| 徐慧军,李玉,张素静,朴俊杰,杨晓.G4射波刀蒙特卡罗算法的建立与评价[J].中国医学影像技术,2012,28(10):1932~1935 |
| G4射波刀蒙特卡罗算法的建立与评价 |
| Establishment and assessment of Monte Carlo dose calculation algorithm for G4 Cyberknife |
| 投稿时间：2012-04-07 修订日期：2012-05-13 |
| DOI： |
| 中文关键词: G4射波刀 蒙特卡罗方法 源模型 密度模型 剂量学 |
| 英文关键词:G4 cyberknife Monte Carlo method Source model Density model Dosimetry |
| 基金项目: |
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| 摘要点击次数: 2688 |
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| 中文摘要: |
| 目的 建立G4射波刀照射剂量的蒙特卡罗算法并加以评价。 方法 利用PTW M3水箱、PTW 60012半导体光子探测器测量空气中输出因子、60 mm准直器百分深度剂量和开野剂量曲线得到源分布、注量分布和能谱,并以适当格式输入到射波刀数据库,建立加速器源模型。利用CT扫描CRIS 062密度模体,测量已知物质相对电子密度和质量密度,建立质量密度模型。利用蒙特卡罗算法模拟计算组织模体比、中心离轴比和输出因子,同时用高斯方法调整半高宽,使计算值与射线追踪算法测量值一致。 结果 源分布、注量分布和能谱概率生成源模型,利用源模型和密度模型建立起蒙特卡罗算法,之后运用蒙特卡罗算法模拟计算出组织模体比、中心离轴比、输出因子,其结果与测量结果一致。 结论 成功建立蒙特卡罗算法后,进行认真评价,即可用于计算剂量。 |
| 英文摘要: |
| Objective To establish and assess Monte Carlo (MC) dose calculation algorithm on the exposure dose of G4 Cyberknife. Methods 3D Water phantom and PTW 60012 diode detector were adopted to measure in-air output factor, while 60 mm collimator percent depth dose and the opened field profile were used to generate source distribution, fluence distribution and energy spectrum. After importing the measured beam data to the Cyberknife Data Management System, a calculated source model for the LINAC radiation source was set up. The CRIS 062 density phantom was scanned by using CT, and the relative electron and mass density of the known materials were measured to create the CT density model. And the MC algorithm was used to simulate tissue phantom ratio (TPR), off center ratio (OCR) and output factor (OF). The Gaussion source model was adopted by adjusting the full width half maximum (FWHM) in order to make the calculated value in accord with the measured value of the ray-tracing dose calculation. Results The source model was created by source distribution, fluence distribution and energy spectrum. And Monte Carlo dose calculation algorithm was established by source model and density model. Then the MC algorithm was used to simulate TPR, OCR and OF, which proved the outcome accordance with the measurement. Conclusion After MC Dose calculation algorithm is established and assessed, it can be used in practical dose calculation. |
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