• Journal of Radiation Protection and Research
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• 제37권4호
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• pp.231-236
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• 2012

This study derived measures to reduce exposure doses by identifying factors which affect the external radiation dose rate of patients treated with radiopharmaceuticals for PET-CT tests. The external radiation dose rates were measured on three parts of head, thorax and abdomen at a distance of 50cm from the surface of 60 PET-CT patients. It showed there are changes in factors affecting the external radiation dose rate over time after the administration of F-18 FDG. The external radiation dose rate was lower in the patients with more water intake than those with less water intake before the injection of radiopharmaceuticals at all three points: right after the injection of radiopharmaceuticals (average 4.17 mins), after the pre-PEET-CT urination step (average 77.47 mins), and right after the PET-CT test (average 114.15 mins). The study also found there is a need to increase the amount of water intake before the injection of radiopharmaceuticals in order to maintain a low external radiation dose rate in patients. This strategy is only possible under the assumption that the quality of the video has not changed after conducting this study on the relations between the image and quality. This study also found a need to use radiopharmaceuticals with the minimum amount needed for each patient because F-FDG doses affects the external radiation dose rate at the point right after the injection of radiopharmaceuticals. Urination frequency was the most significant factor to affect the external radiation dose rates at the point right after the PET-CT test and the point after the pre-PET-CT urination step. There is a need to realize the strategy to increase the urination frequency of patients to maintain the external radiation dose rate low (average 77.47 mins) before and after the injection of radiopharmaceuticals. In addition, at this point, there is a need to take advantage of personal strategies because the external radiation dose rate is lower if the fasting time is shorter, the contrast medium is used, and the amount of water intake is increased after the administration of radiopharmaceuticals. Finally this study found the need to be able to generalize these findings through an in-depth research on the factors affecting the external radiation dose rate, which includes radiopharmaceutical dose, urination frequency, the amount of water intake, fasting time and the use of contrast medium.

• 대한방사선기술학회지:방사선기술과학
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• 제42권5호
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• pp.379-385
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• 2019

Radiation is used for various purposes such as cancer therapy, research of industrial and drugs. However, in case of radiation accidents such as terrorism, collapsing nuclear plant by natural disasters like Fukushima in 2011, very high radiation does expose to human and could lead to death. For this reason, many people are concerning about radiation exposures. Therefore, assessment and research of retrospective radiation dose to human by various path is an necessary task to be continuously developed. Radiation exposure for workers in radiation fields can be generally measured using a personal exposure dosimeter such as TLD, OSLD. However, general people can't be measured radiation doses when they are exposed to radiation. And even if radiation fields workers, when they do not in possession personal dosimeter, they also can't be measured exposure dose immediately. In this study, we conduct retrospective research on reconstruction of dose after exposure by using smart chip card of personal items through Optically Stimulated Luminescence (OSL). The OSL signal of smart chip card shows linear response from 0.06 Gy to 15 Gy and results of fading rate 45 %, 48% for 24 and 48 hours due to the natural emission of radiation in sample, respectively. The minimum detectable limit (MDD) was 0.38 mGy. This values are expected to use as correction values for reconstruction of exposure dose.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2736-2747
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• 2022

The operations in the design lifecycle of a nuclear power plant targeted to be decommissioned lead to neutron activation. Operations in the decommissioning process include cutting, decontamination, disposal, and processing. Among these, cutting is done close to the target material, and thus workers are exposed to radiation. As there are only a few studies on pressurizers, there arises the need for further research to assess the radiation exposure dose. This study obtained the specifications of the AP1000 pressurizer of Westinghouse and the distribution of radionuclide inventory of a pressurizer in a pressurised water reactor for evaluation based on literature studies. A cutting scenario was created to develop an optimal method so that the cut pieces fill a radioactive solid waste drum with dimensions 0.571 m × 0.834 m. The estimated exposure dose, estimated using the tool VISIPLAN SW, in terms of the decontamination factor (DF) ranged from DF-0 to DF-100, indicating that DF-90 and DF-100 meet the ICRP recommendation on exposure dose 0.0057 mSv/h. At the end of the study, although flame cutting was considered the most efficient method in terms of cutting speed, laser cutting was the most reasonable one in terms of the financial aspects and secondary waste.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 추계학술발표회요약집
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• pp.322-322
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• 1998

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1757-1762
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• 2023

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg^-1, respectively. Radiological hazard parameters, such as radium equivalent (Ra_eq), external and internal hazard indices (H_ex, H_in), and gamma index (I_γ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y^-1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y^-1 is lower than recommended limit of 1 mSv y^-1 for public.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.133-140
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• 2016

Backgrounds: The accident at Fukushima Daiichi Nuclear Power Plant (NPP), March 2011, caused serious radioactive contamination over wide area in east Japan. Therefore, it is important to know the effect of the accident and the status of NPP. Materials and Methods: This paper provides a review on the status of radiation dose and radioactive contamination caused by the accident on the basis of publicized information. Results and Discussion: Monitoring of radiation dose and exposure dose of residents has been conducted extensively by the governments and various organizations. The effective dose of general residents due to the accident proved to be less than a mSv both for external and internal dose. The equivalent committed dose of thyroid was evaluated to be a few mSv in mean value and less than 50 mSv even for children. Monitoring of radioactivity concentration has been carried out on food ingredients, milk and tap water, and actual meal. These studies indicated the percentage of foods above the regulation standard was over 10% in 2011 but decreasing steadily with time. The internal dose due to foods proved to be tens of ${\mu}Sv$ and much less than that due to natural $^{40}K$ even in the Fukushima area and decreasing steadily, although high level concentration is still observed in wild plants, wild mushrooms, animals and some kind of fishes. Conclusion: According to extensive studies, not only the effect of the accident but also the pathway and countermeasures against radioactive contamination have been revealed, and they are applied very effectively for restoration of environment and reconstruction of the area.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.424-435
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• 2016

Background: The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. Materials and Methods: The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. Results and Discussion: A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. Conclusion: The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

• 한국콘텐츠학회논문지
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• 제22권7호
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• pp.663-669
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• 2022

본 연구는 세치제에 함유되어지는 불소의 함유량이 1500ppm이하로 상향됨에 따라 시판되어지는 세치제의 불소 함유량도 향상되었다. 이에 따라 인체에 노출되어지는 불소의 양을 예측하고 이를 소비자에게 제공하여 안전한 세치제의 사용에 대한 대안을 제시하는데 목적이 있다. 본 연구는 2021년 3월부터 2주간 1300명을 대상으로 일반적 특성과 구강건강행위를 설문조사하였다. 조사한 결과를 ConsExpo Web 1.0.2. 노출평가하기 위한 입력변수로 사용하였다. 그 결과 불소가 1500ppm함유된 세치제를 사용할 경우남자는 External dose on day of exposure가 2.3×10-2 mg/kg/day, 여자의 경우 2.9×10-2 mg/kg/day, 2-3세 아동은 7.3×10-2 mg/kg/day로 추정되었다. 본 연구결과 시중에 유통되어지는 세치제의 불소함유량이 증가됨에 따라 소비자들의 안전한 사용을 위한 기준을 제시하는데 기초자료로 사용될 것이라 사료되어진다.

• Journal of Radiation Protection and Research
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• 제47권2호
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• pp.93-98
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• 2022

Background: This study aims to derive the characteristics of each work type for industrial radiography based on empirical evidence through expert advice and a survey of radiation workers of various types of industrial radiography. Materials and Methods: According to a Korean report, work types of industrial radiography are classified into indoor tests, underground pipe tests, tests in a shielded room (radiographic testing [RT] room test), outdoor field tests, and outdoor large structure tests. For each work type, exposure geometry and radiation sources were mainly identified through the expert advice and workers' survey as reliable empirical evidence. Results and Discussion: The expert advice and survey results were consistent as the proportion of the work types were high in the order of RT room test, outdoor large structure test, underground pipe test, outdoor field test, and indoor test. The outdoor large structure test is the highest exposure risk work type in the industrial radiography. In most types of industrial radiography, radiation workers generally used ¹⁹²Ir as the main source. In the results of the survey, the portion of sources was high in the order of ¹⁹²Ir, X-ray generator, ⁶⁰Co, and ⁷⁵Se. As the exposure geometry, the antero-posterior geometry is dominant, and the rotational and isotropic geometry should be also considered with the work type. Conclusion: In this study, through expert advice and a survey, the external exposure characteristics for each work type of industrial radiography workers were derived. This information will be used in the reconstruction of organ dose for health effects assessment of Korean radiation workers.

• Journal of Radiation Protection and Research
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• 제7권1호
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• pp.1-10
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• 1982

표준한국인(標準韓國人)의 체위(體位)와 내(內).외부(外部) 피폭선량(被曝線量)을 추정(推定)하기 위하여 한국인(韓國人)의 신장(身長), 체중(體重), 체표면적(體表面積)을 포함(包含)한 체위(體位)와 음식물섭취량(飮食物攝取量) 방사능물질섭취량(放射能物質攝取量) 그리고 환경방사능(環境放射能)에 의한 피폭선량(被曝線量)을 조사분석(調査分析)하여 다음과 같은 결론(結論)을 얻었다. 1) 표준한국인(標準韓國人)의 년령군(年齡群)은 남녀(男女) 모두 $20{\sim}30$세(歲)이며 남자(男子)에 있어서의 신장(身長)은 167cm, 체중(體重)은 61kg, 체표면적(體表面積)은 $1.67m^2$다. 그리고 여자(女子)에 있어서의 신장(身長)은 155cm, 체중(體重)은 51kg, 체표면적(體表面積)은 $1.51m^2$이다. 2) 한국인(韓國人) 성인(成人)은 1인(人) 1일(日) 812.8g(식물성((植物性) 669.6g, 동물성(動物性) 143.2g)의 음식물(飮食物)을 섭취(攝取)한다. 3) 한국인(韓國人) 성인(成人)은 음식물(飮食物)을 통(通)하여 1인(人) 1일(日) 약(約) 1,200pCi(${\beta}$-선(線))의 방사능물질(放射能物質)을 섭취(攝取)한다. 4) 한국인(韓國人) 성인(成人)은 년간(年間) 127mrem의 외부피폭(外部被曝)과, 8mrem의 내부피폭(內部被曝)으로 약(約) 135mrem의 환경방방선(環境放放線)에 피폭(被曝)되는 것으로 추산(推算)되나 이 선량치(線量値)는 앞으로 더 많은 자료(資料)가 보완(補完)됨에 따라 수정(修正)된다고 본다.