[Histopathological changes in the brain after radiotherapy of brain metastasis].

This is the histopathological analysis of 18 post-irradiated brains with metastases of breast cancers. There was no evidence of radiation necrosis, except for one with demyelinization and one with degeneration of nerve cells. There was no radiation damage in re-irradiated group. Whole brain irradiation of about 40 Gy may be safe, but that of 60 Gy or more may be not so safe. It may be more useful for preventing of radiation damage to take split-course-method or shrinking-technique at doses of 40 Gy or more. The combination of chemotherapy and radiation therapy seems to aggravate the course of radiation damage.