很多肿瘤的生存率有了明显的改进,但很多类型的肿瘤预后仍然很坏,原因之一是远位转移有很高的百分比,就是原发肿瘤放疗有较好的效果,也不会影响肿瘤的远位播散。大约有40％的患者因为局部肿瘤控制失败而死亡。常规放疗失败是由于肿瘤体积较大或相对抗放射。高能射线可能有较好的提高局部治愈率的前 The survival rate of many tumors has been significantly improved, but the prognosis of many types of cancer is still very bad, one of the reasons is that there is a high percentage of distant metastases, that is, the primary tumor radiotherapy has a good effect, it will not affect the tumor The distant position spreads. About 40% of patients die because of local tumor control failure. The failure of conventional radiotherapy is due to the large size or relative radiation resistance of the tumor. High-energy ray may have better pre-treatment to improve the local cure rate