Radiobiology, principle and technique of radiosurgery.

Stereotactic radiosurgery involves the use of precisely directed closed skull single-session radiation to create a desired radiobiologic response within the intracranial target with minimal effects to surrounding structures or tissues. It provided a way for physicians to administer high single doses of radiation to intracranial targets in patients with relative safety. Rapid advances in imaging and computer technologies in the last decade have resulted in development of a variety of different radiosurgery techniques and their wider applications. The Gamma Knife-, proton beam- and LINAC-based radiosurgery devices represent the three main radiosurgery systems. Successful clinical experience with radiosurgery for a diversity of applications has led to a re-examination of radiobiological principles. For radiosurgical doses, the response of the tumor or target tissue and the adjacent normal tissue seems determined predominantly by the supporting vasculature.