碳离子放疗与化疗药物联合应用的生物学效应

碳离子放射治疗（carbon ion radiotherapy，CIRT）属于高线性能量传递（higher linear energy transfer，LET）射线。碳离子射线不但具有适合肿瘤放射治疗的物理剂量分布特征（Bragg峰），而且主要通过导致肿瘤细胞DNA的双链断裂杀灭肿瘤细胞，因此较光子射线具更强的生物学效应，对肿瘤细胞具有更强的杀灭作用。化疗药物与光子放射治疗的联合治疗是目前广泛应用于肿瘤治疗的策略。化疗与放疗的同期应用主要基于其增敏作用。然而，化疗药物是否能增敏碳离子放疗的抗肿瘤效应而不仅仅是叠加效应，目前尚未明确。本文将基于对基础生物学研究（包括细胞学实验及动物实验）到临床研究结果的分析，详细阐述肿瘤碳离子放疗与化疗药物联合治疗的生物学效应。

Biological effects of carbon ion radiation combined with chemotherapy

Carbon-ion beam (CIB) is a high-linear energy transfer (LET) radiation. CIB is featured with more superior physical dose distribution (i.e., Bragg Peak) as compared to photon beam. In addition, it induces more double-bond break thus has higher relative biological effectiveness (RBE) as compared to photon beam. The combined use of chemotherapy and conventional photon radiotherapy has been widely used in the treatment of tumors. Chemotherapy is used concurrently with photonradiotherapy due to its radiosensitization. However, the radiosensitization effect of chemotherapy used with carbon-ion radiotherapy is controversial. In this article, we reviewed the previous studies of biological effects of the combination of carbon ion radiotherapy and chemotherapy in basic biological studies (including cytological and animal experiments) and clinical outcomes, and elaborated the biological effects.