亚细胞尺度氚非均匀分布下单粒子效应的蒙特卡罗模拟计算  

Monte Carlo Simulation on Single Particle Effect of Tritium Distributed Inhomogeneously in Subcellular Scale

作　　者：高晖[1] 孙亮[2] 袁永刚[1] GAO Hui;SUN Liang;YUAN Yonggang(Institute of Nuclear Physics and Chemistry,China Academy of Engineering Physics, Mianyang 621900,China;School of Radiation Medicine and Protection, Medical College of Soochow University,Suzhou 205021,China)

机构地区：[1]中国工程物理研究院核物理与化学研究所,四川绵阳621900 [2]苏州大学医学部放射医学与防护学院,江苏苏州205021

出　　处：《原子能科学技术》2018年第11期2106-2112,共7页Atomic Energy Science and Technology

摘　　要：利用蒙特卡罗程序Geant4构建了正常肺上皮细胞体素模型,结合Geant4自建DNA模型,模拟计算了氚在亚细胞尺度不同靶区的物理作用和DNA损伤效应,分析了氚处于不同滞留状态下β单粒子对细胞内环境及DNA的影响。结果表明,氚的滞留状态对不同靶区的作用呈规律性变化,源项为细胞核时,源靶组合N->N与N->C的能量沉积E_(细胞核)/E_(细胞质)比值差异最为显著,微剂量学特征值SN->N最大。β单粒子作用于DNA产生的集簇损伤尺寸一般<3,且多为简单单链断裂(SSSB)类型,尽管产生的集簇损伤尺寸≥3的比例(<5%)很低,但仍有产生集簇损伤尺寸高达6的可能。源项为细胞核时,产生双链断裂(DSB)的产额是单链断裂(SSB)的5%,其中复杂双链断裂(CDSB)约占DSB的20%,相比细胞质、细胞源项,CDSB产额最大。The physical interaction in subcellular scale targets and DNA damage effect on a voxel model of lung epithelial cell from healthy human combined with DNA model self-constructed in Geant4 were performed for tritium radiation.The influence of singleβparticle on environment in cell and DNA at different remained states of tritium was analyzed.The results show that the source distributions of tritium varying from cellular scale to subcellular scale play an important role resulting in some regular variation on irradiation effect of different targets.When the nucleus is considered as source,the energy ratio difference of nucleus and ecytoplasm for two source-target combinations between N->N and N->C is the most notable,at the same time,the S N->N as a character of microdosimetry is up to maximum.In addition,for singleβparticle of tritium,the size of cluster damage in DNA is less than 3,and the major type of cluster damage is simple single strand break(SSSB).Although the proportion of cluster damage(<5%)of cluster size more than 3 is very low,it is still possible to produce cluster of size more than 6.The yield of double-strand break(DSB)is 5%of that of single strand break(SSB),the yield of complex double-strand break(CDSB)is about 20%of that of DSB,and the yield of CDSB is maximum when the source is nucleus.

关 键 词：氚 人体肺上皮细胞 蒙特卡罗 能量沉积 集簇损伤 

分 类 号：TL72[核科学技术—辐射防护及环境保护] TL84