目的　研究不同传能线密度 (LET)的重离子1 2 C6+对体外培养的人肝癌细胞SMMC 772 1存活的影响 ,以研究人肝癌细胞对不同LET重离子的辐射敏感性。方法　用克隆形成法研究细胞的存活情况。结果　 70keV μm的细胞存活率为 1 0 % (Ds=0 .1 )和 1 % (Ds=0 .0 1 )时的吸收剂量分别为 2 94Gy和 5 88Gy ;30keV μm的Ds=0 1 和Ds =0 0 1 分别为 4 0 0Gy和 8 0 0Gy。结论　 70keV μm比 30keV μm对人肝癌细胞SMMC 772 1有更大的细胞杀死效应 Objective To investigate the effect of different ionization line density (LET) of heavy ions on the survival of human hepatocellular carcinoma cell line SMMC-772 1 in order to study the radiosensitivity of human hepatocellular carcinoma cells to different LET heavy ions. Methods Clonal formation was used to study the survival of cells. Results The absorbed doses at 70 keV μm with cell viability of 10% (Ds = 0.1) and 1% (Ds = 0.01) were 2 94 Gy and 5 88 Gy, respectively; Ds = 0 1 and Ds = 0 0 1 is respectively 4 0 0Gy and 0 0Gy. Conclusion 70 keV μm has a greater cytotoxicity effect on human hepatocellular carcinoma SMMC 772 1 than 30 keV μm