• 한국방사선학회논문지
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• 제11권5호
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• pp.321-328
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• 2017

D-Shuttle (Chiyoda Technol Corporation, Tokyo, Japan) 선량계를 이용하여 개인피폭관리 및 자연방사선량의 모니터링을 위한 기초자료를 제공하는데 연구의 목적이 있다. D-Shuttle을 이용하여 선량을 산출하였다. 선량보고서에서 400 일 노출되었을 때에 1.346 mSv 이었고, 연간선량 (annual dose per year)은 1.228 mSv/year, 평균시간선량 (average dose per hour)은 $0.014{\mu}Sv/hr$ 이었다. 국내의 개인 외부피폭선량 (1.295 mSv/year =Korea average natural individual external dose), 국내의 연간부가선량 (additional dose per year)은 -0.0663 mSv/year 이다. D-Shuttle은 방사선모니터링을 위한 개인선량계로 방사선의 검출성능 우수한 기능, 실시간 방사선 피폭관리, 방사선 작업의 경보 기능, 효율적이고 사용이 편리한 개인 방사선선량의 피폭관리로 ALARA에 매우 유용한 선량계로 사용할 수 있다. 방사선작업종사자와 지역주민의 방사선모니터링 측정기기로 병원, 산업, 의료현장, 원전사고 지역과 비파괴 분야의 위험한 지역에서 방사선모니터링으로 활용될 수 있다.

• Journal of Radiation Protection and Research
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• 제36권4호
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• pp.183-189
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• 2011

To quantitatively evaluate how setup errors in conjunction with dose gradients contribute to the error in IMRT dose quality assurance (DQA) measurements. The control group consisted of 5 DQA plans of which all individual field dose differences were less than ${\pm}5%$. On the contrary, the examination group was composed of 16 DQA plans where any individual field dose difference was larger than ${\pm}10%$ even though their total dose differences were less than ${\pm}5%$. The difference in 3D dose gradients between the two groups was estimated in a cube of $6{\times}6{\times}6\;mm^3$ centered at the verification point. Under the assumption that setup errors existed during the DQA measurements of the examination group, a three dimensional offset point inside the cube was sought out, where the individual field dose difference was minimized. The average dose gradients of the control group along the x, y, and z axes were 0.21, 0.20, and 0.15 $cGy{\cdot}mm^{-1}$, respectively, while those of the examination group were 0.64, 0.48, and 0.28 $cGy{\cdot}mm^{-1}$, respectively. All 16 plans of the examination group had their own 3D offset points in the cube. The individual field dose differences recalculated at the offset points were mostly diminished and thus the average values of total and individual field dose differences were reduced from 3.1% to 2.2% and 15.4% to 2.2%, respectively. The offset distribution turned out to be random in the 3D coordinate. This study provided the quantitative data that support the large individual field dose difference mainly stems from possible geometric errors (e.g., random setup errors) under the influence of steep dose gradients of IMRT field.

• 방사성폐기물학회지
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• 제19권2호
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• pp.243-253
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• 2021

In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.725-733
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• 2023

The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, H_p(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting H_p(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

• Journal of Radiation Protection and Research
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• 제30권4호
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• pp.175-183
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• 2005

2002년 기준으로 국내 52733명의 방사선 작업종사자에 대해 5개 대분류와 28개의 세분류 카테고리로 나눈 직업군별 연간 피폭선량의 분포를 분석하였다. 진단용 X선 분야(치과용 포함) 종사자의 선량 통계는 식품의약품안전청이 제공하였으며 기타 종사자의 선량자료는 한국방사성동위원소협회가 제공하였다. 직업군에 따른 선량준위별, 연령별 성별 종사자수와 연간 평균선량을 분석한 결과 거의 80% 정도의 종사자들이 연간 1.2mSv 이하로 피폭하는 것으로 나타났다. 방사선작업 종사자의 총 집단선량은 66.4man-Sv로 나타났고 평균 선량은 1.26mSv였다. 직업군별로는 체내 핵의학 분야와 비 파괴검사 분야 종사자가 다른 분야에 비해 평균선량이 현저히 높게 나타났다. 진단용 X선 분야 종사자에게서 연간 20mSv 이상 피폭자 수가 상당하여 이에 대한 추가 분석이 필요한 것으로 나타났다. 16기의 원자력발전소 작업종사자 중에는 20mSv를 초과하는 종사자가 한명도 없는 것으로 나타났다. 연령별로 30대 종사자 수가 가장 많았고 20대 종사자의 선량이 상대적으로 높았다. 여성이 전체 작업종사자의 20%정도를 차지하고 있었으며 평균 피폭선량은 남성의 반 정도인 것으로 나타났다.

• 방사선산업학회지
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• 제9권1호
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• pp.47-55
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• 2015

Research and investigation is required for the exposure dose of radiation workers to work in the dental hospital as increasing interest in exposure dose of the dental hospital recently accordingly, study aim to minimize radiation exposure by making a follow-up study of individual exposure doses of radiation workers, analyzing the status on individual radiation exposure management, prediction the radiation disability risk levels by radiation, and alerting the workers to the danger of radiation exposure. Especially given the changes in the dental hospital radiation safety awareness conducted the study in order to minimize radiation exposure. This study performed analyses by a comparison between general and dental hospital, comparing each occupation, with the 116,220 exposure dose data by quarter and year of 5,811 subjects at general and dental hospital across South Korea from January 1, 2008 through December 31, 2012. The following are the results obtained by analyzing average values year and quarter. In term of hospital, average doses were significantly higer in general hospitals than detal ones. In terms of job, average doses were higher in radiological technologists the other workes. Especially, they showed statistically significant differences between radiological technologists than dentists. The above-mentioned results indicate that radiation workers were exposed to radiation for the past 5 years to the extent not exceeding the dose limit (maximum $50mSv\;y^{-1}$). The limitation of this study is that radiation workers before 2008 were excluded from the study. Objective evaluation standards did not apply to the work circumstance or condition of each hospital. Therefore, it is deemed necessary to work out analysis criteria that will be used as objective evaluation standard. It will be necessary to study radiation exposure in more precise ways on the basis of objective analysis standard in the furture. Should try to minimize the radiation individual dose of radiation workers.

• Journal of Radiation Protection and Research
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• 제42권4호
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• pp.205-211
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• 2017

Background: Radiation is used in a variety of areas, but it also poses potential risks. Although radiation is often used with great effectiveness in many applications, people perceive potential risks associated with radiation and feel anxious about the possibility of radiation exposure. Various methods of measuring radiation doses have been developed, but there is no way for the general public to measure their doses with ease. Currently, many people use smartphones, which provide information about the location of an individual phone through network connections. If a smartphone application could be developed for measuring radiation dosage, it would be a very effective way to measure individuals' radiation doses. Thus, we conducted a survey study to assess the social acceptance of such a technology by the general public and their intent to use that technology to measure radiation doses, as well as to investigate whether such an intention is correlated with anxiety and attitudes toward the use of radiation. Materials and Methods: A nationwide online survey was conducted among 355 Koreans who were 20 years old or older. Results and Discussion: Significant differences were found between the genders in attitudes, perceptions of radiation risk, and fears of exposure to radiation. However, a significant difference according to age was observed only in the intent to use a smartphone dose measurement application. Attitudes towards the use of radiation exerted a negative effect on radiation risk perception and exposure anxiety, whereas attitudes towards the use of radiation, risk perception, and anxiety about exposure were found to have a positive impact on the intent to use a smartphone application for dose measurements. Conclusion: A survey-based study was conducted to investigate how the general public perceives radiation and to examine the acceptability of a smartphone application as a personal dose monitoring device. If such an application is developed, it could be used not only to monitor an individual's dose, but also to contribute to radiation safety information infrastructure by mapping radiation in different areas, which could be utilized as a useful basis for radiation research.

• Journal of Radiation Protection and Research
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• 제42권4호
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• pp.222-228
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• 2017

Background: On June 18, 2017, Korea's first commercial nuclear reactor, the Kori Nuclear Power Plant No. 1, was permanently suspended, and the capacity of nuclear power generation facilities will be adjusted according to the governments denuclearization policy. In these circumstances, it is necessary to assess the quality of radiation safety management in nuclear power plants in Korea by evaluating the radiation dose associated with them. Materials and Methods: The average annual radiation dose per unit, the annual radiation dose per person, and the annual dose distribution were analyzed using the radiation dose database of nuclear reactors for the last 5 years. The results of our analysis were compared to the specifications of the Nuclear Safety Act and Medical Law in Korea. Results and Discussion: The annual average per unit radiation dose of global major nuclear power generation was 720 man-mSv, while that of Korea's nuclear power plants was 374 manmSv. No workers exceeded 50 mSv per year or 100 mSv in 5 years. The individual radiation dose according to occupational exposure was 0.59 mSv for nuclear workers, 1.77 mSv for non-destructive workers, and 0.8 mSv for diagnostic radiologists. Conclusion: The radiation safety management of nuclear power plants in Korea has achieved the best outcomes worldwide, which is considered to be the result of the as-low-as-reasonably-achievable (ALARA) approach and strict radiation safety management. Moreover, the occupational exposures were also very low.

• 한국환경보건학회지
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• 제49권1호
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• pp.1-10
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• 2023

Low-dose radiation exposure has received considerable attention because it reflects the general public's type and level of exposure. Still, controversy remains due to the relatively unclear results and uncertainty in risk estimation compared to high-dose radiation. However, recent epidemiological studies report direct evidence of health effects for various types of low-dose radiation exposure. In particular, international nuclear workers' studies, CT exposure studies, and children's cancer studies on natural radiation showed significantly increased cancer risk among the study populations despite their low-dose radiation exposure. These studies showed similar results even when the cumulative radiation dose was limited to an exposure group of less than 100 mGy, demonstrating that the observed excess risk was not affected by high exposure. A linear dose-response relationship between radiation exposure and cancer incidence has been observed, even at the low-dose interval. These recent epidemiological studies include relatively large populations, and findings are broadly consistent with previous studies on Japanese atomic bomb survivors. However, the health effects of low-dose radiation are assumed to be small compared to the risks that may arise from other lifestyle factors; therefore, the benefits of radiation use should be considered at the individual level through a balanced interpretation. Further low-dose radiation studies are essential to accurately determining the benefits and risks of radiation.

• Journal of Radiation Protection and Research
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• 제45권2호
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• pp.88-94
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• 2020

Background: The International Commission on Radiological Protection (ICRP) has recently published report series on the occupational intakes of radionuclides (OIR) for internal dosimetry of radiation workers. In this study, the optimized monitoring program including the monitoring interval and the minimum detectable activity (MDA) of major radionuclides was suggested to perform the routine individual monitoring of internal exposure based on the ICRP OIR. Materials and Methods: The derived recording levels and the critical monitoring quantities were reviewed from international standards or guidelines by the International Atomic Energy Agency (IAEA), the International Organization for Standardization (ISO), and the European Radiation Dosimetry Group (EURADOS). The OIR data viewer provided by ICRP was used to evaluate the monitoring intervals and the MDA, which are derived from the reference bioassay functions and the dose coefficients. Results and Discussion: The optimal monitoring intervals were determined taking account of two requirement conditions on the potential intake underestimation and the MDA values. The MDA requirement values of the selected radionuclides were calculated based on the committed effective dose from 0.1 mSv to 5 mSv. The optimized routine individual monitoring program was suggested including the optimal monitoring intervals and the MDA requirements. The optimal MDA values were evaluated based on the committed effective dose of 0.1 mSv. However, the MDA can be adjusted considering the practical operation of the routine individual monitoring program in the nuclear facilities. Conclusion: The monitoring intervals and the MDA as crucial factors for the routine monitoring were described to suggest the optimized routine individual monitoring program of the occupational intakes. Further study on the alpha/beta-emitting radionuclides as well as short lived gamma-emitting nuclides will be necessary in the future.