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

Occupational dose measurement in interventional cardiology practice

Ensuring the safety of healthcare workers in interventional cardiology necessitates effective monitoring of occupational radiation exposure. This study aims to assess the accuracy of the over-apron single dosimetric approach compared with double dosimetric methods and explore the relationship between under-apron and over-apron doses. This investigation showed that the prescribed annual dose constraint of 20 mSv year-1 was not exceeded by the maximum annual occupational doses determined by dosimetric algorithms, which were 0.13 ± 0.02, 0.15 ± 0.02 and 0.27 ± 0.04 mSv, respectively. The study demonstrated excellent statistically significant correlations among single and double dosimetric algorithms and between direct under-apron and over-apron doses. Consequently, single dosimetric algorithms could effectively estimate doses for double dosimetric algorithms, highlighting the limited added value of under-apron measurements. These findings significantly impact the practice of interventional cardiology in Sri Lanka, playing a crucial role in enhancing radiation protection measures.

Assessment of dosimetric approaches in evaluating radiation exposure for interventional cardiologists in Sri Lanka

Interventional cardiologists face significant radiation exposure during interventional cardiology procedures. Therefore, this study focuses on assessing radiation exposure among interventional cardiologists during their procedures. Specifically, it aims to determine the effectiveness of both single and double dosimeter methods in estimating annual occupational radiation doses. This research holds pioneering significance as it represents the very first study undertaken in Sri Lanka. Thirteen interventional cardiologists performed 486 interventional cardiology procedures over three months in three different healthcare institutes. Active Hp(10) dosimeters were placed to measure radiation exposure. Effective doses were calculated using single and double dosimetric algorithms. Annual occupational doses were assessed on an operator basis. Statistical analyses were conducted to assess algorithmic differences and dose variations using the Kruskal-Wallis test and linear regression. The highest annual occupational dose for each dosimetric algorithm received as 2.00 ± 0.24 mSv, 2.29 ± 0.48 mSv, 3.35 ± 0.71 mSv, and 2.64 ± 0.42 mSv, respectively, and remained below the recommended safety limit of 20 mSv/year. The Kruskal-Wallis test revealed no significant differences in the effective doses among double dosimetric algorithms, as well as between single and double dosimetric algorithms (p > 0.05). Linear regression showed strong correlations among various algorithms, demonstrating consistency. The findings of this study hold significant effects on interventional cardiology practice in Sri Lanka, enhancing radiation safety and monitoring.

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

ABSTRACT

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.

Estimation of the historical radiation dose of Korean radiation workers, 1961-1983

Accurate dosimetry plays a key role in evaluating the radiation-induced health risks of radiation workers. The National Dose Registry in Korea contains the dose records of radiation workers in nuclear-related occupations since 1984. Thus, radiation doses for workers before 1984 are often sparse or missing. This study aimed to estimate the historical radiation dose before 1984 for radiation workers in Korea based on dose reconstruction models. The dose reconstruction models were derived from the nationwide self-administered questionnaire survey and the personal badge doses for workers in the cohort of the Korean Radiation Worker Study. The mean estimated annual doses between 1984 and 2016 from the dose reconstruction model were 4.67-0.6 mSv, which closely matched the reported doses of 4.51-0.43 mSv. The mean estimated annual doses between 1961 and 1983 based on the exposure scenarios developed by factors associated with radiation doses ranged from 11.08 to 4.82 mSv. The mean estimated annual doses of individuals in the cohort from 1961 to 1983 ranged from 11.15 to 4.88 mSv. Although caution needs to be exercised in the interpretation of these estimations due to uncertainty owed to the nature of extrapolation beyond the range of observed data, this study offers a sense of the radiation doses for workers during Korea's early period of radiation-related activities, which can be a useful piece of information for radiation-induced health risk assessments.

The influence of microwave electromagnetic radiation on rat heart morphogenesis during thyroidectomy

It is known that electromagnetic radiation affects the functional systems of living beings, in particular, the endocrine and cardiovascular systems and directly the heart cells and their functioning. In this case, the influence of electromagnetic radiation significantly affects the properties of the cardiovascular system and changes physiological processes in it. Moreover, sensitivity to signals is higher for biosystems with a higher level of organization. The method of simulating hypothyroidism for rats makes it possible to develop an experimental model for analyzing morphogenetic changes in the rat heart. Under conditions of hypothyroidism modeling, destructive changes in muscle fibers are observed in the myocardium after thyroidectomy, but after microwave irradiation with an exposure of 45 minutes, a regenerative-compensatory reconstruction of the structural components of the myocardium of the heart wall occurs. After thyroidectomy and microwave irradiation with an exposure of 120 minutes, an increase in degenerative and destructive processes in the heart myocardium was observed. For the first time, a comparative ultramicroscopic study using electron microscopy was carried out. It showed that after electromagnetic irradiation with an exposure of 45 minutes, the general structure of the mitochondrial apparatus does not change. Irradiation with an exposure of 120 minutes causes the destruction of subsarcolemal and paranuclear organelles, edema and degradation of intermyofibrillar mitochondria. After exposure to electromagnetic radiation with the exposure of 45 minutes in a hypothyroid state, a compensatory restructuring of the energy apparatus of the contractile cardiomyocytes of the left ventricle occurs due to the formation of mitochondria and an increase in their contact interaction. After exposure to radiation for 120 minutes, the development of destructive-degenerative processes in the mitochondrial apparatus of left ventricular cardiomyocytes, deepening of damage to intermitochondrial contacts was observed. The most significant increase in the relative volume of the endothelium in the areas of the rat heart myocardium was observed for the case of microwave irradiation only (without experimental hypothyroidism) with exposure duration of 45 minutes. Immunohistochemical study both for the case of microwave irradiation only and for the case of microwave irradiation under conditions of experimental hypothyroidism allows us to conclude that morphogenetic transformations are highly active in the myocardium of the heart when the duration of exposure is 45 minutes. This study will make it possible to develop recommendations for persons with thyroid diseases on the duration of daily exposure of staying in electromagnetic field emitted by devices with characteristics similar to the case under study.

Exposure to radiofrequency radiation increases the risk of breast cancer: A systematic review and meta-analysis

The present systematic review and meta-analysis investigated the association between exposure to radiofrequency radiation and the risk of breast cancer. The published studies that were available in PubMed, Embase, Cochrane Library, Ovid MEDLINE, CINAHL Plus, Web of Science, Airiti Library, Networked Digital Library of Theses and Dissertations and ProQuest until May 2020 were investigated. A total of eight studies (four case-control and four cohort studies) were eligible for quantitative analysis. A significant association between radiofrequency radiation exposure and breast cancer risk was detected [pooled relative risk (RR)=1.189; 95% confidence interval (CI), 1.056-1.339]. Subgroup analyses indicated that radiofrequency radiation exposure significantly increased the risk of breast cancer susceptibility among subjects aged ≥50 years (RR=2.179; 95% CI, 1.260-3.770). Pooled estimates revealed that the use of electrical appliances, which emit radiofrequency radiation, such as mobile phones and computers, significantly increased breast cancer development (RR=2.057; 95% CI, 1.272-3.327), while occupational radiofrequency exposure and transmitters did not increase breast cancer development (RR=1.274; 95% CI, 0.956-1.697; RR=1.133; 95% CI, 0.987-1.300, respectively). It was concluded that radiofrequency radiation exposure significantly increased the risk of breast cancer, especially in women aged ≥50 years and in individuals who used electric appliances, such as mobile phones and computers. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-analysis, an evaluation protocol was prepared and registered with the PROSPERO database (registration no. CRD42018087283).