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National Cancer Institute U.S. National Institutes of
National Cancer Institute Radioactive I-131 from Fallout
Welcome to the Individual Dose and Risk Calculator for Nevada Test Site fallout
(Version 3.0)

This calculator estimates the radiation dose from I-131 absorbed by your thyroid gland from nuclear tests conducted at the Nevada Test Site (NTS). The calculator estimates your risk of thyroid cancer from this exposure. This calculator also provides an estimate of probability of causation/assigned share (PC/AS) for individuals who have been diagnosed with thyroid cancer.

Testing was conducted at the NTS from 1951 through 1992. However, only the above-ground tests conducted from 1951 through 1962, and some of the underground tests conducted from 1961 through 1970, produced appreciable I-131 fallout in the continental United States and are included in this calculator.

This calculator has been updated to Version 3.0 (as of 10/01/07) to reflect the 2005 conclusions of the National Academies of Science's BEIR VII Committee regarding the effect of gender on the relative risk of radiation induced thyroid cancer.

To use this calculator, you will need to supply:
  • your date of birth and gender
  • the states and counties that you lived in between 1951 and 1971
  • the primary type of milk that you drank (cow or goat)
Note: Before you start the calculator, we urge you to read the Summary Information to learn more about the tests, about I-131 exposure, and about thyroid cancer risks.

If you were born after 1971, you were not affected by tests conducted at the Nevada Test Site. Your estimated I-131 dose from these tests is zero. You do not need to use the calculator.

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The Technical Documentation for this calculator is currently offline. If you need access to it, please e-mail