Adams E J, Hounsell A R
North Western Medical Physics Department, Christie Hospital, Manchester, UK.
Radiother Oncol. 1995 Dec;37(3):225-9. doi: 10.1016/0167-8140(95)01662-7.
Doses in the build-up region have been compared for regular fields with and without a perspex accessory tray and for two irregular fields defined by either a Philips multi-leaf collimator (MLC) or lead blocks. The results show an increase in doses within the build-up region, by up to a factor of two, primarily due to the presence of the accessory tray. Fields shaped with the MLC exhibited build-up characteristics similar to those in unblocked fields and hence there will be systematic changes to the build-up dose when treatments are transferred from lead blocking techniques to those using an MLC mounted within the treatment head.
已对有和没有有机玻璃附件托盘的常规射野以及由飞利浦多叶准直器（MLC）或铅挡块定义的两个不规则射野在建成区的剂量进行了比较。结果表明，建成区内的剂量增加了，最高可达两倍，这主要是由于附件托盘的存在。用MLC形成的射野表现出与无遮挡射野类似的建成特性，因此，当治疗从铅挡技术转换为使用安装在治疗头内的MLC的技术时，建成剂量将会有系统性变化。
