Fabry L, Leonard A, Wambersie A
Radiat Res. 1985 Jul;103(1):122-34.
Human peripheral blood lymphocytes from two donors were exposed to low doses (0.05 to 2.0 Gy) of gamma rays, X rays, or fast neutrons of different energies. Chromosome aberrations were analyzed in metaphase of first-division cells after a culture time of 45-46 hr. At this time, less than 5% of the cells were found in second division. Different dose-response relationships were fitted to the data by using a maximum likelihood method; best fits for radiation-induced dicentric aberrations were obtained with the linear-quadratic law for all radiations. The linear component of this equation predominated, however, for neutrons in the range of doses studied, and the frequency of dicentrics induced by d(16)+Be neutrons up to 1.0 Gy could also be described by a linear relationship. The relative biological efficiency (RBE) of X rays and d(16)+Be, d(33)+Be, and d(50)+Be neutrons compared to 60Co gamma rays in the low dose range was calculated from the dose-effect relationships for the dicentrics produced. The RBE increased with decreasing neutron dose and with decreasing neutron energy from d(50)+Be to d(16)-+Be neutrons. The limiting RBE at low doses (RBEo) was calculated to be about 1.5 for X rays and 14.0, 6.2, and 4.7 for the d(16)+Be, d(33)+Be, and d(50)+Be neutrons, respectively.
来自两名供体的人外周血淋巴细胞暴露于低剂量（0.05至2.0 Gy）的γ射线、X射线或不同能量的快中子。在培养45 - 46小时后，对第一次分裂细胞的中期染色体畸变进行分析。此时，发现不到5%的细胞处于第二次分裂。通过使用最大似然法将不同的剂量 - 反应关系拟合到数据中；对于所有辐射，用线性 - 二次定律获得了辐射诱导双着丝粒畸变的最佳拟合。然而，在所研究的剂量范围内，该方程的线性成分对于中子占主导地位，并且高达1.0 Gy的d(16)+Be中子诱导的双着丝粒频率也可以用线性关系描述。根据产生的双着丝粒的剂量 - 效应关系，计算了低剂量范围内X射线以及d(16)+Be、d(33)+Be和d(50)+Be中子与60Coγ射线相比的相对生物效能（RBE）。RBE随着中子剂量的降低以及从中子能量d(50)+Be到d(16)-+Be的降低而增加。计算得出低剂量下的极限RBE（RBEo）对于X射线约为1.5，对于d(16)+Be、d(33)+Be和d(50)+Be中子分别为14.0、6.2和4.7。
