空间高能质子及重离子诱导的DNA损伤模拟计算  

Simulation calculation of DNA damage induced by high-energy protons and heavy ions in space

作　　者：齐婕 闫庆倩[1] QI Jie;YAN Qingqian(Department of Occupational Radiological Health,Nanjing Municipal Center for Disease Control and Prevention,Nanjing 210003,China)

机构地区：[1]南京市疾病预防控制中心职业放射卫生科,南京210003

出　　处：《核技术》2025年第3期112-122,共11页Nuclear Techniques

基　　金：南京市疾控中心青年人才科研培育团队项目(No.NPY2406)资助。

摘　　要：采用蒙特卡罗方法模拟辐射诱导DNA损伤过程,通过获得的细胞水平数字化损伤产额评估空间辐射环境生物学效应。基于空间环境中的主要辐射来源,结合蒙特卡罗损伤模拟程序(Monte Carlo Damage Simulation,MCDS),首先针对单能状态下的质子、氦离子、碳离子、氧离子、硅离子和铁离子设置了10~105 MeV不等间隔的5个能量点,同时选择典型太阳质子事件能谱以及太阳极小时和极大时银河宇宙射线中的主要粒子能谱作为辐射源项代表,分别进行了DNA双链断裂(Double Strand Breaks,DSBs)、单链断裂(Single Strand Breaks,SSBs)以及其他损伤的产额的模拟计算。在此基础上,分析了乏氧和富氧细胞环境对损伤产额及相对生物效应的影响。根据单能辐射模拟计算结果看出,随能量增加,SSBs数目逐渐增加,而DSBs数目逐渐减少;当细胞含氧量仅为2%时,103 MeV质子、氦离子、碳离子以及氧离子引起的DSBs产额比富氧条件下的结果分别减少14.23%、15.8%、14.84%和12.08%;而硅离子和铁离子引起的DSBs产额减少百分比可以忽略。在6种空间辐射粒子中,硅离子和铁离子因其原子序数更高,其相对生物效应受氧浓度影响更为明显。从太阳极大时和极小时质子能谱辐射诱导DNA损伤结果可以发现:相比于太阳极小时,太阳极大时质子能谱辐射产生的SSBs产额有所增加,而DSBs产额有所减少;对于典型的太阳质子事件,其诱导的DNA损伤产额高于银河宇宙射线中的质子辐射,在21%和2%氧含量条件下相对生物效应因子分别为1.75和1.84。本研究借助一种蒙特卡罗损伤模型评估空间高能辐射粒子在细胞水平的辐射效应,通过对DNA链断裂产额的计算,帮助了解空间辐射对人体细胞的辐射损伤特点;同时通过这一模型可以快速预测不同辐射下的相对生物效应,有利于辐射剂量学的发展并建立更好的空间辐射剂量监测模式。[Background]Space radiation is one of the main factors that cause damage to living organisms and threaten the health of astronauts during long-term manned spaceflight.Therefore,space radiation risk assessment is an important issue in astronaut radiation risk warning and protection in manned spaceflight engineering.[Purpose]This study aims to evaluate the biological effects of space radiation environment by simulating the radiation-induced DNA damage process using Monte Carlo method to digitize the damage yield at the cellular level.[Method]Firstly,based on the main radiation sources in the space environment,five energy points with intervals of 10~105 MeV for monoenergetic protons,helium ions,carbon ions,oxygen ions,silicon ions,and iron ions were set for the Monte Carlo damage simulation program(MCDS)applied to the calculation of DNA damage induced by high-energy protons and heavy ions in space.Simultaneously,typical solar proton event,as well as the main spectra in galactic cosmic rays during solar minimum and maximum,were selected as radiation sources to simulate the yields of DNA double strand breaks(DSBs),single strand breaks(SSBs),and other damages.Then,the effects of hypoxic and oxygen enriched cellular environments on damage yields and relative biological effectiveness were analyzed.[Results]Simulation results of single energy radiation show that the number of SSBs gradually increases whilst the number of DSBs gradually decreases with the increase of energy.When the cell oxygen concentration is only 2%,the yields of DSBs caused by 103 MeV protons,helium ions,carbon ions,and oxygen ions are reduced by 14.23%,15.8%,14.84%,and 12.08%,respectively,compared to the results under normoxic environment.The percentage reduction of silicon ions and iron ions can be ignored.Among the six types of monoenergetic space radiation particles,the relative biological effectiveness of silicon ions and iron ions with higher atomic numbers are more significantly affected by oxygen concentration.The results of DNA damage induced

关 键 词：空间辐射 高能粒子 DNA损伤 蒙特卡罗模拟 生物效应 

分 类 号：TL72[核科学技术—辐射防护及环境保护] R312[医药卫生—基础医学]