Baysson H, Etard C, Brisse H J, Bernier M-O
IRSN, DRPH, SER, laboratoire d'épidémiologie, BP17, 92262 Fontenay-aux-Roses cedex, France.
Arch Pediatr. 2012 Jan;19(1):64-73. doi: 10.1016/j.arcped.2011.10.023. Epub 2011 Nov 29.
The question of the risk of cancer associated with postnatal diagnostic medical exposure involving ionizing radiation in childhood is particularly relevant at the moment given the growing use of diagnostic examinations, especially computed tomography scans, in children. Compared to adults, pediatric patients are more sensitive to radiation and have more years of life expectancy and therefore more years at risk of cancer occurrence as compared to adults. This paper provides a description of diagnostic x-ray exposure in children in France and summarizes epidemiologic studies on subsequent risk of cancer. Overall, this review, based on 12 case-control studies and 6 cohort studies, shows no significant association between exposure to medical diagnostic radiation exposure and childhood cancer risk. The methodological limitations of these studies are discussed. As the expected cancer risks are low, epidemiological studies require very large sample sizes and long periods of follow-up in addition to a good dosimetry assessment to enable quantitative risk estimation. New cohort studies of young patients who underwent CT scans are currently underway within the European EPI-CT project. In the meantime, continued efforts to reduce doses and the number of radiological examinations in children are needed, including adhering to the "as long as reasonably achievable" (Alara) principle.
鉴于目前儿童诊断性检查尤其是计算机断层扫描的使用日益增加，与儿童期接受涉及电离辐射的产后诊断性医疗照射相关的癌症风险问题目前尤为重要。与成人相比，儿科患者对辐射更敏感，预期寿命更长，因此与成人相比，患癌风险期也更长。本文描述了法国儿童的诊断性X线照射情况，并总结了关于随后患癌风险的流行病学研究。总体而言，基于12项病例对照研究和6项队列研究的这篇综述表明，医疗诊断性辐射照射与儿童癌症风险之间无显著关联。文中讨论了这些研究的方法学局限性。由于预期的癌症风险较低，流行病学研究除了需要良好的剂量测定评估以进行定量风险估计外，还需要非常大的样本量和长时间的随访。欧洲EPI-CT项目目前正在对接受CT扫描的年轻患者开展新的队列研究。与此同时，需要继续努力降低儿童的辐射剂量和放射检查次数，包括坚持“尽可能合理低”（ALARA）原则。
