Geant4 Study of Protons - Tissue Interactions

摘要

Proton beam therapy for cancer treatment uses high-energy protons to destroy cancer cells, a problem that needs immediate attention is the determination of where in the body the protons are hitting, in real time, i.e. during the irradiation. One possibility is to pay attention to the gamma rays produced during the irradiation, and use the information they carry to infer the body part that produced the gamma ray.;This thesis presents the results of an investigation of the interaction of protons with different body parts. Focusing on gamma ray-producing interactions, the goal is to determine the type of interaction that produced the gamma rays. More explicitly, the study uses computer simulations of interactions of proton-tissue, proton-brain, proton-bone, etc., all of which produce gamma rays, to determine the characteristics of the gamma rays produced. If sufficiently different, such gamma ray signatures could be used to design gamma ray detectors that can be used to infer the source of gamma rays during irradiations.;The study uses CERN's GEANT4 particle interaction package to simulate the proton interactions with different body materials, and uses CERN's ROOT statistical package to analyze the data. In particular, the distribution of gamma ray energies, their full-width half-maximum, energy resolution, maximum height, and total number of counts are used as characterizing signatures. Based on these features, the study concludes that it is possible to use the gamma ray spectra to determine what type of interaction produced it.