A novel DOI detector design with high encoding ratio for PET applications

We designed a novel detector module combining the dual-ended readout design with the traditional block detector for resolving depth of interaction (DOI) and enabling high encoding ratio (number of scintillation crystals per photodetector) and high photon collection efficiency. The design and performance of the dual-ended readout block detector were investigated using Monte-Carlo simulation. Detector modules of varying encoding ratios were modeled and photons were generated and tracked within the module to determine the geometric X, Y (crystal identification), DOI resolutions and collection efficiency of the system. The X and Y resolutions were expressed as the error in identifying the interacting scintillation crystal and the resolutions were optimized for each encoding ratio by adjusting the thickness of the optical light guide. Results showed that a detector module with an encoding ratio up to 3.125 with 2 mm light guides can achieve minimal error in identifying the interacting scintillation crystal, <; 2 mm resolution in depth of interaction FWHM, and >; 65% collection efficiency. This design allows for a 6.25 fold reduction in the number of channels compared to a one-to-one dual-ended readout configuration.