CAR-Study A is a prospective study to evaluate cognitive functioning after GKRS in patients with 1-10 newly diagnosed brain metastases on a triple dose gadolinium-enhanced MRI-scan. Neuropsychological assessment will be performed at baseline and at 3, 6, 9, 12, 15, and 21 months after treatment. Follow-up assessments will be combined with 3-monthly MRI-scans.