Gamma Knife

**Semantic type:** Therapeutic or Preventive Procedure

**Definition:** A treatment using gamma rays that are 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.

**Synonyms:** - Gamma Knife Radiosurgery - Gamma Knife therapy