Characteristics and Trends of Occupational Radiation Doses among Korean Radiation Workers (1984-2020).

This study identified characteristics of occupational radiation doses among Korean radiation workers from 1984-2020 using the National Dose Registry. The overall mean effective dose from 1984-2020 was 1.05 mSv y(-1), with the highest mean effective dose of 2.61 mSv y(-1) for non-destructive testing workers. The mean effective dose gradually decreased from 2.97 mSv in 1984 to 0.34 mSv in 2020. The largest decline ratio between 1984 and 2020 was observed in educational institutions at 97.4% (0.84 mSv in 1984 and 0.02 mSv in 2020), followed by industries at 96.5% (2.55 mSv in 1984 and 0.09 mSv in 2020). Compared to 1984, the individual dose-distribution and collective dose-distribution ratios in 2020 decreased by 82.6-99% and 53.7-94.7%, respectively. This downward trend was consistent in all occupations, while decline characteristics were different depending on occupation types, work experience, and changes in radiation safety regulations. Considering that some changes in radiation doses in the registry could be solely based on changing the recording mode regardless of the actual changes in radiation doses, a careful understanding of radiation doses in the registry is particularly relevant for future epidemiological studies.