Stereotactic Radiosurgery (SRS) is a standard-of-care treatment for patients with severe tremor. This clinical trial is a questionnaire-based trial that only involves completion of 2 questionnaires at the consultation appointments with neurology and radiation oncology. The questionnaires only take a few minutes and will provide us with valuable information about how severe the patient's tremor is before and after SRS treatment at 3-month intervals for 1 year. Currently we are only performing SRS treatment on one side of the brain (effects one side of the body) so the side with the worst tremor is treated.