Martin Colin J, Barnard Michael
Department of Clinical Physics and Bioengineering, University of Glasgow, Gartnaval Royal Hospital, Glasgow, United Kingdom.
Department of Radiation Physics and Protection, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.
J Radiol Prot. 2022 Jan 18;42(1). doi: 10.1088/1361-6498/ac31c1.
The International Atomic Energy Agency issued a statement calling for action to strengthen the radiation protection of patients undergoing recurrent imaging. This followed reports of patients receiving cumulative effective doses over 100 mSv from multiple computed tomography examinations. In order to evaluate excess risks of cancer incidence among UK patients, data from an exposure management system covering three hospitals within one trust have been studied over 5½ years. Cumulative effective doses for 105 757 patients, from whom 719 (0.68%) received effective dose over 100 mSv, have been analysed using age and sex specific risk factors for stochastic effects. Two cancers might be expected to be initiated in the patients receiving over 100 mSv, while five might be expected to develop cancer among patients receiving 50-100 mSv. However, the calculations ignore health conditions for which the patients are being treated that may shorten their lives, and rely on the linear-no-threshold dose-effect model which is a subject of debate, so they are likely to overestimate cancer incidence. If health of the patients receiving >100 mSv is taken into account, the risk of mortality from cancer initiated by medical exposure might be the order of 1 in 2000. Recommendations on further strengthening of optimisation should be applied to imaging procedures for all patients with special focus on those performed on children and adolescents.
国际原子能机构发表声明，呼吁采取行动加强对接受反复成像检查患者的辐射防护。此前有报道称，患者因多次计算机断层扫描检查而接受的累积有效剂量超过100毫希沃特。为了评估英国患者患癌的额外风险，对一个信托机构下属三家医院的暴露管理系统在5年半时间里的数据进行了研究。已使用针对随机效应的年龄和性别特定风险因素，分析了105757名患者的累积有效剂量，其中719人（0.68%）接受的有效剂量超过100毫希沃特。预计接受超过100毫希沃特剂量的患者中会引发两例癌症，而接受50 - 100毫希沃特剂量的患者中预计会有五例患癌。然而，这些计算忽略了患者正在接受治疗的可能缩短其寿命的健康状况，并且依赖于存在争议的线性无阈剂量效应模型，所以它们可能高估了癌症发病率。如果考虑接受超过100毫希沃特剂量患者的健康状况，医疗照射引发癌症导致的死亡风险可能约为两千分之一。关于进一步加强优化的建议应适用于所有患者的成像程序，尤其要特别关注针对儿童和青少年进行的检查。
