Dual-detector probe for surgical tumor staging.

A hand-held, dual-detector probe has been developed for surgical tumor staging. This dual probe simultaneously monitors counts from a possible tumor site along with counts from adjacent normal tissue using two concentric, collimated scintillation detectors. A comparison of counts from the detectors can distinguish a small tumor directly in front of the probe from variations in background activity. The probe was tested in computer simulations of surgical staging of metastases to para-aortic and iliac lymph nodes using a spatial response map of the probe, a numerical torso phantom, and organ activity data for [57Co]bleomycin in rabbits. Results show that the dual probe performs better than a single-detector probe in detecting tumors and solves the problem caused by spatial variations in the background source distribution.