Depth-of-interaction-encoding high-resolution PET detector with sub-nanosecond timing

We present an evaluation of a depth-of-interaction (DOI) encoding PET detector based on dual-end read-out of a scintillator array. One end of the scintillator array is read out using a position sensitive avalanche photodiode (PSAPD), and the other end is read out using a single-channel photomultiplier tube (PMT). The PSAPD signals are used for crystal identification, the PMT signal is used for timing measurement, and the PSAPD and PMT signals are combined to determine the energy and DOI. This design was investigated because it provides the possibility of significant improvements in timing resolution over designs which use PSAPDs to read out both ends of the scintillator array. This detector provided identification of all 64 crystals in the scintillator array, energy resolution of 16.9% FWHM at 511 keV, and timing resolution of 430 ps FWHM vs. a fast reference detector.