A solid-state intraoperative beta probe system

Successful beta-sensitive intraoperative probes must be capable of detecting relatively small amounts of beta-emitting radionuclides in an environment where a significant photon background exists. The probe system described in this investigation utilized a new photon correction scheme consisting of a stark of two ion-implanted-silicon detectors (IISDs) mounted in a compact unit. The rear detector operated as a photon monitor, whose data was used to correct for photon contamination present in the front detector's readings. The completely battery-powered system incorporated a computer-controlled data acquisition and processing system. Positron and photon detection sensitivities were measured using fluorine-18. The probe was found to have a positron detection sensitivity of 7.21/spl plusmn/0.11 cps/nCi and a 0.0001/spl plusmn/0.0389 cps/nCi photon detection sensitivity. In a simulated search for tumor remnants following a tumor resection using a phantom presenting a realistic annihilation photon background, the intraoperative probe was capable of definitively identifying 12-mm- and 6-mm-diameter, 1-mm-thick disks of simulated tumor.