External irradiation occurs when all or part of the body is exposed to penetrating radiation from an external source. During exposure, this radiation can be absorbed by the body or it can pass completely through. A similar thing occurs during an ordinary chest x-ray. Following external exposure, an individual is not radioactive and can be treated like any other patient. Gamma or photon radiation exposure from a terrorist nuclear event or radiation dispersal device would make the victim at risk for acute radiation syndrome, depending on the dose received. (animations of exposure)