Antolak J A, el-Khatib E, Scrimger J W
Cross Cancer Institute, Edmonton, Alberta, Canada.
Med Phys. 1993 Nov-Dec;20(6):1735-42. doi: 10.1118/1.596960.
The dosimetry of arced electron beams is of increasing importance because of the increased capabilities of modern linear accelerators. A practical pencil beam algorithm has been developed for arc electron beams and is capable of using computed tomography information for heterogeneity corrections. For homogeneous phantoms, the maximum dose and bremsstrahlung components are predicted very accurately, that is, within 1% of the maximum dose. However, the depth of maximum dose (treatment depth) is predicted to be deeper than measurement, as much as 0.7 cm deeper. For a heterogeneous lung phantom, the discrepancies are as high as 30%, but the accuracy of dose calculation is consistent with conventional stationary pencil beam algorithms. It was concluded that improvements in the dose prediction are possible with more accurate calculations of the pencil beam widths and the incorporation of range straggling into the algorithm.
由于现代直线加速器功能的增强，弧形电子束的剂量测定变得越来越重要。已开发出一种实用的笔形束算法用于弧形电子束，并且能够使用计算机断层扫描信息进行不均匀性校正。对于均匀体模，最大剂量和轫致辐射分量的预测非常准确，即在最大剂量的1%以内。然而，预测的最大剂量深度（治疗深度）比测量值更深，深达0.7厘米。对于非均匀肺部体模，差异高达30%，但剂量计算的准确性与传统的固定笔形束算法一致。得出的结论是，通过更精确地计算笔形束宽度并将射程离散纳入算法，可以改进剂量预测。
