GEANT4 simulation in proton medical imaging: A transport models comparison

Imaging techniques using protons are currently being actively developed for proton therapy. Presently, many researchers use the GEANT4 toolkit to simulate proton imaging devices, without, however, detailed analysis of its precision for the case of thick absorbers. In this paper we present a systematic comparison of the quantities important for proton imaging as simulated by different physics lists of GEANT4 (version 9.6.p03) in the conditions close to those of proton medical imaging. We evaluated the physics lists FTF_BIC_EMY, FTFP_BERT_EMY, QGSP_BERT_95_EMY, QGSP_BERT_EMY, QGSP_BIC_EMV, and QGSP_BIC_EMY. The kinetic energies, angles, and coordinates of protons exiting the absorber were analysed. The significant differences in the physical observables were detected between EMY and EMV models of electromagnetic processes. The difference between BERT and BIC models of nuclear processes is at least 10 times smaller. The obtained results may be used not only in proton imaging but also as a test for nuclear models in future experiments with thick absorbers.