INVESTIGATION OF THE CONVOLUTION METHOD FOR POLYENERGETIC SPECTRA
INVESTIGATION OF THE CONVOLUTION METHOD FOR POLYENERGETIC SPECTRA
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DOI：
10.1118/1.597154
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发表时间：
1993-09-01
期刊：
影响因子：
3.8
通讯作者：
RECKWERDT, P
中科院分区：
文献类型：
--
作者：
PAPANIKOLAOU, N;MACKIE, TR;RECKWERDT, P
使用两种正确考虑光束硬化效应的卷积方法计算了撞击水体模的多能光子束每单位注量的绝对剂量分布。先前使用 EGS4 蒙特卡罗代码计算的剂量沉积内核与主术语卷积，以给出能量范围从 100 kev 到 50 MeV 的单能光子束的剂量。多能剂量分布由单独计算的单能分量组成，这些分量通过注量谱适当加权以产生多能剂量分布。或者，考虑多能光束的单个卷积，其中复合多能核与相应的多能项进行卷积。还检查了由于光束硬化引起的多能核方差的影响以及发散光束几何形状的倾斜核的影响。使用两种提出的方法产生的深度剂量数据与测量数据和蒙特卡罗模拟进行了比较，显示出良好的一致性。
The distribution of absolute dose per unit fluence from polyenergetic photon beams impinging upon a water phantom was calculated using two convolution approaches that properly account for beam hardening effects. Dose deposition kernels calculated previously using the EGS4 Monte Carlo code are convolved with the primary terma to give the dose for monoenergetic photon beams of energies ranging from 100 kev to 50 MeV. A polyenergetic dose distribution is composed of separately calculated monoenergetic components, which are appropriately weighted with the fluence spectrum to yield the polyenergetic dose distribution. Alternatively, a single convolution for the polyenergetic beam is considered, where a composite polyenergetic kernel is convolved with the respective polyenergetic terma. The effects of the polyenergetic kernel variance due to beam hardening as well as the effect of tilting the kernels for a diverging beam geometry were also examined. The depth dose data produced using the two proposed methods were compared with measured data and Monte Carlo simulations and showed good agreement.