A GSO(Ce) block type detector for high count rate PET applications

The benefits of block type detectors for PET applications are well understood and are provided by commercial BGO and NaI(Tl) systems. In order to extend the count rate capabilities for many applications, a block type detector using GSO(Ce) has been designed, constructed, and tested. GSO(Ce) crystals are shown to produce 2.9 times the effective light output of BGO and yield an energy resolution of 11% FWHM for 511 keV photons. An assembly of a square array of 36 crystals measuring 4.5×4.5×30 mm coupled to 4 cylindrical photomultiplier tubes produces signals which are sampled and recorded within 150 nsec. The computed Anger plot demonstrates individual detector delineation for both flood field and collimated beam illumination. The 56 nsec decay time of the emissions of GSO(Ce) coupled with the small size of the block should realize approximately an order of magnitude improvement in count rate over many current commercial BGO block detector modules based on dead time considerations