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The study of the absorbed dose and the biological effects caused by radiation from environmental radon

环境氡辐射吸收剂量及生物效应研究

基本信息

批准号：
11672230
负责人：
HOMMA Yoshio
金额：
$ 1.02万
依托单位：
Kyoritsu College of Pharmacy
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

1. X-ray irradiation To evaluate the biological effects of environmental radiation, two groups of rats were irradiated with X-ray (31 keV). The first group was irradiated with the main X-ray and the second group was preliminarily irradiated with low-level X-ray, then, irradiated with the main X-ray again. The absorbed dose for the main X-ray irradiation was 0.5 Gy / rat, and for the preliminarily X-ray irradiation was 0.09 Gy/rat.After the main X-ray irradiation, the SOD activity of rat's liver and spleen was measured by the nitrite method for both groups, which increased to 27% higher than its normal level at 6h after X-ray irradiation, and reduced to its normal level.It is noted that, after X-ray irradiation, the SOD activity of the first group temporarily reduced to 15% lower than its normal level, although it increased again as described above. It must be emphasized that there was no reduction of the SOD activity of the second group after the main X-ray irradiation. It seems to show the important significance of the preliminary low-level X-ray irradiation.2. Environmental ^<222>Rn. The rapid method for preparing known amounts of ^<222>Rn was developed and the mouse was exposed to ^<222>Rn for 48h. The lung of the mouse was measured with a Ge spectrometer, and the gamma-emitting daughter of ^<222>Rn, that is, ^<214>Bi on the lung was determined. During 3.5h, ^<222>Rn and its daughters came to transient equilibrium and all of these nuclides have the same radioactivity. Thus, absorbed dose due to ^<222>Rn was estimated. Since a detailed investigation of low-level radiation exposure might lead to a better understanding of the mechanisms of the radiation hormesis, the authors developed the method for determining the environmental ^<222>Rn. Based on the results, the experiment to evaluate the biological effects due to the environmental ^<222>Rn is underway.

1.为了评价环境辐射的生物效应，用X射线（31 keV）照射两组大鼠。第一组用主X线照射，第二组先用低强度X线照射，然后再用主X线照射。X线主照射吸收剂量为0.5戈伊/只，X线初照射吸收剂量为0.09戈伊/只。X线主照射后，用亚硝酸盐法测定两组大鼠肝、脾SOD活性，X线照射后6 h，SOD活性均升高至正常水平的27%，随后又降至正常水平。在X射线照射后，第一组的SOD活性暂时降低到比其正常水平低15%，尽管如上所述它又增加了。必须强调的是，在主X射线照射后，第二组的SOD活性没有降低。这似乎表明了初步的低水平X射线照射的重要意义.环境^<222>Rn.开发了快速制备已知量^ Rn的方法<222>，并将小鼠暴露于^<222>Rn 48小时。用Ge光谱仪测量小鼠的肺，并确定肺上的^ Rn的γ发射子体<222>，即^<214>Bi。在3.5h内，~<222>（13）Rn及其子体达到瞬态平衡，且各核素的放射性活度相同。因此，估算了由^ Rn引起的吸收剂量<222>。由于对低水平辐射暴露的详细调查可能会导致更好地理解辐射激效效应的机制，作者开发了用于确定环境^ Rn的方法<222>。根据这些结果，正在进行评估环境中的氡对生物的影响的实验<222>。