以最小平方法估測質子能量;Proton Energy Estimation by Least Square Method

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題名:	以最小平方法估測質子能量;Proton Energy Estimation by Least Square Method
作者:	劉飛那;Wijayanti, Lovina
貢獻者:	物理學系
關鍵詞:	最小平方法;質子能量;質子;proton energy estimation;least square;proton
日期:	2017-07-24
上傳時間:	2017-10-27 13:41:22 (UTC+8)
出版者:	國立中央大學
摘要:	質子治療是現今放射治療中最佳選擇之一，其布拉格峰特性確保不會傷害在峰後的正常或較敏感的細胞組織，所以計算劑量所用模擬計算必須力求精確。可是不同模擬（如GEANT 4, FLUKA, MCNP6）內部採用不同模型計算可能造成結果有些微差別。為此，我們在日本大阪大學RCNP（Research Center for Nuclear Physics）進行質子散射實驗以驗證不同模擬，同時此實驗也利用射程測量儀（Range Finder）測量質子散射後殘餘動能。此論文就射程測量儀設計以最小平方法（Least Square method）分別估算入射能量為160 MeV及60-78 MeV之質子能量，得能量解析度分別為~1 MeV及~0.5 MeV，證明以最小平方法估算入射質子之動能確實可行。另外，從臨床觀點而言，以質子治療眼癌需要精確而且能量在63.5 MeV左右質子束，若將此論文方法套用於商用儀器(如IBA Zebra)以估算低能量質子時，應可延伸此儀器適用範圍，滿足治療眼癌之需求。;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.
顯示於類別:	[物理研究所] 博碩士論文

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