The severity and course of the acute radiation sickness depends on how much total dose is received, how much of the body is exposed, and the radio-sensitivity of the exposed individual. The symptoms of acute doses usually appear within the first one or two weeks after the radiation is received.

The severity and the time of onset of early symptoms are important indicators in the determination of what the later symptoms of the acute radiation sickness will be, especially if the absorbed dose is not known.

Select this link for a table from the 2018 EPA PAG showing the effects of various external or internal dose absorption.

Common effects of radiation sickness are discussed on the following pages.