SNMICON 2024 Abstracts

Abstract ID: 44: 99mTc-glucoheptonic acid as a tracer for clinical use in brain tumour imaging

M. K. Ray¹, N. T. Bivinjith^1,2, Ashok R. Chandak^1,3, Nikhil Mohan², T. H. Asalah²

¹Radiation Medicine Centre, BARC, Mumbai, ³Board of Radiation and Isotope Technology, Navi Mumbai, Maharashtra, ²Malabar Cancer Center, Thalassery, Kerala, India

Introduction: Brain tumor is the second most common childhood malignancy, and it is a common cause of cancer-related deaths in middle-aged adults. Glioma and meningioma are the common primary brain tumour in adults. 99mTc-Glucoheptonic acid (GHA) is one of the excellent radiopharmaceuticals for brain tumour imaging. It is introduced and used as a renal imaging agent since last few decades. Recently it is explored for brain tumour recurrence imaging agent. CT scan and MRI can provide anatomical location of tumour and classifying grade of the tumour separately. Radionuclide imaging modality is useful for evaluation of malignant lesion and grading of the tumour at once. BBB disruption or capillary leak is variable in different grades of glioma, which is higher in high-grade tumors and limited in low-grade tumors. The aim of present study was to detect residual tumor after primary treatment with surgery/radiotherapy using 99mTc-GHA.

Materials and Methods: The GHA cold kit (TCK 15) was used for labeling with 99mTcO4- supplied by BRIT, Navi Mumbai. Kept the cold kit vial at ambient conditions and added 2-3 mL of 99mTcO4- (60 mCi) for the labeling. Injected 20 ± 2 mCi of the activity intravenously in to the patients (6 patients aged between 55-65 years) for the brain tumour imaging. 99mTc-GHA SPECT (NM/CT 640, GE Healthcare was performed at Malabar Cancer Center, Thalasseri for brain tumor evaluation. Its uptake is predominantly dependent on BBB disruption. Early imaging and delayed scanning was done to calculate the retention of the activity at the site of the tumour. Reconstruction of SPECT-CT data was done using standard software. Reconstructed images were reviewed in 3 axes.

Results: Early images were acquired at 30 minutes and delayed SPECT-CT images were taken after 2 hours of the injection. The images of the 99mTc-GHA patients were showing tumor to normal brain background (T/N) ratio in between 6-8 ± 2.5 (SUVmax). We have found higher concentration of tracer uptake at tumour site and was compared to normal brain tissue uptake.

Conclusions: 99mTc-GHA is a good radiopharmaceutical option for imaging high-grade brain tumors, detection of residual tumor after primary treatment with surgery/radiotherapy and also for detecting recurrence. The image data will be compared with 68Ga-PSMA for specificity with more patients for better statistical correlation.

Abstract ID: 53: The utility of 18F FDG neuro PET CT imaging in diagnositic workup of patients with clinical suspicion of progressive supra nuclear palsy

Bukke Surekha, Tekchand Kalawat, R. Ramya Priya

Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India

Introduction: Parkinsons plus syndromes is group of neurodegenerative disorders which includes Frontotemporal Dementia (FTD), Corticobasal Degeneration (CBD), Multiple System Atrophy (MSA), Progressive Supranuclear Palsy (PSP), Dementia with Lewy Bodies (DLB) and Vascular Parkinsonism with overlapping of symptoms and often they are inappropriately labelled on basis of overlapping clinical symptoms. In this study we evaluated the symptom profile of clinically diagnosed PSP patients and correlated them with the 18F FDG NEURO PET CT findings.

Materials and Methods: In this study, we retrieved clinical records of patients with Parkinson plus syndrome (PSP) data from hospital information system patient records and department of nuclear medicine library from the year 2017 to 2023. Clinical findings and 18F FDG PET CT findings of all the patients were retrieved and correlated.

Results: A data of n=35 clinically diagnosed PSP patients retrieved from the above-mentioned time period with mean age of 60.3 ± 11.1 years, 21/35 (60%) were males and 14/35 (40 %) were females. We observed majority of patients were associated with PSP related symptoms after 60 years with male preponderance. Females are equally affected below 60 years of age. Based on clinical symptom profile patients were sub grouped into Richardson syndrome (PSP-RS) type 23/35 (65.7%) and into predominant parkinsonism (PSP-P) type 12/35 (34.2%). PSP-RS subtype primarily presented with postural instability 20/23 (86.9%) and cognitive decline 12/23 (52.1%). whereas, the PSP-P sub type was by bradykinesia and tremors 12/12 (100%). In 18F FDG PET CT both these sub groups had global symmetrical hypometabolism, with frontal lobe 25/35 (71.4%) being most frequently affected brain area followed by temporal lobe 17/35 (48.5%). 3/12 (25%) PSP-P type had involvement of basal ganglia while PSP-RS type had out number in 10/23 (43.4%) patients.

Conclusions and References: 18F FDG NEURO PET CT imaging is a highly useful molecular imaging technique for evaluation of neurodegenerative and movement disorders. This study highlighted the utility of 18F FDG brain PET scan finding in PSP patients by demonstrating unique bilateral cerebral decrease metabolism with further prominently reduced metabolism in frontal and temporal lobes and segregates them from other types of Parkinson plus syndromes. These observations are highly useful and complementing the clinical diagnosis of PSP and serves as a imaging biomarker for early diagnosis of PSP and its treatment planning.

Abstract ID: 65: Role of 18F-FDG PET/CT in detection of Alzheimers disease at early stages in comparison with MRI

M. Srivignesh, E. Venkatachalapathy, M. Palani, K. Sibu, G. Sakthivelayudham, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline, memory impairment, and behavioral changes. Early diagnosis is essential for managing the disease, improving patient outcomes, and slowing its progression. Imaging technologies like F-18 FDG PET (positron emission tomography) and MRI (magnetic resonance imaging) are critical tools in diagnosing AD. F-18 FDG PET measures cerebral glucose metabolism, revealing early neuronal dysfunction, often before structural damage appears. MRI, meanwhile, captures high-resolution images of brain anatomy, identifying atrophy and structural abnormalities. This study aims to compare the functional data from FDG PET with the anatomical information from MRI, focusing on their roles in early AD diagnosis and disease monitoring.

Materials and Methods: In this retrospective study, 15 patients with mild cognitive impairment (MCI) and suspected early-stage Alzheimer’s underwent neuropsychological testing, F-18 FDG PET, and MRI. F-18 FDG PET measured cerebral glucose metabolism, particularly in the posterior cingulate, precuneus, and parietotemporal regions, which typically exhibit hypometabolism in early AD. MRI analyzed structural changes, including hippocampal volume and cortical thickness. Additionally, volumetric analysis and voxel-based morphometry (VBM) were performed to assess brain atrophy. Imaging results were correlated with cognitive performance and compared across various dementia types.

Results: Out of 15 patients who have undergone both PET/CT and MRI F-18 FDG PET detected hypometabolism in AD-specific regions in all 15 patients, often before cognitive decline or structural atrophy appeared on MRI. MRI revealed significant hippocampal atrophy in 8 cases, correlating with more advanced cognitive impairment.

Conclusions and References: F-18 FDG PET is highly sensitive in detecting early metabolic changes in AD, often preceding structural changes seen in MRI. MRI is crucial for excluding other causes of cognitive decline. Combining both modalities enhances diagnostic accuracy, allowing for earlier intervention and more personalized management of Alzheimer’s disease.

Abstract ID: 123: Unveiling additional brain perfusion defects, seizure foci in children with focal lesional epilepsy using Inter-ictal 99mTc-ECD brain SPECT/CT

S. Ramya, Manishi L. Narayan, P. K. Panda, S. Indar Kumar, J. Chaturvedi, S. Sarath

All India Institute of Medical Science, Rishikesh, Uttarakhand, India

Introduction: Seizure being a dynamic process, the cerebral perfusion and metabolism alters drastically during and after seizure. Nearly 50% of children with focal seizures are known to have an underlying etiology and high risk of developing drug-resistant epilepsies and eventually warranting surgery. 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 surgical management, ultimately enhancing disease management and improving patient outcomes.

Aim: To observe the scintigraphy features in pediatric 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 0.2-0.3 mCi/kg of 99mTc-ECD. Tracer was slowly injected intravenously, with patient at rest in a dim light room with eyes open. Imaging was acquired 45-60 minutes post-injection. Location of perfusion defects were analyzed both visually and using semi-quantitative methods.

Results: A total of 28 children, having seizures for >2 years of duration (18-male & 10-female) with lesional epilepsy were analysed. Out of these, 9/28 (32%) had Right focal seizures, 12/28 (43%) had left focal seizures and rest of the patients have either absence or generalized seizures. EEG performed revealed concordant findings with 14/28 (50%) patients and discordant findings in 14/28 (50%), out of which 12/28 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, 39%), gliosis/ cysts or granuloma in 21% (n=6), white matter abnormalities in 21% (n=6), focal cortical dysplasia in 4 children (14%). Inter-ictal brain perfusion SPECT showed concordant sites of defects in 23/28 (82%) patients, with additional site of defects identified in 14/28 (50%) cases. Most of the additional sites of perfusion defects were temporal lobe hypoperfusion followed by pre-frontal, orbito-frontal, pre-cuneus defects.

Conclusions and References: 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.

Abstract ID: 138: Diagnosis of CSF leak – 99mTc-DTPA CSF cisternography in a rare case of posttraumatic subdural collection

Ragire Sainath, Harinee Ganesan, Vasanth Madivanane, A. M. Lakshman, Sathyanarayanan, Gopinath Gunasekaran, Madhusudhanan Ponnusamy

Department of Nuclear Medicine, JIPMER, Puducherry, India

Introduction: Cerebrospinal fluid (CSF) leak is a notable complication following traumatic brain injury (TBI), with significant implications on patient outcome. Early diagnosis and effective management are crucial to prevent complications like bacterial meningitis, tension pneumocephalus, etc. Hence, prompt diagnosis of CSF leak is required to decide the appropriate treatment. Here we report a 51 year old male who presented with traumatic head injury, on evaluation found a progressive subdural collection which was diagnosed as CSF leak in 99mTc-DTPA CSF Cisternography, thus emphasizing its role.

Materials and Methods: The patient presented to our casualty with a history of road traffic accident under the influence of alcohol, sustaining head injury with loss of consciousness for 1 hour, facial injury on right side, chest injury and pain. NCCT Brain showed normal brain parenchyma with fracture of zygomatic arch, right side body and symphysiomental part of mandible. The patient was managed conservatively. NCCT Brain after a week showed fracture of zygomatic arch, right mandible and suspected right subdural hematoma/hygroma with increase in collection on serial NCCT Brain. MR cisternography was done which showed T2 hyperintense collection noted in the right frontal, temporal and parietal lobes, a differential diagnosis of right subdural hematoma/hygroma and CSF leak was made. 99mTc-DTPA CSF Cisternography was performed to confirm the diagnosis.

Results: Delayed static images at 4 hours revealed tracer distribution in the spinal cord, basal cisterns, lateral, third and fourth ventricles. Abnormal diffusely increased tracer uptake was noted in the right frontal, parietal, and temporal regions. SPECT/CT reveals abnormal tracer uptake in a subcranial fluid collection overlying the right frontal, temporal and parietal lobes, confirming CSF leak.

Conclusions and References: This case emphasizes the vital role of 99mTc-DTPA scintigraphy in the diagnosis of trauma induced CSF leak.

Abstract ID: 217: Mapping the sparks: Combined ictal and interictal Tc-99m ECD SPECT in frontal lobe epilepsy diagnosis

Harinee Ganesan, Kabilash Dhayalan, Vasanth Madivanane, Ragire Sainath, Madhusudanan Ponnusamy

JIPMER, Puducherry, India

Introduction: Epilepsy, one of the most prevalent neurological disorders, does not sufficiently respond to pharmacological treatment in a significant proportion of the patients. Surgical resection of the epileptogenic zone offers a high chance of cure for individuals with drug refractory epilepsy. This requires accurate localization of the epileptogenic zone prior to surgery. If one of the conventional pointers to the epileptogenic zone assessed during presurgical evaluation (MRI and electroencephalography (EEG)) is absent, or if there is discrepancy between these pointers, more sophisticated imaging is needed. Thus, ictal and interictal brain perfusion single-photon emission computed tomography (SPECT) helps, especially in frontal lobe epilepsy (FLE) which is often difficult to diagnose. Here we report a case in which ECD ictal and interictal SPECT localized the epileptogenic focus when MRI & EEG were inconclusive.

Materials and Methods: A 11 years old male child presented with complaints of production of abnormal sound for a year, initially during night, progressed to day time as well. No history of breathing difficulty, swallowing difficulty, change in voice. On examination, laryngeal crepitus was present. MRI Brain was done which revealed mild architectural distortion in the left hippocampus with no volume loss, possibly partial inversion and no abnormal signal changes, Arterial Spin Labeling (ASL) showed no perfusion abnormality with rest of the bilateral cerebral hemispheres showed normal parenchyma and gray white differentiation. EEG demonstrated a 30 minute normal recording. Clinically suspected with frontal lobe epilepsy, so Tc-99m ECD ictal and interictal SPECT was done to look for the epileptic focus.

Results: Ictal SPECT 1 hour after injection revealed normal-to-mildly increased tracer uptake in the posterior part of the right frontal cortex. Rest of the cerebral and cerebellar cortices, bilateral basal ganglia, and thalami show good tracer uptake. Interictal SPECT 1 hour after injection revealed a focus of moderately reduced tracer uptake in the posterior part of the right frontal cortex. Suggesting epileptogenic focus in the posterior part of the right frontal cortex.

Conclusions and References: This case underscores the utility of combined ictal and interictal Tc-99m ECD SPECT when the conventional modalities are inconclusive, thereby helping in localizing the epileptogenic focus and further management of the patient.

Abstract ID: 35: Stimulated thyroglobulin level in differentiated thyroid carcinoma: Improvised role in guiding follow-up

Keerthana Kiran Kandula, Kanhaiyalal Agrawal, Parneet Singh, Kishore Kumar Behera, Girish Kumar Parida, P. Sai Sradha Patro

All India Institute of Medical Sciences, Bhubaneswar, Odisha, India

Introduction: Serum Thyroglobulin (Tg) is a well-established marker used in management of patients with differentiated thyroid cancers (DTC). High-sensitivity Tg tests are crucial in early detection of recurrence. Various guidelines including European Society for Medical Oncology and the American Thyroid Association (ATA) recommends use of Tg for guiding management of the thyroid cancer patients. On follow up, stimulated Tg (STg) levels <1 ng/ml is defined as excellent response post RAI treatment. ATA suggests no need of follow up whole body radioiodine scan (WBIS) in patients with low risk of recurrence and STg <1 ng/ml. We studied role of follow-up undetectable STg in DTC patients in all ATA risk categories.

Materials and Methods: We retrospectively analyzed data of 378 DTC patients, who were referred to Nuclear Medicine department post thyroidectomy for further management. 31 patients with raised anti-Tg levels were excluded from study. Patients were divided into two groups, Group 1 with STg < 1 and Group 2 with STg value >1. The initial risk of recurrence in patient was assessed using ATA criteria and were stratified into low, intermediate and high-risk categories. The findings of WBIS on 6 month follow up post radioiodine ablation/therapy was also analyzed in all six groups. The results were calculated in percentage.

Results: A total of 347 patients (97 male and 250 female, mean age 38.03 years) were included in the study; of these, 123 had low risk, 147 had intermediate risk, and 77 patients had high risk. In all three-risk category with STg < 1 ng/ml and negative Anti-Tg, WBIS shows no abnormal uptake. In low-risk category, even though none of the patients showed any abnormal on WBIS, STg value was >1 ng/ml in 97 patients.

Conclusions and References: To summarize, the WBIS can be avoided at follow up in patients with STg less than 1 ng/ml and negative anti-Tg level in all risk category defined by ATA. This can safely avoid the morbidity associated with achieving a hypothyroid state for WBIS.

Abstract ID: 51: Surveillance of patients who received 185 MBq radioiodine ablation for hyperthyroidism in a tertiary care centre for the past 25 years

Asha Rose Jose, Justin Benjamin, Julie Hephzibah, Felix Jebasingh

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Though radioiodine ablation (RAIA) has been used for more than 75 years in the management of Graves’ thyrotoxicosis, it is still debatable whether to opt for a calculated dose versus a fixed-dose, or high dose versus low dose. In our institute the fixed-dose protocol administration of 185 MBq of I-131 has been used over the last 40 years. Through this, we render to make our patients euthyroid which is undeniably better than lifelong striving hypothyroidism, or they go into hypothyroidism in a gradual, sustained manner. This retrospective study aims at collecting data of all patients who underwent RAIA in our institute in the last 25 years with periodical follow up and assess their response to treatment, various complications endured and compliance to treatment.

Materials and Methods: All patients who underwent radioiodine ablation for hyperthyroidism in our institute from 01/01/1996 to 06/06/2020 with a minimum follow up of 10 years from 1996-2012 and 2 years from 2013-2022 were included in the study. Data was obtained from hospital records and picture archiving and communicating systems (PACS). All patients were followed up for a period of six months, one year, two years, five years and ten years and analysis of patient data was carried out at regular time intervals. The response outcome was classified to be hyperthyroid, euthyroid and hypothyroid based on their thyroid function tests and clinical symptoms. Achievement of euthyroidism/hypothyroidism at any point was considered a successful outcome.

Results: A total of 529 out of 2444 patients were included in the final analysis, predominantly females (72.4%) and of younger age group (median age of 41 years). The median follow up was 6 years. Regarding the hormonal status at each time point of 6 months, 12 months, 2 years, 5 years and 10 years, majority of patients were observed to be hypothyroid - 48%, 54.4%, 62.6%, 49.1% and 35.7% respectively. Around 2.8% patients developed recurrence during their course of treatment. About 14% and 1.7% patients required a second and third ablation respectively in the follow up period. Pertaining to this treatment, minimal long-term complications were noted, namely ischemic heart disease (0.4%), atrial fibrillation (0.4%) and malignancy (0.8%), with no thyroid related malignancies.

Conclusions and References: This study series has confirmed that RAIA is a safe as well as effective definitive treatment for hyperthyroidism with majority of patients being rendered hypothyroid with a single low dose of 185 MBq of I-131.

Abstract ID: 72: Comparison of thyroid uptake value between thyroid uptake probe and gamma camera

P. Aadhavan, Jaisurya, Prabu Titus Devakumars, Julie Hephzibah, Saumya Sara Sunny, Junita Rachel John, Sandra Maria Ignatious

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Thyroid uptake studies are essential for evaluating the functional status of the thyroid gland by measuring Iodine-131 uptake. Traditionally, a thyroid uptake probe has been used for this assessment. However, advancements in gamma camera technology present alternative methods. This study compares the effectiveness of gamma cameras against traditional probe-based measurements. To quantitatively compare thyroid uptake values obtained using a thyroid uptake probe and gamma camera techniques.

Materials and Methods: We conducted a retrospective analysis of 76 patients (16 males, 60 females; ages 18-45, median age 30) with benign thyroid disorders, primarily hyperthyroidism, most of whom had been referred for evaluation before radioiodine treatment in our hospital between November 2023 to may 2024. Thyroid uptake measurements were performed using the vendor-1 gamma camera for 46 patients and the vendor-2 gamma camera for 30 patients. Each patient received 131-I (27 μCi [1 MBq]), and 24-hour thyroid uptake percentages were calculated using both methods with a high-energy collimator, defining regions of interest (ROI) in reference and neck images acquired after 24 hours.

Results: In the vendor-1 group, uptake values ranged from 17.9% to 85.7% (gamma camera) and 18.1% to 86.8% (probe). For the vendor-2 group, values ranged from 21.1% to 86.4% (gamma camera) and 24.0% to 87.0% (probe). The mean difference in uptake values was 1.7% for the vendor-1 gamma camera and 3.4% for the vendor-2 gamma camera.

Conclusions and References: Gamma camera methods are viable alternatives to probe-based measurements for thyroid uptake assessment. Despite a slightly higher mean difference with the vendor-2 gamma camera, both methods showed statistically insignificant differences, indicating that gamma cameras can reliably evaluate thyroid function, especially when dedicated probes are unavailable in resource limited setting.

Abstract ID: 82: Utility of 99MTC-pertechnetate thyroid scan in differentiation of thyroiditis v/s hyperthyroidism

G. Keerthana, E. Venkatachalapathy

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Hyperthyroidism is commonly characterized by elevated levels of thyroid hormones, leading to symptoms such as weight loss, tremors, and palpitations. However, in some cases, the clinical presentation can be misleading. Thyroiditis, a transient inflammatory condition, can mimic hyperthyroidism due to the release of preformed thyroid hormones. This case aims to highlight the diagnostic challenge presented by thyroiditis in a patient with biochemically confirmed hyperthyroidism, emphasizing the role of nuclear medicine thyroid scintigraphy in differentiating between these conditions.

Materials and Methods: 20 cases presented with classic symptoms of hyperthyroidism. Blood tests revealed elevated free T4 and suppressed TSH levels. To confirm the diagnosis and determine the underlying cause, a nuclear medicine thyroid scan using Technetium-99m pertechnetate (99mTc) was performed. The scan was evaluated for thyroid uptake to differentiate between hyperthyroidism and thyroiditis.

Results: While the patient’s blood results strongly indicated hyperthyroidism, the nuclear medicine scan showed significantly reduced or absent thyroid uptake, suggestive of thyroiditis. This finding is consistent with the pathophysiology of thyroiditis, where preformed thyroid hormones are released, but new hormone synthesis is suppressed, resulting in low radiotracer uptake.

Conclusions and References: This case underscores the importance of integrating nuclear medicine imaging with biochemical testing in patients presenting with hyperthyroidism. Thyroid scintigraphy, particularly with 99mTc, plays a crucial role in differentiating hyperthyroidism from thyroiditis, guiding appropriate management. While biochemical markers may suggest hyperthyroidism, imaging findings can alter the diagnosis and treatment plan, as seen in this case of thyroiditis, which typically requires conservative management rather than the antithyroid therapies used for hyperthyroidism.

Abstract ID: 89: Role of 99m technetium thyroid scan in assessment of cases of congenital hypothyroid – An institutional experience

Madan Gopal Vishnoi, Anurag Jain, Sumit Kumar, Rajeev Kumar, I. P. Dubey, A. V. S. Anil Kumar

Army Hospital R and R, Delhi, India

Introduction: Congenital hypothyroidism (CH) is the most common preventable causes of intellectual impairment in infants. It can cause irreversible neurodevelopment delay if not corrected with thyroxin replacement in infants. It has a worldwide annual incidence of 1:4000 live births. The etiology of the CH is very important in deciding disease severity, outcome, treatment and monitoring. TC-99m scan can provide information about the size, location and functional state of thyroid gland.

Materials and Methods: A prospective observational study conducted at Army hospital (R&R) over the period of 3 year from August 2021 to August 2024. Study comprises of 25 children of diagnosed cases of congenital hypothyroidism who were subjected for 99mTc thyroid scan. All the patient undergone thyroid function test (TFT), USG neck and Tc thyroid scan.

Results: 25 children included in the study ranging from age of 28 days to 11 yrs. There are 9 female and 16 male childrens. TFT of all the children’s reveals low T4, T3 and high TSH level. Avg TSH level is > 10 uiu/ml. According to TFT, USG and Tc thyroid scan result children are divided in four groups.

Conclusions and References: Congenital hypothyroidism is one of the most serious and preventable condition which needs to be diagnosed as early as in the newborn period. Screening for CH should include USG neck and Tc thyroid scan along with TFT. It is very important to perform technetium scanning to see the exact etiology of the CH, that helps in predicting the prognosis and planning long term management.

Abstract ID: 97: Role of 99mTc-RGD scintigraphy in identifying residual/metastatic differentiated thyroid carcinoma after thyroidectomy and radioactive iodine therapy – A pilot study

Harinee Ganesan, Vasanth Madivanane, Anirudh Abu Srinivasan, Nishaant Ramasamy, Kabilash Dayalan, Madhusudhanan Ponnusamy

JIPMER, Puducherry, India

Introduction: Differentiated thyroid cancers (DTCs) usually have favorable prognosis following surgery +/-radioiodine treatment. The existence of radioactive iodine-refractory DTC (RAIR-DTC) presents a challenge to the treating physicians. Integrin αvβ3, highly expressed by both tumor cells and activated endothelial cells, plays a pivotal role in tumor angiogenesis and metastasis. 99mTc-labeled RGD (arginine-glycine-aspartate) imaging is found to be a promising marker of tumor angiogenesis and useful to assess disease progression and extent in patients with RAIR-DTC. In this study, we aim to compare the lesions detected by 99mTc-RGD Scintigraphy in identifying residual/metastatic DTC with Iodine Whole-body scan (WBS).

Materials and Methods: In this single center ongoing study we recruited 36 intermediate & high risk DTC patients who underwent thyroidectomy and radioactive iodine (RAI) therapy. The first radioiodine treatment was given at an interval of minimum 4 weeks after surgery and the patients were asked to come for follow-up after 6 months. During follow-up after the RAI treatment TSH level of >30 microIU/L was ensured in preparation for diagnostic 131I-WBS. Serum Tg was performed in all the patients. (99mTc) Tc-RGD scanning was performed in all the patients. On the same day Iodine was given orally and patients were called after 48 hours for 131I-WBS acquisition.

Results: Out of 36 patients (mean age 47±10; 24-females, 12-males) (intermediate risk-17; high risk-19), seventeen had residual and seven had metastatic disease. By per-patient analysis, the area under the curve of 99mTc-RGD Scintigraphy was comparable to that of 131I-WBS. For per lesion analysis, both 99mTc-RGD Scintigraphy and 131I WBS found two skull and one lung metastases in a total of three patients and residual is found in 12 patients in 99mTc-RGD Scintigraphy and 17 patients in 131I WBS. The ratio of Tumor/Background increases with DTC upstaging.

Conclusions and References: 99mTc-RGD Scintigraphy has a concordant sensitivity in detection of metastasis in high risk DTC although 131I WBS has higher sensitivity in detection of residual disease. 99mTc-RGD Scintigraphy can be used as an alternative for 131I-WBS in detection of metastatic lesions as it provides favorable scintigraphic characteristics and further contributes to evaluation of tumor angiogenesis with future theranostic implications.

Abstract ID: 140: Evaluation of hereditary versus sporadic medullary thyroid carcinoma with baseline 68Ga-DOTANOC PET/CT – A descriptive tertiary center experience from India

Chandrasekaran Ganapathy, Akhil Venugopal, Nishikant Damle, V. Kowshik, S. Aakash Aravindh, C. S. Bal, G. B. Priyanka, Yashdeep Gupta, Preeti Namjoshi, Sunil Chumber, Piyush Ranjan, Gopal Puri, Shipra Agarwal

Department of Nuclear Medicine, AIIMS, New Delhi, India

Introduction: Medullary thyroid carcinoma (MTC) originates from parafollicular C-cells, often involving RET-oncogene mutations. While 75% of cases are sporadic, 25% are familial (MEN-2A, MEN-2B, and familial MTC). In India, though SSTR PET/CT is widely used, though ATA guidelines do not specifically mention its role in treatment-naïve or recurrent MTC. This study explores the utility of 68Ga-DOTANOC PET/CT in MTC with a focus on variability in imaging findings and clinical presentation in patients with sporadic and hereditary MTC who underwent baseline 68Ga-DOTANOC PET/CT.

Materials and Methods: We retrospectively reviewed data of MTC patients who underwent baseline 68Ga-DOTANOC PET/CT at our institute between January 2017 and August 2024. Patients were classified as syndromic/familial or sporadic based on family history and clinical presentation. Histopathological data were assessed for those undergoing biopsy or surgery, while clinical and biochemical correlations were performed for others.

Results: Forty-three patients (17-men, 26-women) with histologically confirmed MTC underwent 68Ga-DOTANOC PET/CT: 18 with familial/syndromic MTC and 25 with sporadic MTC. Most common presentation in the sporadic MTC group (11-men, 14-women; mean age-43.5 years, range 29–67 years) was a neck mass. The mean primary tumor size (anteroposterior dimension) was 4.8 cm (range 1.2–7.7 cm). Nearly all patients (22/25, 88%) had somatostatin receptor (SSTR)-expressing locoregional lymph nodes, and 40% (10/25) had distant metastases with the common sites being lungs (6/10), liver (3/10), and bones (3/10). In the hereditary MTC group (6-men, 12-women; mean age-30 years, range 16–43 years), 94% (17/18) had a clinically suspected/diagnosed MEN-2 syndrome, while one had concurrent left glomus-jugulare tumor. MTC was incidentally diagnosed in 15/18 (83%) patients during PET/CT scans conducted for pheochromocytoma assessment (7/18, 39%), post-adrenalectomy follow-up (4/18, 22%), or family screening (4/18, 22%). Only one patient had distant metastatic disease and the mean tumor size being 2.9 cm (range 0.8–4.2 cm). Only 3/18 (17%) hereditary MTC patients had clinical symptoms (neck swelling and tested for calcitonin levels which were elevated), with 2/3 (66%) showing distant metastases and the mean primary tumor size being 4.5 cm (range 3.8–5.2 cm). Concurrent bilateral and unilateral pheochromocytomas were detected in 7/18 (39%) and 4/18 (22%) patients respectively while two patients had meningioma.

Conclusions and References: Patients with sporadic MTC tend to be older and present with more advanced locoregional and distant metastatic disease than hereditary MTC patients, who are younger and benefit from improved surveillance. 68Ga-DOTANOC PET/CT is a highly effective imaging tool for establishing baseline disease burden, restaging post-surgery, assessing treatment response, detecting recurrence, and surveillance.

Abstract ID: 154: Thyroid scintigraphy as a key diagnostic tool in congenital primary hypothyroidism: Insights from five cases

Vishal Jain, Manishi L. Narayan, S. Ramya, R. Priyanka, S. Rinkal

All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Introduction: Congenital primary hypothyroidism (CH), affects~0.97/1,000 newborns, characterized by a deficiency of thyroid hormone at birth, commonly resulting from thyroid dysgenesis/agenesis/dyshormonogenesis. This review analyses various clinical presentations and thyroid scintigraphy (TS) patterns, with a focus on the role of TS in identifying etiopathogenesis of CH.

Materials and Methods: Five cases with CH referred to our centre between 2021-2024 for TS were retrospectively analysed. 99mTc-pertechnetate TS was performed using standard protocol (SNMMI/EANMguidelines).

Results: Case-1: 16 Y/male who presented with grade-II-goiter, features of cretinism and cognitive impairment. He was on inadequate thyroxine supplementation of 100 µg/day for three years. TS showed a diffusely enlarged thyroid gland with increased trapping function, indicating potential diagnosis of dyshormonogenesis with possible organification defect. After confirmation of diagnosis, his dose was adjusted 175 µg/day of thyroxine and is now leading an independent life. Case-2: 37 y/F presented to hospital very late with features of cretinism, CH, myxedema, polymenorhagia & anemia with S.TSH>150 uIU/ml. She had orthotopic hypoplastic thyroid gland on USG with absent pertechenate uptake on TS, suggestive of trapping function defect of thyroid. Case-3: 7 y/F with grade-II-goiter for 4 years and S.TSH=338 uIU/ml. USG neck revealed enlarged heteroechoic gland. TS revealed enlarged thyroid gland with increased trapping function, suggesting possible diagnosis of dyshormonogenesis with organification defect. Child was started on LT4 supplementation, follow up after 1 yr, she is doing well & is clinically & biochemically euthyroid. Case-4: 1 month/F born from a preterm twin pregnancy, with first twin being stillborn. The second child exhibited symptoms of hypoglycemia, dyselectrolytemia, along with S-TSH=45.27 µIU/ml, which declined to 15.27 µIU/ml in one week. TS revealed small orthotopic thyroid gland with normal trapping function. Finding correlated well with the follow-up thyroid function tests, suggesting a likely diagnosis of transient hypothyroidism. She is currently off thyroxine, is doing well, and has reached developmental milestones appropriate for her age. Case-5: 5 month/f child presented with features of hypothyroidism, progressive abdominal distension and failure to thrive after a S.TSH>150 uIU/ml. TS revealed absent tracer uptake in the thyroid region suggesting a diagnosis of thyroid agenesis.

Conclusions and References: Early diagnosis and treatment of primary CH are vital to prevent cognitive and physical developmental issues. TS is crucial in diagnosing various forms of CH, including agenesis/dysgenesis/transient hypothyroidism. While TS is an indispensable tool for identifying ectopic/orthotopic functioning thyroid gland and assessing trapping function or organification defects, it has limitations in distinguishing transient from permanent hypothyroidism. Thus, correlating TS results with clinical, ultrasound and laboratory findings is crucial for accurate diagnosis of CH.

Abstract ID: 171: Comparative evaluation of iodine 131 uptake using thyroid uptake probe and gamma camera

S. Vinothini, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of this study was to conduct a comparative evaluation of 24-hour Iodine-131 thyroid uptake between the thyroid uptake probe and gamma camera in patients with thyroid cancer before I 131 treatment. Thyroid cancer post thyroidectomy require I 131 scan and uptake before radioiodine treatment. The measurement of 24-hour thyroid uptake is important for determining the appropriate dosage of Iodine-131. The use of different methods, such as the thyroid uptake probe and gamma camera, can impact the accuracy of these measurements.

Materials and Methods: The study included 10 patients with thyroid disorders who were referred for evaluation before radioiodine treatment. Each patient received 3mCi of Iodine- 131, and 24-hour thyroid uptake was calculated using both the thyroid uptake probe and the gamma camera with high-energy low-resolution collimator. In gamma camera, static view of neck was taken 2 minutes and automatic uptake calculation was done. In thyroid uptake probe, after calibration, counts were measured using standard source and background of the patients were measured, neck counts were measured for 60 seconds.

Results: In the 10 patients with carcinoma of the thyroid, the neck uptake ranged from 0.3% to 1.4% when measured with the thyroid uptake probe, and from 0.3% to 0.9% when measured with the gamma camera. The variation in measurements between the two methods was less than 0.5%. Since we have done for only 10 patients, this study will be concluded with more number of patients in future.

Conclusions and References: The findings of this study suggest that the use of a gamma camera for measuring 24-hour Iodine- 131 thyroid uptake may be an alternative method compared to the thyroid uptake probe. The results showed minimal variation between the two methods, indicating that the gamma camera may also provide accurate measurements for determining the appropriate dosage of Iodine- 131 in patients with thyroid cancers and in deciding resurgery in those patients.

Abstract ID: 191: Role of 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT in patients with medullary thyroid cancer: Insights from a tertiary center experience

Akhil Venugopal, Nishikant Damle, C. S. Bal, Chandrasekaran Ganapathy, Yamini Dharmashaktu, Ritwik Wakankar, G. B. Priyanka, A. R. Vishnu, Preeti Namjoshi, Ravindra Reddy, Viveka Jyotsna, Gopal Puri, Sunil Chumber, Shipra Agarwal

Department of Nuclear Medicine, AIIMS, New Delhi, India

Introduction: MTC is an aggressive form of thyroid malignancy which originates from parafollicular C cells often involving the RET mutations. 75% are sporadic, 25% are familial (MEN 2A, MEN 2B and familial MTC). Both 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT are widely used imaging modalities in evaluation of MTC, however both find limited mention in existing guidelines. In this study, we aimed to determine the efficacy of 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT imaging in patients with MTC and to evaluate the relationship between imaging findings and tumor markers (calcitonin and CEA).

Materials and Methods: We retrospectively reviewed the data of patients with a diagnosis of MTC who underwent either 68Ga-DOTANOC PET/CT or 18F-FDG PET/CT (20 each) in our department from December 2021– August 2024, together with serum calcitonin or carcinoembryogenic antigen measurement within 1 month period. Scan findings of both the imaging modalities were reviewed.

Results: 40 patients (25 females & 15 males, median age 39 years, age ranging 23-67 years) were included in the analysis. 20 patients each underwent 68Ga-DOTANOC PET/CT and FDG PET/CT. 15% (06/40) underwent the scan for baseline evaluation and 85% (34/40) for restaging. 17.5% patients were treatment naive and 82.5% had already undergone total thyroidectomy with or without adjuvant treatments. The overall median values of serum calcitonin level and CEA was 1256 pg/ml (range 18.4-15000 pg/ml) and 125 ng/ml (range 22-703 ng/ml) respectively. In patients who underwent 68Ga-DOTANOC PET/CT the median calcitonin and CEA was 2000 pg/ml (range 18.4-15000 pg/ml) and 48.5 ng/ml (range 12-102 ng/ml) respectively while in patients who underwent FDG PET/CT the median calcitonin and CEA level was 1200 pg/ml (range 34-8902 pg/ml) and 125 ng/ml (range 68-703 pg/ml) respectively. Median calcitonin doubling time (available for 12/40 patients) was 7 months. 68Ga-DOTANOC PET/CT detected primary or residual/recurrent disease in the thyroid bed in 50 % patients (10/20) compared with that of 55% (11/20) for FDG PET/CT.68Ga-DOTANOC PET/CT detected locoregional nodal metastases in 75% patients (15/20) and distant metastases in 40% (8/20) (4 patients with liver, 2 with lung, 2 with skeletal) while FDG PET/CT detected locoregional lymph nodal disease in 90% (18/20) and distant metastases in 45% (9/20) (5 patients with lung, 4 with liver, 3 with skeletal and 1 with pleural). 60% (12/20) patients were having a Krenning score of more than or equal to 3, thus eligible for PRRT.

Conclusions and References: Both 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT are good imaging modalities for assessing disease burden (locoregional and distant metastatic). In our study, the patients with higher calcitonin were frequently evaluated with 68Ga- DOTANOC PET CT, while those with higher CEA were evaluated with 18F-FDG PET CT. 68Ga-DOTANOC PET/CT also helps to identify those individuals eligible for PRRT.

Abstract ID: 26: Potential role of 68Ga FAPI PET/CT in prognostication of cardiac sarcoidosis

Anusha Raju, M. Indirani, S. Shelley

Apollo Hospitals, Chennai, Tamil Nadu, India

Introduction: Cardiac sarcoidosis (CS) is an autoimmune condition marked by granulomatous inflammation of the myocardium, resulting in infiltrative cardiomyopathy. Its varied, non-specific symptoms complicate the diagnosis, making early identification vital due to associated morbidity and mortality. While about 20% of systemic sarcoidosis patients have cardiac involvement, only 5% display clinical symptoms. Traditional diagnostic methods like ECG and echocardiography have limited sensitivity; thus, cardiac MRI and 18F FDG PET-CT are essential for accurate diagnosis. 68Ga FAPI PET/CT has been routinely used in oncological imaging and its uptake in inflammation has been used for interpretation of cardiac remodeling. This study specifically examines the potential role of 68Ga FAPI PET/CT for prognostic evaluation of CS.

Materials and Methods: This prospective observational study took place at our tertiary care center and involved 12 patients, referred by cardiologists, suspected of having CS according to the JCS 2016 criteria. Conducted from November 2023 to August 2024, the study reviewed clinical characteristics, laboratory tests, imaging results, and treatment details. A three-day protocol was followed, starting with rest myocardial perfusion SPECT/CT, then 18F FDG, and 68Ga FAPI PET/CT. After intravenous injection of 122-336 MBq of Ga-68 FAPI, a dedicated cardiac scan was done 45-60 minutes later; with no major dietary restrictions for the FAPI PET/CT. Imaging results from all three scans were compared both visually and quantitatively.

Results: The study included 6 males and 6 females, aged 30 to 77 years, with a mean age of 51 years. Of the 12 participants, 5 patients (41.6%) had both FDG and FAPI uptake, 4 patients (33.3%) had only FDG uptake without FAPI uptake while 3 patients (25.1%) without FDG uptake still demonstrated FAPI uptake. FAPI uptake was more common among patients at advanced stages based on FDG activity grading, and the mean SUV max of 68Ga FAPI increased with higher grades. The mean ejection fraction (EF) and the mean global longitudinal strain (GLS) decreased in the presence of FAPI uptake.

Conclusions and References: FAPI uptake correlated with a higher grade of CS, as well as lower EF and GLS. It effectively detects activated fibroblasts, indicating early-stage myocardial fibrosis, thereby offering valuable insights into the molecular characterization and prognosis of CS. Consequently, FAPI PET/CT plays a crucial role in guiding timely and appropriate management strategies.

Abstract ID: 28: Clinical characteristics and angiography findings in patients undergoing 18F FDG PET/CT myocardial viability and their clinical outcome

T. S. Deepa, Amitabh Arya, Shantanu Pande, Manish Ora

Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: To investigate the clinical characteristics and angiography findings in patients undergoing 18F-FDG PET/CT myocardial viability assessment and their correlation with clinical outcome.

Materials and Methods: A retrospective cohort study was conducted in a tertiary care center with a sample size of 100 patients. Data is collected from 2017 to 2022 who came to nuclear medicine department for cardiac viability scan and clinical outcome of these patients are collected telephonically.

Results: The study included 102 coronary artery disease patients (90 men, 12 women) divided into two groups: Group-A (viable myocardium, 50 patients) and Group-B (scarred myocardium, 52 patients). Both groups had similar age and BMI (Group-A: 59.0±9.3 years, BMI 23.2±2.1 kg/m²; Group-B: 59.7±11.0 years, BMI 24.4±2.2 kg/m²). Group-A had better LVEF (34.8±10.0%) compared to Group-B (32.6±7.1%) with p-value = 0.031. Risk factors such as diabetes, hypertension, and alcoholism were similar. However, smoking was more prevalent in Group-B (67.6%) than in Group-A (32.4%), p-value = 0.011. Angiography revealed that in Group-A, 34.0% had TVD, 40.0% had DVD, 24.0% had SVD, and 2.0% were normal. In Group-B, 23.1% had TVD, 36.5% had DVD, 38.5% had SVD, and 1.9% were normal. Following intervention, in Group-A, 24.0% underwent CABG, 28.0% had PTCA, and 48.0% received OMT. In Group-B, 3.5% underwent CABG, 13.5% had PTCA, and 82.7% received OMT (p-value <0.001). A mean follow-up period of 49.7+/-40.0 months. In group-A, among 12 patients who underwent CABG, 8.3% experienced cardiac death, heart failure rehospitalization, and recurrent chest pain. Of 14 patients who had PTCA, 14.3% had cardiac death and heart failure rehospitalization, and 21.4% had recurrent chest pain. Among 24 OMT patients, 54.2% had cardiac death, 62.5% were rehospitalization for heart failure, and 58.3% had recurrent chest pain (p-values: 0.005, 0.001, 0.005). In Group-B, 2 patients underwent CABG with no cardiac events during follow-up. Among 7 PTCA patients, 42.9% experienced cardiac death and heart failure rehospitalization, and 28.5% had recurrent chest pain. Of the 43 OMT patients, 30.2% had cardiac death and heart failure rehospitalization, and 27.9% had recurrent chest pain (p-values: 0.503, 0.503, 0.681).

Conclusions and References: Patients with viable myocardium determined by 18F FDG PET/CT, experience better survival rates with revascularization compared to those who received only optimal medical therapy (OMT). For patients treated solely with optimal medical therapy, whether they had viable or non-viable myocardium, the clinical outcome in terms of cardiac death, recurrent hospitalization for heart failure and recurrent chest pain were similar.

Abstract ID: 31: Advantages of hybrid MPI SPECT (REST) and 18F-FDG PET/CT for evaluation of cardiac viability

V. Lokesh, E. Venkatachalapathy

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Decisions about revascularization are made based on the assessment of myocardial viability, which is crucial in the management of patients with ischemic heart disease. When assessing myocardial viability and perfusion, conventional imaging techniques might not be as accurate. In order to evaluate the vitality of the heart, this study intends to investigate the benefits of hybrid MPI (REST) SPECT (Single Photon Emission Computed Tomography) and PET/CT (Positron Emission Tomography/Computed Tomography).

Objectives: The primary objective is to compare the efficacy of hybrid imaging techniques in detecting viable myocardium against traditional methods. Secondary objectives include evaluating the impact of these imaging modalities on clinical decision-making and patient outcomes.

Materials and Methods: A cohort study of 10 patients with proven coronary artery disease (CAD) were selected for this study. Each patient underwent both MPI (REST) SPECT and 18F-FDG PET/CT imaging using standardized protocols to evaluate myocardial perfusion and metabolic activity. Data were analyzed to assess the detection rates of viable myocardial tissue and correlate imaging findings with clinical outcomes following revascularization.

Results: results from both scans, and two had positive results from either scan. This comprehensive approach not only improved diagnostic accuracy but also facilitated more informed clinical decision-making. Consequently, a greater proportion of patients experienced successful outcomes after intervention, highlighting the clinical relevance of hybrid imaging.

Conclusions and References: Hybrid MPI (REST) SPECT and 18F-FDG PET/CT represent a significant advancement in the assessment of myocardial viability, offering enhanced diagnostic capabilities and improved patient management. By integrating anatomical and functional data, these advanced imaging modalities allow clinicians to make more precise treatment decisions, ultimately leading to better patient outcomes in ischemic heart disease. Further research is recommended to optimize imaging protocols and evaluate the cost-effectiveness of hybrid approaches in diverse clinical settings, reinforcing their role in contemporary cardiac care.

Abstract ID: 50: Comparison of imaging characteristics of 18F FDG PET and cardiac MRI in patients with suspected cardiac sarcoidosis

Saloni Gadikar, Rohit Bulchandani, H. V. Sunil, Bushra Sadeed

Narayana Hrudayalaya, Bengaluru, Karnataka, India

Introduction: Cardiac sarcoidosis (CS) affects up to 75% of sarcoidosis patients and is responsible for approximately 25% of related fatalities, emphasizing the need for accurate diagnosis. Current guidelines recommend using both 18F FDG PET/CT after Cardiac Magnetic Resonance (CMR) imaging for diagnosis. The recent T2 parameter on MRI and FDG uptake on PET/CT are valuable markers of inflammation, guiding treatment. However, a comprehensive comparison of these two parameters remains understudied. This study will compare the two modalities, focusing on T2 parameter and FDG uptake.

Materials and Methods: 72 patients with suspected cardiac sarcoidosis who underwent both 18F FDG PET CT and cardiac MRI between September 2022 and August 2024 were included.

• 1. A 4 x 4 table was constructed comparing the cardiac MRI imaging parameters:

  • ● Late gadolinium enhancement (LGE) /T1 (present/absent) and

  • ● Myocardial oedema /T2 (present/absent) and 18F FDG PET CT parameters:

    • o Normal

    • o Rest perfusion defect only

    • o FDG uptake only

    • o FDG uptake with perfusion defect.

• 2. All 72 patients were then analysed separately on the basis of MRI and PET imaging characteristics on CS likelihood as

  • ● No CS

  • ● Possible CS

  • ● Probable CS

  • ● Highly probable CS.

Using Chi Square test and Kappa test the likelihoods were compared.

Results: (1) There is a strong and significant correlation between LGE/Raised T1 findings and FDG uptake on PET (P- value - 0.002). However, there was no significant correlation between edema/Raised T2 detected on CMR and FDG uptake (P value - 0.315). (2) There is significant correlation between MRI and PET likelihood in predicting the likelihood of CS (p-value < 0.001). There is strong match with Highly probable CS (77.8%) and weak match with No CS (26.3%). The Kappa statistic is 0.238 indicating the modalities are moderately aligned, but there is still some inconsistency between them.

Conclusions and References: Since there is no significant correlation between the edema/T2 CMR parameter and FDG uptake, it is important to perform both PET and CMR to determine the need to initiate therapy. This study also found that there is weak agreement between the ‘No CS’ likelihood of CS, again indicating the necessity of conducting an FDG PET scan even when MRI results are negative.

Abstract ID: 55: A comparative analysis of Ga-68 DOTANOC PET-CT and F-18 FDG PET-CT in cardiac sarcoidosis: Preliminary observations from a prospective study

Aman Tilak, Chetan Patel, Kh. Bangkim Chandra, Priyanka Gupta, Dikhra Khan, Sambit Sagar, Shubha G. Ravina, Ritwik Nitin Wakankar, Chandrasekaran Ganapathy, Kavin Mathiazhagan, P. Jagatti Krishna, Goriparti Lalitha, C. S. Bal, Sandeep Seth, Sanjeev Kumar, Ambuj Roy, Satyavir Yadav

AIIMS, New Delhi, India

Introduction: Diagnosing cardiac sarcoidosis (CS) remains challenging due to its diverse clinical manifestations and the lack of a definitive diagnostic gold standard. This prospective study presents preliminary findings from an ongoing prospective study comparing Cardiac MRI (CMRI), Ga-68 DOTANOC PET-CT and F-18 FDG PET-CT in patients suspected of having CS.

Materials and Methods: This comparative, prospective study was carried out at the Department of Nuclear Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi. Twenty patients with suspected CS underwent both Ga-68 DOTANOC PET-CT and F-18 FDG PET-CT within a two-week period. F-18 FDG PET-CT scans were performed after standard patient preparation to minimize physiological myocardial uptake. The imaging results were compared to CMRI findings (T1 and T2 mapping & LGE sequences). The patients were screened using revised guidelines (2017) of the Japanese Ministry of Health and Welfare. Two experienced nuclear medicine physicians interpreted the results of all F-18 FDG PET-CT and Ga-68 DOTANOC PET-CT scans in conjunction with each patient’s Tc99m-MIBI SPECT results.

Results: 20 patients (13 males, 7 females) having a mean age of 36.6 ± 8.85 years were included. Out of these, 12 (60%) patients had T2 map and LGE positive/LGE positive on CMRI, and 9 (45%) were positive on F-18 FDG. Both F-18 FDG and CMRI were positive in 8 and both were negative in 3. In the remaining 9 patients, 3 patients were positive on CMRI but negative on F-18 FDG, 1 patient was positive on F-18 FDG but negative on CMRI, while in the other 5 patients the scans could not be interpreted due to physiological uptake of F-18 FDG in the myocardium. Out of the 20 patients, 10 (50%) were positive on Ga-68 DOTANOC. Both Ga-68 DOTANOC and CMRI were positive in 9 and both were negative in 7. In the remaining 4 patients, 3 had CMRI positive but Ga-68 DOTANOC negative, while one had Ga-68 DOTANOC positive and CMRI negative. Thus, the concordance of F-18 FDG and Ga-68 DOTANOC PET-CT with CMRI was in 11/20 (55%) and 16/20 (80%) patients respectively.

Conclusions and References: The result of study demonstrates the potential utility of Ga-68 DOTANOC as an alternative radiotracer to F-18 FDG in diagnosis of CS. No patient preparation is required for Ga-68 DOTANOC unlike F-18 FDG and therefore the issue of equivocal findings due to physiological uptake of F-18 FDG in the myocardium can be addressed.

Abstract ID: 73: Coronary artery disease: A holistic approach to diagnose using myocardial perfusion imaging and CT coronary angiogram

G. Sakthivelayudham, E. Venkatachalapathy, M. Palani, K. Sibu, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Coronary Artery Disease (CAD) is a leading global cause of death, primarily due to atherosclerosis. Early, accurate diagnosis is essential to prevent serious cardiovascular events. While invasive coronary angiography has risks, non-invasive techniques like Myocardial Perfusion Imaging (MPI) and CT Coronary Angiogram (CTCA) offer safer, comprehensive insights. This study suggests combining MPI and CTCA for better CAD detection.

Materials and Methods: A retrospective analysis was conducted on 38 patients with suspected CAD, selected between July 2023 and July 2024. Each patient underwent CTCA for assessing coronary stenosis and MPI using 99mTc-SESTAMIBI to evaluate myocardial perfusion and detect ischemia. The results from both techniques were analysed independently and then combined to offer a detailed assessment of coronary artery disease.

Results: (Refer the table in Abstract document) Of the 38 patients analyzed, 5 of them had single vessel disease, 15 of them had double vessel disease and 18 of them had triple vessel disease. In the patients with single vessel disease 3 patients found to have no perfusion defects with normal function whereas 2 patients had reversible perfusion defect with reduced function. In the patients with double vessel disease 12 patient had no perfusion defect with normal function whereas 1 patient had reversible perfusion defect with normal function and 1 patient had reversible perfusion defect with subnormal function. In the patients with Triple vessel disease 6 patients had no perfusion defects with normal function. 1 patient had no perfusion defect with subnormal function, 3 patients had no perfusion defect with reduced function, 1 patient had reversible perfusion defect with normal function, 2 patient had reversible perfusion defect with subnormal function, 2 patient had reversible perfusion defect with reduced function, 1 patient had irreversible perfusion defect with normal function,1 patient had irreversible perfusion defect with subnormal function,1 patient had irreversible perfusion defect with reduced function.

Conclusions and References: This study demonstrates that integrating CT Coronary Angiogram with Myocardial Perfusion Imaging offers a holistic approach to diagnosing Coronary Artery Disease. The combined use of these modalities enhances diagnostic precision by providing both anatomical and functional insights, leading to better-informed treatment decisions. This method represents a significant advancement in non-invasive cardiovascular diagnosis and has the potential to improve patient management, reduce unnecessary procedures by reassessing the need of surgical interventions, improving medical management, and optimize clinical outcomes.

Abstract ID: 75: A rare case of tuberculous myocarditis

Saloni Gadikar, Rohit Bulchandani, H. V. Sunil, Bushra Sadeed

Narayana Hrudayalaya, Bengaluru, Karnataka, India

Introduction: Cardiovascular involvement of tuberculosis has a very unfavorable prognosis and hence needs an accurate diagnosis. The clinical presentation is also very similar to cardiac sarcoidosis, presenting with ventricular arrhythmias, conduction abnormalities, and heart failure. Although the diagnosis of tuberculous myocarditis requires isolation of MTB by staining or culture in endomyocardial biopsy (EMB), the diagnostic yield is very low; hence, FDG PET/CT and cardiac MR (CMR) are very useful in the diagnosis of inflammatory cardiomyopathies.

Materials and Methods: 36-year-old female presented with complaints of breathlessness and palpitations. On examination, there were bilateral basal crepitations. ECG showed multiple ectopics and short runs of ventricular tachycardia. Echo showed an LVEF of 30%. Coronary angiogram was performed, which showed normal coronaries. CMR features were suspicious of underlying subacute myocarditis/sarcoidosis.

Results: 18F-FDG PET/CT was done, which revealed perfusion defects in the apicoanterior, apicolateral, mid-anterior, mid-anteroseptal, and mid-inferoseptal segments with FDG uptake, suggestive of scar with inflammation. Perfusion defect was seen in the basal inferolateral segment with no FDG uptake, suggestive of scar. FDG uptake was also seen in the right ventricular myocardium. EMB was done, which revealed caseating granulomatous inflammation suggestive of tuberculous myocarditis.

Conclusions and References: This case suggests that TB myocarditis can present as the only manifestation without any extracardiac disease and should also be considered in the differential diagnosis, along with cardiac sarcoidosis, in patients presenting with ventricular tachycardia and heart failure.

Abstract ID: 77: Exploring the practicability of AI chatbots in myocardial viability studies: Can it assist patients in understanding preparation, at-home query resolution and comprehending reports?

Malay Mishra, Sameer Taywade, Rajesh Kumar

Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Artificial intelligence (AI) chatbots have demonstrated their utility through easy accessibility and prompt, comprehensive responses across diverse fields. Their role in medicine has recently been actively investigated. However, the utility of these chatbots in nuclear medicine is yet to be explored. In this study, we evaluated the practicability of AI-driven chatbots in improving the patient experience while undergoing a nuclear myocardial viability study by addressing their queries.

Materials and Methods: We created six different types of nuclear myocardial viability mock reports based on routine scan findings. A set of fourteen questions regarding patient preparation and two questions regarding each of six reports were prepared (twenty-six in total). OpenAI ChatGPT4o (Chat Generative-Pre-trained-Transformer) was accessed between 24/9/24-30/9/24. All preparatory questions and reports with their associated questions were entered in separate chats. Each response was regenerated twice (3 trials/prompt). It was then asked to provide references for the same resulting in 4 responses per prompt. A total of 104 (56 preparation and 48 report) responses were generated and recorded in MS Excel. The responses were analyzed with the help of a customized scale with ratings based on 5 key parameters– appropriateness, helpfulness, empathy, consistency and validity of references with scores 0-2 (0=inappropriate, 1=partly appropriate and 2=appropriate). Each of the 14 preparation & 12 report prompts were evaluated and the scores tabulated. Descriptive statistical analysis was performed for the tabulated data.

Results: The majority of responses were appropriate and helpful for queries related to preparation (21/28, 23/28) and reports (20/24, 24/24). However, empathy and consistency had relatively lower scores in preparation (8/14, 4/14) than report (7/12, 8/12) prompts. Reference validity remained an issue as only one response had a valid reference. Hallucinatory response was noted twice in the responses. None of the prompt responses could have caused harm to the patient if it had been real-life enquiries.

Conclusions and References: AI Chatbots are simple, accessible, safe and handy tools for addressing patients’ queries regarding nuclear myocardial viability studies. They can enhance patient engagement, improve the quality of patient preparation, and aid in the comprehension of nuclear medicine reports. However, its wider application in Nuclear Medicine needs further validation through real-life studies and ongoing refinement of responses using peer-reviewed medical databases, LLMs, and custom-trained GPT models.

Abstract ID: 86: Evaluating the precision of pretest probability and upfront stress myocardial perfusion imaging in diagnosing coronary artery disease

Siddarth Sahu, Sameer Taywade, Rajesh Kumar, Deepanksha Datta

AIIMS, Jodhpur, Rajasthan, India

Introduction: Upfront utility of Stress myocardial perfusion imaging (MPI) in assessment of CAD is still unpopular. In our study MPI was done as a first line evaluation modality in patients with suspected CAD. Analysis was done to evaluate the association of ischemia detection with respect to the pretest probability and final diagnosis of CAD on CAG.

Materials and Methods: A retrospective descriptive study was performed at AIIMS-Jodhpur in patients with suspected CAD who underwent upfront stress-MPI. Pretest probability was calculated based on AHA-score. MPI findings were categorized with respect to different pretest probability subgroups. Coronary territory and degree of ischemia was correlated with CAG.

Results: Total 111-patients underwent upfront Stress MPI. 92/111 patients were negative for stress-induced ischemia and managed conservatively. In 19/111-patients positive for stress-induced ischemia, 4 were low-risk, 10 intermediate-risk and 5 high-risk categories. In low-risk group (4-patients), 2-patients had mild ischemia and 2 had moderate ischemia involving single-vessel territory. Among them, one patient with mild defect had a normal CAG, while another had 60-70% stenosis in single-vessel (D1). Both patients with moderate ischemia on MPI showed SVD (60% RCA and 90% LAD stenosis respectively). In the intermediate-risk group (10-patients), 2/10 patients had mild defects with single-vessel involvement, one with a normal CAG and one with 80% disease in OM1. In 5/10 patients with moderate single-vessel ischemia showed >70% stenosis in corresponding vessels in 4-patients and TVD in 1-patient (LAD 80%, OM3 90% and RCA 90% stenosis). Whereas in 3/10-patients with severe ischemia in two territories on MPI, had >70% stenosis in corresponding vessels in 2-patients while TVD in 1-patient (100% LAD, 60% LCX, 80% RCA occlusion). In the high-risk group (5-patients), 2/5 patients showed mild ischemia involving two-vessel territories both showing >70% stenosis in corresponding vessel on CAD. 1/5 patient with moderate ischemia in two vessel territory revealed TVD (70% LAD, 80% LCX, & 70% stenosis). The remaining 2/5 patients had moderate & severe intensity ischemia with DVD (60% D1 & 70% LCX) and TVD (100% LAD, 80% OM1, 90% RCA) respectively.

Conclusions and References: Stress-MPI depicted ischemia mostly in intermediate and high-risk group. Strength of association of ischemia on MPI with pretest risk categories was most pronounced for intermediate group patients. Ischemia detection on MPI were congruent with CAG. However, weak correlation was seen among number of territories involvement on these two modalities. Thus, this study reiterates the importance of upfront MPI, especially for the intermediate risk population.

Abstract ID: 94: Comparison of normal field of view and extended field of view in obese patients undergoing myocardial perfusion SPECT on CZT camera

Mahima Gupta, Bangkim Chandra Khangembam, Priyanka Gupta, Ritwik Wakankar, Aman Tilak, Chetan Patel

All India Institute of Medical Sciences, Delhi, India

Introduction: The primary objective was to assess the proportion and severity of false positive perfusion defects on myocardial perfusion SPECT (MPS) images obtained using an extended field of view (EFOV) on a cardiac CZT camera in obese patients and compare them to images acquired with a normal field of view (NFOV). Secondary objectives included evaluating any changes in image interpretation and comparing semiquantitative scores and quantitative parameters between the two acquisition methods.

Materials and Methods: Patients aged 18 years or older with clinically suspected or diagnosed coronary artery disease and a body mass index (BMI) ≥ 30 kg/m² who underwent MPS from April 2023 to September 2024 using a dedicated cardiac CZT camera (MyoSPECT) were prospectively enrolled. Stress-rest MPS imaging was performed and interpreted following the American Society of Nuclear Cardiology Guidelines. Each imaging session involved both NFOV and EFOV acquisitions. Perfusion defects corresponding to coronary arteries with >50% luminal stenosis on angiography were considered true positives, while defects with no or ≤50% stenosis were labeled false positives. The proportion and severity of false positive defects were assessed, and semiquantitative scores and quantitative parameters between the two methods were compared using the Wilcoxon signed-rank test. A P value of <0.05 was considered statistically significant.

Results: A total of 21 consecutive patients (7 females, 14 males) with a mean age of 51 ± 9 years and a median BMI of 31.6 kg/m² (range 30.6–60.0 kg/m²) were prospectively enrolled. No false positive perfusion defects were found with either acquisition method. Additionally, no differences in image interpretation were observed between NFOV and EFOV. There were no statistically significant differences in the summed stress scores, summed rest scores, or summed difference scores between the two methods (P ≥ 0.152). However, end-diastolic and end-systolic volumes were higher with EFOV (P ≤ 0.028), but no significant differences were observed in ejection fractions or stroke volumes (P ≥ 0.256).

Conclusions and References: Extended field of view acquisition on a cardiac CZT camera does not provide additional benefits over normal field of view acquisition in obese patients undergoing myocardial perfusion SPECT.

Abstract ID: 100: A distinctive case of ATTR amyloidosis involving the myocardium and thyroid – Diagnosed on 99mTc-PYP imaging and confirmed via biopsy

Manoj Kumar, Harpreet Singh, Ashwani Sood, B. R. Mittal

PGIMER, Chandigarh, India

Introduction: The term amyloidosis encompasses a group of disorders characterized by the abnormal accumulation of insoluble misfolded proteins in the extracellular space, leading to organ dysfunction (RSNA). The deposition of misfolded transthyretin (ATTR) protein results in ATTR amyloidosis, primarily manifesting as cardiomyopathy, peripheral neuropathy, and orbital disease. Amyloid cardiomyopathy is a form of restrictive cardiomyopathy resulting from the accumulation of AL or ATTR fibrils within the myocardium. Distinguishing between the types of cardiac amyloidosis is important for prognosis and guiding treatment strategies. The 99mTc-PYP scan plays a crucial role in the non-invasive identification of ATTR cardiac amyloidosis, owing to its exceptional specificity in detecting this condition hence offering a considerable advantage over echocardiography and cardiac MRI. We hereby report a patient with suspected cardiac amyloidosis, diagnosed on PYP imaging. Furthermore, significant PYP uptake was observed in the enlarged thyroid gland, indicating potential thyroid involvement by ATTR amyloidosis, a finding that was subsequently validated through biopsy.

Materials and Methods: A 36-year-old male presented to the OPD with a one year history of decreased sensations over bilateral lower limbs accompanied by trophic ulcers. Additionally, he had a six-year history of gradual loss of vision in both eyes and was diagnosed with vitreous degeneration. The family history was significant for the notable occurrence of similar vision impairment in two maternal uncles and aunts. Additionally, the patient’s biological brother also had decreased vision along with gastrointestinal symptoms (raising concerns for autonomic neuropathy). The patient’s SERFTs were within normal limits, and the myeloma panel also showed no abnormalities. Nerve conduction studies indicated sensorimotor axonal neuropathy. Given the significant family history s/o autosomal dominant inheritance, familial ATTR amyloidosis was suspected, and the patient was referred for a 99mTc-PYP scan.

Results: The PYP scan revealed increased tracer uptake in the myocardium more than rib uptake indicating a Visual Perugini grade of 3. The Heart to contralateral lung ratio at 1 hour was 2.1. The scan findings were s/o ATTR cardiac amyloidosis. Additionally, the PYP scan revealed diffusely increased tracer uptake in the enlarged thyroid gland, indicating potential thyroid involvement by ATTR amyloidosis.

Conclusions and References: This case report represents the first documented case of potential familial ATTR cardiac amyloidosis in a young male from India. The PYP scan identified the presence of cardiac amyloidosis prior to the emergence of any cardiac symptoms. Furthermore, the scan suggested a rare involvement of the thyroid gland with ATTR amyloidosis, which was subsequently validated through biopsy.

Abstract ID: 103: Comparison of cardiac softwares for the assessment of left ventricular ejection fraction using Tc99m-MIBI on CZT SPECT: Correlation with 2D-echocardiography

P. Jagatti Krishna, Dikhra Khan, Sambit Sagar, Lalitha Goriparti, Aman Tilak, Sivasankar Kanankulam Velliangiri, Chetan D. Patel, Ambuj Roy, Satyavir Yadav, Neeraj Parakh, Sourabh Agstam, Kh. Bangkim Chandra, Priyanka Gupta, P. Balamurugan

All India Institute of Medical Sciences, New Delhi, India

Introduction: Myocardial perfusion SPECT (MPS) is a key diagnostic tool for evaluation of coronary artery disease (CAD). In addition to perfusion abnormalities, this modality also analyzes regional wall motion and calculates quantitative parameter like left ventricular ejection fraction (LVEF). This integrated evaluation of perfusion and LVEF is useful in diagnosis & prognosis of CAD. There are limited number of CZT cameras in our country and lack of standardization and normal database with respect to LVEF values calculated on CZT in Indian population.

Aim: To compare LVEF values using four cardiac quantitative softwares (Emory cardiac toolbox [ECTb], Cedar Sinai, 4D-MSPECT and Myometrix) on Tc99-MIBI MPS acquired on CZT camera with LVEF derived on 2D-Echocardiography (ECHO).

Materials and Methods: This prospective study included 96 patients with known or suspected CAD, referred for MPS and ECHO for their diagnostic work-up. Out of this, 44 patients were suspected to have CAD and 52 patients were known cases. The MPS was processed using vendor provided individual softwares, namely Emory cardiac toolbox (ECTb), Cedar Sinai, 4D-MSPECT and Myometrix. The LVEF was subsequently calculated and compared to ECHO, which was taken as the reference standard. A value of 60% or more on ECHO was considered to be normal.

Results: 96 patients ([80 M, 16 F], median age - 57.5 years) were included in the present study. The mean LVEF on ECHO was 55±8.7%. The mean LVEF values for ECTb, Cedar Sinai, 4D-MSPECT and Myometrix were 59.4±14.7%, 59.6±12.9%, 61.7±12.8% and 54.9±12.6%, respectively. A positive correlation was observed between LVEF values derived by ECHO and MPS software programs: ECTb (r = 0.513, P < 0.001), Cedar Sinai (r = 0.522, P < 0.001), 4D-MSPECT (r = 0.502, P < 0.001) and Myometrix (r = 0.544, P < 0.001). Significant correlation was also seen for LVEFs among the four software programs. Normal cutoff values for LVEF on Emory, Cedar Sinai, 4D-MSPECT and Myometrix were extrapolated to be 58.5%, 58%, 57%, 55.5% respectively.

Conclusions and References: The study highlights a positive correlation for the calculation of LVEF among cardiac softwares when compared with ECHO as well as the normal cutoff values for each of them. The normal cut-off values derived on four quantitative cardiac softwares cannot be used interchangeably which must be taken into context for routine clinical studies.

Abstract ID: 115: Comparative diagnostic accuracy of 18F-FDG-WBC PET/CT and 18F-FDG PET/CT in suspected cardiac infections: A preliminary study

Pareena Malik, Anish Bhattacharya, Harkant Singh, Prashant Panda, Harpreet Singh, Rajender Kumar, Sarika, B. R. Mittal

PGIMER, Chandigarh, India

Introduction: The “2023 Duke-International Society for Cardiovascular Infectious Diseases Criteria for Infective Endocarditis” (Duke-ISCVID IE) Criteria have proposed 18F-FDG PET as a major imaging criterion. 18F-FDG PET/CT requires patient preparation as high protein & fat and low carbohydrate diet for 48-72 hours to suppress physiological FDG uptake. 18F-FDG-labelled-WBC PET/CT circumvents this need and studies have reported higher specificity and positive predictive value. The study aims to compare 18F-FDG-WBC PET/CT with 18F-FDG PET/CT in the diagnostic workup of suspected cardiac infections, particularly in patients where diagnostic dilemma exists i.e. possible but not definite IE and suspected cardiovascular device infection patients.

Aim: To compare the diagnostic yield and accuracy of 18F-FDG-labelled-WBC PET/CT with 18F-FDG PET/CT.

Materials and Methods: Seventeen patients who presented with suspected cardiac infections were recruited. The 2023 Duke-ISCVID IE criteria were used for diagnosis. 18F-FDG PET/CT and 18F-FDG-WBC PET/CT was performed with whole body and dedicated thorax imaging in eight patients after clinical, imaging and laboratory workup. Histopathology or clinical follow up at 4-6 weeks, was done to confirm diagnosis. Duke’s criteria and clinical response were taken as a composite reference standard. Patients who had blood cultures OR ECHO positive AND clinical response positive were taken as true positives.

Results: The mean age of patients was 49 years (14-80 years) of which 2 were female (25%) and 6 were male (75%). The most common symptom was fever, followed by dyspnea. The most common suspected diagnoses were native valve IE (n=1), prosthetic valve IE (n=2), pacemaker infection (n=3), and stent/graft infection (n=2). 18F-FDG-WBC PET/CT and 18F-FDG PET/CT both presented equal sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 83%, 50%, 83%, 50% and 75% respectively. 18F-FDG-WBC PET/CT and showed increased localisation in 6/8 patients (75%) of which 4/8 were IE patients and 4/8 were cardiovascular device infection (CVDI) patients. WBC localisation was observed in three patients who had negative blood cultures.

Conclusions and References: 18F-FDG PET/CT can detect IE and CVDI in patients with good specificity and positive predictive value which is equivalent to 18F-FDG-labelled-WBC PET/CT with the advantage that special patient preparation is avoided and it has no physiological myocardial uptake. It therefore offers a suitable alternative to 18F-FDG PET/CT in cardiac device infection patients. However, since this is an initial experience, further comparison is required to ascertain these findings.

Abstract ID: 117: Comparison of left ventricular function assessed by radionuclide ventriculography using D-SPECT versus conventional gamma camera

Ajay Kumar, Sakshi Chaudhary, Harpreet Singh, Bhagwant Rai Mittal

Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: Planar MUGA evaluates left ventricular ejection fraction (LVEF) using conventional scintillation gamma cameras. Since 2005, dedicated cardiac gamma cameras with CZT detectors offer improved spatial and energy resolution, enhanced sensitivity, faster acquisition, potentially lower radiation doses, and better reproducibility. This present study was aimed at determining whether the LVEF provided by radionuclide ventriculography (RNV) on the CZT detector-based D-SPECT camera is concordant with the LVEF obtained from a conventional NaI (Tl) detector-based gamma camera.

Materials and Methods: This prospective study involved 81 patients who underwent LVEF assessment using both NaI (Tl) and CZT-based (D-SPECT) gamma cameras. Planar and SPECT images were acquired from each system, and LVEF was measured using the multigated acquisition (MUGA) technique. Pearson’s correlation coefficient was used to assess correlation, Bland-Altman analysis evaluated agreement and One way ANOVA with Dunnett’s test was used to determine the difference in mean LVEF derived from different modalities.

Results: A total of 81 patients (58% male, 42% female; mean age: 47.3 ± 14.74 years) were included. The mean LVEF values measured by the different modalities were NaI (Tl)-Planar: 44.52% ± 15.03, NaI (Tl)-SPECT: 52.47% ± 15.51, CZT-Planar: 47.69% ± 15.53, and CZT-SPECT: 52.41% ± 15.52. Pearson’s correlation showed strong to excellent correlation between modalities, with r = 0.911 (p < 0.001) for NaI (Tl)-Planar vs NaI (Tl)-SPECT, r = 0.974 (p < 0.001) for NaI (Tl)-Planar vs CZT-Planar, and r = 0.891 (p < 0.001) for NaI (Tl)-Planar vs CZT-SPECT. Bland-Altman analysis showed better agreement between NaI (Tl)-Planar and CZT-Planar (mean difference: 13.7%) compared to NaI (Tl)-Planar and NaI (Tl)-SPECT (mean difference: 25.36%) and NaI (Tl)-Planar vs CZT-SPECT (mean difference: 28.06%). Both NaI (Tl)-SPECT and CZT-SPECT overestimated LVEF compared to NaI (Tl)-Planar, with NaI (Tl)-SPECT overestimating in 57 patients by an average of 17.85%, and CZT-SPECT overestimating in 52 patients by 17.72%. No statistically significant difference was observed between NaI (Tl)-Planar and CZT-Planar (p = 0.415), while significant differences were found between NaI (Tl)-Planar and both NaI (Tl)-SPECT (p = 0.003) and CZT-SPECT (p = 0.004). Subgroup analysis confirmed these findings in patients with both impaired (≤ 40%) and preserved (>40%) LVEF.

Conclusions and References: CZT-Planar demonstrated excellent correlation and agreement with NaI (Tl)-Planar for measuring LVEF, making them a reliable alternative. CZT camera also offers higher sensitivity, shorter acquisition time, and better image quality, supporting its potential for clinical use in routine LVEF evaluation.

Abstract ID: 122: 18F-FDG PET/CT for diagnosis of infective endocarditis and cardiac prosthesis related infections

Rohit Bulchandani, Saloni Gadikar, H. V. Sunil, Bushra Sadeed

Narayana Hrudayalaya, Bengaluru, Karnataka, India

Introduction: Infective Endocarditis and cardiac device infections present a significant burden on CICUs across the World. Furthermore they come with a significant morbidity and mortality associated with them. Echocardiography is the preferred mode of imaging for the diagnosis of Endocarditis. However in Trans-thoracic and Trans-esophageal echocardiography negative cases, 18F-FDG PET/CT is recommended as an additional modality for ruling in or ruling out the presence of infection. 18F-FDG PET/CT is also useful in identifying systemic manifestations of infective endocarditis and other systemic diseases as the cause of fever in patients negative for cardiac infections.

Materials and Methods: This was a retrospective descriptive study where 20 patients with a clinical suspicion of Infective Endocarditis underwent an 18F-FDG PET/CT Whole Body Scan at our department and their clinical course was followed up. 17 patients were referred for infected prosthetic devices, valves or grafts. 3 were referred for native valve endocarditis.

Results: In the 17 patients referred for suspected prosthesis infection, 12 (70%) patients had findings suggestive of a prosthesis infection. 9 of these PET Positive patients underwent a redo-surgery with prosthesis replacement, of which 6 showed growth on tissue culture of prosthesis. All patients improved post surgery. 3 patients were severely conduit-dependent and could not undergo redo-surgery; they were given antibiotics and discharged when they had a clinical, biochemical and microbiological response to treatment. In the 5 patients with negative PET/CT findings for IE, we were able to identify an alternate cause of infection in 2 patients which included bed sores and pyelonephritis. Antibiotics were discontinued in the 3 patients with PET/CT findings negative for infection. They improved on conservative management. In the 3 patients referred for native valve endocarditis, we found a native valve infection in only 1 patient. However, we concluded the presence of septic emboli in 2 out of the 3 patients, which was of high suspicion of IE.

Conclusions and References: In our study, the sensitivity of 18F-FDG-PET/CT in diagnosis of infected cardiac prostheses was high. 18F-FDG-PET/CT had a high negative predictive value (~100%) in Prosthesis related IE based on the observation that patients that were negative on PET/CT were managed conservatively without the need for re-do surgery. However, 18F-FDG-PET/CT was not a sensitive modality for the detection of native valve endocarditis. 18F-FDG-PET/CT was also able to identify Extra-cardiac manifestations of IE which aids in the diagnosis of the same. Lastly, in febrile patients negative for infective endocarditis, 18F-FDG-PET/CT was able to detect other foci of infections.

Abstract ID: 136: Beyond the echo: 18F-FDG PET/CT in diagnosing cardiac infections – A case series

Vempa Satish, A. V. S. Anil Kumar, M. G. Vishnoi, Nidheesh Kumar, Nithya Anandaram, Archana Yadav

Army Hospital Research and Referral, Delhi, India

Introduction: This study aimed to evaluate the effectiveness of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in diagnosing cardiac infections, including infective endocarditis and periprosthetic infections, in patients presenting with clinical symptoms indicative of infection or fever in cardiac patients with devices.

Materials and Methods: We conducted a prospective study involving ten patients aged 46 to 82 years at a tertiary care center. Each patient exhibited symptoms suggestive of cardiac infections, such as fever, malaise, and new or worsening cardiac murmurs or fever of unknown origin in patients with cardiac devices. Prior to the PET/CT scans, all patients adhered to cardiac infection imaging protocol including high-fat, low-carbohydrate (HFLC) diet to minimize normal myocardial glucose uptake. This dietary preparation is critical for enhancing the sensitivity of 18F-FDG PET/CT by reducing competing glucose metabolism in the heart. Each patient underwent 18F-FDG PET/CT imaging, and the results were analyzed for FDG uptake. Findings were correlated with clinical evaluations to guide management decisions.

Results: Among the ten patients, seven demonstrated significant 18F-FDG uptake in cardiac regions, indicating an infectious origin consistent with their clinical presentations. These positive findings prompted appropriate interventions, including initiation of antibiotic therapy and surgical procedures where indicated. Three patients exhibited no abnormal FDG uptake in the heart, effectively ruling out infective endocarditis and allowing for timely adjustments in their clinical management. This negative result was crucial in redirecting diagnostic efforts. Additionally, one patient (out of three non-infective endocarditis patients) presented with incidental FDG uptake in the parotid gland, leading to further investigation for potential parotid pathologies, such as parotitis or neoplasia.

Conclusions and References: This case series highlights the significant role of 18F-FDG PET/CT in diagnosing cardiac infections, particularly in complex cases involving prosthetic devices where traditional imaging modalities may fall short. The implementation of the HFLC diet was successful in suppressing myocardial glucose uptake, thereby enhancing the diagnostic clarity of the scans. The ability to confirm or exclude infections underscores the value of PET/CT in clinical decision-making. Moreover, incidental findings, such as the uptake in the parotid gland, illustrate the comprehensive diagnostic potential of PET/CT, suggesting the need for further exploration of extracardiac pathologies. Overall, this study advocates for the use of 18F-FDG PET/CT as an essential tool in managing suspected cardiac infections, emphasizing the importance of continued research to optimize its clinical applications.

Abstract ID: 155: Comparison of nonattenuation corrected and attenuation corrected left ventricular ejection fraction from myocardial perfusion SPECT

Gurkirat Singh Nizer, Madan Parmar, Harpreet Singh

PGIMER, Chandigarh, India

Introduction: Due to non-uniform attenuation of the emitted radiation by 99mTc-labeled tracers, it is possible that an attenuation artefact can be introduced (e.g. non-uniform dose distribution). A possibility is that this may result in suboptimal border delineation of the left ventricle, potentially resulting in a lower accuracy for the LVEF assessment using gated SPECT. Therefore, the use of AC gated SPECT should produce accurate LVEF assessments when compared with AC gated non-attenuated (NC) gated SPECT. In the current study, we attempted to investigate if attenuation correction reduces attenuation artefacts by using hybrid SPECT/CT.

Aim and Objective: Evaluation of The Value of The Non-Attenuation Corrected and Attenuation Corrected Ejection Fraction (EF) From Myocardial Perfusion SPECT.

Materials and Methods: A total of 212 patients were included in this retrospective study out of which 145 were males and 67 were females whose Underwent MPI for Perfusion and Viability & whose LVEF are evaluated. Iterative reconstruction methods were used to reconstruct the AC images from the transmission images. The AutoQuant software is used to calculate the left ventricular ejection fraction (LVEF).

Results: In the current study, a total of 212 patients (145 males and 67 females) with ages ranging from 22 to 86 years were included. Depending on the severity of the perfusion defect, the patients were divided into two groups. Patients with no perfusion defect are referred to as “normal patients” & Patients with Abnormal Perfusion are referred as “abnormal patients”. All the patients’ data was evaluated for left ventricular ejection fraction (LVEF) using gated SPECT. A combination of gated SPECT data acquisition, AutoQuant Software, and reconstruction methods was used to obtain NAC (non-attenuation corrected) and AC (attenuation corrected) data for LVEF. The data was expressed as a percentage of the total by assuming a 5 percent change in LVEF as an arbitrary cutoff point. Each AC data point’s LVEF had to be less than 5 percent of the LVEF of the NAC data point for the data to be considered statistically significant. (Data attached in the final abstract word file).

Conclusions and References: According to the findings of this study, attenuation correction significantly improves diagnostic accuracy while also providing greater reliability in the reporting. Using gated SPECT data for quantification of LVEF percent, this study was successful in demonstrating a statistically significant variation in LVEF percent after applying attenuation correction to the data. The study revealed a statistically significant p-value for the normal group of patients.

Abstract ID: 178: Dual Modality imaging in cardiac sarcoidosis: Evaluating diagnostic efficacy of combined (18F) FDG PET/CT and 99mTc-tetrofosmin SPECT/CT in cardiac MRI-identified suspected cases

Mohammad Zain, Mohd Faheem, Manish Ora, Aftab Hasan Nazar, Amitabh Arya, Sanjay Gambhir

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Evaluating Diagnostic Efficacy of Combined (18F) FDG PET/CT and 99mTc-Tetrofosmin SPECT/CT in Cardiac MRI-Identified Suspected Cases.

Materials and Methods: Patient Recruitment and Data Collection: A total of 12 patients with suspected cardiac sarcoidosis on cardiac MRI were enrolled in this study. Data collected included patient demographics (age, sex) and clinical history (symptoms, disease duration and result of Cardiac MRI studies). Imaging Protocol: All patients underwent dual imaging with both (18F) FDG PET and 99mTc-Tetrofosmin SPECT/CT to assess myocardial inflammation and perfusion respectively. 99mTc-tetrofosmin SPECT/CT: First perfusion imaging was done with 99mTc-Tetrofosmin and a SPECT/CT scan is done. (18F) FDG PET/CT: Following the 99mTc-tetrofosmin SPECT/CT, Patient was prepared on high fat-low carbohydrate diet for 3 days. I.V Heparin was given to suppressed normal cardiac activity. Cardiac and whole body FDG PET-CT was acquired in 3-D mode 60 min after intravenous injection of 370 MBq of (18F) FDG using a dedicated LSO PET/CT scanner. Reconstruction of the acquired data was performed to obtain fused PET/CT images in trans-axial, coronal and sagittal views. Images were compared with the perfusion images. Finally results are compared with MRI findings.

Results: Ten of the twelve patients in this study who had suspected cardiac sarcoidosis had considerable (18F) FDG uptake on PET/CT scans, indicating active inflammation in the heart. As demonstrated by two patients who showed metabolic abnormalities without corresponding perfusion deficits, (18F) FDG PET/CT was very useful in identifying inflammation in situations when perfusion imaging alone might not have been sufficient. This disparity implies that, FDG PET/CT can identify inflammation in the early or subclinical phases of a disease, before structural damage or abnormalities in perfusion are noticeable. A thorough picture of disease activity was provided by the dual imaging technique of combining 99mTc-Tetrofosmin SPECT/CT with FDG (18F) FDG PET/CT. This pairing of metabolic and perfusion data could be essential for timely diagnosis and intervention in patients with cardiac sarcoidosis, potentially improving long-term outcomes.

Conclusions and References: The combined use of (18F) FDG PET/CT and 99mTc-Tetrofosmin SPECT/CT demonstrated significant diagnostic utility in identifying myocardial inflammation, especially in early or subclinical cardiac sarcoidosis. This dual imaging approach enhances diagnostic accuracy, with FDG PET/CT effectively detecting inflammatory changes that might precede perfusion abnormalities, emphasizing its value in comprehensive disease assessment.

Abstract ID: 193: Evaluation of left ventricular mechanical dyssynchrony in hypertensive patients with normal gated SPECT MPI: Does it predate left ventricular hypertrophy?

Anshul Arora, Suraj Kumar, Priya Dhingra, Harpreet Singh, Ajay Kumar, Ashwani Sood, Bhagwant Rai Mittal

Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: Left ventricular mechanical dyssynchrony (LVMD) is recognized as a contributing factor to LV dysfunction in hypertensive patients. However, limited studies have examined if LVMD in hypertensive patients predates the development of LVH.

Materials and Methods: This study analyzed data from 121 hypertensive patients with normal left ventricular ejection fraction (LVEF) and gated myocardial perfusion SPECT (GMPS), divided into two sub-groups: those with LVH (n = 50) and those without LVH (n = 71). The control group included 87 normotensive patients with normal LVEF and GMPS. Software-derived phase analysis parameters were compared across groups, and the effects of hypertension and LVH on LVMD were assessed using regression analysis.

Results: The case group (hypertensive) exhibited a higher prevalence of LVMD (33.8%) compared to the control group (18.4%) (p<0.05). Within the case group, the LVH subgroup had a higher prevalence of LVMD (48%) than the non-LVH subgroup (24.3%) (p<0.05) and the control group (p<0.05). No significant difference was found in the frequency of LVMD among the non-LVH subgroup and the control group (p > 0.05). The LVH subgroup also had a greater mean PBW than both the control and non-LVH subgroups, with no significant difference between the latter two. The multivariate analysis for PBW accounted for 17.2% (adjusted R2) of the variance, revealing a significant association with LVH, while hypertension showed no significant relationship.

Conclusions and References: LVMD in hypertensive patients is associated with the presence of LVH. The incidence of LVMD among hypertensive patients without LVH is comparable to that in the normotensive population.

Abstract ID: 29: Multidose formulation and clinical deployment of (90Y) yttrium glass microspheres (Bhabhasphere) in the management of liver cancer in India

K. V. Vimalnath, A. Rajeswari, Sharad P. Lohar, Sudipta Chakraborty

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: Selective internal radiation therapy (SIRT) employing 90Y radionuclide in a suitable form has achieved success in management of unresectable liver carcinoma. Intrinsically radiolabeled (90Y) Yttrium glass microsphere (Therasphere) formulation approved by US FDA for treating primary liver cancer is commercially available at a price not easily affordable by patients in India. An affordable biosimilar product (90Y) Yttria Alumino Silicate (YAS) glass microsphere (‘Bhabhasphere’) is developed and successful bench to bed translation achieved for treatment of liver cancer patients in India.

Materials and Methods: Yttria alumino slilicate (YAS) glass microspheres of composition 40Y2O3-20Al2O3-40SiO2 (w/w) and diameter ranging between 20-36 µm are synthesized and characterized. Intrinsically labeled (90Y) YAS were produced by irradiating 80-100 mg YAS glass microspheres at neutron flux of 1.2×1014 n.cm-2.s-1 for 7 d in Dhruva research reactor. Radioactive glass microspheres were retrieved from quartz ampoule after 24 h post irradiation, suspended in sterile physiological saline, centrifuged and supernatant discarded. (90Y) YAS glass microspheres were reconstituted in 0.6 mL sterile physiological saline, measured in dose calibrator to determine total 90Y radioactivity. Doses of (90Y) YAS glass microspheres were fractionated into sterile glass vials, sealed and autoclaved for 20 min at 121°C and 15 psi pressure. (90Y) YAS glass microsphere formulation was administered through hepatic artery with super selective approach. Fifteen doses of the formulation with 90Y activity ranging from 2.6-7.4 GBq were prepared and clinically utilised.

Results: YAS glass microspheres having high degree of sphericity (>99%) were synthesized with particle size within the range of 20-36 mm. (90Y) YAS glass microspheres were produced with specific activity 140 ± 8 MBq/mg having radionuclide purity 99.91±0.02 % suitable for human clinical applications. Fifteen doses of the formulation were prepared as per clinical requirement and used for treatment of patients with inoperable liver carcinoma. Yttrium-90 PET scans recorded at different time points post-injection showed near-quantitative retention in the injected lobe in liver. Therapeutic doses of (90Y) YAS glass microsphere formulation injected were well tolerated by patients, as no adverse side effect of therapy are reported. Clinical efficacy of the formulation is being investigated.

Conclusions and References: Multidose formulation and deployment of therapeutic doses of (90Y) YAS glass microsphere (BhabhaSphere) in treatment of unresectable liver cancer in India is established. Efforts are underway to ensure wider availability of the formulation in Indian nuclear medicine centres at an affordable cost.

Abstract ID: 92: Functional assessment hepatic perfusion index and comparison with functional liver volume using Tc-99m sulfur colloid SPECT/CT

Sarika S. Prashar, A. Kumar, S. Saini, A. Bhattacharya, B. R. Mittal

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: The hepatic perfusion index (HPI) can be estimated by volumetric liver spleen scan using Tc-99m Sulfur colloid on a single photon emission computed tomography (SPECT)/computed tomography (CT) scanner. Accurate assessment of liver function is essential to effectively manage the patients with non-cirrhotic portal fibrosis (NCPF), liver cirrhosis (LC) and planned for hepatectomy. Thus in this study, the focus was to determine the HPI and correlate it with functional liver volume (FLV) using SPECT/CT.

Materials and Methods: The study was prospectively performed in 34 patients (F 18;M 16) with mean age 35.9 ± 11.3 yrs and NCPF (n=19) and LC (n=15) referred to our department from the department of Hepatology at PGIMER, Chandigarh, for routine liver imaging. Tc-99m sulfur colloid liver scan was acquired 30 minutes after intravenous administration of 3.09 ± 0.71 mCi of radiotracer. SPECT of the liver spleen was obtained in 64x64 matrix (32 views) on a dual head SPECT/CT system (Symbia-T16, Siemens, Germany) with low energy high resolution collimator and CT (100 mA, 120 KVp). Images were reconstructed using Flash-3D algorithm. Reconstructed images were analyzed using 3D volumetric analysis software. Regions of interest were drawn on the trans-axial slices using a fixed threshold (40%) iso-contouring method to calculate functional liver volume. The HPI was calculated as the mean of liver to bone marrow index and liver/spleen index. Percentage quantitative liver uptake was also calculated. The data was tabulated and analyzed using SPSS software, IBM corp. version 25 with statistical significance of p value < 0.01.

Results: The liver showed adequate homogenous tracer uptake in NCPF and impaired heterogenous tracer uptake in LC patients. Analysis of SPECT FLV between NCPF and LC patients demonstrated a statistically insignificant difference (p= 0.288). A statistically significant difference (p= 0.007) was obtained between HPI of NCPF and LC patients.

Conclusions and References: Our findings highlight the potential of Tc-99m sulfur colloid SPECT/CT to diagnose and monitor FLV and HPI in different disease conditions, with distinct differences in HPI observed in these groups. This non-invasive approach could aid in treatment planning and assessing disease progression, particularly in cirrhotic patients where the amount of functioning tissue may be precisely estimated.

Abstract ID: 124: Rhenium-188 microspheres: A revolutionary approach to liver cancer – In vitro investigations

Aarti Aggarwal, Gurjeet Kaur, Ravjit Singh Jassal, Bikash Medhi, Arnab Pal, Bhagwant Rai Mittal, Jaya Shukla

Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: Microspheres carrying radionuclides selectively kill cancer cells while sparing normal cells. This study examined the uptake and retention of 188Re-labeled microspheres in liver cancer cell lines, showing increased cytotoxicity and apoptosis compared to 188Re alone, even after 10 half-lives.

Materials and Methods: The indigenous microspheres have been prepared. These microspheres were labelled with FITC first to study the uptake in liver cancer cell lines (HepG2). The quantification of FITC labelled microspheres was done by flow cytometry and analysed by Flow Cytometry Software. The 3D image z-stacks of fixed cells were generated as the Z-stack function of confocal microscopy. The generated optical sections were used to quantify the intensities. The uptake of fluorescent microspheres was quantified using software and the time point for uptake of cold microspheres was observed. Apoptosis and Cytotoxicity with 188Re microspheres and 188Re alone was performed using Annexin V-FITC apoptosis detection kit and MTT assay. The dose determination was based on the mass of the monolayer formed by the seeded cells. Induction of cell death was measured using a flow cytometer and analyzed by Flow Cytometry Software.

Results: Successful FITC tagging on microspheres was confirmed by flow cytometry. No leaching was observed during the study period of 24 h. Confocal microscopy showed uptake in HepG2 cells at 6 h, with retention in cancer cells. Cytotoxicity assay (MTT) demonstrated dose- and time-dependent responses, with decreased cell viability (77.81% ± 0.015 to 42.03% ± 0.148) over 10 half-lives of 188Re. Flow cytometry analysis revealed reduced viable cells with increasing dose and duration. 188Re labelled microspheres showed continuous viability decrease (51% ± 1.045 to 36.5% ± 0.020) and increased early apoptosis (60.59% ± 0.030) compared to 188Re alone. Late apoptosis and necrosis were minimal. These findings indicate better retention of particulate 188Re liver cancer cells, and delayed response to radiation exposure.

Conclusions and References: Six hours was found to be the minimum uptake time required by microspheres to get accumulated in cancer cells. 188Re labelled microspheres showed better cytotoxicity as compared to 188Re alone. 188Re labelled microspheres behaved as permanent radiation source and delivered continuous radiation exposure for a sufficient time.

Abstract ID: 129: Correlation of liver function tests and tumor markers with the future liver remnant assessment using 99mTc-mebrofenin hepatobiliary scintigraphy in hepatocellular carcinoma

G. Harinee, Vasanth Madivanane, Anirudh Abu Srinivasan, Nishaant Ramasamy, Kabilash Dayalan, Madhusudhanan Ponnusamy

JIPMER, Puducherry, India

Introduction: The main curative treatment for hepatocellular carcinoma is surgical liver resection and transplantation. The extent of liver resection mainly depends on estimated future remnant liver (FRL) function which may be compromised in liver disease. Insufficient FRL will increase the risk of posthepatectomy liver failure (PHLF) which is associated with high mortality. Preoperative estimation of FRL before major liver surgery is proven to help in deciding between for upfront and staged surgery. For this purpose Technetium-99m mebrofenin hepatobiliary scintigraphy (HBS) in combination with single-photon emission computed tomography/computed tomography (SPECT/CT) is applied. In this study we try to explore the pretest probability of FLR with blood parameters including liver function tests and tumor markers. Thus it would help in risk stratification of patients before undergoing FRL as well as transplantation.

Materials and Methods: Retrospectively 25 patients with diagnosed Hepatocellular carcinoma who had undergone preoperative Tc-99m Mebrofenin FRL assessment were included in our study during the period of May 2022 to May 2024. The following procedure was followed for all those patients. Appropriate dose of Tc-99m Mebrofenin was injected intravenously followed by the acquisition of dynamic 1, SPECT/CT and dynamic 2. Images were acquired on Symbia T6 gamma camera and processed on Symbia.Net workstation. Dynamic 1 was used to assess the hepatic uptake and Dynamic 2 was used to assess the biliary excretion. Region of interest was drawn for blood pool, total liver and remnant liver and normalized extraction fraction of total liver and FRL was calculated. The liver function test parameters during the time of scan were collected including Total bilirubin, AST, ALT, ALP and GGT and tumor marker AFP and were correlated with the FRL percentage.

Results: For the 25 patients in our study, Total Bilirubin has a negative correlation with FRL percentage with statistically significant p value (p<0.05). The other LFT parameters such as transaminases, ALP & GGT show strong negative correlation but the p value is not statistically significant. The tumor marker alpha fetoprotein (AFP) shows weak positive correlation, whereas the p value is not significant, resulting in equivocal correlation with FRL.

Conclusions and References: This study has shown strong negative correlation of total bilirubin with FRL percentage which indicates that total bilirubin strongly helps in assessing the pretest probability of FRL and helps in the risk stratification of patients before the Tc99m Mebrofenin scintigraphy. AFP shows equivocal correlation, the reason could be the limited sample size in our study. Thus, in our attempt to add further knowledge to the literature we conclude that the value of Total bilirubin can be included in the risk stratification and thus in the selection criteria for FRL scintigraphic studies in the future.

Abstract ID: 211: To access the incremental value of early dynamic 18F-FDG PET/CT in lesion detection in HCC

Anshul Arora, Raza Abbas Mahdi, Harmandeep Singh, Rajender Kumar, Bhagwant Rai Mittal

Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: F-18 FDG PET/CT has limited sensitivity in the diagnosis of HCC due to high glucose-6-phosphatase levels, low expression of GLUT receptors and high expression of multidrug resistance proteins. Early Dynamic PET imaging (EDPI) can provide perfusion images which can detect hyper-vascularization in HCC, like the arterial phase of TPCT, which is especially beneficial in patients with deranged renal function who cannot be given contrast.

Aim: To assess the incremental value of early dynamic 18F-FDG PET/CT in lesion detection in HCC.

Materials and Methods: Patients with TPCT-confirmed HCC underwent both dynamic perfusion and routine delayed whole-body 18F-FDG PET/CT in the same setting. A low-dose CT of liver (120 kV, 20 mA) was performed, followed by 5-minute dynamic PET acquisition with on-table FDG administration. EDPI were processed in 4 frames of 15 seconds and 4 frames of 1 minute each. The PET images were reviewed by two expert nuclear medicine physicians. Uptake higher than the liver background was taken positive both in the early dynamic and delayed images. The number of lesions detected on the EDPI and the delayed phase were compared with TPCT. Time activity curves (TACs) were generated of regions of interest (ROI) drawn on areas on EDPI showing higher than background uptake corresponding to the lesions seen on TPCT. Additionally, TACs of ROIs drawn on the normal liver parenchyma were also drawn. Percentage washout of the lesions and normal liver parenchyma were calculated. ROC (receiver operating characteristic) analysis was done to find a cutoff for percentage washout between the lesions and the normal liver parenchyma.

Results: Ten patients (mean age 60.2 years, range 28-75 years) were prospectively recruited. The total number of lesions detected in TPCT, EDPI, and delayed PET/CT were 22, 17, and 13, respectively. The sensitivity of delayed PET in detecting was 59.1% (13/22) and EDPI was 77.2% (17/22). Lesions in 8/10 patients were detected on delayed PET/CT, while EDPI detected lesion in all 10 patients. Using 37.2% as a cutoff for washout, the sensitivity and specificity for lesion detection were 81.3% and 90%, respectively.

Conclusions and References: EDPI demonstrated superior detection capabilities compared to delayed PET/CT in HCC evaluation. Hence, EDPI can be used to increase the sensitivity of lesion detection on 18F-FDG PET/CT in HCC in the same setting while performing whole body imaging. Further studies with bigger cohorts and comparing different liver pathologies are required to further solidify its utility.

Abstract ID: 216: Dosimetry, safety profile and response assessment of 188Re-N-DEDC/lipiodol in inoperable hepatocellular carcinoma – A prospective study

Naresh Kumar, Shamim Ahmed Shamim, G. Shivanand¹, Shalimar², Priyanka Gupta, Parul Thakral³, Ishita B. Sen³

Departments of Nuclear Medicine, ¹Radiodiagnosis and ²Gastroenterology and Human Nutrition, AIIMS, New Delhi, ³Department of Nuclear Medicine, FMRI, Gurgaon, Haryana, India

Introduction: 188Re-N-DEDC lipiodol is an emerging Tran-arterial Radioembolization (TARE) agent due to comparable β-energy (Eβmax 2.1 MeV) and penetration range (~11 mm) of 188Re to 90Y. Indigenously developed TARE agent DEDC (Diethyl-dithiocarbamato) by BARC, Mumbai, labelled with 188Re in lipiodol phase has advantage of simple and on-site labelling procedure, cost-effectiveness. Present study is aimed to assess the post-therapy dosimetry, toxicity profile and response to 188Re-N-DEDC lipiodol TARE for the treatment of intermediate and/or advanced HCC.

Materials and Methods: Radiologically and biochemically confirmed HCC patients with/without PVT having ECOG performance status ≤2 and Child Pugh score A/B were recruited. The dosimetrically estimated activity using partition Model for 188Re-N-DEDC lipiodol was administered trans-arterially under fluoroscopic guidance through femoral branch in super-selective artery of tumor. Further, the post-therapy dosimetry was performed using Hybrid Dosimetry Module™. Response was assessed in 26/45 patients initially at 2 months post-therapy by mRECIST criteria and S. AFP level. The clinical & laboratory toxicities were graded by CTCAE v5.0.

Results: Forty-five (45) patients (41 male; 4 female), mean age 57.5 ± 10.61 years were recruited for this study. The median overall injected activity was 5345.8 MBq (IQR= 3669 MBq) based on tumor size using pre-therapy dosimetric calculations. The median prescribed absorbed dose to tumor by partition model was 72 Gy (IQR = 53 Gy). However, the median absorbed dose to tumor was 75.4 Gy (IQR = 54.21 Gy) based on post-therapy dosimetry estimation by Hybrid Dosimetry Module™. Wilcoxon signed-rank test showed non-significant difference between the median values of prescribed and post-therapy estimated absorbed dose to tumor (p-value = 0.7289). Of 26 patients, 5 patients had complete or nearly complete response, 8 patients had partial response, 8 had stable disease while 5 had disease progression on radiological findings. Biochemically, 5 patients had complete response and 10 showed partial response, 8 had stable disease while 6 had disease progression. All patients were available for toxicity evaluation. Abdominal pain was noted in 24/45 (53.3%) patients, nausea and vomiting observed in 3/45 (6.7%) patients; fever was seen in 8/45 (17.8%) patients. All clinical events were transient, grade 2 or less (CTCAEv5.0) and patients improved with symptomatic management. No significant laboratory toxicity was seen at 2 week and 2 months follow-up except significant fall in albumin at 2 weeks. None of the patient had any pulmonary toxicity, myelosuppression or any other long-term toxicity.

Conclusions and References: TARE with 188Re-N-DEDC/lipiodol shows good response with very few short-term toxicities in intermediate/advanced HCC patients.

Abstract ID: 220: Correlation of liver function tests and tumor markers with the future liver remnant assessment using 99mTc-mebrofenin hepatobiliary scintigraphy in hepatocellular carcinoma

Harinee Ganesan, Vasanth Madivanane, Anirudh Abu Srinivasan, Nishaant Ramasamy, Kabilash Dayalan, Madhusudhanan Ponnusamy

JIPMER, Puducherry, India

Introduction: The main curative treatment for hepatocellular carcinoma (HCC) is surgical liver resection & transplantation. Liver resection depends on estimated future remnant liver (FRL) function that’s compromised in liver disease with higher posthepatectomy liver failure. Preoperative estimation of FRL helps in deciding treatment. Thus Technetium-99m mebrofenin scan with SPECT/CT is applied. In this study we try to explore the pretest probability of FLR with blood parameters including liver function tests and tumor markers. Thus it would help in risk stratification of patients before undergoing FRL as well as transplantation.

Materials and Methods: Retrospectively 25 patients with diagnosed HCC who had undergone preoperative Tc-99m Mebrofenin FRL assessment were included in our study during the period of May 2022-May 2024. The following procedure was followed for all those patients. Appropriate dose of Tc-99m Mebrofenin was injected intravenously followed by the acquisition of dynamic 1, SPECT/CT and dynamic 2. Images were acquired on Symbia T6 gamma camera and processed on Symbia.Net workstation. Dynamic 1 was used to assess the hepatic uptake and Dynamic 2 was used to assess the biliary excretion. Region of interest was drawn for blood pool, total liver and remnant liver and normalized extraction fraction of total liver and FRL was calculated. The liver function test parameters during the time of scan were collected including Total bilirubin, AST, ALT, ALP and GGT and tumor marker AFP and were correlated with the FRL percentage.

Results: For the 25 patients in our study, Total Bilirubin has a negative correlation with FRL percentage with statistically significant p value (p<0.05). The other LFT parameters such as transaminases, ALP & GGT show strong negative correlation but the p value is not statistically significant. The tumor marker alpha fetoprotein (AFP) shows weak positive correlation, whereas the p value is not significant, resulting in equivocal correlation with FRL.

Conclusions and References: This study has shown strong negative correlation of total bilirubin with FRL percentage which indicates that total bilirubin strongly helps in assessing the pretest probability of FRL and helps in the risk stratification of patients before the Tc99m Mebrofenin scintigraphy. AFP shows equivocal correlation, the reason could be the limited sample size in our study. Thus, in our attempt to add further knowledge to the literature we conclude that the value of Total bilirubin can be included in the risk stratification and thus in the selection criteria for FRL scintigraphic studies in the future.

Abstract ID: 222: Head to head comparison between F-18 FDG and Ga-68 FAPI PET/CT scan in diagnosing and staging of cholangiocarcinomas

Medha Dutta, Suneetha Batchu, Mohan Roop Jayanthi

AIG Hospitals, Hyderabad, Telangana, India

Introduction: Cholangiocarcinoma (CCA) is a cancer originating from bile duct. There are three types of CCA, namely Intrahepatic, Perihilar (hilar) aka Klatskin tumor and Distal CCA. Perihilar and Distal CCA are together called Extrahepatic CCA. It’s a rare but aggressive tumor. Cholangiocarcinoma is typically incurable at diagnosis, therefore early detection is crucial. Currently used F-18 FDG PET/CT is seen to have sub- satisfactory diagnostic efficacy. Thus, at our institute, we have compared F-18 Fluorodeoxyglucose (FDG) to Ga-68 Fibroblast Activation Protein Inhibitor (FAPI) PET/CT in diagnosing and staging of CCA in 107 patients in conjunction with conventional measures. FDG being the workhorse tracer in Nuclear medicine, works by imaging the higher uptake of radiolabeled glucose by cancer cells due to higher metabolic activity. Whereas, FAPI targets FAP that are widely expressed in the CCA tumor environment, thereby improving diagnostic accuracy.

Aims and Objectives: This is a prospective observational study to compare the role of 18F-FDG and Ga-68 FAPI PET/CT in evaluation of CCA in a single center tertiary level hospital. The study aims to compare Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and Diagnostic Accuracy of both the radio tracers to allow early detection and improved outcomes.

Materials and Methods: Patients were scanned with 18F-FDG and Ga-68 FAPI from head to mid thigh using Siemens Biograph 16 scanner (Siemens, Germany) for 2 consecutive days. Before F-18 FDG PET/CT study day, patients were instructed to fast for 6-8 hours and blood glucose levels were measured before injection. No anti-diabetic medications were to be taken on the day of study, with recent Serum Creatinine within normal limits. Patients were scanned only if their Fasting Blood Sugar (FBS) were between 90-200 mg/dl. For Ga-68 FAPI PET/CT no special dietary restrictions were followed. All studies were reviewed by two expert Nuclear Medicine physicians, enabling increase in diagnostic accuracy and reducing inter-observer variability.

Results: The data of 107 patients of biopsy proven CCA were analyzed. When compared between F-18 FDG versus (v/s) Ga-68 FAPI PET/CT, following values were obtained - Sensitivity of 57% v/s 92%, Specificity of 46% v/s 22%, Positive Predictive Value (PPV) of 78% v/s 80%, Negative Predictive Value (NPV) of 24% v/s 45% and Diagnostic Accuracy of 54% v/s 77% in diagnosing primary tumor.

Conclusions and References: Thus, when compared to F-18 FDG PET/CT, Ga-68 labeled FAPI is a more sensitive radiotracer to diagnose and stage primary cholangiocarcinomas, with higher diagnostic accuracy; thereby helping in proper management of individual cases.

Abstract ID: 42: Role of 99M-TC pertechnetate in Meckel’s diverticulam

K. Archana, E. Venkatachalapathy

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Meckel’s diverticulum, a common congenital anomaly of the gastrointestinal tract, occurs in approximately 2% of the population. It often remains asymptomatic but can lead to complications such as gastrointestinal bleeding, obstruction, and diverticulitis. Diagnosis can be challenging, particularly in pediatric patients, where clinical presentations may mimic other conditions. The use of 99mTc pertechnetate scintigraphy has emerged as a pivotal diagnostic tool for detecting ectopic gastric mucosa, which is present in about half of cases of Meckel’s diverticulum.

Aim: This study aims to assess the diagnostic accuracy of 99mTc pertechnetate scintigraphy in identifying Meckel’s diverticulum, particularly focusing on its ability to reveal the presence of ectopic gastric mucosa, which is crucial for definitive diagnosis and treatment planning.

Materials and Methods: 99mTC pertechnetate scan involves the administration of 99mTC pertechnetate, a radiopharmaceutical agent that selectively localizes in ectopic gastric mucosa. Dynamic imaging was performed immediately after injection, followed by static images at regular intervals. Clinical data, imaging results, and subsequent surgical findings or clinical outcomes were collected.

Results: A total of 10 patients were included in the analysis. The scintigraphy results indicated that 6 patients had positive findings consistent with Meckel’s diverticulum, correlating with surgical Or clinical diagnosis. Symptoms might suggest the presence of Meckel’s diverticulum could be due to other conditions, such as Appendicitis, Inflammatory bowel disease, Intestinal obstruction. In the absence of Meckel’sdiverticulum, imaging studies may show normal bowel anatomy or identify other pathologies. In cases of ectopic gastric mucosa, the detection rate increased significantly, enhancing diagnostic confidence.

Conclusions and References: 99mTc pertechnetate scintigraphy is a reliable, non-invasive diagnostic modality for Meckel’s diverticulum, particularly in pediatric populations where differential diagnoses are critical. Early and accurate diagnosis through scintigraphy can facilitate timely surgical intervention, thereby reducing morbidity associated with complications like hemorrhage or obstruction delayed diagnosis. Overall, diverticulum the results emphasize that 99m TC pertechnetate scintigraphy is a critical diagnostic tool in the evaluation of Meckel’s diverticulum.

Abstract ID: 47: Utility of 18F-FDG PET-CT derived semiquantitative parameters to distinguish gall bladder cancer versus cholecystitis

Ashique Rahman, Girish Kumar Parida, Kanhaiyalal Agrawal, Bramhadatta Pattnaik, Sai Sradha Patro, Kishan Subudhi, Parneet Singh, Tejasvini Singhal

All India Institute of Medical Sciences, Bhubaneswar, Odisha, India

Introduction: Gall bladder cancer (GBCa) is an aggressive malignancy accounting for ~80-95% of biliary-tract malignancies. It carries poor prognosis with median-survival of 5 months. However, its diagnosis can be challenging and is often confused with cholecystitis. Neither clinical symptoms, laboratory tests, nor conventional radiological techniques offer a reliable method for differential diagnosis. We investigated utility of 18F-FDG PET-CT derived semiquantitative parameters to distinguish GBCa from cholecystitis.

Materials and Methods: Patients with suspected GBCa who underwent 18F-FDG PET-CECT imaging were included in the study. Semiquantitative parameters like SUVmax, TLG and MTV were assessed. Univariate analysis was applied to each semiquantitative parameter and area under curve (AUC) of receiver operator curve (ROC) was evaluated and p-value computed by Mann-Whitney-U test. p-value <0.05 was considered significant. Histopathological examination (HPE) was taken as the gold standard. Statistical metrics such as sensitivity, specificity, and accuracy were evaluated to define the efficacy of 18F-FDG PET-CT to distinguish GBCa from cholecystitis.

Results: The study included 41 GBCa patients (14 males, median age-57, range: 35-76 years). Among these, 35 patients had GBCa and 6 had cholecystitis on final HPE. The SUVmax and TLG were significantly different in two groups while MTV was not. Receiver operating characteristic (ROC) curve analyses revealed AUC for SUVmax and TLG of 0.757 (CI:0.596-0.919, p-value:0.046) and 0.767 (CI:0.616-0.920, p-value:0.039). For diagnosis of GBCa a cut-off value of >6.5 for SUVmax (sensitivity and specificity of 71.4% and 83.3% respectively) and >94.8 TLG (sensitivity and specificity of 68.6% and 83.3% respectively) were found to be pertinent.

Conclusions and References: 18F FDG PET-CT derived semiquantitative parameters can effectively differentiate GBCa from cholecystitis.

Abstract ID: 93: Missed large ileal duplication cyst on multiple radiological scans unveiled by 99mTc-pertechnetate scintigraphy

Dhananjaya Saraswat, Pareena Malik, Amisha Jamwal, Suraj Kumar, Anish Bhattacharya, Bhagwant Rai Mittal

PGIMER, Chandigarh, India

Introduction: An eight year old boy suffering from abdominal pain and intermittent episodes of melena since 7 years. Multiple ultrasonography and CT scans done throughout the years were unremarkable. The child was now referred for 99mTc-pertechnetate scan to exclude the presence of ectopic gastric mucosa which unraveled the possibility of extrinsic gastric mucosa or duplication cyst. Subsequently the child underwent surgery to remove a 30 centimeters duplication cyst. Histopathological examination unveiled the presence of gastric mucosa. This article emphasizes the importance of pertechnetate scintigraphy over conventional radiological scans, which missed the large duplication cyst, illustrating a significant radiological oversight.

Materials and Methods: This is the case of an eight-year-old boy who presented to the emergency room with severe abdominal pain. Upon admission, his hemoglobin level was 6 g/dL, and ultrasonography (USG) revealed a severe intra-abdominal bleed. Drains were placed, resulting in symptomatic improvement. However, the child continued to experience episodes of melena. Further inquiry revealed that the child had been suffering from chronic anemia and similar episodes for several years. Despite multiple diagnostic efforts, including multiple ultrasonography and CT scans, no abnormality was detected. A CT enterography was also performed but failed to reveal any pathological findings. The child was referred for a 99mTc-pertechnetate scan to rule out Meckel’s diverticulum as the potential source of bleeding.

Results: The scan demonstrated a linear focus of increased tracer uptake within the small bowel loops, appearing simultaneously with the stomach’s uptake and progressively increasing in intensity. To further localize the site, a hybrid SPECT-CT was performed, which roughly localized the tracer uptake to the ileum. The child underwent open laparotomy, revealing a large, tubular ileal duplication cyst approximately 30 cm in length on the mesenteric side with a perforation at the center of the cyst, located 25 cm proximal to the ileocecal junction. Histopathological examination confirmed the presence of gastric mucosa within the duplication cyst.

Conclusions and References: Enteric duplication cysts (EDCs) are an uncommon type of congenital anomaly with an incidence of 1 in 4500 neonatal autopsies or 1 in 18,000 live births. These may contain heterotopic gastric or pancreatic mucosa. The child underwent seven computed tomography scans and three ultrasonography over the course of many years which failed to demonstrate the etiology. This case emphasizes the diagnostic limitations of conventional radiological imaging in detecting certain duplication cysts, and highlights the superior diagnostic utility of 99mTc-pertechnetate scintigraphy in identifying ectopic gastric mucosa.

Abstract ID: 134: Exploring tumor heterogeneity in esophageal carcinoma using 18F FDG PET/CT imaging

Tanvi Sarwal, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Esophageal carcinoma is a major cause of cancer-related mortality worldwide, with squamous cell carcinoma (SCC) and adenocarcinoma being the two most common histological subtypes. Differentiating between these subtypes is crucial, as they have different prognoses and treatment approaches. Intralesional tumor heterogeneity, which reflects the biological variability within a tumor, can be quantified using the ratio of SUVmax to SUVmean derived from 18F flourodeoxyglucose positron emission tomography/ computed tomography (18F FDG PET/CT) scans. This study aimed to evaluate the role of the tumor heterogeneity in esophageal carcinoma patients.

Materials and Methods: This was a retrospective study of 51 patients of histologically proven eesophageal carcinoma who underwent 18F FDG PET/CT for either staging or response evaluation. The SUVmax and SUVmean of the primary lesion were calculated. Patients were categorised into squamous cell carcinoma and adenocarcinoma esophagus based on the histopathological reports. Additionally, patients were grouped based on the presence or absence of distant metastases. The intralesional tumor heterogeneity index was defined as the ratio of SUVmax to SUVmean. The Mann-Whitney U test was applied to determine statistical significance in two areas: (1) tumor heterogeneity index and histological subtype, (2) tumor heterogeneity index and presence of distant metastases.

Results: The study population comprised of 26 females and 25 males. Out of the 51 patients, 29 were for staging, and 22 were for response evaluation. 25 patients were diagnosed with SCC, and 26 patients with adenocarcinoma. Distant metastases were identified in 28 patients, while 23 patients had no distant metastases. There was a statistically significant difference in the tumor heterogeneity index between patients with well differentiated SCC and those with adenocarcinoma (p value = 0.03). However, no statistically difference in tumor heterogeneity index between patients with distant metastases and those without distant metastases (p value = 0.82). Similarly, there was no statistically significant difference in the tumor heterogeneity index between patients with well-differentiated and poorly differentiated SCC (p = 0.30).

Conclusions and References: The tumor heterogeneity index may be a valuable tool for distinguishing between SCC and adenocarcinoma in esophageal cancer. However, its role in identifying distant metastases or tumor differentiation appears limited. Larger, prospective multi-centric studies are necessary to validate these findings and explore the potential clinical applications of tumor heterogeneity in esophageal carcinoma management.

Abstract ID: 161: Assessment of gastric emptying time using idly as a test meal in South Indian population

M. Vishnuvarthan, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: Aim of the study is to calculate Gastric emptying time using traditional South Indian dish, Idli as a test meal. Radionuclide gastric emptying and motility studies are comprehensive and non-invasive. The counts in the stomach reflect the meal volume at any given time. Gastric emptying studies (GES) assess normal, delayed, or accelerated emptying rates.

Materials and Methods: Equipment -Symbia T-Truepoint SPECT/CT equipped with Syngop workstation. Methodology - Mix 1-2 mCi of Tc-99m sulfur colloid into idli batter in an aluminum cup and steam the mixture for 10 minutes to prepare idlis. Serve at least three idlis, along with sambar, coconut chutney and 120 ml of water was also provided. The meal should be consumed within 10-15 minutes, followed by acquisition of 1 minute scan at 0 (immediately after oral ingestion) and delayed for 1 hour, 2 hour,3 hour and 4 hours. Scan will be done with the matrix size of 128 ×128. Geometrical mean of counts at each time point was calculated Geometrical mean =√(Counts (anterior) × Counts (posterior)).

Results: This study investigates gastric emptying rates in a group of 10 patients using Symbia T-Truepoint SPECT/CT imaging. The result indicates a progressive increase in gastric excretion over time with 31% (normal>10%) of the gastric contents excreted at 1 hour, 61% (normal>40%)at 2 hours, 85% (normal>70%) at 3 hours, 92 % (normal>90%) at 4 hours post-ingestion. The values were similar to observed values in literature.

Conclusions and References: Idli is a low-fat and easily digestible South Indian food. The study concludes that idli is a suitable and effective food choice for gastric emptying studies, particularly in regions where it is culturally accepted. This could enhance the applicability of gastric emptying studies in Local populations.

Abstract ID: 208: Role of 18F FDG PET-CT in patients with intrahepatic cholangiocarcinoma: A retrospective analysis from single centre

G. B. Priyanka, M. Kavin, G. Chandrasekaran, Akhil Venugopal, Damle Nishikant, Tripathi Madhavi, Shamim A. Shamim, Singh Anand, Kataria Kamal

All India Insitute of Medicial Sciences, New Delhi, India

Introduction: Intrahepatic cholangiocarcinoma (ICC) is a primary liver cancer that often presents with metastatic spread at diagnosis. Positron Emission Tomography-Computed Tomography (PET-CT) is widely used in the staging and evaluation of ICC. This study analyses PET-CT findings in a cohort of patients with histologically confirmed ICC, focusing on hepatic and extra-hepatic disease patterns.

Materials and Methods: A retrospective review was conducted on 31 patients with confirmed intrahepatic cholangiocarcinoma who underwent PET-CT scans between April 2017 and September 2024. Patient demographic data, including age and sex, were recorded. PET-CT findings were categorized based on the presence of hepatic lesions (single or multiple liver lesions), lymph node involvement (periportal, portocaval, retroperitoneal), lung lesions, bone lesions, and other extra-hepatic disease sites. CA 19-9- a commonly used tumour marker for ICC was also collected and correlated with the disease burden- localised vs metastases.

Results: Of the total 31 patients- 21/31 were female and 10/31 were male patients. The mean age being 54.2 years (range 30-78 years). Among the 31 patients with ICC, the most common findings included:

• ● Single liver lesions in ~ 19% (6/31 patients),

• ● Multiple liver lesions in 48% (11/31 patients),

• ● Periportal lymph node involvement in 48% (15/31 patients).

Extra-hepatic spread was commonly observed in the form of lymph node involvement, such as:

• ● Retroperitoneal lymph nodes in 51% (16/31 patients),

• ● Supraclavicular lymph nodes in 13% (4/31 patients).

• ● Omental caking and mesenteric streaking in 25% (8/31).

• ● Lung lesions in 30% (9/31 patients).

Bone metastases were rare, occurring in less than 5% (1 patient). Omental caking and mesenteric streaking were observed in 25% (8/31). CA 19-9 levels were available for 20 patients (7 patients with localised disease and 13 with metastatic disease) at the time of the scan. The median CA 19-9 for localised and metastatic diseases was 29.4 and 148.3, respectively. There were higher levels of tumour marker noted in metastatic disease.

Conclusions and References: The PET-CT findings in this cohort of patients with intrahepatic cholangiocarcinoma illustrate the patterns of metastatic spread, with frequent involvement of the lungs and lymph nodes. Bone metastases were less common. These findings reaffirm the utility of PET-CT imaging in the staging and monitoring of ICC.

Abstract ID: 19: Antenatally detected hydronephrotic kidneys equivocal for PUJ obstruction in dynamic Tc99m EC scan: Can delayed scan help to predict the future regarding spontaneous improvement?

Mohammed Hashmatullah

KK Nuclear Scans, Nava Bharat Chambers, Hyderabad, Telangana, India

Introduction: Antenatally detected hydronephrosis is reported to resolve spontaneously on follow up. In this retrospective study, we have tried to see whether information from further delayed scan can have a predictive role regarding spontaneous improvement or otherwise, particularly in those with baseline equivocal drainage pattern.

Materials and Methods: This study group includes 27 children who had undergone Tc99m EC dynamic renal scintigraphy twice during the period 2022 - 2024. Age range = 1 to 24 months, Inclusion criteria: drainage across PUJ moderately prolonged with delayed peak followed by plateau in the renogram curve. Iso-time static images were obtained immediately after the dynamic scan and again after about 60 minutes delay; Quantitative comparison of activity was carried out using decay correction. Images were categorized as either retention or wash out (good or partial).

Results:

Conclusions and References: We found that none of the baseline scan parameters could predict the future outcome regarding spontaneous improvement. Even the presence or absence of delayed washout could not predict spontaneous improvement or otherwise. This highlights the dynamic nature of PUJ in these children requiring sequential scans for follow up.

Abstract ID: 61: The role of DMSA in diagnosing and assessing cortical scarring in paediatric patients with urinary tract infections and vesicourethral reflux

A. Jenifer Saranya, E. Venkatachalapathy, M. Palani, K. Sibu, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Urinary tract infections (UTIs) in children are a significant cause of renal damage, particularly leading to cortical scarring. Vesicourethral reflux (VUR) is a condition which involves the abnormal backflow of the urine from the bladder into the ureters and into the kidneys. Early detection and monitoring of renal scarring are critical for preventing these outcomes. DIMERCAPTO SUCCINIC ACID (DMSA) renal scintigraphy is the gold standard technique for detecting cortical scarring and assessing renal parenchymal damage in paediatric patients with UTIsand VUR.

Aim: (1) To determine the sensitivity and specificity of DMSA scans in detecting cortical scarring. (2) To evaluate the role of DMSA imaging in the long-term management of patients with recurrent UTIs or VUR. (3) To compare DMSA results with other imaging modalities like ultrasoundand CT.

Materials and Methods: This study involved 20 paediatric patients aged 0-16 years assessed for UTIs and VUR. Sample size: 20. DMSA renal scintigraphy was performed to evaluate renal scarring. 20 patients were diagnosed with UTI and VUR. These patients are reviewed for the presence and absence of cortical scarring. Results from DMSA scans were compared with renal Ultrasound and Computed tomography (CT) findings to determine their effectiveness in identifying renal damage.

Results: DMSA scintigraphy detected renal cortical scarring in a larger proportion of patients with recurrent UTIs and VUR. DMSA scan shows high sensitivity and specificity in detecting cortical scarring as compared to Ultrasound and Computed tomography (CT). In children with higher grades of VUR, DMSA scans showed an increased incidence of scarring. Renal ultrasound was less sensitive, often missing early parenchymal damage that was identified by DMSA. DMSA scans also provided valuable information during the acute phase of infection, indicating areas of acute pyelonephritis.

Conclusions and References: DMSA renal scintigraphy is a highly sensitive imaging technique for diagnosing cortical scarring in paediatric patients with UTIs and VUR. Its superiority over ultrasound makes it a critical tool for early detection and long-term assessment of renal damage, especially in high-risk. DMSA scintigraphy is the gold standard for cortical scarring diagnosis in nuclear medicine.

Abstract ID: 83: Role of DTPA scintigraphy in pre- and post-pyeloplasty conditions in paediatric age group

G. Keerthana, E. Venkatachalapathy

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Pyeloplasty is the surgical treatment for PUJ obstruction, a common congenital condition causing hydronephrosis in children. While ultrasound can provide anatomical details, it does not assess renal function or drainage efficiency. The DTPA scan, a nuclear medicine technique, is widely used to evaluate renal function and drainage before and after pyeloplasty. This study examines the role of DTPA scans in assessing the success of pyeloplasty by comparing renal function and drainage parameters before and after surgery.

Materials and Methods: This retrospective study was conducted on 20 paediatric patients who underwent pyeloplasty for PUJ obstruction. DTPA scans were performed on all patients both preoperatively and six months postoperatively. The following parameters were evaluated: split renal function (SRF), glomerular filtration rate (GFR) and time to maximum activity (Tmax) in the affected kidney, as well as the clearance half-time (T½) for drainage efficiency. Improvement in renal function and drainage was considered indicative of a successful pyeloplasty. Statistical analysis was performed to compare pre- and post- pyeloplasty DTPA results.

Results: Preoperative DTPA scans showed decreased SRF, GFR and prolonged T½ in the affected kidney, indicating impaired drainage and function while in postoperative DTPA scans, some showed increased SRF, GFR compared to pre-operative DTPA scans and normalization of T½ values indicating restoration of renal function and drainage while some seemed to remain the same or worsened. The mean difference in pre- and postoperative values was statistically significant.

Conclusions and References: DTPA renal scintigraphy proves to be an essential tool in evaluating the success of pyeloplasty in children with PUJ obstruction. By comparing pre-and post-pyeloplasty results, we can conclude DTPA scans provide objective evidence to confirm the surgical success and guiding postoperative management. Therefore, DTPA scanning is recommended as part of the routine follow-up after pyeloplasty.

Abstract ID: 101: Development and standardisation of lyophilised single component kit for the preparation 99mTc-ethylene dicysteine for renal dynamic function studies

G. Shunmugam, M. Sheela, B. Sanjeev Kumar, R. Krishna Mohan, Vijay Kadwad, Usha Pandey

BRIT, DAE, Navi Mumbai, Maharashtra, India

Introduction: BRIT is currently supplying a three component kit for the preparation of 99mTc-Ethylene dicysteine (EC) used for renal dynamic function studies (Code: TCK-43). BRIT has planned to modify the current three-component kit into a single-component kit as a part of its continuous product development. Hence, the work has been undertaken to standardize a single component kit for the preparation 99mTc-Ethylene Dicysteine.

Materials and Methods: This kit is prepared by combining key ingredients—EC, Mannitol, EDTA, Ascorbic acid, Na2HPO4, NaH2PO4, and reducing agent Stannous chloride in a lyophilized form. The radiolabeling procedure is streamlined to either 20 minutes incubation at room temperature or 10 minutes boiling water bath, significantly reducing the preparation time. Two solvent system paper chromatography using 1 mm Whatman paper with Acetone and Saline as solvents are found to be suitable and easy system to assess the free pertechnetate and Reduced hydrolyzed Technetium (RHT) impurities respectively.

Results: Four consecutive batches were made and Radio Chemical Purity (RCP) was found to be more than 95% in all these batches. In vitro stability of the 99mTc single component EC kit is similar to the current three component EC kit (TCK-43). Work is under progress to study the long term stability of the lyophilized single component kit and its biological efficacy to be confirmed through animal bio-distribution studies.

Conclusions and References: This work focuses on the development of a user-friendly single component kit for the preparation of 99mTc-Ethylene Dicysteine (EC) and promises to optimize both production and clinical application, ultimately benefiting and enhancing the renal dynamic function studies.

Abstract ID: 157: A comparative study of renal diuretic 99mTc EC scintigraphy and ultrasound for diagnosing PUJ obstruction in children

Aman Aboobacker, K. K. Kamaleshwaran, E. Ramkumar. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of this study is to compare diuretic renogram and ultra sounography (USG) in diagnosing pelvic –ureteric junction (PUJO) in children. PUJ obstruction is a common cause of renal impairment and hydronephrosis. Accurate diagnosis is crucial for timely intervention while ultrasound is often the first line imaging modality due to its availability and lack of radiation, renal diuretic scanning offers functional assessment of renal drainage.

Materials and Methods: 20 Patients with suspected PUJ obstruction was enrolled having an average age between (1-5 years). Each patient underwent both diuretic renogram and USG. Diuretic renogram involved the administration of diuretic (furosemide) using F-0 protocol along with Tc-99m EC to assess renal function and drainage. Ultrasound assessed renal size, hydronephrosis and PUJO. Diuretic renogram showed kidney function and drainage. The results were compared against a gold standard of surgical findings or follow up imaging.

Results: In all 20 patients USG suggests of PUJO with average APD (7 mm-3 cm). Among 10 patients APD (<1 cm) DRS showed good function suggestive of non-obstructive PUJ and complete drainage. In other 10 patients with APD (>1 cm) showed decreased kidney function and obstructed PUJ.

Conclusions and References: Renal diuretic scanning is more accurate in diagnosing PUJ obstruction and helps in avoiding surgery in the non-obstructed PUJ.

Abstract ID: 170: To evaluate the glomerular filtration rate in kidney donors by using 99mtc DTPA in older age patient (≥ 60)

Ashvin Avaran, K. K. Kamaleshwaran, E. Ramkumar R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of this study to assess the GFR by using 99mtc DTPA for the patients who have aged 60 or above and also to prove the eligibility for the patients for this age group as a donor for kidney transplantation. Glomerular filtration rate represents the flow of plasma from the glomerulus into the bowman’s space over a specified period. The normal GFR rate for an adult is 80-120 ml/min. 99m Tc- DTPA renogram scan is versatile tool to evaluate the GFR of the kidney. Through the GFR for the patients age 60 or above were also eligible to donate. So, the scan provides non-invasive methods to assess the renal function with appropriate quantification and also accepted values of GFR and helpful for renal transplantation.

Materials and Methods: Equipment -Symbia T-Truepoint SPECT/CT equipped with Syngop workstation. Methodology -99m Tc-DTPA is prepared in-vivo method and injected intravenously. Patient was asked to drink at least 1.5 litres of water just before the scan. Dynamic image was acquired with the matrix size of 64×64, zoom-1 is preferred to obtain good images.

Results: Among 25 patients (15 male & 10 female) aged 60 or above underwent 99mTc DTPA scan. From these data’s the average GFR rate was 88 ml/min was obtained which is considered normal. This finding underscores that a significant proportion of older patients may retain adequate renal function with appreciable and acceptable GFR. So these age group voluntary kidney donors are suitable for donating kidney.

Conclusions and References: This study evaluates the Glomerular filtration rate (GFR) in patients aged 60 and above using DTPA scans to assess their suitability for kidney transplantation revealing an average GFR of 88 ml/min, which falls within the normal range. These findings indicate that a significant number of older patients maintain adequate renal function, suggesting that age alone should not disqualify them from being considered as donors.

Abstract ID: 183: Delayed imaging of (99mTc) Tc-DMSA renal cortical scan in pediatric patients: Improving image quality

Gowtham Kumar, Julie Hepzibah, Saumya Sunny, Prabu Titus

Department of Nuclear Medicine and Molecular Imaging, Christian Medical College, Vellore, Tamil Nadu, India

Introduction: A renal cortical scan is a nuclear medicine imaging procedure used to diagnose renal scarring and pyelonephritis. It can also provide an accurate differential renal function by using [99mTc] Tc-DMSA (Tc99m dimercaptosuccinic acid). The tracer is injected intravenously and after a period of ideally 2-3 hours, a gamma camera captures a static image for 400 kcts. Although practical, this may be challenging in pediatric patients where significant motion during image acquisition may affect image resolution and therefore render images non-diagnostic. To correct motion artefacts in DMSA delayed imaging by acquiring dynamic frames and using motion correction software to align them.

Materials and Methods: A gamma camera fitted with a LEHR collimator an acquisition system SYNGOVIA processing workstation with licensed MOTION CORRECTION software installed. The time of acquisition was calculated by: Time of acquisition (min) = 400 kcts/(count-rate (in kcps)x60). Then, 10 s, 20 s, 30 s frame studies were acquired for the calculated time of acquisition based on the subject’s motion. Lesser time per frame was applied for subjects prone to larger ranges of motion. The movement was corrected using the multi-frame axis alignment software. The resultant motion-corrected frames were then made into a composite image using the series arithmetic operation. Region of interest (ROI) was drawn around the kidneys to estimate the split function. The resultant images were blinded and presented to an NM physician for evaluation.

Results: A total of 10 pediatric patients (6 M/ 4 F, ages ranging from 8 months to - 2 years) who underwent [99mTc] Tc-DMSA scan from 22/07/2024 to 27/09/2024 were included in this study. On comparison of the resultant images acquired by these methods, it was found that the composite image had higher definition of the photon intensities and better resolution. The renal split function was also similar in both methods with deviation of not more than 2%.

Conclusions and References: The frame mode method can provide a higher image quality than static imaging. This may be particularly useful in acquiring delayed images of [99mTc] Tc-DMSA renal cortical scan in pediatric patients where patient motion is a concern.

Abstract ID: 195: Transplant donor data analysis from Tc-99m DTPA scan from a tertiary kidney transplant center

Divya Velusamy, E. Ramkumar, K. K. Kamaleshwaran, E. R. Radhakrishnan, Arunpandiyan, F. R. Kingsley, A. Sowmiya, Ruth Rajasekar, C. Vinoth Kumar, Rithika Rajkumar

Department of Nuclear Medicine and PET/CT, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of this study was to correlate the GFR (estimated with Gate’s protocol) with age, sex and differential kidney function.

Materials and Methods: Retrospective analysis of 333 prospective kidney donors (89 males, 244 females; mean age 48 ± 12 years) who underwent DTPA scans in the year of 2021. Prospective kidney donors required a minimum GFR of 80 mL/min for consideration. Descriptive and inferential statistical methods such as age, sex, renal split function and total & mean GFR were utilized to analyze the data, providing valuable insights into kidney donation trends.

Results: Among 333 prospective renal donors from (21-79) age group, 89 were males and 244 were females. Majority of the total study population 40.2% (134/333) belonged to the (42-51) age group, with 28% (25/89) males and 44.7% (109/244) females. The overall mean GFR from the total population was 87.93 ± 14.48 mL/min & overall mean GFR from the age group of (42-51) was 88.49 ± 2, Notably, 1.5% (5/333) of female donors in the age range of (60-65 years) exhibited GFR values below 80 mL/min.

Conclusions and References: This study reveals that individuals aged 42-51 years constitute the optimal demographic for kidney donation, with females comprising a substantial proportion of potential donors, and emphasizes the crucial role of mean GFR values in guiding donor selection, independent of sex.

Conclusion: This study informs evidence-based practices in kidney donation and transplantation, enabling healthcare professionals to Identify optimal donor demographics, refine GFR estimation protocols, enhance patient outcomes through informed donor selection.

Abstract ID: 205: Comparison of gamma camera quantification versus visual assessment of images in renal scintigraphy in patients diagnosed with pelvi-ureteric obstruction

Eva Leonie, Julie Hephzibah, Saumya Sara Sunny, Hanna Johnson, Prabu Titus

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Renal scintigraphy is a reliable diagnostic tool in pelvi-ureteric obstruction (PUJO). Following IV injection of Tc99m EC (Ethylene Dicysteine) time activity curve is generated to assess drainage of tracer. Visual interpretation, split function of kidneys, and software-generated clearance values have been used to assess the status of obstruction. However there may be discordances between visual assessment and clinical outcome. Hence this study was designed to assess the additional utility of quantification.

Aim: To compare Gamma camera-based quantitative analysis with visual assessment of drainage in patients with PUJO.

Materials and Methods: Scintigraphic data of 18 patients with unilateral PUJO were analysed. Following IV injection of Tc99m –EC (120 MBq) dynamic images, Post Void (25 min), and Delayed images (2-3 hours) were acquired with Gamma camera. Inj. Lasix (40 mg) was injected at 10 min into the study (F+10). ROIs (region of interest) were drawn around both kidneys in post-void and decay corrected delayed images. The percentage retention of tracer in the affected kidney in the delayed image was calculated by the formula: Post void counts / Delayed Image counts x 100.

Results: Eighteen patients (16 M, 2 F; Age Range of 16-56 y) were included in the study. They were reported as obstructed drainage, low grade obstruction and slow patent drainage respectively through visual interpretation.

Conclusions and References: The quantitative analysis correlates with the visually analyzed impression. Quantitative analysis can also be used as a reliable analytic method in our daily practice, especially when there is a discordance in differentiating a slow-draining system from an obstructed one.

Abstract ID: 39: Role of 99mTC-MDP BONE scintigraphy in Paget’s disease

K. G. Naageswari

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Paget’s disease of bone is a chronic disorder characterized by abnormal bone remodelling, leading to enlarged and weakened bones. Technetium-99m-MDP (99mTc-MDP) bone scintigraphy play a crucial role in the diagnosis of this condition by highlighting areas of increased osteoblastic activity. This study aims to evaluate the utility of 99mTc-MDP bone scintigraphy in the diagnosis, assessment, and monitoring of Paget’s disease.

Materials and Methods: A retrospective analysis was conducted on patients suspected or diagnosed with Paget’s disease who underwent 99mTc-MDP bone scintigraphy. The scans were performed by administering 99mTc-MDP (Methylene diphosphonate) to the patients proceeded by a whole body bone scintigraphy. The scans were evaluated for characteristic findings, including areas of increased uptake and involvement of skeletal regions. Clinical data and treatment regimens were also reviewed to assess the impact of bone scintigraphy.

Results: Observations: Of the 20 patients analysed with increased levels of alkaline phosphate, 90% exhibited significant areas of increased radiotracer uptake, primarily in the pelvis, skull, and long bones, also revealing asymptomatic involvement in 35% of cases. The study found that 99mTc-MDP bone scintigraphy were instrumental in confirming the diagnosis in 80% of cases, with abnormal radioactive tracer uptake proving to effectively delineated the extent of the disease. It’s high sensitivity and specificity makes it an essential modality in providing critical information for surgical planning in patients requiring orthopaedic interventions.

Conclusions and References: Thus 99mTc-MDP bone scintigraphy is a vital tool in the evaluation and management of Paget’s disease, offering valuable insights into disease extent and treatment response. This sensitive imaging modality is used for it’s ability to non-invasively visualize bone activity, enhances patient care and outcomes in this chronic condition.

Abstract ID: 68: Transfer learning in bone scintigraphy: Superior to early-career readers and comparable to experts in classifying skeletal metastasis

Aman Tilak, Bangkim Chandra Khangembam, Vikrant Kumar Goenka, Asem Rangita Chanu, Aman Tilak, Chetan Patel, Rakesh Kumar

Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Introduction: This study aimed to evaluate the role of transfer learning, a machine learning (ML) technique, in classifying skeletal metastases in bone scintigraphy images. The primary objective was to assess the efficacy of transfer learning in detecting osteoblastic skeletal metastases, and the secondary objective was to compare its performance with human readers.

Materials and Methods: A total of 2,510 patients with known malignancies who underwent bone scintigraphy were enrolled, including 2,368 retrospectively recruited (January 2017 to August 2022) and 142 prospectively enrolled (September 2022 to September 2023). Bone scintigraphy images were categorized as “normal,” “benign-degenerative,” or “metastasis,” based on clinical consensus, follow-up, or SPECT/CT findings. Thirteen supervised ML algorithms were tested, using Google’s InceptionV3 pre-trained model for transfer learning to extract image feature vectors (image embedding). Patients who underwent bone scintigraphy between January 2017 and August 2022 were randomly divided into training and validation sets using an 80:20 split ratio (1,895 patients for training, 473 for validation). The 142 prospectively enrolled patients formed the testing set. Models were evaluated using metrics such as Area Under the Curve (AUC), classification accuracy (CA), precision, recall, F1 score, and Log Loss. A random classifier served as a baseline reference for Log Loss to identify the most reliable and stable ML models. The Stuart-Maxwell test was used to compare the performance of ML models with human readers.

Results: Eight of the 13 ML algorithms demonstrated optimal performance, with Log Loss values lower than the random classifier and AUC > 0.900 during training and validation. These models were tested for generalizability on unseen data, where all but the Support Vector Machine (AUC < 0.800) achieved AUCs > 0.900. Logistic Regression was the best performer, with an AUC of 0.999, classification accuracy, precision, recall, F1 score of 0.993, and specificity of 0.998. Other top models included Neural Networks, Gradient Boosting, and Random Forest, all with AUCs > 0.900. The ML models processed images much faster than human readers, completing the interpretation of 142 images in 0.027 to 1.77 seconds, compared to 10 to 18 minutes for humans. Performance among human readers varied by experience, with less experienced readers (accuracy 43.7% to 54.2%) being outperformed by the models (P ≤ 0.002), while the most experienced reader (80.3%) performed comparably to the top-performing models (P ≥ 0.280).

Conclusions and References: Transfer learning demonstrates commendable diagnostic accuracy in classifying skeletal metastases, outperforming less experienced human readers while matching expert performance, and significantly improving diagnostic speed.

Abstract ID: 176: Unmasking the truth – Spotting and solving artifacts in bone scintigraphy

DivyaVelusamy, Julie Hephzibah, Saumya Sunny, Prabhu Titus Devakumar, N. T. Bivinjith

Department of Nuclear Medicine, Christian Medical College, Vellore, Tamil Nadu, India

Introduction: The aim of this study is to explain the various artifacts encountered in bone scintigraphy, their underlying causes, impacts on diagnostic accuracy, and effective strategies for their reduction.

Materials and Methods: This theoretical exploration is based on a comprehensive review of existing literature and clinical guidelines pertaining to bone scintigraphy artifacts. The exploration of artifacts can be categorized into several distinct types, detailing their causes and impacts on imaging results. Practical recommendations for minimizing these artifacts will include best practices in patient preparation, injection techniques, and equipment maintenance. The insights provided will be informed by experiences and observations from past cases, offering a framework for better artifact management in clinical settings.

Results: The significant artifacts affecting bone scintigraphy includes:

• ● Patient-Related Artifacts - (Contamination, Motion, Metallic Prosthesis,)

• ● Instrument Related Artifacts - (Equipment malfunctions, Uniformity (Ghosting effect), Edge packing artifacts, Image Contrast)

• ● Radiopharmaceutical-Related Artifacts – Free Pertechnetate (air in the vial, Excess alumina, RP breakdown, Insufficient Stannous ion)

• ● Technical Related Artifacts (Extravasations, Injection Site, Arterial & Central venous catheter injections).

These artifacts not only degrade image quality but can also lead to false positive scan results. Most of these artifacts can be routinely corrected after proper identification.

Conclusions and References: Bone scintigraphy is important for diagnosing bone metastases and musculoskeletal conditions, but artifacts can affect image quality and accuracy. To minimize these, it is essential to implement quality control measures for equipment, ensure proper labeling of Technetium-99m Methylene Diphosphonate (MDP), and address any labeling failures. By focusing on these steps, practitioners can reduce the need for repeat scans and unnecessary exposure, leading to better diagnostic accuracy and improved clinical management.

Abstract ID: 177: Uptake index on 99m TC-MDP Bone scintigraphy

R. Suganya, Julie Hephzibah, Prabu Titus, Saumya Sara Sunny

Department of Nuclear Medicine, Christian Medical College and Hospital, Vellore, Tamil Nadu, India

Introduction: Technetium-99m Methylene Diphosphonate (99m Tc-MDP) bone scintigraphy is a widely utilized non-invasive imaging modality recognized for its high sensitivity in identifying bone tumours, infections, and trauma. Despite its effectiveness, there is a scarcity of quantitative indices to differentiate various bone pathologies.

Aim: This study aims to establish a quantitative Bone Uptake Index (BUI) for identifying hot lesions in patients undergoing bone scintigraphy.

Materials and Methods: From March to August 2022, patients who underwent Tc99m-MDP scans were analysed. Each patient received an intravenous injection of 10-20 mCi of 99m Tc-MDP, followed by bone scans 2-3 hours post-injection using the OPTIMA NMCT 640 gamma camera. Image processing was conducted on the Xeleris workstation 3.0. Patients were categorized into three groups: (1) Normal bone study (done for non-oncological indications), (2) Metastatic disease from breast carcinoma, and (3) Metastatic disease from prostate carcinoma. The BUI was calculated using the formula: BUI = Hotspot ROI counts / Normal long bone (humerus) ROI counts. The shoulder joint was considered the Hotspot in the normal bone study. Those with metastasis to the humeri were excluded.

Results: A total of 56 patients were analysed, with the following distributions: Normal study: n=16 patients (age group 22 to 72) (Min: 2.2, Max: 4, Avg: 3, SD: 0.5), Metastatic Breast Carcinoma: n=20 (age group 22 to 71) (Min: 5.6, Max: 9, Avg: 7.3, SD: 1.1), and Metastatic Prostate Carcinoma: n=20 (age group 45 to 82) (Min: 5.9, Max: 25, Avg: 10.8, SD: 5.3).

Conclusions and References: This study successfully quantifies bone uptake to classify metastatic disease. The established normal BUI is approximately 3, with values exceeding 6 for breast carcinoma metastasis and 5.5 for prostate carcinoma metastasis. This quantitative approach enhances diagnostic accuracy and may assist in clinical decision-making.

Abstract ID: 214: Optimization of SPECT-CT parameters in Tc-99m bone scan

V. Gopika

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: SPECT -CT is a type of nuclear imaging test, which utilizes radioactive substance and a special camera to acquire 3-D images. Areas of bone healing or cancer progression are detected on SPECT scans, so this type of test is being used more frequently to help diagnose hidden bone fractures. SPECT-CT imaging can be processed with various parameters, reconstructions and filters.

Aim: To find the best combination of image reconstruction parameters in SPECT-CT imaging to derive the best image quality in Tc99m MDP (Methylene Diphosphonate) Bone scan.

Materials and Methods: Retrospective analysis of patients’ data who had undergone Tc99m MDP scan was done. The Planar bone scintigraphy and SPECT-CT images were acquired 3 hours post intravenous administration of Tc99m MDP. SPECT-CT images were reconstructed using various combinations of parameters like iterations, subsets and filters. OSEM (Ordered Subset Expectation Maximum) and FBP (Filter Back Projection) reconstructions were compared in Butterworth and Hann filter. Images of 10 patients with clinical indications such as Carcinoma Prostate, Carcinoma Breast and Femoral condylar AVN were reconstructed using various combinations of parameters.

Results: Images of 10 patients were reconstructed using various combinations of parameters.

• ● Best image quality was found when the critical frequency was in the range of 0.5-0.9 and power was in the range of 4-6 with 3 iteration and 8 subsets in Butterworth filter of OSEM reconstruction.

• ● Best image quality was achieved when power was in the range of 1.0-1.2 in Hann filter of OSEM reconstruction.

Conclusions and References: The combination of filters, subsets and other reconstruction parameters along with uptake duration and scanning time per projection contributes to optimal image quality and enhances diagnostic accuracy in SPECT-CT in bone imaging.

Abstract ID: 59: Diagnosis of hyperparathyroidism using 99m TC-sestamibi

S. Akash, E. Venkatachalapathy, Palani, Sibu, Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Hyperparathyroidism is a condition characterized by excessive secretion of parathyroid hormone (PTH), which leads to elevated calcium levels in the blood. Accurate localization of hyperactive parathyroid glands is crucial for appropriate diagnosis. The use of imaging techniques such as technetium 99m sesta Methoxy Iso Butyl Isonitrile (99mtc-sestamibi) has been increasingly recognised for its efficacy in diagnosing and localizing abnormal parathyroid glands, particularly in cases of hyperparathyroidism.

Aim: The aim of the study to evaluate the diagnostic accuracy of 99mtc-sestamibi scintigraphy in detecting hyperactive parathyroid glands.

Materials and Methods: Sample size: 25. Patients with increased PTH levels with a suspect of hyperparathyroidism underwent 99mtc-sestamibi scintigraphy. The imaging protocol involves a dual phase imaging:

• ● Early phase (15 minutes post injection)

• ● Delayed phase (2 hours post injection)

The study examines the efficacy of 99mtc-sestamibi in detecting abnormal parathyroid glands from surrounding tissues. The study was compared with ultrasound to evaluate the diagnostic accuracy.

Results: 99mtc-sestamibi scintigraphy has shown high sensitivity and specificity in identifying hyper functioning parathyroid tissue. The early phase often reveals increased uptake, but it is the delayed phase that provides clearer differentiation with abnormal parathyroid tissue. 99mtc- sestamibi provides detailed functional Information whereas ultra sound Are inconclusive.99mtc-sestamibi scintigraphy is a highly effective tool for the diagnosis and localization of hyperactive parathyroid glands in patients with hyperparathyroidism. It’s ability to provide both anatomical and functional insights enhances pre-operative planning. When combined with other imaging modalities like ultrasound, 99mtc-sestamibi improves diagnostic precision, making it a essential tool in the management of hyperparathyroidism.

Conclusions and References: 99mtc-sestamibi scintigraphy is a highly effective tool for the diagnosis and localization of hyperactive parathyroid glands in patients with hyperparathyroidism. It’s ability to provide both anatomical and functional insights enhances pre-operative planning When combined with other imaging modalities like ultrasound, 99mtc-sestamibi improves diagnostic precision, making it a essential tool in the management of hyperparathyroidism.

Abstract ID: 162: Accuracy of SPECT-CT fusion imaging in the diagnosis of hyperparathyroidism over planar imaging

B. Kavish Darshan, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: In this study, we aimed to analyze the diagnostic accuracy of planar imaging and fused single photon emission computed tomography/ computed tomography (SPECT-CT) images in localization of parathyroid adenoma.

Materials and Methods: 20 patients with primary hyperparathyroidism (PHPT) were imaged with planar image at 15 and 60 minutes after the intravenous injection of technetium99m-methoxyisobutylisonitrile (99mTc-MIBI). All patients underwent SPECT-CT of neck and chest.

Results: Among 20 Patients Planar Image Showed Focal Uptake In 15 Patients. SPECT-CT Fusion Images Were Able to Detect parathyroid in all 20 patients. Parathyroid Adenomas even with the size of 6 mm is detected in SPECT/CT. Average Size>8 mm Is Seen In Planar Imaging And average size <8 mm Is Seen In SPECT CT.SPECT/CT helped in exact localization and helped surgeon to remove the correct lesion.

Conclusions and References: SPECT-CT fusion imaging is a more useful tool for localization of small parathyroid adenoma in comparison with planar imaging.

Abstract ID: 24: Role of 18fluorine-fluoro-deoxy- glucose PET/CT in predicting egfr mutation and positive alk expression in patients with advanced nonsmall cell lung cancer – A prospective study

Mandakinee Phukan, Neelakshi Mahanta, Hitesh Deka, Barasha Sarma Bharadwaj, Bhaskar Das

State Cancer Institute, Gauhati Medical College Affiliated with Srimanta Sankaradeva University of Health Sciences, Guwahati, Assam, India

Introduction: Mutation in epidermal growth factor receptor (EGFR) and rearrangement of echinoderm microtubule associated protein-like 4 (EML4) –anaplastic lymphoma kinase (ALK) occurs in advanced non-small cell lung cancer (NSCLC) which can be successfully treated with tyrosine- kinase inhibitors. In some patients, biopsy is not feasible. We aimed to evaluate whether maximal standardized uptake value (SUVmax) of the primary tumor (pSUVmax), nodal metastasis (nSUVmax) and distant metastasis (mSUVmax) obtained from 18Fluorine-Fluorodeoxyglucose (18F-FDG) PET/CT scan helps to non-invasively determine EGFR mutation and ALK rearrangement in NSCLC.

Materials and Methods: 65 patients with histopathologically confirmed NSCLC visiting our hospital from January 2021 to January 2023 underwent 18F-FDG PET/CT scan prior to treatment. Their relevant clinicopathological data were obtained. pSUVmax, nSUVmax and mSUVmax were calculated and multivariate regression analysis has been applied to identify predictors of EGFR mutation and ALK rearrangement.

Results: EGFR mutation and ALK rearrangement found in 29 (45%) and 15 (23%) patients respectively. Multivariate analysis revealed that low pSUVmax with cut-off of 8.65, high mSUVmax with cut-off of 9.2 along with female sex, adenocarcinoma and stage IV disease are better predictors of EGFR mutation (p value 0.01, Positive predictive value: 65.94%, Negative predictive value: 75.45%). Similarly, high nSUVmax (cut off >4.4) along with male sex, non-smokers, adenocarcinoma and stage IV disease had higher association with ALK rearrangement (p value 0.001, Positive predictive value: 57.04%, Negative predictive value: 93.21%).

Conclusions and References: Our study concluded that low pSUVmax and high mSUVmax obtained from 18F-FDG PET/CT scan when combined with relevant clinicopathological factors is a valuable tool for non-invasively predicting EGFR mutation. Similarly high nSUVmax obtained from 18F-FDG PET/CT scan along with other relevant clinicopathological factors helps in predicting ALK rearrangement in patients whom biopsy cannot be obtained.

Abstract ID: 36: Identifying the significance of high tonsillar metabolic uptake in cases of lymphoproliferative disorders to rule out neoplastic etiology

M. Vigneshwaran, D. K. Gupta, Sanjeeva Bharadwaja, A. G. Pandit

INHS Asvini, Mumbai, Maharashtra, India

Introduction: Biopsy for tissue confirmation in follow-up lymphoma cases exhibiting FDG avid uptake on PET-CT in the head-neck region is a standard practice; however, literature lacks consensus on the necessity of such procedures post-chemotherapy. This study aims to evaluate the significance of PET-CT findings (SUVmax ≥ 5.0) in assessing remission or pathological status in these patients.

Materials and Methods: A retrospective cohort analysis was performed, encompassing 40 follow-up lymphoma cases (Group A) with SUVmax ≥ 5.0 on PET-CT, and 40 non-lymphoma cases (Group B) with comparable PET-CT findings. All patients in Group A underwent tonsillectomy, with histopathological results correlated with PET-CT outcomes. Group B cases received comprehensive clinical evaluations relative to their PET-CT findings. A Receiver Operating Characteristic (ROC) curve was plotted to analyze the data statistically.

Results: Analysis of the ROC curve for SUVmax indicated a sensitivity of 90% while yielding a specificity of only 10% and an insignificant P-value of 0.733, suggesting limited diagnostic utility of SUVmax alone in this context.

Conclusions and References: Our findings indicate that unnecessary biopsies in cases exhibiting FDG avid uptake should be discouraged unless supported by a comprehensive clinical picture showing asymmetry, significant lymph node involvement, and corresponding CT findings. Relying solely on PET-CT may introduce unnecessary risks and elevate treatment costs.

Abstract ID: 48: Case report: A rare case of primary DLBCL of the bone

Rohit Bulchandani, Saloni Gadikar, H. V. Sunil, Bushra Sadeed

Narayana Hrudayalaya, Bengaluru, Karnataka, India

Introduction: Primary lymphoma of the bone (PLB) is a rare lymphoproliferative disorder that comprises 5-7% of extranodal lymphomas. PLB more frequently affects the axial skeleton than the appendicular skeleton and is more commonly seen in men than in women.

Materials and Methods: Case report: A 73 Y/M male presented with back pain since 9 months with partial relief with NSAIDs. The patient also had associated complains of tingling paresthesias in bilateral lower limb. The patient had a history of pulmonary Koch’s diagnosed 15 months ago; the patient was treated with ATT for 6 months. On examination it was noticed that the patient tends to walk slightly wide based. Generalized spine tenderness and bilateral hip tenderness were elicited. On further evaluation, the LDH was normal. An MRI of the thoracic and lumbar spine with cervical spine screening showed heterogeneous involvement of T7-T9 vertebrae with soft tissue component and extension into epidural and neural foramina causing cord compression with oedema, these were suggestive of neoplastic versus infective aetiology. An 18F-FDG-PET/CT was done for further evaluation which showed : Hypermetabolic lytic-sclerotic lesion with bone destruction involving T7, T8 and T9 vertebrae and head of the right 8th rib and adjacent Hypermetabolic pre and paravertebral soft tissue components, which were suggestive of: 1. Koch’s aetiology, 2. Multiple myeloma. However, The Protein electrophoresis showed No evidence of monoclonal gammopathy.

Results: PET-directed-CT-guided biopsy was taken from the T8 vertebra. The histopathology features were suspicious for haemato-lymphoid malignancy. IHC markers showing atypical cells expressing CD20, BCL6 and MUM1 were suggestive of a high grade B-cell lymphoma favoring DLBCL (non-GCB). Thus this patient was started on the R-CEOP regimen. An interim 18F-FDG-PET/CT was done for after 3 cycles, which showed partial response. After 6 cycles of R-CEOP regimen, the patient underwent another 18F-FDG-PET/CT and the scan showed Interval resolution of FDG uptake in sclerotic changes involving T7, T8 and T9 vertebrae and in the lesion in head of the right 8th rib. These were suggestive of complete response to therapy.

Conclusions and References: Hypermetabolic lytic lesions with a soft tissue component largely point towards multiple myeloma. The presence of a recent history of Pulmonary Koch’s also increased the differentials. However, this case is a rare example of a Primary bone marrow lymphoma, which is a very rare entity in which clinicobiological significance is not well defined, but perceived to represent a particularly poor-risk subclass.

Abstract ID: 49: Kidney to liver SUV ratio as a novel biomarker for multiple myeloma: Insights from a retrospective PET/CT study

Malay Mishra, Deepanksha Datta, Sameer Taywade, Rajesh Kumar

Department of Nuclear Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Multiple myeloma is a hematologic malignancy characterised by clonal plasma cell proliferation. Until recently, the role of 18F-FDG PET/CT was limited to baseline evaluation of osteolytic lesions and response monitoring, for which it has been included in IMWG 2019 recommendations. Recently, new areas in the myeloma spectrum have been investigated using PET/CT, including dual time point imaging, and AI, among others. We propose a novel Kidney to Liver SUV ratio that may enhance diagnostic accuracy, serving as a potential biomarker to differentiate myeloma from non-myeloma cases.

Materials and Methods: This is a retrospective study of 51 myeloma and non-myeloma patients who underwent 18F-FDG PET/CT between January 2021 and July 2024. A database search used the keywords “myeloma” and “NCCT”. Patients were then classified into 26 multiple myeloma and 25 non-myeloma patients, and their demographic data was extracted (age, sex). Renal cortical ROIs were drawn manually at the level of the interpolar plane, excluding the pelvicalyceal uptake for both kidneys. Hepatic ROI was drawn manually over the caudate lobe. SUV average of both kidneys, SUV liver and SUV ratios of the kidney (average) to the liver were noted. Statistical analysis used descriptive statistics, hypothesis testing using Mann Whitney U test and ROC analysis.

Results: Mean SUV ratios were significantly higher in myeloma (2.02+/-0.56) than in non-myeloma patients (1.01+/-0.21). Mann Whitney U test performed suggested a statistically significant difference in the SUV ratios between myeloma and non-myeloma patients (p-value <0.001). ROC analysis revealed the AUC to be 0.998, indicating high diagnostic accuracy in differentiating the two groups. The results demonstrate that the kidney-to-liver SUV ratio is significantly higher in myeloma patients compared to non-myeloma patients, suggesting it could be used as a non-invasive biomarker to complement other diagnostic criteria in myeloma patients.

Conclusions and References: Statistical analysis suggests that the kidney-to-liver SUV ratio could serve as a valuable tool in diagnosis, disease monitoring and quantitative evaluation of renal involvement in myeloma patients.

Abstract ID: 57: 18FDG PET/CT in adenocarcinoma and squamous cell carcinoma of lung

Mehul Dulet, Deepanksha Datta, Sameer Taywade, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Adenocarcinoma and Squamous Cell Carcinoma are the predominant histological subtypes in Non-Small Cell Lung Carcinoma. It is necessary to differentiate between the two because genetic alterations that can be targeted by drugs are mainly seen in Adenocarcinoma, and so unnecessary drugs can be avoided in cases of Squamous Cell Carcinoma. Also, the metastatic potential of Adenocarcinoma is high and is associated with a poorer Disease-Free Survival. In approximately 62% cases the TNM staging is modified after an 18FDG PET-CT scan, thus also preventing patients from undergoing unnecessary further investigations.

Aim: To study the association of 18FDG PET-CT metabolic parameter - SUVmax (Standard Uptake Value) with Adenocarcinoma and Squamous Cell Carcinoma of lung.

Materials and Methods: It is a cross-sectional study in diagnosed cases of Squamous Cell Carcinoma and Adenocarcinoma of lung which were referred to the Department of Nuclear Medicine, AIIMS Jodhpur for 18FDG PET-CT for staging. Patients of either sex, age group more than or equal to 18 years, who have been diagnosed with Squamous Cell Carcinoma or Adenocarcinoma of lung were approached for participating in this study. Patients were informed about the study procedure, the possible benefits, and any adverse outcomes and a patient information sheet was provided. They were enrolled after an informed written consent. 18FDG was administered intravenously in doses of 0.1-0.2 mCi/kg. Whole Body images were acquired after 45-60 minutes post injection. Images were reconstructed using iterative reconstruction. Reconstructed images were used to calculate the quantitative parameter of SUVmax: SUV = Radioactivity Concentration (kBq/mL) / [Injected Dose (kBq) / Weight (g)]. The mean value of SUVmax in the two groups was expressed as mean±SD with 95% CI. The quantitative variables in two groups were compared by using the Mann-Whitney U test (non-parametric test). ‘p’ value of less than 0.05 was considered as statistically significant.

Results: Ten cases, each of Adenocarcinoma and Squamous Cell Carcinoma were recruited. The mean age at presentation was 60 years. Smoking was identified as the risk factor among 19 cases. An upper lobe primary lesion was observed in 12 cases. The mean±SD for Squamous Cell Carcinoma was 22.1±9.67 and for Adenocarcinoma was 13.9±4.14. A ‘p’ value of 0.045 was obtained.

Conclusions and References: A higher value of SUVmax was observed in cases of Squamous Cell Carcinoma as compared to Adenocarcinoma of lung on 18FDG PET-CT.

Abstract ID: 58: Advantages of MR fusion with PET/CT in cases of rectal carcinoma

S. Akash, E. Venkatachalapathy, Palani, Sibu, Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Rectal carcinoma remains a significant challenge in oncology requiring a precise diagnostic and therapeutic strategies. Magnetic Resonance Imaging (MRI) AND Positron Emission Tomography/Computed Tomography (PET/CT) are powerful tools for cancer diagnostics. In rectal carcinoma (ca rectum) the integration of MR fusion with PET/CT offers an enhanced visualization of tumor anatomy and metabolism. This study aims to explore the clinical advantages of MR fusion with PET/CT in detecting, staging, and monitoring rectal carcinoma.

Materials and Methods: A Retrospective analysis was conducted on 20 patients with carcinoma of Rectum. Sample size (N) = 20. This evaluate the advantages of MR fusion with PET/CT imaging in the management of rectal carcinoma cases. The image findings with PET/CT were analyzed in terms of focusing on tumor localization, lymph node involvement and response to therapy.

Results: MR fusion with PET/CT provided superior anatomical detail and metabolic activity mapping, leading to improved tumor delineation and staging accuracy. There were notable advantages of:

• ● Tumour localization,

• ● Involvement of surrounding structures,

• ● Response to treatment,

• ● Differentiating between scar tissue and residual tumor,

• ● Detecting metastatic lesions,

• ● Improving the accuracy of diagnosing rectal cancer especially for t3 tumors and loco regional extensions.

Integration of MR fusion with PET/CT showed higher sensitivity and specificity compared to individual imaging techniques.

Conclusions and References: MR fusion with PET/CT offers significant advantages in the management of carcinoma of Rectum by providing more accurate staging assessment and better treatment planning. This hybrid imaging modality could potentially serve as a new standard in rectal cancer for enhancing therapeutic outcomes and minimizing treatment related complications in rectal carcinoma patients.

Abstract ID: 60: Metabolic intralesional heterogeneity: A valuable and straight forward metabolic parameter in carcinoma breast

Y. T. Yogananda, Deepanksha Dutta, Sameer Taywade, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Intralesional heterogeneity in breast cancer refers to the differences in tumor cell characteristics found within a single tumor mass. This heterogeneity plays several critical roles, including influencing tumor evolution, contributing to treatment resistance, impacting prognostic assessments, aiding in biomarker discovery, affecting imaging techniques, and shaping interactions within the tumor microenvironment, which in turn informs therapeutic strategies. Breast carcinoma is classified into molecular types based on receptor expression, including Luminal A, Luminal B, HER2-enriched, and triple-negative breast cancer (TNBC). Notably, TNBC exhibits significant heterogeneity, with variations in cellular composition, immune cell infiltration, and genetic mutations (such as BRCA1 mutations), leading to diverse responses to chemotherapy and the development of resistance mechanisms. Therefore, this study aims to assess intralesional metabolic heterogeneity across different molecular types of breast cancer, which is essential for enhancing treatment outcomes and advancing personalized medicine strategies.

Aim: To evaluate the significance of metabolic intralesional heterogenicity in various molecular subtypes of breast cancer.

Materials and Methods: This is a retrospective study conducted in patients of histopathologically proven breast carcinoma who underwent staging by 18F-FDG PET/CT. The Intralesional metabolic heterogeneity index (SUV max – SUV mean) of the primary tumor was calculated for the patients and subgroup analysis was done by comparing this metabolic index between various molecular subtypes of the breast carcinoma using Mann-Whitney U test (non-parametric test). ‘P’ value of less than 0.05 was considered as statistically significant.

Results: A significant difference was observed in the Intralesional metabolic heterogeneity index between the Triple receptor positive and triple receptor negative groups (p value = 0.033), with a higher value of this index noted in the triple receptor negative group. However, no statistically significant difference in the metabolic index was noted in the other receptors groups as well as the molecular subtypes.

Conclusions and References: A higher Intralesional metabolic heterogenicity index on FDG PET/CT is observed in triple receptor negative breast cancer. This index can serve as a prognostic tool aiding further patient management.

Abstract ID: 76: Utility of dual point 18F FDG PET/CT in management of locally advanced carcinoma cervix

Tekchand Kalawat, S. Muneendra Kumar, M. Ranadheer Gupta, A. Y. Lakshmi, T. Kannan, H. Narendra, H. Rukmangadha, Pranababdhu Das

Department of Nuclear Medicine, Srivenkateswara Insitute of Medical Sciences, Tirupati, Andhra Pradesh, India

Introduction: Carcinoma cervix is the fourth common cancer diagnosed in female population and is the fourth most common cause of cancer related mortality worldwide. Management of carcinoma cervix is stage based, so an accurate staging of the disease is essential. In this study we evaluated the utility of dual point in management of locally advanced carcinoma cervix.

Aim: To study the utility of dual point 18F FDG PET/CT in staging of locally advanced carcinoma cervix.

Materials and Methods: We prospectively evaluated 45 patients, histopathologically proved treatment naive locally advanced squamous cell carcinoma cervix with 18F FDG PET/CT. Initial imaging was done 60 minutes post 18F FDG injection and delayed imaging was done after 180 minutes post 18F FDG injection. 18F FDG PET/CT findings were compared with conventional imaging findings.

Results: Total of n=45 patients were included in the study. Based on the findings of 18F FDG PET/CT, 60% of the cases were upstaged. In 8.8% of the cases additional image findings were observed in delayed imaging. In 26.6 % of the patients 18F FDG PET/CT localized distant metastases and management plan was changed from curative to palliative intent.

Conclusions and References: 18F FDG PET/CT is highly useful in staging of locally advanced carcinoma cervix and changed the management plan in 60% of the patients. Delayed diuretic phase imaging improved the image quality and interpretation; however no significant information was added to the initial image findings to change the management.

Abstract ID: 81: Exploring the 18F FDG-PET/CT signature of mycosis fungoides: A case series

Prateek Singh Bisht, Deepanksha Datta, Sameer Taywade, K. M. Althaf, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Mycosis Fungoides (MF) is a rare cutaneous T-cell lymphoma characterized by skin lesions and potential systemic involvement. The etiology remains unclear, but factors such as genetic predisposition and environmental triggers plays a role. The prognosis of MF depends on various factors, stage of disease being a crucial one, for which Whole Body 18 FDG-PET/CT Scan can be used for in baseline evaluation and response assessment.

Aim: This study evaluates the 18F FDG-PET/CT imaging features of MF, focusing on metabolic activity of lesions and extracutaneous involvement in staging.

Materials and Methods: We retrospectively reviewed (by experienced Nuclear medicine Physicians) the PET/CT scans (NAC and AC images) of three cases of biopsy-proven MF, aged 31-44 years, presenting with varied cutaneous manifestations. 18F FDG-PET/CT imaging was utilized to assess the metabolic activity of skin lesions and lymph nodes, quantified by SUVmax (standardized uptake value). Additionally, the thickness of the skin lesions and lymph node dimensions were measured.

Results: Patient 1 (Male, 44 years) presented with nodular lesions in the groin and iliac regions. Metabolically active thickening of skin lesions was observed in the scalp, axillae, and lower extremities, with the right gluteal lesion showing an SUVmax of 7.4. Several lymph nodes, including right femoral (SUVmax 3.8) and right axillary level I (SUVmax 3.2), showed heterogeneous FDG uptake, suggesting disease involvement. Patient 2 (Female, 31 years) had multiple erythematous scaly lesions. FDG avidity was noted in cutaneous lesions along the trunk and extremities, with a maximum SUVmax of 4.5. Lymph node involvement was less prominent, with indeterminate axillary and inguinal nodes showing minimal FDG uptake (SUVmax 1.5). Patient 3 (Female, 41 years) presented with painful ulcerative skin lesions. Extensive metabolically active cutaneous and subcutaneous lesions were observed, particularly in the bilateral limbs and perineal region (SUVmax 18.6). Significant lymph node involvement was noted, particularly in the right cervical and perihumeral regions (SUVmax 3.5 and 8.0, respectively). Histopathology from perihumeral lymph node was positive for MF.

Conclusions and References: FDG-PET/CT provides valuable insight into the metabolic activity of MF lesions and helps identify systemic involvement through lymph node assessment. The study highlights the heterogeneity in FDG avidity, with SUVmax values correlating with disease burden and lymphatic spread.

Abstract ID: 88: Unveiling diagnostic potential: FDG PET/CT in mucosal melanoma – An institutional perspect

Madan Gopal Vishnoi, Archna Yadav, A. V. S. Anil Kumar, Anurag Jain, Vaibhav Jain, Vempa Satish

Army Hospital R and R, Delhi, India

Introduction: Mucosal malignant melanoma (MMM) is a rare but aggressive form of melanoma that arises from mucosal surfaces, such as the oral cavity, anorectum and other regions. 18F-FDG PET/CT provide a whole-body view allows for the detection of distant metastatic disease, which is often missed by conventional imaging techniques like CT or MRI. We present the study evaluating the role of ¹⁸F-FDG PET/CT in the staging and management of mucosal melanoma, based on data from 10 patients collected over three years. The study demonstrates the value of FDG PET/CT in improving diagnostic accuracy and therapeutic decisions in mucosal melanoma.

Materials and Methods: In this prospective study, data were collected over a three-year period from 10 patients diagnosed with mucosal melanoma at a single institution. The cohort included one patient with mucosal malignant melanoma of the gingiva, two patients with melanoma of the hard palate, one with anal canal involvement, and four with nasal sinus melanoma. Each patient underwent ¹⁸F-FDG PET/CT scanning for staging or restaging purposes. Conventional imaging findings were compared with those of PET/CT, and any changes in staging based on PET/CT results were documented.

Results: We performed the study with prospective collection of data of diagnosed cases of mucosal malignant melanoma sent to Department of nuclear medicine for staging purpose. All patients were confirmed to have malignant melanoma through histopathological examination (HPE). We have 10 patient with 06 male and o4 female patients with age ranging from 30 to 70 years. Most patient presented with pigmented painless lesion of long duration. Duration was ranging from 05 months to 15 year. Lymph node involvement was present in most of the patients. Cervical lymph nodes were commonly affected in patients with head and neck mucosal melanomas. One patient with anal canal melanoma had pelvic and abdominal metastases. PET/CT scans upstaged the disease in 4 out of 10 patients (40%), revealing additional metastases not detected by conventional imaging methods. This upstaging played a critical role in altering the treatment approach for these patients.

Conclusions and References: ¹⁸F-FDG PET/CT plays a crucial role in the accurate staging and management of mucosal melanoma, as it was instrumental in detecting occult metastases and upstaging disease in a significant proportion of patients. These findings highlight the importance of FDG PET/CT in improving the diagnostic and therapeutic approach for patients with mucosal melanoma.

Abstract ID: 91: Brown fat FDG uptake – A common finding in FDG PET CT scan and the relation to demographic, environmental, and clinical factors

Anurag Jain, M. G. Vishnoi, Abhishek Mahato, Vikrant Balan

Command Hospital, Lucknow, Uttar Pradesh, India

Introduction: Brown adipose tissue (BAT) is crucial for thermogenesis and energy expenditure. This study examines the demographic, environmental, and clinical factors influencing brown fat FDG uptake, particularly in relation to its anatomical distribution, body mass index (BMI), gender, and temperature.

Materials and Methods: Data from 139 participants were analyzed, documenting demographics, BMI, weight, and environmental temperatures. FDG uptake by BAT at various anatomical sites was assessed using PET/CT scans. Statistical analyses, including chi-square tests, Fisher’s exact tests, and Mann-Whitney U tests, were conducted to explore the associations between BAT uptake and the variables of interest.

Results: Participants had a mean age of 37.87 ± 15.67 years, with 41.73% males and a mean BMI of 19.59 ± 4.52 kg/m². The most common BAT uptake sites were between the anterior neck muscles and the supraclavicular fossa (99.28%), under the clavicles (66.19%), and in the axilla (44.60%). No significant association was found between BMI and BAT uptake at most sites, except around solid organs (p = 0.03). Females showed higher BAT uptake under the clavicles (p = 0.02). Higher ambient room temperatures correlated with increased BAT uptake at perivascular, periviscus, and solid organ sites (p < 0.01). Conversely, lower external temperatures were linked to higher BAT uptake at similar sites.

Conclusions and References: Our findings highlight the significant influence of gender and environmental temperatures on BAT uptake. The thermogenic role of BAT in colder conditions underscores its metabolic significance. Further research is needed to explore the underlying mechanisms of these associations and their potential implications for metabolic health interventions.

Abstract ID: 96: Incremental value of 18 F FDG PET CT over CT in predicting response to immune checkpoint inhibitor therapy in solid tumours

Abhishek Uppal, Ishita B. Sen, Dharmender Malik, Parul Thakral, Mrinalini Koley, Darshan Thakrani, Jatin Gupta

Fortis Memorial Research Institute, Gurugram, Haryana, India

Introduction: Immunotherapeutic agents constitute an integral part of treatment regimens of multiple solid tumours. While evaluating response to immunotherapeutic drugs, it is essential to differentiate pseudo-progression from true progressive disease. FDG PET might predict changes in metabolism which tend to occur before the traditional morphological changes assessed by CT or MRI and might therefore pick up true progressive disease earlier. We compared PET CT based response evaluation (iPERCIST) with CT based response evaluation (iRECIST) to assess the incremental value, if any, of PET CT over CT alone in assessing response to immunotherapy drugs in solid tumours.

Materials and Methods: 40 patients on immune checkpoint inhibitor therapy were included. FDG PET CECT was done at baseline, after 4 cycles of immunotherapy and at the end of 7-8 cycles of immunotherapy. Patients were classified as having treatment response (complete or partial), progressive disease or stable disease, using both iRECIST and iPERCIST. Cohen’s kappa coefficients with quadratic weights were used to assess concordance between ratings obtained at baseline and follow up separately for iRECIST and iPERCIST. Z-test for the two independent kappa values were calculated to determine if statistically significant differences exist. All p-values reported are two-tailed and the and the < 0.05 was considered to be statistically significant.

Results: 30 out of 40 patients, had either response or stable disease on the first follow up by iRECIST and iPERCIST. With iPERCIST, 10 patients had immune unconfirmed metabolic progression, of these, 8 showed CPMD (Confirmed progressive metabolic disease), while only 2 had PMR (Partial metabolic response) on the follow up scan. In the iRECIST group however, only 7 patients had IUPD (Immune unconfirmed progressive disease), and of these, 1 developed PR (Partial response), 5 CPD (Confirmed progressive disease) and 1 SD (Stable disease). The remaining 3 had stable disease at first and second follow up scans. The quadratic weighed kappa at 1st follow up and at 2nd follow up for iPERCIST was 0.6925 (substantial correlation), and for iRECIST was 0.3137 (fair correlation). This difference was statistically significant (p=0.022) when tested using a two-tailed Z-test.

Conclusions and References: PET CT based iPERCIST criteria using metabolic data picked up true progressive disease earlier compared to CT based iRECIST criteria using morphologic data alone. PET CT might help in selecting patients with true progression earlier, thereby facilitating a change in treatment regimen and influencing patient outcomes.

Abstract ID: 113: Correlation of metabolic parameters of FDG PET/CT with tumor marker levels in cases of recurrent carcinoma ovary

Ritesh R. Suthar, Saloni Rajkotia, Abhishek Palsapure, Bijal Patel, Shashank Pandya

The Gujarat Cancer and Research Institute, Ahmedabad, Gujarat, India

Introduction: 1. Correlation of metabolic parameter of FDG PET/CT (MTV and TLG) with tumor marker levels in epithelial recurrent carcinoma ovary (CA 125 and HE4 levels). 2. Minimum cutoff of tumor marker level to get highest sensitivity and specificity of FDG PET/CT.

Materials and Methods: Retrospective Analysis All individuals aged >18 years with biopsy-proven epithelial carcinoma ovary who underwent FDG PET/CT to evaluate recurrent state of disease were included.

Results: Total 42 patients were included in study. Correlation between tumor marker level i.e. CA 125 and HE4 with FDG PET/CT metabolic parameter were examined using Karl Pearson’s correlation coefficient method.

Correlation between CA 125 with MTV and TLG:

CA 125 and MTV

Karl pearson Corr coffi(R) 0.761

Sig value 0.01

CA 125 and TLG

Karl Pearson Corr coffi 0.746

Sig value 0.01

Correlation between HE4 and MTV and TLG:

HE4 and MTV

Karl pearson Corr coffi(R) 0.752

Sig value 0.01

HE4 and TLG

Karl Pearson Corr coffi 0.745

Sig value 0.01

Cut-off Value of Positive Findings on FDG PET/CT with tumor marker level was calculated using ROC curve.

CA 125 ROC curve: By Minimum Specificity-sensitivity we get cut off value for CA125 value is 34.5

0 U/mL

HE4 ROC curve: By Minimum Specificity-sensitivity we get cut off value for HE4 value is 88.50 pmol/L

Conclusions and References: FDG PET/CT is sensitive modality to diagnose recurrence of carcinoma ovary and its metabolic parameter very well correlates with tumor marker level. However, we need large prospective study to establish these findings.

Abstract ID: 114: Utility of 18-FDG PET/CT in staging soft tissue sarcoma: A retrospective single centre experience

K. M. Althaf, Deepanksha Datta, Sameer Taywade, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Soft tissue sarcomas are rare, aggressive mesenchymal tumors with a high rate of metastasis in initial diagnosis. Surgery is the mainstay of treatment, and it may defer in case of disseminated disease. No optimum imaging approaches have yet been established to evaluate initial evaluation. This study attempts to identify the role of 18-FDG PET/CT for the staging soft tissue sarcoma.

Materials and Methods: We retrospectively included 12 consecutive biopsy-proven soft tissue sarcoma cases from February 2021 to February 2024. An experienced nuclear medicine physician evaluated the images as a single integrated imaging modality. Clinical follow-up (minimum six months), follow-up PET/CT, and histopathology were taken as the reference standard for final diagnosis.

Results: Out of 12 patients, 9 were females (75%), and their median age was 46.5 (IQR: 37.5- 55). The indication for referral was staging in 9 patients (75%) and restaging after surgery in 3 patients (25%). Documented histopathological diagnosis were synovial sarcoma (3), pleomorphic sarcoma (3), spindle cell sarcoma (4), and undifferentiated sarcoma (2). 18-FDG PET/CT showed lymph node metastasis in 7 patients (58%) and distant metastasis in 8 patients (66%). The diagnostic sensitivity, specificity, PPV, and NPV of 18-FDG PET/CT to detect lymph node metastasis were 100, 71.4, 71, and 100%, respectively. The diagnostic sensitivity, specificity, PPV, and NPV of 18-FDG PET/CT to detect distant metastasis were 100, 80, 87.5 and 100%, respectively.

Conclusions and References: 18F-FDG PET/CT, as a single integrated modality, is beneficial for staging/restaging purposes in soft tissue sarcoma patients and shows high sensitivity in detecting the lymph nodes and distant metastasis.

Abstract ID: 116: Effect of variation in standard uptake value max with varying regions of interest on solid tumors in F18 FDG PET CT

Darivemula Graham Stains, Julie Hephzibah, Saumya Sara Sunny, Prabu Titus Devakumar

Christian Medical College and Hospital, Vellore, Tamil Nadu, India

Introduction: To find an optimal size of the ROI to estimate the SUVMax for FDG positive unifocal lesions in patients undergoing F18 FDG PET CT and to study the effect of variation in SUVMax with varying ROIs.

Materials and Methods: Patients diagnosed with Lung Carcinoma with FDG positive unifocal lung tumours were included. The data sets of patients were analysed using PET workstation Syngovia (Siemens healthineers). A unifocal lesion with a diameter of more than 3 cm was selected for each patient. ROIs were drawn around a solid tumour in concentric circles of varying diameters in the order of 3 cm, 2.6 cm, 2 cm, 1.6 cm, 1 cm, 0.6 cm from periphery to centre. The SUVMax values obtained from each of the ROIs (SUVMax 0.6, SUVMax 1.0, SUVMax 1.6, SUVMax 2.0, SUVMax 2.6, SUVMax 3.0) were recorded. Value obtained with a larger ROI covering the whole lesion beyond the tumoral boundaries was also recorded (SUVMax whole). All the SUVMax values were recorded and compared.

Results: A total of 10 patients (5 M/ 5 F with age ranging from 31 years – 76 years) from Jun 2024 to Sept 2024 were included in the study. When ROIs ranging from 0.6 to 1.6 cm were used, the SUVMax results (SUVMax 0.6, SUVMax 1.0, SUVMax 1.6) were underestimated, possibly because it was too small to include the voxel of highest uptake in the lesion. However, while ROIs ranging from 2 cm – 3 cm were drawn, the SUVMax values (SUVMax 2.0, SUVMax 2.6, SUVMax 3.0) did not differ significantly from each other. This was also comparable to the SUVMax obtained from the ROI drawn around the whole lesion beyond the tumoral boundaries (SUVMax whole). It was also observed that in all the patients, the highest SUVMax obtained was the SUVMax whole. This could be attributed to the potential overestimation by including surrounding areas of physiological uptake.

Conclusions and References: The size of the ROI can create minor differences in SUVMax values of tumoral lesions. An ROI of minimum 2 cm is required to avoid erroneous under-estimation. Care should be taken not to draw large ROIs beyond the tumoural boundaries to avoid over-estimation due to inclusion of areas with physiological uptake. Implementing this optimal size of ROI (range of 2-3 cm) can refine the clinical practice of SUVMax estimation and decrease inter-observer variability.

Abstract ID: 125: Unusual presentation of a common malignancy

P. Sathya Narayanan, Satywati Deswal

Dr. Ram Manohar Lohia Instituen of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Lymphomas encompass a diverse array of lymphoid malignancies, characterized by varied clinical behaviors and therapeutic responses. Prognosis is influenced by histological type, clinical variables, and increasingly, molecular characteristics.

Materials and Methods: We report a 69-year-old male with no significant comorbidities who presented with a six-month history of episodic diplopia that improved with steroids. Neuroimaging, including NCCT and CEMRI, revealed no significant abnormalities except for cerebral atrophy. The patient subsequently experienced acute, fluctuating occipital headaches, predominantly on the right side, which were excruciating and typically nocturnal but not associated with vomiting or loss of consciousness. By May 2024, he developed progressive dysarthria and dysphagia, manifesting as slow speech, nasal voice, and occasional nasal regurgitation. Neurological examination revealed deficits in multiple cranial nerves (III, IV, V, VI bilaterally, VII left, IX, XI, XII), while motor function was intact. Initial investigations, including routine blood work and CSF cytology, returned normal results.

Results: An MRI in August 2024 indicated a 2.9 x 4.5 x 3.2 cm left-sided skull base lesion with several enhancing bony lesions, suggestive of metastasis. Abdominal ultrasound identified a 6.1 x 5.8 cm hypoechoic lesion in the right liver lobe, a 3.4 x 4.1 cm anechoic renal lesion, and prostatomegaly (volume ~36 cc). CECT thorax demonstrated round, hyperdense, mildly enhancing nodules in both lung fields. Due to the suspicion of malignancy, a renal biopsy was performed, and patient was referred for FDG PET/CT which revealed a FDG-avid mass in the prevertebral and left carotid space, hypodense lesions in both kidneys, and soft tissue mass in the left testicle. FDG avid bilateral lung nodules along with mediastinal nodes and a lytic lesion involving sacrum & soft tissue lesion in right humeral region were also noted and were classified as metastasis. Considering the clinical presentation and disease spread, differential diagnoses included disseminated extranodal lymphoma and multifocal paraganglioma, with nasopharyngeal carcinoma deemed less likely due to the absence of suspicious adenopathy. Final renal histopathological examination confirmed high-grade non-Hodgkin lymphoma, specifically diffuse large B-cell lymphoma (DLBCL) with a Ki-67 proliferation index exceeding 90%. The patient is currently being evaluated for chemotherapy.

Conclusions and References: While lymphomas typically present with systemic symptoms and lymphadenopathy, neurological manifestations, particularly multiple cranial nerve palsies, are rare. This case highlights the necessity of including lymphoma in the differential diagnosis of cranial nerve.

Abstract ID: 126: Lupus nephritis associated hemophagocytic lymphohistiocytosis: A rare diagnostic dilemma in a child

N. G. Harrish, Manish Ora, Sanjay Gambhir

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a condition characterized by excessive inflammation, leading to multi-organ failure and often fatal outcomes. It primarily affects infants and young children, with systemic inflammation stemming from abnormal activation of natural killer (NK) cells, CD8+ cytotoxic T-cells, and macrophages. Given this condition’s rarity and non-specific clinical presentation, biochemical examination, biopsy, and imaging play a crucial role in the etiological diagnosis of this disease.

Materials and Methods: A 14-year-old male child presented with symptoms of decreased appetite, swelling over the submandibular region, and uttering during sleep for three months. Renal biopsy showed features of Lupus nephritis membranous type (class V). He had anemia (8.4 mg/dl), thrombocytopenia (124 x 1000/cu.mm), leukopenia (3.52 x 1000/UL), hyponatremia (129 mg/dl) and hypoalbuminemia (3.0 mg/dl). 18F FDG PET/CT was done to work for pyrexia of unknown origin. . It showed diffuse extensive uptake in the bone marrow. Hepatosplenomegaly was noted with liver measuring~ 15.9 cms and spleen~ 12.5 cms along with Hepato-splenic reversal (SUVmax of liver- 1.48 & SUVmax of spleen- 2.20).

Results: A possible diagnosis of diffuse bone marrow pathology such as HLH was raised as there was no evidence of other inflammatory foci or malignancy Blood investigation revealed hyperferritinemia, hypofibrinogenemia, and hypertriglyceridemia. Bone marrow examination revealed increased histiocytes, with few showing hemophagocytosis. HLH diagnosis was established per WHO-2004 HLH diagnostic criteria. The patient was then started on immunosuppressive therapy and responded well to treatment.

Conclusions and References: 18F-FDG PET/CT is a valuable imaging modality for pyrexia of unknown origin. Along with biochemical examinations, it facilitates the established diagnosis of HLH. This case represents a rare case of secondary HLH in a male child suffering from lupus nephritis.

Abstract ID: 132: Evaluating treatment response: SUVmax normalization techniques in FDG PET/CT

Mohd Khalid, Satyanarayan, Satyawati Deswal

Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Evaluating Treatment Response: SUVmax Normalization Techniques in FDG PET/CT.

Objective: This study evaluates the implications and discrepancies of measuring Standardized Uptake Value maximum (SUVmax) normalized to lean body mass (LBM) versus total body weight (BW) in assessing treatment response in patients undergoing Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG PET/CT).

Materials and Methods: An ongoing retrospective analysis was conducted on patients diagnosed with various malignancies who underwent FDG PET/CT before and after treatment. SUVmax values were computed for both LBM and total body weight. The PERCIST criteria were applied to classify patients as having a complete response, partial response, stable disease, or progressive disease. The correlation between the two metrics and clinical outcomes was evaluated using Pearson correlation coefficients and multivariate regression analysis to determine the predictive power of each SUVmax measurement in evaluating treatment efficacy.

Results: A total of 20 patients were included in the analysis, with a median age of 60 years. Seventeen patients exhibited consistent results between SUVmax LBM and SUVmax BW. Discrepancies were noted in three patients: two showed a partial response with SUVmax LBM while being classified as stable with SUVmax BW, and one exhibited progression of disease with SUVmax LBM but stable disease with SUVmax BW. Follow-up findings indicated that SUVmax LBM aligned more closely with clinical outcomes. Notably, SUVmax LBM demonstrated a stronger correlation with treatment response compared to SUVmax BW (r = 0.75 vs. r = 0.58, p < 0.001). Multivariate analysis revealed that SUVmax LBM was an independent predictor of treatment outcome (odds ratio 2.5, 95% CI 1.8-3.6), whereas SUVmax based on BW lost significance after adjusting for confounding factors.

Conclusions and References: This study underscores the importance of incorporating body composition into the evaluation of treatment response using FDG PET/CT. Normalization of SUVmax to lean body mass is suggested to provide a more accurate reflection of metabolic tumor activity, particularly in patients with significant variations in body composition. These findings may enhance prognostic capabilities and improve repeatability in oncology practice.

Abstract ID: 133: Evaluating PET imaging metrics and Ki-67: Implications for breast cancer subtype assessment

Satyawati Deswal, P. Sathya Narayanan, N. Aravind

Department of Nuclear Medicine, DR. RMLIMS, Lucknow, Uttar Pradesh, India

Introduction: Ki-67 is a pivotal biomarker in breast cancer, reflecting cellular proliferation and tumor aggressiveness. 18F-fluorodeoxyglucose (FDG), offer valuable insights into tumor metabolic activity, potentially enhancing our understanding of breast cancer biology. This study aims to explore the relationship between PET imaging parameters and Ki-67 expression in breast cancer patients, alongside key histopathological features.

Materials and Methods: This is an ongoing ambispective study involving patients aged 20-80 with histologically confirmed breast carcinoma, all of whom have not received prior treatment. Ki-67 indices and receptor statuses were determined through immunohistochemistry. All participants underwent standardized 18F-FDG PET scans according to a consistent imaging protocol. We evaluated several parameters, including maximum standardized uptake value (SUVmax), mean SUV, total lesion glycolysis (TLG), metabolic tumor volume (MTV), and surface to lesion glycolysis (STLG). Pearson correlation coefficients and multivariate regression analyses was used to examine the relationships between PET parameters and Ki-67 indices. significance p value was taken as < 0.05.

Results: We included 25 patients with ductal carcinoma (15 luminal and 10 non luminal), with mean age of 58 years. Study revealed significant positive correlations in Luminal subtypes (A and B), particularly with Ki-67 index and primary SUVmax (p = 0.0191), and no statistically significant correlation with SUV mean (p = 0.106), MTV (p = 0.480), TLG (p-0.998) & STLG (p – 1.01)related to the Ki-67 index. In contrast, non-Luminal subtypes (triple-negative and HER2+) showed a positive correlation with MTV (p = 0.026) but no significant associations with TLG (p = 0.97), SUV mean (p = 0.98), or STLG (p = 0.697). These findings suggest that incorporating PET imaging into routine assessments may enhance prognostic evaluations, especially for Luminal subtypes. Further research is ongoing. This finding aligns with a meta-analysis by Surav et al., which reported a moderate correlation between SUVmax and Ki-67 expression. However, it contrasts with a recent study by Mohammadian et al. (2021), which concluded that total lesion glycolysis (TLG) correlates with SUVmax. These discrepancies highlight the need for further research to clarify these relationships.

Conclusions and References: This study reveals there is no significant single absolute quantitative or semi quantitative PET parameter in determining disease severity and multiple factors have to be considered. Further research is needed for routine integration of other PET parameters other than SUV max in assessing severity and for determining response evaluation.

Abstract ID: 141: Role of 18F FDG PET/CT in the management of lymphoma patients after hematopoietic stem cell transplantation – An observational study

Surya Pratap Singh, Manish Ora, H. N. Aftab, Sanjay Gambhir

Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Lymphoma is a type of cancer that affects the lymphatic system. Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for certain types of lymphoma. However, early detection of relapse or progression after HSCT is crucial for optimal management. Positron emission tomography (PET) with fluorodeoxyglucose (FDG) tracer is a sensitive imaging technique that can detect metabolic changes associated with lymphoma. Previous studies have suggested the potential of FDG PET/CT for monitoring post-HSCT lymphoma patients. This study aimed to evaluate the impact of FDG PET/CT on changes in management for lymphoma patients after HSCT. We hypothesized that FDG PET/CT would lead to more frequent and timely changes in management compared to conventional imaging methods.

Materials and Methods: This retrospective observational study analyzed the impact of FDG PET/CT on changes in management for lymphoma patients after HSCT. Twenty patients with lymphoma who underwent HSCT were included (11 hodgkin lymphoma patient and 9 non hodgkin lymphoma patients). Follow-up FDG PET/CT scans were performed, and Deauville scores were assigned to lymphoma lesions. Changes in management were documented based on imaging findings and Deauville scores. The association between changes in Deauville scores and treatment modifications was noted.

Results: Twenty patients with lymphoma who underwent HSCT were followed up with FDG PET/CT scans. Deauville scores were assigned to lymphoma lesions, with 4 patients having a Deauville score III, 9 having a Deauville score IV, and 7 having a Deauville score V. Patients with Deauville scores IV and V required additional cycles of chemotherapy with a change in regimen, while those with a Deauville score III were observed without immediate treatment modifications. These findings suggest that FDG PET/CT with Deauville score assessment can be a valuable tool for guiding treatment decisions in post-HSCT lymphoma patients.

Conclusions and References: This study demonstrates the utility of FDG PET/CT with Deauville score assessment in guiding treatment decisions for post-HSCT lymphoma patients. Patients with higher Deauville scores (IV and V) were more likely to require additional chemotherapy, highlighting the importance of FDG PET/CT in identifying patients who may benefit from intensified treatment.

Abstract ID: 147: FDG PET-CT radiomics features in predicting treatment outcome in Hodgkin’s Lymphoma: Retrospective observational study

P. Sai Sradha Patro, Keertana Kandula, Saitej, Girish Kumar Parida, Kanhaiyalal Agrawal, Prabodha Kumar Das, Sonali Mohapatra

Department of Nuclear Medicine, AIIMS, Bhubaneswar, Odisha, India

Introduction: FDG PET-CT has become integral part of lymphoma staging, response and recurrence evaluation as recommended by Lugano 2014. Baseline staging and response evaluation PET-CT are not only more sensitive and accurate but also has prognostic role in lymphoma management. In Lugano, 5 point scoring system (Deauville score-DS) for response assesment on PET CT was suggested to standardise the reporting system worldwide. Interim PET CT DS has prognostic impact for final response while baseline PET-CT SUVmax cannot predict the treatment outcome. Delta SUV (percentage change in SUVmax in interim and baseline PET-CT) has shown prognostic role in lymphoma response evaluation. Recent studies on radiomics features from PET-CT in lymphoma patients have shown promising role as a prognostication tool. Further studies on this is needed to further validate ist use in routine clinical use.

Aim: To study the utility of baseline 18 F FDG PET-CT radiomics features in predicting treatment response in Hodgkins Lymphoma.

Objectives: Primary: To find correlation between baseline FDG PET-CT radiomics features and response to treatment in patients with Hodgkins Lymphoma. Secondary: 1. To find correlation with other response assesment parameters like Deauville score and Delta SUVmax with baseline texural features on FDG PET-CT. 2. To find correlation between baseline FDG PET-CT texural features with the initial stage of Hodgkins Lymphoma.

Materials and Methods: All the patients with diagnosed Hodgkin’s Lymphoma who underwent staging and response evaluation 18 F FDG PET-CT within the study period (2022-2024) were analysed (30 patients). Baseline PET-CT radiomics features were extracted from the lymph nodal station with highest SUVmax for each patients using LIFEx software. Interim and post chemotherapy completion PET-CT Deauville Score (DSI, DSF), Delta SUVmax in interim PET-CT and PERCIST response criteria for interim and final response were evaluated. Correlation of various response criteria’s and stage with baseline PET-CT radiomics features were analysed.

Results: The various radiomics parameters showed correlation with the initial stage of lymphoma, Delta SUVmax and final response.

Conclusions and References: 18F FDG PET-CT derived radiomics features can be helpful in predicting the stage of Hodgkin’s Lymphoma and response to treatment, hence can be used as a prognostication tool.

Abstract ID: 153: Unveiling hidden trails: The crucial role of FDG PET CT scan in detecting rare pathologies like B cell acute lymphocytic leukemia in a young girl presented with PUO

Kartikey P. Solanki, M. G. Vishnoi, Anurag Jain, Dharmesh Paliwal

Armed Forces Medical Services, Visakhapatnam, Andhra Pradesh, India

Introduction: Haematological malignancies presenting as Pyrexia of Unknown Origin (PUO) are relatively rare but important to recognize. Herein, we describe a case of PUO revealing B-cell Acute Lymphoblastic Leukaemia (B-ALL) in a young girl. Advanced imaging techniques like FDG PET CT scan emerge as indispensable tools, offering unparalleled insights into the underlying pathophysiology. This report elucidates the invaluable role of FDG PET CT in elucidating a complex case, to know extent of disease, guiding site of biopsy, deciding treatment protocol and response assessment.

Materials and Methods: A 19-year-old girl was admitted with a perplexing constellation of symptoms, including intermittent fever, generalized body ache, significant weight loss and anorexia. Physical examination revealed pallor, pedal edema, but no icterus, clubbing, cyanosis, or lymphadenopathy. Vital signs were stable. Despite exhaustive investigations, including routine laboratory tests, infective etiology workup, and imaging studies, the underlying cause remained elusive. 18 F FDG PET CT scan revealed diffusely increased tracer uptake in the axial and appendicular skeleton, along with FDG avid lytic lesions in bilateral pelvic bones and patchy bone marrow uptakes in the distal appendicular system. Notably, bone and marrow abnormalities detected on FDG PET CT scan imaging prompted further evaluation, leading to the discovery of a hypercellular bone marrow infiltrated with blastoid cells positive for PAX5, CD20, and CD34, indicative of B-cell Acute Lymphoblastic Leukemia (B-ALL). This comprehensive imaging assessment not only delineated the extent of disease involvement but also provided crucial guidance for therapeutic decision-making. The patient was promptly initiated on appropriate management, highlighting the pivotal role of FDG PET CT in expediting diagnosis and facilitating timely intervention.

Results: B-ALL is a rare cause of PUO, especially in young patients. Early recognition and treatment are essential for improving outcomes in patients with B-ALL presenting with PUO. PET CT scan plays a crucial role in assessing disease extent and guiding management. PET guided bone marrow aspiration and biopsy provided diagnostic result in above case.

Conclusions and References: This case underscores the importance of considering haematological malignancies, including B-ALL, in the differential diagnosis of PUO, particularly when accompanied by cytopenia and bone abnormalities. This case epitomizes the transformative impact of 18F FDG PET CT scan in diagnosing rare and elusive pathologies, particularly in the context of PUO. By providing a comprehensive visualization of disease burden, FDG PET CT enables clinicians to navigate diagnostic challenges with precision and confidence. Moreover, its ability to guide targeted interventions underscores its indispensable role in modern clinical practice.

Abstract ID: 172: Role of 18F-FDG PET-CT in diagnosing a rare case of primary cutaneous posttransplant lymphomatous disorder

Nibrittee Deka, Vikram Lele, Nusrat Shaikh

Jaslok Hospital and Research Center, Mumbai, Maharashtra, India

Introduction: Post-transplant lymphoproliferative disorder (PTLD) is an uncommon complication after solid organ transplants and hematopoietic stem cell transplants with an annual incidence of 0.5% to 3.7%. The incidence of PTLD with multiorgan/intestinal transplants is most frequent due to the more aggressive immunosuppressive therapy and kidney transplant being the least frequent. The PTLD rate is higher during the first year post-transplant and lower in subsequent years. Isolated involvement of the skin without systemic involvement in PTLD is rare. Primary cutaneous PTLD is generally categorized as either cutaneous T-cell lymphomas (PT-CTCL) or cutaneous B-cell lymphomas (better and worse outcomes for B cell PTLD and T cell PTLD, respectively), with variable Epstein-Barr virus (EBV) positivity. PT-CTCL remains an infrequent malignancy, representing approximately 5% of PTLD cases involving the skin. PTLD is mainly caused by Epstein–Barr virus infection (early onset PTLD) and excessive immunosuppression (late onset PTLD) and therefore, minimizing the dose of immunosuppressive agents and prophylactic antiviral therapy with acyclovir and ganciclovir may reduce the incidence of PTLD. Factors associated with poor prognosis include advanced age, extra nodal lesions, T-lymphocyte phenotype, tumor monoclonal nature and late clinical staging.

Materials and Methods: 4.45 mCi of 18F-FDG is injected intravenously to patient after 6 hours of fasting. After 60 mins of injection, patient was scanned on dedicated 16 slice PET – CT (GE –Discovery IQ 5 ring scanner). Standard uptake values (SUV) normalized to body weight obtained over lesions. Finger prick blood glucose level at the time of injection was 80 mg/dl. Contrast CT scan was acquired as part of PET CT protocol on a multislice CT with 1.2 mm slice thickness.

Results: High grade metabolically active multiple nodular cutaneous and subcutaneous soft tissue thickening seen involving the right half of face (SUVmax: 8.2), right iliac fossa (SUVmax: 8), right calf (SUVmax: 15), left mons pubis (SUVmax: 7) and the soft tissue thickening and fat stranding surrounding the transplant kidney appearing suspicious for post-transplant associated lymphomatous disorder.

Conclusions and References: FDG PET/CT is beneficial in the diagnosis of patients with PTLD since it can detect occult lesions not identified on other imaging modalities, particularly extranodal lesions and may predict the PTLD subtype, as the lesions with higher pathologic grade presents with significantly higher SUVmax compared with the less aggressive forms.

Abstract ID: 174: Neurolymphomatosis in high-grade large B-cell lymphoma: Diagnostic utility of PET-CT in identifying rare cranial and peripheral nerve involvement

Dharmesh Paliwal, M. G. Vishnoi, Neeraj Sharma, K. P. Solanki, P. B. Mukherjee, Amit Sharma

Department of Nuclear Medicine, Command Hospital (SC), Pune, Maharashtra, India

Introduction: Non-Hodgkin’s Lymphoma (NHL) is a diverse group of hematologic malignancies, with diffuse large B-cell lymphoma (DLBCL) being the most common aggressive subtype. Neurolymphomatosis (NL), a rare complication of lymphoma, involves direct infiltration of peripheral nerves by malignant lymphoid cells. This case aims to highlight the presentation and diagnostic approach of a 73-year-old male with DLBCL complicated by neurolymphomatosis, using PET-CT as a critical tool for diagnosis and management.

Materials and Methods: A 73-year-old male, initially diagnosed with high-grade DLBCL after presenting with low-grade fever, painful cervical lymphadenopathy, and systemic symptoms, was treated with six cycles of R-CHOP chemotherapy from January to May 2024. Initial PET-CT (29.12.2023) revealed FDG-avid lymphadenopathy and pleural deposits on both sides of the diaphragm. The patient developed diplopia in April 2024, which improved with treatment, and an interim PET-CT (12.04.2024) showed residual FDG avidity in cervical nodes and a mildly avid pulmonary nodule. Post-chemotherapy PET-CT (19.07.2024) detected FDG-avid pleural nodules and retropharyngeal uptake, raising suspicion of neurolymphomatosis. The patient was kept under close follow-up until October 2024 when he developed progressive neurological symptoms, including right upper limb weakness, left-sided headache, and tinnitus. A PET-CT scan (05.10.2024) was performed to evaluate the progression and revealed FDG avid thickenings in multiple cranial and peripheral nerves, along with FDG avid cervical and abdominal lymphadenopathy. MRI revealed subtle thickening of the cavernous sinus and sacral nerve roots, raising suspicion of neurolymphomatosis.

Results: The PET-CT findings demonstrated extensive FDG-avid involvement of multiple cranial (oculomotor, abducens, vagus, and auriculotemporal) and peripheral nerves (axillary, femoral, sciatic), as well as lymph nodes, confirming the spread of disease along neurovascular structures, indicative of neurolymphomatosis. MRI supported these findings with evidence of nerve root thickening. The combination of imaging modalities confirmed the diagnosis of NL, a rare manifestation of DLBCL.

Conclusions and References: This case highlights the utility of PET-CT in diagnosing and monitoring neurolymphomatosis, an uncommon but severe complication of DLBCL. PET-CT allows for the identification of FDG-avid neuroinvolvement, crucial for early diagnosis and intervention. Prompt recognition and targeted management may improve patient outcomes in cases of neurolymphomatosis.

Abstract ID: 175: Utility of early dynamic 18F-fluorodeoxyglucose positron emission tomography in evaluation of hepatic lesions

Kuldeep Vala, Madhur Kumar Srivastava

NIMS, Hyderabad, Telangana, India

Introduction: Differentiating malignant from benign hepatic lesions can be challenging. Current standard modalities such as CECT sometimes may be unsuitable in properly diagnosing & characterising liver lesions. The role of FDG PET/CT in the diagnosis of HCC is controversial particularly in view of the limited sensitivity of the technique in well-differentiated HCCs. Performing early dynamic (ED) liver 18F-FDG PET/CT before the conventional static WB procedure could provide an alternative for detecting HCC hypervascularization in patients with contraindications to CE morphologic imaging.

Objective: Primary objective of the current study is to assess the diagnostic utility of Early Dynamic 18-FDG Liver PET CT with delayed static whole body PET CT scan in evaluation of hepatic lesions when correlated with HPE diagnosis.

Materials and Methods: Prospective, observational study design. A sample size of ~22 patients. Early Dynamic FDG PET/CT (4 minutes) with conventional static whole body imaging will be performed using GE Discovery 710 PET-CT machine. Endpoints are summarised in following tables.

Results: Provided in tabular format in the uploaded word document.

Conclusions and References: The addition of Early dynamic 18F-FDG PET CT to delayed whole-body PET CT imaging significantly increases the diagnostic accuracy of the scan & it might replace/supplement established CE morphological imaging for hepatic lesions evaluation.

Abstract ID: 194: Role of 18-fluorodeoxyglucose positron emission tomography metabolic radiomics in predicting treatment response in patients with nonsmall cell lung cancer

Pratheek N. Prasanth, Mudalsha Ravina, Ranganath T. Ganga, Amit Kumar, Aravind Kumar Shukla, Rutuja Kote

Department of Nuclear Medicine, AIIMS, Raipur, Chhattisgarh, India

Introduction: Lung cancer accounts for 5.9% cancer cases and 8.1% cancer-related deaths in India. At the time of presentation, most patients have locally advanced or metastatic disease. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) plays a crucial role in staging and evaluating treatment response in such patients. Nearly 1/3rd of lung cancer patients who received chemotherapy will have disease progression and hence there is a need for advanced imaging techniques like PET-CT to monitor treatment response. Currently there is no definitive imaging modality that can predict the pre-therapy probability of response to treatment. The concept of textural analysis is based on spatial arrangement and distribution of voxels in a volume of interest. It characterizes tumor heterogeneity in the form of PET image-derived quantitative indices. These indices could be used in predicting therapy response which will help in guiding treatment decisions.

Aims: To investigate the role of 18-FDG PET/CT radiomic features and texture analysis parameters in predicting therapy response in patients of Non-Small Cell Lung Cancer (NSCLC) who received chemotherapy, using post-therapy 18-FDG PET/CT scan as the reference standard.

Materials and Methods: Ambispective analysis of the data of biopsy proven patients of NSCLC who underwent baseline 18-FDG PET/CT PET-CT and post-therapy 18-FDG PET/CT scan after a minimum of 4 cycles of chemotherapy was done. Radiomic features and texture analysis parameters were derived from pre-treatment baseline 18-FDG PET/CT scan using Local Image Feature Extraction (LIFEx) software version 7.0. Obtained parameters were entered in Microsoft Excel spreadsheet and analyzed using Statistical Package for Social Sciences (SPSS) software version 21.0.

Results: A total of 70 patients were included in the study. On the basis of their response to chemotherapy, patients were divided into ‘responders’ group and ‘non-responders’ group using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST Criteria). Among them 42 patients were responders and 28 patients were non-responders. Four textural analysis parameters turned out to be significant in the prediction of disease progression & cutoff values were calculated for these parameters according to the ROC curves: Grey Level Co-occurrence Matrix (GLCM)_Correlation, GLZLM _LZHGE (Gray Level Zone Length Matrix Large Zone High Grey Level Emphasis), Discretized_Energy and SHAPE_Compacity.

Conclusions and References: Textural analysis parameters could provide prognostic information and guide treatment decisions in NSCLC patients and possibly in other malignancies as well. Larger multicentric studies are needed for better insight.

Abstract ID: 206: Optimizing staging and posttherapy assessment in breast cancer: Added value of diffusion-weighted imaging in hybrid whole-body 18F-FDG PET/MR imaging

Shibiraj Patel, P. Sundaram

Amrita Institute of Medical Sciences, Ahmedabad, Gujarat, India

Introduction: Breast cancer is the most prevalent cancer among women, underscoring need for early and accurate diagnosis. Hybrid FDG PET/MR combines metabolic and anatomical imaging, improving diagnostic precision. Diffusion-Weighted Imaging (DWI) has gained prominence for differentiating benign and malignant lesions without contrast agents. However, studies integrating DWI and PET images are limited, as most previous research utilized separate PET and MRI systems on different days.

Aims and Objectives: To investigate correlation between SUVmax and ADCmean/ADCmin values in primary and metastatic breast cancer lesions using hybrid PET/MR. To determine added diagnostic accuracy of DWI for regional and distant metastasis detection, comparing findings with FDG PET/CT. To establish optimized SUVmax and ADC cutoff values for distinguishing malignant from benign lesions.

Materials and Methods: This retrospective observational study included 26 biopsy confirmed breast cancer patients, 5 for initial staging and 21 for post-therapy follow up. All patients underwent hybrid PET/MRI exams between December 2021 and August 2024, receiving 0.1 mCi/kg of 18F-FDG intravenously. ADC (ADCmean and ADCmin), and SUVmax were recorded for each FDG-avid lesion.

Results: A statistically significant linear inverse correlation was observed between mean SUVmax and mean ADCmean/ADCmin values across all primary and metastatic lesions, as demonstrated by correlation analysis. Sensitivity, specificity, PPV, and NPV were calculated and compared with SUVmax and ADCmean values. ROC curves generated and AUC analysis was performed to establish optimal cutoff points for differentiating malignant from benign lesions. IHC revealed 4 ER-positive, 6 Luminal B, 7 triple-negative (one PD-L1 positive), and 6 HER2-positive cases, which were compared with above parameters. While FDG PET demonstrated greater accuracy in evaluating regional lymph node metastases, the negative findings of DWI/ADC and biopsy in four patients suspected of mediastinal lymph node metastases on FDG PET (Average SUVmax of 4.1), reinforced the reliability of combined DWI and PET imaging. Notably, DWI showed a strong ability to detect brain metastases and pulmonary nodules.

Conclusions and References: Our study demonstrated correlation between SUVmax and ADC values, underscoring the complementary roles of FDG PET and DWI in breast cancer assessment. As most prior research has relied on separate PET and MRI systems, often conducted on different days, our study fills a critical gap by demonstrating the benefits of simultaneous imaging. By exploring utility of DWI and ADC values we aim to enrich understanding of hybrid PET/MR’s potential in breast cancer diagnostics.

Abstract ID: 38: Design of 99mTc analogue of DUPA PSMA inhibitor for its potential use in prostate cancer imaging

Navin Sakhare^1,2, Anupam Mathur^1,2, Shubhangi Mirapurkar¹,G. Rani¹, M. Sheela¹, Shalaka Paradkar¹, Arpit Mitra¹, Usha Pandey¹

¹Radiopharmaceuticals Program, Board of Radiation and Isotope Technology, Navi Mumbai, Maharashtra, ²Department of Chemistry, Mangalore University, Mangalore, Karnataka, India

Introduction: 68Ga-PSMA-11 is an established PET radiotracer that is in use in clinics for prostate cancer imaging. Currently, there is a surge in the development of new diagnostic tracers with improved pharmacokinetics for prostate cancer imaging. The present work attempts to develop a new tracer that is suitable for 99mTc SPECT imaging. DUPA (2-[3-(1,3-dicarboxy propyl) ureido] pentanedioic acid) ligand is a known PSMA enzyme inhibitor that targets PSMA receptor found overexpressed on prostate cancer. The present work synthesizes and evaluates a 99mTc “metal essential” glutamate complex based on [99mTc≡N]2+ (Technetium nitride) core which mimics DUPA ligand (glutamic acid-urea-glutamic acid) for PSMA targeting.

Materials and Methods: L-Glutamic acid and succinic dihydrazide (SDH) were procured from TCI, Japan. Glutamate precursor (Glutamate-DTC) was synthesized prior to 99mTc labeling. Briefly, Glutamic acid (0.5 g; 3.4 mmol) was dissolved in absolute ethanol (20 mL) in presence of sodium carbonate (1.1 g; 10.2 mmol) and reacted overnight at room temperature with excess carbon disulphide (1 mL, 17 mmol). The crude product was then analyzed by ESI-MS and directly used for labelling with [99mTc≡N]2+ core. [99mTc≡N]2+ core was generated on reaction of [99mTcO4]- (10 mCi) with SDH (5 mg) in presence of SnCl2 at room temperature. To this intermediate, glutamate-DTC (0.1 g) was added and the reaction mixture was incubated at room temperature to yield the final complex, which was characterized by TLC and HPLC. The complex was then bio-evaluated in vitro in PSMA positive LNCaP cell lines.

Results: Glutamate-DTC was synthesized in ~60% yield. The radiolabelling of this ligand with [99mTc≡N]2+ core yielded final complex in more than 96% purity. In vitro studies showed increased uptake of 99mTc-complex in LNCaP cells (~9.5%ID/106 cells @ 2 h) in comparison to 177Lu-PSMA-617 (~5%ID/106 cells), however the specificity observed was only 65% (vs 90% for177Lu-PSMA-617) as ascertained from inhibition using 2-PMPA.

Conclusions and References: A DUPA 99mTc mimic was successfully synthesized in moderate yields. In vitro results indicated partial recognition of 99mTc≡N as a substitute for urea pharmacophore required for PSMA targeting. Efforts are underway to screen the in vivo behavior of the synthesized complex in tumor model.

Abstract ID: 52: Comparison of absolute quantification and %QLU of 99mTc-PSMA with SUVmax of 68Ga-PSMA in patients with primary prostate cancer

Monika Hooda, Komalpreet Kaur¹, Ajay Chitkara¹, Ravimohan Mavuduru², Aditya Prakash², Harmandeep Singh¹, S. K. Singh², Nandita Kakkar³, Baljinder Singh¹

Postgraduate Institute of Medical Education and Research, Departments of ¹Nuclear Medicine, ²Urology and ³Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Introduction: Prostate cancer (PCa) is the most prevalent non-cutaneous malignancy and the sixth foremost cause of cancer mortality among men globally. Prostate Specific Membrane Antigen (PSMA) has been established as a highly significant molecular marker in prostate cancer (PCa). 68Ga-PSMA-PET is the standard molecular imaging technique for prostate cancer patients, as PSMA is overexpressed on the surface of prostate cancer cells. The correlation of quantitative parameters (absolute quantification and semi-quantitative) of 99mTc-PSMA with SUVmax of 68Ga-PSMA for the primary lesion of PCa.

Materials and Methods: Ten (n = 10, mean age 67 ± 8.08) male patients with histologically confirmed prostate carcinoma were included in the study. All the patients underwent prior 68Ga-PSMA PET/CT (DISCOVERY 710 PET/CT, GE, Milwaukee, USA) followed by 99mTc-PSMA (whole body and regional SPECT/CT) imaging within one week. Thereafter both the scans were reconstructed. Further, the correlation between the SPECT and PET based quantitative parameters for primary lesion i.e. absolute quantification & SUVmax and % quantitative lesion uptake (%QLU) and SUVmax for the matched PSMA avid lesions detected on both the modalities was evaluated.

Results: The mean PSA levels were found out to be 68.26 ± 91.59 ng/mL. Median Gleason score was 4.0+3.0 and the International Society of Urological Pathology (ISUP) grade was 3.0. On 10 primary lesions detected on both the modalities, the mean SUVmax was 22.66 ± 25.74, mean absolute quantification values was 31.73 ± 35.04, mean %QLU was evaluated to be 25.96 ± 24.24. A highly significant correlation of absolute quantitative with the SUVmax and %QLU with SUVmax values was noted to be r=0.975; p <0.001 and r=0.983; p <0.001 respectively.

Conclusions and References: 99mTc-PSMA SPECT/CT imaging offers a competitive technique to 68Ga-PSMA PET/CT for disease evaluation and response assessment to PSMA based radionuclide therapies in primary as well as metastatic PCa patients, when 68Ga-PSMA PET/CT is not available.

Abstract ID: 67: Machine learning using PSMA PET radiomics predicts high-risk ISUP grade groups in treatment-naïve prostate cancer patients

Aman Tilak, Bangkim Chandra Khangembam, M. Kavin, Asem Rangita Chanu, Ritwik Wakankar, Aman Tilak, Seema Kaushal, Amlesh Seth, Chandan Jyoti Das, Chetan Patel, Rakesh Kumar

Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Introduction: This study assesses the feasibility of machine learning (ML), using PSMA PET radiomics, to predict high-risk ISUP grade groups in treatment-naïve prostate cancer patients.

Materials and Methods: Data from pathologically confirmed treatment-naïve prostate cancer patients who underwent 68Ga-PSMA-11 PET/CT between January 2018 and August 2024 were analyzed. The primary outcome was the identification of ISUP grade group ≥4, based on pathology. Key PET/CT parameters, including primary lesion characteristics (localization, visual score, multifocality, laterality) and disease extent (N1, ≥T3), were collected. Radiomics features were extracted from whole prostate regions of interest, and Combat Harmonization was applied to minimize batch effects. A total of 112 clinico-imaging and radiomics features were analyzed. A bootstrapping approach allocated 189 patients (January 2018 – December 2023) to the training set, with 75 patients reserved for validation. An independent cohort of 66 patients (January 2023 – August 2024) was used for testing. Feature selection was performed using the Gini Index, and 10 ML algorithms were trained via stratified 10-fold cross-validation. After validation, model evaluation for generalizability was tested on the unseen testing set. Model performance was evaluated using Area Under the Curve (AUC), classification accuracy (CA), F1 score, Precision, and Recall, while SHAP (SHapley Additive exPlanations) values provided insights into model interpretability displayed as Beeswarm SHAP plots.

Results: The study included 255 male patients (mean age: 67.6 ± 8.7 years). High-risk ISUP grade groups were present in 65.1% (123/189) of the training/validation set and 62.1% (41/66) of the testing set (P = 0.766). Eight ML algorithms achieved >0.800 performance metrics during cross-validation, with Gradient Boosting (catboost) showing the best results (AUC 0.953, CA 0.878, F1 score 0.913, Precision 0.910, Recall 0.917). During validation, seven ML algorithms maintained >0.700 in all metrics, with Random Forest achieving the best AUC of 0.795. Seven models in the independent test set maintained strong performance (>0.700 in all metrics with various Gradient Boosting models achieving AUC >0.800). Beeswarm SHAP plot analysis highlighted interpretable decision patterns in the Gradient Boosting (xgboost), Gradient Boosting (scikit-learn), and Random Forest models, with Gradient Boosting (xgboost) achieving the highest performance metrics (AUC 0.812, CA 0.803, F1 score 0.840, Precision 0.850, and Recall 0.829).

Conclusions and References: Machine learning utilizing PSMA PET radiomics can predict high-risk ISUP grade groups in treatment-naïve prostate cancer patients, with robust performance and generalizability that support clinical applicability. SHAP analysis offered valuable insights into the decision-making processes of both Gradient Boosting and Random Forest models.

Abstract ID: 80: Prediction of high-very high NCCN risk in treatment-naïve prostate cancer patients using PSMA PET radiomics-based machine learning

Aman Tilak, M. Kavin, Bangkim Chandra Khangembam, Asem Rangita Chanu, Ritwik Wakankar, Seema Kaushal, Amlesh Seth, Chandan Jyoti Das, Chetan Patel, Rakesh Kumar

AIIMS, New Delhi, India

Introduction: The aim of this study is to evaluate the efficacy of machine learning (ML) based on PSMA PET radiomics to predict high-very high NCCN risk in treatment-naïve prostate cancer patients.

Materials and Methods: Data from pathologically confirmed treatment-naïve prostate cancer patients who underwent 68Ga-PSMA-11 PET/CT between January 2018 and August 2024 were analyzed. The target outcome was high-very high NCCN risk. PET/CT-derived parameters, including primary lesion localization, visual score, multifocality, laterality, and presence of N1 disease, were collected. Radiomics features were extracted from primary lesion segmentations using whole prostate regions of interest. Sampling with Bootstrapping allocated 189 patients from January 2018 to December 2023 to the training set, with 75 patients reserved for validation. A separate dataset of 66 patients, enrolled between January 2023 and August 2024, was used for testing. A total of 110 clinico-imaging and radiomics features were analyzed, with Combat Harmonization applied to the radiomics features to reduce batch effects. Feature selection was performed using the Gini Index, and 10 ML algorithms were trained using stratified 10-fold cross-validation. Validation was performed on the validation set while model generalization was assessed on the testing set with their Area Under the Curve (AUC), classification accuracy (CA), F1 score, Precision, and Recall. Model interpretability was assessed using SHAP (SHapley Additive exPlanations) values displayed as Beeswarm SHAP plots.

Results: The study included 255 male patients with a mean age of 67.6 ± 8.7 years. High-very high NCCN risk was observed in 142/189 (75.1%) of patients in the training/validation sets and 40/66 (60.6%) in the testing set (P = 0.028). Seven ML algorithms achieved >0.800 in all the performance metrics during cross-validation, with k-Nearest Neighbors (kNN) performing the best (AUC 0.964, CA 0.926, F1 score 0.951, Precision 0.957, Recall 0.944). On validation, kNN still achieved the highest AUC of 0.785. Testing on the independent dataset showed seven ML models maintained strong performance (AUC >0.700). Three models depicted a clear pattern of model interpretability based on the Beeswarm SHAP plots. These were Gradient Boosting (xgboost) Gradient Boosting (scikit-learn), and Random Forest. Among these, Gradient Boosting (xgboost) had the highest AUC of 0.782, with CA 0.712, F1 score 0.782, Precision 0.723, and Recall 0.850 respectively.

Conclusions and References: Machine learning using PSMA PET radiomics can predict high-very high NCCN risk in treatment-naïve prostate cancer patients. SHAP analysis provided insights into model decision-making for Gradient Boosting and Random Forest models.

Abstract ID: 182: Imaging prostate cancer with 99m Tc MDM imaging

Vandana K. Dhingra, K. Vidhya, Meena Negi, Puja Hazari¹, Ankur Mittal, Sandeep Basu², Anil Kumar Mishra³, Manoj Gupta

Department of Nuclear Medicine, AIIMS, Rishikesh, ³IIT, Roorkee, Uttarakhand, ¹INMAS, DRDO, Delhi, ²RMC, BARC, Mumbai, Maharashtra, India

Introduction: Prostate cancer research is advancing due to increased incidence and longer life expectancy. Enhanced diagnostics and therapies are essential for improving patient quality of life. Tumor cells depend on amino acids for growth, making amino acid-based imaging probes (like MDM) a promising tool for targeted detection.

Aims and Objectives: This study evaluates Tc-99m MDM imaging in prostate cancer patients, focusing on uptake patterns and abnormal uptake in primary tumors and metastases. It also aims to assess physiological uptake and the labeling efficiency of locally prepared MDM kits.

Materials and Methods: Patients with prostate cancer referred for Tc-99m MDM underwent early and delayed whole-body planar and SPECT/CT imaging of the pelvis. Images were analyzed for physiological distribution and abnormal uptake. Tc-99m (15-20 mCi) was added to thawed MDM vials, incubated for 20 minutes, filtered, and underwent quality control via paper chromatography.

Results: In early imaging, MDM predominantly accumulates in the kidneys and drains into the urinary bladder, reflecting the genitourinary excretion route. Delayed imaging shows nearly complete washout of the radiopharmaceutical from the kidneys. Qualitative and semiquantitative analyses were performed, assessing organ-to-background uptake ratios. Uptake in the prostate was classified into three grades: 0 and 1 represented mild uptake (equal to or below background), while grade 2 indicated uptake above background. Uptake was also evaluated in known metastatic sites, such as lymph nodes and bones. However, there was no significant correlation between uptake and PIRADS scores for MDM. Among the 50 patients who underwent MDM imaging, 38% were found to have metastatic disease, and 22% exhibited prostatic uptake. Most patients demonstrated grade 0 uptake (approximately 78%), followed by grade 1 (18%) and the least, grade 2 (4%). Notably, all patients with metastasis—whether in bones or lymph nodes—showed grade 0 uptake at known metastatic sites. All doses were injected only after passing quality control (QC), confirming purity levels exceeding 96% for MDM, ensuring reliability for imaging results.

Conclusions and References: This study is the first to evaluate Tc-99m MDM in prostate cancer patients. While some patients with high Gleason scores exhibited uptake, overall performance in amino acid imaging was poor. There is a growing need for additional research with larger patient cohorts in the field of radionuclide imaging.

Abstract ID: 215: Head-to-head comparison of 68Ga-PSMA PET/CT and 99mTc-MDP bone scintigraphy for the detection of bone metastases in patients with prostate cancer: The experience in a tertiary care center

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

CMC, MGR University, Vellore, Tamil Nadu, India

Introduction: To compare the diagnostic performance of 68Ga-PSMA PET/CT with that of 99mTc-MDP bone scan (BS) for the detection of bone metastases in patients with Prostate cancer.

Materials and Methods: Retrospective analysis of patients diagnosed with Prostate cancer with bone metastases from July 2016 to January 2024 done. Patients who had both 68Ga-PSMA PET/CT and 99mTc-MDP BS (within a period of 4 weeks and no intervention between the studies) were included. Uptake in bone lesions in both PSMA PET/CT and BS in each patient were recorded and compared. Correlation with clinical symptoms, radiological imaging, s.ALP and PSA levels and post treatment assessment done.

Results: Of 379 who had 68Ga-PSMA PET/CT and 99mTc-MDP in this period, 38 patients aged 52 to 80 years who underwent both scans within a span of 30 days were included. Both were negative in 19. Remaining patients showed bone metastases:

• ● Both 99mTc-MDP BS and 68Ga-PSMA PET/CT positive: 9.

• ● Only 99mTc-MDP bone scan positive: 5 (all were false positives).

• ● Only 68Ga-PSMA PET/CT positive: 5.

Conclusions and References: The diagnostic performance of 68Ga-PSMA PET/CT is superior for the detection of Prostate cancer bone metastases. 99mTc-MDP BS is not additive to PSMA PET in identifying bone metastases and serves as potential stand-alone test for Prostate cancer.

Abstract ID: 219: Whole body 99mTc-PSMA and regional SPECT quantitative lesion uptake values provides comparable detection efficiency and positive correlation with 68Ga-PSMA PET/CT based SUVmax parameters in metastatic prostate cancer patients

Monika Hooda, Sarika Prashar¹, Komalpreet Kaur¹, Ajay Chitkara¹, Ravimohan Mavuduru², Aditya Prakash², Harmandeep Singh¹, S. K. Singh², Nandita Kakkar³, Baljinder Singh¹

Postgraduate Institute of Medical Education and Research, Departments of ¹Nuclear Medicine, ²Urology and ³Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Introduction: In this study, the diagnostic performance of 99mTc-PSMA was compared with the ‘standard of care’ 68Ga-PSMA imaging for the detection efficiency for the primary and metastatic lesions in PCa patients. The correlation between the semi-quantitative parameters i.e. the percentage quantitative-lesion uptake (%QLU-SPECT) and (SUVmax -PET) was also evaluated. The utility of 99mTc-PSMA in PCa as a cost-effective substitute for 68Ga-PSMA has been reported.

Materials and Methods: Twenty-one (67±8.02 yr) patients with histologically proven PCa were included. All the patients underwent 68Ga-PSMA followed by 99mTc-PSMA within one week. Freshly prepared 99mTc-PSMA was injected (mean radioactivity = 491.36 ± 79.55 MBq) intravenously. The whole body (2 h & 4 h) and regional SPECT/CT (3 h) of the suspected sites were acquired. The PET detected PSMA avid lesions were analysed for the estimation of SUVmax values. The comparative data analysis included the number of metastatic lesions detected on 99mTc-PSMA in comparison to 68Ga-PSMA PET/CT imaging. Further, the correlation between the SPECT and PET based quantitative parameters i.e. % quantitative lesion uptake (%QLU) and SUVmax for the matched PSMA avid lesions detected on both the modalities was also evaluated. The method for SPECT based quantitative analysis has been described.

Results: The mean PSA levels were found out to be 62.0±154.21 ng/mL. Median Gleason score was 4.0+3.0. Both the techniques detected PSMA avid lesions in 20/21 patients. 68Ga-PSMA PET/CT detected a total of 137 (6.85 lesions/patient) metastatic lesions (39 pelvic lymph nodes; 32 distant lymph nodes; 66 skeletal lesions). On the comparative analysis, 99mTc-PSMA detected 31/39 pelvic lymph nodes; 29/32 distant lymph nodes; 64/66 skeletal lesions (124/20=6.2 lesions per patient). On 57 matched lesions (20 primary; 12 lymph nodes and 25 skeletal lymph nodes) detected on the both the modalities, the semi-quantitative analysis provided mean % QLU of 7.17 ±10.64 and mean SUVmax of 17.91±12.14. A highly significant correlation (r=0.516; p <0.001) was noted with the SUVmax values.

Conclusions and References: With the comparative detection efficiency (92.0%; 144/157 lesions) of 99mTc-PSMA as compared with 68Ga-PSMA PET/CT and highly significant positive correlation (r=0.516; p <0.001) between %QLU and SUVmax, 99mTc-PSMA may be used as an alternative technique.

Abstract ID: 142: Clinical utility of F18 NOTA NOC PET-CT in neuroendocrine tumor

Naveen Yadav

SMS Medical College, Jaipur, Rajasthan, India

Introduction: SSTR PET imaging plays a very important role in the management of neuroendocrine tumours (NETs). Gallium 68 SSTR labeled radiopharmaceutical is used as standard for SSTR imaging. However they are produced from 68Ge/68Ga generators which is not widely available because of high cost and short half life. These challenges can be overcome by F18 labeled alternatives due to its long half-life and feasibility by production and supply from faraway available cyclotron. Limited studies are available to evaluate the clinical application of F18 NOTA NOC in NETs.

Aim: To evaluate the clinical utility of F18 NOTANOC PET-CT in neuroendocrine tumors.

Materials and Methods: 29 Patients with histologically proven NETs were analysed from Oct 2023 to Sept 2024. Patients were injected 4-5 MBq/kg body weight of F18 AIF NOTA Octreotide. PET-CT was performed 1 hour after intravenous injection. All patients were biopsy proven for neuroendocrine neoplasms. NOTANOC uptake was evaluated by distribution and measuring the SUVmax of target lesions for various indications like diagnosis, staging, restaging, response evaluation and residual/recurrence in NETs.

Results: A few cases showing the clinical uses in various conditions are shown in the figures. The Table shows the NETs origin from various sites.

Conclusions and References: This study concludes that F18 NOTA NOC is a cost-effective and easily available PET radiopharmaceutical for functional imaging in neuroendocrine tumor.

Abstract ID: 165: Fibroblast activated protein inhibitor aided diagnosis and therapy: Revolutionizing precision medicine

Sejal Chopra, Jaya Shukla, Yamini Mathur, Frank Roesch, Euy Sung Moon, R. N. Naga Santhosh Irrinki, Rama Walia, Ajay Duseja, Bhagwant Rai Mittal

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: Various FAP inhibitors (FAPi) DOTA.SA.FAPi (SA.FAPi), DATA5m.SA.FAPi (5m.FAPi), DATA5m.C4.FAPi (C4.FAPi), FAPi-46 and FAP2286 have been explored in this prospective study for their theranostic efficacy.

Materials and Methods: Twenty patients with various malignancies (8 HCC; 3 breast ca; 1 ovary ca; 2 GB ca; 3 ACC; 3 NSCLC) were enrolled and randomly divided into four groups. Each group underwent both FDG and FAPi PET (SA.FAPi, 5m.FAPi, C4.FAPi, FAPi46) on separate days. For biodistribution, SUVmax and SUVmean values were computed. For comparison with FDG, both visual (5-point Deauville score) and semi-quantitative analysis was performed. Lesion tracer uptake was quantified using SULpeak, SULavg, TBR, TLG for FDG and total lesion FAP expression (TLF) for 68Ga-FAPi. A low-dose dosimetry was performed for three 177Lu-FAPi (20mCi) derivatives (SA.FAPi, FAPi46, FAP2286) in 3 ACC patients using OLINDA/EXM® V2.0.

Results: Comparable biodistribution patterns were noted for SA.FAPi, 5m.FAPi, and C4.FAPi, with uptake in salivary glands, thyroid, liver, pancreas, and muscles, unlike FAPi46, which demonstrated uptake in salivary glands and muscles with lowest background uptake. In disease identification, all FAPi derivatives had Deauville score 4 (vs FDG 4). Overall, 100% concordant scan findings were noted in all patients for all FAPi derivatives and FDG. In sub-categorical analysis, higher Ga-FAPi avidity was noted in lesions compared to FDG for three FAPi molecules (SA.FAPi SULpeak vs FDG SULpeak: 7.0 ± 3.6 vs 5.0 ± 2.8; 5m.FAPi SULpeak: 5.1 ± 3.8 vs 3.4 ± 2.0; C4.FAPi SULpeak: 8.7 ± 5.2 vs 5.4 ± 3.2) in contrast to FAPi46 where lower mean SULavg (8.2 ± 7.4 vs 8.8 ± 6.0 for FDG). Lesion TLF values were higher than TLG values for SA.FAPi and C4.FAPi in contrast to FAPi46 and 5m.FAPi which demonstrated lower TLF values. Mean TBR for three FAPi molecules were comparable to FDG (2.5 ± 1.1 vs 2.6 ± 1.1) except FAPi46 which showed high mean TBR (8.4 vs 12.5 vs 6.7 ± 5.7). In dosimetry study, 177Lu-FAPi46 and SA.FAPi demonstrated favorable biodistribution however, maximum washout of both radiotracers from lesion was observed at 24 h with only 0.2% of I.D retained in lesion after 48 h. 177Lu-FAP2286 demonstrated favorable biodistribution and prolonged tumor retention time (>10 days post-therapy) with an absorbed dose estimate of 2.1 ± 0.2 mGy/MBq.

Conclusions and References: All FAPi derivatives proved to be effective diagnostic probes however, FAPi46 may offer additional advantages in detecting pancreatic malignancies. FAP2286 emerged as a choice of molecule for therapeutic applications.

Abstract ID: 43: Efficiency of 131-iodine- high dose therapy in papillary thyroid carcinoma

S. Nivetha, E. Venkatachalapathy, M. Palani, K. Sibu, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Papillary thyroid carcinoma (PTC) is the most prevalent form of thyroid cancer, accounting for approximately 80% of all thyroid malignancies. Standard treatment involves thyroidectomy followed by radioactive iodine (¹³¹-iodine) therapy. The role of high-dose ¹³¹-iodine therapy in improving outcomes in PTC patients remains a subject of ongoing research and debate.

Materials and Methods: This retrospective study involved 15 patients diagnosed with papillary thyroid carcinoma who underwent total thyroidectomy followed by high-dose ¹³¹-iodine therapy. The study analysed the clinical outcomes of ¹³¹-iodine therapy by assessing recurrence rates and survival over a 6-month follow-up period. Data were collected over a period of 1 year, and statistical analysis was performed to compare outcomes.

Results: Among the 15 patients, 85% showed significant improvement in disease control. The overall recurrence rate was 10%, primarily in high-risk patients with advanced-stage tumours. The 1-year survival rate in patients treated with RAI was 95%, with the highest success observed in early-stage papillary thyroid carcinoma. Side effects of iodine therapy were generally mild, with only 5% of patients experiencing moderate-to-severe adverse reactions. The data indicate that iodine therapy effectively reduces recurrence rates, especially in low-to-intermediate-risk patients.

Conclusions and References: High-dose ¹³¹-iodine therapy proves to be an effective approach for improving disease-free survival and reducing recurrence rates in patients with papillary thyroid carcinoma, especially in those with high-risk features. This treatment modality offers substantial clinical benefits with manageable side effects, making it a valuable component of PTC management.

Abstract ID: 54: Role of combined stimulated thyroglobulin and antithyroglobulin in predicting efficacy and prognosis of I-131 therapy in well differentiated thyroid carcinoma patients post thyroidectomy

Hemanth Penagadam, Tekchand Kalawat, R. Ramya Priya

Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India

Introduction: Thyroglobulin (Tg), most widely used biomarker for follow-up of differentiated thyroid carcinoma (DTC) patients after thyroidectomy, that helps in the diagnosis of residue, recurrence and progression. Presence of Antithyroglobulin antibodies (Anti-Tg) indicates autoimmune thyroid disease and complicate interpretation of Tg levels. Evaluating both Stimulated Tg (sTg) and Anti-Tg helps clinicians to improves the ability to predict outcomes more accurately.

Materials and Methods: We retrospectively studied 294 DTC patients with positive diagnostic I-131 whole body scintigraphy and received I-131 therapy from January/2018 to December/2023. Patients were divided into four groups based on sTg and Anti-Tg levels. Group A (Normal sTg and Anti-Tg), Group B (Elevated sTg and Normal Anti-Tg), Group C (Normal sTg and Elevated Anti-Tg), Group D (Elevated sTg and Anti-Tg). We compared these groups based on age, gender, histological types, tumour stage, risk stratification size, and I-131 dose using independent Chi square and Z-tests. Receiver operating characteristic (ROC) curve analysis was performed to obtain optimal cut-offs values for pretherapy sTg, Anti-Tg, sTg × Anti Tg product.

Results: Out of 294 DTC patients 206/294 (70%) were females, 88/294 (30%) were males with mean age 55.8+15.3 years. In each group, Iodine-131 dose, pretherapy sTg, Anti-Tg, sTg×Anti Tg product shows statistically significant difference between groups (p<0.05). Age, gender, pathological type, TSH level doesn’t show any statistically significant differences between the two groups (p>0.05). During first follow up, Group A and B patients shows complete structural and biochemical response with no further I-131 therapy, whereas Group C and D shows partial response (30%), stable disease (35%), progression (25%), Thyroglobulin elevated negative iodine scan (TENIS) (10%) status with altered biochemical profile and received further I-131 therapy. ROC analysis shows optimal cut off of 2.89, 18.2 and 22.72 for pretherapy sTg, Anti Tg, sTg×Anti Tg respectively.

Conclusions and References: The current study highlights that in presence of high Anti-Tg antibodies, patient may get incomplete clearance of Tg producing thyroid cancer cells after I-131 therapy and patient may develop refractory state requiring multiple sessions of I-131 therapy and may eventually labelled as TENIS. sTg x Anti-Tg product helps in predicting the response to I-131 therapy in DTC patients and patients with partial response may be considered for alternative lines of therapy.

Abstract ID: 56: Response assessment of 3700 MBq radio iodine ablation in papillary thyroid cancer patients with scintigraphic evidence of nodal or distant metastases

Adersh Stanly, Julie Hephzibah, Saumya Sunny, Justin Benjamin, David Mathew, Junita John, Paul Jacob

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Papillary thyroid carcinoma (PTC) with nodal/distant metastases has a higher incidence of disease persistence and recurrence. Post thyroidectomy, American Thyroid Association (ATA) guidelines (2015) suggests dose of 3700 MBq for residual thyroid and 5550 MBq to >7400 MBq for those with metastases. Our Institutional policy suggests 3700 MBq RAIA to patients with metastases and repeat doses of 3700 MBq at each visit if required. This study was done to assess treatment outcome in our patients in comparison with those who received higher doses of RAIA, as per ATA guidelines.

Aim: To assess the efficacy of doses of 3700 MBq RAIA in PTC patients with scintigraphic evidence of nodal or distant metastases.

Materials and Methods: Retrospective analysis of PTC patients treated with RAIA (3700 MBq) over 10 years with scintigraphic evidence of nodal or distant metastases with minimum follow up of 2 years was done. Histopathological and treatment details, scintigraphic scans and serum thyroglobulin were recorded. Treatment outcomes were categorised based on ATA response criteria.

Results: Among 1926 patients treated with RAIA, 306 patients (118 M/ 188 F, >55 years: 47/ < 55 years: 259, mean: 57 yrs, range: 18-75 years, follow-up range: 2 - 12 years, mean: 5.6 years) fulfilled the criteria with scintigraphic evidence of nodal/distant metastases were included. Initial serum thyroglobulin ranged from 0.10 ng/dl to 189100.00 ng/dl (mean S.Tg 2470.50 ng/dl). Total cumulative dose of RAIA ranged from 1850 MBq-25,900 MBq (upto7 doses). Of 306 patients, 203 had local metastases and 103 had distant metastases. Overall, response was excellent in 50.3% indeterminate in 17.6%, biochemically incomplete in 13.4% and structurally incomplete in 18.6%. Among nodal metastases patients, response was excellent in 61.6%, indeterminate in 18.6%, biochemically incomplete in 13.3% and structurally incomplete in 6.9%. In distant metastases patients, response was excellent in 28.2%, indeterminate in 16.5%, biochemically incomplete in 13.6% and structurally incomplete in 41.7%.

Conclusions and References: The long-term efficacy was similar to those who received higher doses of RAIA. A dose of 3700 MBq RAIA is cost-effective, minimizes radiation exposure with an additional advantage of offering multiple doses on serial follow up when necessary.

Abstract ID: 74: Role of 131I high dose therapy in patients with differentiated thyroid carcinoma having distant metastasis

G. Sakthivelayudham, E. Venkatachalapathy, M. Palani, K. Sibu, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Iodine-131 High Dose Therapy (131I-HDT) is a therapeutic approach for treating Differentiated Thyroid Carcinoma (DTC). In advanced stages, DTC may cause metastasis through lymphatic spread to distant organs such as the lungs, lymph nodes, liver, bones, and brain. The mechanism by which 131I-NaI is localized in thyroid tissues, utilizing the Sodium Iodide Symporter, allows for the targeting and destruction of distant metastatic thyroid cells.

Materials and Methods: 131I-Whole Body Survey (131I-WBS): Post thyroidectomy patients with DTC undergo 131I-WBS approximately 30 days after surgery to detect remnant thyroid tissue. Patients are prepared by halting thyroid hormone supplements and limiting iodine intake for 3-4 weeks. After oral administration of 131I-NaI, gamma camera scans are performed to identify remaining thyroid tissue or metastasis. 131I-HDT: Patients with remnant thyroid tissue and metastasis in organs such as lymph nodes, lungs, and bones receive 131I-NaI therapy, with doses ranging from 5.55GBq (150 mCi) to 7.4 GBq (200 mCi), depending on the severity. Patients are isolated and discharged once radiation exposure drops to safe levels (5 mSv). Post-therapy scans are conducted 144 hours after treatment to assess 131I localization in thyroid and metastatic tissues. Follow up scan: Six months after 131I-HDT, another 131I-WBS is performed. If metastatic tissue is still detected, subsequent treatment doses are determined, and the process is repeated. Absence of scintigraphic evidence is confirmed via serum thyroglobulin levels.

Results: Of the 21 patients evaluated, 15 had lymph node metastasis, which was fully resolved after a single round of 131I-HDT. Serum thyroglobulin levels correlated with these results. In contrast, patients with lung (3) and bone (3) metastasis exhibited persistent metastatic activity after the first round, but a significant reduction in activity was observed after the second round of treatment.

Conclusions and References: 131I-HDT is highly effective in resolving lymph node metastasis in DTC patients after a single treatment round. For lung and bone metastasis, multiple treatment rounds significantly reduce metastatic activity. This highlights the role of 131I-HDT in managing advanced DTC.

Abstract ID: 87: Radioiodine therapy for differentiated thyroid cancer in children

Tamara Geliashvili, A. A. Lee, M. O. Goncharov, O. D. Baranova, A. V. Parnas, V. S. Ilyakov

Federal State Budgetary Institution (N.N. Blokhin National Medical Research Center of Oncology) оf the Ministry of Health of the Russian Federation (N.N. Blokhin NMRCO), Moscow, Russia

Introduction: Children are not “miniature” adults! Most experts around the world recognize the differences between adult and pediatric thyroid cancer (TC) and emphasize the need for specific guidelines for the pediatric population. In comparing the two guidelines (ATA 2015 and ETA 2022) with each other and with Russian clinical guidelines for the treatment of childhood TC, we found significant differences in determining the tactics of treatment and examination during radioiodine therapy (RIT). The aim of report is to analyze our experience with RIT in children with DTC and to identify the most unresolved issues in the context of current international and Russian recommendations.

Materials and Methods: From December 2021 to April 2024, 130 pediatric patients (median age 14 years (6-18), 98 girls and 32 boys) underwent 141 RIT courses at the N.N. Blokhin National Medical Research Center of Oncology (Russia). All patients underwent surgical treatment of a primary or recurrent tumor.

Results: According to postoperative histological examination, 109 (84%) patients were diagnosed with classic papillary cancer (PC), 21 (16%) patients had aggressive subtypes of PC. The evaluation of the primary tumor process extent revealed: multifocality in 63 (48%) patients, involvement of neck lymph nodes in 115 (88%), lung metastases in 14 (11%). Adjuvant RIT to ablate residual thyroid tissue and reduce the risk of recurrence were performed at an average 131I activity of 2 GBq (1, 1-4 GBq), therapy of lung metastases with 131I 4 GBq (1,83-5 GBq). Out of 14 patients with lung metastases, 3 patients had radioiodine refractory process. Lung metastases were associated with an advanced primary process (T3-4, N1b) and high TTG-stimulated thyroglobulin levels (from 118 ng/ml to >5,000 ng/ml).

Conclusions and References: On the way to a personalized treatment strategy for children with DTC prospective multicenter studies and the creation of international registries are needed.

Abstract ID: 110: Process experiences of the state of art production facility for the indigenous preparation of I-131 oral radio-pharmaceutical products using 131I produced from 235U fission

Prabhakar Ganti, C. Senthil Kumar, Tejaswini Kala, R. N. V. S. Jagadeesh, G. Sainadh, Ravi Seshan, N. Siva Prasad, Ganti Eswar

Ganti Radioisotope Laboratories, Vijayawada, Andhra Pradesh, India

Introduction: “Ganti Radio Isotope Laboratories [GRIL]” set up a state-of-the-art manufacturing facility, in private enterprise, for the formulation of I-131 radiopharmaceutical products & supply to all existing centers in our country on “As & When Required Basis”. The I-131 oral formulations available on weekly basis, comprise “I-131 NaI solution doses, 25-800 mCi and I-131 NaI Capsules, 3-50 mCi doses. This facility is functional with the commercial runs started in September 2023 and presently reaching to around 100 hospitals and institutes in India.

Materials and Methods: Facility’s five hot cells are indigenously designed, fabricated and confirm to all stipulated radiation safety features by AERB along with the operator friendly safety features in addition to the clearance from all local regulatory bodies. We are licensed by AERB, to manufacture and supply these RPh. Products with bulk handling of 70 Ci of I-131 twice a week. Strict adherence to SOP for formulation of “I-131 NaI solution doses and I-131 NaI Capsules doses.

Results: Since its inception i.e. Sep.2023, till now more than fifty batches were processed successfully using 131I activity in the range of 185–740 GBq for formulation of 131I solution /capsules doses, in-house QC/QA for evaluation to the final packaging of the prepared doses and supplying them to various user hospitals. These products comply with IP/USP pharmacopeia specifications.

Conclusions and References: Excellent clinical response on our products and good quality images are reported by the user clinicians. Plans are in progress to start Lu-177 RPh. Products in this facility from Jan.2025.

Abstract ID: 128: 68Ga-DOTATATE PET/CT – A potential game changer for suspected dedifferentiated thyroid carcinoma incidentally detected with 99mTc-RGD scan

G. Harinee, Kabilash Dhayalan, Vasanth Madivanane, Ragire Sainath, Harish Goyal, Dhanapathi Halanaik, Nandini Pandit

JIPMER, Puducherry, India

Introduction: Papillary thyroid carcinoma has a favorable prognosis following surgery +/-radioiodine treatment. However, the existence of dedifferentiation, which eventually causes radioactive iodine refractory (RAIR) thyroid carcinoma, presents a challenge to the treating physicians. Thus, a newer tracer is required to deal with both diagnostic and therapeutic challenges. 99mTc-labeled RGD (arginine-glycine-aspartate) imaging is found to be a promising marker of tumor angiogenesis which targets αVβ3 receptors and useful to assess patients with RAIR thyroid cancer. 68Ga-labeling of DOTA chelator-conjugated somatostatin analogs allows to detect and bind with tumors expressing selected somatostatin receptors. Several reports of these markers have been published in world literature, however no literature has compared the concordance/discordance of RGD with DOTA. Here, we report a 54-year-old female diagnosed with papillary thyroid carcinoma, showing concordant findings in both 99mTc-RGD & 68Ga-DOTA scans guiding a way for PRRT treatment.

Materials and Methods: The patient was diagnosed with Papillary thyroid carcinoma and underwent total thyroidectomy. Post-operative histopathological examination showed papillary thyroid carcinoma, extensive angioinvasion & lymphovascular invasion with Tg-2110 ng/mL, Atg-4.8 IU/mL and categorized as ATA high risk. 131I-Diagnostic whole body scan (WBS) revealed 131I-avid remnant in the thyroid bed. She was treated with two cycles of radioactive-iodine ablation, six months apart. Follow-up Tg-1324 ng/mL and WBS revealed mild tracer avid skull metastases. 99mTc-RGD scintigraphy was done, which revealed intense tracer avid skull metastasis at the same site, which in correlation with CT showed expansile lytic lesion. In view of suspected dedifferentiation, 68Ga-DOTATATE PET/CT was done.

Results: 68Ga-DOTATATE PET/CT revealed SSTR-expressing predominantly lytic multiple skeletal lesions, low grade SSTR-avid multiple subcentimeteric nodules in bilateral lung fields and ill-defined residual thyroid tissue. The patient was then treated with 2 cycles of PRRT therapy with 88 mCi & 140 mCi of 177Lu-DOTATATE at an interval of 8 weeks. (Response assessment 68Ga-DOTATATE scan is yet to be done).

Conclusions and References: In our attempt to add further knowledge to the literature, this case emphasizes the concordance in the findings of skull metastasis in 99mTc-RGD and 68Ga-DOTATATE scans thus paving a way for 177Lu-PRRT therapy and therapy potential with 177Lu labeled RGD peptides. Further we need to establish the comparison of 68Ga-RGD PET/CT and 68Ga-DOTATATE PET/CT scans in the future to pave the way for new targeted therapies using radionuclide with both peptide receptors.

Abstract ID: 163: Study to investigate the discharge criteria for patients undergoing 30mCi radioiodine therapy

Sreeraj Kannan, K. K. Kamaleshwaran, E. Ramkumar, R. Radhakrishnan, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: Aim of this study is to measure the radiation exposure patients undergoing 30 mCi radioiodine therapy. Iodine-131 (I-131) is widely used for radioiodine therapy, particularly in the treatment of thyroid cancer. Patients with low risk thyroid cancer was treated with 30 mCi of I-131 sodium iodide (NaI). The discharge criteria approved by the Atomic Energy Regulatory Board (AERB) patients stipulate a maximum radiation exposure of 5 mR/h. The aim of this study is to investigate the actual radiation exposure from patients during low dose therapy [30 mci] to determine safe discharge criteria.

Materials and Methods: After the administration of Iodine-131 NaI, patients were asked to sit in the waiting area for a specified duration. Radiation exposure was measured at 0-, 1-, 2-, and 3 hours post-administration using a survey meter at a distance of 1 meter from the patient and determine the appropriate time for patient discharge.

Results: Radiation exposure measurements taken at immediate time of administration is 4mR/hr and 1-hour post-administration averaged value of 2.7mR/hr and 2 hour post-administration averaged 2.3mR/hr, 3 hour post-administration averaged 2mR/hr.

Conclusions and Reference: Patients undergoing 30 mCi I-131 therapy exposure rate showed 4 mR/hr immediately after administration, so that we can discharge the patients immediately after the administration. The patients are no need to wait after administration. But if we wait for 2 hours and send the patient, radiation exposure to the public will decrease by 50%.

Abstract ID: 197: Predicting 24-hour RAIU value using 99m Tc-pertechnetate thyroid uptake scan in patients with Graves’ disease: A prospective study

Sharungbam Bidyapati Devi

PGIMER, Chandigarh, India

Introduction: Graves’ disease (GD) is the most common cause of hyperthyroidism. Radioactive iodine (RAI) therapy is preferred in patients with worsening of GD and in the patients who have been treated with antithyroid drugs for longer duration without achieving cure. For RAI therapy to be effective in treating GD, the administered activity must be calculated appropriately in order to maximize therapeutic benefit. Currently, this calculation is done using 24-hour RAI uptake (RAIU) value. In this study, we explored the potential role of 99m Tc-pertechnetate (99m TcO 4-) thyroid scan and its uptake value in predicting the 24-hour RAIU value.

Materials and Methods: 40 patients (age ≥18 years) diagnosed with Graves’ disease who were refractory to antithyroid drugs and never received RAI ablation were included in this prospective single-center study. All the patients underwent thyroid scan 20 minutes following the IV administration of 4 mCi of 99m TcO 4 -, and 24-hour RAIU study following oral administration of 5 µCi of 131- I. Correlation and regression analyses were undertaken between the 99m TcO 4 - thyroid scan uptake value and the 24-hour RAIU value.

Results: The mean 99m TcO 4 - thyroid uptake value was 12±9% while the mean 24-hour RAIU value was recorded to be 63±15%. A statistically significant moderate positive correlation was observed between the two values (Pearson correlation coefficient, r = 0.421, P = 0.007). Using the 99m TcO 4 - thyroid uptake value as the independent variable and 24-hour RAIU as the dependent variable, linear regression analysis provided the regression equation as: 24-hour RAIU = 0.717*(99m TcO 4 - thyroid uptake value) + 54.192 (r 2 = 0.178, P = 0.007). The mean predicted 24-hour RAIU value using 99m TcO 4 - uptake value in the above equation was 63±6%. No statistically significant difference was observed between the actual and predicted 24-hour RAIU values (P = 0.993).

Conclusions and References: 99m TcO 4- thyroid scan and uptake value was seen to be significantly associated with the 24-hour RAIU value and may be explored as a surrogate marker for the same. Further studies are required to validate this equation for predicting 24-hour RAIU using 99m TcO 4 – uptake value.

Abstract ID: 207: Clinical outcomes of radioactive iodine (I-131) therapy in paediatric differentiated thyroid carcinoma patients: A single centre retrospective study

Paladugula Lakshmi Pratyusha, N. Ajit, C. B. Virupakshappa, B. Prathyusha, A. Zakir Ali

Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India

Introduction: Thyroid cancer is the most prevalent endocrine malignancy in adults. However, it is less common in the paediatric population, representing less than 2% of all differentiated thyroid cancer (DTC) cases. Paediatric patients with DTC are often diagnosed at a more advanced disease stage, with more than 50% presenting with lymph node metastases at the time of diagnosis. Despite the advanced disease stage at the time of diagnosis, paediatric DTC patients generally exhibit a favourable response to treatment. The current study aims to assess the incidence of advanced disease and treatment outcomes of paediatric DTC patients at our institution.

Materials and Methods: We have reviewed the medical records of paediatric DTC patients who received Radioactive iodine therapy in our institute from March 2009 to October 2022.

Results: A total of 96 patients (64 females and 32 males) with mean age of 15+2.6 years (Range: 6-18 years) were included in the study. 80/96 (83.3%) patients had papillary carcinoma and 16/96 (16.7%) had follicular carcinoma thyroid. 24/96 (25%) patients had no metastases. 71/96 (73.9%) patients had lymph node metastases. 16/96 (16.7%) of the patients had distant metastases (Lung metastases-16/96, liver metastases-1/96, skeletal metastases-2/96). Empirical I-131 dose similar to the adult population was administered to the patients. Low risk patients were treated with dose of 30-100 mCi, intermediate risk patients were treated with 100-150 mCi and high risk/distant metastases patients with 150-200 mCi. The mean duration of follow-up was 106.5 months (range-24-180 months). Out of 24 patients with low-risk DTC, complete response was achieved with a single dose in 20/24 (83.3%), and with a second dose in 3/24 patients. One of them had a biochemically incomplete response. In the intermediate risk group complete response was seen in 42/55 (76.3%) patients with a single dose, 4/55 (7.2%) patients required a second dose. 9/55 (16.3%) patients had indeterminate response/ progression. 5/55(9.1%) patients had lymph nodal recurrence and were treated accordingly. Of the 16 patients with distant metastases, the disease was stable on follow-up for 13/16 patients and 3/16 patients had progressive disease. No long-term side effects were seen in our patients. No mortality was noted.

Conclusions and References: Paediatric thyroid carcinoma is a relatively uncommon clinical entity. A limited number of studies have been conducted to validate the appropriate radioiodine therapy dosage following surgical intervention in the paediatric patient population. Our study findings suggest that the outcomes of empiric I-131 therapy administered after surgery in the paediatric cohort is comparable to the adult population with no substantial long-term adverse effects and reduced recurrence rates.

Abstract ID: 37: Multi-Curie 177Lu-PSMA clinical dose formulation using semi-automated production system for prostate cancer therapy

Navin V. Sakhare^1,2, N. C. Joseph¹, B. K. Tiwary¹, Arpit Mitra¹, Pooja Kale¹, Chetan Kothalkar¹, K. S. Ajish Kumar³, Anupam Mathur^1,2, Sudipta Chakraborty³, Usha Pandey¹, V. V. Murhekar¹

¹Radiopharmaceuticals Program, Board of Radiation and Isotope Technology, Navi Mumbai, Maharshtra, ²Department of Chemistry, Mangalore University, Mangalore, Karnataka, India, ³BRIT and Mangalore University, India

Introduction: 177Lu-PSMA-617 is a proven therapeutic radiopharmaceutical used for the treatment of prostate cancer. Many of the radiopharmacies world over synthesize this radiopharmaceutical using compact automated/semi-automated modules. However, commercial module design capacity limits the number of patient doses that can be synthesized in a single batch. Till date up to 0.7 Ci activity has been utilized for the synthesis of patient dose formulation using commercial modules. The present work describes a synthesis set-up that has been successfully deployed for the radiochemical synthesis of 177Lu-PSMA-617 utilizing 7.5 Ci 177Lu activity in a single batch.

Materials and Methods: PSMA-617.TFA was purchased from MedKoo Biosciences, USA. 177LuCl3 with specific activity (15-20 Ci/mg) was produced in the DHRUVA reactor, BARC. Radiochemical synthesis of 177Lu-PSMA-617 was carried inside 50 mm lead shielded glove-box plant equipped with a dry heat bath for holding a reaction vial up to 50 mL capacity. Calculated amount of peptide (4.5 mg) dissolved in 0.1 M acetate buffer (pH 5) was loaded inside the plant and 177Lu activity (7.5 Ci) was remotely added to the reaction mixture and heated at 90 □C for 45 min. After the completion of reaction, few microliters of sample were remotely withdrawn for QC analyses. On observing the radiochemical purity (RCP) > 95%, the reaction mixture is suitably diluted (~22 mCi/mL) using 0.1 M acetate buffer containing sodium ascorbate (2%). If the RCP < 95%, the product is purified using C18 cartridge under positive nitrogen pressure and pure product is eluted out in 50% ethanolic solution. The diluted product was then dispensed using an auto dispenser as unit patient dose (200 mCi) via peristaltic pump fitted with 0.22 □m syringe filter in a capped vial (15 mL).

Results: More than 10 production batches of 177Lu-PSMA-617 (~7.5 Ci per batch) was carried out successfully using semi-automated synthesis system. The total production time for each batch varied between 3-4 h and the specific activity of the labeled product achieved was >1 mCi/nmol of the peptide. The ready to use formulation was found suitable for patient use up to a period of 3 days from the date of preparation (RCP >95%).

Conclusions and References: The results demonstrate successful 177Lu-PSMA synthesis of multi-patient dose formulation (30 patient doses) in a single batch utilizing 7.5 Ci 177Lu activity towards effective clinical use.

Abstract ID: 152: Optimizing outcomes in metastatic castration-resistant prostate cancer: Unveiling key predictors of response to Lutetium-177 PSMA therapy

Bhanu Jain, Dinesh Srivastav, Aftab Hasan Nazar, Sanjay Gambhir

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: The goal of this study is to identify predictors of outcomes following ¹⁷⁷Lu-PSMA therapy.

Materials and Methods: 55 patients with metastatic castration-resistant prostate cancer (mCRPC) who were treated between September 2020 and December 2023 and were eligible for Lu-177 PSMA therapy were included in this retrospective cohort analysis. Twenty-nine pretherapeutic clinicopathological variables—including time since diagnosis, initial risk, treatment history, baseline lab values (S.ALP, S.LDH, Hb, TLC, platelets, S.creatinine, GFR, PSA) and [68Ga]-PSMA-11 PET/CT variables—were among the predictive factors analyzed. These included bone and soft tissue metastases, number of metastases, pelvic/distant nodal involvement, and superscan appearance. Local data collection methods were employed, and patients were monitored for a duration of 12 months. The study’s main objectives were survival overall and survival free of PSA advancement.

Results: Out of 55 individuals, 96.36% received an adenocarcinoma diagnosis, while 3.63% had an intraepithelial neoplasia of the prostate. Seven patients had a Gleason score of less than seven, while 46 patients had a score of seven or higher, with a median overall survival of twenty-six months. 33 patients had orchidectomies, with a median survival of 23 months as opposed to 31 months for the 22 patients who did not have the surgery. Of the 55 patients, 25 had chemotherapy (median overall survival of 27 months), while the remaining 30 did not receive chemotherapy (median overall survival of 27 months). PSA baseline mean was 199.32 ng/mL (SD = 411.25), decreasing to 92.69 ng/mL (SD = 178.57) after the first therapy, but rising to 171.68 ng/mL (SD = 374.05) after the last session. Notably, patients with PSA levels ≤56.01 ng/mL had a median survival of 38 months, compared to 25 months for those with levels ≥56.02 ng/mL.

Conclusions and References: This study highlights the importance of PSA levels as a prognostic factor, while interventions like orchidectomy and chemotherapy did not demonstrate a significant difference in survival outcomes. Gleason scores >7 and high PSA levels appear to be associated with worse prognosis in this patient cohort.

Abstract ID: 187: Impact of Lu-177 PSMA-617 therapy on mGFR in metastatic castration-resistant prostate cancer patients

Srishti Srivastava, Rajvir, Aftab H. Nazar, Manish Ora, Sanjay Gambhir

Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Prostate cancer is among the most prevalent cancers in men worldwide, with rising incidence rates observed in India. For patients facing disease progression or resistance to conventional therapies such as androgen deprivation, chemotherapy, and radiotherapy, Lu-177 PSMA-617 therapy has emerged as a promising alternative. Given that the kidneys serve as the main excretory organ for the radiopharmaceutical, there are serious concerns about the treatment’s renal safety. The purpose of this study is to assess how Lu-177 PSMA-617 therapy affects patients with metastatic castration-resistant prostate cancer (mCRPC) in terms of their measured glomerular filtration rate (mGFR).

Materials and Methods: We conducted a retrospective analysis of 26 mCRPC patients treated with 5.5-7.4 GBq of Lu-177 PSMA-617 for up to 4-6 cycles. Comprehensive medical and demographic data were collected, including age, medical history, and prior chemotherapy or radiotherapy. Baseline mGFR was measured using the plasma clearance method with the tracer 99mTc-DTPA. We compared the baseline mGFR to the post-therapy mGFR assessed after the third cycle, approximately six weeks post-therapy. SPSS software was used for statistical analysis.

Results: Out of 26 patients of mCRPC, the mean age was 70.80 years (52-84 SD= 8.1), 15 (57.6%) patients had received prior chemotherapy and 15(57.6) had pre-existing comorbidities including diabetes, hypertension and hypothyroidism, out of which 10 (38%) patients had been heavily treated with chemotherapy and also had pre-existing comorbidities. Mean baseline mGFR was 51 ml/min/1.73 m2 BSA (30-81, SD=14.9). The mean mGFR post 3 cycles of Lu-177 PSMA-617 therapy was 45 ml/min/1.73 m2 BSA. (28-72, SD=11). The difference in pre-treatment & post treatment mGFR was found to be significant (p value: 0.02). The average change in mGFR noted was 18%. Notably 7/26(26%) patients had an increase in mGFR with 3/26(11%) having more than 30% increase in GFR. Conversely, 18/26(69%) had a mild decrease in mGFR. None of the patients developed Grade 3 or greater CKD and none required dialysis despite multiple comorbidities, advanced age and prior chemotherapy.

Conclusions and References: In this retrospective study of 26 patients with mCRPC undergoing Lu-177 PSMA-617 therapy, we observed that the majority of patients had stable renal function, and only a small percentage exhibited significant changes in mGFR. The mean baseline mGFR was 51 mL/min, decreasing slightly to 45 mL/min post-therapy, which did not reach the threshold for clinical significance in most cases. These findings suggest that Lu-177 PSMA-617 therapy may be well-tolerated in terms of renal function, even in a cohort with advanced age and multiple comorbidities. Further prospective studies with larger sample sizes are warranted to confirm these results and better understand the long-term renal implications of this therapy.

Abstract ID: 188: Hematological adverse effects associated with 177Lu- PSMA radioligand therapy: A retrospective study in metastatic castration resistant prostate cancer patient

Ashcharya Gupta, Aftab Hasan Nazar, Sanjay Gambhir, Prasanta Kumar Pradhan

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: This study looks into the hematological adverse effects of 177 Lu- PSMA RLT after completion of 4 or more cycle of RLT therapy and comparison of hematological parameter between baseline and post therapy values (21 days after post therapy).

Materials and Methods: In this study, a retrospective analysis was conducted on patients who were diagnosed with metastatic castration resistant prostate cancer (mCRPC) and received 4 or more cycle of 177 Lu RLT treatment between 2020 to 2024. The hematological outcomes of RLT was performed using pre and post treatment comparative analysis using paired t test. Results were compared according to CTCAE version 5.

Results: Hemoglobin analysis- At baseline, there were no anemia in 8 patients, there were grade I anemia in 6 patients, there were grade II anemia in 3 patients. At completion, there were no anemia in 2 patients, there were Grade I anemia in 6 patient and there were Grade II anemia in 9 patients. On comparative analysis, 8/17 (47%) there was no change in grade, 3/17 (17.6%) from no anemia to Grade I, 3/17 from no anemia to Grade II, 3/17 from Grade I to Grade II. Platelet analysis- At baseline, there were no thrombocytopenia in 15 patients and there were 2 patients in which Grade I thrombocytopenia developed. At completion, there were no thrombocytopenia in 12 patients, there were Grade I in 3 patients and there were Grade II in 2 patients. On comparative analysis, 13/ 17 (76%) there were no change in grade, 2/17 (11.7%) from no thrombocytopenia to Grade I, 1/17 from no thrombocytopenia to Grade II, 1/17 from Grade I to Grade II. Neutrophil analysis- No neutropenia in all patients (17/17) before and after RLT.

Conclusions and References: This retrospective study provides valuable insights into the hematological adverse effects associated with 177Lu-PSMA radioligand therapy in patients with metastatic castration-resistant prostate cancer (mCRPC). The findings indicate that while a majority of patients experienced minimal changes in hematological parameters, with significant proportions maintaining stable hemoglobin levels and thrombocyte counts, some did experience varying degrees of anemia and thrombocytopenia. Notably, neutropenia was absent across all patients, highlighting a potentially favorable safety profile for this treatment modality. These results emphasize the importance of ongoing monitoring of hematological parameters during and after RLT, as changes in hemoglobin and platelet counts can influence patient management and treatment outcomes.

Abstract ID: 25: 177Lu-DOTATATE loaded nanofiber for treatment of neuroendocrine tumor after resection

Ravi Kumar Chauhan^1,2, Arvind Suresh^1,2, Priya Singh³, Santosh K. Gupta^1,2, Sanjeev K. Mahto³

¹Mahamana Pt. Madan Mohan Malviya Cancer Centre, BHU and Homi Bhabha Cancer Hospital (A Unit of TMC), ³School of Biomedical Engineering, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh, ²Homi Bhabha National Institute, Mumbai, Maharashtra, India

Introduction: Worldwide, cancer is one of the major causes of mortality. The current treatment -approaches available for therapeutic intervention of disease include chemotherapy, radiotherapy, and surgery. Considering the drawbacks of these therapies which includes the possibility of recurrence, it therefore is imperative to develop contemporary methods that offer controlled release of these drugs post-surgery to prevent the recurrence of cancer cells. In the present study, we have developed a novel method to incorporate a radioactive drug onto nanofibers and then place these fibers in the area of tumor resection. This approach aims to ensure that residual cancer cells may die, significantly reducing the chances of recurrence. To check the release and retention capacity of radioactive 177Lu-DOTATATE loaded nanofiber.

Materials and Methods: We fabricated biocompatible soy protein isolate and silk fibroin nanofibers using an electrospinning technique. We treated one portion of the nanofibers with ethanol and the rest without for further use. Later, we incorporated 177Lu-DOTATATE into the nanofibers via the physical absorption method. We checked the radiopharmaceutical’s release and retention capacity by placing the nanofibers into a solution and monitoring them regularly using a dose calibrator over 36 hours.

Results: It was found that the fiber treated with ethanol released approximately 71% of the 177Lu-DOTATAE within 2 hours in the medium. The nanofibers, not treated with ethanol, released only 53% of the drug. The possible reason could be that treatment with ethanol has promoted the crosslinking of nanofiber, thereby promoting the effective release of the drug.

Conclusions and References: It was determined that 177Lu-DOTATATE when incorporated into the nanofibers, presents a promising option for treatment following tumor resection since it helps in the controlled release of the drug. Animal studies will be evaluated in the next step of studies.

Abstract ID: 32: Challenges faced in 177lutetium dotatate therapy

Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Patients with neuroendocrine tumors (NETs) that are positive for the somatostatin receptor may benefit from lutetium-177 dotatate therapy. Despite its effectiveness, a number of obstacles stand in the way of this therapy’s broad use and ideal results. The main difficulties with lutetium dotatate therapy are discussed in this abstract, with particular attention paid to patient selection, treatment guidelines, and side effect control.

Materials and Methods: A comprehensive review was conducted, analyzing existing literature and clinical studies on lutetium dotatate therapy. Key databases such as PubMed, Scopus, and clinical trial registries were searched for studies published over the past decade. The challenges identified included criteria for patient selection, appropriate dosing regimens, radiopharmaceutical availability, and the management of therapy-related adverse events.

Results: The review emphasized a number of important difficulties: 1. Patient Selection: The best patient selection for therapy is complicated by variation in somatostatin receptor expression among NETs, which affects treatment response and prognosis. 2. Dosing Protocols: Inconsistencies exist in practice due to disagreements over the ideal number of treatment cycles and dosage schedule. 3. Radiopharmaceutical Availability: Implementing therapy is significantly hampered by the limited supply of lutetium-177 and the logistical problems associated with its production and distribution. 4. Adverse Effects: Patients frequently suffer from hematological toxicities, exhaustion, and nausea, among other side effects that might impair their quality of life and adherence to therapy.

Conclusions and References: Lutetium-177 dotatate therapy presents a valuable treatment option for neuroendocrine tumors, yet several challenges must be addressed to optimize its clinical application. Enhancements in patient selection criteria, standardization of dosing protocols, improved access to radiopharmaceuticals, and effective management of adverse effects are crucial for maximizing the benefits of this therapy. Future research should focus on refining these aspects to improve patient outcomes and broaden the therapeutic application of lutetium dotatate.

Abstract ID: 118: In-house preparation of 177Lu-DOTATATE using non-carrier added 177Lu for the treatment of neuroendocrine tumors

Ravi Kumar Chauhan, Arvind Suresh, Srikanth Saminathan, Jay Prakash Kumar, Manoj Kumar R. Chauhan, Uddeshya N. Jha, Ritwik Sinha, Ajay Kumar, Arvind Gupta, Bhola Kumar, Santosh Kumar Gupta

Mahamana Pandit Madanmohan Malviya Cancer Centre and Homi Bhabha Cancer Hospital (a TMC Unit), Homi Bhabha National Institute, Varanasi, Uttar Pradesh, India

Introduction: Radio-labelled somatostatin analogues, such as 177Lu-DOTATATE ([177Lu-DOTA0, Tyr3]-Octreotate) play an important role in peptide receptor-targeted radionuclide therapy (PRRT). PRRT with 177Lu-DOTATAE is the first Radiopharmaceuticals that has been approved in Europe, USA and Canada for the treatment of Neuroendocrine Tumors.

Materials and Methods: Non-career added 177LuCl3 was purchased from ITG (Germany). DOTATATE peptide along with Sodium Ascorbate, Ascorbic acid was purchased from B J madan & Co (New Delhi). Stock solution of buffer was prepared by mixing Sodium ascorbate (160 µg) and ascorbic acid (40 µg) in 15 ml of ultrapure water. PH of buffer should be in between 4-4.5. The peptide is provided as a 1 mg powder which is subsequently dissolved in 1 mL of ultrapure water and used in 100 µL aliquots.100 µl of DOTATATE peptide aliquots was added with 900 µl of buffer from stock solution was added in reaction vial. 200 mCi of n.c.a 177LuCl3 was added in reaction vial and reaction vial was heated in heated bath for 25 min at 90º. To ensure sterility, the final product is passed through a 0.22 µm Millipore filter. The product vial further diluted with 10 ml of 0.9% aq. NaCl before injecting to patients. Radiochemical purity (RCP) of final product was quantitatively analyzed by TLC Scanner as well as HPLC. Thin-layer chromatography-silica gel (TLC-SG) plates was used as a stationary phase and it was developed with a 0.1 M Tri-Sodium Citrate Dihydrate as a mobile phase.

Results: Quality of 20 batches of 177Lu-DOTATAE was evaluated. The average radiochemical purity as determined by ITLC was above 99% (n=17; 99.8 ± 0.05%) with Rf at 0.116 and the average radiochemical purity as determined by HPLC technique was above 97% (n=3; 97.3 ± 1.5%) for this period. pH of labelled 177Lu-DOTATAE product and waste (Unlabelled) were 6.8 and 4.5 for each batch respectively. The mean whole-body (chest dose) radiation dose recorded in Lu-177-DOTATATE labelling was 0.038 ± 0.004 mSv with mean duration 48.7 minutes.

Conclusions and References: The studies carried out suggest that therapeutic doses of 177Lu-DOTATATE could be prepared by using high specific activity, non-carrier added 177Lu for treatment of Neuroendocrine Tumors. Clinical studies demonstrated the uptake and retention of the tracer in Neuroendocrine Tumors.

Abstract ID: 184: Trial of neoadjuvant peptide receptor radionuclide therapy in paraganglioma: Our clinical experience

Ishi Gupta, H. Vignesh, Sai Kishore, Nandini Pandit, Harish Goyal, Dhanapathi Halanaik

Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India

Introduction: Trial of Neoadjuvant Peptide Receptor Radionuclide Therapy (PRRT) in Paraganglioma: our clinical experience. Peptide Receptor Radionuclide Therapy (PRRT) is a targeted radionuclide therapy applied in patients with well differentiated neuroendocrine tumors (NETs). The use of PRRT has been well established in the setting of treatment of metastatic NETs.

Materials and Methods: We report a case of a 37 year old female, who is a known case of hyperthyroidism on regular antithyroid medications, presented with a mass in the right lateral aspect of the neck associated with tremors and weight loss. During evaluation, a contrast enhanced computed tomography (CECT) scan revealed a heterogeneous intensely enhancing soft tissue dense lesion involving the right carotid sheath, highly suggestive of a carotid body tumor. Further a 24 hour urine metanephrine and normetanephrine levels were obtained- 35.99 micrograms (mcg) and 22125 mcg respectively. The lesion was deemed unresectable due to its proximity to major neovascular structures. PRRT was considered in this setting as a neoadjuvant modality to reduce the tumour size, facilitating resection. A baseline Ga-68 DOTATATE PET/CT was obtained, which demonstrated an SSTR avid right carotid sheath lesion highly concordant with paraganglioma. She underwent radio-iodine ablation with I-131 for hyperthyroidism (Grave’s disease). She received two cycles of Lu-PRRT (177Lu-DOTATATE - 80+164 mCi) 8 weeks apart. She underwent GFR estimation before every cycle of Lu-PRRT.

Results: Radiological (CECT) and Functional (Ga-68 DOTATATE PET/CT) response assessment scans were performed, which revealed stable disease. She further received 2 cycles of Lu-PRRT (100 mCi). 24 hour urine metanephrine (23.5 mcg) and normetanephrine (150.7 mcg) levels were assessed after 3 cycles of PRRT which showed significant improvement. Thus, the patient received a total of 4 cycles of Lu-PRRT averaging 109 mCi per cycle.

Conclusions and References: Our case demonstrates an upcoming area of application of PRRT. Although surgical resection was not possible in our case, symptomatic improvement was evident. Further studies towards dose escalation, frequency of administration, number of cycles to be administered and expected treatment outcomes are needed to further advance the utility of neoadjuvant PRRT.

Abstract ID: 221: Metastatic patterns of bronchial carcinoid tumors: A retrospective case series analysis

Parag Jilhare, Shivangi Dixit, Manish Ora, Prasanta Kumar Pradhan, Sanjay Gambhir

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Twelve individuals with lung carcinoid were the subjects of this retrospective observational case series, which was done to determine the general metastatic spread to different regional locations.

Materials and Methods: Twelve individuals with lung carcinoid were the subjects of this retrospective observational case series, which was done to determine the general metastatic trend to different regional locations. Every month, octreotide was administered to all patients. Six individuals had surgery, including debulking or lobectomies. DOTATATE treatment was also administered to six patients. Cisplatin and Etoposide were used as chemotherapy for one patient.

Results: Nine patients (75%) had lymph node metastases, while six patients (50%) had liver metastases in this analysis of 12 bronchial carcinoid cases. Furthermore, seven patients (58.3%) had bone metastases, while three patients (25%) had regional infiltration. Seven patients (58.3%) had sclerotic lesions and one patient (8.3%) had a lytic lesion among those with skeletal involvement. Skeletal metastases most frequently occurred in the spine, especially the thoracic spine, which was impacted in five patients (41.7%), with the pelvis and ribs following. These results highlight the substantial potential for bronchial carcinoid tumors to spread, with lymph node involvement being the most common.

Conclusions and References: This study demonstrates the substantial potential for bronchial carcinoid tumors to spread, with skeletal and lymph node metastases being especially common. The most prevalent site of dissemination was found to be lymph nodes, which were followed by skeletal metastases, with the thoracic spine being the most often impacted area. There was also significant liver metastases. Future diagnostic and treatment approaches may be guided by the distinct patterns in metastatic activity shown by the preponderance of sclerotic skeletal lesions over lytic ones.

Abstract ID: 12: Role of pre-processing before compressing nuclear medicine image using discrete cosine transformation: A phantom study

V. Puneeth Kumar, Anil Kumar Pandey, Jagrati Chaudhary, Chetan D. Patel, Rakesh Kumar

All India Institute of Medical Sciences, New Delhi, India

Introduction: Few studies have employed Discrete Cosine Transformation (DCT) for Nuclear Medicine (NM) image compression, however, the role of pre-processing these images before compression has not been explored. The value of sigma for Gaussian filter controls the level of smoothing. Excessive smoothing blurs the small details making these details indistinguishable from background. The value of threshold for discarding DCT coefficients determines the quality of compressed image. In this study, we explore the role pre-processing the image with Gaussian filter on the performance of image compression using Discrete Cosine Transformation; and optimize value of sigma and threshold in order to achieve highest compression ratio without compromising diagnostic information.

Materials and Methods: A phantom was constructed using patient tubing and a plastic box. With 88.8 MBq of Tc-99m pertechnetate injected into the tubing, dynamic studies of the phantom were conducted at various time intervals, and finally dynamic frames were summed to generate eight static images. The static image acquired at 0.3 hours was processed using Gaussian filters with sigma values of 1, 2, and 3, followed by applying DCT and thresholding the DCT coefficients at 0.1, 0.01, and 0.001. Inverse DCT was then used to produce compressed images. For each input image, nine compressed images were generated and compared with the original to select the one that achieved the highest compression ratio without compromising diagnostic information. The sigma and threshold values that produced the best result were considered optimized. The remaining seven images were compressed with optimized value of sigma and threshold. The compression ratio (CR) was calculated as the ratio of nonzero elements after thresholding the DCT coefficients to the number of nonzero elements before thresholding.

Results: The optimized values for sigma and threshold were determined to be 1 and 0.001, respectively. The average CR across eight input images was 1.685 (ranging from 1.24 to 2.52). However, after applying a Gaussian filter (sigma = 1) to the images before compression, the average CR increased to 5.807 (ranging from 4.54 to 7.25). Higher CRs were observed in images with lower pixel counts when pre-processed with the Gaussian filter.

Conclusions and References: Pre-processing images with a Gaussian filter enhance approximately four times the performance of image compression using Discrete Cosine Transformation (DCT).

Abstract ID: 13: Clinical applications of indigenously prepared 68Ga-NODAGA-RGD PET/CT over a spectrum of benign and malignant diseases

Priyanka Verma, Gaurav Malhotra, Ashok R. Chandak, Sandip Basu

Radiation Medicine Centre, Bhabha Atomic Research Centre, TMC Annexe, Mumbai, Maharashtra, India

Introduction: The tripeptide sequence of Arginine‐Glycine‐Aspartate (RGD) is the integrin binding domain, which is part of several extracellular matrix (ECM) proteins. Integrins are heterodimer, transmembrane glycoprotein cell adhesion molecules that are involved in cell‐cell and cell‐ECM interaction The RGD tripeptide sequence has high affinity and specificity towards the integrin αvβ3 which is over‐expressed on the tumor vasculature and is thus an excellent angiogenesis biomarker. As the tumor vasculature of several tumors express αvβ3 integrin, the angiogenic markers such as RGD peptide are useful for their imaging. Moreover, angiogenesis is considered an integral part of the repair process after ischemic injury and has been a major focus of cardiovascular and neurovascular research. Angiogenesis is considered an integral part of the repair process after ischemic injury and has been a major focus of cardiovascular and neurovascular research.

Aims: The aim of the study is to illustrate the clinical applications indigenously prepared 68Ga-NODAGA-RGD PET/CT over a spectrum of benign and malignant diseases.

Materials and Methods: This was a retrospective analysis of the 68Ga-NODAGA-RGD PET/CT scans done from 2021 to 2024. The scans were analyzed in relation to the indication for which they were performed.

Results: There were total 112 68Ga-NODAGA-RGD PET/CT scans done for various benign and malignant clinical indications. The indications for which the scans were performed included benign conditions like ischemic heart disease, vascular diseases while malignant conditions included sarcomas, adrenocortical carcinoma, paragangliomas, carcinoma breast and carcinoma thyroid.

Conclusions and References: Our analysis of the 68Ga-NODAGA-RGD PET tracer uptakes in a various benign and malignant conditions implies that 68Ga-NODAGA-RGD PET/ CT is an efficient imaging modality. It may be considered as complimentary imaging in addition to 18-F FDG PET/CT in these conditions. It also explores the potential RGD –based therapy options for these patients.

Abstract ID: 18: Functional imaging with PET/CT in correlation with current standard imaging (MRI) in meningiomas

D. Rajalakshmi, Julie Hephzibah, Saumya Sunny, Junita Rachel John, Justin Benjamin, David Mathew

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Meningiomas are the most common primary intracranial tumours, majority are benign (WHO grade I), showing slow growth and low recurrence. WHO grade II (atypical) and WHO grade III (malignant) are more aggressive. MRI is the 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, while [18F] FDG PET-CT may be useful in tumours that are aggressive with high recurrence and is not widely studied.

Aim: To compare functional imaging ([68Ga] Ga-DOTATATE Vs [18F] FDG PET-CT) in correlation with current standard of imaging (MRI) in management of Meningiomas.

Materials and Methods: Prospective pilot study was conducted between September 2023 – June 2024. MRI brain, [68Ga] Ga-DOTATATE PET-CT and [18F] FDG 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: 10:10, age group range: 31-76 years) were included. Imaging was performed in 17 patients for post-excision assessment and as baseline 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. Compared to [68Ga] Ga-DOTATATE PET-CT, [18F] FDG PET-CT showed uptake in only 1 post-surgical patient with recurrence (CNS Grade 2 MIB 6%) and was negative in the rest.

Conclusions and References: [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. In contrast, the utility of [18F] FDG PET-CT is limited. The limitations of the study are small sample size, single institutional, low number of patients over-all and in high grade group.

Abstract ID: 27: Ga-68 PSMA-11 uptake in multiple myeloma – A case series

Anusha Raju, M. Indirani, S. Shelley

Apollo Hospitals, Chennai, Tamil Nadu, India

Introduction: Prostate-specific membrane antigen (PSMA) is a transmembrane protein mainly associated with prostate cancer, but recent studies have begun exploring its expression in other malignancies, including multiple myeloma (MM). MM is characterized by malignant plasma cell proliferation in the bone marrow, presenting unique challenges for diagnosis and treatment monitoring. Emerging evidence suggests PSMA may be upregulated in the neovascularization linked to MM, prompting interest in its role as a biomarker. This case series aims to investigate the relevance of PSMA in patients with MM and its potential as a novel imaging and therapeutic target.

Materials and Methods: This case series involves two patients who underwent Ga-68 PSMA PET/CT at our tertiary care center. The first case had a confirmed dual malignancy of prostate adenocarcinoma and MM, with a bone marrow aspirate revealing 27% plasma cells. His serum PSA level was 2.1 ng/mL, and had an elevated free lambda value. He was on hormonal therapy for prostatic cancer. The second case presented with weight loss and lower urinary tract symptoms. Blood tests indicated elevated serum PSA levels (64 ng/mL) and a reversed albumin-globulin ratio. Both patients received an injection of 111-259 MBq of Ga-68 PSMA, and PET/CT scans were performed 50-100 minutes later.

Results: In Case One, elevated PSMA uptake was noted in the prostate (SUVmax 6.4) along with multiple tracer-avid myelomatous lesions (SUVmax 13.1). Case Two exhibited a PSMA-avid prostatic lesion (SUVmax 20.8) and several lytic and marrow lesions with increased tracer activity (SUVmax 15.8). Further evaluations revealed elevated free lambda and beta-2 microglobulin levels, with a bone marrow aspiration cytology indicating 25% plasma cells, confirming MM. A TRUS-guided biopsy of the prostate identified acinar adenocarcinoma (Gleason score 3+3=6). The patient was placed on active surveillance for prostate cancer while starting chemotherapy for MM.

Conclusions and References: This case series highlights that PSMA uptake can occur in MM, emphasizing the need for careful clinical correlation when interpreting PSMA PET/CT results. Significant PSMA uptake in myelomatous lesions may lead to PSMA-targeted theranostic strategies, providing new diagnostic and therapeutic opportunities. However, further research with larger sample sizes is necessary to clarify PSMA’s role as a biomarker in this context.

Abstract ID: 71: To optimise the PET acquisition time per bed position for low count rate radioactive studies

Sandra Maria Ignatious, P. Aadhavan, Prabu Titus Devakumar, Julie Hephzibah, Saumya Sara Sunny, Junita Rachel John

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: PET-CT imaging is crucial for diagnosing and monitoring various diseases. The commonly used tracer, 18F FDG (Fluorodeoxyglucose), benefits from new-generation Time-of-Flight (TOF) PET/CT systems, which enhance spatial and coincidence time resolution. It is acommon understanding that longer acquisition time is required when low radioactivity is used for improved image resolution. This study explores how acquisition time and reconstruction parameters affect image quality and quantitative accuracy in low count rate scenarios using a NEMA IQ phantom.

Aim: To optimize the pet acquisition time per bed position for low count rate radioactive studies.

Materials and Methods: Using the NEMA IQ body phantom with a lung insert and six spheres of different sizes, 71±3 MBq of 18F FDG was administered. PET images were acquired at various bed positions with acquisition times of 30, 60, 120, 150, 180, 210, 240, and 300 seconds, with 300 seconds as the reference. Volume of Interest (VOI) analysis assessed image quality via Contrast-to-Noise Ratio (CNR) and Coefficient of Variation (CV%), while quantitative accuracy was evaluated through Standardized Uptake Values (SUV). A selected dataset was reconstructed with different Full Width at Half Maximum (FWHM) values ranging from 4 mm to 7 mm.

Results: Longer acquisition times improved CNR and reduced CV%. Iterative + TOF reconstruction with 4 to 5 mm FWHM provided optimal image quality. The optimal acquisition time was determined to be around 180 to 210 seconds per bed position for low count rate radioactive studies.

Conclusions and References: In general clinical practice, longer acquisition times (300 seconds) per bed position was used to improve image quality. Our study highlighted that reducing scan time further to 180 to 210 seconds per bed position in low count radioactive studies can be followed as there is no compromise on the image quality and lesion detectability. This reduction in overall scan duration will reduce patient movement related artefact and enhance efficient time management in daily work practice.

Abstract ID: 79: In silico study of integrin antagonist carbamate-DOTA-Ga binding with PD-L1: A theranostic approach for cancer immunotherapy

Deepanshu, Jaya Shukla¹, Sejal Chopra

Post Graduate Institute of Medical Education and Research, ¹Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: The interaction between PD-L1 and its receptor PD-1 is a key mechanism through which cancer cells evade the immune system. Targeting this pathway has become central to cancer immunotherapy. This study aims to explore the binding interaction between PD-L1 and an integrin antagonist carbamate (IAC) conjugated with DOTA-Gallium (68Ga), a compound with both therapeutic and diagnostic potential. Using molecular docking, the objective is to evaluate the binding affinity and interaction patterns between PD-L1 and IAC-DOTA-68Ga, offering insights into its potential as a dual-function theranostic agent for cancer treatment and imaging.

Materials and Methods: Molecular docking was performed to evaluate the interaction between PD-L1 and the integrin antagonist carbamate (IAC) conjugated with DOTA-Gallium (68Ga). The 3D structure of PD-L1 was retrieved from the Protein Data Bank (PDB). The ligand structure was modeled and optimized. AutoDock Vina was used for the docking simulation, with the PD-L1 binding site defined within a grid box. The best binding pose was selected based on the docking score, which was -9.1 kcal/mol, indicating a strong affinity. The docking results were analyzed for hydrogen bonding and hydrophobic interactions between PD-L1 and IAC-DOTA-68Ga.

Results: Molecular docking of the integrin antagonist carbamate-DOTA-Gallium (IAC-DOTA-68Ga) with PD-L1 was performed using AutoDock Vina, yielding a binding energy of -9.1 kcal/mol, indicating strong affinity between the two molecules. Analysis of the docking pose revealed that IAC-DOTA-68Ga fits well within the PD-L1 binding site, forming key interactions. Hydrogen bonding and hydrophobic interactions were observed between the compound and amino acid residues in the PD-L1 binding pocket, suggesting effective inhibition of the PD-L1/PD-1 interaction. The stable binding indicates potential for IAC-DOTA-68Ga as a theranostic agent, with Gallium enabling PET imaging, and the integrin antagonist carbamate offering therapeutic potential by disrupting immune checkpoint signaling. These findings support further experimental validation to assess its efficacy as both a cancer diagnostic and treatment tool.

Conclusions and References: This study explored the interaction between PD-L1 and integrin antagonist carbamate-DOTA-Gallium (IAC-DOTA-68Ga) using molecular docking techniques. The docking results revealed a strong binding affinity with a docking score of -9.1 kcal/mol, indicating that IAC-DOTA-68Ga can effectively bind to the PD-L1 binding pocket. The identified hydrogen bonds and hydrophobic interactions suggest that the compound may successfully inhibit the PD-L1/PD-1 interaction, which is a key mechanism of immune evasion in cancer. Additionally, the radiolabeled Gallium component provides imaging potential through positron emission tomography (PET). These findings suggest that IAC-DOTA-68Ga holds promise as a theranostic agent, offering both therapeutic and diagnostic capabilities in cancer treatment. Future in vitro and in vivo studies are necessary to confirm its clinical efficacy.

Abstract ID: 90: Utility of FDG PET/CT in evaluating extent and treatment response in Rosai-Dorfman disease: Insights from nuclear medicine

Kapish Jain, Mohammad Umar, Anushna S. Babu, Sambit Sagar, Dikhra Khan, Rakesh Kumar

AIIMS, New Delhi, India

Introduction: The aim of the study is to evaluate the role of FDG PET/CT to know the extent of disease and evaluating treatment response in biopsy proven cases of Rosai-dorfman disease.

Materials and Methods: At a tertiary care center in India, we conducted a retrospective study that included 12 patients referred to our department with biopsy proven Rosai-dorfman disease for baseline staging between January 2018 and June 2024. Following chemotherapy, 9 patient underwent repeat FDG PET/CT scans to assess treatment response according to PERCIST 1.1. Patient information was collected from our database, and all patients underwent 18F FDG PET/CT according to our department protocol. Two experienced nuclear medicine physicians reviewed the scans done at the time of initial staging and post induction chemotherapy.

Results: Out of 12 patients included in study, 8 were male and 4 were female with a median age of (14.5+/-13.33 yrs) with involvement of lymph nodes {cervical (11/12), mediastinal (6/12), axillary (4/12), abdomino-pelvic (8/12) patients}, subcutaneous nodules (3/12), bones (3/12), spleen (2), intraorbital (1), lung (1), marrow (1) and liver (1) patient. Response evaluation of 9 patients done after therapy and results demonstrated a significant reduction in metabolic activity in all the 9 patients with a decrease in standardized uptake values (SUVs) indicating effective response to therapy. Three patients exhibited complete metabolic response (CMR), while the remaining showed partial responses.

Conclusions and References: In rare disease like Rosai-dorfman 18F FDG PET/CT can be a potential modality to know the extent of disease and also in monitoring treatment efficacy, providing valuable insights that can inform clinical decision-making.

Abstract ID: 98: Functional metabolic imaging of the spinal cord using 18F-FDG PET/CT – Where do we stand in the “PET era of oncology”?

Srinivas Ananth Kumar

Nizam’s Institute of Medical Sciences, Hyderabad, Telangana, India

Introduction: Recognition of the physiologic distribution of 18F-FDG in the spinal cord is pivotal for accurate interpretation, with disparate challenges due to its small size, relatively low resolution of PET images, and contamination from the adjacent vertebral bone marrow, particularly in oncological patients. This study aimed to investigate the normal distribution of FDG in the spinal cord.

Materials and Methods: This retrospective, observational study included patients who were referred for FDG PET/CT both for oncological (predominantly) and non-oncological indications. Presence of motion between PET and CT datasets with failed/poor co-registration, patients with known spinal canal or cord diseases, deranged hemoglobin values and blood sugar levels were excluded. A circular region of interest (ROI) of 3mm radius was centered on the spinal cord and the corresponding vertebral body bone marrow. SUVmax, SUVmean and normalized SUVmax & SUVmean values were calculated.

Results: 100 patients (49 males and 51 females) were included in this study with a mean age of 52.3 years (SD ±14.2), who were clubbed into three groups arbitrarily based on the age into < 40 years, 40-70 years and > 70 years. 47% of the study population was between 40-70 years of age. 42.8% of males and 43% females were in the 40-70 years age group. All patients had normal hemoglobin levels [males and females with a mean value of 14.3 g/dl (SD ± 0.4) and 12.1 g/dl (SD ± 0.7) respectively] with mean serum blood glucose level of 148 mg/dl. A mean dose of 7.8 mCi (SD ± 2.4) of 18F-FDG was injected to the patients with a mean time to imaging of 69 minutes (SD ± 13). Average SUVmax values of the cervical segments of the spinal cord were 1.8 (SD ± 0.4), 1.7(SD ± 0.5), 2.1(SD ± 0.5) and 2.2 (SD ± 0.5), 2.3 (SD ± 0.7), 2.1(SD ± 0.5) in the 3 separate age groups in males and females respectively. Similarly, average SUVmax and SUVmean values with and without normalization were calculated for upper thoracic and lower thoracic spinal cord segments. Decreasing pattern of FDG uptake from cervical to lumbar vertebrae was noted with two sporadic maxima at the lower cervical (C6) and lower thoracic (T12) levels with a mean SUVmax of 2.1 (SD ± 0.5) and 2.2 (SD ± 0.6) respectively.

Conclusions and References: Focal hypermetabolism of the spinal cord at the level of lower thoracic and lower cervical vertebrae should be regarded physiological unless proven otherwise.

Abstract ID: 102: Unveiling critical emergencies on 18F FDG-PET/CT: Moving beyond oncologic boundaries

Tanvi Sarwal, Sameer Taywade, K. M. Althaf, Rajesh Kumar

All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Introduction: Occasionally, unexpected critical findings are identified on routine 18F flourodeoxyglucose positron emission tomography/ computed tomography (18F FDG-PET/CT) scans, which may require immediate intervention. We evaluated emergency findings detected unexpectedly on 18F FDG-PET/CT in a tertiary care hospital in Western India.

Materials and Methods: 18F FDG-PET/CT scans performed for various oncological and non-oncological indications between February 2021 and September 2024 were retrospectively reviewed. Specific keywords were used to identify emergency conditions. Patients who had known critical findings before undergoing PET/CT were excluded from the study.

Results: Out of 5450 whole-body PET/CT scans reviewed using specific keywords, incidental emergency findings were detected in 33 patients (0.6%). The mean age was 53.7 years, with 20 males and 13 females. Of the 33 scans reviewed, 25 were performed for oncological indications (15 baseline, 10 post-chemotherapy), 5 were for pyrexia of unknown origin and 3 were for neurological conditions. The oncological cases included gastrointestinal cancers (10 patients), gynaecological cancers (5 patients), lung cancer (3 patients), paraneoplastic/ unknown primary (3 patients), genitourinary cancers (2 patients) and head & neck cancers (2 patients). The emergency findings detected on PET/CT included abdominal aortic aneurysm (3 patients), carcinoma esophagus with perforation into lung (3 patients), acute intestinal obstruction (3 patients), acute appendicitis (3 patients), acute cholecystitis (3 patients), diffuse hypometabolism in brain indicating neurological emergency (3 patients), cerebral aneurysm (2 patients), discitis (2 patients), tumor thrombus extending into vena cava and right atrium (2 patients), septic embolus in brain (1 patient), rectal perforation (1 patient), pneumoperitoneum (1 patient), brain hematoma (1 patient), renal subcapsular rupture with hematoma (1 patient), rupture of liver tumor (1 patient), necrotising fasciitis (1 patient), space occupying lesion in brain causing midline shift (1 patient) and large aortic root pseudoaneurysm (1 patient). The patients were followed up to assess whether the critical PET/CT findings influenced clinical decision making. A change in management occurred in 50% of the cases, highlighting the significance of these findings.

Conclusions and References: The highest rate of emergencies was observed in patients undergoing staging PET/CT for gastrointestinal cancers. Incidental findings highlight the need for careful evaluation, as early detection can significantly impact patient management. Reporting should not be focused on just oncology findings, nuclear medicine physicians should be vigilant about the other associated potential complications that may need prompt attention of the referring physician. This will ensure timely intervention for these serious and urgent conditions.

Abstract ID: 121: To establish a cutoff to determine paucity of inguinal lymph node in the patients with bilateral limb swelling

Ayan Dhiman, Sambit Sagar, Dikhra Khan, Goriparti Lalitha, Roshan Karna, Rakesh Kumar

All India Institute of Medical Sciences, Delhi, India

Introduction: Lymphatic obstruction is an abnormal build up of fluid containing proteins in interstitium due to blockage of lymphatic system normal drainage function. It leads to increase in the protein content of extravascular tissue resulting in water retention and swelling of soft tissues. The rise in the proteins outside the blood vessels triggers fibroblast growth, fluid organization and the development of non-pitting edema in the affected limb. For the evaluation of lymphatic system lymphoscintigraphy can be used to confirm the diagnosis of lymphedema, extent of involvement and for any therapeutic intervention.

Materials and Methods: 142 cases of lymphedema referred to our center in nuclear medicine department for lymphoscintigraphy. Acquisition of lymphoscintigraphy was performed on dedicated gamma cameras (Mediso Anyscan S and GE HealthCare – discovery 630) after administration of 1 mCi in I ml solution of 99mTc-Sulphur colloidepifascial injection in the web spaces of feet. All the scans were interpreted by two experienced nuclear medicine physicians.

Results: A total of 142 patients with diagnosed lower limb swelling (unilateral or bilateral) were included in the study. All patients underwent lymphoscintigraphy imaging after receiving standard treatment regimens. The mean age was 36.97 years with males 73 and females 69. Of 142 patients who came with lower limb swelling, 27 patients with left lower limb partial obstruction shows 2609.22 ± 514.9 counts in left lower limb, 14575.74 ± 9298.53 counts in normal right lower limb and 226 ± 39.7 average background counts, 21 patients with right lower limb partial obstruction shows 3581.4 ± 1280.03 counts in right lower limb, 4694 ± 1627.6 counts in normal left lower limb and 130 ± 17.8 average background counts, 10 patients with leftlower limb complete obstruction shows 6000 ± 1345.4 counts in normal right lower limb, 898.9 ± 539.6 in left lower limb and 203.4 ± 39.7 average background counts, 8 patients with right lower limb complete obstruction shows 376.8 ± 157.6 counts in right lower limb, 6865.2 ± 1841.5 counts in normal left lower limb and 261.3 ± 95.6 average background counts, 13 patients with bilateral lower limb obstruction shows 4507.3 ± 1297.6 counts in right lower limb, 3958 ± 1646.9 counts in left lower limb and 151.5 ± 24.07 average background counts and 63 patients with bilateral patent limb shows 7551.04 ± 1068.69 counts in right lower limb, 7089.09 ± 973.97 counts in left lower limb and 192.77 ± 20.9 average background counts. A cutoff was determined as the mean ± 2 SD for paucity of lymph node according to the swollen limb.

Conclusions and References: The data shows that patients with partial and complete obstructions have significantly different counts in the obstructed limbs compared to normal limbs and background counts. To establish a cutoff for partial obstruction, further analysis and validation with the larger datasets and clinical correlation are needed.

Abstract ID: 137: A systematic analysis of the role of the IAEA in improving the access to nuclear medicine in the low- and middle-income countries

M. Jhanani

School of Excellence in Law, Tamil Nadu Dr. Ambedkar Law University, Chennai, Tamil Nadu, India

Introduction: The first clinical application of nuclear medicine was made in 1936 by Dr. John H. Lawrence, who used Phosporous-32 in the treatment of leukemia. Since then, we have observed the presence of nuclear medicine in almost every branch of modern medicine. Despite the importance of nuclear medicine, we find the problem of limited access to diagnostic and therapeutic modalities, especially in the Low- and Middle- Income Countries (LMICs). This has primarily been due to financial constraints, insufficiency of technical knowledge and other limitations. The International Atomic Energy Agency (IAEA) has been working tirelessly to address these challenges faced by the LMICs through various programmes. This has been done through facilitating access to diagnostic equipment, publication of technical manuals, training of human resources, monitoring the quality of nuclear medicine facilities, and so on.

Objective: This article seeks to explore the effectiveness of the IAEA’s efforts in improving the access to nuclear medicine in the LMICs, while also analyzing the challenges involved in the access to nuclear medicine and the improvements which can be made to further address these challenges.

Materials and Methods: A non-empirical study was conducted using secondary data sources, including books, articles, databases (namely- GLOBOCAN, IMAGINE, NUMDAB, NUCLEUS), IAEA periodicals and press releases.

Results: Although there have been significant contributions by the IAEA in improving access to diagnostic and therapeutic modalities of nuclear medicine, the effectiveness of the IAEA’s efforts has been hampered by challenges including regulatory constraints and financial limitations. Despite these limitations, the IAEA has been successful in its mission in the LMICs, while also being beneficial to the nuclear medicine programmes of other economically developed countries as well. The limitations faced by the IAEA can be addressed through an improved participation and cooperative behavior of the governments of these countries. Furthermore, an increase in the engagement of private players especially companies involved in the manufacture of radiopharmaceuticals and diagnostic equipment through private-public partnerships can further improve the access to nuclear medicine facilities in the LMICs.

Conclusions and References: It is concluded that while the IAEA has been playing a key role in improving access to nuclear medicine, a holistic participation of all stakeholders is essential for a more significant increase in the access to nuclear medicine in the LMICs.

Abstract ID: 151: Establishing patient criteria for the study of sodium iodide symporter and pendrin in various thyroid cancer types

Chandrakala Gholve, Yogita Shete, Swapnil Rane, Roopal Agrawal, Smita Gawandi, S. Basu, N. S. Baghel

Radiation Medicine Centre, BARC, Mumbai, Maharashtra, India

Introduction: Sodium iodide symporter (NIS) and pendrin (PDS) are pivotal iodide transporters in thyroid tissue, essential for iodine metabolism and hormone synthesis. Despite their significance, the molecular mechanisms leading to the impaired iodide uptake in thyroid tumors remain inadequately understood. By elucidating the expression and localization of NIS and pendrin in the context of thyroid cancer, this study aims to shed light on the underlying alterations that contribute to iodine metabolism deficiencies. Understanding these dynamics is critical, as diminished iodine uptake poses significant therapeutic challenges, particularly in the management of radioactive iodine refractory (RAI-R) thyroid cancers. Our study aims to establish patient criteria for the study of sodium iodide symporter and pendrin in various thyroid cancer types.

Materials and Methods: This study will employ immunohistochemistry to accurately localize NIS and pendrin within human thyroid tissue samples obtained from patients diagnosed with papillary, follicular and poorly differentiated thyroid carcinoma. We will categorize participants into two groups based on their radioactive iodine (RAI) uptake status in residual or metastatic lesions: those demonstrating significant uptake and those with negative iodine scans. Our retrospective case-control design will encompass approximately 100 patients aged 18 to 70 who underwent total thyroidectomy followed by RAI therapy between January 2010 and December 2020. Detailed clinical data will be collected, including age, gender, clinical and pathological staging, treatment history, final histopathology reports, and follow-up outcomes. Histopathological evaluations will confirm the cancer type, ensuring a comprehensive patient cohort analysis.

Results: As per the experimental design, so far, we have included a total number of 80 patients with thyroid carcinoma, who had evidence of residual or metastatic disease on biochemical, clinical, or imaging parameters. The study includes 40 (M=20, F-20) patients with significant uptake and 40 patients with no uptake (M=20, F-20) on a radioiodine scan. The age group for the female and male patients ranges from 27-67 years and 33-69 years respectively. All the patients had undergone total thyroidectomy as the primary mode of treatment followed by subsequent low-dose I-131 scans and radionuclide therapies.

Conclusions and References: The insights gained from this research could pave the way for the development of innovative therapeutic strategies, including redifferentiation protocols or combination treatments that may restore iodine avidity in cancer cells. Ultimately, this study seeks to enhance the understanding of thyroid cancer biology, providing a foundation for improved patient management strategies in the face of iodine concentration challenges.

Abstract ID: 185: Uncommon presentation of a mesenchymal tumor brought to light with SSTR imaging

Vignesh, Harish Goyal, Dhanapathi Halanaik

JIPMER, Puducherry, India

Introduction: Tumor induced osteomalacia (TIO) is a rare paraneoplastic syndrome arising due to the secretion of phosphaturic factors such as fibroblast growth factor 23 (FGF 23). FGF secreting tumors are commonly small mesenchymal tumors. Phosphaturic mesenchymal tumor mixed connective tissue variant (PMTMCT) tumors are associated with 70-80% of TIO cases. Hemangiopericytomas are mesenchymal tumors which are known to produce TIO. They are also known to cause paraneoplastic hypoglycemia due to secretion of IGF-2. Hemangioblastomas are uncommon neoplasms of the central nervous system usually occurring in the cerebellum, spinal cord and brainstem. A known paraneoplastic presentation is in the form of paraneoplastic erythrocytosis.

Results: Here, we present a 43 year old male patient who presented with complaints of difficulty in walking. Serum electrolytes showed hypophosphatemia (1.29 mg/dL) and mildly elevated ALP (250 IU/L). Serum intact PTH was within normal limits. 24 hour urine phosphate levels were not obtained. Due to a clinical suspicion of TIO, SSTR and FDG PET/CTs were performed which revealed: SSTR expressing, metabolically inactive lesion in the right cerebellopontine angle - likely meningioma/hemangiopericytoma; SSTR expressing, metabolically active lytic lesions lesions in the right proximal fibula and left proximal radius; and, low grade SSTR expressing, metabolically active lytic lesions in multiple bilateral ribs and left ramus of mandible - likely secondary to TIO. MRI findings revealed a solid extra-axial lesion in the right cerebellopontine angle, suggesting the possibility of a schwannoma. On histopathological examination and immunohistochemical staining, the lesion was identified to have features of hemangioblastoma.

Conclusions and References: SSTR expressing intracranial tumors include meningioma, hemangiopericytoma (soft tissue fibroma), pituitary neuroendocrine tumors (NETs) and intracranial NETs. The SSTR and MRI findings point towards a solid mesenchymal tumor. In contrast histopathology suggested a predominantly cystic tumor which has not been documented as a cause of TIO. This case was a diagnostic challenge due to the uncommon location of a hemangiopericytoma and uncommon MRI findings of a hemangioblastoma. Hemangioblastoma as a cause of TIO has not been documented in literature. Our drawback was the unavailability of FGF 23 values. Further studies about the possibility of hemangioblastoma as a cause of TIO are required. In conclusion, this case highlights the importance of a multidisciplinary/multimodality approach in the evaluation of an uncommon presentation of a tumor causing TIO.

Abstract ID: 192: Medium vessel vasculitis revealed on FDG PET scan as cause of pyrexia of unknown origin

Janpreet Singh

P. D. Hinduja Hospital and Medical Research Centre, Mumbai, Maharashtra, India

Introduction: Vasculitis is a heterogeneous group of disorders characterized by inflammation of blood vessel walls, leading to tissue ischemia and damage. While FDG PET-CT has established itself as a vital tool in large vessel vasculitis, its utility in detecting medium vessel vasculitis (MVV) remains less well-documented. MVV, which includes conditions like polyarteritis nodosa, often presents with non-specific symptoms such as fever of unknown origin, making diagnosis challenging. FDG PET-CT can play a crucial role in identifying inflammatory activity in medium-sized vessels, thus guiding timely therapeutic interventions. These case reports highlight the detection of medium vessel vasculitis in pyrexia of unknown origin using FDG PET-CT scan, emphasizing the modality’s diagnostic value in such clinically ambiguous cases.

Materials and Methods: We present two adult patients with pyrexia of unknown origin detected with medium vessel vasculitis in lower extremities on whole body FDG PET-CT imaging.

Results: Following initiation of corticosteroid therapy, significant clinical improvement was observed, which was also reflected on response FDG PET-CT scan in one of the patients.

Conclusions and References: Our case report highlights the role FDG PET-CT in medium vessel vasculitis, particularly in cases with non-specific systemic symptoms, thus enabling early diagnosis and treatment, and also monitoring treatment response.

Abstract ID: 210: Assessment of similarities among the original radiomic features in various disease group using clustering method

Sushmita Mahachandra Singh, Umesh B. Sherkhane, Nilendu Purandare, Ashish Kumar Jha, Venkatesh Rangarajan

Department of Nuclear Medicine and Molecular Imaging Technology, Tata Memorial Centre, Navi Mumbai, Maharashtra, India

Introduction: In last one-decade radiomics has been utilized as imaging biomarker to predict outcomes in cancer. However, these features can be redundant, leading to overfitting in prediction models. This study aims to analyse radiomic features across different diseases to identify similarities and potential correlations, helping to avoid redundancy and improve feature selection in model development.

Materials and Methods: This study included 97 patients of lung (28), cervical (23), and rectal (46) cancer who underwent pretreatment PET/CT scans in our department. All the CT images of the patients were loaded on the EBW Workstation Philips Healthcare Limited and tumor delineation was performed. CT Radiomic features were extracted using PyRadGUI software. Subsequently, radiomic features were analysed to know the association among them using K-Means clustering techniques in Python 3.12.3.

Results: A total of 1093 features were extracted from each set of images, utilizing only original features for the study. Two sets were considered: one involved randomly selecting 5 clusters, while the other involved plotting Silhouette scores for each disease group, resulting in 2 clusters. After performing K Mean clustering, features were divided among the clusters for both sets. Upon intersecting clusters of Set 1 lung and rectal cancer, a total of 13 features were found to be common; for rectal and cervical cancer, 29 features were common; and for cervical and lung cancer, 12 features were common. Additionally, when intersecting clusters of all three disease groups, 3 common features were identified. Similarly, for Set 2, 65 features were common between lung and rectal cancer, 43 features between lung and cervical cancer, and 25 features between rectal and cervical cancer. After intersecting clusters of all three disease groups for Set 2, 17 features were found to be common.

Conclusions and References: From our study we found some features that were shared across all diseases, and also some unique features to each disease group. These shared and unique features can help us to make prediction models in future.

Abstract ID: 213: Repeatability and reproducibility of averaging computed tomography radiomics: A phantom study

Madhuri Anil More, Umesh B. Sherkhane, Nilendu Purandare, Ashish Kumar Jha, Venkatesh Rangarajan

Department of Nuclear Medicine and Molecular Imaging Technology, Tata Memorial Centre, Navi Mumbai, Maharashtra, India

Introduction: The repeatability and reproducibility of radiomics features extracted from CT scans need to be investigated. Only robust and stable features should be used in prognostication/prediction models to improve generalizability across multiple institutions. Aim of this study is to access the temporal stability of imaging features with respect to a controlled scenario (test–retest), as well as their dependence on acquisition parameters such as slice thickness, or tube current.

Materials and Methods: The PET NEMA IQ phantom was filled with water and image acquisition of phantom performed on two PET/CT scanner (Scanner1: Gemini TF16, Scanner 2: Gemini TF16) by changing imaging parameters to check reproducibility and test were repeated in 30 min coffee break (TEST-Retest) to check repeatability of the radiomic feature. CT image acquisition performed using constant tube voltage i.e. 120 kVP and changing tube current to 100 mAs, 200 mAs, and 300 mAs and changing slice thickness to 2 mm and 5 mm. Scans were repeated after 30 min. The largest sphere (i.e. 37 mm diameter) was contour on Philips IntelliSpace Discovery workstation and saves as RT-Struct for all the image sets. The original CT images were preprocessed and 1080 radiomics features extracted from RT-Struct using PyRadGUI software. The average of 90 first order and textural features were calculated which were extracted from original image (1 set), LoG filtered image (3 sets) and wavelet images (8 sets). The repeatability and reproducibility of original and average radiomics features calculated using Inter Class Correlation (ICC.) The radiomics features classified based on ICC range as an Excellent (ICC >0.9), Good (0.9 > ICC >0.75), Moderate (0.75 > ICC > 0.5), and poorly (ICC<0.5) correlated features.

Results: In repeatability (Test-Retest) study performed for original radiomics features obtained for scanner 1, scanner 2 and combining (scanner 1& 2), the 77%, 51% and 43% features showed excellent correlation. In reproducibility study (inter scanner variability) performed for original 25.55% radiomics features presented with excellent correlation. In repeatability (Test-Retest) study performed for average radiomics features obtained for scanner 1, scanner 2 and combining (scanner 1& 2), the 81.11%, 57.77%, and 76.66% features showed excellent correlation. In reproducibility study (inter scanner variability) performed for original 54.44% radiomics features presented with excellent correlation.

Conclusions and References: Our study demonstrates that average radiomic features are more robust in comparison of original features. The robust features need to be investigated further in larger sets of data and also for its utility to develop prognostic and predictive models.

Abstract ID: 7: Evaluation of uncommon factors with potential influence on the yield of Ga68 labelled radiopharmaceuticals in fully automatic Ge68-Ga68 generator synthesis module

S. V. Ramanamurthy, K. B. Sricharan, K. Rajakumar, K. Jaya Udayasekhar

Homibhabha Cancer Hospital and Research Centre, Visakhapatnam, Andhra Pradesh, India

Introduction: In recent years the application of Ga68 labelled radiopharmaceuticals like PSMA (prostate specific membrane antigen), DOTA-TOC (1, 4, 7, 10 -tetra azacyclododecane 1, 4, 7, 10 tetra acetic acid) and FAPI (Fibroblast activation protein inhibitor) has increased for PET-CT in nuclear medicine practice. Ga68 is available from Ge68-Ga68 generator because of its physical, chemical and radioactive decay properties. Ga68-labelled radiopharmaceuticals prepare by manual semiautomatic and automatic synthesis module methods. This study aimed to investigate uncommon factors were may influence and give inconsistent radiochemical yield.

Materials and Methods: In general, the radiochemical synthesis yield (RCY) is the important indicator for the efficiency of the synthesis process. A high and Radiochemical yield is desirable, although it may not be always attainable under the same physiochemical conditions and the same synthesis sequence. Synthesis procedures were doing as per manufacturers protocols.

Results: Generally basic factors that directly affect synthesis efficacy (reaction time, temperature and reagents concentration). This study aimed to evaluate the factors and variances other than ones with major impact, which can notably affect the production yield in everyday practice.

1. Incomplete Elution of Ga-68 -Cl3 due to low pressure and volume of elution

2. No proper transfer of Ga68-labelled peptide into the trapping cartridge

3. Low recovery of Ga68-labelled product due to leakage of elution solution or not properly preconditioning of trapping cartridge

4. Failure synthesizer communication (communication dropping)

5. Defects of the cassettes despite the completed cassette self-test, such as cassette leakage, blocking of a valve and also long usage of reagent set may impact on the final product of Ga68 labelled radiopharmaceuticals and production yield (< 60%).

Conclusions and References: This small study evaluated how different potential factors, other than key factors impact on radiosynthesis efficiency and give inconsistent Ga68-labelled production yield.

Abstract ID: 160: Impact of image reconstruction setting of FWHM in Gaussian filter in PET/CT

R. Oliver Brice, K. K. Kamaleshwaran, E. Ramkumar, R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of the study is to see impact of image reconstruction settings full width at half maximum (FWHM) shifting of Gaussian filter Image Quality and Quantification in PET/CT Imaging of Patients with High Body Mass Index (BMI). Positron Emission Tomography/Computed Tomography (PET/CT) is a critical imaging modality used in oncology for diagnosis and treatment planning. The Full Width at Half Maximum (FWHM) setting plays a pivotal role in determining image quality and spatial resolution. This study investigates the effects of varying FWHM settings on image quality in patients with high body mass index (BMI), specifically focusing on obese and overweight individuals.

Materials and Methods: A cohort of 10 patients, All classified as obese patient with the BMI above 31.7 kg/m2 and overweight patient with the BMI of above 26.36 kg/m2, underwent PET/CT scans utilizing different FWHM settings: 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm. Each patient was imaged under these conditions to assess the impact of FWHM variations on image quality, spatial resolution, and standardized uptake values (SUV). Image quality was evaluated through qualitative and quantitative metrics, including signal-to-noise ratio (SNR) and spatial resolution assessments.

Results: The results indicated that the 5 mm FWHM setting provided optimal image quality, yielding superior spatial resolution and favorable SUV values compared to the other settings. The 4 mm and 6 mm settings demonstrated moderate improvements, while the 2 mm and 7 mm settings resulted in diminished image quality due to increased noise and decreased resolution.

Conclusions and References: The findings of this study confirm that the standard 5 mm FWHM setting in PET/CT scanners significantly enhances image quality and spatial resolution in obese and overweight patients.

Abstract ID: 173: Phantom-based standardization of SPECT imaging for accurate quantitative analysis

Ajay Kumar, Amritjyot Kaur, Sarika Sharma Prashar, Baljinder Singh

Post Graduate Institute of Medical Education and Research, Chandigarh, India

Introduction: Standardization through phantom studies is essential before patient enrolment to ensure accurate measurement of volume and radioactivity concentration. This study aimed to establish threshold values for converting pixels activity into accurate volume and radioactivity concentration measurements using a SPECT phantom.

Materials and Methods: A series of experiments were performed using the Jaszczak SPECT phantom to calculate threshold values for maximal pixel activity. Radioactivity concentrations ranging from 0.77 µCi/mL to 4.09 µCi/mL were analysed across varying volumes (6.0 to 3200 mL). The SPECT imaging was performed using a dual-headed gamma camera (Symbia-T16, SIEMENS) over 360° with 120 projections (20 sec/projection) in a 128 x 128 matrix. The acquired data was reconstructed using iterative reconstruction with a Butterworth filter (cut-off: 0.5 cycles/cm). Threshold values were varied from 19 to 52 on attenuation and non-attenuation corrected images across different volume ranges to determine optimal settings.

Results: Threshold was calculated using 3D volumetric analysis 8.5.10.1 Software. For attenuation-corrected SPECT images, the optimal threshold values were determined to be 41, 38, and 33 for activity volumes of 6.0–30.0 mL, 500.0–2000.0 mL, and 2400–3200 mL, respectively, yielding significant correlations (p=0.001) of 0.90, 0.98, and 0.97. For non-attenuation-corrected images, the optimal threshold values were 40, 37, and 39, showing similarly high correlations (p<0.0001). Using the 38.0% threshold, for volumes ranging from 500.0–1500.0 mL, the SPECT measurements of radioactivity concentrations (counts/cc) showed a strong correlation (r=0.98, p<0.001) with actual concentrations (µCi/cc). The regression equation obtained was A = 6807.3 × B + 396, where A represented the SPECT-measured concentration (counts/cc) and B; the actual concentration in µCi/cc. Similarly, another regression lines may be obtained for lower and higher volume ranges. Using this regression line equation counts/cc can be converted into activity concentration (µCi/cc). The %ID/mL can be calculated by multiplying the activity concentration (µCi/cc) with the injected activity. Finally, % quantitative uptake can be determined by multiplying the organ volume with the %ID/mL, providing precise functional assessments.

Conclusions and References: This study successfully standardized the conversion of SPECT pixel activity to volume and radioactivity concentration through phantom imaging. The 38% threshold value, for volume 500-2000 mL, representing typical liver volumes, may enhance the accuracy of patient studies, ensuring reliable diagnostic outcomes and more precise quantitative uptake measurements.

Abstract ID: 186: Assessment of imaging quality in Lu-177 peptides: Low versus high-energy collimators

Gadol D. Shine, T. D. Prabu, Julie Hephzibah, Junita Rachel John, Saumya, P. Aadhavan

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: 177Lu (T ½: 6.67 days) is a reactor produced radioisotope that decays with beta minus emissions yielding beta particles (Emax of 498.3 keV) and gamma rays of energy 208 keV (10.4%) and 113 keV (6.4%). In Clinical Nuclear medicine, Lu177 when tagged with peptides like DOTA, PSMA is useful for the treatment of neuroendocrine tumors (NET) and Ca prostate respectively. Post therapy scans are acquired in the gamma camera for confirmation of radiopharmaceutical localization in the areas of disease and it is desirable to have reasonably good image quality for the same. This study was done to assess the effect of the type of collimator in acquiring optimal image quality.

Aim: To compare the image quality of Lu177 post therapy scans with Low Energy High Resolution (LEHR) and High Energy General Purpose (HEGP) collimators by analyzing system sensitivity and spatial resolution.

Materials and Methods: A sensitivity analysis for Lu177 was conducted using the Siemens Evo Excel gamma camera, with an activity of 1.074 mCi (Lu177) utilizing a petri dish positioned 10 cm from the detector. Images were acquired over a duration of 1 minute, repeating 5 static acquisitions on both collimators. Region of interest (ROI) was drawn around the petridish and sensitivity was calculated. Later, spatial resolution analysis was performed on the same gamma camera using 4.42 mCi of Lu177. Flood field phantom and four quadrant bar phantom images were acquired on count basis, over 3 million counts on both collimators.

Results: The sensitivity values for the LEHR collimator were obtained as follows: LEHR (Det-1(114 cpm/ µCi) (Det-2(115 cpm/ µCi). For the HEGP collimator, the values acquired were: HEGP (Detector1-17 cpm/µCi, Detector 2 – 16 cpm/µCi). In terms of spatial resolution, the LEHR produces images with a lower resolution than the HEGP collimator.

Conclusions and References: The LEHR collimator exhibited significantly higher sensitivity compared to the HEGP collimator. However, the resulting images were highly scattered, and the spatial resolution was very low. Conversely, the sensitivity of the HEGP collimator was lower, it produced much better spatial resolution than the LEHR collimator. This suggests that we can use the HEGP collimators instead of the LEHR collimator for Lu177 imaging in gamma camera.

Abstract ID: 190: Comparative performance assessment of multiple well counters

Manojkumar Hariram Chauhan^1,2, Ashish Kumar Jha^2,3, Pooja Dwivedi^1,2, Rutuja Dasharath Parab^2,3, Vishal Vajarkar^1,2, Archi Agarwal^1,2,3, Venkatesh Rangarajan^1,2,3

¹Department of Nuclear Medicine and Molecular Imaging, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, ²HBNI, ³Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Mumbai, Maharashtra, India

Introduction: Well counters are crucial non-imaging devices used for in-vitro studies and for the high-sensitivity counting of radioactive samples, such as those involved in blood or urine analysis (e.g., glomerular filtration rate (GFR) assessment by plasma sampling) and contamination detection (e.g., wipe testing). Ensuring the reproducibility and accuracy of these instruments requires routine quality control. This study aims to evaluate the stability, accuracy, and precision of four well counters through an analysis of their daily quality control data.

Materials and Methods: Four CAPRAC-t well counters (Capintec-INC), installed in 2024, were subjected to daily quality control tests using standard radioisotopic sources, Cs-137 and Eu-152. Tests for energy resolution and linearity were performed before clinical use, and the results were recorded electronically. One month’s worth of daily quality control data was analyzed statistically to assess the performance of the well counters. Accuracy was determined in relation to the first recorded observation, and precision was evaluated by calculating the coefficient of variation (CV).

Results: The mean energy resolution and standard deviation for the four well counters were 7.45 ± 0.18%, 7.24 ± 0.18%, 7.60 ± 0.20%, and 7.83 ± 0.23%. The accuracy values were 99.95%, 99.94%, 99.94%, and 99.95%, while the coefficients of variation were 0.23%, 0.22%, 0.22%, and 0.23% for the respective counters.

Conclusions and References: The results demonstrate that the performance of all four well counters remained stable, accurate, and highly precise over the study period. This consistency supports the effective use of these well counters for in-vitro studies and the high-sensitivity counting of radioactive samples, ensuring their reliability in clinical applications.

Abstract ID: 196: Reliability of radiochemical purity in different radiation detectors

Anubhav Enos Kumar, Julie Hepzibah

CMC, Vellore, Tamil Nadu, India

Introduction: It is essential to check the radiochemical purity (RCP) of the radiopharmaceutical before administering it into the patient. It is done after tagging a Tc99m eluate in the required kit and it is performed after 15 mins from the preparation time. This will help to ensure optimal scheduling of patients for the study. Radiation Detector is an instrument used to detect and measure ionizing radiation. Chromatography is an analytical method used to detect and determine the radiochemical impurities in each radiopharmaceutical.

Aim: To compare the RCP by paper chromatography with different radiation detector instruments.

Objective: To check the reliability of the different radiation detector instruments for chromatography QC.

Materials and Methods: Materials: Whattmann paper, Solvents (Acetone, Saline, Methanol).

Instruments:

1. Well Counter

2. Dose Calibrator

3. Contamination Monitor

4. Gamma Camera

5. Survey Meter

Methods: 54 data of paper chromatography values in 5 different instruments (Well Counter, Dose Calibrator, Gamma Camera, Contamination Monitor, Survey Meter) were collected for different radiopharmaceuticals (Tc99m MDP, Tc99m MIBI, Tc99m Nano Colloid).

Results: Well counter is the most reliable instrument for chromatography. Keeping Well counter values as the reference values, the instrument with least deviation -4.5 is Gamma Camera, whereas for Dose Calibrator it is -6.4, Contamination Monitor it is -7.4, Survey Meter it is -18.6.

Conclusions and References: Gamma Camera can be used for chromatography in the absence of a Well Counter.

Abstract ID: 8: Manual versus automated synthesis of Ga68-labelled radiopharmaceuticals – A comparison study

S. V. Ramanamurthy, K. Rajakumar, K. B. Sricharan

Homibhabha Cancer Hospital and Research Centre, Visakhapatnam, Andhra Pradesh, India

Introduction: In recent years the application of Ga68 labelled radiopharmaceuticals like PSMA (Prostate specific membrane antigen), DOTA-TOC (1, 4, 7, 10 –tetra azacyclododecane 1, 4, 7, 10 tetra acetic acid), FAPI (Fibroblast activation inhibitor) has increased for PET-CT in clinical practice. Ga68 is having suitable physical, chemical and radioactive decay properties and is basically produced from Ge68-Ga68 generator. Preparation of Ga68 labelled radiopharmaceuticals (RPs) are basically by manual, semi-automatic and fully automatic methods. Production by means of manual and semi-automatic methods can often lead to increased radiation dose to technologist, synthesis time and decreases production yield. The present study compares the Ga68 labeled radiopharmaceuticals utilizing fully automated synthesis module with manual method.

Aim: The aim of the present study was to compare the data of the production of Ga68 labelled RPs by manual and fully automatic synthesis methods.

Objective: Comparing the productive yield and radiation exposure in manual and fully automatic synthesis of Ga68 labelled RPs.

Materials and Methods: This study was conducted by using a 1.1 GBq (30 mCi) of Ge68-Ga68 generator procured from ITG, Germany and also fully automated module installed by COMECER, company.0.5 mg psma-11,1.0 mg DOTA-TOC peptides,1.0 mg FAPI, Radiosynthesis cassette set and reagent kits are obtained from ABx, Gmbh company, Germany. A survey meter cum contamination monitor was used to measure the radiation level at the radio pharmacy lab before start and during the labelling procedure and also the accuracy of surverymeter was evaluated periodically by measuring the exposure at 2 metres distance from the known activity of I-131. Even electronic pocket dosimeter was used to monitor the instant radiation exposure level during the synthesis and readings were noted.

Results: Data was collected for each 12 synthesis of different radiopharmaceuticals with Ga-68 by manual and fully automatic synthesis methods. The maximum radiation dose received during manual labelling method of Ga68-PSMA is 9 µSv, whereas 2 µSv in case of fully automatic method. The maximum radiation dose received during manual labelling method of Ga68-DOTA-TOC is 10 µSv whereas 2 µSv in case of fully automatic method. Nearly 20 minutes was taken for the final product in manual method but it took only 12 minutes with the automated method. Labeling yield for automatic (85%) was much superior than manual method (67%).

Conclusions and References: The main advantage of automatic synthesis module is reduced risk cross of contamination, high reliability, better reproducibility and time saving, reduction of radiation burden to technologist over the manual method. However, manual synthesis method has proven has cost effective over fully automatic synthesis method.

Abstract ID: 10: Estimation of airborne contamination during therapeutic radioiodine-131 (I-131) administration of capsules and solution form: A comparison study

S. V. Ramanamurthy, K. B. Sricharan, K. Rajakumar

Homibhabha Cancer Hospital and Research Centre, Visakhapatnam, Andhra Pradesh, India

Introduction: In Nuclear medicine radionuclide therapies 90% are performed using with I-131, because of its physical and radioactive properties. I-131 is available in solution and capsule form. The solution form of I-131 is having higher exposure risk, due to vaporization and spillage. One of the main requirements for radiation protection in Nuclear medicine is workplace monitoring. It helps to determine the personnel exposure to ionizing radiation and thereby controlling the intake airborne radioactive materials by workers. The optimal concentration of I-131 in air is defined by Derived Air concentration (DAC). According the radiation safety guidelines for airborne concentration of I-131 must be < 416.7 Bq/m3.

Aim: To compare the airborne contamination during the administration of capsule and solution form of I-131.

Objective: The objective of this study is to compare the airborne contamination by calculating DAC for all samples during dispensing and administration of I-131 by using capsule and solution form.

Materials and Methods: In this study air monitoring was performed using a portable air sampler with charcoal impregnated cellulose filters measure the I-131 contamination (air) by sample collection and analysis. Air samples were drawn during therapeutic dose dispensing and administration (50 mCi -200 mCi) at Hot lab in our hospital. Air sampler was placed at distance of 1 meter from patient. The flow rate was adjusted to 2.2 liters per minute and the sampler was allowed to run for 15 minutes. The measured airborne activity concentration is expressed as a fraction of the DAC limits for I-131.

Results: Data was collected during I-131 dose administration (50 mCi to 200 mCi) in total of 50 patients. The minimum airborne contamination while dealing with 50 mCi of I-131 in capsule form i.e. 8.33 Bq/m3 and maximum with 200 mCi of I131 solution form i.e. 77.40 Bq/m3.

Conclusions and References: Use of I-131 in capsule form limits the airborne contamination and spillage, thereby making radioactive waste management easier. Although the maximum values obtained in this study are 6 times and 11.6 times below the standardised DAC limits for solution and capsule forms respectively.

Abstract ID: 23: Ensuring regulatory compliance in establishing a commercial radiopharmaceutical facility

Dilshad Kottuparamban, R. Hridya Raj, Anees Muhammed, Raviteja Nanabala, K. N. Sudhakaran Nair, M. R. Ambikalmajan Pillai, Ajith Joy

Molecular Radionuclide Pharmacy Private Limited, Ernakulam, Kerala, India

Introduction: Reliable and consistent supplies of radiopharmaceuticals is essential for the growth of nuclear medicine in India. While the Department of Atomic Energy (DAE) has been doing a yeomen service in this regard, there is a gap in the availability of some of the critical radiopharmaceuticals especially iodine-131 used for treating thyroid cancer. A commercial radiopharmaceuticals facility has been set up complying with Atomic Energy Regulatory Board (AERB) regulations and Good Manufacturing Practices (GMP). The facility also incorporates the production of freeze-dried kits for the formulation of 99mTc radiopharmaceuticals. This paper outlines the strategies and measures undertaken during the setting up phase of the facility to meet regulatory requirements and ensure safety, quality, and environmental protection.

Materials and Methods: A strategic location was selected for the facility, with limited public access and favourable geographic conditions. The facility layout was designed to incorporate both radioactive labs and clean rooms dedicated to cold kit production. Facility’s expert team designed the hot cells that can be used for handling bulk imported activity of iodine-131. An in-cell automatic dispenser was selected which can make iodine-131 capsules and solution vials. Equipment procurement and installation were conducted with necessary quality control and assurance tests. Standard operating procedures were implemented, and training provided to the staff in radiation safety, best practices, and emergency response. Comprehensive safety analysis reports were submitted to AERB for approval of the facility. Also Type A package for transportation of the activity were developed and got type approved by AERB.

Results: Meticulous planning and implementation of regulatory compliance measures led to the successful establishment of the commercial radiopharmaceutical facility. Indigenous development of hot cells of international standard and Type A packages enhanced the operational convenience and radiation safety of the staff, public, and environment. The 75 mm lead shielded hot cells installed is licensed to handle up to 15 Ci of iodine -131 per batch. Similarly, 20 mm and 30 mm lead shielded Type A packages are authorized to transport iodine-131 activities up to 1.2 Ci and 4.3 Ci, respectively.

Conclusions and References: The facility significantly strengthens India’s radiopharmaceutical manufacturing capabilities, improving patient access to quality healthcare.

Abstract ID: 30: Design and analysis of MRL 30 Type-A package using finite element approach

Muhammed Anees, Dilshad Kottuparamban, K. N. Sudhakaran Nair, A. D. P. Rao

Molecular Cyclotrons Pvt. Ltd, Ernakulam, Kerala, India

Introduction: Effective and safe transport of radioactive materials requires suitable packaging formats that comply with safety regulations. This research focuses on the design and analysis of MRL 30-Type A Package, establishing its mechanical integrity in normal and special conditions of transport, stipulated by the Atomic Energy Regulatory Board (AERB). The structural analysis of the package was carried out using the ANSYS software based on Finite Element Method (FEM). This work aims at identifying potential failure modes and evaluating the factors of safety (FOS) under various loading conditions.

Materials and Methods: MRL30 –Type A package is designed for transportation of liquid radioactive material in glass vials in a lead shielded containment encased in Expanded Poly Ethylene foam and an outer stainless steel protective drum. A comprehensive 3D model of the Type A Package was developed using ANSYS software. The analysis simulated three distinct drop tests (corner, vertical, and horizontal drops from a height of 9 meters), two penetration tests (vertical and horizontal impacts from 1.7 meters), and a stacking test simulating a pressure of 13 kPa applied to the package stipulated in AERB code. Material properties were defined based on established standards to ensure realistic simulation outcomes.

Results: The stress analysis demonstrated that the deformations during the 9 m drop tests were limited to the outer protective drum without any damage to the inner shielded containment and the maximum permanent deformation of 15.17 mm in the worst case (corner drop) did not cause any loss in shielding. It also confirmed that during the drop and penetration tests the maximum induced stresses, the maximum elastic strains and factor of safeties are within limits and the package contents remained intact without shielding loss or spillage of its contents. The stacking test revealed a negligible deformation of 1.94 mm. Overall the analysis showed that the package is capable of withstanding the transport conditions.

Conclusions and References: The MRL 30 Type-A Package has been tested according to established safety codes and standards of AERB. The analysis demonstrated adequate structural integrity, particularly the inner shielded containment, which remained intact across all scenarios. While some deformation occurred in the outer steel drum during the drop tests, it did not compromise the overall structural and shielding integrity of the package.

Abstract ID: 62: Radiation safety protocols for paediatric patients in nuclear medicine

A. Jenifer Saranya, E. Venkatachalapathy, M. Palani, K. Sibu, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Paediatric patients are particularly sensitive to ionizing radiation due to their rapidly dividing cells and longer life expectancy, increasing the risk of radiation-induced harm. In nuclear medicine, where radiation is utilized for diagnostics and therapy, minimizing exposure is vital. This study investigates the effectiveness of radiation safety protocols designed specifically for paediatric patients, emphasizing the optimization of radiopharmaceutical doses, advanced imaging technologies, and adherence to the ALARA (As Low As Reasonably Achievable) principle.

Materials and Methods: Patient Selection and Grouping: The study included paediatric patients aged 0 to 16 years undergoing nuclear medicine imaging, categorized by age and weight for radiopharmaceutical dosing. Dose Optimization Protocols: Radiopharmaceutical doses were adjusted based on patient's weight, height, and clinical requirements to enhance safety. Application of Safety Measures: Safety measures, including time, distance, and shielding protocols, were implemented during all procedures. Techniques to prevent repeat scans, such as patient sedation and immobilization, were used to reduce motion artifacts. Assessment Tools: Dosimetry measurements were conducted pre- and post-protocol implementation to quantify radiation exposure. Image quality was assessed by experienced radiologists using established criteria.

Results: Dose Reduction: Optimized dosing protocols achieved an average radiation dose reduction of 30-50% depending on the imaging modality and weight, particularly benefiting younger and smaller patients. Image Quality: Despite reduced radiation doses, image quality remained intact, with no significant differences in diagnostic accuracy compared to standard protocols.

Reduced Repeat Scans: The use of immobilization and sedation technique led to a decrease in repeat scans due to movement-related artifacts.

Conclusions and References: Radiation safety protocols in paediatric nuclear medicine are essential for minimizing the risk of radiation exposure while ensuring accurate diagnostic and therapeutic results. Strategies such as dose optimization, advanced imaging technologies, and patient-specific safety measures effectively minimized risks. By adhering to these protocols, paediatric nuclear medicine can provide essential diagnostic information while protecting young patients from potential long-term radiation effects.

Abstract ID: 63: Radiation protection of pregnant worker and patient in nuclear medicine

Subrata Pathak, Pankaj Tandon

Atomic Energy Regulatory Board, Mumbai, Maharashtra, India

Introduction: The same radiation protection principles apply to both men and women, but additional measures are needed for pregnant women to protect the unborn child. Each year, thousands of pregnant women are exposed to ionizing radiation through work or medical procedures. Lack of knowledge of radiation risks can cause anxiety or lead to unnecessary pregnancy terminations. This article intend to provide verified information in condensed form for protection of pregnant worker and patient from ionizing radiation. This helps address misinformation from special interest groups and raises awareness about the extra care needed for pregnant women.

Materials and Methods: An in-depth literature survey was conducted, followed by a critical evaluation of peer-reviewed scientific articles and regulatory safety documents to prepare this article with evidence-based information.

Results: Once a female radiation worker confirms her pregnancy, her working conditions should be reviewed with the RSO to ensure the dose to the conceptus remains below 1 mGy, while minimizing the risk of high accidental doses and radionuclide intakes. The suggested restrictions do not require pregnant women to completely avoid radiation work or controlled areas; misunderstanding this could limit job opportunities for female radiation workers of childbearing age. Many patients mistakenly think exposure from a nuclear medicine exam begins at the scan and may not mention a potential pregnancy until after receiving radiopharmaceuticals (RPs). Therefore, women of reproductive age should be screened for pregnancy before administering RPs. Two major factors contribute to fetal radiation exposure: a) placental transfer and distribution of radiopharmaceuticals (RPs) in fetal tissues, and b) external irradiation from radioactivity in maternal tissues. Some RPs such as 131I as iodide and 32P as phosphate can rapidly cross the placenta. Therefore the possibility of pregnancy should be very carefully ascertained before such radionuclides are administered for therapy.

Conclusions and References: The human embryo and fetus are sensitive to ionizing radiation at doses above 100 mGy, which is five times the annual dose limit for radiation workers. Whereas, dose to the conceptus should be kept below 1 mGy as specified in regulation. The suggested restriction on pregnant worker do not require pregnant women to completely avoid radiation work. Exposure from diagnostic procedures and occupational radiation within regulatory limits is unlikely to harm the fetus. Therapeutic and high-dose diagnostic procedures involving the lower abdomen or pelvis in women of childbearing age may require careful radiation safety planning.

Abstract ID: 64: Radiation exposure management in emergency scenarios in nuclear medicine

M. Srivignesh, E. Venkatachalapathy, M. Palani, K. Sibu, G. Sakthivelayudham, V. Lokesh

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

Introduction: Nuclear medicine involves the use of radioactive materials for diagnostic and therapeutic purposes. While stringent safety protocols are in place, emergency scenarios—such as accidental radiation spills, equipment malfunctions, or patient contamination—can occur, posing risks to staff, patients, and the environment. Effective radiation exposure management in these scenarios is critical to minimize radiation hazards and ensure rapid recovery while maintaining safety standards.

Materials and Methods: Radiation exposure emergencies in nuclear medicine can be categorized into three primary types: radioactive spills, contaminated patients or staff, and equipment malfunctions leading to unintended radiation exposure. Preparedness requires a multidisciplinary approach, integrating radiation safety officers (RSOs), medical physicists, nuclear medicine technologists, and hospital safety teams. Standard operating procedures (SOPs) must be in place, including:

• ● Training and Drills: Regular training and emergency drills are crucial to ensure that staff can rapidly implement decontamination and exposure mitigation protocols.

• ● Radiation Monitoring: Real-time monitoring with personal dosimeters and portable radiation detectors enables prompt identification of exposure levels.

• ● Containment Measures: In the event of a spill, immediate containment through the use of lead shields, absorbent materials, and specialized protective equipment is essential. Evacuation protocols must be clear and efficient.

• ● Decontamination Procedures: For contaminated individuals or areas, specific decontamination protocols must be followed, including the use of appropriate cleaning agents and monitoring for residual contamination.

Results: Implementing a well-coordinated response plan in radiation emergencies can significantly reduce both immediate and long-term exposure risks. Successful case studies have shown that early detection, swift containment, and proper decontamination procedures can lower occupational and environmental radiation risks by up to 70%.

Conclusions and References: Emergency preparedness in nuclear medicine is paramount to managing unexpected radiation exposure scenarios effectively. Comprehensive training, clear communication, and access to adequate safety tools are essential to protecting personnel, patients, and the public. Continuous evaluation and updating of safety protocols can further enhance the management of radiation exposure in emergency scenarios, ensuring a safe clinical environment.

Abstract ID: 85: Use of teledetectors in the practice of radiation safety

Jai Surya, Tirzah, Prabu Titus Devakumar, Julie Hephzibah, Saumya Sara Sunny, Junita Rachel John

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Radionuclide therapy is a specialized nuclear medicine treatment that uses radioactive isotopes, such as Iodine-131 and Lutetium-177, to target and destroy cancer cells through gamma and beta radiation. This therapy offers localized treatment, improving patient outcomes. After receiving I-131 for thyroid carcinoma, patients are typically isolated for 2 days due to radiation risks. Surveys are conducted 1 hour and 24 hours post-treatment using the Ranger instrument to measure radiation exposure at the surface and 1 meter from the patient. Discharge is allowed if exposure levels are below 50 µSv/hr. This study investigates the impact of using a Teledetector to reduce radiation exposure for personnel during these surveys compared to standard methods.

Objective: The primary aim of this study is to know the effect of using a Teledetector in minimizing radiation exposure to the technologist during patient surveys following radionuclide therapy.

Materials and Methods: Using a Teledetector (a selfie stick securing the survey meter-Ranger) can increase the distance to enhance radiation safety. Radiation surveys were taken from 15 patients using both the Standard method and the Teledetector method at 1 hour and 24 hours after therapy. The exposure rates in both methods were recorded and compared.

Results: The results indicated that exposure levels decreased as the distance increased, significantly reducing the radiation exposure to the technologist during surveys.

Conclusions and References: The use of Teledetector significantly reduces the radiation dose received by technologists during patient surveys by half. This method is especially advantageous in nuclear medicine departments that have multiple isolation wards and a high volume of therapy procedures, as well as in areas with elevated contamination levels, and radioactive waste disposal.

Abstract ID: 95: Personal radiation exposure in robotic-arm assisted FDG PET/CT guided biopsy

Vrati Jain, Geetanjali Arora, Apoorva Tyagi, Bhabani Shankar Nayak, Sivasankar Kanankulam Velliangiri, Madhavi Tripathi, Bibekanad Arya,C. S. Bal

All India Institute of Medical Sciences, Delhi, India

Introduction: Positron emission tomography (PET/CT) - guided biopsy plays an important role in tissue diagnosis when the target lesion is undefined or indeterminate on conventional imaging modalities especially in the presence of necrosis which may result in inconclusive or false-negative histopathological results. However, PET/CT-guided biopsy results in radiation exposure to the physicians and staff performing the procedure which must be kept as low as possible according to ALARA principle. The main aim of our study was to find the personnel radiation exposure to physicians and technologists during robotic arm-assisted F-18 Fluorodeoxyglucose (FDG) PET/CT guided biopsy and to assess its relationship with procedure time.

Materials and Methods: This was a prospective study done at a tertiary care hospital. Institutional ethics committee approval was taken along with written and informed consent. Patients referred for FDG PET guided biopsy from January to August 2024 were included. Each patient was scheduled as first patient, FDG injected intravenously and patient was taken-up for biopsy. Then a limited field of view PET/CT was acquired depending on the target lesion followed by image transfer to the robotic-arm console for trajectory planning. Entry and target point was defined and the needle inserted with robotic arm guidance. All persons (Physician and technologist) were provided with pocket dosimeters before the start of the procedure and individual radiation exposure was measured at the end of the procedure.

Results: A total of 20 patients were included in our study. The mean age was 47.8±19.9 years with 11 males and 9 females. The site of biopsy was the thorax in 10 patients and the abdomen & pelvis in 10 patients. The median injected activity was 3.7±1.9 mCi. The mean uptake time post-FDG injection was 37.1±18.4 minutes. The median procedure time was 37.1±18.4 minutes. The mean radiation dose for physician and technologist were 7.3 ±5.4 µSv and 1.4 µSv±1.2 µSv respectively. There was no significant correlation between uptake time and radiation exposure for physicians and technologists. We found a significant correlation between procedure time and radiation exposure to physicians.

Conclusions and References: The procedure time must be kept as low as possible to reduce radiation exposure for the performing physician. By implementing this ALARA principal FDG PET guided biopsies targeting metabolically active lesions performed by robotic arm assisted needle positioning is technically feasible, safe, and effective.

Abstract ID: 135: Radioprotective peelable surface decontamination agents: Innovative approach towards radiation emergency preparedness and response management

Bhushan Shivanand, Maddassani Srinivasulu, Sibi Oommen, Sumeet Suresh Malapure

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

Introduction: Utilizing metallic nanoparticles such as lead, tungsten, or bismuth oxide within epoxy-based nanocomposites presents a promising avenue for reducing radiation exposure in biomedical radioisotope laboratories. These materials offer effective attenuation of radiation, safeguarding both operators and the public. Furthermore, employing suitable polymers, resins facilitates the removal of radiochemical contamination without compromising surface integrity.

Materials and Methods: Study entails the development of novel processes for fabricating lead, bismuth tungsten oxides nanoparticles of varying sizes and shapes alongside the synthesis of Polymers, ligands and chelates capable of complexing with radioactive materials with optimal curing time to get peeled off smoothly. Through optimization, ideal thickness applying of these nanocomposites has to maximize radiation shielding. Current decontamination methods, such as surface wiping or replacing contaminated materials are conventional but often not effective insufficient & exhaustive work.

Results: Our approach aims to revolutionize decontamination by introducing an indigenous surfactant system that forms strong complexes with radioactive materials to decontaminate as well as embedded within nanocomposites to shield radiation effectively.

Conclusions and References: By optimizing composition and thickness, we strive to provide cost- effective solutions for Spill-contamination management, significantly improving safety protocols in biomedical facilities to get ready to handle radiation emergency & risk reduction smartly.

Abstract ID: 156: Occupational radiation exposure in stand-alone medical cyclotron facilities: A detailed analysis across operational roles

Gurkirat Singh Nizer

Curium Pharma (India) Private Limited, Noida, Uttar Pradesh, India

Introduction: Stand-alone medical cyclotron facilities are central to the production of PET radiopharmaceuticals but pose distinct radiation exposure risks to staff across multiple operational roles. This study quantifies occupational exposure among cyclotron operators/engineers, radiochemists/radio pharmacists/QC personnel, and auxiliary staff (including dose handlers and drivers), identifying high-exposure tasks to enhance radiation safety practices. To quantify and analyze occupational radiation exposure among different personnel roles at a stand-alone medical cyclotron facility, identifying high-risk tasks to guide safety enhancements.

Materials and Methods: A retrospective review was conducted on radiation dose records collected from January 2023 to August 2024 at a stand-alone cyclotron facility. The personnel, totaling 21 staff members, were grouped into cyclotron operators/engineers (n=5), radiochemists/radio pharmacists/QC (n=4), and auxiliary staff including dose handlers and drivers (n=12). Monthly personal dosimeter readings were analyzed, focusing on task-specific exposures (target handling, synthesis, QC, vial dispensing, dose transport) and compliance with ICRP and AERB limits.

Results: Cyclotron Operators/Engineers: Cyclotron operators recorded the highest annual dose, with an average of 16.2 mSv and a range of 14.8 to 19.5 mSv, primarily from direct target handling and cyclotron maintenance. Peak exposures reached 2.7 mSv during target unloading and hot-cell maintenance tasks. Radiochemists/Radio pharmacists/QC Staff: These personnel had a mean annual dose of 10.1 mSv, with a range of 8.2 to 12.9 mSv. High-exposure tasks included radiopharmaceutical synthesis and QC procedures, with vial dispensing exposing individuals to up to 2.4 mSv per event. Auxiliary Staff (Dose Handlers and Drivers): Auxiliary staff involved in dose handling showed lower exposure, with an average of 4.3 mSv annually (range: 2.5 - 5.8 mSv). Drivers had a consistently low cumulative exposure but with routine transport adding to their annual dose. Approximately 12% of all tasks, primarily for operators and radio pharmacists, involved doses exceeding 1.5 mSv, necessitating further safety controls. Dose transport tasks, although individually low, contributed to cumulative exposure risks for drivers over time.

Conclusions and References: Radiation exposure levels in this stand-alone cyclotron facility generally align with regulatory limits; however, operators and radiochemists face the highest occupational doses due to proximity to high-activity processes. Protective measures such as remote handling tools, automated vial dispensing, and procedural revisions for high-activity tasks are recommended. Regular monitoring and periodic safety protocol reviews are essential to maintain low cumulative exposure, particularly for dose handlers and transport personnel.

Abstract ID: 159: Evaluation of occupational radiation exposure by using pocket dosimeter in a tertiary care nuclear medicine department

B. Renganayaki, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: Aim of the study is to evaluate the Radiation Exposure during Patient Positioning in Nuclear Medicine Using Pocket Dosimeters: Compliance with Safety Standards. The assessment of radiation exposure during patient positioning in 18F- FDG (PET- CT) acquisition is crucial for ensuring compliance with safety standards and minimizing health risks to healthcare workers. This study aims to evaluate the levels of radiation exposure experienced by technologists during the positioning of patients undergoing nuclear medicine procedures, utilizing pocket dosimeters to measure exposure in real-time.

Materials and Methods: This study involved daily measurements of radiation exposure over a ten-day period, where 20 patients (approximately 2-4 mins) were positioned for PET-CT imaging. Pocket dosimeters were employed to quantify radiation exposure, with particular attention given to the time elapsed since radiopharmaceutical injection. The average exposure rate was recorded for each patient during positioning instantly. The distance between pocket dosimeter and the patient was approximately 90 cms in all the patients.

Results: The findings indicated an average radiation exposure of 30 µSv per day during patient positioning for 20 patients, which remained significantly below the daily limit of 66 µSv established by the Atomic Energy Regulatory Board (AERB). Notably, it was observed, at the time of acquisition radiation exposure levels were consistently within safe limits.

Conclusions and References: The study concludes that radiation exposure during patient positioning in nuclear medicine is well within acceptable safety standards, particularly when procedures are conducted with appropriate timing following radiopharmaceutical administration. Continuous monitoring using pocket dosimeters is recommended to ensure ongoing compliance and safety in nuclear medicine practices.

Abstract ID: 168: A cost effective and easy method to reduce radiation exposure to staffs while 18F-FDG dispensation

V. S. Rupan Kumar, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of the study is to test the technique that significantly reduces radiation exposure to professionals involved in the dispensing of 18F-FDG from multi dose vials. Traditionally, a lead pot is utilized to decrease radiation exposure during the dose dispensation process; however, this study introduces an innovative model that further enhances radiation safety.

Materials and Methods: A multi dose vial was placed in the lead pot, lumbar puncture needle was inserted in the dose vial and a 3 way lock was attached to the hub of lumbar needle, followed by placing a lead enclosure on top of the lead pot containing the activity vial. A dose of 10 mCi was withdrawn into a syringe and placed on top of 3 way lock. The exposure from the syringe is measured with and without the lead enclosure on the surface of L bench at multiple points. The exposure received was measured using well calibrated survey meter.

Results: By integrating a 3- way lock into the lumbar puncture needle and enclosing the setup with a 30 mm thick lead enclosure, the exposure received during dose withdrawal got minimized by at least 50%. Average exposure rate without lead enclosure (10 meaurements). Average exposure rate with lead enclosure (10 measurements) 6.2 µSv/hr, average exposure with lead enclosure (10 measurements) 2.88 µSv /hr.

Conclusions and References: The results support the application of this method in clinical practice instead of using automatic 18F-FDG injectors which are quite expensive. Application of this technique fosters a safer workplace for radiation professionals in accordance with the ALARA principle.

Abstract ID: 198: The role of the gamma camera in measuring I-131 liquid waste for high-dose therapy patient disposal: An alternative to the well counter

Aishwarya Thalapathy, R. Krishnakumar

Cancer Institute, Chennai, Tamil Nadu, India

Introduction: This study aims to evaluate the accuracy of different measuring devices, including gamma cameras and well counters, for assessing I-131 waste samples.

Materials and Methods: Material: Delay tank samples. Methods: I-131 waste samples were measured using a gamma camera, uptake probe, well counter, contamination monitor, and gamma probe. Comparisons were made to determine the accuracy and reliability of each device.

Results: Results indicate that while the well counter provided the most precise measurements, the gamma camera demonstrated comparable efficacy, making it a viable alternative in clinical settings.

Conclusions and References: The findings suggest that gamma cameras can serve as an effective, alternative tool for measuring I-131 waste in settings where well counters are unavailable, aiding in safer, more efficient waste management.

Abstract ID: 200: Reducing radiation exposure during Tc-99m MDP bone scan injection using lead brick barrier

K. P. Fathima, Julie Hephzibah, Adersh, Saumya, Hanna, Prabhu Titus

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: To evaluate the effectiveness of radiation protection offered by lead bricks barrier to the occupational worker while administering intravenous Tc-99m MDP injection to the patient.

Materials and Methods: lead bricks were stacked vertically on the injection table. The radiation worker stood behind the lead brick stack during the injection of 10-20 mCi of Tc99m MDP. Radiation exposure was measured using Geiger Muller survey meter in front and behind the lead brick barrier.

Comparative analysis was made between:

1. Conventional workflow: without lead brick

2. with lead bricks

Radiation exposure in front and behind the lead brick barrier was recorded and compared.

Results: Eight readings were compiled. the range was from 220 to 345 mSv/hr without lead bricks and it reduced to 2.6 to 6.8 mSv/hr with lead bricks.

Conclusions and References: Lead bricks barrier significantly reduced radiation exposure to the occupational worker during the administration of Tc99m MDP for bone scintigraphy. This can be implemented in daily work practice to enhance radiation safety.

Abstract ID: 204: Reducing exposure while administering I131 with lead and plastic apron

Sereena Angel Deta, Julie Hepzibah, Saumya, Prabhu Titus

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Radiation safety is of paramount importance in Nuclear Medicine where Radioactive isotopes, such as Iodine-131 (I-131) are used for both diagnostic imaging and therapy for conditions such as Hyperthyroidism and Carcinoma thyroid. Limiting the exposure during the administering of I-131 is crucial to ensure the health and safety of personnel involved. By implementing proper techniques and protocols we can effectively minimize the exposure risk. In general, this is achieved by decreasing the time spent, increasing distance from the radioactive source and proper use of shielding material and personal protective equipment. Materials like Lead attenuate gamma radiation and should not be used in isolation for beta particles as it can produce secondary radiation (bremsstrahlung). Thus, for I-131 use of a combination of material (lead followed by plastic) will stop the beta particles and then shield against gamma emissions.

Aim: To study the effectiveness of using a lead and plastic apron and plastic apron in isolation while administering high dose I131 to minimize radiation personnel radiation exposure.

Materials and Methods: High dose (100 mCi I-131) radioactive iodine therapy was administered by a Nuclear Medicine technologist and radiation exposure were compared using three different interventions in addition to standard radiation safety protocol. A pocket dosimeter was used to measure the radiation exposure while handling I-131. The interventions involved measuring the radiation exposure, first without plastic and lead apron, second with a plastic apron in isolation, and third with both lead and plastic apron, following which the exposure was compared in all three.

Results: The average radiation measured was Time spent in administering I131 was an average of 3 mins. With a distance of 1 m from the dose. The dosimeter showed the highest exposure without the lead apron.

Conclusions and references : Conclusion: This study confirms that it is justifiable to use lead aprons in combination with plastic apron while administering radioactive iodine. Radiation exposure while administering I-131 can be effectively decreased by this simple intervention of using a combination of lead and plastic aprons. This can be implemented into daily work practice to ensure adequate Radiation safety.

Abstract ID: 5: Preparation and pre-clinical evaluation of 64Cu-labeled bisphosphonate amide of DOTA for use in PET-imaging agent for bone metastases

Priyalata Shetty, K. V. Vimalnath, Sutapa Rakhit, Avik Chakraborty, Rubel Chakravarty, Sudipta Chakraborty

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: Bone metastases have high prevalence in advanced stage malignancies particularly in breast and prostate cancers and can gravely impact the prognosis as well as treatment outcomes. Hence, early and precise diagnosis of metastatic lesions is imperative for staging as well as in formulating appropriate treatment options. The use of radiolabeled bisphosphonates based on 99mTc and 68Ga in the diagnosis of skeletal metastasis have been well documented. The objective of the work reported herein is to formulate 64Cu-labeled bisphosphonate amide of DOTA (BPAMD) using reactor produced low specific activity 64Cu and study the potential utility of as a cost-effective, cyclotron independent alternative for PET imaging of bone metastases.

Materials and Methods: Copper-64 was produced by neutron irradiation on natural CuO target (>99.99% chemical purity) at Dhruva research reactor at 1.2×1014 n/cm2.s thermal neutron flux for 3 days. Irradiated target was converted to [64Cu] CuCl2 solution after dissolution ultrapure HCl. Radiolabeling protocol of BPAMD (ABX Advanced Biochemical Compounds, Germany) with 64Cu was optimized by varying different reaction parameters such as pH, ligand concentration, reaction time and temperature. The in vitro stability of the formulation was monitored in physiological saline and human serum at 37⁰ C up to 48 h post-preparation by radio-TLC. In vitro hydroxyapatite (HA) uptake studies to determine bone specificity were performed using synthetic HA microparticles and the in vivo biodistribution pattern of the formulation was determined in healthy Wistar rats using by PET imaging.

Results: Under optimized radiolabeling conditions, [64Cu]Cu-BPAMD was obtained with 98.2 ± 0.4% radiochemical purity (as determined by radio-TLC) using 1 mg of BPAMD and 370 MBq [64Cu]CuCl2 post 30 min incubation at 100⁰ C. The formulation retained >97% radiochemical purity post 48 h both in physiological saline and human serum, whereas HA binding study showed >95% uptake. The results of PET imaging study in normal Wistar rats the revealed significant bone uptake with good excellent target to non-target contrast.

Conclusions and References: In the present study, we have demonstrated an optimized protocol for the formulation of [64Cu] Cu-BPAMD using reactor produced low specific activity 64Cu for non-invasive imaging of bone metastases. The formulation was prepared with high radiochemical yield as well as excellent stability and showed good uptake in preclinical settings. The approach of using low specific activity 64Cu in the development of the radiolabeled BPAMD complex presents a cost-effective alternative to 68Ga/18F based agents.

Abstract ID: 6: 166Dy/166Ho-labeled hydroxyapatite microparticles for use in the treatment of inflammatory joint diseases – Demonstrating the utility of in vivo radionuclide generator

Sourav Patra, Khajan Singh, Shahiralam Khan Mohammed, Avik Chakraborty, Sudipta Chakraborty

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: Holmium-166 [T½ = 26.8 h, Eβ= 1.74 MeV (48.7 %) and 1.85 MeV(50.0%), E(gamma) = 80.6 keV] is one of the preferred radionuclide in radiosynovectomy (RSV) for treatment of inflammatory joint diseases. However, short half-life of 166Ho is a major practical impediment. The object of the present work is to overcome this problem by using 166Ho produced from the □- decay of 166Dy [T½ = 81.5 h], which exists in transient equilibrium with 166Ho. We have developed 166Dy/166Ho-Labeled nanoporus hydroxyapatite (nHA) microparticle formulation such that its localized intra-articular administration would prolong the irradiation of the diseased joint with the beta emission from 166Ho following the half-life of 166Dy.

Materials and Methods: The nHA microparticles were synthesized by wet chemical method followed by spray drying using calcium carbonate and disodium hydrogen phosphate as precursor of Ca and P respectively (Ca/P=1.67). Equilibrium mixture of 166Dy/166Ho was produced by neutron irradiation of natural Dy2O3 in Dhruva reactor at flux 1.2×1014 n/cm2/s for 14 d. The irradiated target was dissolved in 0.1 M HCl (ultrapur®). Subsequently, a one-step radiolabeling protocol was optimized to formulate 166Dy/166Ho-nHA with high radiochemical purity. For biological evaluation, the formulation was administered to the ankle joint of healthy Wistar rats intra-articularly and SPECT/CT images were recorded at different time intervals.

Results: Nanoporous HA microparticles were synthesized in 1-10 μm size range and with 1.4 ± 0.2 nm pore diameter. The synthesized microparticles exhibited high sorption capacity (270 ± 6 mg Dy/g) for Dy with > 99% radiolabeling yield for 166Dy/166Ho. Sorption of 166Dy/166Ho in nHA followed Langmuir-Freundlich adsorption isotherm and pseudo second order kinetics, indicating that radiolabeling process was chemisorption. Almost no leaching of either 166Dy or its daughter product 166Ho from the radiolabeled particulates could be observed in physiological saline upto 14 days from the time of formulation. SPECT/CT images showed that the administered 166Dy/166Ho-nHA formulation was completely retained within the knee joint cavity even after 96 h of post administration and there is no uptake of activity in any other organ.

Conclusions and References: In conclusion, we have synthesised porous, biocompatible, nHA and radiolabled with 166Dy/166Ho to develop 166Dy/166Ho–nHA in vivo generator system that could generate a new avenue for the treatment inflamed joint diseases by radiosynovectomy.

Abstract ID: 14: Validation of in house automated synthesis of 68Ga-PDL1 and its quality control for routine production

Jay Prakash Kumar^1,2, Manoj Chauhan^1,2, Arvind Suresh^1,2, Bhola Kumar^1,2, Ritwik Sinha^1,2, Uddeshya Narayan Jha^1,2, Yash Jain^1,2, Varun Shukla^2,3

¹Department of Nuclear Medicine, Mahamana Pandit Madan Mohan Malaviya Cancer Centre (A unit of Tata Memorial Centre), Varanasi, Uttar Pradesh, ²Homi Bhabha National Institute, Mumbai, Maharashtra, ³Homi Bhabha Cancer Hospital and Research Centre, New Chandigarh, Punjab, India

Introduction: In recent years, immunotherapy has been emerging as a promising alternative therapeutic method for cancer patients, offering potential benefits. The expression of PD-L1 by tumors can inhibit the T-cell response to the tumor and allow the tumor to evade immune surveillance PDL1 PET/CT is a non-invasive imaging investigation which can give a novel insight into the PDL1 expression of the whole body tumor burden. Limitation of tissue Biopsy is that, it gives PDL1 expression of only that site, which may or may not be representative of the whole body tumor burden. The aim of the study was to label PDL1 with 68Ga with in automated synthesizer module.

Materials and Methods: 68Ga -PDL1 was synthesized by adding the amount of PDL1 (15-30 μg) to full volume (4-5 mL) 68Ga in 0.05 M HCl in automated synthesizer IQS-TS module. The reaction mixture was heated at 95°C for 7 min at pH 3.5-4 to obtain the radiotracer with high radiochemical purity (RCP) and high yield. Quality control procedures were done to assess the RCP, stability of the radiotracer. Radiochemical purity of final product was quantitively analysed by instant thin layer chromatography on TLC Scanner and high performance liquid chromatography (HPLC).

Results: 0.4 mCi of 68Ga/μg of PDL1 at 95°C for 7 min was the optimal parameter to obtain 80%-82% of yield and average radiochemical purity of the product was > 95%. The retention time of the 68Ga -PDL1 is between 11 and 12 min. Intense radiotracer uptake was noticed in the tumor and no uptake was noticed in healthy tissues.

Conclusions and References: The fully automatic and simplified synthesis of 68GaPDL1 was obtained on cassette-based module with high radiochemical purity. Potential applications include better patient selection and performing PDL1 PET/CT pre and post PDL1 inhibitor therapy to predict response.

Abstract ID: 20: Integrating background processes in radiopharmaceutical precursor synthesis for PET and SPECT applications

K. S. Ali Muhammad, Jaise Mariya George, Raviteja Nanabal, M. R. A. Pillai

Molceular Radionuclidepharmacy Pvt. Ltd, Kochi, Kerala, India

Introduction: In-house synthesis of radiopharmaceutical precursor is essential for ensuring a reliable and uninterrupted supply, minimizing dependence on external suppliers and enhancing quality control. This study aimed to develop efficient and cost-effective methods for synthesizing precursors, including Mebrofenin (Bromo-HIDA) L, L-EC, and Mannose triflate, for radiopharmaceutical applications.

Materials and Methods: Three key precursors were synthesized, Mebrofenin was prepared by condensing 3-Bromo-2, 4, 6-trimethylaniline with nitrilotriacetic acid using acetic anhydride and pyridine as solvent. L, L-EC was synthesized through the dimerization of 4-L-thiazolidine carboxylic acid using sodium metal in liquid ammonia. Mannose triflate was prepared by reacting 1, 3, 4, 6-tetra-o-acetyl-beta-d-mannopyranose with trifluoromethane sulfonic anhydride (O (SO2CF3)2) under an inert atmosphere using dichloromethane as solvent. Thin layer Chromatography used to identify the formation of final product by disappearance of starting material in the reaction mixture. Synthesized compounds were characterized using IR, NMR, and mass spectroscopy.

Results: By TLC Analysis the starting material spot disappeared in reaction mixture conforming the formation the desired products. FT-IR, ¹H, and ¹³C NMR spectra confirmed the structure of Mebrofenin (melting point: 205oC). ¹H, ¹⁹F NMR (-74 ppm prox.) and mass spectral analysis confirmed the structure of Mannose triflate (melting point: 118 – 120oC). Characteristic IR spectra confirmed the structure of L, L-EC (melting point: 225-232 oC). The analytical results were consistent with literature values. Yield for all the reaction are comparable to literature.

Conclusions and References: Successful scaling of the reactions from milligram to gram quantities significantly increased production capacity. Four batches of Mebrofenin, six batches of L, L-EC, and five batches of Mannose triflate were produced, demonstrating the feasibility of in-house synthesis for meeting the demands of radiopharmaceutical production.

Abstract ID: 21: Setting up a GMP based I-131 dispensing facility and optimizing the formulation of I-131 solution and capsules for oral administration

Raviteja Nanabala, Jaise Mariya George, Raviteja Nanabala, Dilshad Kottuparamban, R. Hridya Raj, Anjana Gopal, Ashna K. Babu, K. N. S. Nair, M. R. A. Pillai

Molecular Radionuclide Pharmacy Pvt. Ltd, Ernakulam, Kerala, India

Introduction: Iodine-131 is widely used for the diagnosis and treatment of thyroid cancer. It is supplied either in capsule or liquid form for oral administration. Due to the shortage of local production, 131I is imported by nuclear medicine departments in smaller qualities hence a large number of consignments are imported. A better alternative is to import bulk quantity of 131I and make the solution and capsules locally. Two key aspects of establishing such facilities are, adhering to AERB regulations and standardizing protocols for 131I formulation and quality control according to the Indian Pharmacopoeia. This paper focuses on optimizing 131I solution and capsule formulations using fully automated dispenser.

Materials and Methods: Indigenously designed and manufactured hot cells from Samrudhi, Mumbai, are installed at our facility with a lead thickness of 75 mm, consisting of two chambers (the chamber 1 is for receiving 131I mother vial and despatch of the product, while the automated dispensing system from Elex, Serbia, is housed in the second chamber) and a preparation glove box. For the solution formulation, 10-4 M NaOH solution with pH 10 is used to dilute the 131I mother solution already having 10% sodium thiosulphate, which can be dispensed into vials. For capsule formulation, capsule body is filled with an adsorbent (disodium hydrogen phosphate). Various particle sizes of adsorbents and solution volumes were tested for capsule preparation. All chemicals and reagents used were of pharmaceutical grade.

Results: All studies were done with simulated solution only. Standardization allowed us to dispense 131I solution in volumes ranging from 10 μL to 10 mL into vials. For capsule preparation, we observed that an adsorbent particle size of 150 to 300 microns was optimal for filling capsules with 131I solution without damaging the capsule, using solution volumes between 10 µL and 50 µL. Maintaining a pH of 10, using sodium hydroxide, prevents the volatility of 131I, while sodium thiosulphate acts as a reducing agent to inhibit radiolytic oxidation. While these optimizations were performed without radioactivity, the results can be applied to production using 131I stock solution.

Conclusions and References: Standard operating procedures were established. The facility is awaiting the receipt of 131I. Both I-131 solution and capsules can be produced at our facility as per GMP and quality-control can be performed according to the Indian Pharmacopoeia, ensuring high-quality standards that will benefit cancer patients.

Abstract ID: 40: Radiosynthesis of [68Ga] Ga-PSMA-11 using cyclotron produced 68Ga

Yuva Raj Nitin, Amit Kumar, B. K. Sharma, Shrinibas Nayak, Nawab Singh Baghel

Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: [68Ga] Ga-PSMA-11 is the first 68Ga radiopharmaceutical approved by US FDA for the imaging of Prostate specific membrane antigen (PSMA) positive prostate cancer. 68Ga is obtained through imported 68Ge/68Ga radionuclide generator. However apart from import, the 68Ge/68Ga radionuclide generator are inherently associated with certain limitations like, limited radioactivity, limited lifetime due to decay of the 68Ge, decreasing radioactivity per elution with time etc. Alternatively, sufficient amount of 68Ga can be produced directly in a medical cyclotron using 68Zn as target using 68Zn (p n)68Ga nuclear reaction route. Our aim is to synthesize [68Ga] Ga-PSMA-11 using cyclotron produced 68Ga.

Materials and Methods: 70 mg per mL of 68Zn was used to make 68Zn (NO3)2 solution in 0.2 M HNO3 and was irradiated in GE PET TRACE Cyclotron using indigenously fabricated niobium target. The proton beam energy was degraded using suitable thickness of Niobium foils to reduce the production of 67Ga. 68Ga was separated from 68Zn as [68Ga] GaCl3 using binary column solid phase extraction cartridges in our indigenously developed radiosynthesis module. Extracted 68GaCl3 was used to label HBED-CC-PSMA-11.

Results: 50 mCi of 68Ga was produced when 2.5 mL of 68Zn (NO3)2 solution was irradiated with 25 µA proton beam for 30 minutes. 68Ga produced in cyclotron was analyzed for concomitant production of 66/67Ga radionuclide impurities. The level of radionuclide impurities were found to be within the limit as per the European Pharmacopeia. The produced 68GaCl3 was used to label HBED-CC-PSMA-11 and the yields were more than 80% (decay uncorrected) with RCP greater than 99%. [68Ga] Ga-PSMA-11 passed all the QC parameters like PH, RCP, RNP, sterility and BET tests.

Conclusions and References: Cyclotron can be used to directly produce sufficient amount of 68Ga, which can be used to label peptides such PSMA-11 to produce [68Ga] Ga-PSMA-11 for routine PET imaging. This method of producing 68Ga can be a good alternative to imported 68Ge/68Ga generator.

Abstract ID: 41: Automated production of 177Lu DOTA peptides using a low cost in-house developed automated synthesis module using off-the-shelf components

Yuva Raj Nitin, K. R. Athulya, Neenu Thampi, Ashok Chandak, Nawab Singh Baghel

Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: 177Lu-DOTA-TATE is a therapeutic radiopharmaceutical used in treating neuroendocrine tumors. To minimize radiation exposure to personnel, this study presents an quickly assembled automated synthesis module for the final preparation of the radiopharmaceutical, ensuring compliance with current Good Manufacturing Practices.

Materials and Methods: a) Hardware and software: This advanced module integrates chemically inert 3/2-way solenoid valves, silicon-tubed peristaltic pumps, heater cartridges for precise heating, an NTC thermistor for accurate temperature sensing, a GM radiation detector for activity measurement in the column, and transfer tubing—carefully designed to streamline radiopharmacy workflows. The software, programmed on an Arduino microcontroller, utilizes VNI8200XP based X-Nucleo-PLC01A1 boards, LM2596 buck converters for peristaltic pump speed control, ensuring precise control over fluid dynamics, heating, and real-time monitoring, resulting in exceptional operational efficiency. The Human-Machine Interface (HMI), developed in Visual Basic Studio, provides accessible control and real-time oversight of critical reaction parameters, including radioactivity and temperature. b) Method: The synthesis process begins with transferring 177Lu-Chloride to a reaction vial containing 2M ammonium acetate buffer and DOTATATE using a peristaltic pump. The reaction mixture is incubated at 95°C for 45 minutes. After incubation, the mixture is cooled with ultrapure water and loaded onto a preconditioned tC18 column, followed by a wash with 2 ml of saline. The 177Lu-DOTATATE is then eluted with 50% ethanol, followed by saline. The final product is passed through a 0.22-micron filter and pre-dispensed with 2,5-dihydroxybenzoic acid in saline.

Results: The automated synthesis module has successfully completed the test, demonstrating optimal performance and reliability.

Conclusions and References: These results demonstrated the module’s effectiveness for large-scale production, enhancing operational efficiency while significantly reducing radiation exposure to personnel. Its modular, scalable design employs readily available off-the-shelf components, offering a cost-effective, high-performance solution that optimizes efficiency, maintains rigorous quality control, and reduces radiation exposure, making it an invaluable asset for radiopharmacy applications.

Abstract ID: 45: Preparation of 177Lu-RGD dimer using indigenously designed automated synthesis module at RMC

M. K. Ray, Neenu Thampi, K. R. Athulya, S. Roshna, Yuvaraj Nitin, Ashok R. Chand

RMC, BARC, Mumbai, Maharashtra, India

Introduction: Peptide receptor radionuclide therapy (PRRT), which is a therapeutic procedure by radiopharmaceuticals labeled with beta emitter (177Lu), has received great interest due to its clinical impact. The utility of 177Lu is continually evolving, well imbedded in the field of targeted radionuclide therapy, and has unveiled a broad spectrum of 177Lu labeled therapeutic radiopharmaceuticals for treating a wide range of diseases (NET, prostate). The aim of the present study was to evaluate automated module designed the for the synthesis of 177Lu-based therapeutic radiopharmaceuticals as per cGMP guidelines to handle higher quantity of 177Lu activity and reproducible end product quality.

Materials and Methods: Automated module has been designed and program software for synthesis of 177Lu-based radiopharmaceuticals was furnished at RMC. DOTA-RGD dimer for the labeling was procured from ABX, GmbH. The first step was to sanitize the module using 70 % v/v ethanol and then fill the chemicals in to the respective vials to start the synthesis program. The module will take desired quantity of 177Lu activity (35-60 mCi) in to the reaction vial in which buffer and DOTA-RGD (1:2.5 of 177Lu: peptide) is already present and set the temperature at 950C for 45 min. The mixture was then cooled with water and load in to the activated C18 cartridge. The product collected in to sterile vial through 0.22 µm membrane filter with 1-1.5 ml of 50 % aqueous ethanol and dilute the product suitably with gentisic acid (stabilizer) dissolved in saline. All physicochemical evaluations carried out on the final product.

Results: The module was user friendly and steps are designed as per the standard procedure which we followed during manual preparation of the 177Lu-RGD. The solvents are transferred peristaltic pump rather N2 pressure or vacuum used in commercial modules. The total time taken was 75 min (± 5 min) including cleaning and reaction time. The product formed was clear, colorless and pH was found 5.5 (± 0.5). The gentisic acid was added at the end of the reaction in to product vial and RCP was more than 99.0 % using iTLC and HPLC for 5 days. The product yield was obtained 97.0 % (± 1.5 %) in all the batches produced.

Conclusions and References: All the physiochemical quality parameters of the 177Lu-RGD was found satisfactory using automated synthesis module. This system is not only reducing the dose of the occupational worker but helping in the reproducible results.

Abstract ID: 104: Scaling up of production of kit for the preparation of 99mTc HSA-nano-colloid injection: Our experience

Richa Tiwari, Archana S. Ghodke, Uma Sheri Kumar, H. M. Sheela, Vijay B. Kadwad, Usha Pandey

Department of Atomic Energy, Board of Radiation and Isotope Technology, Mumbai, Maharashtra, India

Introduction: A sentinel lymph node (SLN) is the first lymph node to which cancer cells are most likely to spread from a primary tumour. User-friendly, single component kit for the preparation of Tc-HSA-Nanocolloid injection (Tc-HSA-NC) (Code: TCK-53) is being routinely produced and supplied by BRIT since 2013 for sentinel lymph node imaging / lymphoscintigraphy. In terms of interstitial injections for lymphatic studies, particle size plays a pivotal role in biological behaviour and hence the clinical application.

Materials and Methods: Each kit vial contains 5.0 mg of human serum albumin (20% HSA), 2 mg Na2HPO4, 0.5 mg of ascorbic acid and 0.5 mg SnCl2.2H2O in freeze dried form. Production of HSA nano-colloid injection involves addition of required amount of raw materials into nitrogen purged water for injection followed by dispensing and lyophilisation under aseptic conditions. As biodistribution of nanoparticles are governed by particle size / surface charge, generation of controlled size of HSA nano-colloid in range of 50 – 200 nm for lymphoscintigraphy is technically demanding. This is mainly influenced by reaction parameters such as pH of the reaction mixture which in turn is dependent on the volume/concentration of stannous chloride and disodium hydrogen phosphate, drop rate, method of stirring / heating and cooling of the ingredients etc. Hence, manufactures find it easy to produce small batch size of HSA-Nanocolloid injection for better control of reaction parameters. In the present study in order to cater to the increasing demand for HSA nanocolloid kits, scaling up of production of HSA nano-colloid batch from 100 vials to 200 vials was standardized after careful optimization of reaction parameters and techniques.

Results: Ten consecutive batches of 200 vials each were produced and QC parameters as per RPC approved monograph were studied. Radiochemical purity (RCP) was found to be above 98% indicating integrity of labelled product. Particle size distribution of consecutive batches were found to be between 70 – 180 nm for >80% of the particles (RPC monograph: >80 % between 50 – 200 nm). All other physicochemical and biological tests complied with QC monograph.

Conclusions and References: After scaling up of the production batch, more than 2,000 kit vials were supplied to various Nuclear Medicine Centers across India with utmost customer satisfaction. Kit formulation is being carried out as per cGMP, ISO 9001:2015, and ISO 13485:2016. The scaling up of Tc-HSA-NC kit production enabled better logistics at BRIT end and reduced waiting period for customers.

Abstract ID: 105: Development of 99mTc-pyrophosphate injection (99mTc-PYP) for potential use in the diagnosis of cardiac amyloidosis

Richa Tiwari, Archana S. Ghodke, Uma Sheri Kumar, R. Krishnamohan, Vijay B. Kadwad, Usha Pandey

Department of Atomic Energy, Mumbai, Maharashtra, India

Introduction: Clinical significance of the Tc-PYP scan in the diagnosis and management of cardiac amyloidosis is well proven over the years. Tc-PYP scan can also detect bone uptake that may be suspicious for malignancy. At present BRIT supplies Sn-PYP (Code: TCK 38) kit for blood volume studies; it is often observed that the clinicians use this kit for the diagnosis of cardiac amyloidosis by modification of labelling procedure at hospital end. In order to cater the demands of nuclear medicine physicians, present study was taken up to standardize indigenous Tc-PYP kit formulation.

Materials and Methods: Developed kit vial contains 12 mg of Sodium pyrophosphate with 3 mg of SnCl2. 2H2O in a freeze dried form and standardized labelling procedure involves direct addition of freshly eluted 99mTc-sodium Pertechnatate (10 – 50 mCi / 0.37 – 1.85 GBq) into freeze dried vial with an incubation of 10 min at RT. In order to assess the kit formulation, six consecutive batches of 100 vials each, kit for the preparation of 99mTc-PYP injection were prepared and tested for all quality control parameters.

Results: Initially, the QC parameter were studied with respect to bone imaging. The radiochemical purity (RCP) of 99mTc-PYP injection prepared was > 95 %. Biodistribution studies were carried out in Wistar rats. Percentage of injected activity per gram organ (% IA/organ) at femur bone was found to be >1.5 % indicating the formulation can be used for bone imaging.

Conclusions and References: Our studies established that single component kit for the preparation of Tc-PYP injection is suitable for bone imaging. One step labelling procedure is simple and user-friendly. Further studies on possible use of developed Tc-PYP injection for cardiac amyloidosis is in progress.

Abstract ID: 107: 44Sc – A versatile radio isotope for radiopharmaceutical product basket: Recent development

R. K. Vaishnav¹, N. T. Bivinjith¹, Ashok R. Chandak^1,2, M. K. Ray¹, Sandip Basu¹

¹Radiation Medicine Centre, BARC, ²Board of Radiation and Isotope Technology, Mumbai, Maharashtra, India

Introduction: PET’s has gained prominence due to its superior image resolution, enhanced diagnostic accuracy, and higher sensitivity. One such promising PET isotope is Scandium-44 (⁴⁴Sc) which is a positron emitter with 94.27% of its decays occurring via positron emission and 5.73% via electron capture to its daughter isotope, Calcium-44 (⁴⁴Ca). It has a positron energy of 632 keV, and a half-life of 3.97 hours. A notable feature of its decay lead to the 1157 keV high-energy gamma ray. These features highlight 44Sc as a potentially superior diagnostic radiotracer for PET imaging, further driving scientific interest in its development and application. Moreover, ⁴⁴Sc holds potential as a theranostic radioisotope. It can be paired with Scandium-47 (⁴⁷Sc) for therapeutic applications, as both isotopes share similar chemical properties governed by the trivalent ion Sc³⁺.

Materials and Methods: ⁴⁴Sc can be produced using two main methods. The first is cyclotron-based production, which involves the irradiation of enriched Calcium-44 (⁴⁴Ca) targets via the nuclear reactions ⁴⁴Ca (p, n)⁴⁴Sc or ⁴⁴Ca(d,2n)⁴⁴Sc with a challenge of the co-production of (⁴⁴mSc). The second production route is through the ⁴⁴Ti/⁴⁴Sc generator. The long half-life of the parent isotope, Titanium-44 (⁴⁴Ti) (60 years), enables continuous elution of ⁴⁴Sc from the generator for daily use. AG 1X-8 and TEVA resins enable high elution yields (up to 97%) in small volumes of dilute oxalic acid (C₂H₂O₄) and hydrochloric acid (HCl) mixtures, making the generator system more efficient and long-lasting.

Results: Scandium-44’s chemistry is dominated by the trivalent state (Sc³⁺), which facilitates its coordination with chelators like DOTA. This is advantageous because DOTA-derivatized biomolecules, including dimeric cyclic RGD peptides, PSMA, bombesin analogs, folic acid conjugates, and antibody fragments, can be easily labeled with ⁴⁴Sc. When comparing ⁴⁴Sc with ⁶⁸Ga, revealed that noise ratio and standardized uptake values (SUVs) were similar between the ⁶⁸Ga-PSMA-11 and ⁴⁴Sc-PSMA-617. Few preclinical and clinical studies in between ⁴⁴Sc with ⁶⁸Ga was found to be favorable with ⁴⁴Sc, with optimal tumor delineation and higher tumor-to-background ratios.

Conclusions and References: Scandium-44 (⁴⁴Sc) holds great promise for future clinical PET applications due to its favorable decay characteristics, suitable half-life, and versatile chemistry. Its ability to be paired with therapeutic isotopes for theranostic applications and promising probe with labeled monoclonal antibodies for imaging. We are on the verge of production and/or procurement of ⁴⁴Sc for our institutional research and development, ⁴⁴Sc has the potential to surpass ⁶⁸Ga and become a key radioisotope in diagnostic and pre-therapeutic applications.

Abstract ID: 109: 44Sc – A versatile radio isotope for radiopharmaceutical product basket: Recent development

R. K. Vaishnav¹, N. T. Bivinjith¹, Ashok R. Chandak^1,2, M. K. Ray¹, Sandip Basu¹

¹Radiation Medicine Centre, BARC, ²Board of Radiation and Isotope Technology, Mumbai, Maharashtra, India

Introduction: PET’s has gained prominence due to its superior image resolution, enhanced diagnostic accuracy, and higher sensitivity. One such promising PET isotope is Scandium-44 (⁴⁴Sc) which is a positron emitter with 94.27% of its decays occurring via positron emission and 5.73% via electron capture to its daughter isotope, Calcium-44 (⁴⁴Ca). It has a positron energy of 632 keV, and a half-life of 3.97 hours. A notable feature of its decay lead to the 1157 keV high-energy gamma ray. These features highlight 44Sc as a potentially superior diagnostic radiotracer for PET imaging, further driving scientific interest in its development and application. Moreover, ⁴⁴Sc holds potential as a theranostic radioisotope. It can be paired with Scandium-47 (⁴⁷Sc) for therapeutic applications, as both isotopes share similar chemical properties governed by the trivalent ion Sc³⁺.

Materials and Methods: ⁴⁴Sc can be produced using two main methods. The first is cyclotron-based production, which involves the irradiation of enriched Calcium-44 (⁴⁴Ca) targets via the nuclear reactions ⁴⁴Ca (p,n)⁴⁴Sc or ⁴⁴Ca(d,2n)⁴⁴Sc with a challenge of the co-production of (⁴⁴mSc). The second production route is through the ⁴⁴Ti/⁴⁴Sc generator. The long half-life of the parent isotope, Titanium-44 (⁴⁴Ti) (60 years), enables continuous elution of ⁴⁴Sc from the generator for daily use. AG 1X-8 and TEVA resins enable high elution yields (up to 97%) in small volumes of dilute oxalic acid (C₂H₂O₄) and hydrochloric acid (HCl) mixtures, making the generator system more efficient and long-lasting.

Results: Scandium-44’s chemistry is dominated by the trivalent state (Sc³⁺), which facilitates its coordination with chelators like DOTA. This is advantageous because DOTA-derivatized biomolecules, including dimeric cyclic RGD peptides, PSMA, bombesin analogs, folic acid conjugates, and antibody fragments, can be easily labeled with ⁴⁴Sc. When comparing ⁴⁴Sc with ⁶⁸Ga, revealed that noise ratio and standardized uptake values (SUVs) were similar between the ⁶⁸Ga-PSMA-11 and ⁴⁴Sc-PSMA-617. Few preclinical and clinical studies in between ⁴⁴Sc with ⁶⁸Ga was found to be favorable with ⁴⁴Sc, with optimal tumor delineation and higher tumor-to-background ratios.

Conclusions and References: Scandium-44 (⁴⁴Sc) holds great promise for future clinical PET applications due to its favorable decay characteristics, suitable half-life, and versatile chemistry. Its ability to be paired with therapeutic isotopes for theranostic applications and promising probe with labeled monoclonal antibodies for imaging. We are on the verge of production and/or procurement of ⁴⁴Sc for our institutional research and development, ⁴⁴Sc has the potential to surpass ⁶⁸Ga and become a key radioisotope in diagnostic and pre-therapeutic applications.

Abstract ID: 112: Development of an indigenous automated module for radiochemical synthesis of different Gallium-68 radiotracers

Sudeep Kumar Sahu, Nitin Yuvraj, Sangita Lad, Mukti Kanta Ray, Sandip Basu

RMC, BARC, Mumbai, Maharashtra, India

Introduction: Gallium 68 labelled radiophramaceuticals for PET Imaging has gained prominence in recent years. The present work thus, describes the development and fabrication of an indigenous fixed-tubing based automated radiochemistry module for routine synthesis of [68Ga] Ga-Pentixafor, [68Ga] Ga-FAPI-4, [68Ga] Ga-PSMA-11 and [68Ga] Ga-DOTATATE in a hospital radiopharmacy setup.

Materials and Methods: The indigenous automated module was comprised of (i) control unit and (ii) chemical processing unit. Control unit was based on customized STM32 microcontroller board. The controller was operated by human machine interface (HMI), for sending command to hardware controller board. Active graphical user interface (GUI) was provided to monitor various reaction parameters. Chemical processing unit was made to have four solvent reservoirs for loading (a) 512 µL of acidified NaCl (0.2N HCl in 5M NaCl) for eluting the pre-concentrated [68Ga]GaCl3 from SCX cartridge, (b) 2 mL of ultrapure water for rinsing preconditioned SPE cartridges (C18/tC18), post loading reaction mixture in SPE cartridges, (c) 1 mL of 50% aqueous ethanol for eluting the final product from SPE cartridges and (d) ⁓15 mL of saline for diluting the final radiolabeled products. The unit was equipped with reactor placed inside the indigenously fabricated lead shielded thermostat controlled dry heater. Unit has provision for eluting the [68Ga] GaCl3 either from any commercial 68Ge/68Ga generator or [68Ga] GaCl3 obtained directly from cyclotron route through peristaltic pump. The flow of all these reagents was controlled using solenoid valves connected by TEFZEL tubing. Reactions for each of these radiotracers were carried out at 95oC for 8 minutes in 1M CH3COONa buffer containing 30 µg of each of these peptides with total synthesis time of ⁓15 minutes.

Results: Using our indigenous radiochemistry module, we could successfully formulate clinical doses (⁓0.94 GBq of each of these radiotracers) of [68Ga] Ga-FAPI-4(n=22), [68Ga] Ga-Pentixafor (n=9), [68Ga] Ga-PSMA-11 (n=43) and [68Ga] Ga-DOTATATE (n=78) with non decay corrected radiochemical yield and radiochemical purity of all the products were >84% and >98% respectively. All the produced radiotracers were clear, colorless, while pH were ⁓5.5, the endotoxin limit were <25 EU/mL and were sterile. Each of these radiotracers formulated in our indigenous radiochemistry module, on clinical investigations in various oncological and non-oncological patients exhibited desired outcome.

Conclusions and References: The excellent clinical results of each of these radiotracers ensured the maximum utility of our indigenously developed automated module. This development offers an affordable availability of these 68Ga-based radiotracers for patients at small scale nuclear medicine centers without any available commercial 68Ga-based radiochemistry module.

Abstract ID: 149: Performance of new automated solvent extraction module (AUTOSOLEX) for separation of 99mTc from low specific activity 99Mo and preparation of different diagnostic radiopharmaceuticals: RMC experience

Mukti Kanta Ray, Sudeep Sahu, Rajib Manna, Anchal Chawla, Sandip Basu

Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: This study examined the use of an advanced version of the fully automatic, AUOTOSOLEX Module developed by Board of Radiation & Isotope Technology in a Nuclear Medicine Facility setup for solvent extraction of 99mTc from low specific activity 99Mo and in radiolabeling & quality control of different SPECT tracers like [99mTc] Tc-MIBI, [99mTc] Tc-DTPA, [99mTc] Tc-EC and [99mTc]Tc-DMSA.

Materials and Methods: The automated process involves extraction of 99mTc from 99Mo from an aqueous phase (5M NaOH) with organic phase (Methyl Ethyl Ketone) and later the MEK was evaporated by heating (at 75°C) followed by reconstitution by 0.9% saline and the final product collected through 0.22 µ membrane filter. The solvent extraction entire setup is housed inside a cuboidal lead chamber with a see-through lead glass. The steps were controlled by touch key pad interface handled remotely by user. Around 300-500 mci of carrier added molybdenum [BRIT#TCM-2] was loaded in the designated vessel of the AUTOSOLEX Module installed at RMC by BRIT (Manufacturer). The separation of [99mTc] technetium was performed as per SOP provided by the manufacturer. The sterile 99mTc-NaTcO4 stock solution was used for preparation of different [99mTc] technetium based radiopharmaceutical.

Results: The sodium pertechnetate (NaTcO4) was extracted with efficiency of ~80%, RAC 90-100mCi/mL and was clear, colourless, pH ~6.0 (n=5). The [99Mo] molybdenum breakthrough was ˂ 0.01%, residual MEK was ˂10 ppm, aluminum was ˂10 ppm. The physical appearance of all prepared radioconjugates products was clear and colorless with pH ranging 5.5–7.0 and RAC 8-10 mCi/ml. RCP of all the radioconjugates were estimated >98% by chromatography method. [99mTc]Tc-MIBI (Whatman paper-3, methanol (100%), Rf -1.0) (n=25), [99mTc]Tc-DTPA (Whatman paper-3, saline, Rf- 1.0) (n=15), [99mTc] Tc-EC, (Whatman paper-3, saline, Rf-1.0)(n=8), [99mTc]Tc-DMSA (Whatman paper-3, saline, Rf -1.0) (n=6). The in-vitro stability of all products were up to 6 h post-radiolabeling (RCP>98%) on storage at room temperature (25oC).

Conclusions and References: The advanced AUTOSOLEX solvent extraction module is a dependable method for separation of [99mTc] technetium from low specific activity [99Mo] molybdenum, when fission [99Mo] molybdenum is not available. It ensures that patient services are not hampered in the absence of regular supply of column/dry generators. The radiation doses received by occupational workers during the operation of the described Autosolex Module is drastically minimized compared to other available solvent extraction methods. Acknowledgements: The authors acknowledge the support and help received from BRIT in installation and operation of the new Autosolex module.

Abstract ID: 150: An attempt to develop 177Lu-labeled bio-ceramic microspheres for trans-arterial radio-embolization of hepatocellular carcinoma

Sayan Das, Tapas Das¹, Santanu Dhara²

SRF, Biomaterials and Tissue Engineering Group, School of Medical Science and Technology, IIT Kharagpur, ²School of Medical Science and Technology, IIT Kharagpur, Kharagpur, West Bengal, ¹Radiopharmaceutical Division, BARC, Mumbai, Maharashtra, India

Introduction: Trans-Arterial Radio-Embolization (TARE) is a radionuclide therapy that entails the precise deployment of beta particle (β-) emitting radioactive microspheres, (20 μm<d> 60 μm) adjacent to hepatic tumours. The major drawbacks of the currently available therapeutic microspheres are non-trackability in-vivo, non-biodegradability and neutron irradiation step of the non-radioactive microspheres. To address the limitations, herein we have developed a 177Lu- radiolabeled novel bio-ceramic microspheres (BCMSs) for TARE of Hepato-Cellular Carcinoma (HCC).

Materials and Methods: Briefly, the BCMSs is prepared using emulsion crosslinking method using novel biomineral slurry, followed by sintering (700oC). Labeling of BSMS microspheres with 177Lu [T1/2= 6.65 d, Eβ (max) = 497 KeV (78.6%), Eγ (max) = 208 keV (11.1%)] was achieved by adding 0.1 mL of 177LuCl3 solution (370 MBq) in 5 mgmL-1 of the BCMS suspension (pH 6, 1 hour). Several reaction parameters, such as concentration of the BCMS particles, pH, incubation time and temperature to get 177Lu-BCMS with maximum radiochemical yield (RCY). Paper chromatographic analysis are performed to check the radiochemical purity (RCP) of the 177Lu-BCMS. The adsorption capacity of the BCMS was determined and plotted using the suitable algebraic form and fitted with the sorption isotherms to understand the sorption mechanism.

Results: The developed BCMSs have average diameter of ~48 μm, average porosity ~15 nm and high surface area of 25.52 m²g⁻¹ with the presence of characteristics spectroscopic peaks of the BCMS before and after radiolabeling. The BCMSs are semi-crystalline (Xc = 0.0621) in nature with average crystallite size of 1.11 nm. Spectroscopic analysis denotes uniform distribution of Lu over the microsphere surface. The RLY and RCP of the 177Lu-BCMS were found to be ~88.28% and ~98.6%, respectively. The adsorption of Lu3+ over BCMS follows Langmuir-Freundlich (L-F) adsorption isotherm denoting both physical and chemical adsorption.

Conclusions and References: Due to the comparatively higher specific activity [~740 MBq /μg] of 177Lu, a therapeutic dosage (Assuming ~4 GBq (~100 mCi) of 177Lu activity is required for TARE therapy) of 177Lu-BCMS may be formulated utilising 5-10 mg of BCMS particles, which would be considerably less than that utilized in 166Ho-labeled polylactic acid microspheres (700 mg). The moderate energy γ radiation of 177Lu and 6.65 days half-life also allow long-term SPECT-CT follow up post microsphere administration. However, in-vivo behaviour of 177Lu-BCMS needs to be thoroughly evaluated in suitable animal models to understand its potential for TARE application.

Abstract ID: 201: Preparation and preliminary analysis of 68Ga-NOTA-Fab-trastuzumab for diagnostic imaging of HER2 expressing breast cancers

Suresh Suthar, Sneha Mithun, Kinnari Chitnis, Vivek Kumar, Vishal, Sneha Shah, Venkatesh Rangarajan

Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Homi Bhabha National Institute, Deemed University, Mumbai, Maharashtra, India

Introduction: Trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor type 2 (HER2), utilized for the treatment of HER2-positive breast cancer. Radioimmunotherapy, utilizing radiolabeled trastuzumab, holds promise as a potential solution. Fragmentation of trastuzumab into Fab fragments allows for faster uptake and clearance, enhancing its suitability for radioimmunotherapy. The aim of this study was to radiolabel fragmented Trastuzumab with 68Ga and assess its stability.

Materials and Methods: Immobilized Papain was used for enzymatic digestion of Trastuzumab to obtain Fab fragments, followed by their purification and characterization. Obtained Fab fragments were conjugated with p-SCN-Bn-NOTA. Radiolabeling was performed with varying amount of conjugate and radioactive strengths of 68Ga. Radiochemical Purity and stability over a period of 2 hours was assessed.

Results: Optimal conditions for the fragmentation of trastuzumab were identified, with higher yields achieved using increased incubation time. HPLC analysis confirmed the successful generation of Fab fragments with >80% yield and high purity. Radiolabeling of the fragments demonstrated promising results with >98% mean RCP.

Conclusions and References: The standardized methodology developed in this study provides a foundation for further research into the use of radiolabeled fragmented antibodies for cancer imaging and diagnosis.

Abstract ID: 203: Preparation and preliminary analysis of 99mTc-HYNIC-TRASTUZUMAB-Fab for diagnostic imaging of HER2 expressing breast cancer

Vivek Kumar, Sneha Mithun, Suresh Suthar, Kinnari Chitnis, Vishal, Sneha Shah, Venkatesh Rangarajan

Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Homi Bhabha National Institute, Deemed University, Mumbai, Maharashtra, India

Introduction: Preparation and Preliminary Analysis of 99mTc-Hynic-Trastuzumab-Fab for Diagnostic Imaging of HER2 Expressing Breast Cancer.

Materials and Methods: Fragmentation of trastuzumab into Fab fragments was performed using enzymatic digestion with immobilized papain. Purification and characterization of resulting Fab fragments was conducted. Conjugation of F (ab)’ fragment with Succinimidyl-Hynic- hydrochloride and subsequent radiolabeling with varying amounts of conjugate and 99mTc were performed. Radiochemical purity and post radiolabeling stability of 99mTc-HYNIC- F (ab)’-Trastuzumab over a period of 6 hours were assessed.

Results: Optimal conditions and appropriate reagent concentrations for trastuzumab fragmentation, conjugation and radiolabeling were identified. Higher yields were achieved with increased incubation time of the radiolabeled conjugate. HPLC analysis confirmed successful generation of Fab fragments with >80% yield and high purity. Radiolabeling of fragments with 99mTc showed promising results with >98% mean radiochemical purity and stability for up to 6 hrs.

Conclusions and References: The standardized methodology for preparation of 99mTc-HYNIC- F (ab)’- Trastuzumab gave good radiochemical purity with sufficient in-vitro stability. It paves the way for exploring radiolabeled fragmented antibodies such as 99mTc-HYNIC-Trastumab-Fab for cancer diagnosis and staging.

Abstract ID: 69: Enhancing therapeutic efficacy of trastuzumab via nuclear localization sequence for targeted HER2-positive breast cancer radiotherapy

Soumi Kolay, Kusum Vats, Rohit Sharma, Mohini Guleria, Jeyachitra Amirdhanayagam, Naveen Kumar, Archana Mukherjee, Tapas Das

Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Introduction: Trastuzumab is an FDA-approved monoclonal antibody for HER2-positive breast cancer. However, it faces resistance in many patients, prompting the need for improved therapies. Radiolabeling Trastuzumab with lutetium-177 ([177Lu] Lu-DOTA-Trastuzumab) enhances its radiotherapeutic efficacy and helps overcome resistance, but also leads to off-target accumulation in organs like the liver and spleen. To address this, further modifications are required. A promising approach is incorporating a nuclear localization signal1 (NLS-PKKKRKV) into Trastuzumab to improve cellular uptake and radiotherapeutic efficacy, potentially overcoming resistance and reducing off-target effects.

Materials and Methods: An azide-functionalized NLS sequence was synthesized, and DOTA, a bifunctional chelator for radiolabeling with 177Lu, was conjugated at the alpha-amino group of lysine within the NLS. DBCO-modified Trastuzumab was conjugated with azide-functionalized NLS-DOTA using a Copper-free click chemistry route. This approach, which simultaneously conjugates DOTA and NLS at the same antibody site, enabled the determination of the drug-to-antibody ratio (DAR) via UV-Vis spectrophotometry. Copper (II) Arsenazo and Bradford protein assays quantified the DOTA and protein content in DOTA-NLS-Trastuzumab and DOTA-Trastuzumab. Both conjugates achieved over 95% radiochemical purity when radiolabeled with 177Lu. Cell uptake and internalization studies were conducted on HER2-positive SK-OV-3 and SK-BR-3 cells. Confocal microscopy assessed the cellular localization of unlabeled DOTA-NLS-Trastuzumab and DOTA-Trastuzumab in HER2-positive SK-OV-3 and HER2-negative MDA-MB-231 cells. Biodistribution was evaluated in SCID mice bearing SK-OV-3 xenografts at 24- and 48-hours post-injection.

Results: Purification of the synthesized peptide via HPLC and subsequent HR-MS analysis revealed molecular ion peaks at 474.9713 and 356.4794 m/z, confirming successful synthesis. FT-IR analysis indicated a peak at 2102 cm⁻¹, consistent with azide incorporation in the peptide chain. DAR calculations revealed 6.2±0.8 for DOTA-Trastuzumab and 5.0±1.0 for DOTA-NLS-Trastuzumab. In vitro studies showed that [177Lu] Lu-DOTA-NLS-Trastuzumab had lower surface binding but significantly enhanced internalization in HER2-positive cells compared to its unmodified counterpart. Confocal microscopy confirmed improved cellular penetration of the NLS-modified antibody in HER2-positive cells, with no uptake in HER2-negative cells. Ex vivo studies corroborated these findings, showing reduced off-target accumulation of [177Lu] Lu-DOTA-NLS-Trastuzumab.

Conclusions and References: The incorporation of an NLS significantly enhanced the internalization of [177Lu] Lu-DOTA-Trastuzumab in HER2-positive cancer cells, while also improving target specificity. This modification shows strong potential to increase the effectiveness of targeted radiotherapy and minimize off-target effects, making it a promising strategy for overcoming limitations in current treatments.

Abstract ID: 144: [68Ga]Ga-DOTA-mDesmo: A novel radiotracer targeting V1b receptors for functional and anatomical delineation of corticotropinoma

Somit Pandey, Rama Walia, Gurvinder Kaur, Nivedita Rana, Kumud Pandav, Rajender Kumar, Bhagwant Rai Mittal, Jaya Shukla

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: The diagnosis of Cushing’s syndrome is challenging. Among all the sources, ACTH-dependent pituitary source (Cushing’s disease or corticotropinoma) constitutes 80% of the cases. One of the pathological characteristics of corticotropinoma is the unique expression of V1b receptors. In this work, a novel radiopharmaceutical, [68Ga] Ga-DOTA-mDesmo, has been developed by modifying natural arginine vasopressin (AVP) for the functional and anatomical delineation of corticotropinoma.

Materials and Methods: The binding affinities of wild-type AVP and [68Ga] Ga-DOTA-mDesmo with the V1b receptor were assessed using in silico tools: AlphaFold2 for 3D structure prediction, GROMACS for 250ns MD simulations, Autodock-GPU for docking, PyMOL for visualization, and LigPlot+ for interaction analysis. The radiolabeling was standardized followed by quality control tests. In vitro binding assay with the recombinant human V1b receptor and ACTH-releasing activity test using corticotropinoma cells were conducted. Biodistribution studies were performed on healthy male Wistar rats. The PET/CT pilot study was conducted on 22 patients (17 females and 5 males, mean age of 36 ± 12) after institutional ethics committee clearance and written informed consent from patients. Regional brain PET/CT imaging was done at 30-35 min after intravenous administration of 111 ± 29.6 MBq [68Ga] Ga-DOTA-mDesmo.

Results: AVP and [68Ga] Ga-DOTA-mDesmo showed good binding energies of -14.55 kCal/mol and -13.98 kCal/mol, respectively, for the V1b receptor. [68Ga]Ga-DOTA-mDesmo was produced with a high radiochemical yield (96 ± 3.3%) and purity (>99%). It demonstrated a shelf-life and in vitro serum stability for up to 4 h. [68Ga] Ga-DOTA-mDesmo was sterile and endotoxins (7.3 ± 1.3 EU/V) were well within the range (limit < 175 EU/V). DOTA-mDesmo stimulated over 200% ACTH release in corticotropinoma cells. [68Ga]Ga-DOTA-mDesmo achieved a maximum binding of 44 ± 2.2 % with the V1b receptor. Excess 20 µM DOTA-mDesmo resulted in a 50% blocking effect in the binding. Animal biodistribution studies showed a high %ID/g in the kidneys (7.37 ± 0.58) and urinary bladder (4.32 ± 0.48), suggested renal as main route of excretion. Negligible counts in the pituitary suggested non-expression of the V1b receptors in healthy pituitary. Out of 22 patients, 6 had macroadenoma, 11 had microadenoma, and 5 served as controls. Significant uptake of [68Ga]Ga-DOTA-mDesmo was seen in the corticotropinoma with a mean SUVmax of 2.07 ± 0.65 (range 1.0-3.3), compared to a background SUVmax of 0.11 ± 0.03. No uptake was seen in the pituitaries of control patients.

Conclusions and References: The favorable binding and selective uptake of [68Ga] Ga-DOTA-mDesmo highlight its potential for accurate functional and anatomical localization of corticotropinoma.

Abstract ID: 99: Evaluation of predictive model for tumor absorbed dose in patients with inoperable/metastatic neuroendocrine tumor undergoing 177Lu-DOTATATE therapy employing quantitative SPECT/CT and 68Ga-DOTANOC PET/CT

Komalpreet Kaur, Nivedita Rana, Jaya Shukla, Vijayta D. Chadha, Rajender Kumar, Ashwini Sood, Bhagwant Rai Mittal

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: 177Lu-DOTATATE has emerged as a promising theragnostic agent in treating neuroendocrine tumors (NET) as well as facilitating post-therapy imaging and image-based quantification to measure the response to therapy. For dosimetry, necessary absolute quantification has become possible using quantitative SPECT/CT that can also be calibrated to provide standardized uptake values (SUV) and can further be used for estimating the tumor absorbed dose delivered in one cycle. The aim of the study was to develop and evaluate a predictive model for tumor absorbed dose based on 177Lu-DOTATATE quantitative SPECT/CT as well as 68Ga-DOTANOC imaging in patients with inoperable/ metastatic NET.

Materials and Methods: The prospective study was performed in Department of Nuclear Medicine, PGIMER, Chandigarh. A total of 16 inoperable/ metastatic NET patients (10 F/6 M; mean age 46±5; range 10-72 years) receiving 177Lu-DOTATATE were included in the study. Post-therapy regional quantitative SPECT/CT were acquired in all the patients at 24 hours and data was reconstructed and analyzed using Qmetrix (GE Healthcare) software. Quantitative parameters such as SUVmean and tumor volume obtained by SPECT/CT were compared to that obtained by 68Ga-DOTANOC PET/CT using paired t-test and correlation was obtained using Karl Pearsons coefficient (significance level p=0.05). The mean absorbed dose for tumor estimated using MIRD after 177Lu-DOTATATE therapy and the SUVmean of tumor on 68Ga-DOTANOC PET/CT images, were compared by correlation and linear regression analysis.

Results: The paired T-test showed statistically significant correlation between SUVmean of tumor in 177Lu-DOTATATE SPECT/CT and 68Ga-DOTANOC PET/CT (R= 0.721, p<0.001). An average mean absorbed dose of 11±7.2 Gy was delivered to tumor in one 177Lu-DOTATATE therapy cycle. Linear regression analysis showed that estimated absorbed dose after 177Lu-DOTATATE therapy could be predicted as follows: Tumor absorbed dose (Gy)= 18.45-0.100 (SUVmean of 68Ga-DOTANOC PET/CT).

Conclusions and References: Absolute Uptake of 177Lu-DOTATATE and SUVs derived from quantitative SPECT/CT using Q.Metrix is reproducible and may be used for dosimetric analysis and response evaluation with higher accuracy. Also, statistically significant correlation was observed in tumor volumes b/w interim PET/CT and SPECT/CT (R=0.552, p=0.050). Moreover, Quantitative measurements on pretherapy 68Ga-DOTANOC PET/CT was found to be predictive of the absorbed doses by tumors after 177Lu-DOTATATE therapy and thus can be used in guiding the personalized therapy. However, larger samples are required to make the predictive model more robust and accurate.

Abstract ID: 167: 177Lu/188Re-selective internal radionuclide therapy: Absorbed dose estimation using absolute, high-resolution, Gafchromic film dosimetry and OLINDA

Sejal Chopra, Jaya Shukla, Arun S. Oinam, Gaganpreet Singh, Komalpreet Kaur, Bhagwant Rai Mittal

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: Personalized dosimetry is crucial for overcoming variability in absorbed doses (AD) in radionuclide therapies. We introduce a cost-effective, high-resolution Gafchromic film dosimetry using a custom-made phantom for 188 Re and 177Lu.

Materials and Methods: AD estimates as function of radioactivity, with Percentage Depth Dose and lateral spread distributions were calculated at 0.1 mm increments. Based on dose fall-off curves, volume of irradiation sphere generated by isotropic emission by point source was quantified and termed as Dosimetric Volume Unit (DVU). DVU dosimetry was employed in ten patients undergoing 188Re/177Lu-SIRT, comparing results with OLINDA/EXM® V2.0. Post-therapy regional SPECT/CT for OLINDA dosimetry were conducted at 24, 48, 72, 96 and 120 hours, with late imaging at 1, 2, and 3 months after 177Lu-SIRT. In DVU dosimetry, lesion activity (%IA) was calculated via manual ROI processing and Q-Matrix software. SPECT functionalized tumor volume calculated from pre-dosimetry 99mTc-Microspheres SPECT/CT.

Results: DVU dimensions for 188Re and 177Lu were 4.8 x 4.8 x 7.4 mm and 3.7 x 3.7 x 1.6 mm respectively. Overall, mean cumulative absorbed-dose (CAD) and absorbed-dose rate (ADR) for 177Lu/188Re-SIRT calculated by OLINDA was 20(51-17) Gy and 24 (63-14) mGy/MBq respectively. For film dosimetry, manual and Q-matrix derived % IA in liver lesions were 46±14 and 27±12 respectively. DVU dosimetry revealed 2.4±1.5 times higher CAD and ADR values of 54(81-30) Gy and 78(174-24) mGy/MBq in comparison to OLINDA. OLINDA calculated mean lesion residence time for 188Re-Microspheres was 6.2 ± 2.3 hours. Manual and Q-matrix derived % IA in liver lesions were 21 ± 3 and 25 ± 9 respectively. DVU dosimetry revealed 3.6 ± 1.1 times higher CAD and ADR values of 81(96-68) Gy [vs 21(28-18) Gy for OLINDA] and 87 (119-64) [vs 31(37-21)] mGy/MBq. For 177Lu, early time-point based OLINDA dosimetry revealed a lesion residence time of 45 ± 10 h. Corresponding CAD and ADR values were 15 ± 8 Gy and 11 ± 5 mGy/MBq respectively. DVU dosimetry revealed 1.9 ± 0.5 times higher CAD and ADR values of 29 ± 15 Gy and 30 ± 21 mGy/MBq. Furthermore, in same cohort, late-time point imaging increased (OLINDA) lesion residence time to 184 ± 109 h. Corresponding CAD and ADR values increased to 88 ± 66 Gy and 30 ± 17 mGy/MBq respectively.

Conclusions and References: DVU dosimetry yielded higher CAD and ADR estimates than early-time point OLINDA, and aligning with late-time point estimates, suggesting it could replace multi-point OLINDA, when effective half-life matches physical half-life.

Abstract ID: 212: A comparative study of radionuclide internal dose estimated by two different dosimetry software in Lu-177 trastuzumab therapy

Tejashri Mahanwar, Shubham Ghag, Sneha Shah, Ashish Kumar Jha, Venkatesh Rangarajan

Department of Nuclear Medicine and Molecular Imaging Technology, Tata Memorial Centre, Navi Mumbai, Maharashtra, India

Introduction: In nuclear medicine, radiopharmaceuticals are used for diagnosis or therapy. Radiopharmaceuticals are administered in systemic circulation via intravenous/intra-arterial/oral route are distributed in the various organ and tumor according to the bio distribution and pathological condition of the patient. Hence, it becomes utmost important to assess radiation dose delivered to tumor as well as normal organs. The internal radiation dosimetry can be can be performed using internal medical radiation dosimetry (IMRD) technique. Several software are available in the market for performing dosimetry, which produces variable dosimetry results. In this study, we aim to compare two commercially available dosimetry software i.e. Dosimetry Toolkit+ Olinda Exm 2.0 and QDOSE+.

Materials and Methods: In total 12 histologically proven HER2+ metastatic breast cancer patients who underwent Lu-177-trastuzumab therapy (no.7) or pre-therapeutic dosimetry scan (no. 5) were included in this study. The mean dose of Lu-177 Trastuzumab administered to the therapeutic and pretherapeutic dosimetry scan patients were 3885±37 MBq and 407±44 MBq respectively. Whole-body planar and SPECT images were acquired at 4 h, 24 h, and 72 h time points post-infusion of 177Lu Trastuzumab. The imaging data were processed using Dosimetry Toolkit + Olinda Exm 2.0 (Hybrid method) and QDOSE+ (Planner method) application independently to estimate mean absorbed dose (mGy/MBq) for normal organs i.e. liver, spleen, kidneys, heart, and tumour. Both the software use mono- exponential curve fitting for normalized cumulated activity (NCA) estimation. Paired t-test employed to find the significant difference in the absorbed dose calculated for the normal organ using these two software.

Results: The mean absorbed dose calculated for liver, spleen, kidneys, heart and tumor were 1.71±1.11, 1.03±0.85, 0.64±0.43, 1.09±1.03, 8.43±8.35 mGy/MBq respectively by Dosimetry Toolkit and 1.45±0.64, 1.08±0.41, 1.45±0.60, 1.30±0.63, 6.51±3.62 mGy/MBq respectively by QDOSE+ software. Paired t-test suggest no significant difference in absorbed dose calculated for lung (p-value=0.073) heart (p- value=0.654) and spleen (p-value=0.792) however significant difference was noted for the kidneys (p- value=0.002).

Conclusions and References: Our study suggests that the absorbed dose calculated by both Dosimetry Toolkit and QDOSE+ software are comparable. Further study will require with the larger dataset.

Abstract ID: 46: Single centre experience of diagnostic accuracy of 18F-FDG PET/CT in pyrexia of unknown origin

Medha Dutta, Suneetha Batchu, Mohan Roop Jayanthi

AIG Hospitals, Hyderabad, Telangana, India

Introduction: Pyrexia of Unknown Origin (PUO), also known as (a.k.a) Fever of Unknown Origin (FUO) is defined as persistent fever above 38.3°C (100°F) that evades diagnosis for at least 3 weeks, including 1 week of investigation in hospital. It is a puzzling clinical problem in medicine that needs amalgamation of various diagnostic practices to establish the precise diagnosis. Whereas conventional imaging modalities depend more on anatomical changes caused by disease processes, PET/CT combines anatomical and functional assessment, thus increasing sensitivity and specificity. We, at our institute, have evaluated the diagnostic performance of 18F-FDG PET/CT in 142 patients who presented themselves with PUO and compared their results to the fallouts of laboratory, histopathological, microbiological investigations and/or response to therapy.

Aims and Objectives: This is a retrospective observational study to assess the role of 18F-FDG PET/CT in evaluation of PUO in a single centre tertiary level hospital based population in an Indian metropolitan city. The study aims to evaluate Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of using 18F-FDG in pinpointing the focus of cause of PUO and thereby tunnel guiding the line of action. To determine if 18F-FDG can be used as an early diagnostic modality in such patients, thereby dwindling the financial burden of undergoing a plethora of diagnostics and allowing early hospital discharge.

Materials and Methods: Patients were scanned with 18F-FDG from head to toe using Siemens Biograph 16 scanner (Siemens, Germany). Before F-18 FDG PET/CT study day, patients were instructed to fast for 6-8 hours and blood glucose levels were measured before injection. No anti-diabetic medications were to be taken on the day of study, with recent Serum Creatinine within normal limits. Patients were scanned only if their Fasting Blood Sugar (FBS) were between 90-200 mg/dl. All studies were reviewed by two expert Nuclear Medicine physicians, enabling increase in diagnostic accuracy and reducing inter-observer variability.

Results: The final diagnosis included malignancy in 14 patients (9.8%), infectious causes in 65 patients (45.77%), non-infectious inflammatory causes in 23 patients (16.19%) and other causes that got cured on empirical or conservative management without receiving a concrete diagnosis in 40 patients (28.16%). PET/CT successfully contributed to the diagnosis of 99 out of 142 patients with diagnostic accuracy of 64.78%. The sensitivity, specificity, positive predictive value and negative predictive value of PET/CT in our study were 84.33%, 21.42%, 61.40% and 48.0%, respectively.

Conclusions and References: PET/CT is a worthwhile and economical widget to investigate, diagnose and discriminate between different types of etiologies of PUO. It delivers evidence that can precisely direct the treatment strategy and therefore result in improved patient outcome, reduced financial burden and shorter hospital stays.

Abstract ID: 111: Role of 68Ga-FAPI PET/CT in clinically suspected invasive sinonasal fungal infection

Raza Abbas Mahdi, Rajender Kumar¹, Harmandeep Singh¹, Aastha Takkar², Chirag Kamal Ahuja³, Sandeep Bansal⁴, Debajyoti Chatterjee⁵, B. R. Mittal¹, Vivek Lal²

PGIMER, Departments of ¹Nuclear Medicine, ²Neurology, ³Radiodiagnosis and Imaging, ⁴ENT and ⁵Histopathology, PGIMER, Chandigarh, India

Introduction: 68Ga-FAPI PET/CT is emerging as a promising imaging modality in the evaluation of various neoplastic and inflammatory conditions. This study explores its utility in diagnosing invasive sinonasal fungal infections (ISFI), which often present with nonspecific symptoms but can lead to significant morbidity. Conventional imaging modalities, such as CT and MRI, have limitations in differentiating fungal from non-fungal etiologies. 18F-FDG PET/CT can be used, but physiological uptake in the nose, nasopharynx and brain can interfere. Nasal scrapings/culture are used to establish the diagnosis, but it is not positive in all the patients.

Aim and Objectives: 1. To assess 68Ga-FAPI PET/CT in detecting the lesions in patients with clinically suspected ISFI, with initial negative culture. 2. To assess the incremental value of 68Ga-FAPI PET/CT in guiding the site for biopsy.

Materials and Methods: Patients with clinically suspected ISFI, who presented to the neurology and ENT OPD, underwent 68Ga-FAPI-PET/CT after clinical assessment and nasal scraping. Nasal scrapings were subjected to microscopy and culture. Two qualified nuclear medicine physicians studied the images. The maximum standardized uptake value (SUVmax) of lesions, presence and site of extensions were documented. The gold standard for diagnosis was biopsy.

Results: Twenty patients (fifteen men and five women; mean age 46.3 years) with suspected ISFI and negative culture were recruited prospectively, out of which nine patients (eight males and one female) had fungal infection. Most common symptom was headache followed by diplopia, facial numbness, fever, nasal blockade, and hearing loss. FAPI PET/CT demonstrated increased FAPI expression in all the lesions. Median SUVmax was 14.0 (IQ range, 8.75-16.25) in the lesions. Median SUVmax in patients with diagnosis other than fungal infection was 10.4 (IQ range 4.7-13.4). There was no significant difference in median SUVmax between the two groups (p = 0.17 using Mann-Whitney U test). Extra-sinonasal extension were detected in all patients including orbit, pterygopalatine fossa, cavernous sinus, infratemporal fossa and pachymeningeal thickening. Biopsy was done from the FAPI avid site in all patients (eight patients had chronic invasive aspergillosis and one mucormycosis).

Conclusions and References: 68Ga-FAPI PET/CT can be used in culture negative patients with clinically suspected invasive sinonasal fungal infection to delineate the sites of involvement and potential target for guided biopsy, although it cannot differentiate between fungal and non-fungal aetiologies using SUVmax. This signifies the importance of FAPI PET/CT supporting future prospective studies with larger cohort and comparison with FDG.

Abstract ID: 143: Benign presentation of hidden malignancy – 18F-FDG PET/CT unveiling the widespread disease

Harinee Ganesan, Vasanth Madivanane¹, Kabilash Dhayalan¹, Vignesh Hariharan¹, Ragire Sainath¹, Harish Goyal¹, Dhanapathi Halanaik¹

JIPMER, ¹Department of Nuclear Medicine, JIPMER, Puducherry, India

Introduction: The majority of intracranial tumors are a result of metastases from lung carcinoma but the first presentation of lung carcinoma with benign central nervous system symptoms is rare. Despite the advancement in treatment for brain tumors, those with lung metastases to the brain continue to have a dismal survival rate. Here, we report two patients who presented to our hospital with benign symptoms, initially thought to be a primary central nervous system tumor. Later on, with detailed evaluation and radionuclide scans, diagnosed with primary bronchogenic carcinoma with metastasis to the brain. Thus, these cases call for the collaborative effort to diagnose brain metastases and the importance of 18F-FDG PET/CT to confirm primary and baseline staging.

Materials and Methods: A 45 year old female (Patient 1) presented with a history of headache and dizziness for 1 week. NCCT brain was done which showed left thalamic cystic lesion with mild dilated ventricles. CE-MRI brain showed left thalamic ring enhancing cystic lesion with edema and dilated ventricles. Stereotactic brain biopsy revealed metastatic adenocarcinoma. Another 58 year old male (Patient 2) presented with a history of headache and unconsciousness. MRI showed a lesion in the left temporal lobe of the brain. Underwent left temporal craniotomy and biopsy revealed papillary adenocarcinoma. Chest X ray revealed a consolidation in the right middle lobe. In order to characterize the primary and for baseline staging purposes, 18F-FDG PET/CT was done in both the patients.

Results: 18F-FDG PET/CT revealed widespread metastatic disease in both the patients. Patient 1 showed metabolically active primary in the left lung with satellite lesion and metastasis in the peripherally enhancing lesion in the left thalamus with perilesional edema, right supraclavicular, mediastinal, left internal mammary and anterior diaphragmatic lymph nodes, hypoenhancing lesions in the liver and multiple mixed lytic-sclerotic skeletal metastasis. Patient 2 showed metabolically active lesion in the right lung with metastasis in the bilateral supraclavicular, mediastinal, right internal mammary, retroperitoneal and left obturator lymph nodes, bilateral lungs, bilateral adrenal glands, few liver lesions and multiple lytic skeletal metastasis.

Conclusions and References: Despite widespread malignant involvement, the patients were completely asymptomatic & active except for those benign symptoms. These cases emphasize the necessity of prompt and priority-based whole body evaluation of patients with 18F-FDG PET/CT whenever doubtful intracranial lesions are noted, regardless of age and other risk factors.

Abstract ID: 34: Concordance/discordance between Tc-99m sulphur colloid lymphoscintigraphy and methylene blue in case of sentinel lymph node detection

Manisha Pradhan, J. K. Bhagat, Himanshu Pandey, Shailesh Yadav, Purshottam Singh, Ravi Kant Gupta

Bhagwan Mahaveer Cancer Hospital and Research Center, Jaipur, Rajasthan, India

Introduction: Prevalence of breast cancer is unprecedentedly increasing worldwide while the incidence of breast cancer is a major concern in India. But the advanced and modern medicine tackles well the management and treatment of breast cancer. Sentinel lymph node biopsy (SLNB) is a better surgical management option than axillary lymph node dissection. Tc-99m Sulphur colloid (Tc-99m SC) lymphoscintigraphy can be easily performed in a diagnostic nuclear medicine department followed by detecting of sentinel lymph node in Operation Theatre using methylene blue and gamma probe on a same day basis to rule out the presence or absence of nodal involvement respectively.

The objectives are

• 1) To compare the performance of radiotracer (Tc-99m SC) and dye (Methylene blue)

• 2) To measure the agreement between radiotracer and dye in detecting the same lymph nodes.

Materials and Methods: The course of study was performed retro-prospectively at Bhagwan Mahaveer Cancer hospital and Research centre, a tertiary care cancer hospital from 2020 to 2024 in the Nuclear Medicine department and Onco-surgery department. A total of 38 patients were selected ranging from 36 to 79 years, referred to our dept for Tc-99m SC lymphoscintigraphy using 0.22 micrometer milipore filter and scanned under gamma camera (NM 870 GE Healthcare) after which they were sent for SLNB in OT using methylene blue dye and gamma probe (Crystal Photonics Gmbh). The excised lymph nodes were sent for HPE correlation and the reports were analyzed for number of HOT (Detected by Tc-99m SC) /BLUE (Detected by Methylene Blue)/HOT & BLUE (Detected by both)/NOT HOT & BLUE nodes (Not detected by either) respectively. We used McNemar’s test and Cohen’s kappa for statistical analysis for our study set-up to determine Concordance/Discordance between the radiotracer and dye.

Results: No of HOT nodes was 39, no of BLUE nodes was 21, no of HOT & BLUE was 49 and no of NOT HOT & BLUE nodes detected were 34. Chi-square value and p-value of McNemar’s test results are 16.20 and 0.000057 (approx.) respectively. P value is highly significant (p<0.001), which means that there is a statistically significant difference between the detection rates of radiotracer and dye. This suggests that the detection pattern is different whereas Cohen’s kappa score is 0.466 which indicates moderate agreement between Tc-99m SC and Methylene blue in detecting sentinel lymph nodes.

Conclusions and References: Combining the technique of dye, isotope and axillary node sampling improves accuracy further. This is often the practice in clinical settings where dual-modality approaches provide complementary information.

Abstract ID: 148: Exploring sentinel lymph node biopsy outcomes, post-neoadjuvant chemotherapy therapy in breast cancer patients

Priyanka Rawat, Manishi L. Narayan, Farhanul Huda, Nilotpal Chowdhury, Vishal Jain, Meena Negi

AIIMS, Rishikesh, Uttarakhand, India

Introduction: Breast cancer remains a major cause of morbidity and mortality among women worldwide. Neoadjuvant chemotherapy (NACT) has significantly improved tumor response, reducing tumor size and downstaging the disease before surgery. Sentinel lymph node biopsy (SLNB) offers a minimally invasive way to evaluate axillary lymph node status, reducing the risks of axillary lymph node dissection (ALND) such as lymphedema, pain, and shoulder stiffness. Axillary surgical management in patients with node-positive breast cancer at the time of diagnosis, converted to negative nodes through NACT is debatable. This study evaluates the effectiveness, safety, and outcomes of SLNB in post-NACT breast cancer patients, while also examining the impact of NACT on tumor downstaging.

Materials and Methods: This prospective study involved 21 females with invasive breast carcinoma (ages 30-72) who underwent SLNB after NACT between January’2022 to September’2024 at AIIMS, Rishikesh. Tumor characteristics, including receptor status (ER, PR, Her2neu) and Ki67 index, were recorded before and after chemotherapy. SLNB was performed using lymphoscintigraphy with SPECT/CT and intra-operative gamma probe localization, employing peri-areolar and intra-tumoral injections of 1 mCi of 99mTc-filtered sulphur-colloid and methylene-blue dye to identify SLNs. Intraoperative frozen section analysis determined the need for ALND in metastatic cases, and outcomes like detection rates, tumor response, and post-operative morbidity were documented.

Results: SLNs were successfully identified in 20 out of 21 cases, achieving a 95% detection rate with SPECT/CT, 95.2% with the gamma probe and 85.7% with methylene blue dye. Tumor downstaging following NACT was observed in 18 breast tumors on imaging (81.8%), with 11 tumors (50%) achieving a complete pathological response (pCR). Intraoperative frozen section revealed SLN metastasis in 3/21 (14.3%) patients, prompting a change in management to ALND. Final histopathology evaluation indicated that 2/21 (9.5%) patients had evidence of nodal metastasis. Postoperative complications were minimal, with 2/21 (9.5%) patients developed mild lymphedema & 1 patient (4.8%) succumbing to distant metastasis.

Conclusions and References: Current prospective study shows that lymphatic mapping with SLNB, using SPECT-CT, Gamma Probe & dual-tracer technique, is feasible, safe and effective method for axillary staging in post-NACT breast cancer patients. It accurately identifies SLNs, serves as an effective tool for selecting minimally-invasive surgical techniques, avoiding unnecessary ALND, therefore not only reducing surgical morbidity, but also aid in guiding postoperative axillary irradiation approaches. These results support SLNB as a standard approach for post-NACT group, though further research with larger patient cohort is needed to confirm and refine treatment protocols.

Abstract ID: 127: Design, in silico studies, synthesis, cold-labeling and bio-evaluation of novel biscyclam-triazole based ligand: A novel PET theranostic agent targeting CXCR4

Deepika Sharma, Shubhra Chaturvedi, Vinod P. Sing, Anil Kumar Mishra

Institute of Nuclear Medicine and Allied Sciences, DRDO, Delhi, India

Introduction: C−X−C motif chemokine receptor 4 (CXCR4) is among the most promising target for therapeutics. Over 67% of the 19.2 million cancer cases diagnosed in 2020 were CXCR4 related, indicating CXCR4 is a crucial target for developing imaging agents and anticancer drugs. Belonging to the G-coupled protein receptor family, Chemokine receptors are not only expressed on malignant tumors but can also be potential theranostic targets for inflammatory diseases and neurodegenerative diseases. The novelty of this work is the introduction of triazole linkage using Click Chemistry and further incorporating oxo functionality. The bis cyclam scaffold, known for its CXCR4 affinity and strong coordination with metal ions, was coupled with a triazole moiety to enhance radiolabeling potential. This abstract presents a comprehensive overview of developing novel bis cyclam-triazole-based ligand as a PET theranostic agent targeting CXCR4.

Materials and Methods: The design and development of the radioligand was initiated through computational studies, utilizing molecular docking software Autodock, Autodock Vina, Discovery Studio and GROMACS to predict the binding interactions. The synthesis of the novel radioligand was achieved through a multi-step synthetic route, incorporating click chemistry for the triazole linkage and coldlabeling with CuCl2. The synthesis involved the formations of the following intermediates and the respective final molecule: a) Azide-malonate b) Cyclam-azide c) Alkyne-malonate d) Cyclam-alkyne e) Biscyclam-triazole. Characterization of the intermediates and the final compound was done using 1H NMR, 13C NMR, and HR-MS. The cold-labelling was done using CuCl2 and the complex was characterized after purification. The MTT assay and Hemolysis was performed to assess the bio-compatibility of the synthesized ligand. The physicochemical characterization included the binding affinity to determine the specific binding towards CXCR4 receptor.

Results: The quantitative yield of the final ligand was obtained 70%, and the HR-MS peak at m/z (M+H)- 551.3534 confirmed the formation of ligand. The ligand has shown high affinity toward the CXCR4 with a G- score of -7.6, indicating an excellent binding affinity. Non-toxicity of the ligand was established by less than 85% HEK cytotoxicity when incubated with 1 µM for 48 h.

Conclusions and References : The Novel ligand Biscyclam-Triazole targeting CXCR4 was synthesized successfully. The experimental work confirmed the findings of theoretical studies. The work will establish its potential application as a highly targeted PET theranostic agent for the CXCR4 receptor.

Abstract ID: 139: 68Ga-Pentixafor PET-CT in non-small cell lung cancer: Comparison with 18F-FDG PET-CT – A pilot study

Ragire Sainath, Gopinathraj Gunasekaran, Harinee Ganesan, Vignesh Hariharan, Vasanth Madivanane, Dhanapathi Halanaik

Department of Nuclear Medicine, JIPMER, Puducherry, India

Introduction: Lung cancer is one of the leading cause of cancer deaths, primarily non-small cell lung cancer (NSCLC). Accurate staging is critical for treatment planning and outcome prediction. Although 18F-FDG PET-CT is routinely used for staging, it has significant drawbacks. CXCR4 based cyclic pentapeptide Pentixafor (68Ga-Pentixafor PET-CT) imaging could be a potential modality for staging of NSCLC. This study aims to compare 68Ga-Pentixafor PET-CT and 18F-FDG PET-CT in evaluation of NSCLC.

Materials and Methods: This single-center ongoing study recruited 17 newly diagnosed, treatment-naive NSCLC patients who underwent both 68Ga-Pentixafor PET-CT and 18F-FDG PET-CT imaging within two weeks for baseline metastatic evaluation. The primary lesions, lymph nodes, and distant metastases between the two scans were assessed and compared. The level of agreement in lesion detection and semi-quantitative parameters analysis (SUVmax based on body surface area and TBRmax ratio) was done using Bland-Altman plot and Paired t-test.

Results: Among the 17 participants (mean age 59.05±12.26, 14 male, 3 female), the agreement in lesion detection between the two scans was 88.24%. 18F-FDG PET-CT detected more metastases in lymph nodes (136 vs 127), bone (59 vs 12) and lung (7 vs 4), with equal numbers of lesions in primary (17), adrenal (4), and brain (16) compared to 68Ga-Pentixafor PET-CT. 18F-FDG showed higher SUVmax in primary lesions (p=0.0003), lung metastases (p=0.0077) and bone metastases (p=0.00), with no significant difference in lymph nodes (p=0.3612) and adrenal lesions (p>0.05). TBRmax was significantly higher in primary lesions (p=0.0004) with 18F-FDG. In per patient analysis, almost all patients showed concordance except for skeletal metastases, where 18F-FDG PET-CT identified positivity in 6 patients compared to 3 with 68Ga-Pentixafor PET-CT.

Conclusions and References: 68Ga-Pentixafor PET-CT was concordant with 18F-FDG PET-CT in detecting primary and most metastatic lesions in NSCLC patients, except for skeletal metastases. 18F-FDG showed better results considering the SUVmax in almost all the lesions. However, 68Ga-Pentixafor PET-CT demonstrates higher sensitivity for detecting brain metastases due to higher background in 18F-FDG PET-CT. Additionally, 68Ga-Pentixafor offers advantages such as therapeutic potential, better radiotracer availability with on-site generators, and minimal patient preparation, enhancing clinical flexibility.

Abstract ID: 169: Role of Gallium 68 (Ga68) pentixafor PET-CT in the management of patients with hyperaldosteronism – Our experience

Saumya Sara Sunny, Julie Hephzibah¹, David Mathew¹, Justin Benjamin¹, Junita John¹, Anish Jacob²

Christian Medical College, Departments of ¹Nuclear Medicine and ²Endocrine Surgery, Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Adrenocortical adenomas (ACA) account for 36%–94% of adrenal incidentalomas. The functional ACAs are associated with increased morbidity and require adrenalectomy, whereas active surveillance is recommended for non-functional ACA/ adrenal hyperplasia. The diagnosis and lateralisation of these lesions is a diagnostic challenge. The current modality for confirmation is Adrenal venous sampling, a technically complicated procedure with highly variable success rates. (Ga68)-Pentixafor (68Ga-CPCR4), is a CXCR4 (C-X-C motif chemokine receptor 4)-specific PET tracer, may be effective for the evaluation of the functional lateralization of adrenal lesions and identification of functional adrenocortical adenomas.

Aim: To assess the utility of Ga68 Pentixafor PET-CT imaging in the diagnosis and management of patients with primary hyperaldosteronism.

Materials and Methods: Retrospective analysis of patients who underwent Ga68 Pentixafor PET-CT from July 2023 to September 2024. The clinical details at presentation, biochemical parameters, other cross sectional imaging findings, management was recorded for each patient. These were correlated with findings on the PET CT scan.

Results: Of the total of 7117 PET CT studies done, 9 patients (6 M/2 F, age range: 22-60 years) were included in the study. All of them presented with features of hypertension and biochemical confirmation of primary hyper-aldosteronism. Avidity in adrenals was noted in 6/9 patients, of which 1/6 patient had equal uptake in both adrenals and was advised medical management, while lateralisation (preferentially increased uptake in either of the glands) was possible in 5/6 of them. Among these 5 patients, one (1/5) had medical management. Only one (1/5) had an adrenalectomy and biopsy confirmed an adrenocortical adenoma. Three (3/5) of them are planned for surgical excision of the lateralised gland. Non-avidity in adrenal glands (adrenal hyperplasia) were noted in 3/9 patients and all of them had medical management with anti-hypertensives and Spironolactone. Overall, three of them had come for follow up after 4-6 months and had achieved symptomatic remission. The other patients are due for follow up in the upcoming months.

Conclusions and References: Ga68 Pentixafor PET-CT is a useful modality in planning the management of patients with primary hyperaldosteronism. It not only aids in the diagnosis and lateralisation of functional ACAs, but also differentiates adenomas from hyperplasia. This obviates the need for the invasive and expensive procedure of adrenal venous sampling and guides clinicians in deciding on medical versus surgical management.

Abstract ID: 70: To study the efficacy and safety of Lu177-EDTMP therapy for bone pain palliation in cancer patients with multiple skeletal metastasis

K. Vidhya, Vandana K. Dhingra, Meena Negi

Department of Nuclear Medicine, AIIMS, Rishikesh, Uttarakhand, India

Introduction: Metastatic bone pain (MBP) is a common issue among cancer patients, impacting their quality of life. Traditional treatments like chemotherapy and radiotherapy are come with lots of side effects. Radionuclide therapy, specifically Lutetium-177 (Lu-177) labelled with EDTMP, offers targeted radiation to MBP sites, improving mobility and reducing dependence on analgesics. However, limited research exists on Lu-177 EDTMP, particularly in India.

Aims: This study aims to evaluate the efficacy and safety of bone pain palliation in view of any toxicity effects using Lu177 EDTMP in cancer patients with multiple skeletal metastasis.

Materials and Methods: Experimental study single arm- 18 months durations. Patients diagnosed with cancer with bone scan done in Dept of Nuclear Medicine showing multiple skeletal metastasis with metastatic bone pain in between 1st June 2023 to 14 October 2024.

Results: A total of 7 patients were included in this study. Mean age distribution was around 60.4 yrs. All patients underwent a bone scan to confirm and localise multiple metastasis, which were then confirmed by physical examination to be corresponding to sites of pain. Patients initial type of analgesia, requirement and dose were noted. A significant reduction of pain score was noted in all patients. The initial mean pain score was 8.31, which dropped to 6.57, 3.57, 2.85, 3.14 and 3.71 in 1 week, 2 week and 1 month. 2 months and 3 months respectively. Scans acquired at 3-4 days compared to 1 day or 1 week showed good scan image quality for biodistribution. The mean karnofsky performance scores initially were 64.28 which improved to 87.14 after 4 wks. 1 patient experienced grade CTCAE grade 4 adverse effect in the form of anaemia, neutropenia and thrombocytopenia which was treated with blood transfusion and GM-CSF injections which in follow-up dropped to grade 1 in 2 weeks’ time. EORTC C30 quality of life was calculated using questionnaire after acquiring permission for using the tool in our study. The mean scores for QoL initially at baseline were 41.38% which improved to 70.71% at 1 month. Mobility scores at baseline were also calculated using Palmer Parker mobility scoring scale in which mean score was found to be 2.71 which increased to 6.14 at 1 month after therapy.

Conclusions and References: Cancer-related metastatic bone pain especially when resistant to opioids. Radiopharmaceuticals like Lutetium-177 (Lu-177) EDTMP offer targeted pain relief, longer duration, and improved quality of life. Despite mild hematological toxicity, Lu-177 is cost-effective and accessible, with minimal side effects observed in nearly all patients.

Abstract ID: 119: PSMA theranostics in high-grade gliomas – Augmenting the nuclear medicine arsenal

A. R. Vishnu, Nishikant A. Damle, G B Priyanka, Chandrasekar Bal, Madhavi Tripathi, K. P. Haresh, Subhash Gupta, Vivek Tandon, Amandeep Kumar, Sacchidanand Jee Bharati

All India Institute of Medical Sciences, New Delhi, India

Introduction: High-grade gliomas (HGG), including anaplastic astrocytomas and glioblastomas, are characterized by a high recurrence rate despite gross tumor resection and radiotherapy. Prostate-specific membrane antigen (PSMA) has recently emerged as a potential target in various malignancies beyond prostate cancer, including HGG. This study aims to evaluate the role of PSMA as a theragnostic target in the management of recurrent high-grade gliomas.

Materials and Methods: In this prospective study, we recruited patients with suspected recurrent high-grade gliomas following surgery and chemoradiotherapy. Ga68 PSMA 11 PET/CT imaging was performed 60 mins after injection (WB plus spot view brain), and its uptake was recorded. Lesions with PSMA uptake greater than 1.5 times that of the liver were selected for a tumor retention scan using a low-dose Lu177 PSMA 617 scan.

Results: Among the 14 patients recruited 9 males and 4 females, with a median age of 43 (age ranging from 31 to 69 years), 12 showed tracer uptake in the lesions seen on CT, while two patients did not reveal tracer uptake. A five-point Likert scale was used to assess PSMA uptake, with scores assigned as follows: 1 indicating no uptake, 2 indicating uptake less than the liver, 3 indicating uptake equal to the liver, 4 more than liver but less than parotid, and 5 indicating uptake equal to or greater than the parotid gland. Among the 12 patients, 9 (64.2%) had a score ≥4, while 3 (21.4%) had a score of 3. Based on PSMA uptake scores of 4 or higher and the ECOG performance scale, five of these patients underwent low-dose Lu177 PSMA-617 (5-7 mCi) scans at multiple time points (at least three) over 8 days. PSMA retention in the tumor was visualized in all five patients up to the last image with a progressive increase in tumor-to-liver and tumor-to-parotid ratio, highlighting its potential for retention in recurrent lesions and delivering targeted radiation to the tumor.

Conclusions and References: Lu177-PSMA therapy may be a feasible option to treat recurrent HGGs, and early results from our study show a favorable pattern of uptake and tumor retention of the PSMA ligand in imaging and retention studies respectively.

Abstract ID: 130: I-131 mIBG therapy superior to chemotherapy in high-risk neuroblastoma: A case report supporting early adoption

Vempa Satish, A. V. S. Anil Kumar, M. G. Vishnoi, Vaibhav Jain, J. S. Arora

Army Hospital Research and Referral, Delhi, India

Introduction: This case report aimed to evaluate the potential benefit of incorporating I-131 mIBG (meta Iodobenzylguanidine) therapy earlier in the treatment of high-risk neuroblastoma. By comparing the clinical outcomes of chemotherapy-induced stable disease with the near-complete response achieved through mIBG therapy, the report advocates for its consideration as a first-line treatment in mIBG-avid neuroblastoma.

Materials and Methods: A 6-year-old boy who presented with bilateral neck swelling, FNAC revealed metastatic small round blue cell tumor, FDG PET/CT revealed low grade FDG avid left cervical lymph nodes and lytic, sclerotic & marrow-based lesions and later diagnosed as a case of high-risk neuroblastoma, Initial mIBG scan revealed a Curie score of 20. Initially treated using the RAPID COJEC protocol, comprising Vincristine, Carboplatin, and Etoposide followed by two cycles of TVD (Topotecan, Vincristine, Doxorubicin). Post 2 lines of chemotherapy, diagnostic mIBG scan showed stable disease, indicating limited response to chemotherapy. Given this suboptimal response, the patient was referred for third-line therapy (I-131 mIBG). Two cycles of mIBG (200 mCi each) were administered within 12 weeks. Post-therapy mIBG scan shows a near-complete response. In view of near complete response he underwent autologous stem cell transplantation (ASCT) and was put on 13-cis-retinoic acid (isotretinoin) maintenance for consolidation.

Results: Following eight cycles of RAPID COJEC and two cycles of TVD, the I-131 mIBG scan revealed stable disease, reflecting limited efficacy of the chemotherapy regimen. In contrast, after two cycles of I-131 mIBG therapy there was near-complete response, demonstrating significant response to targeted therapy. 131- ImIBG therapy was well tolerated & showed no evidence of hematological or renal derangement. Subsequently the patient underwent ASCT (Autologous stem cell transplant). Nevertheless, the significant improvement observed with mIBG therapy compared to chemotherapy was notable.

Conclusions and References: This case report supports the potential superiority of I-131 mIBG therapy over conventional chemotherapy in controlling high-risk neuroblastoma. While chemotherapy only resulted in stable disease, mIBG therapy achieved a near-complete response. These findings suggest that earlier integration of mIBG therapy in treatment regimens may improve clinical outcomes, especially in mIBG-avid metastatic disease. Further studies are warranted to assess the role of mIBG as a first-line treatment option in high-risk neuroblastoma.

Abstract ID: 189: Comparative evaluation of renal parameters with E-GFR, Renogram, creatinine clearance (M-GFR), before and after lu177 based therapy

S. Asfaq Ahmed, R. Krishna Kumar, G. K. Rangarajan, N. Anandhi, Rajeevalochana Parthasarathy, Sanjeev Nair

Cancer Institute, Chennai, Tamil Nadu, India

Introduction: In renal assessment preparation for PRRT and PSMA ligand therapy. We have compared the values with three methods of E-GFR, creatinine clearance and Renogram. We have repeated all the three techniques after two fractions of PRRT and PSMA with clinical evaluation of the patients also done. The values revealed almost stable parameters. Measured GFR (creatinine clearance) is taken as gold standard for comparison of other values.

Materials and Methods: 30 patients who have undergone lu177 based therapy, we were assessed RFT (renal function test) by the three methods. All values were within normal limits. Renogram done with tc99m- DTPA, measured GFR (i.e. Creatinine clearance done with urine collected over 24 hrs and assessed), E-GFR calculated with CKD-EPI creatinine formula (2021). After two courses of lu177 based therapy (200 mci *2 courses), all the three tests were repeated. GFR were stable and the RFT parameters were still under within normal limits.

Results: E-GFR values ranged from 72 to 135 ml/min/1.73 m2, Renogram GFR ranged from 43.1 to 130 ml/min, Creatinine clearance ranged from 45.2 to 166 ml/min, On repetition also all the three values were within normal limits.

Conclusions and References: The three methods, we have used are very reliable parameter for nephron assessment before lu177 based therapy. We can safely administer lu177 based therapy based at the values.

Abstract ID: 9: Retrospective evaluation of nucleophilic radiosynthesis of [18F]-L-FDOPA using an automated chemistry module

Raviteja Nanabala, P. K. Arun, K. Anees Muhammed, Dilshad Kottuparamban, Junais Pokkat, Shinooj Maniyoth Kuni, Thomas George, Vishnunath Pazhakkal, Maroor Raghavan, Ambikalamajan Pillai

Molecular Cyclotrons Pvt. Ltd., Ernakulam, Kerala, India

Introduction: [18F]-L-FDOPA (FDOPA) finds application for neurological and oncological PET studies. FDOPA is prepared by both electrophilic and nucleophilic routes, however, the latter route is preferred as the product formed has higher specific activity. FDOPA is synthesized through multiple nucleophilic synthesis routes and the radiochemical yields vary significantly depending on the synthesis route followed.^[1,2] Producing higher quantities of FDOPA is crucial as there is good demand for this tracer. In this study, we present a retrospective analysis of 17 batches of FDOPA produced using a synthesis route adapted in the Trasis module.

Materials and Methods: No-carrier-added fluorine-18 was produced using an 11 MeV Siemens cyclotron. FDOPA was synthesized using Trasis with cassettes supplied by Trasis. This nucleophilic synthetic route has five steps: precursor (nitroveratraldehyde) labeling, reduction, iodination, stereoselective alkylation with a Schiff base and acidic hydrolysis. The product is purified by semipreparative HPLC. Radiochemical purity was assessed using an Eckert & Ziegler TLC scanner.

Results: A total of 17 batches of FDOPA were produced using Trasis module. The radiochemical yields were 33 ± 6% (non-decay corrected) and 55 ± 10% (decay corrected) for n=15 which are higher than the reported methods. Two batch failures were occurred. Fluorine-18 labeled precursor yield was 71 ± 12% (n=17), which is higher than the other reported automated radiosynthesis. This is an important aspect for the high radiochemical yields. The radiochemical purity of FDOPA was consistently above 95% for all the batches. pH of the final product was 4-4.5. Bacterial endotoxin level was < 2 EU/mL. All the batches passed the sterility tests.

Conclusions and References: FDOPA could be prepared in high radiochemical yields and purity. The retrospective analysis of 17 batches of automated FDOPA production provides and insight to the different synthesis steps and the results are useful for improving FDOPA radiosynthesis. This analysis can help radiochemists to refine and enhance radiochemical yields to accommodate a larger demand of this product.

Abstract ID: 78: FDG-PET/CT guided robotic arm-assisted, percutaneous core-needle liver biopsies: including patients with pyrexia of unknown origin

Bhabani Shankar Nayak, Sivasankar Kanankulam Velliangiri, Geetanjali Arora, Vrati Jain, Apoorva Tyagi, Manish Soneja, Madhavi Tripathi, C. S. Bal

All India Institute of Medical Sciences, New Delhi, India

Introduction: In the absence of potential diagnostic clues (PDCs) F-18 Fluordeoxyglucose Positron Emission tomography/computed tomography (FDG-PET) is the imaging technique of first choice in pyrexia of unknown origin (PUO). Biopsy of FDG avid lesions can provide definitive histopathological evidence, essential for accurate diagnosis and guiding appropriate therapy. We sought to evaluate the feasibility, diagnostic success rate and safety of image guided (FDG-PET) percutaneous core-needle biopsies performed by robotic arm assisted spatial positioning for liver lesions in patients with PUO.

Materials and Methods: This prospective, interventional study included PUO patients who were referred for FDG PET/CT and were found to have FDG-avid liver lesions amenable for biopsy. Informed and written consent was taken from each patient and FDG was injected. Single bed acquisition of both CT and PET was followed by transfer of the images to the robotic arm assisted needle positioning system (Maxio, Perfint Healthcare), where they were used for defining the trajectory to the FDG-avid target lesion along with the entry point. The biopsy needle was navigated to the target lesion along the planned path followed by a check CT to confirm needle positioning. Atleast three cores were sampled from the lesion and fixed in both formalin (10%) and normal saline before sending them for histopathology and PCR. The histopathology reports were assessed for final diagnosis.

Results: A total of 10 patients with FDG avid liver lesions (6 males; 4 females) were included. The mean injected activity was 3.7±1.9 mCi. We obtained good cores from all target lesions in one attempt. Minimal bleeding during the biopsy was seen in 1 patient but this was not associated with hematoma formation. The detection rate was 90 %. Results of FDG PET guided biopsy from liver lesions in 10 patients - Infection (Tuberculosis = 5, Abscess = 1), Malignancy (Cholangiocarcinoma = 1, Hodgkin lymphoma = 1), Metastases (Neuroendocrine tumor = 1), (Negative/ Indeterminate = 1 patient).

Conclusions and References: FDG-PET guided percutaneous liver biopsies targeting metabolically active lesions performed by robotic arm assisted needle positioning is technically feasible, safe, and effective and has potential utility in identifying the etiology of PUO.

Abstract ID: 131: Diagnostic performance of real-time robotic arm assisted 18F-FDG PET/CT guided percutaneous metabolic biopsies in patients under the age group of 18 years

M. Gowtham, Rajender Kumar, Harmandeep Singh, Bhagwant Rai Mittal

Department of Nuclear Medicine, PGIMER, Chandigarh, India

Introduction: This study aimed to comprehensively evaluate the safety and diagnostic yield of positron emission tomography/computed tomography (PET/CT)-guided biopsy procedures in patients under 18 years of age.

Aim: To evaluate the feasibility and diagnostic performance of automated robotic arm (ARA) assisted 18F-FDG-PET/CT-guided sampling of patients under 18 years of age.

Materials and Methods: We conducted a retrospective analysis of all PET/CT-guided biopsy procedures performed on patients under 18 years of age at our tertiary care center between January 1, 2022, and September 30, 2024. PET/CT and biopsy protocol: All procedures were performed using a hybrid PET/CT scanner. Patients fasted for at least 6 hours prior to the procedure. F-18 FDG was administered intravenously and regional PET/CT scan of the region of interest was obtained after 60 minutes of injection. PET images were acquired for 2-3 bed positions (2 minutes per bed position) and reconstructed. The biopsies were done under local anaesthesia and ARA-assistance. Real-time samples were retrieved after confirming the position of needle-tip within the target lesion with PET/CT. To check the diagnostic performance of the procedure, histopathology reports were reviewed. Negative results were confirmed with clinical or imaging follow-up.

Results: The lesions were successfully targeted in all patients and yielded a pathological diagnosis. The mean age of 30 participants enrolled in the study is 15.57 + 2.25 years and 20 (66.7%) were males. Four out of 30 (86.6%) patients showed negative or descriptive findings in PET/CT guided biopsy. Biopsy targets included Lymph Node (n=8), bone (n=7), lung (n=7), liver (n=3), mediastinum (n=2) and paravertebral lesions (n=3). Lesion characteristics such as size, depth, and anatomical location were recorded. Out of 26 positive cases, the findings in 14 (53.84%) participants were benign and 12 (46.16%) were malignant. There were 6 participants who reported negative in previous CT guided biopsy and were positive in PET/CT guided biopsy in our study. No life threatening immediate or delayed complications were observed post procedure.

Conclusions and References: Percutaneous metabolic sampling of paediatric patients under the age group of 18 years with ARA-assistance is a technically feasible, safe and accurate method for pathological diagnosis with high diagnostic performance. PET/CT combines functional (PET) and anatomical (CT) imaging, potentially offering more precise localization of metabolically active lesions. This can be especially valuable in small or difficult-to-access lesions, heterogeneous tumors where the most active area needs to be sampled, cases where previous CT or USG guided biopsies were non-diagnostic.

Abstract ID: 179: Robot-guided PSMA targeted percutaneous trans-gluteal prostate gland biopsy: Yield and complication of procedure in a tertiary care centre in North India

Aftab Hasan Nazar, Manish Ora, Sanjay Surekha, Sanjay Gambhir

Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Introduction: Transrectal ultrasound (TRUS) prostate biopsy has been a standard approach for prostate cancer (PCa). However, TRUS is associated with many risks. Sepsis is most dreaded complication of TRUS biopsy. Reason for infection is inoculation of rectal flora into prostate by biopsy needle as it pass through rectum. Another disadvantage of TRUS biopsy is lack of tumor targeting. PSMA PET/CT is commonly used in management of PCa. We did robotic-guided percutaneous trans-gluteal route biopsy to target PSMA expressing lesions to counter these two disadvantages.

Materials and Methods: Patients suspected to have PCa were referred for PSMA PET/CT. Patient were categorised into two groups, one who underwent prior TRUS guided biopsy and who were TRUS naive. Patients were explained possible complication of procedure. A prostatic lesion with maximum PSMA expression was identified on Axial PET/CT images. The lesion was marked as a target and co-axial biopsy needle is inserted through percutaneous trans gluteal route under robotic guidance. Procedure was performed under local anaesthesia. Histopathological reports were checked in Hospital information system. Patient were contacted telephonically after one week and asked questions about complication.

Results: Between September 2021 to August 2024, total of 54 patients underwent biopsies. The mean age of the patient was 66.0 ± 8.3 (50- 83) years. 15 patients had prior TRUS guided biopsy with negative results. 19 patients has S. PSA of more than 100 ng/mL. Mean PSA of the rest of the patients was 24.77 (±20.57) ng/mL. 21 patients had PSA of less than 20 ng/mL. Final HPE was Adenocarcinoma in the 30 patients. Inadequate samples were noted in the three patients. Prostatitis/BPH seen in four patients. There was no malignancy in 16 patients (all with PSA < 20 ng/mL). Procedure was aborted in one due to uncooperative patient. 15 patients who were negative on TRUS guided biopsy, five came positive in guided biopsy. Biopsy was uneventful in 77% (42) of the patient. 11% (6) Patients had self-limiting mild transient hematuria after biopsy, 7% (4) patients experienced mild pain while micturition for one day and 1 patient complain acute urinary retention for 6 hours and one experienced hematospermia. No patient had an infection or pain post-procedure.

Conclusions and References: Robot-guided PSMA targeted percutaneous trans-gluteal prostate gland biopsy is a safe and reasonable approach. It could be helpful in patients with previously failed biopsies. It is safe with relatively no severe complications. The positive yield could improve after a lag phase.

Abstract ID: 15: Optimization of ⁶⁸Gallium-exendin labeling: A novel approach for insulinoma imaging

Ritwik Sinha, Arvind Suresh, Srikanth Saminathan, Jayprakash, Ajay Kumar, Ravi Kumar Chauhan, Manoj Chauhan, Uddeshya Narayan Jha, Arvind Gupta, Bhola Kumar

Department of Nuclear Medicine, Homi Bhabha Cancer Hospital and Mahamana Pandit Madan Mohan Malviya Cancer Centre (A Unit of Tata Memorial Centre), Varanasi, Uttar Pradesh, India

Introduction: Insulinoma is a rare, typically benign tumor of the pancreas that originates from insulin-producing beta cells. This tumor in pancreas results in excessive secretion of insulin, which leads to hypoglycemic episodes. Weakness, dizziness, sweating, confusion, and in severe cases, unconsciousness or seizures are some common symptoms of insulinoma. Diagnosis generally involves blood tests to confirm hypoglycemia during symptomatic episodes, followed by imaging techniques such as MRI, CT scans, or endoscopic ultrasound to locate the tumor. However, these methods can have limitations in detecting small or atypical insulinomas. Recently, ⁶⁸Gallium (⁶⁸Ga) Exendin PET/CT has gained significance in the detection of insulinomas, especially for small or elusive tumors that may not be visible with conventional imaging methods. This scan utilizes a radiotracer that binds to the GLP-1 receptor (GLP-1R), offering highly sensitive and specific visualization of the tumor. Glucagon-like peptide-1 (GLP-1) is the natural ligand for GLP-1R and degrades rapidly in the blood. The use of this imaging technique enhances insulinoma localization, aiding in precise surgical planning and increasing the likelihood of successful curative treatment.

Materials and Methods: The radiosynthesis of ⁶⁸Ga-labeled Exendin-4-Lys⁴⁰-Ahx-DOTA peptide was carried out in a hospital-based radiopharmacy using a 68Ge/⁶⁸Ga generator from Isotope Technologies Garching, Germany. A 100 µg quantity of Exendin-4 peptide was procured from Peptide Specialty Laboratories GmbH, Germany. The production process involved reacting 100 µg of Exendin-4 peptide in 1.1 ml of 0.023 g sodium acetate buffer with 4 ml of ⁶⁸GaCl (Gallium Chloride) in 0.05M HCl for 30 minutes at 85°C. This was followed by purification using a Waters Sep-Pak tC18 cartridge, and the product was collected in a product vial. The tC18 cartridge was pre-rinsed with 100% ethanol, followed by ultra-pure water. The final product was passed through the tC18 cartridge for purification. The quality control of the final product was conducted using iTLC with sodium citrate as the mobile phase. Good Manufacturing Practices (GMP) standards were performed during the entire process.

Results: The radiochemical purity (RCP) of the final ⁶⁸Ga-Exendin product was found to be greater than 95%.

Conclusions and References: The in-house labeling of ⁶⁸Ga-Exendin-4 was successfully optimized, yielding a radiochemical purity of over 95%. This demonstrates the potential of ⁶⁸Ga-Exendin-4 as a promising radiopharmaceutical for insulinoma imaging, particularly in cases where tumors are small or difficult to detect through conventional imaging methods. This high RCP also ensures the safety and effectiveness of the radiopharmaceutical for clinical use.

Abstract ID: 16: Optimization of ⁶⁸Gallium-exendin labeling: A novel approach for insulinoma imaging

Ritwik Sinha, Arvind Suresh, Srikanth Saminathan, Jayprakash, Ajay Kumar, Ravi Kumar Chauhan, Manoj Chauhan, Uddeshya Narayan Jha, Arvind Gupta, Bhola Kumar

Tata Memorial Centre, Varanasi, Uttar Pradesh, India

Introduction: Insulinoma is a rare, typically benign tumor of the pancreas that originates from insulin-producing beta cells. This tumor in pancreas results in excessive secretion of insulin, which leads to hypoglycemic episodes. Weakness, dizziness, sweating, confusion, and in severe cases, unconsciousness or seizures are some common symptoms of insulinoma. Diagnosis generally involves blood tests to confirm hypoglycemia during symptomatic episodes, followed by imaging techniques such as MRI, CT scans, or endoscopic ultrasound to locate the tumor. However, these methods can have limitations in detecting small or atypical insulinomas. Recently, ⁶⁸Gallium (⁶⁸Ga) Exendin PET/CT has gained significance in the detection of insulinomas, especially for small or elusive tumors that may not be visible with conventional imaging methods. This scan utilizes a radiotracer that binds to the GLP-1 receptor (GLP-1R), offering highly sensitive and specific visualization of the tumor. Glucagon-like peptide-1 (GLP-1) is the natural ligand for GLP-1R and degrades rapidly in the blood. The use of this imaging technique enhances insulinoma localization, aiding in precise surgical planning and increasing the likelihood of successful curative treatment.

Materials and Methods: The radiosynthesis of ⁶⁸Ga-labeled Exendin-4-Lys⁴⁰-Ahx-DOTA peptide was carried out in a hospital-based radiopharmacy using a 68Ge/⁶⁸Ga generator from Isotope Technologies Garching, Germany. A 100 µg quantity of Exendin-4 peptide was procured from Peptide Specialty Laboratories GmbH, Germany. The production process involved reacting 100 µg of Exendin-4 peptide in 1.1 ml of 0.023 g sodium acetate buffer with 4 ml of ⁶⁸GaCl (Gallium Chloride) in 0.05M HCl for 30 minutes at 85°C. This was followed by purification using a Waters Sep-Pak tC18 cartridge, and the product was collected in a product vial. The tC18 cartridge was pre-rinsed with 100% ethanol, followed by ultra-pure water. The final product was passed through the tC18 cartridge for purification. The quality control of the final product was conducted using iTLC with sodium citrate as the mobile phase. Good Manufacturing Practices (GMP) standards were performed during the entire process.

Results: The radiochemical purity (RCP) of the final ⁶⁸Ga-Exendin product was found to be greater than 95%.

Conclusions and References: The in-house labeling of ⁶⁸Ga-Exendin-4 was successfully optimized, yielding a radiochemical purity of over 95%. This demonstrates the potential of ⁶⁸Ga-Exendin-4 as a promising radiopharmaceutical for insulinoma imaging, particularly in cases where tumors are small or difficult to detect through conventional imaging methods. This high RCP also ensures the safety and effectiveness of the radiopharmaceutical for clinical use.

Abstract ID: 158: Comparison of radiochemical purity between thyroid uptake probe and sentinel probe

S. Saravana Kumar, K. K. Kamaleshwaran, E. Ramkumar, E. R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: The aim of study to compare the radiochemical purity between the sentinel probe and the thyroid uptake probe utilizing paper chromatography as the analytical method. Radiochemical purity (RCP) is defined as the fraction of total radioactivity present in the desired chemical form, which is crucial for the quality control of radiopharmaceuticals. Whatman paper (3) chromatography was employed to assess the radiochemical purity of a 99m -Tc radiopharmaceutical. The study aims to compare the variations in radiochemical purity between the thyroid uptake probe and the sentinel probe.

Materials and Methods: A small aliquot of the 20 samples of 99m –Tc labelled DMSA were spotted on Whatman paper (3). The spotted strip is dipped into an acetone in a test tube. During the chromatography process, paper act as a stationary phase and solvent act as a mobile phase. After some time, the solvent present in the mobile phase rises up in the strip. The paper is dried and cut into two equal segments. The radioactivity of both the segments is measured in both the thyroid uptake probe (capintec, inc) and the sentinel probe (europrobe3.2 module). Counts were noted.

Results: Among 20 experiments, the percentage of radiochemical purity detected by the sentinel probe is 96.7% and the percentage of radiochemical purity detected by thyroid uptake probe is 96.8%. No Statistical variations observed across the experiment.

Conclusions and References: The result showed that the values obtained from both probes were identical. So, both the thyroid uptake probe and the sentinel probe were efficient for calculation radiochemical purity.

Abstract ID: 166: Impact of hydration on NaI (Tl) crystal in gamma camera

Gauthamgopukumar, K. K. Kamaleshwaran, E. Ramkumar R. Radhakrishnan, F. R. Kingsley, R. V. Rithika, S. Arun Pandiyan

Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India

Introduction: Aim of this study is to see the impact of NaI (Tl) crystal hydration in quality of the image in gamma camera. The camera’s main component is a large crystal made of sodium iodide doped with thallium, which detects gamma rays. The crystals create flashes of light, converted into electrical signals by a photochromic lamp, which can reveal abnormalities or functional problems. Moisture of the crystals may cause tiny white or yellow spots. This may affect the quality of the images at the diagnostic level.

Materials and Methods: The calibration studies on uncollimated gamma cameras with a point source emitting Tc-99m in front of the detector were carried out on a daily basis. This tested the detectors’ intrinsic performance using three energy windows: on-peak at 140 keV and off-peak at 126 keV and 154 keV. The outcome contributes to optimizing the performance of equipment in nuclear medicine techniques. Results increase the accuracy and reliability of images in nuclear medicine procedures with the detection of Tc-99m radiation.

Results: The integral and Differential uniformity of both detector as mention below

The integral uniformity for the CFOV was found to be 1.935% while the integral uniformity for the UFOV was 2.26%. The differential uniformity for the CFOV was 1.755% while the differential uniformity for the UFOV was 1.59%.

Conclusions and References: Confirmation that the crystal is hydrated should be done by further images, obtained with an asymmetrically placed energy window. In the event hydration could be observed in images obtained using an asymmetric energy window, care must be taken with the gamma camera until the crystal was replaced.

Abstract ID: 199: Designing a customised phantom for volatile iodine 131 to calculate senstivity of gamma camera with high energy collimator

R. Angelin Christy

Christian Medical College, Vellore, Tamil Nadu, India

Introduction: Sensitivity is one of the important QC test in Nuclear Medicine that is done to see how sensitive the Gamma Camera to radiation. This test cannot be done using our manual method (petri dish) for high energy collimator as Iodine 131 is volatile. Hence, a simple phantom can be customized using saline packet to prevent escape of volatile iodine and to calculate sensitivity of gamma camera for high energy collimator.

Aim: To design a simple phantom using saline packet to prevent escape of volatile iodine and to calculate sensitivity of gamma camera for high energy collimator.

Materials and Methods: Empty 100 ml saline packet, 20 ml syringe and QC source of 131 Iodine. 100 ml of empty saline pack is constructed into a shape of rectangle (8 cm length and 9 cm breadth) with air and water, source of I131 was added to the rectangular saline packet, radioactivity used ranged from 150-200 µCi. QC procedure was done 10 times on the phantom. Image acquisition was done by keeping phantom at 10 cm distance from each detector and counts were acquired for 1 minute in a gamma camera (SIEMENS). Images from gamma camera were analysed by drawing region of interests (ROI) in phantom. Total counts in ROI of customized phantom were noted and sensitivity of gamma cameras were calculated and compared with manufacture’s assured values (136 cpm).

Results: From the above results, simple customized phantom values are remarkably close to the manufactures value. The time taken for constructing and customizing the phantom is 77 seconds, so the amount of exposure is also minimal. With our customized phantom, we can have a uniform mixing of the radioactive material and its closed unit which prevents contamination and prevent the volatile iodine from escaping.

From the above results, simple customized phantom values are remarkably close to the manufactures value. The time taken for constructing and customizing the phantom is 77 seconds, so the amount of exposure is also minimal. With our customized phantom, we can have a uniform mixing of the radioactive material and its closed unit which prevents contamination and prevent the volatile iodine from escaping.

Conclusion: Using this phantom, sensitivity test can be done regularly in all Nuclear Medicine setups without compromising on the clinical time of equipment and avoiding contamination of the detectors.

Abstract ID: 202: Optimization of peptide quantities to enhance synthesis yield and radiochemical purity of Ga-68 PSMA-11 for clinical applications

Srikanth Saminathan¹, Arvind Suresh^1,2, Ravi Chauhan^1,2, Bhola Kumar^1,2, Jay Prakash^1,2, Manoj Chauhan^1,2, Uddheshya Jha^1,2, Ritwik Sinha^1,2, Ajay Kumar^1,2, Arvind Gupta^1,2

¹Mahamana Pandit Madanmohan Malviya Cancer Centre and Homi Bhabha Cancer Hospital, Tata Memorial Centre, ²Homi Bhabha National Institute, Varanasi, Uttar Pradesh, India

Introduction: Prostate cancer (PCa) is the second most common cancer diagnosed in males worldwide. A critical biomarker in the diagnosis and management of PCa is prostate-specific membrane antigen (PSMA), a type II membrane glycoprotein found in high concentrations on prostate cancer cells. The use of Ga-68 PSMA-11 PET/CT scans has revolutionised the detection and staging of prostate cancer, demonstrating superior sensitivity and specificity compared to traditional imaging modalities. The escalating demand for [68Ga]-labelled peptides, with a specific focus on Ga-68 PSMA-11, while minimising the costs associated with their radiosynthesis. The objective of this study is optimising the quantity of standardised peptides utilised during the labelling process, aiming to maximise both yield and radiochemical purity (RCP).

Materials and Methods: PSMA-11 peptide (0.5 mg) was routinely fractionated into aliquots of approximately 16.6 µg as per the manufacturer’s (ITg, Germany) recommendations. For this study, the peptide was instead fractionated into aliquots ranging from 3 µg to 12 µg. Manual synthesis was performed using a standard dose of 10 mCi (370 MBq) of GaCl3, which was eluted from the generator with 4 mL of 0.05M HCl into the reaction vial. Each fractionated peptide aliquot (3-12 µg) was diluted in 900 µL of sodium acetate buffer and added to the reaction vial. The mixture was heated in a dry block heater at 95 °C for 15 minutes. Following synthesis, the reaction mixture was passed through a C-18 cartridge to trap the labelled Ga-68 PSMA-11, which was subsequently eluted using 3 mL of 50% ethanol. RCP and yield were quantified using an iTLC Scanner and through appropriate calculations.

Results: The RCP of the fractionated Ga-68 PSMA-11 was assessed, revealing values exceeding 93.10% ± 3.34% with peptide amounts above 6 µg, while RCP was measured at 86.26% ± 5.81% with 3-5 µg of peptide. The yield for each final product was calculated to be 98.65%.

Conclusions and References: The synthesis yield of Ga-68 PSMA-11 can vary based on the employed methodology but typically exceeds 80%. When employing more than 10 µg of peptide, the final product demonstrated an RCP greater than 96%. RCP increased with a higher number of Ga-68 PSMA-11 molecules synthesised, peaking at 10 µg of peptide. The importance of optimising peptide quantities to enhance the efficiency and cost-effectiveness of Ga-68 PSMA-11 synthesis.