A gamma knife is a device used to treat brain tumors with a high dose of radiation therapy in one day. The device was invented at the Karolinska Institute in 1967 by Lars Leksell, a Swedish neurosurgeon.
The gamma knife device contains 201 cobalt-60 sources of approximately 30 curies (1.1 TBq) each, placed in a circular array in a heavily shielded assembly. The device aims gamma radiation through a target point in the patient's brain. The patient wears a specialized helmet that is surgically fixed to their skull so that the brain tumor remains stationary at target point of the gamma rays. An ablative dose of radiation is thereby sent through the tumor in one treatment session, while surrounding brain tissues are relatively spared.
Gamma Knife is a brand name of a Stereotactic Radiosurgery