Cucinotta F A, Wilson J W
NASA Langley Research Center, Hampton, VA 23681-0001, USA.
Radiat Environ Biophys. 1995 Aug;34(3):145-9. doi: 10.1007/BF01211540.
Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations.
太空辐射包括来自银河宇宙射线（GCR）的低水平背景成分、偶尔的高能太阳粒子事件、周期性穿过地磁捕获辐射以及可能来自机载核推进发动机的辐射。必须开发针对宇航员受此类多种成分和形式辐射的风险模型，以确保在未来美国国家航空航天局（NASA）的任务中提供充分保护。包括相对论重离子（HZE）在内的低水平背景辐射将是宇航员职业辐射的最终限制因素。我们在此考虑小鼠中的一种双突变、启动-促进、辐射致癌模型，其中启动阶段由细胞修复/错配的线性动力学模型表示，包括重离子作用截面的径迹结构模型。该模型通过与阿尔彭等人针对各种离子束的哈德腺肿瘤实验进行比较而得到验证。我们使用宇宙射线环境和重离子传输模型，将启动-促进模型应用于银河宇宙射线的辐射情况，并考虑小鼠在暴露前后的年龄以及在太空停留时间对相对风险预测的影响。我们的结果表明，与严格依赖这些辐射初始斜率估计值的模型相比，年龄依赖性辐射危害的生物物理模型将能更好地理解银河宇宙射线风险。
