Dose corrections for low-density tissue inhomogeneities and air channels for 10-MV x rays.
Dose corrections for low-density tissue inhomogeneities and air channels for 10-MV x rays.
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针对 10-MV X 射线的低密度组织不均匀性和空气通道进行剂量校正。
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
R. Kornelsen
中科院分区：
文献类型：
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作者：
M. E. Young;R. Kornelsen
仅考虑光子注量变化的组织不均匀性校正方法对于10 MV X射线的有用性有限。虽然在软组织中最大积聚深度之外的中心轴上通常存在瞬态电子平衡，但当射束进入低密度材料时，射束轮廓会退化，并且存在横向电子平衡的损失，这会降低不均匀性内部和外部的剂量。本文描述了模拟肺和气道（发生类似效应的地方）后面的大，低密度不均匀性内和附近的剂量的实验测量。讨论了修正系数的计算方法。
Methods of correcting for tissue inhomogeneities which consider only changes in the photon fluence are of limited usefulness for 10-MV x rays. Although there is normally transient electronic equilibrium on the central axis beyond the depth of maximum buildup in soft tissue, when the beam enters a low-density material the beam profile is degraded and there is a loss of lateral electron equilibrium which reduces the dose both within and beyond the inhomogeneity. This paper describes experimental measurements of the dose within and near large, low-density inhomogeneities simulating lungs and also behind air channels (where similar effects occur). Methods of calculating correction factors are discussed.