SAIP 2011

Simulation of a pencil proton beam in a water phantom using various monte carlo codes.

14 Jul 2011, 17:00

2h

Asteria

Poster Presentation Track B - Nuclear, Particle and Radiation Physics Poster2

Speaker

Ms Carmen Jacobs (University of the Western Cape)

Description

This study investigates the Pencil Proton Beam scanning technique to determine the dosage obtained during clinical treatments due to secondary radiation. Simulations in MCNPX and GEANT4/GATE are of particular interest in this study. The study is based on a variation of the traditional Hogstrom Pencil beam model for electron beams to provide a description of clinical proton beams. This new Hogstrom model is based on the Fermi-Eyges theory of particle transport. The method used in this investigation is to simulate a proton pencil beam entering a water phantom at various discrete energies and determining the secondary particles distributed throughout the water phantom by studying both Coulombic and Nuclear interactions of the incident proton in water. This allows one to determine how much of the total dosage obtained by the patient is from the primary particle and what part of the dosage is due to the secondary particles. In order to accurately compare the Monte Carlo codes, a further study was done to understand the underlying physics principles used by MCNPX and GEANT4. The development of an analytical model for primary proton beams which included depth distribution, propagations of protons in matter, and scattering theory was also investigated. Besides comparing Monte Carlo codes this study also has real life implications. Pencil beam scanning leads to improving and advancing treatment planning.