Acute Stage

Occurs during the first six months of exposure to radiation. In this period, organs are damaged, but the damage is not noticeable.

2-5 years

Chronic Stage

The second to fifth year after radiation exposure. Residual tissue damage is apparent. There is deterioration of the capillaries (tiny blood vessels). The result is reduced blood flow and oxygen flow and a build-up of cell waste. Organ function is reduced and resistance to infection is lowered.

Subacute Stage

Occurs during the second six months. As treatment continues, permanent tissue damage becomes evident.

5+ years

Late Clinical Stage

Occurs following the fifth year after radiation exposure. Marked by premature aging and new, radiation-induced cancer growth.