From the Department of Diagnostic Radiology, Graduate School of Biomedical Health Sciences, Hiroshima University, Hiroshima, Japan (H.S., W.F., K.A.); Department of Cardiovascular Physiology and Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (M.I., C.S.); Departments of Cellular Biology (L.S., S.T.) and Surgical Oncology (Y.M., M.O.), Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8553, Japan; Department of Epidemiology, Infectious Disease Control and Prevention, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.A.); and Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan (T.I.).
Radiology. 2020 May;295(2):439-445. doi: 10.1148/radiol.2020190389. Epub 2020 Mar 10.
Background Although the National Lung Screening Trial reported a significant reduction in lung cancer mortality when low-dose (LD) CT chest examinations are used for a diagnosis, their biologic effects from radiation exposure remain unclear. Purpose To compare LD CT and standard-dose (SD) CT for DNA double-strand breaks and chromosome aberrations (CAs) in peripheral blood lymphocytes. Materials and Methods Between March 2016 and June 2018, 209 participants who were referred to a respiratory surgery department for chest CT studies were prospectively enrolled in this study. Individuals were excluded if they had undergone radiography examinations within the last 3 days or had undergone chemotherapy or radiation therapy. Peripheral blood samples were obtained before and 15 minutes after CT. The number of γ-H2AX foci and unstable CAs in lymphocytes was quantified by immunofluorescent staining of γ-H2AX and by fluorescence in situ hybridization by using peptide nucleic acid probes for centromeres and telomeres, respectively. The Wilcoxon signed rank test was used for statistical analysis. Bonferroni correction was applied for multiple comparisons. Results Of the 209 participants (105 women, 104 men; mean age, 67.0 years ± 11.3 [standard deviation]), 107 underwent chest LD CT and 102 underwent chest SD CT. Sex distribution, age, and body size metrics were similar between the two groups. The median effective dose of LD CT and SD CT was 1.5 and 5.0 mSv, respectively. The number of double-strand breaks and CAs increased after a SD CT examination (γ-H2AX, < .001; CAs, = .003); the number of double-strand breaks and CAs before and after LD CT was not different (γ-H2AX, = .45; CAs, = .69). Conclusion No effect of low-dose CT on human DNA was detected. In the same setting, DNA double-strand breaks and chromosome aberrations increased after standard-dose CT. © RSNA, 2020 See also the editorial by Brenner in this issue.
背景 虽然国家肺癌筛查试验报告称，低剂量（LD）CT 胸部检查用于诊断可显著降低肺癌死亡率，但它们的辐射生物学效应仍不清楚。目的 比较 LD CT 和标准剂量（SD）CT 对外周血淋巴细胞中 DNA 双链断裂和染色体畸变（CAs）的影响。材料与方法 2016 年 3 月至 2018 年 6 月，前瞻性纳入 209 例因胸部 CT 检查而就诊于呼吸外科的患者进行此项研究。如果患者在过去 3 天内接受过射线检查或接受过化疗或放疗，则将其排除在外。在 CT 检查前和 15 分钟时采集外周血样本。用 γ-H2AX 免疫荧光染色和用肽核酸探针进行荧光原位杂交，分别定量检测淋巴细胞中的 γ-H2AX 焦点和不稳定 CA。采用 Wilcoxon 符号秩检验进行统计学分析。采用 Bonferroni 校正进行多重比较。结果 209 例患者（105 例女性，104 例男性；平均年龄 67.0 岁±11.3[标准差]）中，107 例行胸部 LD CT 检查，102 例行胸部 SD CT 检查。两组患者的性别分布、年龄和身体尺寸指标相似。LD CT 和 SD CT 的有效剂量中位数分别为 1.5 和 5.0 mSv。SD CT 检查后双链断裂和 CAs 的数量增加（γ-H2AX，<.001；CAs，=.003）；LD CT 检查前后双链断裂和 CAs 的数量无差异（γ-H2AX，=.45；CAs，=.69）。结论 在相同条件下，未检测到 LD CT 对人 DNA 的影响。标准剂量 CT 后，DNA 双链断裂和染色体畸变增加。®RSNA，2020 本期亦见 Brenner 的社论。
