Stereotactic radiosurgery is a procedure that involves closedskull destruction of an intracranial target using ionizing radiation focused with the assistance of an infracranial guiding device. A sophisticated computer program is used while the patient’s head is held still in a stereotactic frame. Radiosurgical techniques can use ionizing radiation generated by a linear accelerator or a gamma knife. In the gamma knife procedure, a high does of cobalf radiation is delivered to precisely targeted tumor tissue. The dose of radiation can be delivered over a single 4-to 6-hour treatment time. In some situations, some tumors are treated over several weeks.