Lambert G D, Sandland M R, Whitton A C, Doughty D
Int J Radiat Oncol Biol Phys. 1985 Mar;11(3):617-20. doi: 10.1016/0360-3016(85)90197-x.
In electron beam therapy, backscattered electrons from metal shields result in a high dose to tissue in the vicinity of the shield. Data are now available which enable both the magnitude of the dose enhancement at the interface and the fall off in dose 'up stream' to be determined. With the aid of these data, a combined modality therapy (5 MeV electrons, 1.1 mm A1 HVL X rays) was given to an eyelid during which the lens was protected with a superficial X ray lead eye shield. The eyelid was treated to a mid lid dose of 45 Gy in 28 days, and the dose gradient on the beam central axis was more uniform (+/- 3%) than that obtainable with superficial X rays alone. The lens dose from the combined therapy was estimated to be less than 0.25 Gy.
在电子束治疗中，来自金属屏蔽的反向散射电子会在屏蔽附近的组织中产生高剂量。现在已有数据可用于确定界面处剂量增强的幅度以及“上游”剂量的下降情况。借助这些数据，对一只眼睑进行了联合模式治疗（5兆电子伏特电子，半值层为1.1毫米铝的X射线），在此期间用浅层X射线铅眼罩保护晶状体。眼睑在28天内接受了45戈瑞的中睑剂量治疗，且束中心轴上的剂量梯度比仅使用浅层X射线时更均匀（±3%）。联合治疗的晶状体剂量估计小于0.25戈瑞。
