• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4576-4582
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• 2023

The Korea retrospective dosimetry (KREDOS)-electron paramagnetic resonance (EPR) group undertook an intercomparison investigation utilizing hydroxyapatite. This analysis involved four institutions: the Korea Institute of Radiological and Medical Sciences, Dongnam Institute of Radiological and Medical Sciences, Korean Association for Radiation Application, and Radiation Health Institute of Korea Hydro & Nuclear Power. Following the irradiation of the hydroxyapatite sample, the recorded build-up was analyzed. To validate the reliability of the EPR dosimetry findings and enhance its operational performance, a hydroxyapatite dose-response curve was plotted and dosimetry was performed for a blind sample. The proficiency of each laboratory was assessed by employing an interlaboratory comparison methodology. This involved a comparative analysis of the measurement results by calculating the relative bias, z-score, and En value. The results submitted by the participating laboratories demonstrated satisfactory ratings for doses of 1.006, 3.999, and 6.993 Gy. Following the second intercomparison, efforts to optimize their hydroxyapatite-EPR dosimetry systems are underway in the participating laboratories. The current assessment of hydroxyapatite dose yielded the foundational data required to establish the parameters of dental dosimetry. In future, the third intercomparison experiment will be conducted for exploring other materials.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1826-1833
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• 2020

Administration of stable iodine has been considered a best measure to protect the thyroid from internal irradiation by radioiodine intake, and its efficacy on thyroid protection has been quantitatively evaluated in several simulation studies on the basis of simple iodine biokinetic models (i.e., three-compartment model). However, the new iodine biokinetic model adopted by the International Commission on Radiological Protection interprets and expresses the thyroid blocking phenomenon differently. Therefore, in this study, the new model was analyzed in terms of thyroid blocking and implemented to reassess the protective effects and to produce dosimetric data. The biokinetic model calculation was performed using computation modules developed by authors, and the results were compared with those of experimental data and prior simulation studies. The new model predicted protective effects that were generally consistent with those of experimental data, except for those in the range of stable iodine administration -72 h before radioiodine exposure. Additionally, the dosimetric data calculated in this study demonstrates a critical limitation of the three-compartment model in predicting bioassay functions, and indicated that dose assessment 1 d after exposure would result in a similar dose estimate irrespective of the administration time of stable iodine.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.238-247
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• 2023

The present work represents a technical guideline for decommissioning a disused teletherapy machine model Theratron-780 and contains category one ⁶⁰Co radioactive source. The first section predicts the dose rate from the source in case of normal and radiological emergency situations via FLUKA-MC simulation code. Moreover, the dose assessment for the occupational during the whole process is calculated and compared to the measured values. A suggested cordoned area for safety and security in a radiological emergency is simulated. The second section lists the whole process's technical procedures, including (preview, dismantle, securing, transport and storage) of the disused teletherapy machine. Results show that the maximum obtained accumulated dose for occupational were found to be 24.5 ± 4.9 μSv in the dismantle and securing process in addition to 3.5 ± 1.8 μSv during loading on the transport vehicle and unloading at the storage facility. It was found that the measured accumulated dose for workers is in good agreement with the estimated one by uncertainty not exceeding 5% in normal operating conditions.

• 대한방사선기술학회지:방사선기술과학
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• 제43권4호
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• pp.289-295
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• 2020

This study investigated the feasibility of establishing a college of medicine in the western region of Chungnam to fill the gap in the medical doctor in charge of essential medical care in the region. Currently, the level of medical services in Chungnam is low compared to provinces across the country and in particular, 7 cities and towns, which account for 760,000 people, one-third of Chungnam's population, are located in the western regions of Chungnam. Because of this, in the event of an emergency patients, it is necessary to travel to Cheonan, Daejeon, Seoul, etc. where the regional emergency medical center is located for more than 1 hour and 30 minutes. In the case of critically ill and emergency patients transfer, it is a situation that misses the golden time and causes valuable loss of life. In order to improve the medical environment in the western region of Chungnam and improve the lives of residents in vulnerable areas of medical services, it is believed that establishing a college of medicine in the western region of Chungnam is essential.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2379-2386
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• 2020

This paper presents the results of the first intercomparison exercise performed by the Korea retrospective dosimetry (KREDOS) working group using electron paramagnetic resonance (EPR) spectroscopy. The intercomparison employed the alanine dosimeter, which is commonly used as the standard dosimeter in EPR methods. Four laboratories participated in the dose assessment of blind samples, and one laboratory carried out irradiation of blind samples. Two types of alanine dosimeters (Bruker and Magnettech) with different geometries were used. Both dosimeters were blindly irradiated at three dose levels (0.60, 2.70, and 8.00 Gy) and four samples per dose were distributed to the participating laboratories. Assessments of blind doses by the laboratories were performed using their own measurement protocols. One laboratory did not participate in the measurements of Magnettech alanine dosimeter samples. Intercomparison results were analyzed by calculating the relative bias, E_n value, and z-score. The results reported by participating laboratories were overall satisfactory for doses of 2.70 and 8.00 Gy but were considerably overestimated with a relative bias range of 10-95% for 0.60 Gy, which is lower than the minimum detectable dose (MDD) of the alanine dosimeter. After the first intercomparison, participating laboratories are working to improve their alanine-EPR dosimetry systems through continuous meetings and are preparing a second intercomparison exercise for other materials.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
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• pp.51-56
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• 1996

In a NNP (Nuclear Power Plant) severe accident, radionuclides are dispersed into the air. The official regulatory institute, KINS (Korea Institute of Nuclear Safety), has been authorized and developing Computerized technical Advisory system for the Radiological Emergency preparedness (CARE). In this paper, in line with the CARE system, we presented the result of a modularized intermediate-level emergency dose assessment computer code. The RADCON (RADiological CONsequence analysis) version 3.0, which is operable on PC, is developed for simulating emergency situation by considering continuous washout phenomena, and provide a function of effective emergency planning. The source files are coded by using C language in order to increase the compatibility with the other computer system and modularized to adjust the functions and characteristics of each module fer easy understanding and further modification.

• 대한방사선기술학회지:방사선기술과학
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• 제19권2호
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• pp.51-57
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• 1996

Radiography should be used judiciously and should not delay patients resuscitation. In the patient with emergency multiple trauma, three radiography should be obtained-cervical spine, anteroposterior(AP) chest, and AP pelvis. These examinations can be done in the resuscitation area, usually with a portable X-ray unit, but should not interrupt the resuscitation process. A retrospective study was carried on 157 emergency multiple trauma patients who were admitted to Yong Dong Severance Hospital from January, to December in 1995. I analyzed the types of X-ray examinations in emergency multiple trauma patients, and classified the patients by disoriented group of mentality. The results were as follows: 1. The subjects were 7.1%(157patients) of 2,208 trauma patients(7.3%) in total 30,085 emergency patients. 2. Male to female ratio was 2.57 : 1. The age distribution was highest from 31 years to 40 years(28.0% ). 3. The peak time of patient's entrance in emergency center was between 8 : 00 pm and 2 : 00 am(36.9%), and second peak time was between 2 : 00 pm and 8 : 00 pm (29.3%). 4. According to the injury type, traffic accident, motorcycle accident and falling down were 71.3%, 8.3% and 20.4% respectively. 5. According to the exposure rate of Computed Tomography, chest CT, cervical CT pelvis CT and brain CT were 39.5%, 24.2%, 69.4% and 51.6% respectively.

• Journal of Radiation Protection and Research
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• 제26권4호
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• pp.357-365
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• 2001

정당성 및 최적화 개념이 도입된 비용-이득 접근법에 근거하여 우리나라의 방사선비상시 주민보호조치를 위한 개입준위 설정방법을 이론적으로 유도하였다. 부지특성자료인 각종 보호조치에 소요되는 비용과 선량회피로 얻어지는 금전적 값을 이용하여 옥내대피, 소개, 일시이주 및 영구정착에 대한 방사선 개입준위를 계산하였다. 그 결과 IAEA가 권고한 개입준위가 우리나라에서도 적용 가능함을 확인하였다. 아울러 의사결정에 참고할 수 있도록 최적화된 개입준위의 범위를 옥내대피 5 - 10 mSv/2일, 소개 25 -130 mSv/주, 일시이주 15 - 90 mSv/월 및 영구정착 600 - 3,500 mSv/평생 과 같이 제안하였다. 이 결과는 우리나라의 방사선 개입준위 기준에 대한 근거를 마련하고 기준치를 개선할 수 있는 자료로 활용될 수 있을 것으로 기대된다.

• Journal of Radiation Protection and Research
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• 제48권3호
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• pp.162-166
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• 2023

Background: Assessment of the radiation doses to which workers are exposed can differ depending on the placement of dosimeters on the body. In addition, it is affected by whether the placement is under or over a shielding apron. This study aimed to evaluate the actual positioning of personal dosimeters on the body, with or without shielding aprons, among radiation workers in Korea. Materials and Methods: We analyzed the survey data, which included demographic characteristics, such as sex, age, occupation, work history, and placement of the personal dosimeter being worn, from a cohort study of Korean radiation workers. We assessed the use of personal dosimeters among workers, stratified by sex, age, working period, starting year of work, and occupation. Results and Discussion: Overall, high compliance (89.1% to 99.0%) with the wearing of dosimeters on the chest was observed regardless of workers' characteristics, such as age, sex, occupation, and work history. However, the placement of dosimeters, either under or over the shielding aprons, was inconsistent. Overall, 40.1% of workers wore dosimeters under their aprons, while the others wore dosimeters over their aprons. This inconsistency indicates that radiation doses are possibly measured differently under the same exposure conditions solely owing to variations in the placement of worn dosimeters. Conclusion: Although a lack of uniformity in dosimeter placement when wearing a shielding apron may not cause serious harm in radiation dose management for workers, the development of detailed guidelines for dosimeter placement may improve the accuracy of dose assessment.

• Journal of Radiation Protection and Research
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• 제27권2호
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• pp.89-94
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• 2002

IAEA 안전시리즈 109에 제시된 정당화 및 최적화 절차에 따른 비용-이득 접근법을 적용하여 우리나라에 적합한 방사선비상시 식품섭취제한 개입준위 값을 제안하였다. 관심 핵종은 예탁유효선량 기여도를 고려하여 세 그룹으로 구분하였고 대상식품은 가격에 따라 두 그룹으로 분류하였다. 아울러 제안된 개입준위를 실제 상황에 적용함에 있어서 고려해야할 사항에 대해 논의하였다.