Contamination results when a radioisotope (as gas, liquid, or solid) is released into the environment and then ingested, inhaled, or deposited on the body surface.
Internal contamination results when radioactive material is taken into the body via inhalation or ingestion or open wounds.
Internal contamination continues until the radioactive material decays, is flushed from the body by natural processes, or is removed by medical countermeasures.
