Contributions to the Study of Immediate and Early X-ray Reactions with Regard to Chemoprotection

The immediate x-ray depolymerization of the mucopolysaccharide matrix in the dermal layer of the skin, the cock's comb, the aortic wall and in thin membranes is demonstrated, and in the skin it is further analysed. Irradiation is with low doses, and measurements are made of injection pressure and of filtration rate.     

硝酸钚致大自鼠骨肉瘤的效应

本文报道了硝酸钚致大白鼠骨肉瘤的实验研究。结果表明,钚确系兵有高度致癌的毒性,在5μCl²³⁹pu/kg组中,大白鼠骨肉宿发生率为38.9%,最早发现骨肉窟的时间为注钚后294天,计算所得每戈瑞的骨肉瘟发生率为0.028。钚诱发大白鼠的骨肉瘤容易扩散到其它脏器。     

Plutonium from Above-Ground Nuclear Tests in Milk Teeth: Investigation of Placental Transfer in Children Born between 1951 and 1995 in Switzerland

Background

Occupational risks, the present nuclear threat, and the potential danger associated with nuclear power have raised concerns regarding the metabolism of plutonium in pregnant women.

Objective

We measured plutonium levels in the milk teeth of children born between 1951 and 1995 to assess the potential risk that plutonium incorporated by pregnant women might pose to the radiosensitive tissues of the fetus through placenta transfer.

Methods

We used milk teeth, whose enamel is formed during pregnancy, to investigate the transfer of plutonium from the mother’s blood plasma to the fetus. We measured plutonium using sensitive sector field inductively coupled plasma mass spectrometry techniques. We compared our results with those of a previous study on strontium-90 (⁹⁰Sr) released into the atmosphere after nuclear bomb tests.

Results

Results show that plutonium activity peaks in the milk teeth of children born about 10 years before the highest recorded levels of plutonium fallout. By contrast, ⁹⁰Sr, which is known to cross the placenta barrier, manifests differently in milk teeth, in accordance with ⁹⁰Sr fallout deposition as a function of time.

Conclusions

These findings demonstrate that plutonium found in milk teeth is caused by fallout that was inhaled around the time the milk teeth were shed and not from any accumulation during pregnancy through placenta transfer. Thus, plutonium may not represent a radiologic risk for the radiosensitive tissues of the fetus.     

Threshold for Radon-Induced Lung Cancer From Inhaled Plutonium Data

Cohen’s lung cancer mortality data, from his test of the LNT theory, do not extend to the no observed adverse effects level (NOAEL) above which inhaled radon decay products begin to induce excess lung cancer mortality. Since there is concern about the level of radon in homes, it is important to set the radon limit near the NOAEL to avoid the risk of losing a health benefit. Assuming that dogs model humans, data from a study on inhaled plutonium dioxide particulates in dogs were assessed, and the NOAEL for radon-induced lung tumors was estimated to be about 2100 Bq/m³. The US Environmental Protection Agency should consider raising its radon action level from 150 to at least 1000 Bq/m³.     

Doses and lung cancer risks from exposure to radon and plutonium

Abstract

Purpose: Epidemiological studies of the French uranium miners and the plutonium workers at the Mayak nuclear facility have provided excess relative risk (ERR) estimates per unit absorbed lung dose from alpha radiation. The aim of this paper was to review these two studies and to derive values of the relative biological effectiveness (RBE) of alpha particles for the induction of lung cancer.

Materials and methods: We examined and compared the dosimetry assumptions and methodology used in the epidemiological studies of uranium miners and the plutonium workers. Values of RBE were obtained by comparing risk coefficients including comparison of lifetime risks for a given population. To do this, preliminary calculations of lifetime risks following inhalation of plutonium were carried out.

Results and conclusions: Published values of risk per unit dose following inhalation of radon progeny and plutonium were in agreement despite the very different dose distributions within the lungs and the different ways the doses were calculated. Values of RBE around 10–20 were obtained by comparing ERR values, but with wide uncertainty ranges. Comparing lifetime risks gave similar values (10, 19 and 21). This supports the use of a radiation weighting factor of 20 for alpha particles for radiation protection purposes.     

尿钚裂变径迹分析方法与马绍尔居民钚－239内照射剂量的估算

作者介绍了尿钚裂变径迹分析法（简称ＦＴＡ），剂量评估的现代资料，总结了１９８１年～１９９１年中Ｒｏｎｇｅｌａｐ和Ｕｔｉｒｉｋ岛居民钚－２３９内照剂量估算的结果。目前ＦＴＡ钚－２３９的探测水平（９９％）为２～３μＢｑ，这相当于马绍尔居民到７０岁时，０．２～０．３ｍＳｖ的有效剂量当量（ＥＤＥ）。大多数样品均低于该探测水平。１９９１年，由于少数几个高数据，使平均值偏高，因而Ｒｏｎｇｅｌａｐ和Ｕｔｉｒｉｋ岛居民的钚－２３９平均有效剂量当量估计为０．６２和１．６ｍＳｖ。这是自从１９８８年以来的最高值。     

非规范案例的辐射致癌病因概率计算──一例钚内污染工人肘部恶性纤维组织细胞瘤的病因判断

结合一例钚内污染人员所患肘部恶性纤维组织细胞瘤的辐射病因判断，提出非规范病例辐射致癌病因概率（ＰＣ）计算方法，作为示范。根据肿瘤的组织结构提出三种可能的靶细胞。通过现有剂量监测数据计算三种靶细胞的照射剂量。再利用间接导出的相应的致癌超额相对危险系数计算肿瘤来自所受照射的病因概率。其结果因所选用的靶细胞、危险系数和计算模型而有根大不同，最大相差４个量级。由于这个病例情况比较复杂，因此作者提出的计算步骤可供计算其它非规范病例ＰＣ参考。本文作者还结合国内、外钚内污染人员的医学观察经验对钚致癌的可能性进行讨论。