Use of a machine to aim high-energy rays at cancer.

Radiation therapy delivered by a machine that focuses on the cancer site.

Radiation therapy that uses a machine located outside of the body to aim high-energy rays at cancer cells.

Radiation that is directed onto the skin over a cancerous region within the body.

(ray-dee-AY-shun): Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external-beam radiation.

Exposure to ionizing radiation when the radiation source is located outside the body. Not to be confused with Internal Radiation, where the radiation source has been deposited inside the body.