Proton Energy Estimation by Least Square Method

• Main Authors: Lovina Wijayanti, 劉飛那
• Other Authors: Augustine E. Chen
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/63hj38

碩士 === 國立中央大學 === 物理學系 === 105 === Proton therapy has become one of the most promising radiation techniques for nowadays cancer treatment. A special dose characteristic of proton called as Bragg peak has contributed to spare the dose for normal tissues surrounding cancer. In order to obtain the benefit of Bragg peak, a well-known physics calculation model is needed by treatment planning system to calculate proton dose distribution before it is delivered to the patient. Monte Carlo simulation code is the most used code for the proton simulation. However, different Monte Carlo codes, such as GEANT4, FLUKA, MCNP6, give different approaches when they are used to simulate the passage of protons through the material. Therefore, a proton multiple scattering experiment at Research Center for Nuclear Physics (RCNP), Osaka University has been conducted to verify the agreement between simulation and experimental data. One of the aims in RCNP experiment was to measure the remaining proton kinetic energy by using the Range Finder. For this reason, in this simulation study, the Range Finder was used to estimate the incident proton energy by Least Square method. The Least Square method has been applied to estimate a 160 MeV and 60 – 78 MeV incident proton one-by-one. This method was found to provide ~ 1 MeV accuracy when it used to estimate a 160 MeV incident proton and ~ 0.5 MeV accuracy when it used to estimate the 60 – 78 MeV incident proton. This result shows that Least Square is an effective method for estimating incident proton energy. Furthermore, from a clinical application point of view, the Least Square method has also been applied to estimate 63 – 65 MeV monoenergetic proton planar beam source and it was found to provide ~ 0.2 MeV accuracy. This result implies that in the future, the LS method may be used to improve the proton beam energy measurement for such a low proton energy, especially to treat ocular cancer which usually needs the proton with an incident energy of 63.5 MeV.