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You are here: Home > Differences between Contamination and/or Exposure

Differences Between Contamination and Exposure

Differences between contamination and exposure
Contamination - Full Body
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Exposure - Whole Body
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  • Radiation exposure occurs when all or part of the body absorbs penetrating ionizing radiation from an external radiation source, as shown in the illustration above.
    • Exposure from an external source stops when a person leaves the area of the source, the source is shielded completely, or the process causing exposure ceases.
  • Radiation exposure also occurs after internal contamination, i.e., when a radionuclide is ingested, inhaled or absorbed into the blood stream.
    • This kind of exposure stops only if the radionuclide is totally eliminated from the body, with or without treatment.
  • An individual exposed only to an external source of radiation, as shown above, is NOT radioactive or contaminated and may be approached without risk, just like after a chest x-ray or CT scan.
  • Radiation from external exposure alone is either absorbed without the body becoming radioactive, or it can pass through the body completely.
    • Therefore, if a person is scanned with a radiation survey monitor after external exposure alone, the device will not register radiation above the background level.
  • Acute Radiation Syndrome (ARS) may result if the dose from whole or partial body exposure is high enough.
  • How to diagnose ARS: estimate whole body dose and clinical severity by using

US Department of Health & Human Services     
U.S. Department of Health & Human Services Office of the Assistant Secretary for Preparedness and Response National Library of Medicine