外照射小剂量电离辐射所致器官剂量的估算应用研究

摘要

Objective: To explore a feasible γ energy spectrum method for estimating organ doses which induced by external irradiation, and the application prospect of this method in the organ dose estimation. Methods:Analysis theγ energy spectrum which measured in high background areas of Yangjiang by Efficiency calibration without Radioactive Source method, based on the existing residents of organ dose conversion factors for estimating and analysis, and the corresponding position of the measured air kerma the effective dose estimated by comparison of the whole body. Results: Through the passive efficiency calibration method to analyze 30 organ absorbed dose and effective dose (adult males) of residents who living in the high background areas of Yangjiang and control area, including red bone marrow, colon (wall), thyroid, eye lens, etc. Residents in high background areas of the body effective dose estimates range from 1.97 mSv/a to 2.93 mSv/a, which consistent with the results and the measurement of air kerma estimate. Conclusion:The experimental design is reasonable, but also shows that the method is feasible for small doses of ionizing radiation induced organ dose estimates application.%目的：探索一种可行的γ能谱分析用于辐射流行病学调查现场常见场景情况下外照射所致器官剂量的估算方法，并展望此方法在器官剂量估算中的应用前景。方法：采用无源效率刻度方法对阳江高本底地区居民居住环境所测量的γ能谱进行分析，根据已有的转换系数对居民器官剂量进行估算和分析，并和对应位置所测量的空气比释动能所估算出来的全身有效剂量进行对比。结果：采用无源效率刻度方法，分析阳江高本底地区和对照地区居民(成年男性)包括红骨髓、结肠(壁)、甲状腺及眼晶体等30个人体器官的年器官吸收剂量和全身有效剂量。高本底地区居民全身有效剂量的估算结果(不含宇宙射线)为1.97～2.93 mSv/a，计算得到的测量点的空气比释动能和在同一测量点实测的结果相一致。结论：该实验设计方案合理，其结果可信，同时表明该方法在小剂量电离辐射所致器官剂量估算中的应用可行。