白色聚苯乙烯在高能光子剂量测定中作为水的替代品。

White polystyrene as a substitute for water in high energy photon dosimetry.

作者信息

Christ G

机构信息

Department of Medical Physics, University of Tübingen, Germany.

出版信息

Med Phys. 1995 Dec;22(12):2097-100. doi: 10.1118/1.597652.

DOI:10.1118/1.597652

PMID:8746716

Abstract

White polystyrene (C8H8 with 2 wt. % to TiO2) has been compared to water using photon beams with nominal accelerating potential of 4 MV, 6 MV, 15 MV and 25 MV. The absolute reading and hence the measured absorbed dose is found to be up to 3% lower in white polystyrene which can be taken into account by using a correction factor. From these data differences in relative measurements (TMR or percentage depth dose) can be calculated showing differences of less than 0.7% normalized to maximum dose. Since the correction factor shows a dependence on photon energy and field size the use of a common scaling factor is not possible. The effect on photon dosimetry is discussed.

摘要

已将白色聚苯乙烯（C8H8，含2 wt.% 的TiO2）与水进行比较，使用标称加速电位为4 MV、6 MV、15 MV和25 MV的光子束。发现在白色聚苯乙烯中绝对读数以及由此测量的吸收剂量低至3%，可通过使用校正因子来考虑这一点。根据这些数据，可以计算出相对测量值（组织最大剂量比或百分深度剂量）的差异，相对于最大剂量归一化后显示差异小于0.7%。由于校正因子显示出对光子能量和射野大小的依赖性，因此不可能使用通用的缩放因子。文中讨论了其对光子剂量学的影响。