A pulse simulator for crystal identification validation of phoswich detectors used in positron emission tomography

Abstract

Crystal identification (CI) of phoswich detectors is a technique used in positron emission tomography (PET) for improving spatial resolution through depth-of-interaction determination or higher pixelization. Digital algorithms using advanced digital signal processing techniques currently provide the most powerful approaches for CI of phoswich detectors made of crystals with only slightly different scintillation decay times. Such methods can be implemented in the all-digital architecture of LabPET, a small animal PET scanner developed in Sherbrooke, for fast and accurate real-time CI. In order to validate the new CI algorithms and assess their performance for different front-end electronics, a pulse generator simulator was developed to generate PET signals and investigate the effects of factors such as electronic noise, photon statistics and pulse shaping filter. The pulse generator was validated with LabPET-like pulses and CI results were compared with experimental data. The pulse simulator enables CI algorithms to be validated together with detector performance such as energy and timing resolution at an early stage of scanner design.