Advanced gamma-probes for radioguided oncological surgery

The capabilities of two new hand-held nonimaging intraoperative /spl gamma/-probes for radioguided oncological surgery are presented and discussed. Both these probes are characterized by using CdTe detectors. The first probe has a classical, cylindrical feature and is based on a square array of four 5 mm/spl times/5 mm detectors, each read separately by its own electronic circuit. An original handling of the signals allows the probe to be sensitive both to the total counting rate and to its relative variation on the scanned plane. The second probe is characterized by two detection systems, each placed at the end of the arms of a tongs-like mechanical device, with the /spl gamma/-radiation entrance windows face to face. The tissues and/or organs to be inspected by surgeon have to be placed between the two detection systems. Each detection system is based on a couple of detectors, 5 mm/spl times/10 mm each and parallel mounted, read separately by its own electronic circuit. The top and bottom couples of detectors are mounted so that to be orthogonal. If one considers the differences between the counts from the two adjacent halves of the top and bottom detectors respectively, the probe works as a zero detector device. A significant improvement in accuracy and time reduction to locate the "hot point", as well as in sensitivity, are reachable by this probe with respect to conventional single detector probes.