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文摘
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目的:蒙特卡罗方法可以精确地对放射治疗过程所涉及到的物理过程进行模拟而在放射治疗领域有很大应用前景,本文发展了基于蒙特卡罗程序MCNP 的剂量计算验证方法。用户只需要设置加速器源的位置参数和放疗计划参数就可以方便的调用MCNP 源子程序完成放疗计划的剂量计算。方法:首先确定源的位置,根据加速器机头的位置和等中心点的位置来确定源粒子的位置信息。其次根据代表射野形状和强度的强度矩阵来抽样源粒子的方向信息,然后根据加速器能谱的抽样概率随机抽选能量段,然后在能量段内均匀抽样,得到该次抽样的源粒子能量信息,得到源粒子的所有信息后即可进行粒子在人体的蒙卡输运模拟。结果: 本文通过对一例真实的宫颈癌病例的放疗计划进行模拟计算剂量分布,通过剂量偏差分析得到与MCFSPB 在目标区域的平均误差为1.12%,γ 分析值为94.55%,剂量计算结果符合的很好,比临床上的标准要求要高,完全满足临床要求。结论: 本方法的计算精度能满足临床放射治疗验证的要求,能作为放疗计划的验证工具。 |
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其他语种文摘
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Objective Monte Carlo method has been widely applied in clinical dose calculation of radiation therapy. So a dose calculation method was developed in this paper which could accurately describe the radiation field with arbitrary shape and the intensity to verify the accuracy of radiation therapy planning based on the MCNP source subroutine. Methods Firstly, we determined the location of the source particles according to the accelerator position and the head position of the isocenter position. Then, a plane was supposed paralleled to the isocenter plane between the accelerator head and phantom, using a two-dimensional intensity matrix to represent the field. The plane was divided into grids corresponding to the matrix, randomly sampling the point in the plane to obtain the source particle's position. We drew the straight line from the accelerator point source to the particle position to obtain source particle direction. The spectra was sampled to obtain the source particle energy. Thus the particle's energy, direction and position in the plane could be identified. Then the dose distribution in the patient geometry could be simulated based on above sources. Results Tested by a clinical treatment plan of cervical cancer simulation dose distribution and compared with MCFSPB, the average error in the target area is 1.12%, γ analysis is 94.55%. Conclusion This method can fully meet the clinical requirements and be used as the treatment planning tool for validation. |
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来源
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中国医学物理学杂志
,2015,32(1):13-16,20 【扩展库】
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关键词
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MCNP
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源子程序
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放射治疗
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放疗计划验证
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地址
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1.
中国科学技术大学, 中国科学院中子输运理论与辐射安全重点实验室, 安徽, 合肥, 230027
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中国科学院核能安全技术研究所, 中国科学院中子输运理论与辐射安全重点实验室, 安徽, 合肥, 230031
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FDS团队
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1005-202X |
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学科
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预防医学、卫生学 |
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基金
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国家自然科学基金
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ITER 项目
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文献收藏号
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CSCD:5341882
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