Validation of the Monte Carlo Simulation of a Siemens Biograph mCT PET

Abstract

Geant4 Application for Tomography Emission (GATE) is a simulation platform based on GEANT4. It is designed to perform numerical simulations in medical imaging and radiotherapy. It is also used to simulate Emission Tomography (Positron Emission Tomography, PET and Single Photon Emission Computed Tomography, SPECT), Computed Tomography (CT) and Radiotherapy experiments. The purpose of this study is to validate a GATE model of the commercial PET/CT Siemens Biograph, the latest acquisition of the Clinical Hospital of Salamanca. The geometry of the system has been implemented in GATE, including the detector ring, the crystal blocks, the PMTs etc. Radionuclides for all measurements shall be $^{18}$F and a cylindrical source type twogamma (which has no attenuation). The GATE simulated results are directly compared to experimental data obtained using a number of NEMA NU-2-2007 performance protocols, including sensitivity and scatter fraction. The PET data generated using GATE can be reconstructed using STIR (Software for Tomographic Imagen Reconstruction). STIR is an open source software, written in C++, consisting of classes, functions and utilities for 3D PET image reconstruction, although it is general enough to accommodate other imaging modalities. Finally we will compare our simulated model with experimental values of the scanner they have at the hospital in Salamanca.