Ishikawa Hitoshi, Tsuji Hiroshi, Tsujii Hirohiko
Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS).
Gan To Kagaku Ryoho. 2006 Apr;33(4):444-9.
The carbon ion (C-ion) beams provide unique advantageous biological and physical properties in radiotherapy (RT) for malignant tumors. C-ion beams have a high relative biological effectiveness (RBE) resulting from the high linear energy transfer (LET). In terms of their physical characteristics, C-ion beams exhibit a spread-out Bragg peak (SOBP) and make for a better dose distribution of the target volume by specified beam modulations. Between June 1994 and August 2005, a total of 2,371 patients with malignant tumors were registered in phase I/II dose-escalation studies and clinical phase II trials using C-ion beams generated at Heavy Ion Medical Accelerator in Chiba (HIMAC). In the initial dose-escalation studies, grade 3 or more late rectal complications had developed in some patients. However, the adverse effects were resolved because of the use of appropriate dose levels and modification of the radiation technique. C-ion beams can carry out hypofractionated radiotherapy with a large fraction dose and reduce the overall treatment times compared with conventional radiotherapy. They can also achieve better local tumor control even for radio-resistant tumors such as malignant melanoma, hepatocellular carcinoma and bone and soft tissue sarcomas with minimal morbidity to the normal surrounding tissues.
碳离子（C离子）束在恶性肿瘤放射治疗（RT）中具有独特的生物学和物理优势。由于高线性能量传递（LET），C离子束具有较高的相对生物学效应（RBE）。就其物理特性而言，C离子束呈现出扩展布拉格峰（SOBP），通过特定的束流调制可使靶区剂量分布更佳。1994年6月至2005年8月期间，共有2371例恶性肿瘤患者登记参加了使用千叶重离子医用加速器（HIMAC）产生的C离子束进行的I/II期剂量递增研究和临床II期试验。在最初的剂量递增研究中，部分患者出现了3级或更严重的晚期直肠并发症。然而，由于采用了适当的剂量水平和改进了放疗技术，不良反应得到了解决。与传统放疗相比，C离子束可以进行大分割剂量的低分割放疗，并缩短总体治疗时间。即使对于恶性黑色素瘤、肝细胞癌以及骨和软组织肉瘤等放射抗拒性肿瘤，C离子束也能在对周围正常组织造成最小损伤的情况下实现更好的局部肿瘤控制。
