Ten patients (5 male, 5 female) with acoustic neurinoma underwent stereotactic radiosurgery with a gamma unit. Their ages ranged from 29 to 68 years (mean, 52 years). The follow-up periods were 20 to 38 months (mean, 26 months). The doses delivered to the tumor were 9.9 to 13.5 Gy at the periphery and 17 to 30 Gy at the center. Neuroimaging studies showed that 6 tumors became smaller, 3 were unchanged, and 1 was larger. Severe complications such as hydrocephalus were not seen. Hearing was presereved with a change in the pure tone audiometric threshold of 10 dB or less in 6 of the 8 patients tested. One patient became deaf 5 months after surgery. His CT scan had shown large cysts in the tumor before surgery. Indications for this type of therapy for such patients must be decided cautiously.
