仓鼠V79细胞对加速碳离子的辐照致死效应

KILLING EFFECT OF CHINESE HAMSTER V79 CELLS EXPOSED TO ACCELERATED CARBON IONS

分别测定了传能线密度（LET）为125．5、200、700keV／μm碳离子辐照仓鼠V79细胞的存活曲线，由存活曲线确定了上述3种碳离子辐照时V79细胞的失活截面依次为7．86±0．17、10．44±1．11、32．32±3．58μm2。以V79细胞对60Coγ射线的存活响应为参考值，给出了对应于上述3种碳离子照射周％、20％、50％、80％存活水平下的相对生物学效应（RBE），结果表明125．5keV／μm碳离子的RBE值在各个存活水平下都为最大。提示：以存活为生物学终点的RBE最大值在LET值小于200keV／μm的碳离子辐照时出现。

Survival curves of Chinese hamster V79 cells exposed to accelerated carbon ions with linear energy transfers (LET) of 125.5, 200 and 700keV/μm were measured, respectively.Inactivation cross sections corresponding to the irradiation above were deduced from the survival curves of exposed V79 cells. They are 7.86±0.17, 10.44±1.11 and 32.32±3.58μm2, respectively in turn. With the survival response of V79 cells to 60Co γ rays as a reference value, relatively biological effectiveness (RBE) at 10%, 20%, 50% and 80% survival levels were given for the carbon ions. The results show that carbon ions with LET of 125.5keV/μm have higher values of RBE at any survival levels than others. It prompted that the maximum value of RBE for V79 cell surviving as the biological endpoint appears at the LET below 200 keV/μm for carbon ions.