Brockstedt S, Holstein H, Jakobsson L, Tomaszewicz A, Knöös T
Radiation Physics, Skåne University Hospital, Lund, Sweden Medical Radiation Physics, Lund University, Lund, Sweden
Radiation Physics, Skåne University Hospital, Lund, Sweden Medical Radiation Physics, Lund University, Lund, Sweden.
Radiat Prot Dosimetry. 2015 Jul;165(1-4):464-7. doi: 10.1093/rpd/ncv046. Epub 2015 Mar 22.
During the radiation survey of a reinstalled 10-MV linear accelerator in an old radiation treatment facility, high dose rates of neutrons were observed. The area outside the maze entrance is used as a waiting room where patients, their relatives and staff other than those involved in the actual treatment can freely pass. High fluence rates of neutrons would cause an unnecessary high effective dose to the staff working in the vicinity of such a system, and it can be several orders higher than the doses received due to X-rays at the same location. However, the common knowledge appears to have been that the effect of neutrons at 10-MV X-ray linear accelerator facilities is negligible and shielding calculations models seldom mention neutrons for this operating energy level. Although data are scarce, reports regarding this phenomenon are now emerging. For the future, it is advocated that contributions from neutrons are considered already during the planning stage of new or modified facilities aimed for 10 MV and that estimated dose levels are verified.
在对一个旧的放射治疗设施中重新安装的10兆伏直线加速器进行辐射测量时，观察到了高剂量率的中子。迷宫入口外的区域用作候诊室，患者、其亲属以及实际治疗以外的工作人员可以自由通行。高中子注量率会给在这样一个系统附近工作的人员造成不必要的高有效剂量，并且可能比在同一位置因X射线所接受的剂量高出几个数量级。然而，人们普遍认为在10兆伏X射线直线加速器设施中中子的影响可以忽略不计，并且屏蔽计算模型很少提及该运行能量水平下的中子。尽管数据稀少，但现在有关这种现象的报告正在出现。展望未来，建议在针对10兆伏的新设施或改造设施的规划阶段就考虑中子的贡献，并对估计的剂量水平进行验证。
