Di Giorgio M, Edwards A A, Moquet J E, Finnon P, Hone P A, Lloyd D C, Kreiner A J, Schuff J A, Tajal M R, Vallerga M B, López F O, Burlón A, Debray M E, Valda A
Autoridad Regulatoria Nuclear, Av. Del Libertador 8250, CP: C1429BNP, Ciudad de Buenos Aires, Argentina.
Radiat Prot Dosimetry. 2004;108(1):47-53. doi: 10.1093/rpd/nch012.
Human blood was irradiated with accelerated ions: 20 MeV 4He, 425 MeV 12C and 1480 MeV and 996 MeV 16O. For each ion, the blood was exposed to a range of doses as thin specimens in the track segment mode, so that irradiations took place at nearly constant LETs of 31.4, 61, 52 and 69 keV microm(-1), respectively. Lymphocytes were cultured to the first in vitro metaphase, analysed for chromosomal damage and the dicentric aberration frequencies fitted to the linear quadratic model of dose-response. For these high LET radiations, the linear (alpha) yield coefficient predominated and increased with LET, at least up to 60 keV microm(-1). Apart from the 996 MeV oxygen ions, the data indicated the presence of a quadratic (beta) coefficient, statistically consistent with values obtained with low LET radiations. However, the associated uncertainties on the measured beta values were large, illustrating the general problem that beta is more difficult to measure against a dominating and ever-increasing alpha term. The existence or otherwise of a beta component of the dose-response at these radiation qualities has important consequences for modelling mechanisms of aberration induction by radiation.
20 MeV的4He、425 MeV的12C以及1480 MeV和996 MeV的16O。对于每种离子，血液以径迹段模式作为薄样本接受一系列剂量的辐照，使得辐照分别在31.4、61、52和69 keV·μm-1的近恒定传能线密度（LET）下进行。将淋巴细胞培养至第一次体外中期，分析染色体损伤情况，并将双着丝粒畸变频率拟合到剂量反应的线性二次模型。对于这些高LET辐射，线性（α）产额系数占主导且随LET增加，至少在高达60 keV·μm-1时如此。除了996 MeV的氧离子外，数据表明存在二次（β）系数，在统计上与低LET辐射获得的值一致。然而，测量的β值相关的不确定性很大，这说明了一个普遍问题，即相对于占主导且不断增加的α项，β更难测量。在这些辐射品质下剂量反应中β成分的存在与否对于模拟辐射诱发畸变的机制具有重要影响。
