Abstract

Since early April 2020, there has been intense debate over proposed clinical use of ionizing radiation to treat life-threatening pneumonia in Coronavirus Disease 2019 (COVID-19) patients. At least twelve relevant papers appeared by 20 May 2020. The radiation dose proposed for clinical trials are a single dose (0.1–1 Gy) or two doses (a few mGy followed by 0.1–0.25 Gy involving a putative adaptive response, or 1–1.5 Gy in two fractions 2–3 days apart). The scientific rationale for such proposed so-called low dose radiotherapy (LDRT) is twofold (note that only doses below 0.1 Gy are considered as low doses in the field of radiation protection, but here we follow the term as conventionally used in the field of radiation oncology). Firstly, the potentially positive observations in human case series and biological studies in rodent models on viral or bacterial pneumonia that were conducted in the pre-antibiotic era. Secondly, the potential anti-inflammatory properties of LDRT, which have been seen when LDRT is applied locally to subacute degenerative joint diseases, mainly in Germany. However, the human and animal studies cited as supportive evidence have significant limitations, and whether LDRT produces anti-inflammatory effects in the inflamed lung or exacerbates ongoing COVID-19 damage remains unclear. Therefore, we conclude that the available scientific evidence does not justify clinical trials of LDRT for COVID-19 pneumonia, with unknown benefit and known mortality risks from radiogenic cancer and circulatory disease. Despite the significant uncertainties in these proposals, some clinical trials are ongoing and planned. This paper gives an overview of current situations surrounding LDRT for COVID-19 pneumonia.

摘要

自2020年4月上旬以来，关于在2019年冠状病毒病（COVID-19）患者中使用电离辐射治疗威胁生命的肺炎的拟议临床应用引起了激烈的争论。到2020年5月20日，至少有12篇相关论文发表。为临床试验建议的辐射剂量是单剂量（0.1–1 Gy）或两剂量（几mGy，然后是0.1–0.25 Gy，涉及公认的适应性反应，或1–两次（相隔2至3天）的时间分别为1.5 Gy）。此类提议的所谓低剂量放射治疗（LDRT）的科学原理是双重的（请注意，在放射防护领域，只有低于0.1 Gy的剂量才被视为低剂量，但是在此，我们沿用常规的术语“低剂量放射治疗”）。放射肿瘤学）。首先，在抗生素前时代进行的人类病例系列和啮齿动物病毒或细菌性肺炎模型生物学研究中潜在的积极观察。其次，LDRT的潜在抗炎特性，主要是在德国，当将LDRT局部应用于亚急性退行性关节疾病时就已经看到。然而，被引用为支持性证据的人和动物研究具有明显的局限性，尚不清楚LDRT是否在发炎的肺中产生抗炎作用或加剧正在进行的COVID-19损伤。因此，我们得出结论，现有的科学证据不能证明LDRT用于COVID-19肺炎的临床试验是合理的，其益处不明，并且已知放射源性癌症和循环系统疾病造成的死亡风险。尽管这些建议存在很大的不确定性，一些临床试验正在进行和计划中。本文概述了用于COVID-19肺炎的LDRT的现状。