Internal Exposure

Internal exposure occurs due to radioactive materials being taken in via four routes: ingestion together with food; inhalation; absorption from the skin; and wound contamination.

Radioactive materials incorporated into the body emit radiation within the body. Accumulation in some specific organs may occur depending on the types of radioactive materials.

This is largely due to the physicochemical properties of radioactive materials. For example, strontium, having similar properties to calcium, tends to accumulate in calcium-rich parts such as bones once it enters the body; cesium, because of its properties similar to potassium, tends to distribute throughout the body once it enters the body.

Iodine, being a constituent element of thyroid hormones, tends to accumulate in the thyroid, whether it is radioactive iodine or stable iodine.

• Included in this reference material on March 31, 2013
• Updated on March 31, 2017