Darmstadt University of Technology, Radiation Biology and DNA Repair, Schnittspahnstrasse 13, 64287 Darmstadt, Germany.
Radiology. 2009 Dec;253(3):706-14. doi: 10.1148/radiol.2533090468. Epub 2009 Sep 29.
To assess the effect of iodinated contrast medium (CM) on the induction and repair of DNA double-strand breaks (DSBs) in peripheral blood lymphocytes after computed tomographic (CT) examinations.
This prospective study was approved by the institutional ethics committee; written informed patient consent was obtained from 37 patients. Venous blood samples were taken from patients before and at 30 minutes, 1 hour, 2.5 hours, and 5 hours after performing CT with (n = 18) or without (n = 19) intravenous administration of CM (iopromide or iomeprol). DSBs were assessed in lymphocytes by enumerating gammaH2AX foci. DSB levels after CT were compared with those obtained after in vitro irradiation. Cell culture experiments with peripheral lymphocytes and fibroblasts were performed with iopromide, iomeprol, or the control substance mannitol added before or immediately after x- or gamma-ray irradiation. DSBs were assessed at 5 minutes, 30 minutes, 2.5 hours, and 5 hours after irradiation. Data were analyzed by using linear regression and the one-tailed Welch and paired sample t tests.
The presence of CM during CT increases DSB levels in peripheral lymphocytes by approximately 30%. Cell culture experiments confirmed this effect and further showed that CM administered prior to x-ray irradiation increases the initial DSB yield but has no effect if added after irradiation or when gamma-rays are used instead of x-rays.
The highly sensitive gammaH2AX foci assay shows that CM-enhanced radiation damage incurred in peripheral lymphocytes during CT. However, it is unknown whether long-term bioeffects of low-dose ionizing radiation from CT examinations, such as cancer, are increased by using CM.
评估计算机断层扫描（CT）检查前后碘对比剂（CM）对周围血淋巴细胞中 DNA 双链断裂（DSB）的诱导和修复的影响。
本前瞻性研究获得机构伦理委员会批准；从 37 例患者中获得静脉血样本，在进行 CT 检查前（n=18）和检查后 30 分钟、1 小时、2.5 小时和 5 小时（n=19）采集静脉血样本。通过检测γH2AX 焦点来评估淋巴细胞中的 DSB。将 CT 后 DSB 水平与体外照射后获得的水平进行比较。用添加了碘普罗胺、碘美普尔或对照物质甘露醇的外周血淋巴细胞和成纤维细胞进行细胞培养实验，分别在 X 或γ射线照射前或照射后立即添加。在照射后 5 分钟、30 分钟、2.5 小时和 5 小时评估 DSB。通过线性回归和单侧 Welch 和配对样本 t 检验分析数据。
CT 期间存在 CM 会使外周血淋巴细胞中的 DSB 水平增加约 30%。细胞培养实验证实了这一效应，并进一步表明，在 X 射线照射前给予 CM 会增加初始 DSB 产量，但如果在照射后添加或使用γ射线而不是 X 射线，则没有影响。
高度敏感的γH2AX 焦点检测法显示，CM 增强了 CT 期间外周血淋巴细胞中的辐射损伤。然而，目前尚不清楚 CT 检查中来自低剂量电离辐射的长期生物效应（如癌症）是否会因使用 CM 而增加。
