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, and Börje Larsson, a radiobiologist from Uppsala University.

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 the 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.

Uses

Radiosurgery uses high doses of radiation to kill cancer cells and shrink tumors, delivered precisely to avoid damaging healthy brain tissue. Gamma Knife radiosurgery is able to accurately focus many beams of high-intensity gamma radiation to converge on one or more tumors. Each individual beam is relatively low energy, so the radiation has little effect on intervening brain tissue and is concentrated only at the tumor itself.

Effectiveness

Gamma Knife radiosurgery has proven effective for patients with benign or malignant brain tumors, vascular malformations such as an arteriovenous malformation (AVM), pain or other functional problems. For treatment of trigeminal neuralgia the procedure may be used repeatedly on patients.

The risks of Gamma Knife radiosurgery treatment are very low and complications are related to the condition being treated.