Gamma Knife radiosurgery is a non-invasive technique that uses focused gamma ray beams to destroy brain abnormalities. It involves using a machine called a gamma knife to deliver a high dose of radiation to a small, precise area of the brain with pinpoint accuracy in a single treatment session. The gamma knife was developed in the 1960s and there are now over 200 centers worldwide. It is effective for treating various types of brain tumors and vascular malformations with minimal damage to surrounding healthy tissue.