Vandevoorde C, Franck C, Bacher K, Breysem L, Smet M H, Ernst C, De Backer A, Van De Moortele K, Smeets P, Thierens H
Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, 9000, Gent, Belgium,
Eur Radiol. 2015 Mar;25(3):800-11. doi: 10.1007/s00330-014-3463-8. Epub 2014 Oct 30.
Investigation of DNA damage induced by CT x-rays in paediatric patients versus patient dose in a multicentre setting.
From 51 paediatric patients (median age, 3.8 years) who underwent an abdomen or chest CT examination in one of the five participating radiology departments, blood samples were taken before and shortly after the examination. DNA damage was estimated by scoring γ-H2AX foci in peripheral blood T lymphocytes. Patient-specific organ and tissue doses were calculated with a validated Monte Carlo program. Individual lifetime attributable risks (LAR) for cancer incidence and mortality were estimated according to the BEIR VII risk models.
Despite the low CT doses, a median increase of 0.13 γ-H2AX foci/cell was observed. Plotting the induced γ-H2AX foci versus blood dose indicated a low-dose hypersensitivity, supported also by an in vitro dose-response study. Differences in dose levels between radiology centres were reflected in differences in DNA damage. LAR of cancer mortality for the paediatric chest CT and abdomen CT cohort was 0.08 and 0.13 ‰ respectively.
CT x-rays induce DNA damage in paediatric patients even at low doses and the level of DNA damage is reduced by application of more effective CT dose reduction techniques and paediatric protocols. .
在多中心环境中，研究儿科患者中CT X射线诱导的DNA损伤与患者剂量之间的关系。
从在五个参与研究的放射科之一接受腹部或胸部CT检查的51名儿科患者（中位年龄3.8岁）中，在检查前和检查后不久采集血样。通过对外周血T淋巴细胞中的γ-H2AX病灶进行评分来估计DNA损伤。使用经过验证的蒙特卡罗程序计算患者特定的器官和组织剂量。根据BEIR VII风险模型估计癌症发病率和死亡率的个体终生归因风险（LAR）。
尽管CT剂量较低，但观察到γ-H2AX病灶/细胞中位数增加了0.13。将诱导的γ-H2AX病灶与血液剂量作图表明存在低剂量超敏反应，体外剂量反应研究也支持这一点。放射科中心之间剂量水平的差异反映在DNA损伤的差异上。儿科胸部CT和腹部CT队列的癌症死亡LAR分别为0.08‰和0.13‰。
即使在低剂量下，CT X射线也会在儿科患者中诱导DNA损伤，并且通过应用更有效的CT剂量降低技术和儿科方案可以降低DNA损伤水平。
