Title 10 Code of Federal Regulation Part 835, Occupational Radiation Protection (10 CFR 835), requires assessment, recording and reporting of radiation doses to individuals who are exposed to sources of radiation or radioactive contamination. This includes assessing external exposure from a variety of radiation types, such as, beta, photon, and neutron radiation. External exposures may be uniform over the whole body or occur in a non-uniform (i.e., limited body location) fashion. Internal doses occur when radioactive material is taken into the body through ingestion, inhalation, absorption or wounds. The requirements include assessing doses to the whole body, skin, lens of the eyes, extremities and various organs and tissues.
In June 2007, 10 CFR 835 was amended to adopt more current dosimetric models (e.g., International Commission on Radiological Protection Publication 60 (ICRP 60)). Adoption of ICRP 60 dosimetric models included the updating of tissue weighting factors used primarily for assessing radiation doses resulting from intakes of radioactive material. A change in ICRP 60 includes the addition of skin as a specified organ assigned a tissue weighting factor. Prior to the 2007 amendment to 10 CFR 835, skin was not listed as an organ specifically assigned a tissue weighting factor. Other changes to 10 CFR 835 included modification to the magnitude and definition of radiation weighting factors (formerly Quality Factors) which primarily affects neutron dose calculations.
Furthermore, the June 2007 amendment to 10 CFR 835 included a change to the naming convention for dose quantities. Sections 702 and 801 of 10 CFR 835 specify the radiological dose quantities which must be reported annually to monitored individuals. Los Alamos National Laboratory, in accordance with its DOE-approved implementation plan for the amended 10 CFR 835, began reporting dose quantities consistent with the prescribed changes beginning with calendar year 2008 dose results.
The table below describes how the various components of measured and assessed dose quantities are compiled into the results shown on the Annual Occupational Radiation Dosimetry Report.