Distribution of the radiation doses in South Urals of former Soviet Union investigated by Electron Spin Resonance dosimetry of mammal teeth

哺乳动物牙齿电子自旋共振剂量测定研究前苏联南乌拉尔地区辐射剂量分布

基本信息

批准号：
13575033
负责人：
TOYODA Shin
金额：
$ 6.02万
依托单位：
Okayama University of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

After the World War II, former Soviet Union constructed its first plant complex in South Ural, which produces plutonium, starting its operation in 1948. There were three major accidents, such as contamination of Techa river, associated with this plant complex. This region of South Ural has been contaminated with huge amount of radioactive nuclei from nuclear waste, especially with Strontium-90. Strontium replaces calcium of bones and teeth, therefore, it is taken into hydroxyapatite of tooth enamel and dentin which are examined by the present research project, giving internal doses. In the present study, 25 cow teeth from Ozersk in which the plant complex is located and from surrounding villages were examined to obtain the concentrations of Strontium-90 and radiation doses. Imaging plates sensitive to beta rays were used to obtain the concentrations. The teeth were cut in half and were placed on an imaging plate for a week in a low background lead cave. The images of the Strontium-90 distribution were obtained by the imaging scanner from the imaging plate. Quantitative measurement was available by measuring the standard samples of dentin containing known concentrations of Strontium-90. The images were found for 5 teeth of those samples. The concentrations of Strontium-90 were low in enamel but higher in the region between dentin and enamel. The maximum concentration was about 15 Bq/g. Teeth from highly contaminated area have higher Strontium-90 concentrations but with some variations. The radiation doses given to tooth enamel were measured by ESR method. Nominal doses of 300 to 400 mGy were obtained for 4 teeth samples, however, these should be considered to be tentative values because these may be overestimated due to larger background signal which is different from human teeth. Another scheme to obtain doses from cow teeth should be developed with considering the species-specific background signal.

第二次世界大战后，前苏联在南乌拉尔（South Ural）建造了首个植物综合体，该植物综合体生产了p，从1948年开始运营。发生了三起主要的事故，例如与该植物建筑群有关的Techa River污染。南乌拉尔（South Ural）地区已被核废料的大量放射性核污染，尤其是腹膜90。锶取代了骨骼和牙齿的钙，因此将其放入牙齿搪瓷和牙本质的羟基磷灰石中，这些牙釉质和牙本质由本研究项目进行了检查，给出了内部剂量。在本研究中，植物络合物所在的Ozersk的25颗牛牙被检查，并检查了周围村庄的牙齿，以获取延伸延伸的90和辐射剂量的浓度。对β射线敏感的成像板用于获得浓度。将牙齿切成两半，并在低背景铅洞中放在成像板上一周。通过成像板的成像扫描仪获得锶90分布的图像。通过测量含有已知浓度标的标的牙本质的标准样品，可以获得定量测量。这些样品的5齿发现了图像。牙釉质中锶90的浓度较低，但牙本质和搪瓷之间的区域较高。最大浓度约为15 bq/g。高度受污染区域的牙齿具有较高的90个浓度，但有些变化。通过ESR方法测量给牙齿搪瓷的辐射剂量。对于4个牙齿样品，获得了300至400 MGY的名义剂量，但是，由于较大的背景信号，它们可能被认为是暂定值，因为这些值可能被高估了，这与人牙齿不同。考虑物种特定的背景信号，应从牛牙中获得剂量的另一种方案。