一种推广的靶效应模型及其对剂量-存活率的拟合探讨

A Generalized Target Effects Model and Fit to Dose-Survival Curves

辐射生物物理模型对于准确、有效地评估空间辐射引起的生物损伤及风险具有重要意义。目前较为流行的基于地基模拟的"靶效应模型"和"非靶效应模型",是进一步探索空间辐射生物物理模型的基础。在考虑了辐射的非靶效应和机体复杂的修复过程的基础上,将传统理论中"击中"即"失活"的线性关系进行了推广,提出了基于否定算子的靶效应模型。通过对辐射钝感和敏感的两类细胞辐射实验中剂量与细胞存活率数据进行拟合发现,对于正常皮肤成纤维细胞的存活率数据,经典的靶学说与基于否定算子的改进靶效应模型都有较好的拟合效果;而对于人类胚胎肝细胞的存活率数据,基于否定算子的改进靶效应模型的拟合结果明显优于传统的靶学说模型。拟合结果中的模型参数值在人成纤维细胞和胚胎肝细胞中明显不同,说明了本模型的参数与传能线密度,细胞的种类、以及修复能力等物理和生物因素有关。

Radiation biophysical models are of great importance for accurately and effectively assess- ing the biological damage and risk induced by space radiation. The popular radiation biophysical models, including target effect models and non-target effeet models based on the ground radiation simulations, are the foundation for the exploration of space radiation biophysical models. Consider- ing the non-target effects of radiation and the repair function of organism, we generalized the tradi- tional relationship between ＂hit＂ and ＂inactivation＂ in the classical target theory, and proposed a generalized target effects model based on negative operator. Fitting the data of radiation dose and cell survival by regression, we found that both Lea＇s target theory and the generalized target theory could give a goodness-of-fit to the data of normal skin fibroblast cells, while the latter was obviously better than the former when fitting the data of human embryonic liver cells. The modeling parameter for fitting the data of normal skin fibroblast cells was significantly different with that of human embryonic liver cells, suggesting that the model parameter depending on the negative degree between the hit and inactivation, may be related to the physical and biological factors, such as linear energy transfer, cell types, and self-repair capacity, etc.