External Exposure
The radiation, but not the radioactive material, reaches the person. The source of radiation (radioactive material) is not on the person and not inside the person, therefore, the person is not contaminated. This person is NOT radioactive. This person does not emit radiation and cannot be a hazard to him/herself or anybody else around, including medical personnel. External exposures are either local (such as the hands) or total body. Receiving a dose (exposure) of radiation energy is somewhat like receiving a dose of solar ultraviolet (UV) energy from the sun. The solar energy results in a sunburn, but the person receiving the sunburn is not contaminated by the sun, does not emit UV energy, and does not cause other persons to receive a sunburn. Receiving a small dose of radiation is a very low risk to victims and responders. Receiving a massive dose of radiation constitutes a significant risk to the victims and responders.
Three group graphics explaining radiation exposure, contamination and internal contamination and exposure.
External Contamination
An externally contaminated person has radiological material physically attached to his or her skin and/or hair. Everyone and everything near the release of radioactive material must be treated as potentially externally contaminated. This includes victims, responders, equipment, papers, and evidence. Externally contaminated victims rarely have enough radioactive material on their bodies to create radiation levels dangerous to responders. An externally contaminated person is receiving an external exposure of radiation as long as the radioactive material remains on the individual.
Internal Contamination and Internal Exposure
Occurs when unprotected people ingest, inhale, or are wounded by radioactive material. Open wounds can be a pathway for internal contamination. Internally contaminated victims present a minimal risk to responders. The internally contaminated victim may also be externally contaminated. The skin, mouth, and nose are the most obvious routes to internal contamination. Internally contaminated persons also receive an internal exposure. In general, internal contamination is more dangerous to the victim than external contamination.