Cygler J, Klassen N V, Ross C K, Bichay T J, Raaphorst G P
Ottawa Regional Cancer Centre, Civic Division, Ontario, Canada.
Radiat Res. 1994 Oct;140(1):79-84.
This in vitro study was undertaken to determine if ultrahigh dose rates could improve the radiation response of human tumors. Two cell lines, human glioma (U-87 MG), which is radioresistant, and human melanoma (HT-144), which is radiosensitive, were irradiated at ultrahigh and high dose rates under aerobic and anoxic conditions to determine if their oxygen enhancement ratios are modified by dose rate. In fact, the survival curves, and hence the oxygen enhancement ratios, were found to be independent of the dose rate. The oxygen enhancement ratio for glioma cells irradiated in plateau phase was 2.8 (+/- 0.3). The oxygen enhancement ratio was 2.7 (+/- 0.4) for melanoma cells in plateau phase and 2.8 (+/- 0.3) in exponential phase. These results indicate that there is no advantage in treating these tumors using ultrahigh dose rates instead of conventional dose rates.
进行这项体外研究是为了确定超高剂量率是否能改善人类肿瘤的辐射反应。在有氧和缺氧条件下，以超高和高剂量率对两种细胞系进行照射，一种是具有放射抗性的人类胶质瘤（U-87 MG）细胞系，另一种是具有放射敏感性的人类黑色素瘤（HT-144）细胞系，以确定剂量率是否会改变它们的氧增强比。事实上，发现存活曲线以及氧增强比与剂量率无关。处于平台期的胶质瘤细胞的氧增强比为2.8（±0.3）。处于平台期的黑色素瘤细胞的氧增强比为2.7（±0.4），处于指数期的为2.8（±0.3）。这些结果表明，使用超高剂量率而非传统剂量率治疗这些肿瘤没有优势。
