Improved sampling for a positron emission tomograph

A procedure has been developed for decreasing the sampling interval for positron emission tomographs (PETs). For this procedure to be incorporated into a PET, the gamma ray detectors of the PET must provide depth-of-interaction (DOI) information for the detection of the gamma ray. Four radial, as well as an angular, addresses were provided for each scintillation detector in the tomograph ring for the PET tested. By tilting each detector toward its neighbor, the centers of the four radial segments were displaced one-quarter 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 mm sources separated by 4 mm near the axis 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 sampling points. With the radial data combined for the adjacent radial segments, the 12 sampling points clearly delineated each of the two PSF peaks. Finally, for comparison, the statistical characteristics for PSFs obtained with wobbling detectors were calculated