Electron paramagnetic resonance in irradiated fingernails: variability of dose dependence and possibilities of initial dose assessment
Electron paramagnetic resonance in irradiated fingernails: variability of dose dependence and possibilities of initial dose assessment
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DOI：
10.1007/s00411-009-0232-1
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发表时间：
2009-08-01
影响因子：
1.7
通讯作者：
Benevides, L. A.
中科院分区：
文献类型：
--
作者：
Reyes, R. A.;Romanyukha, Alexander;Benevides, L. A.
展示了受辐射指甲的电子顺磁共振 (EPR) 测量结果。总共研究了 83 个不同指甲的样本。根据指甲样本的采集时间、机械应力水平以及剪下的数量和大小，选择了五组不同的样本：（1）最近（<24小时）切割、照射并用EPR测量的样本，没有对样本进行任何处理，并且严格控制剪下的大小和数量（应力-新鲜，受控）； (2)最近(<24小时)在应用特殊处理(水浸泡10分钟，干燥时间5分钟)后用EPR进行切割、照射和测量，以减少切割样品引起的机械应力，并严格控制剪下的尺寸和数量(无应力-新鲜，受控)； （3）预先（> 24小时）切割，室温保存，在研究前立即切成小块，辐照并用EPR测量，不对样品进行任何处理，并严格控制剪报的大小和数量（应力老，受控）； (4)预先(>24小时)切割，室温保存，在研究前立即切割成小块，在应用特殊处理后用EPR进行照射和测量，以减少切割引起的机械应力，并严格控制切割的大小和数量(无应力-旧的，受控)； （5）最近（<24小时）在应用特殊处理以减少切割引起的机械应力后用EPR进行切割、照射和测量，并且没有严格控制剪报的大小和数量（无应力-新鲜，不受控制）。除第五个选定组外，发现所有组内剂量依赖性的变异性不具有统计学显着性，尽管不同组之间的变异性显着。对每组获得的平均剂量依赖性进行比较，可以选择负责辐射敏感性（每单位质量和剂量的剂量响应）和指甲剂量依赖性形状的关键因素。指甲的含水量被认为是造成辐射敏感性的主要因素，它可影响高达 35% 的辐射敏感性。确定辐射敏感性形状的主要因素是机械应力。在显着的机械应力水平下，剂量依赖性的形状在研究的剂量范围（< 20 Gy）内呈线性，而在应力较小的样品中，它呈指数增长，包括饱和度，这取决于机械应力的程度。鉴于研究结果，讨论并提出了针对指甲 EPR 剂量测量的适当方案的建议。
The results of electron paramagnetic resonance (EPR) measurements in irradiated fingernails are presented. In total, 83 samples of different fingernails were studied. Five different groups of samples were selected based on the collection time of fingernail samples, their level of mechanical stress, and the number and size of clippings: (1) recently (< 24 h) cut, irradiated and measured with EPR without any treatment of samples, and with rigorous control of size and number of clippings (stressed-fresh, controlled); (2) recently (< 24 h) cut, irradiated and measured with EPR after application of a special treatment (10 min of water soaking, 5 min of drying time) to reduce the mechanical stress caused by cutting the samples, and with rigorous control of size and number of clippings (unstressed-fresh, controlled); (3) previously (> 24 h) cut, stored at room temperature, additionally cut into small pieces immediately prior to study, irradiated and measured with EPR without any treatment of samples, and with rigorous control of size and number of clippings (stressed-old, controlled); (4) previously (> 24 h) cut, stored at room temperature, additionally cut into small pieces immediately prior to the study, irradiated and measured with EPR after application of a special treatment to reduce mechanical stress caused by cut, and with rigorous control of size and number of clippings (unstressed-old, controlled); and (5) recently (< 24 h) cut, irradiated and measured with EPR after application of a special treatment to reduce the mechanical stress caused by cut, and without rigorous control of size and number of clippings (unstressed-fresh, uncontrolled). Except for the fifth selected group, variability of the dose dependence inside all groups was found to be not statistically significant, although the variability among the different groups was significant. Comparison of the mean dose dependences obtained for each group allowed selection of key factors responsible for radiation sensitivity (dose response per unit of mass and dose) and the shape of dose dependence in fingernails. The major factor responsible for radiation sensitivity of fingernails was identified as their water content, which can affect radiation sensitivity up to 35%. The major factor responsible for the shape of the radiation sensitivity was identified as the mechanical stress. At a significant level of mechanical stress, the shape of the dose dependence is linear in the studied dose range (< 20 Gy), and in lesser-stressed samples it is of an exponential growth including saturation, which depends on the degree of mechanical stress. In view of the findings, recommendations are discussed and presented for the appropriate protocol for EPR dose measurements in fingernails.