Catena C, Conti D, Del Nero A, Righi E
Divisione di Tossicologia, ENEA, CRE Casaccia, Roma.
Med Lav. 1993 Mar-Apr;84(2):133-46.
When physical dosimetry is unavailable, the biological dosimetry of ionizing radiations is considered the best method for evaluating the individual absorbed dose. In order to apply this method, it is essential to know the dose-response relationship (calibration effect) regulating the phenomenon. The results obtained on human lymphocytes after in vitro X-ray treatment are presented. Two cytogenetic methods were used: the dicentric chromosomes assay in metaphase cells and the micronuclei assay in binucleated cells. The two were compared in order to verify the best utilization of each in the context of prevention and radioprotection. For the dicentric assay, 20 samples were treated with increasing doses of X-rays (from 0.5 to 2.0 Gy) and for the micronuclei assay, 25 samples were treated with doses from 0.1 to 4.0 Gy. The biological response was then evaluated. The data obtained were fitted by a second-grade polynomial regression. The dose-response relationship for the dicentric yield was F(dic) = 0.01-0.2D + 0.091D2 (regression coefficient better than 0.95); for the micronuclei yield, it was F(mn) = 0.015 + 0.043D + 0.083D2 (regression coefficient better than 0.97). The absorbed dose in exposed individuals was evaluated by the micronuclei frequency using a mathematical process (inverse prediction) that takes into account the measurement error and the 95% confidence intervals of the calibration curve. For this purpose a programme in Basic (DOSIME) was generated that was capable of estimating the dose and its variability. Since the micronuclei assay is simple and quick to carry out, it permits extensive screening and facilitates the identification of radiosensitive subjects. The estimated dose values of individuals submitted to radiotherapy are also given.
当无法进行物理剂量测定时，电离辐射的生物剂量测定被认为是评估个体吸收剂量的最佳方法。为了应用该方法，了解调节该现象的剂量反应关系（校准效应）至关重要。本文展示了体外X射线照射后人淋巴细胞的实验结果。使用了两种细胞遗传学方法：中期细胞中的双着丝粒染色体分析和双核细胞中的微核分析。对这两种方法进行了比较，以验证它们在预防和辐射防护方面的最佳应用。对于双着丝粒分析，用递增剂量的X射线（从0.5到2.0 Gy）处理20个样本；对于微核分析，用0.1到4.0 Gy的剂量处理25个样本。然后评估生物反应。所得数据用二级多项式回归拟合。双着丝粒产率的剂量反应关系为F(dic)=0.01 - 0.2D + 0.091D²（回归系数优于0.95）；微核产率的剂量反应关系为F(mn)=0.015 + 0.043D + 0.083D²（回归系数优于0.97）。通过微核频率，采用考虑测量误差和校准曲线95%置信区间的数学过程（反向预测）来评估受照个体的吸收剂量。为此编写了一个Basic程序（DOSIME），它能够估计剂量及其变异性。由于微核分析操作简单快捷，因此可进行广泛筛查并有助于识别辐射敏感个体。还给出了接受放射治疗个体的估计剂量值。
