Electron dose calculation using multiple-scattering theory: localized inhomogeneities--a new theory.
Electron dose calculation using multiple-scattering theory: localized inhomogeneities--a new theory.
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使用多重散射理论计算电子剂量：局部不均匀性——一种新理论。
DOI：
10.1118/1.596698
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发表时间：
1991
期刊：
影响因子：
3.8
通讯作者：
Jette,D
中科院分区：
文献类型：
--
作者：
Jette,D
在使用多重散射理论计算电子剂量系列的第四篇文章中，我们通过求解散射功率的费米方程来处理局部不均匀性，散射功率是位置的任意函数。事实上，我们更进一步，通过求解取代（一阶）费米方程的二阶多重散射方程，再次求解作为位置的任意函数的散射功率。因此，我们不再像费米-艾格斯理论那样局限于水平分层介质。我们的通用解决方案采用扰动级数的形式，它显然收敛得足够快，只需取其前两项或三项即可进行精确的剂量计算。关于初级电子直接沉积的能量，本文中提出的公式与厚半板结构的蒙特卡罗计算非常一致，正如本系列的下一篇文章中所见。此外，我们的一阶、二阶公式在傅里叶变换空间中表达时足够简单，可以在治疗计划系统中实现，为任意不均匀性配置提供完整的三维电子剂量计算。
In this fourth article in a series on the calculation of electron dose using multiple‐scattering theory, we deal with localized inhomogeneities by solving the Fermi equation for scattering power which is an arbitrary function of position. In fact, we go further, by solving the second‐order multiple‐scattering equation which supersedes the (first‐order) Fermi equation, again for scattering power which is an arbitrary function of position. Thus, we are no longer restricted to a horizontally layered medium, as is the case with the Fermi–Eyges theory. Our general solution is in the form of a perturbation series which evidently converges rapidly enough that only its first two or three terms need be taken for accurate dose calculation. Regarding the energy directly deposited by the primary electrons, the formulas developed in this article give very good agreement with Monte Carlo calculations for the thick half‐slab configuration, as will be seen in the next article in this series. Moreover, our first‐rank, second‐order formulas, when expressed in Fourier‐transformed space, are simple enough to be implemented in a treatment planning system providing full three‐dimensional electron dose calculation for arbitrary configurations of inhomogeneities.