Simulation Study of a Scintillation Photon Counting TOF-PET Detector Using a Monolithic Crystal and SiPM Array

Time-of-flight positron emission tomography (TOF-PET) detectors capable of advancing coincidence time resolution (CTR) beyond what is currently achieved in state-of-the-art commercial systems can enable higher reconstructed signal-tonoise-ratio (SNR) and image quality due to a number of benefits that stem from more accurate localization of annihilation events along system lines-of-response. The focus of current efforts in this research area is to push system CTR ≤100 ps, where significant gains in reconstructed image SNR and quality would be realized. Accomplishing this goal with a detector that does not sacrifice 511 keV photon detection efficiency is aided by optimal use of scintillation photon statistics for advanced time-of-interaction estimators. TOF-PET detectors which can also position 511 keV photon interactions in three-dimensions (3D) benefit from the ability to account for 3D position of interaction-dependent scintillation photon transit time variance in the time of interaction estimate. We are designing an advanced TOF-PET module to achieve ≤100 ps CTR and accurate 3D event positioning based on a scintillation photon counting detector concept. A parametric design study was performed with an experimentally validated Monte Carlo simulation framework to investigate optimal detector geometry and configuration, guided by achievable CTR and 3D positioning resolution. These studies outline the design of a prototype module to experimentally demonstrate this concept.