Exposure occurs when all or part of the body receives penetrating radiation (e.g., gamma rays or x-rays, or high-energy beta particles) from an external source.
Diagnosis of ARS usually requires specific blood tests and clinical findings.
An individual exposed to radiation 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 is either absorbed without the body becoming radioactive, or it can pass through the body completely.
Therefore, if a person is scanned with radiation detection equipment, it will not register radiation above background level.
Exposure from an external source stops when the person leaves the area of the source, the source is shielded completely, or the process causing exposure ceases.
Exposure can also occur when a radionuclide is ingested, inhaled or absorbed into the blood stream (internal contamination). This kind of exposure stops only when the radionuclide is totally eliminated from the body (with or without treatment).
Types of exposure:
Whole body exposure: entire person receives penetrating radiation, i.e., no portion of the body is shielded
Partial body exposure: shielding of sufficient thickness blocks a
significant portion of the person from receiving penetrating radiation
