Impact of Intercrystal Crosstalk on Depth-of-Interaction Information in PET Detectors

We have investigated the impact of intercrystal crosstalk on the spatial resolution of whole body PET detectors with different depth-of-interaction (DOI) readout schemes by validated Monte Carlo simulations. Readout schemes providing both discrete and continuous DOI information were analyzed. Detectors using scintillator crystals of different sizes and different stopping power (LYSO, LaBr₃) were modeled. The results show a similar improvement for the spatial resolution at full width at half maximum across the field of view for all investigated methods. Concerning the resolution at full width at tenth maximum, the discrete approach using two offset layers of crystals is most affected by intercrystal scatter. Continuous DOI readout is least impaired by intercrystal scatter and shows the best results for the full width at tenth maximum.