Speaker
Description
Abstract:
Introduction: Intraoperative gamma probes are essential for localizing radiolabeled tumors and sentinel lymph nodes. However, current fixed-geometry designs suffer from a static trade-off between sensitivity and spatial resolution: high sensitivity is required for rapid lesion detection, while high spatial resolution is critical for precise margin delineation. This work presents the design and validation of a novel, reconfigurable LaBr₃(Ce)-SiPM gamma probe capable of intraoperatively switching between these two performance modes.
Methods: We developed a dual-layer lead collimator assembly defined by six geometric parameters. A validated analytical model, coupled with a multi-objective genetic algorithm (NSGA-II), was employed to explore the theoretical performance limits and identify optimal geometries. The framework was validated against MCNP6 simulations and experimental measurements from 123 distinct physical collimator configurations using a ⁹⁹ᵐTc source. A two-phase computational search was conducted to identify a single "universal" geometry that maximizes tunability.
Results: The optimization identified a universal design capable of adapting to clinical requirements via mechanical adjustment of the collimator layer positions. In High-Sensitivity (HS) mode, the probe achieves a sensitivity of 1483 cps/MBq (at 30 mm SCD), facilitating rapid initial searching. In High-Resolution (HR) mode, the system achieves a spatial resolution of 6.41 mm FWHM (at 30 mm SCD) with adequate sensitivity (206 cps/MBq), enabling precise separation of closely spaced nodes and tumor margins. The LaBr₃(Ce) detector provides superior energy resolution (<7% at 140.5 keV), allowing for effective discrimination between ⁹⁹ᵐTc and ¹²³I.
Conclusion: We successfully demonstrated a single-instrument solution that overcomes the limitations of fixed-collimator probes. This reconfigurable architecture offers surgeons the flexibility to prioritize either detection speed or localization precision on demand. This work has been published in Physics in Medicine & Biology (2026), DOI: 10.1088/1361-6560/ae387e.