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按患者年龄修订治疗方法和适应症已被确认。放射生物学及肿瘤细胞动力学的研究,不能说明肿瘤患者个体年龄对肿瘤生长及肿瘤细胞放射敏感性的影响。肿瘤周围正常组织对射线的耐量肯定随着年龄的增长而降低,肿瘤的外照射会使肿瘤周围正常组织受到照射。如4～5周内超过40～50Gy,消化道的照射即出现不能耐受的早期症状,有些将会出现小肠放射性坏死的危险。因此,在治疗盆腔、泌尿生殖器、腹内及消化道肿瘤时,放疗的总量受到限制。腹膜后淋巴结转移癌的放疗很少治愈,因顾虑产生放射性脊髓炎的危险,致使照射不能达到预期根治量。由于超量照射的皮肤反应,迫使外照射入射部位增加。受照正常器官的组织和细胞
The revision of treatment methods and indications according to the age of the patient has been confirmed. The study of radiobiology and tumor cell dynamics cannot explain the effect of individual age on tumor growth and radiosensitivity of tumor cells. The tolerance of the normal tissue around the tumor to the radiation will certainly decrease with age, and the external irradiation of the tumor will cause the normal tissue around the tumor to be irradiated. For example, if the dose exceeds 40 to 50 Gy within 4 to 5 weeks, the early symptoms of intolerable gastrointestinal tract irradiation will appear, and some will have the risk of radioactive necrosis of the small intestine. Therefore, the total amount of radiotherapy is limited in the treatment of pelvic, genitourinary, intra-abdominal, and digestive tract tumors. Radiotherapy for metastatic retroperitoneal lymph nodes is rarely cured, and the risk of radiation-induced myelitis due to concerns has led to a failure to achieve the desired amount of radiation. Due to the over-irradiated skin reaction, the externally irradiated incident site is forced to increase. Tissues and cells that are exposed to normal organs