Background Stereotactic Radiosurgery (SRS) is a localised radiotherapy treatment for patients with brain metastases or other benign tumours in the brain, like meningiomas. The Investigators do not currently know if, or how much, SRS affects brain function. Patients with brain tumours do not get tested routinely for their brain function. Understanding short- and long-term side-effects is important for SRS. Brain metastases patients have short life expectancies (6-months to 1-year). However, meningioma patients can live 10 years or more. SRS is used to treat both. The Montreal Cognitive Assessment will be used to test the participants' brain function. Quality-of-life questionnaires QLQ-C30 and BN20 will also be used to assess the participants' physical and mental wellbeing . These are specific for patients with brain cancer. Why is it important This study aims to identify areas in the brain that relate to changes in brain function after SRS. These areas can then have the radiation dose reduced to them in future patients, hoping to minimise side-effects. Research Question Which regions of the brain contribute to a decline in brain function following SRS. Study Design This is a single centre observational study with prospective and retrospective collection of data. This study will look at two groups of patients: Group1: Patients will complete the MoCA and two quality-of-life questionnaires before the treatment and every 3 months for a year. Group2: Patients will complete the MoCA and two quality-of-life questionnaires once. The investigators will use these tests, MRI scans and the SRS treatment plan to identify areas of the brain that are responsible for any problems with the participants' brain function. The participants for Group 1 will be recruited from the SRS Clinics, at City Campus, Nottingham University Hospitals NHS Trust. The participants for Group 2 will be identified through the Mosaiq Oncology Information System. This pilot study is funded by the Midlands Mental Health and Neurosciences Network.