A Time Efficient Optical Model for GATE Simulation of a LYSO Scintillation Matrix Used in PET Applications

Abstract

A time efficient optical model is proposed for GATE simulation of a LYSO scintillation matrix coupled to a photomultiplier. The purpose is to avoid the excessively long computation time when activating the optical processes in GATE. The usefulness of the model is demonstrated by comparing the simulated and experimental energy spectra obtained with the dual planar head equipment for dosimetry with a positron emission tomograph ( DoPET). The procedure to apply the model is divided in two steps. Firstly, a simplified simulation of a single crystal element of DoPET is used to fit an analytic function that models the optical attenuation inside the crystal. In a second step, the model is employed to calculate the influence of this attenuation in the energy registered by the tomograph. The use of the proposed optical model is around three orders of magnitude faster than a GATE simulation with optical processes enabled. A good agreement was found between the experimental and simulated data using the optical model. The results indicate that optical interactions inside the crystal elements play an important role on the energy resolution and induce a considerable degradation of the spectra information acquired by DoPET. Finally, the same approach employed by the proposed optical model could be useful to simulate a scintillation matrix coupled to a photomultiplier using single or dual readout scheme

CCMod: a GATE module for Compton camera imaging simulation

“…The digitization of optical photons has not been considered in CCMod. The performed simulations do not include the generation and transport of optical photons which highly increase the computational cost (Bonifacio et al 2010). However, several digitization modules, such as DoI module which models the influence of the light distribution on the 3-dimensional spatial resolution of the detector, have been implemented aiming at reproducing the response of scintillator crystals.…”

A GATE Simulation Study of the Siemens Biograph DUO PET/CT System

“…A reason is that it is generally difficult to model individual components of a scanner because of limited information from manufacturers about their designs-or incomplete physical characterisation of phenomena, such as optical transport in scintillators [5,25,26]. Usually the models employ analytical dead time simulations based on experimental data from the scanner [27,28], coincidence processing algorithms [27], or fixed values for physical parameters that give reasonable agreement to experimental results [11,29].…”

Analytical modeling of the sensitivity of cylindrical PET systems based on bulk materials and metascintillators

“…A common issue with Monte Carlo simulation is the expected deviation between simulated and experimental data. This is due to some parameters potentially chosen ideally, without taking into account secondary but non-negligible effects [19]. Sometimes the physical characteristics of the simulated architecture are not accurately chosen, such as for instance the density or stopping power of L(Y)SO:Ce, where the percentage of yttrium or different dopages play a role in the attenuation length and timing characteristics.…”