8.5 ± 4.1 and 10.1 ± 1.1, respectively. Intense uptake correlated with lower LVEF (r = –0.62, p < 0.01) and adverse remodeling indices. Histopathology confirmed fibroblast activation and collagen deposition in high-uptake regions. Notably, FAPI uptake localized to areas not well captured by conventional imaging, highlighting early fibroproliferative activity.

Conclusion

Cardiac ⁶⁸Ga-FAPI PET/CT demonstrates a spectrum of myocardial involvement across diverse pathologies, with uptake correlating strongly with adverse remodeling and fibrosis. These findings support FAPI PET as a promising tool for early risk stratification and monitoring of myocardial disease, warranting further prospective validation against established modalities such as cardiac MRI.

ABAOCNMB107: EVALUATION OF RESPONSE TO IMMUNOSUPPRESSION IN CARDIAC SARCOIDOSIS USING Ga-68 DOTANOC PET/CT

Priyanka MN, Indirani Muthukrishnan, Dinesh Kumar Gauthaman, Simon Shelly

Apollo Hospitals, Chennai

Introduction

Sarcoidosis is an inflammatory condition characterized by non-necrotizing granulomas. Although cardiac involvement in sarcoidosis is relatively rare, and has high morbidity and mortality, it is amenable to treatment. Immunosuppression is the primary management in cardiac sarcoidosis(CS). This study was undertaken to evaluate the usefulness of Ga-68 DOTANOC PET/CT (Positron Emission Tomography/Computed Tomography with 68 Gallium DOTA NaI3-octreotide) in assessing the treatment response in CS.

Aim

To evaluate response after immunosuppression in terms of qualitative and semi-quantitative PET/CT parameters in patients with CS and correlate clinically with ejection fraction (EF).

Methods

This prospective observational study included 26 patients diagnosed with CS, who had positive pre-therapy Ga- 68 DOTANOC PET/CT scans. All patients received treatment with immunosuppressants (corticosteroids and/or cyclophosphamide), and later also had post-therapy Ga- 68 DOTANOC PET/CT scans. Qualitative assessment was done by visual analysis. Semi-quantitative parameters using SUVmax and Disease Activity Score (DAS) [ratio of SUVmax of left ventricular myocardium to blood pool SUVmean (descending aorta)], were analyzed for evaluating therapeutic response.

Results

The mean duration of treatment was 14.3 weeks. Visually, 5 patients showed near complete resolution of DOTANOC uptake, and 19 patients showed a varied degree of regression in extent and intensity of DOTANOC uptake on the post-therapy scan. 2 patients showed relatively stable DOTANOC uptake. Significant regression in SUVmax and DAS was observed in 24 patients on the follow-up scan compared to the baseline scan (SUVmax: 1.63 ± 0.49 vs 2.71 ± 1.55, respectively, p-value = 0.001; DAS: 1.9 ± 0.51 vs 3.56 ± 1.23, p-value = 0.001). Relatively stable SUVmax and DAS were documented in one patient, and a marginal increase in both semi-quantitative parameters was observed in another patient; both whom later received alternate therapy and showed regression in DOTANOC uptake in the subsequent follow-up scan. Additionally, the reduction in SUVmax (-0.61, p-value = 0.02) and DAS (-0.73, p-value = 0.002) corresponded to an increase in the EF in 19 patients whose baseline LVEF was less than 50%.

Conclusion

This study demonstrated the usefulness of Ga-68 DOTANOC PET/CT in evaluating therapeutic response by illustrating a reduction in the myocardial inflammatory burden along with a negative correlation between the Ga-68 DOTANOC PET/CT semi-quantitative parameters (SUVmax and DAS) and clinical outcome (EF).

ABAOCNMB201: Tracer outruns the Treadmill: The Incremental Value of Stress MPI in Management of Coronary Artery Disease Patients.

Rohit Bulchandani, Saloni Gadikar, Archita Sharma, Sunil HV, Bushra Sadeed

Deparment of Nuclear medicine, Mazumdar Shaw Hospital, Narayana Hrudayalaya, Bangalore.

Introduction

Patients with angiographically proven coronary artery disease (CAD) exhibit variable outcomes despite optimal medical therapy. Accurate risk stratification in this population remains essential for guiding secondary prevention and revascularization decisions. While treadmill testing (TMT) provides physiological data, stress myocardial perfusion imaging (MPI) offers insight into the significance of angiographically detected lesions. Moreover, LAD involvement is associated with higher rates of anterior MI, heart failure and short-term adverse events, and worse long-term LV function.

Aims

To evaluate the incremental prognostic value of Stress MPI parameters over conventional TMT Bruce protocol variables for guiding management of patients with angiographically proven CAD.

Methods

In this prospective observational study, 73 patients with angiographically confirmed CAD underwent Stress MPI using the TMT Bruce protocol. All were followed for one year for the occurrence of cardiac events.

Independent variables included:

• TMT parameters: METS achieved, exercise duration, double product, ECG changes.

• Stress MPI parameters: perfusion interpretation (ischemia vs normal/infarct) and LAD territory involvement.

• Clinical variables: age and diabetes mellitus.

Multivariate logistic regression was performed across three models:

• Model 1: TMT parameters alone

• Model 2: Stress MPI parameters alone

• Model 3: Combined model.

Model fit (AIC, pseudo-R²) and discrimination (ROC-AUC) were compared to determine incremental value.

Results

18 of 73 patients (24.7%) underwent elective revascularization. Over a 12-month follow-up, none of the 73 patients had a hard event (Death/MI) or an angina/ACS associated hospitalization.

Individual ROC analysis were done for METS and duration of exercise. Lower values of these parameters were associated with higher revascularization rates; however the ROC derived cut-offs (METS<7, Duration<8minutes) did not reach statistical significance (p>0.05).

Model 1 (TMT parameters) showed modest predictive ability (AUC ≈ 0.68, Nagelkerke R² ≈ 0.12).

Model 2 (Stress MPI) improved discrimination (AUC ≈ 0.75).

The final combined model yielded the highest accuracy (AUC ≈ 0.83, Nagelkerke R² ≈ 0.29), representing a statistically significant improvement over TMT parameters alone (bootstrap p < 0.05).

Ischemia on MPI and LAD territory involvement were independent factors that prompted revascularization on multivariate analysis.

Conclusions

In patients with angiographically proven CAD, Stress MPI provides incremental prognostic information beyond exercise-based parameters. In our study, the MPI-guided timely-revascularization improved the overall clinical outcome of these patients. Incorporating MPI findings, especially ischemia and LAD involvement, markedly enhances the management plan in these CAD patients. These findings underscore the value of Stress MPI as a Gatekeeper in the management and follow-up of established CAD.

ABAOCNMB152: ⁶⁸Ga-DOTANOC VS ¹⁸F-FDG PET-CT IN DIAGNOSIS OF CARDIAC SARCOIDOSIS

Archita Sharma ⁽¹⁾, Sunil H.V.⁽²⁾, Bushra Sadeed⁽³⁾, Rohit B⁽⁴⁾, Saloni Gadikar⁽⁵⁾

Narayana Health city, Bommasandra

Aim

To prove that in a well-prepared patient, ¹⁸F- FDG is more sensitive than ⁶⁸Ga-DOTANOC PET-CT in diagnosis of cardiac sarcoidosis.

Introduction

Cardiac sarcoidosis is an infiltrative cardiomyopathy that results from granulomatous inflammation, predominately affecting the myocardium. Approximately 25% of patients with systemic sarcoidosis have cardiac disease involvement. Patients frequently present with symptoms of heart failure, conduction abnormalities, ventricular arrhythmias or sudden cardiac death, all of which can be secondary to numerous disease processes. Additionally, there is no single diagnostic test for sarcoidosis, and while endomyocardial biopsy has a high specificity for cardiac sarcoidosis, it is invasive and less sensitive. Cardiac sarcoidosis is a rare condition with a poor prognosis. However, early diagnosis and intervention can improve outcomes for patients with this infiltrative cardiomyopathy.

Materials and Methods

Day 1:

Rest MPI scan- 99mTc Sestamibi myocardial perfusion SPECT was done followed by ⁶⁸Ga DOTANOC PET-CT: ⁶⁸Ga DOTANOC injection is given i.v. and whole body and cardiac PET-CT images are taken after 60mins. Followed By high protein minimal carbohydrate diet (multiple times).

Day 2: Only high protein minimal carbohydrate diet (multiple times) till 6:30 pm in the evening. Diabetic patients are asked to avoid diabetic medications on Day 2 night and Day 3 morning.

Day 3:

¹⁸F- FDG PET-CT: Patient comes at 7:30am after prolonged fasting. Injection Heparin 50U/kg, 15mins later FDG injection is given i.v. and whole body and cardiac PET-CT images are taken after 60mins.

Results

CASE REPORT: 36 years old male diabetic, hypertensive patient presented with giddiness, intermittent breathlessness and low BP. Holter showed Non sustained VT and first degree AV block with intermittent 2:1 AV block. Coronary angiogram was performed which showed normal coronaries with slow flow. On ECHO, LVEF = 54%. Rest MPI scan followed by ¹⁸F- FDG and ⁶⁸Ga- DOTANOC PET-CT was performed which revealed the following:

Rest MPI- Entire LV myocardium showed adequate perfusion at rest.

DOTANOC PET-CT: Mild ⁶⁸Ga- DOTANOC uptake in posterior interventricular septum.

FDG PET: Focal abnormal FDG uptake in apex, apical anterior, mid anterior, mid anteroseptum, basal anterior and basal anteroseptal segment extending into the adjacent RV wall of LV myocardium and in papillary muscles in the LV cavity, suggestive of early inflammation.

Conclusion

In a suspected case of cardiac sarcoidosis, for a well-prepared patient ¹⁸F-FDG is more sensitive than ⁶⁸Ga-DOTANOC PET-CT.

ABAOCNMB151: BEYOND THE HEART: INCIDENTAL EXTRACARDIAC FINDINGS ON MYOCARDIAL VIABILITY PET/CT

Archita Sharma, Saloni Gadikar, Rohit Bulchandani ⁽³⁾, Bushra Sadeed Sunil H.V.

Department of Nuclear Medicine, Narayana Health City, Bommasandra, Bengaluru

Introduction

Myocardial viability scan is performed to differentiate hibernating myocardium from scarred and non viable myocardium in patients with ischemic cardiomyopathy and left ventricular (LV) dysfunction. It is used to guide decision making regarding revascularization vs medical management. Usually, the Cardiac PET MIP image provides information on FDG avid extracardiac structures. In our study, the transaxial ¹⁸F-FDG PET-CT images were reviewed to detect the incidental extracardiac findings.

Materials and Methods

This is an ongoing prospective study where 70 patients who had undergone myocardial viability ¹⁸F-FDG PET-CT scan in our department have been studied. Resting perfusion images were acquired using an ultrafast cardiac CZT gamma camera. Oral glucose loading was done followed by insulin administration and FDG injection. Regional PET-CT Chest images were acquired in 3D mode 60mins after intravenous injection of 2mCi of ¹⁸F-FDG using a BGO PET-CT scanner. The interpretation of FDG images typically includes a comparison of myocardial perfusion to myocardial metabolism. In our study, transaxial CT, PET and fused PET/CT images were reviewed separately to look for any extracardiac incidental findings.

Results

Of the 70 patients who had undergone the scan, 31 patients had extracardiac findings. 5 of them were FDG avid, 2 had CT features suggestive of malignancy without any significant FDG uptake and 24 patients had benign lesions. FDG avid lesions we found included an exophytic growth in superior pole of right kidney suggestive of renal cell carcinoma, 2 breast mass lesions, lung nodule with spiculated margins and axillary and mediastinal lymphadenopathy. CT features suggestive of malignancy included multiple lung nodules and pleural effusion with suspicious lung nodule. The benign findings ranged from GB calculus, renal calculus, simple hepatic cysts to calcific granulomas, infective and fibro-atelectatic changes in lungs.

Conclusion

A considerable proportion of patients undergoing myocardial viability imaging demonstrate incidental extracardiac findings, including potentially malignant lesions. Hence, it is equally important to carefully view the PET/CT images to detect significant extracardiac lesions in every patient undergoing a myocardial viability scan. Early detection of clinically significant pathology may alter patient management and prognosis.

ABAOCNMB062: Myocardial angiogenesis imaging with ^99mTc HYNIC Cyclo(RGDfk)2 (RGD) SPECT/CT for myocardial viability assessment - An observational study.

Kabilash D, Madhusudhanan Ponnusamy, Subathra Adithan, Avinash Anantharaj, P Ram Shankar

Jawaharlal Institute of Postgraduate Medical Education and Research

Introduction

Obstructive coronary artery disease (CAD) is treated by revascularization. The benefits of revascularization are most notable when hibernating myocardium is present. Myocardial viability is assessed with MIBI and FDG scans, which have some shortcomings. Radiolabelled RGD peptide is used to image areas of neoangiogenesis. This study compares RGD and FDG scans for myocardial viability assessment.

Materials and Methods

In this prospective study, CAD patients considered for revascularization underwent ^99mTc-HYNIC-Cyclo(RGDfk)2 SPECT/CT in addition to the routine myocardial viability imaging. Patterns of RGD distribution were visually analysed. Segmental scores from 0 to 4 were assigned based on the degree of RGD uptake (0 = no uptake and 4 = intense uptake). Viability was defined as reduced perfusion with increased RGD or FDG uptake. Per-segment myocardial viability was compared between MIBI/RGD and MIBI/FDG pairs. Summed rest scores (SRS) and summed RGD scores (SRGS) were also analysed alongside cardiac MRI parameters.

Results

Scans of 33 patients were included for analysis (30 males and 3 females). 22/33 patients had perfusion defects in a total of 150 segments. RGD uptake was noted in 31/33 (94%) patients and 93/150 (62%) perfusion defects. In 37 (24.7%) segments, RGD uptake was more than FDG; in 27 (18%) segments, FDG uptake was more than RGD. The two viability assessment methods were concordant in 57.3% and discordant in 42.7% of segments (Cohen’s &#954; - 0.124). 23 patients had a previous history of MI, and 22 (96%) of them showed focal RGD uptake. 10 patients had no history of MI, and 7 (70%) of them showed diffuse RGD uptake (7/10). A negative correlation was observed between SRS (mean = 19.47, SD = 13.26) and SRGS (mean = 49.5, SD = 14.07), with r = -0.57 (p < 0.001). SRGS showed positive correlations with LVEF (r = 0.43, p = 0.032) and LV Global function index (r = 0.49, p = 0.01).

Conclusion

RGD uptake was higher than FDG uptake in rest perfusion defects. In 43% of the patients, there was discordance in viability assessments made with RGD and FDG scans. RGD uptake was noted in areas with no FDG uptake and, therefore, may not represent viable myocardium. A higher RGD uptake was noted in patients with no severe LV dysfunction.

ABAOCNMB171: Unveiling Hidden Cardiovascular Risk in Chronic Kidney Disease Patients: Insights from Myocardial Perfusion SPECT/CT.

Parnika Tewari, Bhanu Jain, Manish Ora, Prasanta Kumar Pradhan

Sanjay Gandhi Post Graduate Institute Of Medical Sciences

Introduction

Chronic kidney disease (CKD) is an independent risk factor for cardiovascular morbidity and mortality. CKD patients have unusual or silent signs of coronary artery disease (CAD), and traditional risk stratification techniques frequently underestimate the burden of subclinical ischemia. Non-dialysis-dependent moderate to severe CKD patients can not undergo iodinated or gadolinium-based contrast studies for evaluating the coronaries. Myocardial perfusion imaging using single-photon emission computed tomography/computed tomography (MPI-SPECT/CT) provides a non-invasive functional assessment of myocardial ischemia. This study aims to evaluate stress-induced ischemia and cardiac function in CKD patients.

Material and Methods

Patients with CKD (n =50) (mean age: 53.48±11.38 (30-81), Males 42) who underwent MPI-SPECT/CT between January 2023 and July 2025 were included in a retrospective observational study. Risk factors (diabetes, hypertension) and echocardiographic results were documented. Pharmacological stress (adenosine) and rest gated SPECT/CT was performed using Tc-99m tetrofosmin. Perfusion defects (ischemia or scar) and ejection fraction (EF) were evaluated.

Results

The main complaints were dyspnea on exertion, breathlessness, or atypical chest pain. Forty-six (92%) of patients had comorbidities, diabetes (21, 42%), hypertension (25, 50%), and tobacco chewers (1, 2%). Anemia was seen in 48% (n = 24) of the population. Twenty-one patients (42%) had stress-induced ischemia, which included mild (10,48%), moderate (4, 19%), and severe (7, 33%). Reduced ejection fraction (EF<60%) was noted in stress and rest images in 24 (48%) and 20 (40%) patients. Two patients (4%) underwent PTCA, and the rest of the patients were kept on medical management.

Conclusion

This study shows a high prevalence of cardiovascular risk factors among CKD patients. MPI-SPECT/CT detected a high prevalence of myocardial ischemia (42%), even in the absence of typical angina on exertion. Reduced EF is the likely contributory factor for DOE in patients without inducible ischemia. The high prevalence of ischemia and reduced cardiac function highlights the significant cardiovascular burden in the CKD population, hence, the possible mortality. Routine integration of MPI-SPECT/CT for ischemic heart disease assessment is recommended in this susceptible population.

ABAOCNMB179: Reassessing the utility of Segmental Myocardial Thickness & RWMA on 2D-Echocardiography in Myocardial Viability assessment: A Validation Study Using Cardiac FDG-PET/CT in Indian Patients.

Yogananda YT, Sameer Taywade, Rajesh Kumar, Surender Deora

AIIMS JODHPUR

Introduction

Coronary artery disease (CAD) is one of the most prevalent cardiac conditions in India. Myocardial ischemia can progress from stunning and hibernation to apoptosis, necrosis, fibrosis and scarring ultimately leading to heart failure. CAD results in infarct related wall thinning, regional wall motion abnormality (RWMA) and increased LV volume. In this study we evaluated the role of myocardial wall thickness & RWMA as a preliminary screening parameter on 2D-echocardiography in assessing myocardial viability, using cardiac FDG PET-CT as the reference standard in the Indian population.

Materials and Methods

This prospective study was conducted in patients with known or suspected CAD. Recruited patients subsequently underwent 99m Tc-Sestamibi SPECT & cardiac FDG PET-CT for assessment of myocardial viability. 17 segment model was used for analysis. Thickness of 578 segments was measured by 2D-echo, and viability was assessed with cardiac FDG-PET/CT, which was then correlated with segmental thickness. ROC curve analysis was carried out using IBM SPSS v 26 to determine the optimal cut-off value of myocardial segmental thickness for assessment of viability. Sensitivity and specificity were also calculated for RWMA alone, as well as for combined RWMA and wall thickness assessments, applying both OR and AND rules.

Results

A total of 578 segments were analysed in the assessment of myocardial viability from 34 patients. 160 segments were graded as non-viable by FDG PET-CT and 418 segments were graded as viable. RWMA alone showed a sensitivity of 93.1% and specificity of 72.7%, while wall-thickness ≤ 5.5 mm demonstrated sensitivity of 85.9% and specificity of 76.2%. When combined using the OR rule sensitivity increased to 95.6% but specificity decreased to 68%. Using the AND rule sensitivity dropped to 73.8%, with specificity rising to 89.9%. These results illustrate the trade-off between sensitivity and specificity when combining echocardiographic measures for myocardial viability assessment.

Conclusion

2D-echocardiographic wall-thickness measurement, being simple, cost-effective, and widely accessible represents a valuable preliminary screening tool for myocardial viability assessment particularly in resource limited settings with no PET/CT facility, while FDG PET-CT remains the definitive standard. The wall thickness ≤ 5.5 mm offers a balanced diagnostic performance, with good sensitivity (85.9%) and reasonable specificity (76.2%). Integrating RWMA and wall thickness enhances the confidence in confirming non-viability with markedly improved specificity (89.9%) at the cost of reduces sensitivity.

ABAOCNMB141: Tc-99m MIBI MYOCARDIAL WASHOUT RATE IN PATIENTS WITH CHEST PAIN AND ITS CORRELATION WITH MPS FINDINGS

B Surekha Surekha, Tekchand Kalawat, Ramya Priya Rallapeta, Rajasekhar D

Sri Venkateswara Institute of Medical Sciences

Introduction

In literature, many studies have documented the association of mitochondrial dysfunction (MD), with chronic systemic and degenerative disorders. MD can be assessed by Mitochondrial DNA number analysis and mitochondrial metabolite quantification. In nuclear cardiology, Tc-99m MIBI is used for demonstrating blood flow heterogenicity in CAD, by utilising its property to localise in mitochondrial membrane. The current study is designed to evaluate the utility of washout rate % (WR %) for assessment of myocardial MD in-vivo.

Aim

To evaluate and correlate the Tc-99m MIBI myocardial washout rate in patients presented with chest pain undergoing MPS.

Material and Methods

A total of 68 patients with chest pain undergoing SPECT MPS between November 2022 and March 2025 were included for the study. A two-day protocol, rest followed by adenosine-induced stress studies was performed. Each study was followed by delayed imaging at 4 hours. The Tc-99m MIBI WR% was derived from early (1-hour) and delayed (4-hour) images for both studies. Association of WR% with risk factors, comorbidity status and MPS findings were evaluated.

Results

Of n=68 patients, 29 (43%) were male and 39 (57%) were females. Females presented at a younger age as compared to male patients (57.36 ± 10.38 Vs 61.38 ± 9.48 years). Perfusion defect on MPS were noted in 42 (61.8%) patients, while 26 (38.2%) had normal perfusion. Mean WR% in rest and stress study showed no statistically significant difference (p=0.23). Females demonstrated significantly higher WRR% compared to males (p=0.008). A higher WR% was noted in elderly age group, patients with high BMI, diabetics and hypertensives patients. On further analysis based on MPS 1 findings, a higher WR% was noted in patients with fixed defect + RR pattern, double/ triple coronary artery vascular territory involvement and those with large degree of perfusion defects.

Conclusion

Washout of Tc-99m MIBI from cardiomyocytes, due to loss of membrane potential, is observed in CAD patients. Our study reveals a higher WR% of Tc-99m MIBI is associated with underlying ischemia and severity of CAD, and may serve as a valuable, non-invasive imaging marker for detection of mitochondrial dysfunction in patients with CAD.

ABAOCNMB080: “Ga-68 DOTANOC PET-CT versus F-18 FDG PET-CT in Response Assessment of Cardiac Sarcoidosis – Preliminary Results of an Ongoing Pilot Prospective Study”

Chakshine S, Chetan D. Patel, Kh. Bangkim Chandra, Aman Tilak, Anushna S Babu, Priyanka Gupta, *Ambuj Roy, *Neeraj Parakh, *Sourabh Agstam, *Deepti S, *Nirmal Ghati, ^Sanjeev Kumar, ^Vineeta Ojha.

Department of Nuclear Medicine, *Cardiology & ^Cardiac Radiology, All India Institute of Medical Sciences, New Delhi

Introduction

Cardiac sarcoidosis (CS) is an important cause of arrhythmias and sudden cardiac death. F-18 fluorodeoxyglucose (F-18 FDG) PET/CT, though remains a valuable tool in the evaluation of CS, is limited by variable physiological myocardial uptake and complex patient preparation protocols. Gallium-68 DOTA-NaI-octreotide (Ga-68 DOTANOC) PET/CT, by targeting somatostatin receptors, offers a specific, logistically simpler and more interpretable alternative for imaging myocardial inflammation in CS.

Aim

To compare F-18 FDG and Ga-68 DOTANOC PET/CT in assessing response in patients with cardiac sarcoidosis.

Materials and Methods

A total of 7 patients with suspected or established CS were included in this study, who underwent resting Technetium-99m Sestamibi (Tc-99m MIBI) myocardial perfusion SPECT, followed by baseline and follow-up dual tracer PET/CT, comprising F-18 FDG and Ga-68 DOTANOC performed within 2 weeks of each other to ensure comparability of tracer uptake. CS was diagnosed based on the revised guidelines given for diagnosis of CS by Japanese Circulation Society (JCS) 2017. Patients were clinically followed to assess symptomatic response alongside imaging findings. Follow-up scans with F-18 FDG and Ga-68 DOTANOC were assessed in parallel and concordance analysis was performed using descriptive statistics.

Results

For response assessment, patients whose scans show reduction in intensity or complete resolution of tracer uptake were considered responders, while those with persistent tracer uptake were considered non-responders. Despite standard patient preparation, follow-up F-18 FDG PET/CT scan of one patient was inconclusive (uninterpretable) due to intense physiological uptake, whereas Ga-68 DOTANOC PET/CT showed complete resolution. This scan was deemed equivocal and excluded from agreement analysis. Among the follow-up scans of remaining 6 patients, both F-18 FDG and Ga-68 DOTANOC classified 4 patients as responders and 2 as non-responders, showing perfect concordance (100%) with no discordant cases.

Conclusion

F-18 FDG and Ga-68 DOTANOC PET/CT demonstrated 100% agreement in identifying responders and non-responders on follow-up imaging of CS. Notably, in the follow-up scan of one patient where F-18 FDG was equivocal, Ga-68 DOTANOC resolved the uncertainty and clearly classified the patient as a responder, underscoring its practical advantage in challenging scenarios. Thus, Ga-68 DOTANOC adds incremental value as a complementary tracer for response assessment in CS, particularly in situations where strict dietary preparation is difficult and F-18 FDG scans are inconclusive.

ABAOCNMB149: Yttrium-90 Resin Microsphere Transarterial Radioembolization in Hepatocellular Carcinoma: Initial Experience with Scout Dose–Based Lung Shunt Estimation and Dosimetry

Jasim Jaleel, Mangu Srinivas Bharadwaj, Amar Mukund, Sandeep Singh, Akshima Sharma, Nikhil, Shiv Kumar Sarin

Institute of Liver and Biliary Sciences, New Delhi

Introduction and Aims

Yttrium-90 (Y-90) transarterial radioembolization (TARE) is an effective locoregional therapy for hepatocellular carcinoma (HCC). In the absence of a gamma camera in our resource-limited setting, we employed a low-dose pretreatment Y-90 resin microspheres as a scout dose for estimating the lung shunt fraction (LSF) and dosimetry. This study aimed to report our initial single-centre experience with Y-90 TARE, focusing on feasibility, dosimetry correlation, and treatment response.

Materials and Methods

Between May 2025 and September 2025, thirty-two consecutive patients were evaluated for Y-90 TARE. After injection of the Y-90 scout dose, PET/CT images were acquired, and LSF and lung dose (LD) calculations were performed using MIM-SurePlan Y90 dosimetry software. Patients with excessive LSF were excluded. Post-therapy PET/CT scans were performed to assess the distribution and dosimetry of the Y-90 microspheres. Treatment response was evaluated using LIRADS and RECIST 1.1 criteria on follow-up triple-phase computed tomography.

Results

Of the 32 patients, four were excluded owing to increased LSF (>20%), and one was diagnosed with intrahepatic cholangiocarcinoma. Of the remaining 27 HCC patients, four underwent streamlined TARE without LSF estimation, and the remaining 23 patients received standard scout dose–based dosimetry-guided treatment. The mean activity of the scout dose administered was 0.5 GBq (SD - 0.1). The mean pre-therapy LSF was 5.3 %, with a corresponding mean pre-therapy LD of 7.4 Gy. The mean treatment activity of Y-90 delivered was 3.45 GBq (SD-1.5) with a mean delivered tumor dose of 384.2 Gy (SD-185). The mean post-therapy LSF was 4.7 % with a corresponding LD of 5.9 Gy. A significant correlation was observed between pre- and post-therapy LSF (r = 0.81, p < 0.01) and LD (r = 0.84, p < 0.01). At the time of analysis, follow-up imaging was available for 15 patients, demonstrating that 10 of them showed a complete response (LR-TR nonviable), 4 showed partial response (LR-TR viable), and one showed stable disease, resulting in an objective response rate (ORR) of 93.3%. Early adverse effects included fatigue, abdominal pain, nausea, vomiting, chest pain and fever, which were self-limiting.

Conclusion

Y-90 TARE with pretreatment scout dose-based LSF estimation and individualised dosimetry is safe and feasible in real-world tertiary care practice. The encouraging ORR and correlation between pre- and post-therapy LSF and LD support the robustness of the dosimetry approach.

ABAOCNMB241: Predictive Value of Hepatobiliary Scintigraphy–Derived Functional FLR in Post-Hepatectomy Liver Failure

Sumeet Suresh Malapure, Sibi Oommen, Naveena Kumar A N

Kasturba Medical College, Manipal

Introduction, Aims

Post-hepatectomy liver failure (PHLF) remains a major cause of morbidity and mortality following hepatic resection. Accurate estimation of the future liver remnant (FLR) is crucial for preventing postoperative hepatic insufficiency. Conventional CT or MRI volumetry provides only anatomical estimates, which may not accurately represent true hepatic function, particularly in patients with heterogeneous parenchymal disease or chemotherapy-induced hepatic injury. Hepatobiliary scintigraphy (HBS) using 99mTc-mebrofenin enables quantitative functional mapping of hepatic segments, allowing determination of both total and segmental functional liver reserve. This study aimed to evaluate the predictive value of HBS-derived functional FLR in forecasting PHLF and to compare its clinical utility with conventional volumetric assessment.

Materials and Methods

A retrospective analysis was performed on patients who underwent major hepatectomy(right/ left hepatectomy or extended hepatectomy) after preoperative HBS-derived FLR assessment. Patients with incomplete data or non-resective procedures were excluded. The functional contribution of the remnant liver was quantified from dynamic hepatobiliary scintigraphy, and postoperative liver function was evaluated using the International Study Group of Liver Surgery (ISGLS) criteria. Patients were classified based on whether they developed PHLF within 7 postoperative days. Diagnostic indices, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and the area under the ROC curve (AUC), were calculated using extrapolated data from a cohort of 110 patients.

Results

Among 110 evaluated patients, 27 (24.5%) developed PHLF. HBS-derived functional FLR accurately identified 7 true positives, 80 true negatives, 3 false positives, and 20 false negatives. The calculated diagnostic performance was as follows: sensitivity 25.9%, specificity 96.4%, PPV 70.0%, NPV 80.0%, accuracy 79.1%, and AUC 0.61. A significant correlation was observed between lower preoperative functional FLR values and postoperative hepatic dysfunction, confirming that diminished functional reserve on scintigraphy reliably reflected compromised postoperative hepatic performance.

Conclusion

Hepatobiliary scintigraphy-derived functional FLR provides a highly specific and clinically meaningful tool for predicting PHLF. Although sensitivity remains modest, its excellent specificity and predictive accuracy make it superior to conventional volumetric estimation in identifying patients at risk for postoperative hepatic failure. Integration of functional FLR assessment into preoperative surgical planning can enhance patient selection, optimize safety, and improve postoperative outcomes in hepatectomy candidates.

ABAOCNMB217: Future Liver Remnant Augmentation Before Major Liver Resections; Assessment of Future Remnant Liver Function using Hepato- Biliary Scintigraphy and CT Volumetry- A Prospective Cohort Study

Santosh Kannur, Spruha P, Sunita Gupta, Tanmay Dutta, Tara Tripathy, B.D Pattnaik, Kanhaiyalal Agrawal

AIIMS BHUBANESWAR

Background

Major liver resection requires future liver remnant (FLR) augmentation in majority of the cases. The published data from India on this is sparse. This study prospectively evaluates volumetric and functional changes in the FLR following portal vein embolization (PVE), using CT volumetry and 99mTc-Mebrofenin hepatobiliary scintigraphy (HBS).

Materials and Methods

Data was collected (August 2024 to August 2025) from a prospectively maintained database of patients undergoing major liver resections (more than three segments) following FLR augmentation. PET-CT and staging laparoscopy was performed to rule out metastasis before portal vein embolization (PVE). CT volumetry was done before and four weeks after PVE using Myrian software. Hepatic vein embolization (HVE) was done if FLR was still inadequate. Functional gain was assessed using hepatic scintigraphy. Patients will undergo 99mTc-Mebrofenin HBS before and after 1 month of PVE. Sequential dynamic Images were acquired under the gamma camera for 30 minutes after iv. injection of 99mTc Mebrofenin. In HBS, the mean liver perfusion was calculated using Xeleris 4.0 software on the planar images.

Results

Thirty-three patients were planned for major hepatic resection. Nine (27%) had adequate FLR at baseline, while 24 (73%) had inadequate FLR. Of the latter group, 5 patients were found to have metastatic disease at staging laparoscopy and were offered palliative therapy. Nineteen patients underwent liver augmentation with PVE.

One patient succumbed to severe cholangitis during the waiting period. One patient was excluded and Four patients had completed augmentation but were still within the 4-week post-PVE interval at the time of analysis. Thirteen patients were analyzed post-PVE.

On HBS, the mean total liver plasma flow increased slightly from 854 ml/min (range: 348–1400) before PVE to 861.3 ml/min (range: 405–1670) after PVE, with a mean FLR functional gain of 10.6%.

CT volumetry showed a mean FLR volume increase of 177 cc, despite the total liver volume gain of only 48 cc. The mean degree of hypertrophy was 11.96% (range: 3–31%), with a mean kinetic growth rate of 2.99%/week (range: 0.7–7.5).

Six patients have undergone definitive liver resection to date: 2 for hepatocellular carcinoma, 3 for gallbladder carcinoma, and 1 for hilar cholangiocarcinoma. Median age was 47 years (range: 33–65). One patient developed grade B post-hepatectomy liver failure (PHLF), but no in-hospital mortality occurred.

Conclusion

Liver augmentation helps in achieving both volumetric and functional gain of liver. HBS is a simple useful modality in assessment of change in functional gain of liver.

ABAOCNMB200: ¹⁸F-FDG PET/CT in Hepatobiliary IgG4-Related Disease: Diagnostic Value and Systemic Involvement Patterns

Komal Preet¹, Rajender Kumar¹, Harmandeep Singh¹, Anish Bhattacharya¹, Sunil Taneja², BR Mittal¹, Ritambhra Nada³

¹Department of Nuclear Medicine, PGIMER, Chandigarh, ²Department of Hepatology, PGIMER, Chandigarh, ³Department of Histopathology, PGIMER, Chandigarh,

Introduction

Immunoglobulin G4-related disease (IgG4RD) is a multisystem inflammatory disorder that can affect various organs. Hepatobiliary involvement can closely mimic malignancy, complicating diagnosis. While ¹⁸F-FDG PET/CT is a promising modality in systemic IgG4-related disease (IgG4RD), its utility in hepatobiliary IgG4-related disease (HB-IgG4RD) remains underexplored. This study aimed to characterize the imaging patterns, extent of systemic involvement, and diagnostic accuracy of ¹⁸F-FDG PET/CT in patients with suspected HB-IgG4RD.

Materials and Methods

We retrospectively analyzed 20 patients suspected of HB-IgG4RD who underwent whole-body ¹⁸F-FDG PET/CT from 2019 to 2024 at a tertiary center to evaluate systemic involvement. Clinical, biochemical, and imaging data were reviewed, with histopathology/follow-up as the gold standard. PET/CT findings were evaluated for the pattern of involvement, number of organs affected, comparison of SUVmax, and correlation with final diagnosis. Statistical analysis was performed using the Mann–Whitney U test, with p < 0.05 considered significant.

Results

A total of 20 patients (12 males, 8 females) with a median age of 44 years (range: 32-65 years) clinically and biochemically suspected of hepatobiliary IgG4RD were retrospectively analyzed. The most common presenting symptoms were abdominal pain (16/20 patients, 80%), jaundice (4/20 patients, 20%), fever (1/20 patients, 5%), and back pain (1/20 patients, 5%). Final histopathology/clinical follow-up confirmed IgG4RD in 16 (80%) patients and malignancy in 4 (20%) patients. A higher SUVmax was noted in patients diagnosed with malignant etiologies as compared to benign IgG4RD disease (median 8.3 vs 5.4, p = 0.09). Among patients with confirmed HB-IgG4RD on ¹⁸F-FDG PET/CT, isolated HB involvement was noted in 2 of 16 patients (12.5%), whereas 14 of 16 patients (87.5%) demonstrated multi-organ involvement. The most frequent findings included diffuse uptake in the CBD/CHD/hepatic ducts (14/16 patients, 87.5%), salivary glands (11/16 patients, 68.8%), pancreas (6/16 patients, 37.5%), lymph nodes (8/16 patients, 50%), gall bladder/gall bladder fossa (2/16 patients, 12.5%), prostate (2/16 patients, 12.5%), and kidneys (1/16 patients, 6.2%). ¹⁸F-FDG PET/CT demonstrated an overall diagnostic accuracy of 90% for HB-IgG4RD.

Conclusion

¹⁸F-FDG PET/CT is a non-invasive tool with a high diagnostic accuracy for evaluating suspected HB-IgG4RD cases, which can detect multisystem involvement, aiding in differentiation from malignancy based on the pattern of involvement.

ABAOCNMB091: EVALUATION OF COLLIMATOR-DETECTOR-RESPONSE FOR ABSOLUTE QUANTIFICATION AND DOSIMETRY OF 177LU/188RE- LABELLED RADIOPHARMACEUTICAL USING QUANTITATIVE SPECT/CT: ADDRESSING THE TECHNICAL CHALLENGES IN IMAGE-BASED DOSIMETRY

Komalpreet kaur, gaurav gupta, sejal chopra, jaya shukla, rajender kumar, vijayta. D. Chadha, bhagwant rai mittal

PGIMER, Chandigarh

Introduction

Absolute quantification of radiopharmaceutical is essential for dosimetry analysis in theranostics. An accurate model of the collimator-detector-response (CDR) is required since image quantification takes into account the probability of the photon emitted from the source and its contribution to voxel of the resulting image. Aim of the study was to analyse the effect of CDR in image quantification using different collimators and estimate absorbed dose based on quantitative SPECT/CT in hepatocellular carcinoma (HCC) patients receiving 188Re-microsphere selective intra-radionuclide therapy (SIRT) and in neuroendocrine tumor (NET) patients receiving ¹⁷⁷Lu-DOTATATE.

Materials and Methods

The different phantom studies were performed in the Department of Nuclear Medicine, PGIMER, Chandigarh. Quantitative SPECT/CT was acquired with 120 projections (20s/projection) for theragnostic radionuclide 188-Re/177Lu with appropriate photopeak and scatter window. The acquired data was reconstructed in three set. In First set corrections for CDR, Scatter and attenuation were applied in reconstruction. In second set recon was done with only AC and in third set no corrections were applied. Quantitative accuracy in terms of activity concentration recovery was assessed for different set of collimators available i.e LEHR and HEGP. A single time point regional quantitative SPECT/CT was acquired in 10 HCC patients and 10 NET patients after one therapy cycle and analysed for image based absorbed doses using MIRD schema.

Results

In first set, absolute activity concentration were measured to be within 11% (HEGP) and 32% (LEHR) of the expected value for 188Re and 18% (HEGP) and 52% (LEHR) of the expected value for 177Lu. In the second set, there was significant contribution of scatter photons and the activity concentration were overestimated. In third set activity concentration was erroneously estimated. This trend was observed for both the sets of collimators but HEGP was observed to be more accurate in 188Re-quantification. Since we do not have MEGP collimator, HEGP was used for 177Lu-quantification. The first set of CDR modelling was then used for activity quantification and dosimetry calculations in HCC and NET patients undergoing therapy which also correlated with the clinical response. An average mean absorbed dose of 2.4±7.2 mGy/MBq and 28.7 ± 19.2 mGy/MBq was delivered to tumor in one ¹⁷⁷Lu-DOTATATE and 188Re-microsphere SIRT cycle respectively.

Conclusion

The tested device provided accurate activity recovery within 11% (188Re) and 18% (177Lu) of the expected values for HEGP; these performances are comparable to current generation PET/CT systems. Quantitative accuracy was maintained with varying distance from detector. Pre therapy as well as post therapy patient specific image-based dosimetry can be performed easily when SPECT quantification protocol and acquisition is standardised.

ABAOCNMB095: Predicting Hepatic Reserve via Machine Learning Integration of FDG PET, Liver Biochemical Tests, and Clinical Variables

Prakash Singh, Manish Ora, Vineet Mishra, Yogita Khandelwal, Bela Jain

King George's Medical University

Introduction

Evaluating hepatic reserve is essential in patients with hepatocellular carcinoma (HCC) to inform therapy choices and forecast outcomes. Traditional scoring systems, such as Child-Pugh classification and Albumin-Bilirubin (ALBI) grade, are prevalent; nevertheless, they are constrained by subjectivity and inadequate incorporation of tumor burden or metabolic activity. Progress in quantitative imaging and machine learning (ML) presents the opportunity to improve predictive accuracy by integrating functional imaging biomarkers, metabolic data, and clinical signs into a cohesive model.

Aim

The objective is to create and evaluate machine learning models for predicting hepatic reserve utilizing a composite dataset of fluorodeoxyglucose positron emission tomography (FDG PET) measurements, liver biochemical assays, and clinical factors, while also comparing their efficacy to traditional scoring methods.

Material and Methods

This retrospective study evaluated 50 patients with hepatocellular carcinoma (HCC) who underwent FDG PET/CT imaging, comprehensive liver function testing, and detailed clinical assessment. The predictor variables included PET-derived metrics (SUV max, SUV mean, metabolic tumor volume [MTV], total lesion glycolysis [TLG], Ki Patlak), biochemical measurements (albumin, bilirubin, INR, AST, ALT, AFP), and clinical indicators (ascites, encephalopathy, tumor burden). The outcome variables were Child-Pugh class, ALBI grade, and continuous liver function scores. Data preprocessing encompassed the imputation of absent values, standardization, and feature selection. A variety of machine learning algorithms were assessed, including logistic regression, XGBoost, and support vector machines, with hyperparameter optimization conducted using cross-validation. The evaluation of model performance was conducted by ROC-AUC, accuracy, calibration, and decision curve analysis, while feature importance was ascertained using SHAP values.

Results

Models that incorporate PET measures alongside biochemical and clinical characteristics surpassed conventional clinical ratings in differentiating hepatic reserve. The XGBoost model attained the highest prediction accuracy, with a ROC-AUC of 0.85 for Child-Pugh categorization and robust calibration across risk strata. FDG Ki, MTV, ALBI score, and components of the Child-Pugh classification have been identified as significant predictors. The ML-based composite severity measure exhibited enhanced net reclassification relative to Child-Pugh and ALBI individually, underscoring its clinical applicability.

Conclusion

Machine learning models that incorporate imaging, biochemical, and clinical characteristics offer a reliable and objective method for forecasting hepatic reserve in hepatocellular carcinoma (HCC). These models may enhance risk classification, optimize treatment strategies, and improve prognostic evaluations beyond traditional scoring systems.

ABAOCNMB224: Evaluation of Clinical Efficacy, Survival Outcomes, and Dosimetric Correlation of ¹⁸⁸Re-N-DEDC/Lipiodol Transarterial Radionuclide Therapy (TART) in Patients with Inoperable Hepatocellular Carcinoma (HCC)

Naresh Kumar¹, Shamim Ahmed Shamim¹, Priyanka Gupta¹, Geetanjali Arora¹, Shivanand G. ¹, Shalimar¹, Viju Chirayil², Suresh Subramanian², Madhava B. Mallia², Parul Thakral³, Ishita B. Sen³

¹ All India Institute of Medical Sciences, New Delhi, ² BARC, Mumbai, ³ Fortis Memorial Research Institute, Gurgaon

Aim/Introduction

HCC is the sixth most frequent malignancy and the third leading cause of cancer death worldwide. Nearly 90-95% of HCC patients have cirrhosis at the time of diagnosis, contributing to a poor prognosis. Transarterial delivery of ¹⁸⁸Re-lipiodol, labelled with DEDC, developed indigenously by BARC, combines the therapeutic efficacy of β-emitting ¹⁸⁸Re (E_βmax 2.1 MeV, ~11 mm tissue penetration) with cost-effective, on-site preparation making it a promising TART agent. Despite promising initial outcomes, the real-world efficacy, survival and dosimetric data remain limited. The present study aimed to evaluate the dosimetric correlation with clinical efficacy and survival outcome in patients undergoing ¹⁸⁸Re-N-DEDC/Lipiodol TART for inoperable HCC.

Materials and Methods

Thirty-nine patients (36 males, 3 females; mean age 57.9 ± 10.9 years) with radiologically and biochemically confirmed inoperable HCC (ECOG ≤2, Child-Pugh A/B) were enrolled. The therapeutic activity (4612 MBq) was prescribed based on partition model and administered via super-selective trans-arterial injection under fluoroscopic guidance. Post-therapy dosimetry was performed using Hybrid Dosimetry Module™. Response was assessed at 2 and 6 months using mRECIST and serum AFP levels.

Results

The median prescribed tumor-absorbed dose was 80 Gy; estimated tumor absorbed was 77.7 Gy (15.50 mGy/MBq). No significant difference was observed between pre- and post-therapy tumor absorbed doses (p = 0.5479). The post-therapy median absorbed dose to whole liver, normal liver parenchyma, and lungs was 1.77 mGy/MBq, 0.26 mGy/MBq and 0.73 mGy/MBq. At 2 months (n=36), radiological ORR and DCR were 47.2% and 83.3%; biochemical ORR and DCR were 61.1% and 77.8%. ECOG performance improved in 41.6%. Tumor absorbed dose correlated significantly with both radiological and biochemical responses. ECOG and baseline bilirubin showed significant association with clinical response. At 6 months follow-up (n=14), radiological ORR and DCR were 50% and 71.4%; biochemical ORR and DCR were 42.8% and 57.1%. BCLC stage and Child-Pugh score correlated with radiological outcomes. Overall survival remained high (94.9%) till 6 months, while progression free survival declined over time, 60.4% in 6 months. Disease progression was most common in advanced-stage patients, with early-stage patients showing the best outcomes. Among various clinical, biochemical, and dosimetric parameters, no statistically significant correlation with overall survival was observed, except for the radiological, biochemical, and clinical response outcomes, which showed a meaningful association with survival.

Conclusion

¹⁸⁸Re-N-DEDC/Lipiodol TART demonstrated encouraging response rates, and meaningful survival benefit in inoperable HCC. Tumor-absorbed dose and treatment response parameters showed significant correlation with clinical efficacy and survival outcomes.

ABAOCNMB249: Comparison of Manual and Software-Based (MIMS) Future Liver Remnant Estimation using Hepatobiliary Scintigraphy in patients undergoing Major liver resections

Sibi Oommen, Harinandan Baiju, Naveena Kumar A N, Sumeet Suresh Malapure

Manipal College of Health Professions

Introduction and Aim

Accurate estimation of the future liver remnant (FLR) is essential for preoperative hepatic assessment. Automated software tools such as MIM Software (MIMS) provide reliable FLR quantification but are often expensive and not readily available in all nuclear medicine facilities. To address this limitation, our department initiated manual FLR calculation using standard formulae and compared these results with MIMS-derived values to assess their accuracy and feasibility as a cost-effective alternative.

Materials and Methods

FLR was calculated manually and using MIMS in patients undergoing hepatobiliary scintigraphy. Statistical comparison included Pearson and Spearman correlation analyses, Bland–Altman assessment of bias and limits of agreement, Lin’s concordance correlation coefficient (CCC), and the intraclass correlation coefficient (ICC) to determine intermethod agreement.

Results

Manual and MIMS-derived FLR values demonstrated a very strong correlation (Pearson r = 0.94, p < 0.001; Spearman ρ = 0.88, p < 0.001). Bland–Altman analysis showed a small positive bias of 0.28 ± 0.59 with 95% limits of agreement ranging from –0.87 to +1.43. The ICC (0.94) and Lin’s CCC (0.93) indicated excellent concordance. MIMS consistently yielded slightly lower FLR values compared to manual calculations, reflecting a mild systematic underestimation.

Conclusion

Manual FLR calculation demonstrates excellent correlation and agreement with MIMS-based estimation. Given its accuracy, reproducibility, and negligible cost, manual FLR quantification represents a practical and reliable alternative to automated software in resource-limited nuclear medicine settings.

ABAOCNMB057: Fine-Tuning GPT-2 for Semi-Automated Generation of PET-CT Reports in Breast Cancer

Dibya Prakash ^[1], *, Archi Agrawal ^[2], V Rangarajan ^[3], Manoj Kumar ^[4], *

^{[1 - 3]} Advanced Centre for Treatment, Research, and Education in Cancer, Tata Memorial Centre, Mumbai, ^[4] Amity University, Noida, UP

Introduction

Positron Emission Tomography-Computed Tomography (PET-CT) is an indispensable diagnostic modality in oncology, neurology, and cardiology. Accurate and detailed nuclear medicine reports are essential for clinical decision-making. However, manual report generation is time-consuming and subject to inter-observer variability. Recent advances in transformer-based language models provide opportunities to semi-automate and assist in standardizing clinical reporting. This study presents a semi-automated PET-CT report generation system using a fine-tuned GPT-2 model on clinical PET-CT report datasets.

Materials and Methods

A dataset of 886 report sections from 170 patients was compiled, covering both region-specific reports (brain, head and neck, thorax, abdomen and pelvis, musculoskeletal) and whole-body reports. The dataset comprised 85 patients with Ca breast cancer and 85 normal cases, ensuring a balanced representation of pathological and non-pathological findings. Systematic preprocessing was applied to clean and structure the text. The GPT-2 language model was fine-tuned with optimization strategies to ensure efficient training on an NVIDIA GeForce RTX 4050 GPU. Training was originally planned for 25 epochs but incorporated early stopping criteria to avoid overfitting. Early stopping was triggered after three consecutive epochs of minimal loss improvement (threshold: 0.005). At convergence (epoch 16.56), training was halted. Additional measures included dynamic batch size scaling and optimized GPU memory management to prevent memory-related interruptions. An interactive interface was developed for clinical integration.

Results

The fine-tuned GPT-2 model demonstrated strong performance in semi-automated report generation. At epoch 16.56, evaluation metrics achieved:

• ROUGE-1 score: 0.902375

• BLEU score: 0.786398

• METEOR score: 0.884618

These results indicate accurate reproduction of clinical report content, with stable training convergence achieved before the initially planned 25 epochs.

Discussion

The study demonstrates the potential of transformer-based models for nuclear medicine reporting. A fine-tuned GPT-2 model showed feasibility for semi-automating PET-CT report generation using both region-specific prompts (e.g., “Generate PET-CT report for Thorax”) and whole-body reports. The preprocessing pipeline standardized terminology (e.g., “FDG-avid”) and filtered invalid reports, ensuring clean training data, while an interactive interface enabled prompt-based, real-time generation. This approach reduces manual workload and variability, improving efficiency and consistency in clinical workflows. Results aligned with prior GPT-based radiology studies (e.g., Nakaura et al., 2024; Zhang et al., 2025), with high alignment to reference reports (ROUGE-1 0.902375). Integration with RIS/PACS could allow direct linkage to scans, and EHR integration may enable personalized outputs. While limitations include truncation of long reports and reliance on a single-institution dataset, future work could explore larger models, multimodal integration, and automated prompt generation from PET-CT images to move toward full automation.

Conclusion

This work shows that a fine-tuned GPT-2 model can semi-automate PET-CT report generation with high accuracy. Trained on 886 clinical reports, it supports region-specific and whole-body outputs through a prompt-based interface, backed by robust preprocessing. At 16.56 epochs, metrics (ROUGE-1 = 0.902, BLEU = 0.786) indicate strong performance, reducing reporting time and variability. The model serves as a drafting assistant with potential RIS/PACS and EHR integration, though larger datasets, advanced models, and image-based prompts will be needed for full automation.

ABAOCNMB219: Classification of Brain 18F-FluoroDOPA PET CT scans using radiomics based machine learning in patients with movement disorders

Abhishek Behera, Meghana Prabhu

Amrita Institute of Medical Sciences

Introduction and Aims

Dopamine transporter (DOPA) PET imaging plays a pivotal role in evaluating patients with movement disorders, particularly for differentiating degenerative parkinsonism from non-degenerative causes. While qualitative visual interpretation remains the gold standard, machine learning (ML)–based radiomics can offer reproducible and automated diagnostic support. The aim of this study was to develop and compare multiple supervised ML models, built using no-code platforms, to classify DOPA PET scans of the brain as positive or negative for abnormal striatal uptake.

Materials and Methods

A total of 53 patients undergoing DOPA PET brain scans for evaluation of movement disorders were retrospectively included. PET images were pre-processed on 3D Slicer. Segmentation of the bilateral basal ganglia was performed using global thresholding (maximum entropy or manual global thresholding), followed by manual refinement. Radiomics features were extracted using PyRadiomics v3.1, compliant with the IBSI framework, yielding >800 features including wavelet-filtered descriptors.

The radiomics dataset was imported into Orange Data Mining for supervised ML. Five classifiers were tested: Logistic Regression, Support Vector Machine (RBF), Random Forest, AdaBoost, and XGBoost. The workflow included:

• Preprocessing: Imputation of missing values and z-score scaling.

• Feature selection: Two approaches were tested — univariate filter based and L1-based selection.

• Model training and validation: Stratified cross-validation (2–3 folds depending on cla ss balance). Best models were identified based on AUC.

Results

On the Basal Ganglia (BG) dataset compared towht gold standard (NM Physicians with more than 10 years experience), the following results were obtained:

• Random Forest: AUC 0.86, accuracy 0.83, sensitivity 0.82, specificity 0.84.

• Logistic Regression: AUC 0.86, accuracy 0.81, sensitivity 0.80, specificity 0.82.

• SVM (RBF): AUC 0.85, accuracy 0.80, sensitivity 0.79, specificity 0.81.

• AdaBoost: AUC 0.84, accuracy 0.78, sensitivity 0.77, specificity 0.80.

• XGBoost: AUC 0.84, accuracy 0.78, sensitivity 0.76, specificity 0.80.

Feature selection consistently highlighted radiomic descriptors linked to textural heterogeneity (e.g., Busyness, Dependence Non-Uniformity, High Gray Level Emphasis).

Conclusion

This study demonstrates the feasibility of using no-code ML pipelines for radiomics-based classification of DOPA PET scans in movement disorders. Among multiple tested algorithms, Random Forest and Logistic Regression achieved the highest AUC (0.86) with balanced sensitivity and specificity. Automated ML approaches can complement visual interpretation, potentially improving diagnostic confidence and reproducibility in clinical practice.

ABAOCNMB146: N-13 Ammonia Production on GE PETtrace 800 in F-18 Production target (Nb25)Radio synthesis, Quality Control & Preclinical Study

Saikat Nandy¹, Sutapa Rakshit¹, Yogita Shete ^1,3, Arjun Gopalkrishna² & Nawab Singh Baghel¹

¹ MCRPhPS, Radiation Medicine Centre (G), BARC, Parel, Mumbai-400012, ² Medical Cyclotron Facility, BRIT, Parel, Mumbai-12, ³ Animal House Facility, RMC (M&G), BARC, Parel, Mumbai-12

Introductions

¹³NH₃ is one of the oldest FDA approved PET radiopharmaceutical for evaluation of myocardial perfusion for clinical assessment of cardiac disorders. Larger scale production using nano molar range ethanol containing water as target material, dedicated cyclotron target and synthesis module is widely studied one. Production of pharmaceutical grade ¹³NH₃ production by irradiation of 10nM ethanol containing water in F-18 production target in GE PETtrace 800 and PET/CT imaging study in rabbit showing cardiac uptake is first time reported.

Materials and Methods

STEP-1: 10 nM Ethanol containing water was irradiated in Nb25 target in GE PETtrace 800 upto 35 µA for 30 min. STEP-II: Delivery of produced ¹³NH₄⁺ along with target water to HOT CELL in fully automated synthesis module. STEP-III: Trapping of 13NH4+ in pre conditioned CM cartridge. STEP-IV: Elution with physiological saline and collection in sterile, BET free vials through 0.22µ filters. Quality control tests like clarity, pH, Radiochemical purity (Radio TLC: Water: Acetone: Acetic Acid 3:2:1(V/V/V), Radionuclide purity (Half-life Method), BET assay (Nexgen PTS) and sterility tests were performed. Presence of HAVAR foil generated radio metals and quantification was carried out by HPGe method.

Cardiac uptake confirmation was done by PET/CT imaging study in healthy rabbit. Considering the short half-life of N-13 and we need to keep the rabbit in no-movement condition, the anesthesia time and the amount of radioactivity injected were off great concern. ~ 5mci of N-13 ammonia in saline was injected through ear vein. Anesthesia (Ketamine/xylazine) was given according to body weight (~ 2.6 Kg). PET/CT images were carried out 10 min post injection in Phillips Discovery TOF.

Results

The procedure is fully automated and total synthesis and QC time is 10 min. The whole procedure is carried out after obtaining regulatory permission. ¹³NH₃ is clear, colourless, free of any suspended particle, BET free and sterile. Radiochemical purity is > 95% (R_f : 0.7). Half Life (t ½) is 10.39±0.21 confirming the formation of ¹³NH_3. Presence of HAVAR foil generated radiometals in final product showed the presence of mainly Co isotopes but of very few KBq level. PET/CT imaging study showed very distinct uptake in heart and very rapid blood clearance almost neglible uptake in any other organs. This confirms that the species is 13NH4+ considering the uptake mechanism of ⁸²Rb-Chloride, ^99mTc-MIBI.

Conclusion

Pharmaceutical grade ¹³NH₃ can easily be produced in GE PETtrace800 with standard F-18 production target (Nb25).

ABAOCNMB273: Application of machine learning in predicting response to neoadjuvant therapy in patients with esophageal cancer using baseline F-18 FDG PET/CT

Vignesh H, Poovendhan Mathiyazhagan, Harish Goyal, Dhanapathi Halanaik

JIPMER

Introduction/Aim

Radiomics involves analysis of image data as numerical values. The features thus generated are utilised for personalised treatment planning, prognostication and molecular/genomic subtyping. Patients with locally advanced malignancies of the esophagus and gastro-esophageal junction (GEJ) undergo neoadjuvant chemo-radiotherapy. Here we aim to train and validate a machine learning model to classify patients into responders (complete response and partial response) and non responders (stable disease and progressive disease) based the F-18 FDG PET/CT performed during their initial evaluation.

Methodology

A retrospective search was performed and the baseline and response assessment F-18 FDG PET/CT scans for patients with biopsy proven carcinoma esophagus performed between January 2024 to June 2025 were collected. Segmentation, pre-processing and feature extraction was performed using 3d Slicer software. Feature selection and model building was performed using Orange software.

Results

39 pairs of baseline and response assessment scans of patients with carcinoma of esophagus and GEJ were collected. Of these, 7 were excluded due to non availability/poor quality. 851 features were extracted, 773 showed an intraclass correlation (ICC) of >0.9, which were ranked using analysis of variance (ANOVA); and the top 20 features were selected. Support vector machine (SVM), random forest and logistic regression models were used which performed with an area under curve (AUC) of 0.726, 0.548 and 0.256 respectively on an ROC curve. The SVM model had a classification accuracy (CA) of 74%.

Discussion

Our model was modestly successful in predicting treatment response in patients with esophageal cancer undergoing neoadjuvant therapy. Although meticulous measures are taken to avoid over-fitting, a small sample size remains a drawback of this study. In addition, the modalities and agents for neoadjuvant therapy were heterogeneous and decided by the treating physician. Further training on a larger dataset is required to develop this model; and validate its generalizability

ABAOCNMB174: Nanocomposite-Embedded Peelable Films for Dual-Action Radiation Shielding and Surface Decontamination

Shivanand Bhushan, Srinivasulu Maddassani

Academy of Higher Education Manipal – Karnataka India

Background

The increasing use of radionuclides in biomedical laboratories necessitates dual-protection technologies capable of radiation attenuation and surface decontamination. Current practices lack integrated solutions.

Aim/Objectives

To design peelable films embedded with high-Z nanocomposites that simultaneously reduce radiation exposure and enable effective removal of surface contamination.

Methods

Synthesis of lead oxide and tungsten oxide nanoparticles (20–50 nm) was optimized for uniform dispersion into a polymeric peelable matrix. Film thickness, curing conditions, and adhesion–cohesion balance were studied to maximize both shielding and decontamination. Comparative assessment with conventional swab and detergent cleaning was performed.

Results

Optimized nanocomposite films showed >45% reduction in surface dose rates at 99mTc energy range and >70% decontamination efficiency across glass, steel, and polymer surfaces. Peelability was achieved within 10–12 minutes of curing without leaving residues.

Conclusions

The dual-action peelable nanocomposite film represents a practical, scalable, and cost-effective solution to reduce operator exposure and manage spill-contamination in radiopharmacy settings.

ABAOCNMB135: Production and radiochemical separation of no-carrier-added ¹⁶¹Tb for preparation of ¹⁶¹Tb-labeled bisphosphonate amide of DOTA

Priyalata S. S. Shetty^1,2, Sharad P. Lohar², Khajan Singh², Sudipta Chakraborty^1,2

¹Homi Bhabha National Institute, Anushaktinagar, Mumbai - 400094, India, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai

Introduction

In recent years, ¹⁶¹Tb [T_1/2 =6.9 d, E_β^-_(av.) = 154 keV, E_γ= 74.6 keV (10%)], has emerged as an improved alternative to ¹⁷⁷Lu in targeted cancer therapy. Along with its β^- emission of comparable energy to that of ¹⁷⁷Lu, ¹⁶¹Tb also emits Auger and conversion electrons with significant yields, potentially enhancing its cytotoxicity. Herein, we report production of no-carrier-added (NCA) ¹⁶¹Tb via ¹⁶⁰Gd (n, γ) ¹⁶¹Gd → ¹⁶¹Tb route using enriched Gd targets and its radiochemical separation by extraction chromatography using LN₂ and DGA resins first time in India. The clinical suitability of NCA ¹⁶¹Tb was demonstrated by preparation and evaluation of [¹⁶¹Tb]Tb-BPAMD complex (BPAMD = Bisphosphonate amide of DOTA) for targeting metastatic skeletal lesions.

Materials and Methods

NCA ¹⁶¹Tb was produced by neutron irradiation of enriched [¹⁶⁰Gd]Gd₂O₃ (62.8% and 98.2 % in ¹⁶⁰Gd) targets at a flux of ~ 1 × 10¹⁴ n/cm²/s in Dhruva research reactor for 28 days and radiochemically converted to [¹⁶¹Tb]Gd(NO₃)₃. Distribution ratios (K_d) of Tb³⁺ and Gd³⁺ ions on LN₂ resin were evaluated. Radiochemical separation of NCA ¹⁶¹Tb was achieved by sequential elution of Gd and Tb using 0.25 M and 1 M HNO₃, respectively and obtained as [¹⁶¹Tb]TbCl₃ using DGA column. Radionuclidic (RNP) and radiochemical purity (RCP) were assessed by γ-spectrometry and radio-thin layer chromatography (radio-TLC). Radiolabeling of [¹⁶¹Tb]Tb-BPAMD was optimized by varying ligand concentrations and reaction times at 100° C. In vitro stability of the formulation was monitored in physiological saline at 37⁰C up to 7 days and its binding affinity for hydroxyapatite (HA) was evaluated by radiotracer uptake studies.

Results

¹⁶¹Tb in NCA form was separated from the bulk Gd matrix using LN₂ resin with ~80% overall yield and ~98 % RCP. The %RNP of separated ¹⁶¹Tb were ~99.84 % and ~99.93% for 62.8% and 98.2% enriched targets respectively. [¹⁶¹Tb]Tb-BPAMD was obtained with >95% radiochemical yield using 100 µg BPAMD and 400 MBq [¹⁶¹Tb]TbCl₃ post 45 min incubation at 100⁰ C. The complex showed >97 % in vitro stability up to 7 d and >95% uptake on HA within 5 min equilibration.

Conclusion

This study presents an efficient methodology for radiochemical separation of clinical-grade NCA ¹⁶¹Tb. As a proof of concept, radiolabeling of ¹⁶¹Tb with BPAMD was achieved with high radiochemical yields and in vitro stability. These findings highlight the potential of ¹⁶¹Tb as a promising alternative to ¹⁷⁷Lu in the treatment of micro-metastatic bone lesions.

ABAOCNMB087: ¹⁷⁷Lu-labeled HER2-receptor Targeting Monomeric and Dimeric Peptides

Sonal Gupta^a,c, Manoj Kumar^a, Krishna Mohan Repaka^d, Ajit A. Kengar^c, Drishty Satpati^*a,b

^aRadiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India; ^bHomi Bhabha National Institute, Mumbai, India; ^cKET’s V. G. Vaze College, Mumbai University, India; ^dBoard of Radiation and Isotope Technology, Mumbai, India

Introduction

Breast cancers associated with over-expression of HER2-receptors tend to be metastatically aggressive. Precise and timely identification is crucial for appropriate treatment of HER2-positive breast cancer. With an aim of designing HER2-receptor targeting radiolabelled tracer, monomeric peptide, DOTA-rL-A9 and its dimer DOTA-(rL-A9)₂ were synthesized, radiolabelled with Lu-177 and investigated for their efficacy.

Materials and Methods

Monomeric, DOTA-rL-A9 and dimeric peptide, DOTA-(rL-A9)₂ were synthesized manually on solid phase. Peptides were purified and characterized by mass spectrometry. Radiolabeling with ¹⁷⁷LuCl₃ was performed by incubation at 90°C for 20 min followed by analysis using RP-HPLC. Cell binding studies were performed in HER2-expressing human breast carcinoma SKOV3 cells. Stability in human serum (48 h) and metabolic stability in mice urine and blood (2 h) was determined.

Results

Peptides, DOTA-rL-A9 and DOTA-(rL-A9)₂ could be synthesized in >99% purity and 20% yield. Radiolabelling yield of ¹⁷⁷Lu-DOTA-rL-A9 and ¹⁷⁷Lu-DOTA-(rL-A9)₂ was >95%. Respective partition coefficient (log P_o/w) values were -3.73 ± 0.01 and -3.30 ± 0.01, indicating high hydrophilicity of radiopeptides. Binding affinity of ¹⁷⁷Lu-DOTA-(rL-A9)₂ [35.22 ± 18.2 nM] was observed to be higher than of ¹⁷⁷Lu-DOTA-rL-A9 [65.32 ± 2.45 nM] Both the radiopeptides were stable in human serum (>95% intact) as well in mice blood and urine (>90% intact).

Conclusions

Monomeric rL-A9 peptide could be successfully dimerized during solid phase synthesis and obtained in high purity. Peptides, DOTA-rL-A9 and DOTA-(rL-A9)₂ could be radiolabeled with Lu-177 in high yields. High binding affinity observed for ¹⁷⁷Lu-DOTA-(rL-A9)₂ suggests increased affinity of the dimeric peptide towards HER2-expressing cells. The two radiopeptides demonstrated high metabolic stability. Further, pharmacokinetics and tumor uptake shall be further ascertained by performing in vivo biodistribution studies.

ABAOCNMB118: One tool for the win: Arabinogalactan coated gold (Au-198) nanoparticles, a multifunctional nano-system to treat hepatocellular carcinoma

Sanjay Bharati¹, Vasumathi Ramesh¹ Rashika Sharma¹, Suva1axmi.S¹, Maya P. Shetty¹, Anjali Singh

¹Department of Nuclear Medicine, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India.

Introduction

Hepatocellular carcinoma (HCC) is one of the major causes of global mortality. The available treatment strategies have limited therapeutic efficacy and are technically challenging. The use of gold nanoparticles for treatment of HCC is currently being explored. However, certain disadvantage of nanoparticles such as non-specific biodistribution, inefficient target selectivity, and toxicity hinders their clinical application. Therefore, improvement in targeting strategy of gold nanoparticles to hepatoma cells is considered important and relevant. Asialoglycoprotein receptors (ASGPR) are considered as an ideal target for hepatocyte-specific delivery, therefore gold nanoparticle is coated by arabinogalactan ligands that can specifically target ASGPR receptors and helps to overcome the challenges of non-specific targeting during therapy.

Aim

In the present study we aimed to synthesis arabinogalactan coated gold nanoparticles (AGAuNPs) where arabinogalactan helps in target specific delivery and gold nanoparticles serves as therapeutic agent.

Material and Methods

AGAuNPs was synthesized by using Turkevich method. The obtained complex was assessed for its chemical characteristics using UV-Visible spectroscopy, DLS, TEM, FTIR, XRD and EDX.

Results

The results obtained from UV-Vis, FTIR and elemental distribution suggested that gold NPs have been successfully coated with arabinogalactan by substituting -OH groups of arabinogalactan. The size of 30 nm determined by TEM confirmed AGAuNPs suitability to target hepatoma cells. Further, the favourable XRD characteristics of AGAuNPs indicated that the synthesized AGAuNPs can be employed not only as radiopharmaceutical but also as radiosensitizers for PTT/PDT.

Conclusion

Therefore, these results confirmed that AGAuNPs could be a potential multimodal-multifunctional agent that can be employed for receptor-targeted radionuclide therapy of HCC, offering promising therapeutic outcomes.

ABAOCNMB199: Studying In-vivo Pharmacokinetics of [¹⁷⁷Lu]Lu-Doxorubicin Loaded Radiopaque Microspheres: A Potential Agent for Radio-Chemoembolization of HCC

Sayan Das^1,2, Suresh Subramanian², Mohini Guleria^2,3, Saikat Biswas¹, Santanu Dhara¹*, Tapas Das^2,3*

¹Biomaterials and Tissue Engineering Group, School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302, West Bengal, India, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India, ³Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India

Introduction

In trans-arterial chemoembolization (TACE), micron-sized drug eluting beads are injected in the tumor feeding hepatic artery to treat hepatocellular carcinoma (HCC). Despite broad clinical acceptance, the high doses and rapid release of chemotherapeutic agents often lead to an immune suppressive tumor microenvironment, as well as hepatobiliary and renal toxicity. In this context, this study aims to - (i) prepare a novel radio-chemotherapeutic agent for combination therapy of HCC, and (ii) development of a biocompatible radiopaque microsphere (RadMS) designed for sustained in-vivo drug release.

Materials and Methods

The sulphonated radiopaque microspheres (sRadMS), containing chitosan moiety, was prepared using emulsion-crosslinking process followed by sulphonation. Briefly, 4% (w/v) chitosan solution (5 mL) was added in drop-wise manner to paraffin oil (30 mL) with constant stirring (1200 rpm) at 60 ^oC temperature for 5 min. Subsequently, freshly prepared 2,3-Diiodosuccinaldehyde (540 mM, 600 µL) was added to the reaction mixture to crosslink the chitosan microdroplets. The microspheres were collected by centrifugation and washed with acetone and isopropanol. The radiopacity of the microspheres was studied using MicroCT and the crosslinking density was measured using Ninhydrin assay following the standard protocols. Further, these microspheres were sulphonated using 0.1 (M) H₂SO₄ and 70% Isopropanol (30 mins, RT, 400 rpm) to get sRadMS, which were characterised using XPS, FT-IR, SEM, TEM-EDX and BET analyses. To study the in-vitro and in-vivo drug loading and release profile, p-NCS-Bz-DOTA-Doxorubicin was synthesized by coupling Doxorubicin with p-NCS-Bz-DOTA (37 ^oC, pH = 9.5, 24 h, purified by semi-preparative HPLC, characterized by FT-IR spectroscopy and LC-MS) and subsequently radiolabeled with ¹⁷⁷Lu (18.5 MBq), which resulted formation of [¹⁷⁷Lu]Lu-DOTA-Dox (characterized by radio-HPLC). The biodistribution and planar scintigraphy study of [¹⁷⁷Lu]Lu-DOTA-Dox loaded sRadMS was conducted in healthy Wister rats (post portal-vein administration) to investigate the in-vivo release profile of [¹⁷⁷Lu]Lu-DOTA-Dox from the sRadMS.

Results

The sRadMS was found to be highly spherical in nature [diameter= 25±7.6 µm (dry) and 53±10.9 (wet)] with 83±3.4 % crosslinking density. The BET surface area of sRadMS was 186.20 m².g^-1 and the microspheres were mesoporous in nature (<d_pore> = 4.65 nm). The radiolabeling yield and radiochemical purity (7 days post-preparation in PBS, pH 7.4) of [¹⁷⁷Lu]Lu-DOTA-Dox were found to be >95% and >90%, respectively. The [¹⁷⁷Lu]Lu-DOTA-Dox adsorption on sRadMS follows Freundlich chemisorption (R²=0.987) confirming the ion-exchange drug loading. The in-vitro (PBS, pH= 5.6 & 7.4) and in-vivo release of the [¹⁷⁷Lu]Lu-DOTA-Dox follows Higuchi kinetics, confirming sustained release over several days. [¹⁷⁷Lu]Lu-DOTA-Dox loaded sRadMS shows >78% retention in healthy Wister rat liver post 7 d of portal vein administration. Overall, the in-vitro and in-vivo results of [¹⁷⁷Lu]Lu-DOTA-Dox loaded sRadMS confirms its potential to be used as a radio-chemoembolization agent in HCC with sustained drug release profile.

ABAOCNMB170: Calibration and protocol setting in Gamma Camera for Dosimetry and it’s application in 177 Lu Patients.

Hepziba R, Alamelu

Apollo Speciality Hospital

Introduction

Dosimetry is an invaluable tool in radiopharmaceutical therapy. It provides critical insights into radiation dose distribution, organ toxicity and enables personalized treatment planning. Calibration and protocol setting is essential for the application of dosimetry software. Our study explains the setting of dosimetry software (MIMS) and it’s uasage in 177-Lu patients.

Aim

To explain methods and techniques involved to calibrate and align existing gamma camera SPECT-CT system for performing dosimetry calculation in I131 and LU177 and it’s application in Lu patients.

Materials and Methods

1 mCi of I 131 was taken in a 2 mL syringe and placed in a point source holder. Gamma camera parameters were changed in Siemens Symbia (Intevo) Gamma camera, according to vendor specific settings as described in the table. Specific Quantitative parameters were generated. The same procedure was repeated for 1 mCi of Lu177. Dosimetry was performed on 25 post therapy patients (10 PSMA, 13 DOTA, 1 FAPI) in our institution from April 2024- April 2025 (Age range 38- 63, male : female 16 :9).

Results

After the protocol setting, specific quantitative parameters such as scatter correction, correction factor and resolution recovery factor for I-131 and 177 Lu were generated. Dosimetry was then performed in post 177 Lu therapy patients. Radiation abdorbed doses were generated at two time points for the target (tumor) and critical organ (kidneys, bone marrow etc).

Conclusion

Calibration and protocol setting is an important step in setting of Dosimetry to render accurate and reliable values of absorbed dose. Dosimetry needs to be inculcated in therapy patients, for a more personalized and optimum treatment plan. Our study explains the setting up of dosimetry software and it’s usage in therapy patients in our institute.

ABAOCNMB082: PET-CT based differentiation and prognosis estimation of lung cancer subtypes: Foundation models outperforming radiomics

Parveen Kundu, Rajat Vashistha, Sandeep Kumar, Harmeet Singh, Lauren Aoude, Sandra Brosda, Andrew Barbour, Viktor Vegh

Rohtak Nuclear Medcare Imaging Therapy and Research Center, India

Introduction

In lung cancer accurate differentiation between adenocarcinoma (ADC) and squamous cell carcinoma (SCC) is critical, as these histological subtypes differ significantly in their underlying biology, treatment strategies, and clinical outcomes. While histopathology remains the diagnostic gold standard, it is invasive, prone to sampling errors, and not always feasible in routine practice. Positron emission tomography–computed tomography (PET-CT), combined with computational analysis of imaging biomarkers, offers a promising non-invasive approach. This study aimed to evaluate the potential of conventional radiomics and a deep learning–based foundation model (DINOv2) for non-invasive differentiation of ADC and SCC, and to explore their prognostic relevance in the Indian cohort [1].

Methods

Pre-treatment PET-CT images from patients with biopsy-confirmed ADC and SCC were retrospectively analyzed (n=54). Conventional radiomic features were extracted from PET and CT images, while high-dimensional image embeddings were generated using the fine-tuned DINOv2 foundation model [2]. Feature sets were statistically evaluated (two-sample t-tests) for their ability to differentiate ADC and SCC. Unsupervised clustering was performed to group patients based on extracted features, and Kaplan–Meier survival analysis was conducted to assess the prognostic significance of these clusters [3].

Results

Both radiomic and DINOv2 features demonstrated significant discriminatory power in distinguishing ADC from SCC. Among radiomics, first-order CT features such as entropy, uniformity, and mean intensity, along with PET-derived median and mean intensity, showed statistically significant differences between ADC and SCC (p < 0.05). DINOv2-derived features exhibited substantially stronger differentiation capability, with significance levels reaching p < 0.000001, underscoring the superior representational strength of deep learning based embeddings. Survival analysis further revealed that patient clusters defined by both radiomic and DINOv2 features were associated with distinct survival outcomes, suggesting prognostic utility beyond subtype classification.

Conclusion

These findings suggest that integrating deep foundation models with conventional radiomics could enhance diagnostic accuracy and enable personalized treatment planning. Further validation in larger, multi-centre cohorts is required to confirm these results and support clinical translation into decision-support systems for lung cancer management.

ABAOCNMB051: Revisiting Salivary Scintigraphy: AI-Enhanced Quantitative Assessment of Warthin’s Tumor

Tanvi Sarwal, Tejesh P. Singh, Deepa Kumar, Aditi Khurana, Padma Namgyal, Ravinder Sethi

Department of Nuclear Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India

Introduction

Salivary gland scintigraphy, once widely used for functional assessment of parotid pathology, has been overshadowed in the era of cross-sectional and hybrid imaging. However, its ability to provide unique physiologic insights remains underutilized. Advances in artificial intelligence (AI) now permit automated, rapid, and reproducible analysis of time-activity curves, potentially revitalizing this modality in contemporary clinical practice. We present an atypical case of Warthin’s tumor evaluated with AI-assisted salivary scintigraphy, highlighting its role in a complex diagnostic scenario.

Methods

A 53-year-old male presented with gradually enlarging swelling over left cheek for 4 years. The swelling was mixed cystic-solid in consistency, and measured 3x3 cm. MRI revealed a lesion in the superficial lobe of the left parotid gland, with diffusion restriction and post-contrast enhancement (type 3 dynamic curve), favoring a neoplastic etiology. Laboratory results were unremarkable. The patient had undergone right superficial parotidectomy 30 years earlier, however histopathology were not available. The patient was referred to Nuclear Medicine for salivary scintigraphy.

Dynamic scintigraphy was performed in anterior projection for 20 minutes following intravenous administration of 5 mCi of 99mTc-pertechnetate. A sialogogue, lemon juice, was administered orally at 10 minutes to stimulate salivary excretion. Images were first interpreted visually, followed by AI-assisted quantitative analysis to calculate uptake and washout parameters for objective interpretation.

Results

No tracer activity was observed in the right parotid fossa, consistent with prior surgery. The left parotid gland demonstrated high uptake, representing 44% of total gland activity, with an uptake-to-thyroid ratio of 31. However, secretion following stimulation was markedly reduced at 17%, indicating impaired excretory function.

AI-assisted curve analysis confirmed these findings, showing a progressive rise in tracer activity, a brief dip immediately after lemon juice administration, and a paradoxical rise thereafter, rather than the expected decline. Bilateral submandibular glands showed near-normal uptake (left 14%, right 15%) and secretion (left 31%, right 40%), supporting that dysfunction was localized to the left parotid gland. Histopathology from ultrasound-guided biopsy of the left parotid gland confirmed Warthin’s tumor, demonstrating papillary and cystic structures lined by bilayered oncocytic epithelium with lymphoid stroma.

Conclusion

AI-assisted quantitative scintigraphy enhanced diagnostic confidence by providing objective measurements and validating visual findings in an atypical presentation of Warthin’s tumor. Incorporating AI into salivary scintigraphy may enhance accuracy, reduce subjectivity, and re-establish its role as a precise functional imaging tool, especially in challenging diagnostic settings.

ABAOCNMB131: Feasibility and Performance Analysis of a Locally Deployed LLM (phi3:3.8b) for Paediatric 99mTc-MDP Bone Scan Report Mining

¹Shivam Arora, ²Vibhanshu Pandey,¹ Jagrati Chaudhary,³ Param Dev Sharma, ¹Chetan D Patel, ¹Rakesh Kumar

¹Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, ²Department of Information Technology, Maharaja Agrasen Institute of Technology, New Delhi, ³Department of Computer Sciences, SGTB Khalsa College, University of Delhi, New Delhi

Background

Large language models (LLMs) are increasingly investigated for clinical report interpretation, yet their application in nuclear medicine remains largely unexplored. Pediatric 99mTc-methylene diphosphonate (MDP) bone scans play a pivotal role in evaluating metastatic disease, benign skeletal conditions, and treatment response. This study reports a feasibility and performance analysis of a locally deployed lightweight LLM, phi3:3.8b, for structured information extraction from pediatric bone scan reports.

Methods

Thirty anonymized pediatric 99mTc-MDP bone scan reports acquired between January and August 2025 were retrospectively analyzed. A comprehensive set of 48 domain-specific classification questions was developed, covering scan adequacy, metastatic characterization, benign skeletal findings, infection, uptake patterns, extraskeletal observations, comparative disease burden, impression statements, and advanced reasoning tasks. Each report was processed using a zero-shot prompting strategy, where the model was instructed to answer “Yes,” or “No,”. Model predictions were benchmarked against expert-annotated ground truth. Performance metrics included accuracy, precision, recall, specificity, F1-score, and confusion matrices, aggregated across all questions.

Results

The feasibility analysis demonstrated that phi3:3.8b could reliably address basic descriptive questions. The model achieved perfect performance for certain core queries, such as confirming whole-body scan performance, scan quality, or general identification of metastases (e.g., Q1, Q3, Q5; accuracy = 1.00, F1 = 1.00). However, its capacity to handle nuanced clinical reasoning was limited. For several questions relating to lesion distribution, benign versus malignant differentiation, and therapy-related insights, precision and recall dropped to zero. Intermediate performance was observed for questions involving disease progression (Q15, F1 = 0.50), oligometastatic versus widespread disease assessment (Q37, F1 = 0.86), and aggressive uptake patterns (Q38, F1 = 0.44). When averaged across all 48 questions, the model demonstrated an overall accuracy of 0.85, but substantially lower precision (0.21), recall (0.13), and F1-score (0.15). This suggests that while the model was feasible for extracting simple structured data, it was inadequate for advanced interpretation requiring contextual reasoning.

Conclusion

This feasibility study demonstrates that a locally deployed lightweight LLM (phi3:3.8b) can be effectively applied for automated mining of pediatric bone scan reports, particularly for basic descriptive tasks. However, its limited sensitivity and reasoning capabilities restrict its current clinical utility. The findings underscore the need for domain-specific fine-tuning, advanced prompting strategies, and hybrid AI–clinician workflows.

ABAOCNMB129: Validating Locally Deployed Large Language Model for Automated Structured Data Extraction from Tc-99m methylene diphosphonate (MDP) bone scan reports of Pediatric patients with suspected osteomyelitis

¹Jagrati Chaudhary, ¹Anil Kumar Pandey,¹ Shivam Arora, ²Vibhanshu Pandey, ³Param Dev Sharma, ⁴Ravi Mittal, ¹Rakesh Kumar

¹Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, ²Department of Information Technology, Maharaja Agrasen Institute of Technology, New Delhi, ³Department of Computer Sciences, SGTB Khalsa College, University of Delhi, New Delhi, ⁴Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi

Introduction

Early and accurate diagnosis of pediatric osteomyelitis is essential, yet the unstructured free-text format of Tc-99m MDP bone scan reports limits data integration and analysis. Large Language Models (LLMs) offer a potential solution by transforming these reports into structured data, thereby overcoming the constraints of traditional string-matching approaches. To mitigate data privacy concerns, we employed a locally deployed Meta’s LLaMA3.2:2b model, avoiding the risks associated with cloud-based services. Nevertheless, as a general-purpose model, Meta’s LLaMA3.2:2b may produce errors or hallucinations, and without domain-specific training on Tc-99m MDP bone scan reports of pediatric patients with suspected osteomyelitis, its reliability remains uncertain.

Aim

This study aimed to validate the performance of a locally deployed Meta’s LLaMA3.2:2b model for extracting structured data from unstructured Tc-99m MDP bone scan reports in children with suspected osteomyelitis.

Methods

This study used a locally deployed Llama3.2:2b model to extract information from 28 Tc-99m MDP bone scan reports for suspected pediatric osteomyelitis. A Python script with zero-shot prompting extracted data into 19 predefined fields on a Windows 10 PC with an Intel i7 CPU and an RTX 2060 GPU, with evaluation performed on the CPU. The model’s performance was measured using fuzzy string matching and Nuclear Medicine expert evaluation to calculate precision, recall, and F1-scores.

Results

While fuzzy string matching showed strong performance in structured fields (F1 ≥0.94) but poor results in clinical interpretation (F1 ≤0.60), semantic evaluation by a Nuclear Medicine expert maintained high accuracy in structured fields and substantially improved interpretation metrics—Dynamic Phases (F1 up to 0.92), Skeletal Distribution (0.30 vs. 0.06), and Certainty/Qualifier (1.0 vs. 0.0)—highlighting the model’s ability to extract semantically correct information despite wording variations. The model processed reports in an average of 29 seconds, approximately 18 times faster than a human expert.

Conclusion

The locally deployed Llama3.2:2b model accurately extracts straightforward information from pediatric bone scan reports. While automated metrics show lower performance on complex, interpretive content, human evaluation reveals a higher rate of semantic correctness, suggesting the model’s outputs are clinically useful but require validation. The model is also highly efficient, processing reports in just 29 seconds on average, 18 times faster than a human expert.

Funding Agency: This work was supported by the Indian Council of Medical Research (ICMR), Project Code: I-1810.

ABAOCNMB130: Evaluating the Clinical Utility of Locally Deployed Large Language Model for Ga-68 PSMA PET/CT Report Mining for Prostate cancer patients

¹Anil Kumar Pandey, ¹Jagrati Chaudhary, ²Param Dev Sharma, ³Sanjay Kumar, ⁴Haresh Kunhiparambath, ⁵Chandan J Das, ⁶Ranjit Sahoo, ⁷Seema Kaushal, ⁸M. Kalaivani, ¹Rakesh Kumar

¹Department of Nuclear Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, Indiam ²Department of Computer Science, SGTB Khalsa College, University of Delhi, New Delhi, India, ³Department of Urology, AIIMS, New Delhi, India, ⁴Department of Radiation Oncology, AIIMS, New Delhi, India, ⁵Department of Radiodiagnosis & Interventional Radiology, AIIMS, New Delhi, India, ⁶Department of Medical Oncology, AIIMS, New Delhi, India, ⁷Department of Pathology, AIIMS, New Delhi, India, ⁸Department of Biostatistics, AIIMS, New Delhi, India

Background

The immense volume of unstructured medical reports, such as those from Ga-68 PSMA PET/CT scans for prostate cancer, represents a significant hurdle for large-scale clinical research and effective patient management. While traditional data extraction methods are often limited by rigid, string-matching rules, Large Language Models (LLMs) present a novel solution by offering the ability to convert these reports into a structured, queryable format. However, using cloud-based LLMs raises substantial data privacy concerns, necessitating a secure, local processing approach.

Objective

This study evaluates the zero-shot performance of a locally deployed Meta’s LLaMA3.2:2b LLM in extracting diagnostic and staging information from Ga-68 PSMA PET/CT reports to assess its accuracy and clinical utility in a privacy-preserving environment.

Methods

To automate data extraction from 30 redacted Ga-68 PSMA PET/CT reports, we developed a Python script that uses zero-shot prompting to query a locally deployed LLM. The script asks 11 “yes” or “no” questions about key clinical staging features, including primary tumor, seminal vesicle invasion, lymph node status, and metastases. The model’s performance was evaluated by comparing its answers to a manually created “ground truth” dataset. The system, a Windows 10 PC with an Intel i7 processor (8 cores/16 threads), 16 GB of RAM, and an NVIDIA RTX 2060 GPU with 6 GB of VRAM, was used to query the Llama3.2:2b model. The evaluation was performed on a CPU-based setup as the CUDA toolkit was not installed.

Results

The LLM-extracted data was compared against the human-annotated ground truth. The comparison revealed the model’s accuracy on each of the 11 questions, highlighting its strengths in identifying certain features and its limitations or tendencies for hallucination on others. The results quantify the reliability of a general-purpose, non-fine-tuned Meta’s LLaMA3.2:2b for this specific clinical task. The model achieved an average per-question processing time of 19.13 seconds, making it nearly 20 times faster than human evaluation (385.71 seconds). The model achieved 90–100% accuracy on six questions, 80–90% on two questions, and 70–80% on three questions.

Conclusion

Meta’s Llama3.2:2b, deployed locally, efficiently and privately extracts key staging features from Ga-68 PSMA PET/CT reports, demonstrating high zero-shot accuracy for tumor and metastasis detection but with moderate limitations in nodal assessment. The model processed reports up to 20 times faster than manual review, highlighting its potential for structuring unstructured medical data.

ABAOCNMB070: Indian origin PET-CT lung cancer dataset with pathology-defined subtypes and detailed open-source annotations for clinical and AI use cases

Parveen Kundu, Rajat Vashistha, Sandeep Kumar, Harmeet Singh

Rohtak Nuclear Medcare Imaging Therapy and Research Center, India

Introduction

Positron emission tomography (PET) combined with computed tomography (CT) using 18F-fludeoxyglucose (18F-FDG) has become central to the diagnosis and staging of non-small cell lung cancer (NSCLC) [1, 2]. NSCLC accounts for nearly 85% of all lung cancer cases and includes adenocarcinoma (ADC), squamous cell carcinoma (SCC), large cell carcinoma, and mixed histotypes [2, 3]. Among these, ADC and SCC differ significantly at pathological, molecular, and clinical levels, necessitating distinct therapeutic strategies. However, most existing annotated datasets only provide tumor contours, lacking comprehensive regional annotations needed for staging and prognosis [4].

Methods

We developed a clinically validated PET-CT dataset of 54 patients with biopsy-confirmed NSCLC, including 26 cases of ADC and 28 cases of SCC. Tumor and region-of-interest (ROI) segmentation was conducted by an experienced nuclear medicine physician with over 12 years of clinical expertise, using ITK-SNAP (version 3.6). Seven ROIs delineated for each patient: lung lesion, mediastinal lymph nodes, supraclavicular lymph nodes (SCLN), normal tissue, liver tissue, bone, and brain [5].

Results

This dataset integrates imaging data with curated clinical metadata, including patient demographics, treatment history, AJCC staging, and overall survival. Comprehensive multi-region annotations provide more complete information for staging and metastasis assessment than currently available public datasets. Ethical approval for the study was obtained from the institutional review board.

Conclusion

By bridging the gap between imaging features and clinically relevant outcomes, this dataset supports both translational research and future integration of AI tools into routine lung cancer management in India.

ABAOCNMB097: Quantitative analysis in (xSPECT) and its comparison with conventional SPECT: A Technologist’s Perspective

KISHORE KUMAR, DINESH KUMAR

APOLLO HOSPITALS

Introduction

Single photon emission computed tomography fused with computed tomography (SPECT-CT) is a three-dimensional hybrid imaging used in nuclear medicine to image various organs. Despite its widespread use, conventional SPECT is limited by relatively low spatial resolution and lack of quantification. xSPECT, an advanced reconstruction algorithm incorporating CT-based attenuation correction, resolution recovery, and iterative reconstruction, offers enhanced image contrast, improved lesion delineation, better anatomical correlation and quantification. For nuclear medicine technologists, understanding the added clinical value of xSPECT is important for optimizing imaging protocols and ensuring accurate interpretation.

Aim

This study aims to assess the clinical value of xSPECT compared with conventional SPECT, with emphasis on improvements in image quality, lesion detectability, diagnostic confidence and workflow relevance from a technologist’s perspective.

Materials and Methods

This prospective observational study was conducted on 15 patients referred for bone scintigraphy using a Siemens Symbia Intevo SPECT-CT hybrid system. Following standard acquisition, both conventional Flash 3D and xSPECT-CT reconstructions were performed. Imaging parameters included a 15% energy window centered at 140 keV with a 15% scatter window, 256 × 256 matrix, and 18-second projections over 360° using continuous non-circular orbit. Plain CT was acquired as part of the protocol and was used for the CT-based attenuation correction in xSPECT and conventional SPECT. xSPECT bone reconstructions were performed with 24 iterations and 2 subsets, with integrated smoothing. Sequential interpretation of SPECT-CT and xSPECT-CT datasets were performed. Differences in lesion detection, delineation, and anatomical localization between the two reconstruction methods were documented and analyzed.

Results

The scan acquisition time for single bed in xSPECT and conventional SPECT was found to be same. In this series of musculoskeletal cases, xSPECT consistently demonstrated superior image resolution, enhanced lesion delineation, and greater diagnostic confidence compared with conventional SPECT by 70%. The technology improved visualization of small osseous lesions and allowed clearer differentiation between benign degenerative changes and malignant pathology. Furthermore, xSPECT facilitated more precise localization and quantification, thereby supporting improved clinical decision-making. In 12/15 the xSPECT/CT revised diagnosis was confirmed.

Conclusion

The study demonstrates that xSPECT is superior to conventional SPECT by enhancing image quality and underscores the importance of optimized acquisition and reconstruction protocols to maximize diagnostic yield from a technologist’s perspective.

ABAOCNMB104: Characterisation of Accumulated Long-Lived Radionuclides in Cyclotron Target Foils and Recovered [¹⁸O]H₂O Using a Cadmium Zinc Telluride (CZT) Detector

Dilshad Kottuparamban^1,2, Praveen Joseph³, Arunima Dev T V⁴, Midhun C V⁵, Muhammed Anees K¹, M M Musthafa⁴, M R Ambikalmajan Pillai¹

¹Molecular Cyclotrons Private Limited, Puthuvype, Ernakulam, Kerala, India, ²Department of Physics, Newman College, Thodupuzha, Idukki, Kerala, India, ³Department of Physics, St. Joseph’s College (Autonomous), Moolamattom, Idukki, Kerala, India, ⁴Department of Physics, University of Calicut, Malappuram, Kerala, India, ⁵Gamma Driven Experiments Department, ELI-NP, Magurele, Ilfov, Romania

Introduction

The ¹⁸O(p,n)¹⁸F reaction on enriched [¹⁸O]H₂O is the most widely adopted method for ¹⁸F production due to its high cross-section, carrier-free yield, and compatibility with medical cyclotron energies. Targets use an entrance foil, typically HAVAR, a cobalt-based alloy, in front of the [¹⁸O]H₂O loading cavity. Repeated proton bombardment activates this foil and generates long-lived radionuclides, which may leach into the target water. These nuclides complicate [¹⁸O]H₂O recycling, waste handling, and decommissioning of the facility. Gamma spectrometry enables direct identification and quantification of these radionuclides, especially with a semiconductor detector. The Cadmium zinc telluride (CZT) detector, operating at room temperature with moderate resolution, offer a practical alternative to NaI(Tl) which lacks resolution and HPGe which has high resolution but costly and cryogenically demanding. This study evaluates the feasibility of CZT detectors for identifying and assessing long-lived radionuclides in the HAVAR foil and recovered [¹⁸O]H₂O.

Materials and Methods

Gamma spectra of irradiated HAVAR foils and [¹⁸O]H₂O were acquired using a laboratory-grade CZT detector (<2.5% FWHM at 662 keV). Measurements were made after long decay to improve statistics and reduce occupational exposure. Standard reference sources covering a wide energy range used for energy and efficiency calibrations, and data were processed using multichannel analysis software. Radionuclide identification was performed by matching observed gamma peaks with nuclear data from IAEA and ENSDF libraries. Wherever possible, relative intensities were compared to confirm isotopic assignments and support quantification.

Results

The CZT detector resolved multiple activation peaks in the samples including Co-57 (122 keV), Mn-54 (834 keV), and Co-60 (1173 and 1332 keV). Quantification enabled decay-period prediction, essential for safe storage, regulatory clearance, and planning of waste disposal and decommissioning. Detection of cobalt and manganese in water confirmed leaching from foils, linking foil activation to radionuclidic impurities in [¹⁸O]H₂O and impacting recycling efficiency. These findings show that CZT detectors can provide both qualitative identification and quantitative insight into activation build-up in cyclotron facilities.

Conclusion

This study presents an initial demonstration of CZT spectrometry for characterizing long-lived radionuclides in irradiated [¹⁸O]H₂O and HAVAR foils. Its compact, cryogen-free design makes it well suited for medical cyclotron facilities. This protocol provides actionable intelligence for enriched water purification, radiation safety in target maintenance, and strategic waste management. Collectively, these outcomes support a more reliable, sustainable, and globally applicable framework for PET radionuclide production and facility lifecycle management.

ABAOCNMB142: Impact of Reconstruction Parameters on Image Quality and Quantitative Accuracy in PET/CT Imaging Systems: A Phantom Study

Jay Prakash Kumar ^1,2, Manoj Chauhan^1,2, Arvind Suresh^1,2, Ritwik Sinha ^1,2, Uddeshya Narayan^1,2, Swayamjeet Satapathy ^1,2

¹Dept. Of Nuclear Medicine, Mahamana Pandit Madan Mohan Malaviya Cancer Centre &Homi Bhabha Cancer Hospital (A unit of Tata Memorial Centre), Varanasi, ²Homi Bhabha National Institute, Mumbai, Maharashtra, India

Introduction

PET/CT is multimodal imaging techniques that provide both functional and anatomical information. The most widely used algorithm for PET image reconstruction is Ordered Subset Expectation Maximization (OSEM). In OSEM, the image noise increases with increased number of iterations, requiring the reconstruction process to be stopped before full convergence is achieved to prevent excessive noise. To overcome this challenge, the Bayesian Penalized Likelihood (BPL) reconstruction algorithm has been introduced. BPL incorporates a regularization parameter (β) that imposes a noise penalty, allowing the reconstruction to reach full convergence while effectively suppressing image noise.

The objective of this study is to evaluate the impact of reconstruction algorithms and lesion radioactivity levels on PET image quality and quantitative accuracy across PET systems.

Material and Method

The NEMA IQ phantom was filled with [¹⁸F] FDG at a sphere-to-background activity concentration ratio of 4:1 and scanned on the GE Discovery IQ PET/CT system. PET images were reconstructed with OSEM or BPL algorithm. The number of iterations and β-values were varied across reconstructions, while the matrix size, number of subsets, and filter Cutoffs were kept constant. After reconstruction, the images were evaluated and compared using the NEMA analysis tools available for each system, using automatic localisation of the region-of-interests (ROI). Contrast recovery (CR) and background variability (BV) values were determined for each ROI in all reconstructed PET images to assess the image quality and quantification accuracy.

Result

Contrast recovery (CR) increased with increased sphere size from 10 mm to 22 mm in diameter. Contrast recovery (CR) and background variability (BV) decreased gradually in reconstructed images with increased β-values. Increased number of iterations in OSEM showed increased BV and CR.

BPL gave higher CR and lower BV values than OSEM. The Bayesian Penalized Likelihood (BPL) reconstruction with β-values in the range of 150 to 350 was identified as optimal.

Conclusion

PET images acquired on GE Discovery IQ PET/CT and reconstructed with the Q-clear algorithm provided the best image quality and quantitative accuracy for the smallest sphere

ABAOCNMB123: SiPM and CsI based miniature radiation detectors for use in Automated Radiochemistry modules

Yuva Raj Nitin, Nawab Singh Baghel

Radiation Medicine Centre, Bhabha Atomic Research Centre, Tata Memorial Hospital Annex Building, Parel Mumbai

Introduction

The integration of compact, reliable, and sensitive radiation detectors within automated radiochemistry modules is critical for real-time process monitoring, synthesis optimization, and quality control in the production of radiopharmaceuticals. This paper details the design and development of a miniature, solid-state radiation detector based on a Silicon Photomultiplier (SiPM) coupled with a CsI(Tl) scintillator, specifically engineered for embedded applications in confined spaces of automated synthesis units.

Materials and Methods

a) Hardware and software: The detector core consists of a small, ruggedized CsI(Tl) scintillation crystal selected for its high light yield and compatibility with the SiPM’s sensitivity spectrum. The SiPM replaces traditional photomultiplier tubes and Geiger counters, offering significant advantages in size and bias voltage requirements. A low-noise, custom-designed analog front-end circuit amplifies and shapes the SiPM output signal. This signal is processed by an on-board microcontroller for pulse counting and data analysis.

b) Method: The microcontroller implements algorithms for real-time activity measurement and communication. The detector is designed to interface directly with the radiochemistry module’s control system via a digital UART or I2C interface, providing continuous readout of activity levels within reaction vials or transfer lines.

Results

Prototype detectors were characterized and demonstrated high sensitivity, excellent pulse resolution, and stable performance under continuous operation. The miniature design was successfully integrated into a test setup, providing reliable real-time data for synthesizer process control.

Conclusion

This SiPM-based miniature detector presents a robust, compact, and highly effective solution for in-line radiation monitoring, enhancing the automation, efficiency, and reliability of radiochemistry modules in a nuclear medicine facility.

ABAOCNMB122: Design of Ethernet connected Scintillation Detector for Stack Monitoring in Medical Cyclotron Facility

Yuva Raj Nitin¹, Kamaldeep², Nawab Singh Baghel¹

¹Radiation Medicine Centre, Bhabha Atomic Research Centre, Tata Memorial Hospital Annex Building, Parel Mumbai, INDIA 400012, ² Health Physics Division, BARC

Introduction

The safe operation of a medical cyclotron facility necessitates rigorous and continuous monitoring of airborne radioactive emissions, particularly from stack discharge points, to ensure regulatory compliance and protect public health. This paper presents the design and implementation of a robust, Ethernet-connected scintillation detector system specifically tailored for real-time stack monitoring.

Materials and Methods

a) Hardware and software: The system utilizes a high-sensitivity inorganic scintillator coupled with a photomultiplier tube (PMT) to achieve high-efficiency detection of gamma-ray emissions from radionuclides commonly produced in cyclotron operations, such as F-18, C-11, and O-15. The analogue signals from the PMT are processed by a dedicated nuclear instrumentation chain, including a high-voltage power supply, preamplifier, amplifier, and a single-channel analyser (SCA), before being digitized.

b) Method: A central innovation of this design is the integration of a microcontroller with an embedded Ethernet controller. This allows the processed radiation data (counts per second or dose rate) to be packetized and transmitted over a standard Local Area Network (LAN) via TCP/IP protocol. This Ethernet connectivity enables remote, real-time data acquisition, system configuration, and status monitoring from a centralized control room or a secure web interface. The design emphasizes reliability, remote diagnostics, and failsafe operation, incorporating features for high-voltage control, gain stabilization, and automated alarm triggering upon detection of activity exceeding pre-defined thresholds.

Results

The system was calibrated using known gamma sources and demonstrated excellent linearity, sensitivity, and stability for effective stack monitoring.

Conclusion

This networked detector provides a modern, scalable, and cost-effective solution for enhancing the radiation safety infrastructure of medical cyclotron facilities.

ABAOCNMB230: Establishment of Institutional Diagnostic Reference Levels for the Computed Tomography Component of ^99mTc-Tropane Derivative Dopamine Transporter-1 Single Photon Emission Computed Tomography/Computed Tomography Brain Imaging

Muppidi Abhishek Mano, K K Kamaleshwaran, Ram Kumar E, Radhakrishnan E R, Kingsley F R, Arun Pandiyan, Aadhavan P, Jeba Getzi, Kowsalya R, Manoaj M

Nuclear Medicine Department, Kovai Medical Centre and Hospital, Coimbatore, India.

Introduction, Aims

Combined Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) imaging together is well-practiced in Neuroimaging. While the radiopharmaceutical itself provides a radiation dose, the CT portion of the image, used more for attenuation correction and anatomical localization, also contributes to the total combined radiation dose to the patient. A powerful tool for dose optimization, helpful to ensure doses are As Low As Reasonably Achievable(ALARA), is local Diagnostic Reference Levels (DRLs). DRLs are defined as The radiation dose level at or below which 75% of imaging facilities operate for a specific procedure. The goal of this study was to establish institutional DRLs for the CT portion of our adult ^99mTc-TRODAT-1(Tropane Derivative Dopamine Transporter) brain SPECT/CT exams based on Volume Computed Tomography Dose Index (CTDI_vol) and Dose Length Product (DLP).

Materials and Methods

Data was retrospectively reviewed from 22 adult patients who underwent 99mTc-TRODAT-1 SPECT/CT scans between July 23, 2025, and October 8, 2025. CTDI_vol and DLP values were extracted from scanner-generated dose reports, which were then uploaded to PACS, for diagnostic quality scans performed on SPECT/CT scanner. Summary statistics (mean, median) for CTDI_vol and DLP were calculated, defining institutional DRLs as the 75^th percentile of these dose distributions.

Results

The mean CTDI_vol was 11.67mGy and the median CTDI_vol was 11.70mGy. The mean DLP was 224.23 mGy·cm and the median DLP was 220.50 mGy·cm. From this data, the calculated 75th percentile for CTDI_vol was 12.0 mGy, and for DLP, the calculated 75th percentile was 232.75 mGy·cm.

Conclusion

This study represents the first institution-specific DRLs for the CT component of 99mTc-TRODAT-1 SPECT/CT studies at our institution, with suggested DRLs of 12.0 mGy for CTDIvol and 232.75 mGy·cm for DLP. By comparing these DRLs with median dose values calculated every six months for specific CT protocols, institutions can effectively monitor and optimize radiation doses. This methodology can also be applied to calculate DRLs for other institutional procedures, thereby promoting patient safety and adherence to the ALARA principle.

ABAOCNMB235: Institutional experience of CT Dose optimisation in PET/CT: Utilizing Dose Reports to identify targets for radiation dose Optimization

Asfaq Ahmed S., Dr Uma Ravishankar, Dr Kanika Kakkar, Vikrama Pandian, Dr Shefali Kalra

Indraprastha Apollo

Introduction and Aim

Radiation exposure refers to the amount of ionizing radiation absorbed by an individual. Sources of radiation exposure in medical imaging include diagnostic X-rays (including dental X-rays), CT scans, nuclear medicine procedures, and interventional radiology. The radiation dose with CT imaging is of considerable concern because it gives the highest exposure. The CT component contributes significantly to the total radiation dose in PET/CT scan, making radiation exposure dose monitoring essential. Automated CT dose reports from acquisition software provides critical data for this purpose. The aim of this study is to analyse CT dose parameters (CTDIvol, DLP, mAs) from clinical PET/CT studies and to identify specific targets for future protocol optimization.

Materials and Methods

An observational study. Total no. of subjects - 50. All studies were performed on Siemens Biograph mCT128-slice PET-CT. A PET-CT scan from the vertex through the mid‐thigh (till toes only if clinically indicated) in 90 sec bed positions (3D mode). Low‐dose NCCT (120kVp, 20-180 mAs, which is automatically calculated by an in built software CARE Dose4D) would permit attenuation correction, followed by PET reconstruction via ordered‐subsets expectation–maximization. A contrast enhanced CT was performed when clinically indicated. DLP was calculated by the inbuilt acquisition software. DLP was then converted to standard radiation exposure unit (mSv). A detailed analysis of the data on radiation dose received by the patients was done.

Results

Analysis of the ranked data revealed a distinct subset of patients receiving a higher radiation dose. Out of 50 patients, 10 patients received a mean CTDIvol of 15.5 mGy, slightly more than national DRL of 11.0 mGy, which is mainly attributed to various CT protocols which increase the radiation dose. The remaining 40 patients received doses at or below the national DRL.

Conclusion

This study confirms that our standard PET/CT protocol is appropriate for the majority of patients. However, it clearly identifies certain patient groups for optimization of CT dose, and modifying radiopharmaceutical injection dose when a higher CT dose is expected. The systematic use of dose reports has provided a data-driven justification for implementing modified CT protocols, decreasing number of delayed CT scans and radiopharmaceutical dose to reduce radiation exposure, thereby enhancing overall patient safety without compromising image quality. This study will bring the consciousness and insight of optimising CT dose delivered during PET CT scans and reduce total radiation burden on patients, especially in settings where repeated follow up scans are required.

ABAOCNMB271: Preparation of patient doses of [177Lu] Lu-DOTATATE and [177Lu] Lu PSMA-617 with the addition of a carrier added (CA) and with no carrier added (NCA).

Srikanth Saminathan, Arvind Suresh, Ravi Kumar Chauhan

Mahamana Pt. Madan Mohan Malviya Cancer Centre, BHU & Homi Bhabha Cancer Hospital, Varanasi 221005, UP, India

Introduction, Aims

Peptide Receptor Radionuclide Therapy utilizing Lu¹⁷⁷-DOTATATE for (NeuroEndocrine Tumors (NET) and Lu¹⁷⁷-PSMA-617 for metastatic castration-resistant prostate cancer has become a pivotal treatment modality. The preparation parameters are contingent upon the specific activity of the Lu¹⁷⁷Cl. The quality of the resulting radiopharmaceutical, particularly its specific activity, is intrinsically linked to the choice of the Lu¹⁷⁷ source: Carrier Added (CA) or No Carrier Added (NCA). This study aims to meticulously compare the synthesis protocols, radiochemical efficiency, and quality control parameters required for preparing patient-ready doses of both Lu¹⁷⁷-DOTATATE and Lu¹⁷⁷-PSMA-617 using both CA-Lu¹⁷⁷Cl and NCA-Lu¹⁷⁷-Cl.

Method

All preparations were conducted in compliance with Good Manufacturing Practice (GMP) guidelines using commercially available cold peptide precursors (DOTATATE and PSMA-617). The radiolabelling of DOTATATE and PSMA-617 was performed using Lu¹⁷⁷-(CA and NCA). The parameters analysed include Lu¹⁷⁷ with differing specific activities, various peptide concentrations, and two unique buffer systems. To evaluate the radiochemical yield and purity, paper and thin-layer chromatography systems were utilized. The purification of the labelled tracers was carried out using solid-phase extraction. Radiochemical Purity was immediately assessed post-synthesis using ITLC (Instant thin-layer chromatography) with suitable mobile phases to quantify free Lu¹⁷⁷ and colloidal Lu¹⁷⁷ impurities.

Results

Lu¹⁷⁷-DOTATATE was synthesized using CA Lu¹⁷⁷ (n = 15) and NCA Lu¹⁷⁷ (n = 8). Six batches of Lu¹⁷⁷-PSMA-617 were produced utilizing both CA and NCA Lu¹⁷⁷. All batches achieved radiochemical yields exceeding 90%, and the final product contained less than 3% radiochemical impurity, making them suitable for therapeutic use. A significant finding was the difference in specific activity; NCA-Lu¹⁷⁷ preparations demonstrated an approximately higher specific activity (p< 0.001) compared to the CA preparations for the same final therapeutic activity.

Conclusion

Comprehensive protocols for the formulation of clinical doses of Lu¹⁷⁷-DOTATATE and Lu¹⁷⁷-PSMA-617 have been established and utilized for the preparation of clinical doses. The quality of the SPECT images for both tracers aligns with the anticipated uptake in their respective diseases.

ABAOCNMB220: Optimizing the capacity of the delay tank to safely dispose of the excreta of I-131 patients in a two-bed radioiodine therapy ward

S V Ramana Murthy, K B Sricharan Charan, K J U Sekhar, K Raja Kumar, Sanjay Kumar

Homibhabha Cancer Hospital & Research Centre, Under Dept of Atomic Energy

Introduction

Radioiodine (I-131) therapy is widely used for the treatment of thyroid cancer, with patients excreting nearly 80% of the administered dose through urine and feces. Safe disposal of this radioactive waste is essential to comply with Atomic Energy Regulatory Board (AERB), India guidelines and to minimize environmental risks.

Aim

The present study aims to optimize the design and capacity of the delay tank system in a two bedded radioiodine therapy ward to ensure safe disposal of I-131 excreta within regulatory limits.

Method

Our department admits four iodine patients every week, and the maximum amount of activity that each patient can receive is 125mCi of I-131, of which nearly 80% is excreted. The total activity, tank capacity, and tank count are computed for various collecting periods (7, 14, 21,28,35,42,49,56,60 days).

Results

The decay tank’s accumulated activity after 60 days (the ideal collection duration) is 337mCi and applying a 60-day decay factor (0.0052), the final retained activity is 1.75mCi in 7200Litres of waste water, corresponding concentration is 0.23µCi/L which is within the AERB prescribed limit (less than 0.6µCi/L). It is done with each delay tank with a capacity of 7500 Litre to reach the discharge concentration activity 0.23 µCi /L which is within the AERB prescribed limit (less than 0.6 µCi /L).

Even with higher procurement activity (600mCi/week; 150mCi per patient), the final effluent concentration is 0.29µCi /While at lower procurement levels (400mCi/week) it is 0.19µCi/L both remaining below regulatory thresholds. If the delay tank capacity is only 6000 litres and you are holding waste for three months (90days) before discharge, the limits the patient throughput because the tanks fills up faster with each patient’s excreta (especially at 125-150mCi per therapy). You must wait for sufficient decay time to ensure discharge concentration is below AERB prescribed limit (less than 0.6 µCi /L).

The study further shows that increasing the delay tank capacity from 6000 litres to 7500litres enhances safety margins.

Conclusion

Increasing the delay tank capacity from 6000 litres to 7500 litres provides an effective and safe strategy for handling I-131 excreta in a two bedded radioiodine therapy ward facility. This approach ensures compliance with radiation safety standards, increased operational efficiency in higher patient throughput and shorter turnaround times for storage.

ABAOCNMB186: TO OPTIMISE IN HOUSE LABELLING OF 68GA TRIVEOCTIN AND QUALITY CONTROL

Ajay Kumar, Manoj Kumar Chauhan, Arvind Suresh, Yash Jain, Srikanth Swaminathan, Jayprakash Kumar, Ritwik Sinha, Uddeshya Narayan Jha, Ravi Kumar Chauhan, Bhola Kumar, Arvind Gupta

Mahamana Pandit Madanmohan Malaviya Cancer Centre (A unit of Tata Memorial Centre)

Introduction

Glioblastoma multiforme (GBM) is the most common form of primary malignant brain tumour. Glioblastomas arise from glial cells, which normally help support and nourish nerve cells of the brain (neurons) and form scar tissue that helps repair brain damage in response to injury. Glioblastoma are often very aggressive and grow into surrounding brain tissue. The tumours also are comprised of the body’s own white blood cells that arise from the bone marrow. ⁶⁸Ga labelled Triveoctin is future radiopharmaceutical for evaluation the uptake of nerve cells in brain tumour. The in house preparation and quality control of same was done.

Aim

To optimise the in house labelling of ⁶⁸Ga Triveoctin using automated Gallium synthesizer and to find out RCP (radiochemical purity) using iTLC (instant Thin Layer Chromatography)

Material and Methods

⁶⁸Ga Triveoctin was prepared by using automated Gallium synthesizer (iQS-TS). Triveoctin (50µg) peptide was procured from Germany (Lichtenbergstrasse). Buffer solution 0.02255g Sodium acetate in 1.1mL water was added to the vial of Triveoctin peptide. Mixture was mixed well and transferred to reaction vial. The ⁶⁸Ga was eluted by using 0.05M HCl and labelling takes place in reaction vial by heating. C18 cartridge was initially rinsed with 70% Ethanol followed by 0.09% normal saline. The product from reaction vial was passed through C18 cartridge. The unlabelled product was collected in waste vial and desired labelled product was collected in product vial. The quality control of final product was done by iTLC (instant Thin Layer Chromatography) using sodium citrate as a solvent.

Result

The RCP (radiochemical purity) of final product of ⁶⁸Ga Triveoctin was found approx. 97%.

Conclusion

⁶⁸Ga Triveoctin is promising radiopharmaceutical for imaging of Glioblastoma multiforme (GBM) patients for evaluation the uptake of nerve cells in brain tumour.

ABAOCNMB271: Preparation of patient doses of [177Lu] Lu-DOTATATE and [177Lu] Lu PSMA-617 with the addition of a carrier added (CA) and with no carrier added (NCA).

Srikanth Saminathan, Arvind Suresh, Ravi Kumar Chauhan, Ajay Kumar

¹Mahaman Pt. Madan Mohan Malviya Cancer Centre BHU and Homi Bhabha Cancer Hospital, Varanasi 221005, UP, India(A unit of Tata memorial centre), ²Homi Bhabha National Institute Mumbai

Purpose

[177Lu] Lu-DOTATATE and [177Lu] Lu-PSMA-617, utilized in targeted radionuclide therapy (PRRT), are often prepared in the radio pharmacy of hospitals. The preparation parameters are contingent upon the specific activity of the 177Lu that is used. This study’s goal was to develop optimized protocols for the preparation of patient doses of these radiopharmaceuticals in the nuclear medicine department.

Method

The radiolabelling of DOTATATE and PSMA-617 was performed using 177Lu (CA and NCA). The parameters analysed include 177Lu with differing specific activities, various peptide concentrations, and two unique buffer systems. To evaluate the radiochemical yield and purity, paper and thin-layer chromatography systems were utilized. The purification of the labelled tracers was carried out using solid-phase extraction.

Results

[177Lu] Lu-DOTATATE was synthesized using CA 177Lu (n = 15) and NCA177Lu (n = 8). Six batches of [177Lu] Lu-PSMA-617 were produced utilizing both CA and NCA 177Lu. All batches achieved radiochemical yields exceeding 89%, and the final product contained less than 3% radiochemical impurity, making them suitable for therapeutic use.

Conclusion

Comprehensive protocols for the formulation of clinical doses of [177Lu] Lu-DOTATATE and [177Lu] Lu-PSMA-617 have been established and utilized for the preparation of clinical doses. The quality of the SPECT images for both tracers aligns with the anticipated uptake in their respective diseases.

ABAOCNMB120: Preparation of Radiolabeled Tracer for Bovine Progesterone Assays

Krishna Mohan Repaka^1*, Chandrakala Gholve², Sapana Donadkar², Yogita Pawar², Smita Gawandi², Nawab Singh Baghel²

¹MCF, RMC, BRIT, C/O TMH Annexe, Parel, Mumbai-400 012, ²Radiation Medicine Centre, BARC, C/O TMH Annexe, Parel, Mumbai-400 012

Background

Progesterone is vital steroid hormone regulating the menstrual cycle, implantation, and pregnancy maintenance. Its accurate quantification is essential for evaluating luteal phase sufficiency, infertility, early pregnancy risk, and monitoring hormone therapy. While traditional tritiated (³H) tracers were widely used in radioimmunoassays (RIA), they are limited by poor stability and low counting efficiency. To overcome these drawbacks, iodinated (¹²⁵I) derivatives of progesterone have been explored, offering improved sensitivity, stability, and reproducibility. Recent studies have demonstrated the successful development of in-house ¹²⁵I-histamine progesterone tracers with high radiochemical purity, strong specific binding, and prolonged stability under refrigeration [1]. Similar approaches have also been applied to milk progesterone measurement, highlighting their versatility in clinical and veterinary endocrinology [2].

Aim

To develop and purify ¹²⁵I-labeled progesterone derivatives with high radiochemical stability and specificity for use as tracers in progesterone RIAs.

Materials and Methods

Progesterone-11α-hemi succinate, Na¹²⁵I, histamine, Chloramine-T, Sodium metabisulfite, NaOH, Dioxane, Toluene, phosphate buffers, rabbit polyclonal antisera raised against progesterone–BSA conjugates. The synthesis steps included: (i) preparation of progesterone mixed anhydride in dry dioxane at 4 °C, (ii) iodination of histamine with ¹²⁵I using the chloramine-T method, (iii) coupling of iodinated histamine to progesterone mixed anhydride, and (iv) purification by solvent extraction, thin-layer chromatography, and column chromatography. Radiochemical purity and specific activity were assessed, and immunoreactivity tested using binding assays with progesterone antisera.

Results

Fractions with the highest radioactive counts showed specific binding (%B/T) up to 24% with progesterone antisera, confirming immunological activity. Non-specific binding (%NSB) accounted around 7.5% of total binding, which is acceptable for steroid hormone RIAs. These findings are consistent with recent reports of in-house ¹²⁵I-progesterone tracers achieving high purity, specific binding above 40%, NSB below 5%, and stability for over 12 weeks [1,2].

Conclusion

The iodinated progesterone derivatives developed in this study demonstrated adequate radiochemical stability and retained significant immunoreactivity. Although specific binding values were moderate, optimization of iodination and purification could further enhance performance. Compared with older tritiated tracers, ¹²⁵I-derivatives offer superior stability and reproducibility, supporting their application in clinical and research RIAs.

ABAOCNMB058: Optimization of in house Radiosynthesis of non-carrier added ¹⁷⁷Lu-FAP-2286 in a Hospital-Based Radio-pharmacy by its radiochemical purity and In-vitro stability evaluation.

Mr. ManojKumar Hariram Chauhan^1,3 Mr. Dibya Prakash ^1,3, Mr. Vishal Vajarkar ^1,3, Mrs. Sarika Paunikar^1,3, Mrs. Kranti Khairnar^1,3, Archi Agarwal ^1,2,3,

¹Department of Nuclear Medicine and Molecular Imaging, Advanced, Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Navi Mumbai, India, ²Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India, ³Homi Bhabha National Institute, Mumbai, India.

Introduction

Fibroblast activation protein (FAP) is highly expressed on cancer-associated fibroblasts within the tumor microenvironment, with minimal expression in normal tissues, making it a promising target for radiopharmaceutical therapy. ¹⁷⁷Lu-FAP-2286, a radiolabeled peptide, is utilized for treating advanced or metastatic solid tumors expressing FAP. Objective of the study is to optimize the in-house radio-synthesis of non-carrier-added (n.c.a.) ¹⁷⁷Lu-FAP-2286 in a hospital-based radio-pharmacy and to evaluate its radiochemical purity and stability.

Materials and Methods

Radio-synthesis of n.c.a. ¹⁷⁷Lu-FAP-2286 was performed using ¹⁷⁷LuCl3 (ITG, Germany) in a controlled hospital radiopharmacy environment. FAP-2286 peptide (1mg), sodium ascorbate and ascorbic acid were obtained from B.J. Madan & Co. (India).

A stock buffer solution (pH 4.5) was prepared by dissolving sodium ascorbate and ascorbic acid in HPLC-grade water in a 15 mL sterile conical tube. An aliquot of 100 µg FAP-2286 peptide (1 g :1 mL peptide-HPLC water) was combined with 900 µL of sodium ascorbate buffer in a sterile Eppendorf tube, then transferred to a reaction vial containing 200 mCi n.c.a. ¹⁷⁷LuCl3. The reaction vial was placed in a dry heating block and incubated at 95°C for 35 minutes. Post-reaction, the product was purified using a C-18 Sep-Pak cartridge, yielding a sterile radiopharmaceutical suitable for clinical administration.

The radiochemical purity was evaluated using instant thin-layer chromatography (ITLC) with ITLC-SG plates as the stationary phase and 0.1 M sodium citrate as the mobile phase, with an RCP acceptance criterion of ≥95%. In-vitro Stability was assessed over 15 days with samples stored at −20°C and samples at ambient temperature (19°C), by the mean of RCP measured at regular intervals.

Results

The radio-synthesis yield was high with high labelling efficiency of 99.95%. In Vitro Stability tests showed sample stored at -20°C had RCP of 98.65%, which is within the permissible limit for radionuclide therapy and remained stable for two weeks. In contrast, the sample stored at 19°C exhibited RCP below 95%, with degradation observed from day 7 onward.

Conclusion

The in-house radio-synthesis of n.c.a. ¹⁷⁷Lu-FAP-2286 demonstrated superior radio-labelling efficiency and high radiochemical purity. The product exhibited remarkable stability, maintaining its integrity even after 7 days at room temperature. Additionally, this stability can be maintained up to 15 days when stored at −20°C. This study highlights the feasibility of hospital-based radiosynthesis of ¹⁷⁷Lu-FAP-2286 and its extended potential clinical use.

ABAOCNMB110: Fully Automatic Synthesis of [18F]Flurpiridaz and Its Quality Control Analysis for Clinical Application

Anupriya Dev, Manish Dixit, Vaibhav Pandey, Md. Faheem

Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, UP, India

Background

[18F]Flurpiridaz is a promising novel cardiac PET tracer recently approved by the FDA for myocardial perfusion imaging (MPI). It provides improved image quality and diagnostic accuracy compared with conventional radiotracers. The present study focused on developing a fully automated synthesis protocol for [¹⁸F]Flurpiridaz using the MPS-200 automated system, along with a comprehensive quality control (QC) evaluation to ensure compliance with regulatory guidelines for clinical application.

Materials and Methods

The radiolabelling was performed on a Sumitomo automated multipurpose synthesizer MPS-100 using conventional 18F-chemistry for converting precursor into desired [18F]Flurpiridaz in one step. The crude product was purified on a pre-conditioned SepPak C18 Plus cartridge, washed with sterile water to remove unreacted [¹⁸F]Fluoride, and eluted with 1 mL ethanol and further diluted with saline. QC analyses were performed as per standard protocols such as high-performance liquid chromatography (HPLC), iTLC, Ph and others.

Results

The fully automated synthesis protocol produced [18F]Flurpiridaz with good radiochemical yield in the range 65–70% (decay-corrected). HPLC analysis confirmed radiochemical purity > 98%. The final product remained stable for up to 12 hours post-synthesis.

Conclusion

A fully automated synthesis method for [18F]Flurpiridaz was successfully established using the MPS-200 in a single step synthesis approach. Optimization of the automated process achieved high radiolabelling yield and purity. The final product demonstrated excellent stability and met all acceptance criteria, supporting its safe clinical application in myocardial perfusion PET imaging.

ABAOCNMB046: DEVELOPMENT OF AN AMBIENT TEMPERATURE STABLE FREEZE-DRIED HYNIC TOC KIT: TOWARDS A MORE AFFORDABLE DIAGNOSIS FOR NEUROENDOCRINE TUMORS

Satyajit Mohanty^1,2, Kusum Vats^1,2, Madhava B Mallia^1,2

¹Homi Bhabha National Institute, Anushaktinagar, Mumbai - 400094, India, ²Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai - 400085

Introduction

^99mTc-Hynic TOC is a well known radiopharmaceutical for diagnostic imaging of neuroendocrine tumours (NETs). In the last decade, indigenous availability of freeze-dried Hynic TOC kits had given a significant boost to NET therapy using ¹⁷⁷Lu-DOTATATE. Despite the availability of PET radiopharmaceuticals, ^99mTc-Hynic TOC is used in several nuclear medicine centres across the country. In this context, any efforts towards further reduction in cost of the freeze-dried kit will only boost the clinical use of ^99mTc-Hynic TOC. At present, a significant cost of the kit is attributed to the use of dry ice during its transport. Present work aims to develop a kit which can be transported and stored at ambient temperature.

Aim

To develop a freeze-dried Hynic TOC kit that could be stored and transported at ambient temperature.

Materials and Methods

In-house synthesized Hynic TOC peptide was used for the preparation of freeze-dried kits. All the chemicals used for kit preparation were purchased from reputed suppliers. To finalize the kit formula with mannitol, wet radiolabeling was carried out. Since the kit formula without mannitol is known (Hynic TOC - 40 ug, EDDA - 10 mg, Tricine - 20 mg, SnCl₂ - 40 ug, NaH₂PO₄.2H₂O - 28 mg, Na₂HPO₄.2H₂O - 4.3 mg) the same amount of kit components along with 10, 25 and 50 mg of mannitol was used for radiolabelling with technichium-99m. Subsequently, a 10 vial batch of freeze-dried kits with 25 mg of mannitol was prepared following well established protocol. The vials were stored at ambient temperature and tested at different time intervals (2 days, 1 week, 10 days, 2 weeks, etc.) to check the stability of the formulation. To prepare ^99mTc-Hynic TOC, about 1 mL of freshly eluted technetium-99m was aseptically transferred to the kit vial. The vial was gently shaken to dissolve the contents and then incubated in boiling water bath for 30 min. After cooling the reaction mixture to ambient temperature, the radiochemical purity (RCP) was analyzed by HPLC.

Results

It was observed that the amount of mannitol has no effect on radiolabeling. More than 90% RCP was achieved with different amounts of mannitol tested. The physical appearance of the kits remained unchanged and ^99mTc-Hynic TOC with >90% RCP was observed even after two weeks of storage at ambient temperature.

Conclusion

At present, the kits are undergoing limited clinical evaluation. This work is a significant step towards making NET diagnosis more affordable.

ABAOCNMB226: Influence of Glycemia on Liver Uptake of 18F-FDG(18F-fluorodeoxyglucose) in PET/CT Imaging.

N Sasirekha, Anjana S S, Dhanapathi Halanaik

Jawaharlal Institute of Postgraduate Medical Education and Research

Introduction

Positron emission tomography/computed tomography (PET/CT) is an imaging modality used for diagnosis, staging, and therapeutic response assessment in oncology. Radiolabeled [18F]fluorodeoxyglucose (18F-FDG), a glucose analogue, is the standard tracer used to evaluate neoplastic tissue. The standardized uptake value (SUV) is a semiquantitative parameter used to measure tracer accumulation in tissues and SUVmax is the most widely accepted metric in clinical practice.

Aim

SUVs of healthy background tissues, such as the liver and mediastinal blood pool, are commonly used as references to define disease and assess tumor response to therapy. The aim of this study was to analyze the effects of blood glucose levels on 18F-FDG-uptake in the liver.

Materials and Methods

We retrospectively selected 250 patients who had undergone clinical PET/CT examinations from July,2025 to August,2025. Patients’ medical records were reviewed to collect data on blood glucose level at the time of 18F-FDG injection. Subjects with extensive disease in the target organ were excluded from the analysis.

Patients were further stratified into six groups based on their serum glucose levels: I) ≤100mg/dL, n=47; II) 101–120mg/dL, n=102; III) 121–140mg/dL, n=52; IV) 141-160mg/dL, n=20; V) 161-180mg/dL, n=17; VI) 181-200mg/dL, n=12.

Using the fused transaxial PET/CT images, uniform regions of interest (ROIs) were placed manually on single slices of the right lobe of the liver. Data are presented as frequencies and percentages, mean±standard deviations (SDs). For comparison of continuous variables, the Kruskal-Wallis test was used and Dunnett’s test for post-hoc comparisons to assess changes in other groups with glucose levels >100mg/dL versus the group with glucose ≤100mg/dL. We considered p values <0.05 to indicate statistical significance.

Effect size was calculated for each group with glucose >100mg/dl by dividing the difference in the group mean SUVmax by the mean SUVmax in the control group using pooled SDs. As the test-retest variability in SUVmax values used with this method has shown to be ~10%, differences in mean SUVmax between glycemic ranges were considered to be clinically significant only when >10% variation was observed.

Results

Post-hoc analysis demonstrated significant differences in liver SUVmax for two groups (161-180 and 181-200mg/dL) in comparison with the control group. However, differences in mean SUVmax for other groups (<10%) were not clinically significant.

161-180 and 181-200mg/dL have large effect sizes (d>0.5), indicating a substantial difference in SUV max compared to the <100 group. 141-160 and 121-140mg/dL has a moderate effect size (d ≈ 0.5), while 101-120mg/dL shows a small effect (d ≈0.23).

Conclusion

The effect of blood glucose level in 18F-FDG PET/CT imaging on the liver is variable. The SUVmax of the liver seems to increase in hyperglycemic patients compared to normoglycemic patients, hence liver SUVmax should be corrected for blood glucose level to be used as a reference for the detection of minimal tumor activity and assessment of response. However, the variation is small to have potential clinical relevance.

ABAOCNMB270: Evaluation of Diagnostic utility of ^99mTc MDM (DTPA-bis-MET) scintimammography in BIRADS IV & V mammographically breast lesions

Meena Negi*, Manishi L Narayan*, Vandana Kumar Dhingra*, Nilotpal Chowdhury*, Puja P Hazari**, Anil K Mishra**, Anjum Syed*

*A.I.I.M.S., Rishikesh, **I.N.M.A.S. (D.R.D.O), Delhi

Introduction

Various biomolecules i.e. Natural amino acids, antibodies and peptide-based receptors, labeled with radioactive isotopes, are available for tumor imaging using SPECT &PET technology. PET tracers are expensive and not widely available in many centres. SPECT-based tracer-^99mTc-MDM (DTPA-bis-methionine) has shown promising results with brain tumor imaging. The uptake of ^99mTc-MDM is facilitated by the upregulation of amino acid transporters and transported in tumor cells by LAT1 transporter. It could possibly be used as an effective method for the detection of malignant breast lesions.

Aim

To explore the correlation of indigenously prepared ^99mTc-MDM uptake in patients with BIRADS-IV &V breast lesions.

Methodology

A total of 49 patients(52lesions) with BIRADS-V lesions(n=36) and BIRADS-IV breast lesions(n=16)were prospectively recruited for the study. For ^99mTc-MDM labeling,15-20mCi ^99mTcO4^- was added in a vial and incubated for 15-20minutes. Approx., 15-20mCi of ^99mTc-MDM was injected intravenously to patients under gamma camera. Anterior, Lateral-Prone, whole-body & regional SPECT images were acquired at 10,60 &180minutes. Radiopharmaceutical labeling was assessed qualitatively and quantitatively. Images were correlated with Mammography & Ultrasound. For all patients, the tumor-to-background ratios were calculated at 1hr& 3hrs and statistically analyzed.

Results

Total 49 patients with BIRADS-IV &V breast lesions(n=52)were evaluated. Biodistribution of this tracer and its labelling efficiency on the scans was found to be satisfactory in all patients. Physiological tracer uptake was seen in kidneys, gall bladder, liver and bowel. The mean(SD) of Tumor-Background Ratio at 1hour was 1.57(0.48)[BIRADS-4c] and 1.59(0.39) [BIRADS-5]. At 3hours, mean(SD) of Tumor-Background Ratio was 1.64(0.39)[BIRADS-4c] and 1.58(0.44) [BIRADS-5]. In current study, a statistically significant difference observed in Tumor-Background Ratio among BIRADS 4c & 5 categories at 1hour(p=0.007) &3hours(p=0.006). Strength of association, measured by Kendall’s Tau, was 0.31 (1hour), suggesting a modest but not strong & 0.22(at 3hours), suggesting a weak positive correlation.

Conclusion

This is the first study to correlate ^99mTc-MDM imaging with BIRADS-IV&V breast lesions. In our study, there was ^99mTc-MDM uptake & retention seen in all malignant lesions. A statistically significant difference was observed between Target/Background ratio only with BIRADS-4c&5 breast lesions at 1hr& 3hrs. Although, the strength of association between T/B & breast lesion was not very strong. Current study indicate that ^99mTc-MDM Imaging is a feasible alternative to PET. However, significant tracer uptake was observed predominantly in BIRADS-4c &5 breast lesions, indicating its diagnostic utility limited to higher suspicion category lesions. Accordingly, the use of this tracer should be approach with radiological and pathological discretion within these subgroups.

ABAOCNMB270: F-18 PSMA1007: Fully automated radiosynthesis with Sep-Pak^® Plus C-18 cartridge in a GE Tracer lab _FX-FDG type module & Quality Control

Saikat Nandy¹, Promod Dodke², & Nawab Singh Baghel¹

¹ MCRPhPS, Radiation Medicine Centre (G), BARC, Parel, Mumbai-400012, ² Medical Cyclotron Facility, BRIT, Parel, Mumbai-12

Introductions

¹⁸F-PSMA-1007 is one of the best among several ¹⁸F-PSMA-ligand candidate compounds as it demonstrated high labelling yields, out-standing tumor uptake and fast, non-urinary background clearance. Since 2022, in several European countries, it is commercially available in the name of Radelumin^®. From ABX, kits are available for several cassette based radiosynthesis modules while the precursor is not till commercially available. We report first time a high yield, fully automated, radiosynthesis procedure with Sep-Pak^® plus C-18 cartridge purification in a GE Tracerlab _FX-FDG type synthesis module and quality control.

Materials and Methods

Neptis^® kit was procured from B.J. Madan & Co. QMA, QMA, C-18 Plus Sep-Pak^® cartridges, other chemicals (AR grade), Sartorius ^® 0.22 µm filters, 10 ml evacuated vials were also procured locally.

¹⁸F was produced vial the nuclear reaction ¹⁸O (p, n)¹⁸F in GEPETtrace 800 cyclotron in Nb25 target. After irradiation, it was delivered to an adapted general purpose fluorination module and ¹⁸F-was trapped in QMA cartridge. ¹⁸F is eluted in the form of TBA¹⁸F by 0.6 ml 75mM TBAHCO₃. Dry TBA¹⁸F was obtained after two steps drying using anhydrous acetonitrile (1.2 ml). 1.6 mg ¹⁸F-PSMA1007 precursor dissolved in 0.7 ml dry DMSO is added and radiofluorination was carried out at 120⁰C, 15 min. After cooling, the reaction mixture was loaded on a stand of three conditioned C 18 plus Sep-Pak^® cartridges. F-18 PSMA 1007 was eluted in 10 ml of 30% ethanol containing water and collected in vials through 0.22µ filter. Clarity, pH, radiochemical purity (radio TLC in 60/40 MeCN/H₂O and radio HPLC using C-18 reverse phase column and two reported gradient system) were checked.

Results

The total synthesis time is around 45 min with non-decay corrected yield ~ 30%. The nature of the only impurity i.e. free [¹⁸F]F^-, the product ¹⁸F-PSMA-1007 and intelligent selection of the eluting solvent is the key of purification. It is clear, colourless and free of any suspended particle. pH'5-6. RCP>95 % in both radio TLC as well as Radio HPLC method. R_f of free [¹⁸F] F^- is 0.3 whereas of ¹⁸F-PSMA-1007 is 0.6. In gradient Radio HPLC method (Joseph A. Ioppolo et al, 2022), the retention time of ¹⁸F-PSMA-1007 is around 28.2 min.

Conclusion

Pharmaceutical Grade ¹⁸F-PSMA-1007 can easily be synthesized in good yield in GETracerlab _FX-FDG type synthesis module.

ABAOCNMB243: Loading of Radioiodine (Iodine-131) on Biodegradable nanofiber patch for the therapeutic purpose of residual tumours after resection – A novel radionuclide therapy system

Ravi Kumar Chauhan ^1,2, Arvind Suresh ^1,2, Srikanth Saminathan ^1,2, Jay Prakash^1,2, Ajay Kumar^1,2, Uddeshya Narayan jha^1,2, Santosh Kumar Gupta^1,2

¹Mahamana Pandit Madanmohan Malviya Cancer Centre & Homi Bhabha Cancer Hospital, (A Unit of Tata Memorial Centre), Varanasi, UP, ²Homi Bhabha National University, Mumbai

Background

Cancer is one of the main causes of death worldwide. Surgery, chemotherapy and radiotherapy form the basis of cancer’s current treatment. However, these techniques have several disadvantages, such as surgery complications, chemotherapy systemic side effects and cancer recurrence. Hence, there is a crucial need for a novel controlled release delivery system of radiation for implantation following tumour resection to effectively prevent recurrence. Here, the nanofibrous fabricated was a blend of two different natural proteins: Soya Protein Isolate (SPI) and silk fibroin. These biocompatible and biodegradable nanofibers was prepared by electrospinning technique. In addition, radioiodine (Iodine-131) was loaded on nanofibers and these therapeutic radioisotopes loaded nanofibers had stability for approximately 30 days and exhibited a sustained release of radiation for at least 2 weeks were evaluated for implantation following tumour resection.

Objectives

The aim of this study was to encapsulate radioiodine (Iodine-131) and release of radiation from biodegradable nanofibers loaded with radioiodine.

Methods and Materials

We prepared radioiodine (Iodine-131) loaded nanofiber patch, self-assembled from biodegradable soya protein and silk fibroin without adding surfactant during the emulsification process. The obtained biodegradable nanofibrous have an open hole on the shell without the assistance of a template. Nanofibers were prepared in three different ratios Type-I SPI: SF; 75:25 (w/w), Type-II SPI: SF;50:50 (w/w), and Type-III SPI: SF;25:75 (w/w). 2mCi of radioiodine was added on each fiber patch.

Result

It was observed that Type-I nanofibrous delivered radiation slowly in vitro. The slow, sustained deliver of radiation in vivo may increase induction of apoptosis in residual tumor cells and inhibition of tumor angiogenesis.

Conclusion

We concluded that radioiodine (Iodine-131) loaded with nanofibers can be introduced as a promising treatment for implantation upon post-surgery of tumour. Animal studies will be evaluated in next step of studies.

ABAOCNMB166: Practical experiences in innovative dual tracer imaging with F-18 FDG PET/CT and low dose Lu-177 DOTATATE SPECT/CT.

Akshara P, Nandini Pandit, Vignesh H, Kabilash Dhayalan

Jawajarlal Institute of Postgraduate Medical Education and Research (JIPMER)

Introduction

PET imaging is highly useful in neuroendocrine tumors (NET) predicting the biological behavior of tumors and guiding the best treatment options, as well as for providing accurate prognosis. FDG uptake reflects the metabolic activity of the tumor and can indicate a more aggressive disease, higher histological grade, and worse prognosis, regardless of the tumor’s grade. On the other hand, somatostatin receptor (SSTR) imaging using Ga 68 DOTA(TATE/TOC/NOC) shows the degree of SSTR expression and is linked to well- differentiated tumor tissue and a better response to PRRT (peptide receptor radionuclide therapy). Using both metabolic information from F-18 FDG and receptor expression from Ga 68 DOTA, known as dual PET imaging, provides a complete view of the disease’s status throughout the entire body.

We introduced an innovative imaging technique with a low dose of Lu-177 DOTATATE to image the SSTR expression of NETs as substitute to Ga-68 radiopharmaceuticals.

Materials and Methods

In a patient biopsy with proven well differentiated NET, grade 2, Ki 67-5%, synaptophysin negative, CK20 and PSA negative. 10 mci of Lu-177 DOTATATE was injected intravenously and a delayed SPECT/CT imaging was planned after 4 hours. Meanwhile 5.84 mci of F-18 FDG was injected intravenously and PET/CT images were acquired after 74 minutes.

Result

F-18 FDG PET/CT revealed metabolically active primary lesion in the rectum with regional lymph nodal metastasis, liver metastasis and extensive skeletal metastasis. But low-resolution images of the patient with poor identification of localizing sites was noted in the Lu-177 DOTATATE low dose image. The poor quality of image was observed because of the 511 keV photons of F-18 that undergo Compton scatter inside the patient or the detector. Though scattered, 511 keV photons lose energy and fall into the Lu-177 energy window. This produces spurious counts in the Lu-177 SPECT images, increasing background noise and reducing contrast. A delayed 24-hour SPECT/CT was obtained where SSTR imaging was interpretable. The scan revealed multiple skeletal and liver metastasis and possible lymph nodal metastasis.

This was possible due to the long half-life of Lu-177 and earlier decay of F-18 FDG.

Conclusion

We propose that LU-177 DOTATATE may be used as a surrogate imaging method to Ga-68 SSTR imaging. Delayed imaging is one of the techniques that can be used to overcome the interference of PET imaging when performed on the same day. Delayed imaging continues to be an effective tool and adds significant information in the era of theranostics.

ABAOCNMB194: Commissioning of facility for production and quality control of ²²⁵Ac-labelled Radiopharmaceuticals at RMC for clinical use.

M K Ray and S Basu

Radiation Medicine Centre, BARC, TMH Annex, Parel Mumbai 400012

Introduction

Role of Actinium-225 (Ac-225) in targeted alpha therapy (TAT) as a promising radionuclide for cancer treatment has emerged due to its potent cytotoxicity and favourable decay characteristics. Establishing a dedicated Ac-225 labelled radiopharmaceutical production facility at RMC required technical, regulatory, and logistical challenges. These abstract outlines the core components and considerations for such a facility.

Materials and Methods

Proposal for seeking clearance for setting up of a facility for production and quality control ²²⁵Ac-labelled radiopharmaceuticals in the Hospital Radiopharmacy Section, RMC was submitted to the Local Safety Committee in December 2019. The space for starting the facility was identified. The Objective and the Action Plan including individual internal monitoring of the radiation workers involved in handling ²²⁵Ac, SOP of the preparation of the ²²⁵Ac-radiopharmaceuticals, safety aspect of workstation, Emergency Operation Procedure (EOP) related matters, were meticulously discussed and documents drafted. Approval for storage and disposal of radioactive waste pertaining to ²²⁵Ac was obtained from Waste Management Division of BARC. Provision for personnel monitoring of alpha contamination was arranged. Final approval for commissioning the facility was requested to the apex body of BARC Safety Council- Operating Plants Safety Review Committee (OPSRC).

Results

The OPSRC recognised the benefits of ²²⁵Ac in cancer therapy and provided its concurrence for commissioning the facility. The commissioning of the facility was done under the supervision of Unit level Safety Committee-Radiological Operations (ULSC-RO), BARC. RMC was provided the license to use 37,000 kilobecquerel of activity of ²²⁵Ac. The mandatory monitoring of radiation workers involved in the preparation of ²²⁵Ac-RP for internal contamination was done and level was found to be below detection limit (BDL).

Conclusion

The objective of RMC is to provide diagnostic and therapeutic Nuclear Medicine services at affordable cost. The first alpha therapy was provided in July 2021. Till today 19 batches of ²²⁵Ac-DOTATATE and 15 batches of ²²⁵Ac-PSMA-617 has been prepared and provided to RMC clinics for patient use.

ABAOCNMB278: Mavorixafor as a CXCR4-Targeted Scaffold for the Development of ⁶⁸Ga-DOTAGA-Thioureido Conjugated Radiopharmaceutical for Theranostic Applications

Harshita Singh^1,2, Pankaj Deshwal¹, Nitin¹, Sukhvir Singh², Sanjiv Shaw³, Teena Goel⁴, Neetu Singh⁵ and Puja P Hazari^1*

¹Department of Cyclotron and Radiopharmaceutical Research, Institute of Nuclear Medicine and Allied Sciences, DRDO, ²Radiation Safety Cell, Institute of Nuclear Medicine and Allied Sciences, DRDO, ³Department of PET Imaging and Nuclear Medicine, INMAS, DRDO, ⁴Regional Centre, Board of Radiation and Isotope Technology, DAE, ⁵Center for Biomedical Engineering, Indian Institute of Technology, Delhi

Introduction

CXCR4 is a clinically relevant chemokine receptor implicated in tumor progression, metastasis, and immune cell trafficking, making it a compelling target for theranostic radiopharmaceuticals. Mavorixafor, an FDA-approved selective CXCR4 antagonist with a favorable pharmacokinetic and safety profile, offers a promising scaffold for molecular imaging and targeted radionuclide therapy. This study explores the conjugation of Mavorixafor with p-NCS-Bz-DOTA-GA via thioureido linkage, enabling stable complexation with gallium-68 (⁶⁸Ga) for PET imaging. We present a synthetic strategy for the DOTAGA-Bz-thioureido-Mavorixafor construct, evaluate it’s radiolabeling efficiency, and assess in vitro and in vivo CXCR4 binding affinity and serum stability.

Materials and Methods

The molecular docking and ADME studies were conducted in which the compound was docked to CXCR4 receptor protein using Autodock Vina. The analysis of the obtained affinity score favored bifunctional chelator bound compound as lead ligand for the targeted receptor. Mavorixafor, a potent and selective small-molecule antagonist of CXCR4 recently approved by the FDA for WHIM syndrome, was selected for conjugation due to its established clinical safety profile and high affinity for CXCR4. For synthesis, mavorixafor (1mg) and p-NCS-Bz-DOTA-GA (1.90 µM) were vortexed at 240 rpm in sodium bicarbonate buffer solution (pH 9). The synthesized compound was characterized through mass spectroscopy and nuclear magnetic resonance. The synthesized conjugate was radiolabelled with Gallium-68 by adding the generator eluate directly into the vial containing the compound and sodium bicarbonate buffer. The product was purified and analyzed by high-performance liquid chromatography. The in vivo PET imaging was performed on healthy rabbit. Ex vivo biodistribution studies were performed on healthy mice (n=3) where the organs of the animal were excised at 1h, 2h, 4h, and 24h p.i.

Results

Docking studies suggested a lower affinity score of -19.1kcal/mol, suggesting efficient binding of ligand to receptor. Radiolabeling was successfully completed in 15 minutes at 95°C. The radiochemical purity of the radiolabelled compound was found out to be >95% at a linear gradient of acetonitrile and water. Liver and kidney showed a higher uptake suggesting hepatobiliary route of excretion.

Conclusion

The high radiochemical purity and efficient binding of the synthesized product support its potential as a CXCR4 targeting theranostic agent. This conjugation will facilitate radiolabeling with Gallium-68, Copper-64, and Scandium-44 radioisotopes, enhancing the compound’s utility as a theranostic agent. This study highlights a promising potential of the radiopharmaceutical in imaging and targeted therapy.