The Interactive RadioEpidemiological Program (IREP) was developed as part of the effort to update the 1985 Radioepidemiological Tables report. The 1985 report was mandated by the 1983 "Orphan Drug Act" (PL 97-414) which instructs to "devise and publish radioepidemiological tables that estimate the likelihood that persons who have or have had any of the radiation-related cancers and who have received specific doses prior to the onset of such disease developed cancer as a result of these doses."

The Radiation Risk Assessment Tool (RadRAT) is an online calculator for estimating the lifetime risk of cancer incidence for members of the U.S. population (or countries with similar cancer incidence rates) from exposure to ionizing radiation for doses below 1 Gy.

The calculator works using organ-specific dose estimates according to age at exposure and sex. Lifetime total cancer risk and organ-specific risk estimates are outputted along with a 90% uncertainty range.