Stereotactic Radiosurgery Dose Escalation for Brain Metastases

Inclusion Criteria: * Clinically confirmed brain metastases by CT or MRI criteria. If there is evidence of extra-cranial metastatic disease, it is preferable that the lesions be pathologically confirmed (see section 4.2.5 for excluded histologies) and reviewed by a University of Utah or Huntsman Cancer Hospital pathologist if the initial review was done at an outside facility. * Prior brain surgery is allowed, although a lesion situated in the operative bed would not be selected to receive an experimental dose of SRS treatment. SRS should be delivered 4-6 weeks post-surgery if the patient had a craniotomy for resection of a lesion. Enrollment of a patient with the goal of performing SRS outside of the 4-6 post-craniotomy window is at the PI's discretion. * Patients must have 1-5 untreated brain metastases total. * For patients planning to enroll in Cohort 1a (including expansion) or Cohort 1b: Tumor volume ≤ 4.1888 cm3 by CT or MRI measurement at the time of consultation/screening for the metastatic lesion on trial. Patients who have at least one additional lesion that is larger than the lesions eligible for the expansion cohort, but who are unable to find another open cohort, will have the eligible lesion(s) treated in the expansion cohort, and the remaining lesion(s) treated at the standard dose. * For patients enrolling in the expansion Cohort 1a: Up to five brain metastases with tumor volume ≤ 0.5237 cm3 by CT or MRI measurement at the time of consultation/screening w…