Computed tomography (CT) is a crucial element of medical imaging diagnostics. The widespread application of this technology has made CT one of the major contributors to medical radiation burden, despite the fact that doses per individual CT scan steadily decrease due to the advancement of technology. Epidemiological risk assessment of CT exposure is hampered by the fact that moderate adverse effects triggered by low doses of CT exposure are likely masked by statistical fluctuations. In light of these limitations, there is need of further insights into the biological processes induced by CT scans to complement the existing knowledge base of risk assessment. This prompted us to investigate the early transcriptomic response of ex vivo irradiated peripheral blood of three healthy individuals. Samples were irradiated employing a modern dual-source-CT-scanner with a tube voltage of 150 kV, resulting in an estimated effective dose of 9.6 mSv. RNA was isolated 1 h and 6 h after exposure, respectively, and subsequently analyzed by RNA deep sequencing. Differential gene expression analysis revealed shared upregulation of AEN, FDXR, and DDB2 6 h after exposure in all three probands. All three genes have previously been discussed as radiation responsive genes and have already been implicated in DNA damage response and cell cycle control after DNA damage. In summary, we substantiated the usefulness of AEN, FDXR, and DDB2 as RNA markers of low dose irradiation. Moreover, the upregulation of genes associated with DNA damage reminds one of the genotoxic nature of CT diagnostics even with the low doses currently applied.

中文翻译：

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CT辐射诱导的外周血细胞内基因表达的变化。

计算机断层扫描（CT）是医学成像诊断的关键要素。尽管由于技术的进步，每次个人CT扫描的剂量稳步下降，但该技术的广泛应用已使CT成为医疗辐射负担的主要贡献者之一。CT暴露的流行病学风险评估受到以下事实的阻碍：低剂量的CT暴露触发的中度不良反应可能被统计波动所掩盖。鉴于这些限制，需要对由CT扫描诱发的生物过程有进一步的了解，以补充现有的风险评估知识库。这促使我们研究了三个健康个体的离体辐射外周血的早期转录组反应。使用现代双源CT扫描仪以150 kV的管电压辐照样品，估计有效剂量为9.6 mSv。分别在暴露后1 h和6 h分离RNA，然后通过RNA深度测序进行分析。差异基因表达分析显示，在所有三个先证者暴露后6小时，AEN，FDXR和DDB2共享上调。先前已经讨论了所有三个基因作为辐射响应基因，并且已经与DNA损伤后的DNA损伤反应和细胞周期控制有关。总之，我们证实了AEN，FDXR和DDB2作为低剂量辐射的RNA标记的有用性。而且，与DNA损伤相关的基因的上调提醒了CT诊断的遗传毒性性质之一，即使目前使用的剂量很小。