Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University, SE 17176, Stockholm, Sweden.
Radiat Res. 2010 Oct;174(4):517-25. doi: 10.1667/RR2045.1.
In light-ion radiation therapy, both the dose and the local energy spectrum, which is often characterized with the linear energy transfer (LET), must be considered. In treatment optimization, it is advantageous to use a radiobiological model that analytically accounts for both dose and LET for the ion type of interest. With such a model the biological effect can also be estimated for dose and LET combinations for which there are no observations in the underlying experimental data. In this study, the repairable-conditionally repairable (RCR) damage model was extended by expressing its parameters as functions of LET to provide a radiobiological model that accounts for both the dose and the LET for a given ion type and cell line. This LET-parameterized RCR model was fitted to published cell survival data for HSG and V79 cells irradiated with carbon ions and for T1 cells irradiated with helium ions. To test the robustness of the model, fittings to only a subset of the data were performed. Good agreement with the cell survival data was obtained, including survival data for LET values not used for model fitting, opening up the possibility of using the model in treatment planning for light ions.
在轻离子放射治疗中，必须考虑剂量和局部能量谱，后者通常以线性能量传递 (LET) 来表示。在治疗优化中，使用能够分析剂量和感兴趣离子类型的 LET 的放射生物学模型是有利的。使用这样的模型，即使在基础实验数据中没有观察到剂量和 LET 组合的情况下，也可以估计生物效应。在这项研究中，通过将其参数表示为 LET 的函数，对可修复条件可修复 (RCR) 损伤模型进行了扩展，以提供一种能够为给定离子类型和细胞系同时考虑剂量和 LET 的放射生物学模型。将这个 LET 参数化的 RCR 模型拟合到用碳离子辐照 HSG 和 V79 细胞以及用氦离子辐照 T1 细胞的已发表的细胞存活数据。为了测试模型的稳健性，仅对部分数据进行了拟合。模型与细胞存活数据吻合良好，包括未用于模型拟合的 LET 值的存活数据，这为在轻离子治疗计划中使用该模型开辟了可能性。
