Design Studtes of Two Possible Detector Blocks for High Resolution Positron Emission Tomography of the Brain

Two possible detector designs for high resolution positron camera systems have been investigated. The goal is to achieve an instrument that can measure the whole brain with a spatial resolution of 5 mm FWHM in all directions. For both detectors BGO crystals are used, with the dimension 4.5*9.5*25 mm. One detector scheme utilizes the Anger principle for crystal identification with 16 crystals mounted on two dual PMT:s via a 3 mm light guide. The other detector scheme utilizes position sensitive PMT:s. The figures of merit for these two configurations are discussed in terms of high count rate capabilities and identification reliability.