Intraoperative Gamma Probe for Locating Cancerous Lymph Nodes

摘要

A novel concept of an intraoperative gamma probe was simulated using GATE opensource software for the purpose of detectingand identifying sentinel lymph nodes during sentinel lymph node mapping. The probe is made of a pixelated BismuthGermanium Oxide scintillator, BGO, which will be coupled to a Silicon Photomultiplier (SiPM) to collect the scintillationlight. The probe detector has 9 pixels, each pixel is 3 × 3 mm2, for a total detection active area of 81 mm~2. The detector heightis 5 mm long. The probe detector was able to identify small sentinel lymph nodes with a 4 mm diameter. Sentinel nodes wereplaced at 6 different heights away from the detector surface starting at 2 mm up to 12 mm with 2 mm increments at eachheight. The pixel with the node directly above, node center is at the same axis as the pixel center, had consistently registeredgreater number of counts compared to neighboring pixels. Moving the sentinel node over all detector pixels produced similarresults, where the pixel with the source directly above produced greater counts. Each pixel on the detector surface has a 2πsteradian solid angle, so collectively the detector has the same solid angel, but as wide as the detector whole area. Dependingon the shielding used around the probe head, the solid angle can be minimized or maximized to investigate a specific areaduring the mapping process of lymph nodes.