1.理论基础及适应症作为肿瘤治疗手段之一的术中放疗(IORT),是在手术暴露或肿瘤切除时,用高能电子束施加一次大剂量(10-25GY)的照射,使射线照射在手术特定区域,而肿瘤未受累脏器经牵拉脱离射线.术中放疗适合于手术不能切除肿瘤或虽能切除但有癌残留的病人,也可作为预防肿瘤局部复发的辅助治疗. 1. Theoretical basis and indications As an intra-operative radiotherapy (IORT), one of the tumor treatment methods, a high dose (10-25 GY) irradiation is performed with a high-energy electron beam during surgical exposure or tumor resection. Surgery in a specific area, and the tumor is not affected by the organs pulled off the ray. Intraoperative radiotherapy is suitable for surgery can not remove the tumor or resection but with cancer residual patients, but also as an adjuvant treatment to prevent local recurrence of tumor.