WORK PROCEDURES AND RADIATION EXPOSURE AMONG RADIOLOGIC TECHNOLOGISTS IN SOUTH KOREA

Data integration of National Dose Registry and survey data using multivariate imputation by chained equations

Introduction

Data integration is the process of merging information from multiple datasets generated from different sources, which can obtain more information in comparison to to one data source. All diagnostic medical radiation workers were enrolled in National Dose Registry (NDR) from 1996 to 2011, linked with mortality and cancer registry data. (https://kdca.go.kr/) Survey was conducted during 2012-2013 using self-reported questionnaire on occupational radiation practices among diagnostic medical radiation workers.

Methods

Data integration of NDR and Survey was performed using the multivariate imputation by chained equations (MICE) algorithm.

Results

The results were compared by sex and type of job because characteristics of target variables for imputation depend on these variables. There was a difference between the observed and pooled mean for the frequency of interventional therapy for nurses due to different type of medical facility distribution between observed and completed data. Concerning the marital status of males and females, and status of pregnancy for females, there was a difference between observed and pooled mean because the distribution of the year of birth was different between the observed and completed data. For lifetime status of smoking, the percentage of smoking experience was higher in the completed data than in the observed data, which could be due to reasons, such as underreporting among females and the distribution difference in the frequency of drinking between the observed and completed data for males.

Conclusion

Data integration can allow us to obtain survey information of NDR units without additional surveys, saving us time and costs for the survey.

Use of Biological Dosimetry for Monitoring Medical Workers Occupationally Exposed to Ionizing Radiation

Medical workers are the largest group exposed to man-made sources of ionizing radiation. The annual doses received by medical workers have decreased over the last several decades, however for some applications, like fluoroscopically guided procedures, the occupational doses still remain relatively high. Studies show that for some procedures the operator and staff still use insufficient protective and dosimetric equipment, which might cause an underestimation of medical exposures. Physical dosimetry methods are a staple for estimating occupational exposures, although due to the inconsistent use of protection measures, an alternative method such as biological dosimetry might complement the physical methods to achieve a more complete picture. Such methods were used to detect exposures to doses as low as 0.1 mSv/year, and could be useful for a more accurate assessment of genotoxic effects of ionizing radiation in medical workers. Biological dosimetry is usually based on the measurement of the effects present in peripheral blood lymphocytes. Although some methods, such as chromosome aberration scoring or micronucleus assay, show promising results, currently there is no one method recognized as most suitable for dosimetric application in the case of chronic, low-dose exposures. In this review we decided to evaluate different methods used for biological dosimetry in assessment of occupational exposures of medical workers.

OCCUPATIONAL EXPOSURE CHARACTERISTICS AND FACTORS ASSOCIATED WITH RADIATION DOSES AMONG KOREAN RADIATION WORKERS

This study identified occupational factors associated with radiation exposure in Korea. Survey data of 16 037 workers from 2016 to 2017, including lifestyle factors and occupational characteristics, were combined with the National Dose Registry. Higher average annual doses were observed in groups exhibiting health risk factors such as body mass index (BMI) and smoking. Average annual doses also differed according to occupational characteristics, including average daily working hours, use of radiation protection gear, calendar year of hiring and employment status. Moreover, the influence of different factors on radiation dose differed with occupations. In industrial radiography and nuclear power plants, average daily working hours were the most important factor determining worker radiation doses. In other occupations, such as education, industry and research, calendar year of hiring and duration of employment were the most important factors. This research indicates the need to consider the specific work procedures of occupations to determine exposure variations between or within facilities.

OCCUPATIONAL RADIATION PROCEDURES AND DOSES AMONG NURSES IN SOUTH KOREA

This study investigated occupational radiation procedures and radiation exposures among nurses in South Korea. A total of 530 nurses were surveyed from 2012 to 2013, and the survey data were linked with the dosimetry data. Multiple regression analysis was used to identify the factors associated with radiation dose. The most frequent procedure performed by the nurses was interventional radiology, followed by fluoroscopy and routine X-ray. The average annual effective dose and the cumulative dose were 0.91 mSv and 4.66 mSv, respectively. Characteristics of nurses exposed to high radiation doses were male, completed graduate school or higher, first worked before 2000 and performing interventional procedures, nuclear medicine test and fluoroscopy. Performing nuclear medicine tests and interventional procedures had a significant positive association with high radiation exposure.

Occupational radiation exposure and morbidity of circulatory disease among diagnostic medical radiation workers in South Korea

Objectives

We investigated the association between low-dose external occupational radiation exposure and circulatory disease morbidity among diagnostic medical radiation workers.

Methods

A cohort of 11 500 diagnostic medical radiation workers was linked with the National Dosimetry Registry data and the National Health Insurance Service data. Relative risks (RRs) were calculated to explore the association between occupational factors and circulatory disease morbidity, and excess relative risks per 100 milligray (ERR/100 mGy) were estimated to quantify the radiation dose-response relationship.

Results

Overall, there were 2270 cases of circulatory diseases during 93 696 person-years of observation (average follow-up=8.1 years). RRs for hypertension were significantly increased for individuals who started working before 2000 compared with those who started in 2005 and later. ERR/100 mGy for all circulatory diseases was 0.14 (95% CI −0.57 to 0.99). Radiation risks of cerebrovascular diseases and ischaemic heart disease were non-significantly increased with estimates of individual cumulative doses to the heart (ERR/100 mGy=3.10 (−0.75 to 11.59) and 1.22 (−0.71 to 4.73), respectively). However, ERR estimates were generally more strongly positive for female versus male workers and for younger workers versus more than 50-year-old workers.

Conclusions

This study provides little evidence in support of a positive association between occupational radiation exposure and the overall risk of circulatory disease over a short follow-up period among medical radiation workers in South Korea. However, significantly increased RR with earlier year first worked, elevated ERR in female workers and young workers should be further followed up.

OVERVIEW OF OCCUPATIONAL RADIATION EXPOSURE IN MEDICAL WORKERS IN SANTA CATARINA, BRAZIL, BETWEEN 2014 AND 2017

This study assessed occupational radiation doses in Santa Catarina, Brazil, from 2014 to 2017. Data were collected from Sistema de Informação Estadual de Radiações Ionizantes (SIERI), a compulsory occupational dose registration system established in Santa Catarina in 2014. Most doses were registered as lower than the dosemeter recording level (RL; 99.12%). Diagnostic radiology workers registered doses higher than the RL (61.13%) more frequently than nuclear medicine workers; however, the former received lower doses. Nuclear medicine workers represented 38.87% of dosemeter values higher than the RL, but their mean doses were higher. The professionals who registered the highest doses across both categories were radiology technologists/technicians and nursing workers. Establishment of a compulsory information system is important for monitoring the safety of workers. This study compiled data from the first few years of the SIERI program. Here, we report the current status of exposure in Santa Catarina.