Characterization of performance of a miniature, high sensitivity gamma ray camera

A compact, hand-held gamma camera with excellent intrinsic and extrinsic performance has been developed for the rapid identification and localization of the sentinel lymph node during the surgical staging of cancer. A goal for this device is an image acquisition time of five seconds to allow the surgeon to easily search for points of interest without excessive motion blurring. The camera comprises a 5×5 cm² field of view NaI (TI) pixellated crystal array, a high sensitivity (2.0 cm thick) hexagonal parallel-hole collimator, a position sensitive photomultiplier tube (PSPMT), and a novel highly multiplexed electrical readout. The good intrinsic energy resolution (12.3±2.6%) resolution, extrinsic sensitivity (5 cps/μCi with 24% energy window) and extrinsic spatial resolution (1.6+/-0.02 mm at 0.5 cm) facilitate rapid identification of a hot node.