Gamma Knife

In medicine, the Leksell Gamma Knife is a neurosurgical device used to treat brain tumors with radiation therapy. The device was invented by Lars Leksell, a Swedish neurosurgeon, in 1967 at the Karolinska Institute in Sweden.

The Leksell 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. A killing dose of radiation is thereby sent through the tumor in one treatment session, while all surrounding brain tissues receive less than a killing dose. Read more at Wikipedia, the free encyclopedia.

How is safety ensured?

Because placement accuracy of the shots is critical to localization of the radiation (to the fraction of a millimeter) anything that would degrade this precision is unacceptable. (Continued)