Análise comparativa entre modelagem computacional e dados experimentais para tomografia computadorizada com feixe de prótons

Abstract

In this work comparative analyses between computational simulations and experimental data for the prototype of a proton beam mini-tomograph are presented. The first step was to construct virtually two models of phantoms. Simulation programs were used based on the Monte Carlo method: Geant4 version 9.4p02 and SRIM 2010. A phantom was designed using polypropylene (PP), water and air in tubular structure. This phantom in PP is dedicated to studies in tomographic reconstruction. The other phantom uses high density polyethylene (HDPE) in disk form with thickness of 3 mm, 4 mm and 5 mm. These are dedicated to experiment of energy loss of protons. Once completed the simulation part, the phantoms were constructed with precision machining. X-ray tomographic images of the phantom in PP were obtained with the micro-tomograph of the Polytechnic Institute from UERJ, for later comparison with the simulations. The HDPE disk phantoms were irradiated with 24 MeV energy proton beams at the cyclotron of the Institute of Nuclear Engineering (IEN). The reconstructed images of the phantom in PP with simulated data showed a good approximation of the structure when compared with x-ray tomographic images. The experiment of proton energy loss at IEN showed a great approximation with the simulated data obtained with Geant4 and SRIM.