Monte Carlo model validation of a detector system used for Positron Emission Particle Tracking

Abstract

The spatiotemporal resolution of Lagrangian particle trajectories captured using Positron Emission Particle Tracking (PEPT) is difficult to predict prior to experimentation, since this relies on the detector systems, source activity distribution, and experimental apparatus. However, understanding the limitations of an experiment is crucial to quantifying error and ensuring that the captured trajectories reveal phenomena of interest in enough detail for meaningful analysis. These factors are especially important in PEPT experiments since this technique is applied to image opaque systems lacking optical access for complementary measurement techniques, such as Particle Image Velocimetry. Using the Monte Carlo simulator Geant4 Application for Tomographic Emission (GATE), a computational model of the ADAC/Phillips Forte, a detector system used at the Positron Imaging Centre (PIC) for PEPT studies, is created and validated against experiments testing the spatial resolution, sensitivity, scatter fraction, and count-rates following National Electronic Manufactures Association standards. In this work, fluorine-18 sources and experimental geometries are recreated, generating synthetic data analogous to experimentally acquired data. Over all experiments and activities tested, this GATE model reports agreement to within 1%–10% of experiments. In the future, this model is expected to be used by the PIC to conduct feasibility studies of potential experiments. Further, optimization of experiments can now be conducted without expending the considerable time and resources required for physical experimentation, representing a major improvement of the PIC’s PEPT modeling capabilities.