'Gamma knife' is a term used to denote which of the methods of treatment?

Gamma Knife radiosurgery allows for the destruction of a brain lesions without cutting the skin. By focusing many small beams of of radiation on abnormal brain tissue the abnormality can be destroyed while preserving the normal surrounding structures. The Gamma Knife uses 201 narrow beam Cobalt 60 sources all aimed at a common focal point. When the intracranial abnormality is placed at this focal point it can be effectively destroyed. Conditions treatable with Gamma Knife Radiosurgery include: metastatic brain tumors, aeriovenous malformations, acoustic neuromas, meningiomas, pituitary adenomas, and tic doulouroux (trigeminal neuralgia). Patients with malignant tumors, including gliomas and astrocytomas, may also be candidates for Gamma Knife treatment.