Improved sampling for a positron emission tomograph

A procedure has been developed for decreasing the sampling interval for pos itron emission tomographs (PETs). For this procedure to be incorporated int o a PET, the gamma ray detectors of the PET must provide depth-of-interacti on (DOI) information for the detection of the gamma ray. Four radial, as we ll as an angular, addresses were provided for each scintillation detector i n the tomograph ring for the PET tested. By tilting each detector toward it s neighbor, the centers of the four radial segments were displaced one-quar ter of the angular distance between the centers of the untilted detectors. The utility of the improved sampling has been demonstrated by measuring the point-spread-function (PSF) for 1 mn sources separated by 4 mm near the ax is of the PET under test. With the radial data combined for each detector, the PSF peaks were difficult to identify since each peak contained only 3 s ampling points. With the radial data combined for the adjacent radial segme nts, the 12 sampling points clearly delineated each of the two PSF peaks. F inally, for comparison, the statistical characteristics for PSFs obtained w ith wobbling detectors were calculated.