The first Leksell gamma knife procedure was performed in Prague on 26th October 1992 and during the first year 156 patients were treated at the department of stereotactic and radiation neurosurgery. 42% patients suffered from a vascular lesion, 39% of patients from a benign tumour and 19% patients from a malignant tumour. Radiosurgery using the gamma knife is a non-invasive stereotactic neurosurgical procedure. Radiosurgery, as microsurgery, must be evaluated not only early, but also the late effect after the treatment some years. Evaluation of the results is therefore an ongoing process and results of the first year with the 5-year follow up are presented. At this time radiosurgery has a zero treatment mortality and the present morbidity with regard to the diagnosis 0-10%.

        Key words: gamma knife, radiosurgery, arteriovenous malformations, brain tumours.