Stepanenko V F, Voillequé P G, Gavrilin Yu I, Khrouch V T, Shinkarev S M, Orlov M Yu, Kondrashov A E, Petin D V, Iaskova E K, Tsyb A F
Medical Radiological Research Center, Russian Academy of Medical Sciences, 4 Korolev Street, Obninsk, 249020, Russian Federation.
Radiat Prot Dosimetry. 2004;108(2):143-60. doi: 10.1093/rpd/nch017.
Following the Chernobyl accident, radioactive fission products, including (131)I and (137)Cs, were deposited in Bryansk Oblast in Russia. Intakes of radioiodines, mainly (131)I in milk, were the principal sources of radiation doses to thyroids of residents of the contaminated areas, but those radionuclides decayed before detailed contamination surveys could be performed. As a result, (137)Cs deposition density is the primary measure of the contamination due to the accident and there are relatively few measurements of the ratio of (131)I to (137)Cs in vegetation or soil samples from this area. Although many measurements of radiation emitted from the necks of residents were performed and used to estimate thyroidal (131)I activities and thyroid doses, such data are not available for all subjects. The semi-empirical model was selected to provide a dose calculation method to be applied uniformly to cases and controls in the study. The model was developed using dose estimates from direct measurements of (131)I in adult thyroids, and relates settlement average thyroid doses to (137)Cs contamination levels and ratios of (131)I to (137)Cs. This model is useful for areas where thyroid monitoring was not performed and can be used to estimate doses to exposed individuals. For application to children in this study, adjustment factors are used to address differences in age-dependent intake rates and thyroid dosimetry. Other individual dietary factors and sources (private/public) of milk consumed are reflected in the dose estimates. Countermeasures that reduced thyroid dose, such as cessation of milk consumption and intake of stable iodine, are also considered for each subject. The necessary personal information of subjects was obtained by interview, most frequently of their mothers, using a questionnaire developed for the study. Uncertainties in thyroid dose, estimated using Monte Carlo techniques, are presented for reference conditions. Thyroid dose estimates for individual children made using the semi-empirical model and questionnaire data compare reasonably well with dose estimates made for 19 children whose thyroid burdens of (131)I were measured from May to June 1986.
切尔诺贝利事故之后，包括碘-131和铯-137在内的放射性裂变产物沉降到了俄罗斯的布良斯克州。放射性碘的摄入，主要是牛奶中的碘-131，是污染地区居民甲状腺辐射剂量的主要来源，但这些放射性核素在能够进行详细污染调查之前就已经衰变。因此，铯-137的沉降密度是此次事故造成污染的主要衡量指标，而该地区植被或土壤样本中碘-131与铯-137的比率测量相对较少。尽管对居民颈部发出的辐射进行了许多测量，并用于估算甲状腺碘-131活度和甲状腺剂量，但并非所有受试者都有此类数据。选择了半经验模型来提供一种剂量计算方法，以便统一应用于该研究中的病例和对照。该模型是利用成年甲状腺中碘-131直接测量的剂量估算值开发的，将平均甲状腺沉降剂量与铯-137污染水平以及碘-131与铯-137的比率联系起来。该模型适用于未进行甲状腺监测的地区，可用于估算受照射个体的剂量。在本研究中应用于儿童时，使用调整因子来解决年龄依赖性摄入率和甲状腺剂量测定方面的差异。其他个体饮食因素以及所消费牛奶的来源（私人/公共）也反映在剂量估算中。对于每个受试者，还考虑了减少甲状腺剂量的对策，如停止饮用牛奶和摄入稳定碘。通过访谈，最常见的是与其母亲访谈，使用为该研究编制的问卷获取受试者必要的个人信息。给出了使用蒙特卡罗技术估算的甲状腺剂量不确定性，作为参考条件。使用半经验模型和问卷数据对个体儿童进行的甲状腺剂量估算，与1986年5月至6月测量了碘-131甲状腺负荷的19名儿童的剂量估算结果相当吻合。
