LET and Ion Species Dependence for Cell Killing in Normal Human Skin Fibroblasts
LET and Ion Species Dependence for Cell Killing in Normal Human Skin Fibroblasts
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DOI：
10.1667/rr3360
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发表时间：
2005-05
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影响因子：
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通讯作者：
C. Tsuruoka;Masao Suzuki;T. Kanai;K. Fujitaka
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文献类型：
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作者：
C. Tsuruoka;Masao Suzuki;T. Kanai;K. Fujitaka
摘要 Tsuruoka, C.、Suzuki, M.、Kanai, T. 和 Fujitaka, K. LET 以及正常人皮肤成纤维细胞杀伤的离子种类依赖性。辐射。资源。 163, 494–500 (2005)。我们研究了 RBE 杀伤细胞的 LET 和离子种类依赖性，以阐明不同离子的不同能量沉积导致的轨道结构差异所引起的生物效应差异。正常人体皮肤成纤维细胞接受日本国立放射线科学研究所 (NIRS) 千叶重离子医疗加速器 (HIMAC) 产生的碳、氖、硅和铁离子等重离子束照射。使用集落形成测定将细胞杀伤测量为生殖细胞死亡。碳离子和其他离子的 RBE-LET 曲线不同。碳离子的曲线急剧增加至 98 keV/μm 左右。 98 keV/μm 下碳离子的 RBE 为 4.07。相比之下，氖、硅和铁离子的曲线在180 keV/μm附近有最大峰，峰位置的RBE范围为3.03至3.39。当 RBE 被绘制为 Z*2/β2（其中 Z* 是有效电荷，β 是离子的相对速度）而不是 LET 的函数时，不同离子束的 RBE-LET 曲线之间的差异减少了，但 RBE-Z*2/β2 曲线的分支仍然存在。当失活截面被绘制为 LET 或 Z*2/β2 的函数时，它随着 LET 的增加而增加。然而，失活横截面总是小于几何横截面。这些结果表明不同离子源能量沉积轨迹结构的差异对细胞杀伤有影响。
Abstract Tsuruoka, C., Suzuki, M., Kanai, T. and Fujitaka, K. LET and Ion Species Dependence for Cell Killing in Normal Human Skin Fibroblasts. Radiat. Res. 163, 494–500 (2005). We studied the LET and ion species dependence of the RBE for cell killing to clarify the differences in the biological effects caused by the differences in the track structure that result from the different energy depositions for different ions. Normal human skin fibroblasts were irradiated with heavy-ion beams such as carbon, neon, silicon and iron ions that were generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Science (NIRS) in Japan. Cell killing was measured as reproductive cell death using a colony formation assay. The RBE-LET curves were different for carbon ions and for the other ions. The curve for carbon ions increased steeply up to around 98 keV/μm. The RBE of carbon ions at 98 keV/μm was 4.07. In contrast, the curves for neon, silicon and iron ions had maximum peaks around 180 keV/μm, and the RBEs at the peak position ranged from 3.03 to 3.39. When the RBEs were plotted as a function of Z*2/β2 (where Z* is the effective charge and β is the relative velocity of the ion) instead of LET, the discrepancies between the RBE-LET curves for the different ion beams were reduced, but branching of the RBE-Z*2/β2 curves still remained. When the inactivation cross section was plotted as a function of either LET or Z*2/β2, it increased with increasing LET. However, the inactivation cross section was always smaller than the geometrical cross section. These results suggest that the differences in the energy deposition track structures of the different ion sources have an effect on cell killing.