Lin F J, Leu M Y, Hwang J J
Taiwan Yi Xue Hui Za Zhi. 1989 May;88(5):462-8.
Some of the women undergoing radiation therapy may be pregnant and the scatter radiation to the fetus and gonads is a matter of great concern. Quantitative measurement of the scatter dose in polystyrene solid phantoms with a Farmer type chamber and effects of shielding blocks under the collimators were studied. The scatter dose outside of the primary beam was found to be decreasing exponentially with increasing distance from the radiation beam edge. When the distance increased from 10 cm to 60 cm, the scatter dose drops from 1-2% to 0.15% for the Co-60 beam and from 1-2% to 0.02% for the 10 MV X-rays. The collimation system was a major source of scatter radiation because the scatter dose could be substantially reduced by placing shielding blocks under the collimators and the scatter dosed varied with field sizes. The lead apron used in diagnostic radiographic procedures reduced the scatter dose by 5-6% only. The scatter dose distribution in the body outside of the radiation field was also analyzed.
一些接受放射治疗的女性可能怀有身孕，而散射到胎儿和性腺的辐射是一个备受关注的问题。研究了使用 Farmer 型电离室对聚苯乙烯固体模体中的散射剂量进行定量测量以及准直器下方屏蔽块的效果。发现主射束外的散射剂量随着距辐射束边缘距离的增加呈指数下降。当距离从 10 cm 增加到 60 cm 时，钴 -60 射束的散射剂量从 1 - 2% 降至 0.15%，10 MV X 射线的散射剂量从 1 - 2% 降至 0.02%。准直系统是散射辐射的主要来源，因为通过在准直器下方放置屏蔽块可大幅降低散射剂量，且散射剂量随射野大小而变化。诊断放射程序中使用的铅围裙仅使散射剂量降低了 5 - 6%。还分析了辐射野外身体内的散射剂量分布。
