Alternative definition : NCI-GLOSS: A treatment using gamma rays, a type of high-energy radiation that can
be tightly focused on small tumors or other lesions in the head or neck, so very little
normal tissue receives radiation. The gamma rays are aimed at the tumor from many
different angles at once, and deliver a large dose of radiation exactly to the tumor
in one treatment session. This procedure is a type of stereotactic radiosurgery. Gamma
Knife therapy is not a knife and is not surgery. Gamma Knife is a registered trademark
of Elekta Instruments, Inc.;