Design considerations of an animal PET scanner utilizing ESO scintillators and position sensitive PMTs

Various parameters relevant to the design of a small scale PET scanner were studied both experimentally and by computer simulation. LSO (cerium-doped lutetium oxyorthosilicate) was compared with EGO, using a position sensitive PMT (PSPMT). (Compared to EGO, LSO has 8 times faster decay time, 4 times the scintillation light output, but 14% lower attenuation coefficient for 511 keV photons). The experiments with EGO and LSO involved: the crystal identification on the face of a PSPMT, measurement of the coincidence line-spread functions, and measurement of the sensitivity above the electronic noise. The resulting coincidence images clearly resolved each LSO crystal. EGS4 Monte Carlo simulations were used to estimate the efficiency, singles rate and mispositioning due to the depth of interaction for PET scanners with various sizes of LSO and EGO.<>