The aim is to explore the effects of time and temperature on the generation of free radicals in fingernails exposed to ionizing radiation by drying experiment, and to view the relationship between water content in fingernails of different individuals and the growth-rate of free radical concentrations through irradiation experiment. The free radicals concentrations was measured by electron paramagnetic resonance (EPR). The results showed that the more water content fingernails contained, the more free radicals sample would generate through the same absorbed dose.Meanwhile, as absorbed dose increased, the slope of fitting curve increased with the decreasing dispersion of the data measured from fitting curve. The slopes of fitting curve of samples irradiated at 1 Gy, 5 Gy, and 10 Gy were 0.8670, 1.7425 and 1.9628, respectively. The experimental results also showed that the difference of keratin content within fingernails would probably impact free radical concentration when fingernails were exposed to ionizing radiation. The current dosimetry method needs to be revised according to the difference of water content and keratin content among individuals. By solving individual difference, the more accurate dose reconstruction would be performed.%通过干燥实验考察时间和温度对指甲在受到电离辐射时产生自由基浓度的影响;通过受照剂量实验考察人群指甲含水量与自由基浓度增长率的关系.使用电子顺磁共振方法测量指甲中的自由基浓度.实验结果表明,受照剂量相同时,不同人指甲中含水量的越多,产生的自由基越多,且随着受照剂量增大,离散程度越小,散点图拟合曲线斜率越大.受照剂量为1 Gy、5 Gy和10 Gy的样品散点图拟合曲线斜率分别为0.8670、1.7425 和 1.9628.结果还表明,受照时指甲中角蛋白的含量也会对自由基浓度产生影响.在现有的指甲电子顺磁共振受照剂量估算的基础上,需要根据样品的含水量以及角蛋白含量对结果进行修正,解决个体差异,从而得到更准确的估算结果.
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