干旱地区核设施周围陆生昆虫—蒙古束颈蝗剂量系数估算

Dose coefficient estimation for terrestrial Sphingonotus insects near nuclear facilities in Northwest China

为了研究我国干旱地区核设施附近代表性生物剂量系数,以蒙古束颈蝗(Splingonotus mongolicus Saussure)为例,基于解剖学和几何学建立简化解剖学模型和基于CT断层扫描、Photoshop软件及Python编程等建立体素模型,并分别计算环境介质中^(90)Sr、^(137)Cs对蒙古束颈蝗不同组织和器官的内外照射剂量系数。为了验证本次计算结果的可行性,将计算结果与ICRP 108号报告进行了比较。由于ICRP 108号出版物采用整体简化模型,因此本文计算结果采用各个器官剂量系数总体平均值。结果显示:^(90)Sr对蒙古束颈蝗简化解剖学模型内外照射剂量系数分别为6.59×10^(−4)μGyh^(−1)/Bqkg^(−1)、6.74×10^(−4)μGyh^(−1)/Bqkg^(−1);^(137)Cs对蒙古束颈蝗简化解剖学模型内外照射剂量系数分别为1.34×10^(−4)μGyh^(−1)/Bqkg^(−1)、4.40×10^(−3)μGyh^(−1)/Bqkg^(−1);^(90)Sr对蒙古束颈蝗体素模型内外照射剂量系数分别为7.87×10^(−4)μGyh^(−1)/Bqkg^(−1)、6.74×10^(−4)μGyh^(−1)/Bqkg^(−1);^(137)Cs对蒙古束颈蝗体素模型内外照射剂量系数分别为1.33×10^(−4)μGyh^(−1)/Bqkg^(−1)、3.51×10^(−3)μGyh^(−1)/Bqkg^(−1);ICRP 108号出版物中提供的^(90)Sr对参考昆虫的内外照射剂量系数分别为1.00×10^(−2)μGyh^(−1)/Bqkg^(−1)、3.^(90)×10−10μGyh^(−1)/Bqkg^(−1);ICRP 108号出版物中提供的^(137)Cs对参考昆虫的内外照射剂量系数分别为3.20×10^(−3)μGyh^(−1)/Bqkg^(−1)、2.80×10^(−3)μGyh^(−1)/Bqkg^(−1)。根据以上数据比较,ICRP 108号报告中提供的内照射剂量系数均比本文建立的剂量学模型计算结果大,外照射剂量系数均小,这可能与生物的体型及采用放射性核素衰变粒子及能量有关。本文采用接近生物体形态的简化解剖学模型及与生物体高度重合的体素模型,更加接近于生物体真实受照情况,精确度高、误差小,证明本次建立的昆虫剂量学模型可行。

To study the representative dose coefficients near nuclear facilities in the arid regions of Northwest China,a simplified anatomical model of Sphingonotus insects using computed tomography(CT)scanning is proposed.In addition,a voxel model created by using Photoshop and Python is used to assess the results of the simplified anatomical model.The dose coefficients of internal and external^(90)Sr and^(137)Cs irradiation on different organs of Sphingonotus insects in the environmental medium are calculated.To verify the feasibility of the proposed model,the results are compared with the dose coefficients reported in the International Commission on Radiological Protection(ICRP)Publication 108.Based on the simplified model adopted by ICRP to arrive at the results reported in Publication 108,the average value of dose coefficients of each organ of the insect is used to calculate the results presented in this paper.The dose coefficients of internal and external^(90)Sr irradiation for the simplified anatomical model of Sphingonotus were found to be 6.59×10^(−4)μGyh^(−1)/Bqkg^(−1)and 6.74×10^(−4)μGyh^(−1)/Bqkg^(−1),respectively.Meanwhile,the dose coefficients of internal and external^(137)Cs irradiation for the simplified anatomical model were 1.34×10^(−4)μGyh^(−1)/Bqkg^(−1)and 4.40×10^(−3)μGyh^(−1)/Bqkg^(−1),respectively.The dose coefficients were 7.87×10^(−4)μGyh^(−1)/Bqkg^(−1)and 6.74×10^(−4)μGyh^(−1)/Bqkg^(−1),respectively.The dose coefficients were 1.33×10^(−4)μGyh^(−1)/Bqkg^(−1)and 3.51×10^(−3)μGyh^(−1)/Bqkg^(−1),respectively.The dose coefficients of internal and external^(90)Sr radiation for reference insects as reported in the ICRP Publication 108 were 1.00×10^(−2)μGyh^(−1)/Bqkg^(−1)and 3.^(90)×10−10μGyh^(−1)/Bqkg^(−1),respectively.Moreover,the dose coefficients of internal and external^(137)Cs radiation in the ICRP Publication 108 were 3.20×10^(−3)μGyh^(−1)/Bqkg^(−1)and 2.80×10^(−3)μGyh^(−1)/Bqkg^(−1),respectively.The above data indicate that the dose coefficients of internal irradiation reported in the ICRP Publication 108 are larger than those calculated using the proposed dosiological model,whereas those of external irradiation in ICRP Publication 108 are smaller.This trend is probably related to the size of the organism,decay rate,and energy of radionuclides.The adoption of a simplified anatomical model,morphologically similar to the organism,and a voxel model,highly overlapping with the organism,in this study allows a visualization of the real exposure situation for the organism considered with high accuracy,proving the feasibility of the insect dosimetry model established in this study.