Schmid E, Wagner F M, Canella L, Romm H, Schmid T E
Department for Anatomy and Cell Biology, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
Radiat Environ Biophys. 2013 Mar;52(1):113-21. doi: 10.1007/s00411-012-0449-2. Epub 2012 Dec 23.
The induction of chromosome aberrations in human lymphocytes irradiated in vitro with slow neutrons was examined to assess the maximum low-dose RBE (RBE(M)) relative to (60)Co γ-rays. For the blood irradiations, cold neutron beam available at the prompt gamma activation analysis facility at the Munich research reactor FRM II was used. The given flux of cold neutrons can be converted into a thermally equivalent one. Since blood was taken from the same donor whose blood had been used for previous irradiation experiments using widely varying neutron energies, the greatest possible accuracy was available for such an estimation of the RBE(M) avoiding the inter-individual variations or differences in methodology usually associated with inter-laboratory comparisons. The magnitude of the coefficient α of the linear dose-response relationship (α = 0.400 ± 0.018 Gy(-1)) and the derived RBE(M) of 36.4 ± 13.3 obtained for the production of dicentrics by thermal neutrons confirm our earlier observations of a strong decrease in α and RBE(M) with decreasing neutron energy lower than 0.385 MeV (RBE(M) = 94.4 ± 38.9). The magnitude of the presently estimated RBE(M) of thermal neutrons is-with some restrictions-not significantly different to previously reported RBE(M) values of two laboratories.
为评估相对于钴-60γ射线的最大低剂量相对生物效应（RBE(M)），对体外受慢中子照射的人淋巴细胞中染色体畸变的诱导情况进行了研究。对于血液照射，使用了慕尼黑研究堆FRM II的瞬发γ活化分析设施中可用的冷中子束。给定的冷中子通量可转换为热等效通量。由于血液取自同一位捐赠者，其血液曾用于先前使用广泛不同中子能量的照射实验，因此在估算RBE(M)时可获得尽可能高的准确度，避免了通常与实验室间比较相关的个体间差异或方法学差异。热中子产生双着丝粒的线性剂量反应关系系数α的大小（α = 0.400 ± 0.018 Gy⁻¹）以及由此得出的RBE(M)为36.4 ± 13.3，证实了我们早期的观察结果，即随着中子能量降低至低于0.385 MeV（RBE(M) = 94.4 ± 38.9），α和RBE(M)会大幅下降。目前估算的热中子RBE(M)大小在一定限制条件下与先前两个实验室报告的RBE(M)值无显著差异。
