Rhode Island Hospital
Providence, RI 02903
Gamma Knife Model C
The Gamma Knife is a precise and powerful tool for treating certain tumors and vascular malformations in the brain. It is actually not a knife at all, but an instrument that emits 201 finely focused beams of gamma radiation. The beam from each individual cobalt source is delivered through holes (or portals) in a device known as a collimator helmet. All 201 beams cross at a single point, and it is only there that enough radiation is delivered to affect the diseased tissue. It is so finely focused that it spares the nearby tissue, so its extreme accuracy (to a half millimeter) is one of its greatest advantages. Gamma Knife surgery is non-invasive; radiation is delivered through the intact skull.
The Gamma Knife was developed by Professor Lars Leksell of the Karolinska Institute in Stockholm, Sweden, and biophysicist Professor Borje Larsson of the Gustaf Werner Institute at the University of Uppsala in Sweden. As early as 1951, Leksell found that a single dose of radiation could destroy almost any deep-brain structure, without the risk of bleeding or infection. He called this technique stereotactic radiosurgery and defined it as the delivery of a single, high dose of radiation to a small and critically located target in the brain.
With advances in such imaging technologies as computerized tomography (CT scan) and magnetic resonance imaging (MRI), we now have more uses for the Gamma Knife technique than ever before. It has become a standard treatment for common neurologic diseases.
How exactly does it work?