Verification by Monte Carlo methods of a power law tissue-air ratio algorithm for inhomogeneity corrections in photon beam dose calculations.
Verification by Monte Carlo methods of a power law tissue-air ratio algorithm for inhomogeneity corrections in photon beam dose calculations.
复制标题
通过蒙特卡罗方法验证幂律组织空气比算法，用于光子束剂量计算中的不均匀性校正。
DOI：
10.1088/0031-9155/25/2/003
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发表时间：
1980
影响因子：
3.5
通讯作者：
R. A. Fox
中科院分区：
文献类型：
--
作者：
S. Webb;R. A. Fox
本文用蒙特卡罗方法计算了60Co外照射与不均匀介质相互作用产生的轴向和离轴深度剂量分布。一个近似的应用蒙特卡罗数据的配置，其中的横向范围的不均匀性小于束区，也提出。这些新的Monte Carlo技术依赖于从小面积的组成子束的剂量分布的积分，并且该方法的准确性因此与束尺寸无关。的幂律校正方程描述的剂量分布在组织不均匀性的存在下，推导出在其最一般的形式。通过与蒙特卡罗参考数据的比较，验证了该方程可用于常规患者剂量测定。它解释了为什么蒙特卡罗数据可以被视为一个基本的参考点，在执行这些测试的扩展到的Eschericho方程。其他分析校正技术，如等效放射路径法，被证明是不太准确的。结合CT扫描仪数据的广义幂律方程的应用进行了讨论。为了便于介绍，蒙特卡罗技术的细节和分析公式已被分离到附录中。
A Monte Carlo computer program has been used to calculate axial and off-axis depth dose distributions arising from the interaction of an external beam of 60Co radiation with a medium containing inhomogeneities. An approximation for applying the Monte Carlo data to the configuration where the lateral extent of the inhomogeneity is less than the beam area, is also presented. These new Monte Carlo techniques rely on integration over the dose distributions from constituent sub-beams of small area and the accuracy of the method is thus independent of beam size. The power law correction equation (Batho equation) describing the dose distribution in the presence of tissue inhomogeneities is derived in its most general form. By comparison with Monte Carlo reference data, the equation is validated for routine patient dosimetry. It is explained why the Monte Carlo data may be regarded as a fundamental reference point in performing these tests of the extension to the Batho equation. Other analytic correction techniques, e.g. the equivalent radiological path method, are shown to be less accurate. The application of the generalised power law equation in conjunction with CT scanner data is discussed. For ease of presentation, the details of the Monte Carlo techniques and the analytic formula have been separated into appendices.