Finch J, Bonnett D E
MRC Cyclotron Unit, Clatterbridge Hospital, Bebington, Merseyside, UK.
Br J Radiol. 1992 Apr;65(772):327-33. doi: 10.1259/0007-1285-65-772-327.
The external radiation hazard to radiographers from the use of high-energy neutrons in radiotherapy has been investigated. The contributions from neutron-induced activity in the therapy gantry, the treatment room, the patient and ancillary equipment have been analysed as has the whole-body dose equivalent to radiographers. It was found that there are significant levels of gamma radiation throughout the treatment room, which increase both in the vicinity of the walls in line with the beam axis and in close proximity to the neutron therapy gantry. The mean dose equivalent to radiographers per field treated was found to be 5.1 +/- 1.8 microSv. The dose per field also varied considerably with the particular site being treated but it was found that the dose equivalent per field per minute of set-up time was approximately constant. It was also found that the dose per field increased with the number of patients treated per day commensurate with a build-up of induced activity. The studies also showed that the dose equivalent to radiography staff was comparable to that at other high-energy neutron facilities but significantly greater than that recorded at facilities with low-energy beams.
已对放射治疗师在使用高能中子进行放射治疗时所面临的外部辐射危害展开调查。分析了治疗机架、治疗室、患者及辅助设备中中子诱发放射性所产生的影响，以及放射治疗师的全身剂量当量。研究发现，整个治疗室内存在显著水平的伽马辐射，在与束轴成直线的墙壁附近以及靠近中子治疗机架处，辐射水平均会增加。每治疗一个野，放射治疗师的平均剂量当量为5.1±1.8微希沃特。每个野的剂量也会因所治疗的具体部位而有很大差异，但发现每设置时间每分钟每个野的剂量当量大致恒定。还发现每个野的剂量会随着每天治疗患者数量的增加而增加，这与诱发放射性的累积情况相符。研究还表明，放射摄影工作人员的剂量当量与其他高能中子设施相当，但显著高于低能束设施所记录的剂量。
