Fully integrated handheld gamma camera compared to conventional gamma camera for detection and localisation of sentinel lymph nodes in breast cancer

Aim/Introduction: Preoperative lymphoscintigraphy is the gold standard for sentinel lymph node biopsy (SLNB) in breast cancer (BC) patients. However, conventional gamma camera imaging is prone to operator variability and time consuming in the nuclear medicine department work$ow. This study aims to validate the performance of the Pocket Gamma CAM (PGC), a handheld gamma camera, in detecting and locating sentinel lymph nodes (SLNs) during the preoperative and intraoperative phases in BC patients compared to conventional gamma camera imaging. In addition, we evaluated the manoeuvrability and intrinsic instrument sensitivity of both devices. Materials and Methods: Adult female patients with histologically con!rmed BC candidates for surgery and SLNB were enrolled in this prospective open-label clinical trial. All patients underwent pre- and intra-operative assessment using both the PGC and conventional lymphoscintigraphy. The performance of the two devices was compared using the Poisson regression model for incidence rate ratios (IRRs). The intrinsic sensitivity of the devices was compared using the Wilcoxon Ranked Sign Test. The manoeuvrability of the devices was de!ned as low-moderate-high. Results: Sixty-eight patients (median age 50 years, BMI 21.4) were enrolled, including one patient with bilateral breast cancer who underwent two SLNBs. The PGC demonstrated superior preoperative lymph node detection (IRR 8.01, 95% CI 6.11-10.50; p<0.0001) and intrinsic device sensitivity (299 versus 56.5 counts per second; p=0.0003) compared to the conventional gamma camera. Intra-operative assessment with PGC was performed in 64 patients and no additional lymph nodes were visualised. However, the conventional gamma camera demonstrated superior manoeuvrability (p<0.0001). Conclusion: The PGC handheld gamma camera has potential for preoperative sentinel lymph node assessment in patients with BC. Its limited manoeuvrability may hypothetically increase inter- and intra- operator variability. However, appropriate training and frequent use of nuclear medicine and surgical equipment could overcome this limitation.