Dose verification of Accuray G3 Cyberknife treatment system

• Main Authors: Chao-Hsiung Hung, 洪照雄
• Other Authors: Wei-Li Chen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/37732042919624672238

碩士 === 國立陽明大學 === 放射醫學科學研究所 === 95 === The aims of this study were to simulate the Cyberknife treatment head. The incident electron energy and full width half maximum were determined by comparing the Monte Carlo calculations with the measured data of the percentage depth dose and lateral dose profiles. The relative output factors of Cyberknife were also measured by the radiophotoluminescent glass dosimeters (GDs), thermoluminescent dosimeters (TLDs) and Kodak EDR2 films. Phantom study was also performed to estimate the difference between the experimental measurements and dose calculations by treatment planning system (TPS). In this study, the Monte Carlo simulation of Cyberknife was established. The Initial energy and full width half maximum of the incident electron beam were 6.0MeV and 2.2mm. The difference between the Monte Carlo calculations and the measured percentage depth doses were less than 3%, except the location of 3mm in depth. In the flat area of the lateral dose profile, the difference between the Monte Carlo calculations and the measured data were less than 3%. The relative output factors measured by Kodak EDR2 films, GDs, TLDs were all in agreement , except for the area with the two smallest collimators. The relative output factors for 7.5 and 5 mm collimator measured by Kodak EDR2 films were overestimated as compared to than GDs and TLDs. In anthropomorphic phantom study, the difference between the experimental measurements and TPS calculations was within 5%.