Correcting Neutron Dosimetry Records for Epidemiology. Part I: Determining a Bias Factor
R.I. Scherpelz; J.J. Fix; D.J. Strom; and R.J. Traub (Pacific Northwest National Laboratory)
The use of occupational radiation monitoring records as a basis for developing a quantitative exposure variable for epidemiologic research presents an ongoing challenge. Even with the most modern dosimetry, accurate measurement of the neutron dose received by a worker can be accomplished only when the dosimeter response can be perfectly tailored for the radiation environment producing the exposure. The task of assessing a reliable dose from historical records adds another layer of difficulty, considering the site's usage of a variety of dosimeters, calibration sources and quantities for measuring the dose of record. In this paper a method is described for determining bias factors that correct historical neutron doses to produce more reliable values that can be used in epidemiological studies. These bias factors were derived for five different nuclear facilities, using a variety of dosimeters based on NTA film and thermoluminescent neutron dosimeters; using calibration sources including PoB, PuF4 and 252Cf; and with original records that recorded doses with such unfamiliar units as single collision RBE dose. The bias factors were derived to convert the original records to Hp(10) and absorbed dose to red bone marrow. *Pacific Northwest National Laboratory is operated for the U.S. Department of Energy by Battelle under Contract DE-AC06-76RLO 1830.