Related facotors of cerebral edema for brain neoplasms after X-knife treatment

Objective: To evaluate the causative factors of cerebral edema for brain neoplasms after X-knife treatment. Methods: One hundred and thirty-three evaluable patients with intracranial lesions were treated with a 6-MV X-knife radiosurgery system. The mean dose delivered, mean dose inhomogeneicity, the mean prescription isodose curve, mean conformity index and target volume ratio were as follows: 20Gy, 13Gy, 80%, 2.20, 2.16. Results: Eighty-three patients experienced cerebral edema and fifty-four of them experienced aggravated edema as a result of treatment. The cerebral edema extent was measured after radiosurgery and was not significantly influenced by the pathology of lesions. Pretreatment edema extent and indexes, whole brain irradiation dose, and lesion size were significantly related to the development of post treatment cerebral edema. The isocenter number, dose inhomogeneicity and maximum dose were also found to influence post-radiosurgery cerebral edema extent. Conclusion: The presence of pretreatment edema, high whole brain irradiation dose and large lesion size are predictors of development of cerebral edema after X-knife treatment.