Radiosurgery is a one-time application of a high dose of radiation to a stereotactically defined target volume. Radiosurgery differs radically from conventional neurosurgery in that it is generally an outpatient treatment with no incision and few acute complications. No acute change occurs in the pathologic process. Radiosurgery usually relies on one high-dose treatment as opposed to the multiple low-dose fractions inherent in conventional treatment. The goal of radiosurgery is to deliver a high dose to the target, and a minimal, and; it is hoped, harmless dose to normal tissue just a few millimeters away (Friedman et al, 1998).