gamma radiation [Gk, gamma + L, radiare, to emit rays] , a very-high-frequency form of electromagnetic radiation consisting of photons emitted by radioactive elements in the course of nuclear transition. The wavelength of gamma radiation is characteristic of the radioactive elements involved and ranges from about 4 × 10−10 to 5 × 10−13 m. Gamma radiation can penetrate thousands of meters of air and several centimeters of soft tissue and bone. It is more penetrating than alpha radiation and beta radiation but has less ionizing power and is not deflected in electric or magnetic fields. Like x radiation, gamma radiation can injure and destroy body cells and tissue, especially cell nuclei. However, controlled application of gamma radiation is important in the diagnosis and treatment of various conditions, including skin cancer and malignancies deep within the body. Also called gamma rays. See also x-ray.
