Reconstruction of Radiation Dose Received by Diagnostic Radiologic Technologists in Korea

Abstract

ObjectivesDiagnostic medical radiation workers in Korea have been officially monitored for their occupational radiation doses since 1996. The purpose of this study was to design models for reconstructing unknown individual radiation doses to which diagnostic radiation technologists were exposed before 1996.MethodsRadiation dose reconstruction models were developed by using cross-sectional survey data and the personal badge doses of 8167 radiologic technologists. The models included calendar year and age as predictors, and the participants were grouped into six categories according to their sex and facility type. The annual doses between 1971 and 1995 for those who were employed before 1996 were estimated using these models.ResultsThe calendar year and age were inversely related to the estimated radiation doses in the models of all six groups. The annual median estimated doses decreased from 9.45 mSv in 1971 to 1.26 mSv in 1995, and the associated dose variation also decreased with time. The estimated median badge doses from 1996 (1.22 mSv) to 2011 (0.30 mSv) were similar to the measured doses (1.68 mSv to 0.21 mSv) for the same years. Similar results were observed for all six groups.ConclusionsThe reconstruction models developed in this study may be useful for estimating historical occupational radiation doses received by medical radiologic technologists in Korea.

Projected lifetime cancer risks from occupational radiation exposure among diagnostic medical radiation workers in South Korea

“…Quarterly doses below 0.01 mSv, which is the lowest detectable level of NDR, were assigned at value of 0.005 mSv – the midpoint between 0.01 mSv and zero at the dose reconstruction. For workers who started working with radiation before 1996 ( n = 13,178; 14.0% of the total enrollees in the NDR), historical badge doses were reconstructed using a model in which annual doses were determined as a log-linear function of time and age [ 18 ]. The age at the time of first exposure was estimated for each sex and occupational group using the findings of our previous survey [ 19 ] to determine the first year of radiologic practice for individual workers.…”

Assessing the health effects associated with occupational radiation exposure in Korean radiation workers: protocol for a prospective cohort study

“… 28 For individuals who were working before 1984, radiation doses were not documented; therefore, we will estimate their historical occupational exposure using a dose reconstruction model that includes predictors such as age, sex and work place. 29 For using individual radiation doses to analyse a dose–response relationship, we will use organ absorbed doses estimated from the effective dose from the external exposure in the National Dose Registry. Absorbed organ dose is estimated based on methods using the International Commission on Radiological Protection (ICRP) 116 organ dose conversion coefficients and irradiation geometry factors, 30 considering information about work practices, such as use of protective devices and badge location, from the nationwide survey as suggested by the Million Worker Study 31 and the USRT study.…”

Occupational radiation exposure and its health effects on interventional medical workers: study protocol for a prospective cohort study

“…The radiation doses were not documented for individuals who were working before 1996; therefore, we will estimate their historical occupational exposed doses, by applying our previous methods, using a dose reconstruction model that includes predictors, such as age, gender and workplace. 33 …”