Robotic Assistance in PET-CT-guided Lung Biopsies: Enhancing Accuracy and Clinical Outcomes

Introduction

Lung biopsies are essential for diagnosing lung masses, with techniques varying based on access route and diagnostic purpose. The Tru-cut biopsy technique is recognized for its safety, efficiency, and reliability. Positron emission tomography–computed tomography (PET-CT), particularly with robotic-assisted systems, has advanced oncological imaging, enhancing tumor localization and biopsy precision.

The advent of PET-CT has revolutionized oncological imaging by enhancing the precision of tumor localization and staging. When coupled with robotic-assisted systems, PET-CT-guided biopsies have the potential to significantly improve diagnostic accuracy by allowing precise needle positioning and real-time imaging feedback.

While PET-CT-guided biopsies show promise, questions remain about their advantages over conventional methods and the added value of robotic assistance. This study systematically evaluates the diagnostic utility and accuracy of PET-CT-guided robot-assisted biopsies versus CT-guided biopsies.

Moreover, the added value of robotic assistance in biopsy procedures, including the potential to reduce sampling errors and complications, has not been fully explored in clinical practice.

This study systematically evaluates the diagnostic utility and accuracy of PET-CT-guided robot-assisted biopsies versus CT-guided biopsies.

By examining this novel combination of technologies, the research will provide critical insights into the effectiveness, safety, and clinical impact of these procedures. This study seeks to fill the knowledge gap on whether PET-CT-guided, robot-assisted biopsies offer a significant advantage in terms of diagnostic yield, complication rates, and procedural efficiency, ultimately contributing to better clinical decision-making in lung cancer diagnosis.

Materials and Methods

The study involved 50 patients: 25 underwent PET-CT-guided robot-assisted biopsies, and 25 underwent conventional CT-guided biopsies. PET/CT-guided procedures used a GE Discovery 690 scanner with a ROBIO machine, integrating imaging data for real-time robotic navigation. Patients with prior PET/CT scans were noted, and the rationale for fluorodeoxyglucose (FDG) reinjection during biopsy is discussed in terms of lesion identification and procedural necessity, balancing radiation exposure risks for patients and physicians.

The PET-CT biopsy procedures were conducted using a 64-Slice GE Discovery 690 with time of flight for conducting ¹⁸F-FDG PET-CT scans and robot-assisted PET-CT-guided ROBIO machine for PET-CT image-guided biopsy procedures. Biopsies were performed utilizing an 18G and 17G semi-automatic needle with the coaxial technique and robot-assisted guidance of mapping the image-guided track, planned with target depth and orbital angle depending on the lesion location. Patient position was supine in 18 patients, lateral in two patients, and prone in five patients. The procedure begins with the acquisition of high-resolution PET-CT images, which helps identify suspicious lesions and enables proper staging. The imaging data are then integrated with the robotic system, providing real-time feedback and navigation during the biopsy procedure. This synergy allows for targeted biopsy sampling, reducing the likelihood of missing significant lesions and minimizing the number of biopsy cores needed [Figure 1a-d].

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Figure 1 The Robot assisted mapping technique to target metabolically active lesions in lung

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The above data were compared for accuracy with CT-guided biopsy procedures as a reference standard with the standard institutional protocol using a different set of 25 patients requiring lung biopsies [Figure 2a-m].

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Figure 2 PET CT imaging integrated with the robotic system compared for the accuracy with CT guided Biopsy procedures as a reference standard using a different set of 25 patients requiring lung biopsies

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Results

• PET-CT-guided biopsy:

  • Mean diagnostic accuracy: 97.62% (standard deviation [SD]: 0.7%)

  • Sensitivity: 81% for hypermetabolic regions

  • Complications: Low (no major events).

• CT-guided biopsy:

  • Mean diagnostic accuracy: 85% (SD: 5%)

  • Sensitivity: 79% for similar malignancies

  • Complications: Comparable to PET-CT-guided procedures.

Discussion

PET-CT-guided biopsy or fine-needle aspiration using automated robotic arm (ARA) integrated with a PET-CT scanner offers a unique and feasible approach. It is easy to perform and allows for precise sampling of viable tumor tissue. The ARA system enhances accuracy, precision, and user confidence during the procedure.[1]

Robotic arm-assisted FDG PET/CT-guided real-time bone biopsy is a feasible and safe procedure, offering a high diagnostic yield. It has demonstrated significant clinical impact, particularly in patients with minimal residual FDG uptake on end-of-treatment PET/CT and those with isolated suspected metastatic lesions.[2]

PET/CT-guided percutaneous bone biopsy is a safe and effective alternative to CT-guided biopsy, offering high diagnostic accuracy in evaluating hypermetabolic bone lesions for the diagnosis of bone tumors and tumor-like conditions.[3]

PET guidance enhances the diagnostic yield of image-guided procedures by directing needle insertion into the most viable areas of a lesion. This approach shows that metabolic biopsy is a practical, safe, and efficient method with strong diagnostic performance, potentially leading to an immediate impact on treatment decisions and patient care.[4]

FDG PET/CT guides the biopsy to the most metabolically active region of the lesion, reducing the likelihood of sampling errors from necrotic or fibrotic areas.[5]

In patients with multiple lesions, PET-CT scans help identify the most accessible site for biopsy. Targeting the most accessible lesion minimizes sampling errors and lowers the risk of complications associated with the procedure.[6]

The primary drawback of metabolic biopsy is the increased radiation exposure for both the patient and the operator. Patients undergoing whole-body PET-CT typically receive an average radiation dose ranging from 8 to 30 mSv, depending on the specifics of the procedure and the number of body regions scanned. The CT component generally accounts for 54%–81% of the total dose.[3]

There was no clear evidence that PET-CT was significantly superior to CT-guided biopsy alone, with a success rate only 3% higher in the PET-CT group. However, the small sample size and the 95% confidence interval indicate that the difference could range from 16% lower to 22% higher with PET-CT.[78]

There were no significant differences in diagnostic specimen retrieval or complication rates between PET/CT-guided and CT-guided biopsy procedures.[910]

Some limitations and challenges mentioned in the study:

• Sample nonrepresentativeness: Some biopsies resulted in nonrepresentative samples, leading to inconclusive diagnoses

• Missed diagnoses: Despite multiple attempts, a few cases of nonneoplastic/benign diseases were missed

• Complications: Although rare, there were instances of complications postprocedure

• Cost and accessibility: While generally affordable, the cost and accessibility of image-guided biopsy procedures can vary.

Conclusion

This study demonstrates that PET-CT-guided lung biopsies, particularly when robot-assisted, offer superior diagnostic accuracy (97.62%) compared to conventional CT-guided biopsies (85%). The higher precision of PET-CT-guided procedures, along with their low complication rates, makes them a valuable tool for detecting malignancies in lung lesions. By integrating high-resolution PET-CT imaging with robotic assistance, the procedure allows for more accurate needle positioning and reduces the likelihood of missed lesions.

While PET-CT-guided biopsies may involve higher costs and limited accessibility, their enhanced diagnostic yield and reduced need for repeat procedures highlight their potential in clinical practice. This technique holds promise for improving patient outcomes, particularly in complex cases. Further research with larger patient cohorts is recommended to validate these findings and explore broader clinical applications in lung cancer management.

This study supports the use of PET-CT-guided, robot-assisted biopsies for improved diagnostic outcomes. However, considerations of radiation exposure, cost, accessibility, and procedural learning curves are critical for broader clinical applications.