The Radiation Dose Guide was distributed by Giannini Controls Corporation in Duarte, California. It was used to calculate the exposure to an individual over a specified period of time, at a specified distance from a specified radionuclide. The calculations could also be performed for a nuclide not included on the slide rule if the specific gamma ray constant were known.
The back side of the slide rule has a table indicating the typical annual exposures to the public from cosmic rays at different altitudes and the gamma rays from naturally occurring radionuclides in different types of soils. The latter information was provided by the Oak Ridge Institute of Nuclear Studies (now ORAU).