Gagnon W F, Grant W
Radiology. 1975 Dec;117(3 Pt 1):705-8. doi: 10.1148/117.3.705.
To determine the cause of increased skin reactions near the edges of the field the authors measured doses at and near the surface of the skin with an extrapolation chamber for the gamma-ray beam of an AECL Eldorado 8 60Co irradiator and the x-ray beams of a Varian Clinac 4 linear accelerator, a Varian Clinac 6 linear accelerator, and an ARCO Mevatron 8 linear accelerator. Buildup curves were measured on each machine to locate the depth of the maximum dose (Dmax). The surface dose of the central axis was measured as a function of field size. Off-axis surface doses were measured on the Clinac 4 linear accelerator and on the Eldorado 8 60Co therapy unit. No measurable increase in surface dose was found leading the authors to believe that the observed skin reaction in the axilla for the Clinac 4 linear accelerator is due to a combination of increased dose at Dmax from the anterior mantle field and an increase in exit dose from the posterior mantle field when compared to similar treatments for 60Co.
为了确定射野边缘附近皮肤反应增加的原因，作者使用外推电离室测量了AECL Eldorado 8 60Co辐照器的γ射线束以及Varian Clinac 4直线加速器、Varian Clinac 6直线加速器和ARCO Mevatron 8直线加速器的X射线束在皮肤表面及附近的剂量。在每台机器上测量积累曲线，以确定最大剂量深度（Dmax）。测量中心轴的表面剂量作为射野大小的函数。在Clinac 4直线加速器和Eldorado 8 60Co治疗机上测量了离轴表面剂量。未发现表面剂量有可测量的增加，这使作者认为，与60Co的类似治疗相比，Clinac 4直线加速器腋窝处观察到的皮肤反应是由于前斗篷野Dmax处剂量增加以及后斗篷野出射剂量增加共同导致的。
