EBRT uses high-energy linear accelerators to deliver a precise prescribed dose of radiation to the designated region, allowing as much normal tissue as possible to be spared. However, radiation therapy does damage some healthy cells. Used since the 1950s, EBRT can reduce deep-seated tumors as well as those closer to the skin's surface. Treatment can take up to 12 minutes, during which time the patient must stay perfectly still to ensure that the radiation remains precisely directed to the prescribed region.

Most patients receive EBRT on an outpatient basis and are able to continue with most normal daily activities afterward. Since external radiation does not cause the patient's body to become radioactive, there is no need to avoid contact with others during or after treatment.