Radiation Risk Assessment Tool - Lifetime Cancer Risk from Ionizing Radiation
RadRAT version 4.1.1
Enter the inputs in the form below or upload an input file.

Demographic Information


Smoking History

A history of smoking will affect the risk of lung cancer, but also the risk of cancers other than lung, because smokers have a different life expectancy compared to the average population. Smoking history is only applicable for the "U.S. 2000-2005" population.

(leave blank if never quit)

Exposure Information

An exposure event may result in doses to one or more organs. All doses associated with the same event should be indicated by entering the same number in the "Exposure Event" column and the same year in the "Exposure Year" column. Refer to Guidance for Entering Exposure Information.

Each organ dose may be entered as a value with no related uncertainty by selecting "Fixed Value" from the Distribution Type menu and typing the value into the "Parameter 1" column. The organ dose may also be entered as an uncertain quantity by selecting one of the probability distributions from the Distribution Type menu. The corresponding distribution parameters should be entered into columns 1, 2, and/or 3.

No. Exposure
Organ Exposure
Distribution Type
Parameters 1,2,3 Help
Delete Dose Exposure
Expand Assumptions, Settings and Report Options

These settings allows the user to control two sampling parameters, sample size and the random seed for sampling.


The reported future lifetime risk represents the risk from the "Current Year" to the end of the expected lifetime. By default, the current year is determined automatically, based on computer settings. However, for the purpose of testing alternative scenarios, different years may be selected.

The User Defined Adjustment Factor is a multiplicative bias parameter that can be used to adjust the estimated lifetime risk to account for additional sources of uncertainty or bias not presently included in the methodology for estimation of lifetime risk.

NOTE: The default setting, a fixed value of 1 entered in the Parameter 1 column, allows the calculation of lifetime risk to proceed without any additional adjustments. Changing the default settings should be done when there is sufficient justification for applying a bias correction.