• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.155-159
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• 2019

Radiological properties of newly introduced and existing 3-dimensional (3D) printing materials were evaluated by measuring their Hounsfield units (HUs) at varying infill densities. The six materials for 3D printing which consisted of acrylonitrile butadiene styrene (ABS), a unique ABS plastic blend manufactured by Zortrax (ULTRAT), high impact polystyrene (HIPS), polyethylene terephthalate glycol (PETG), polylactic acid (PLA), and a thermoplastic polyester elastomer manufactured by Zortrax (FLEX) were used. We used computed tomography (CT) imaging to determine the HU values of each material, and thus assess its suitability for various applications in radiation oncology. We found that several material and infill density combinations resembled the HU values of fat, soft tissues, and lungs; however, none of the tested materials exhibited HU values similar to that of bone. These results will help researchers and clinicians develop more appropriate instruments for improving the quality of radiation therapy. Using optimized infill densities will help improve the quality of radiation therapy by producing customized instruments for each field of radiation therapy.

• Clinical and Experimental Pediatrics
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• 제58권12호
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• pp.505-508
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• 2015

It is uncommon for pediatric patients with rhabdomyosarcoma to present with clinical and/or laboratory features of disseminated intravascular coagulation (DIC). We report a case of metastatic alveolar rhabdomyosarcoma with severe bleeding because of DIC in a 13-year-old boy. He experienced persistent oozing at the site of a previous operation, gross hematuria, and massive epistaxis. Two weeks after initiating combination chemotherapy consisting of vincristine, doxorubicin, and cyclophosphamide, the patients' laboratory indications of DIC began to resolve. During this period, the patient received massive blood transfusion of a total of 311 units (26 units of red blood cells, 26 units of fresh frozen plasma, 74 units of platelet concentrates, 17 units of single donor platelets, and 168 units of cryoprecipitate), antithrombin-III and a synthetic protease inhibitor. Despite chemotherapy and radiation therapy, he died 1 year later because of disease progression. In children with metastatic rhabdomyosarcoma and massive DIC, prompt chemotherapy and aggressive supportive care is important to decrease malignancy-triggered procoagulant activities.

• 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.

• Journal of Microbiology and Biotechnology
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• 제22권9호
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• pp.1296-1300
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• 2012

The feasibility of using Deinococcus showing strong resistance to both desiccation and ionizing radiation as a dose indicator of gamma radiation exposure was evaluated. Three Deinococcus strains having different levels of radiation resistance, Deinococcus radiodurans (DRD), Deinococcus radiopugnans (DRP), and the DRD pprI mutant (DRM), were selected to develop an appropriate dose indicator for a broad range of exposures. DRD, DRP, and DRM cultures with different numbers of cells [${\sim}10^7$ to $10^3$ colony forming units (CFU)/$100{\mu}l$] were lyophilized and subjected to various doses of gamma radiation to determine a critical dose that inhibited bacterial growth completely. Finally, a combination of DRD at ${\sim}10^7$ and ${\sim}10^6$ CFU, DRP at ${\sim}10^5$ CFU, and DRM at ${\sim}10^4$ CFU successfully indicated exposure to 5, 10, 20, and 30 kGy of gamma radiation, respectively. This study shows the possibility of developing a qualitative indicator of radiation exposure using Deinococcus.

• 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.

• 대한의용생체공학회:의공학회지
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• 제16권2호
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• pp.129-138
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• 1995

최근 방사선 치료에서 가속기를 이용한 고에너지, 고선량율 X-선과 전자선을 암환자 치료에 이용하고 있다. 치료시 방사선 조사선량의 5% 증감은 방사선 치료성적의 성패를 직접적으로 간여하고 있다고 국제 방사선 규정협회는 규정하고 있다. 본 논문에서는 방사선 치료에 영향을 미치는 빔 파라메터의 변동여부를 빠르고 간편하게 검출해 낼 수 있는 장치를 범용 실리콘 다이오드를 이용하여 제작한후 그 특성에 관해 고찰해 보았다. 13개 다이오드를 X-축 및 Y-축에 각각 7개씩 배열한 후 조사영역의 빔의 대칭도, 편평도, 안정성 등을 검출하여 보았고 방사선 손상에 대한 고찰, 일정기간 후의 변화량, 에너지 의존성 및 심부량 백분률등을 기존의 측정방법인 기체전리함을 이용한방법, 필름을 이용한 방법, 반도체 소자를 이용한 방법과의 값과 비교 분석하였다.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.1-4
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• 2012

Purpose : Hand-held dental x-ray system is a self contained x-ray machine designed to perform intraoral radiography with one or two hands. The issue about its usage as general dental radiography is still in dispute. The aim of the present study was to assess the relationship between the amount of battery charge and the tube voltage in different handheld dental x-ray systems. Materials and Methods : Seven hand-held dental x-ray units were used for the study. Tube voltage was measured with Unfors ThinX RAD (Unfors Instruments AB, Billdal, Sweden) for 3 consecutive exposures at the different amount of battery charge of each unit. The average and the deviation percentage of measured kV from indicated kV of each unit were calculated. Results : Tube voltage of only 1 unit was 70 kV (indicated by manufacturer) and those of the others were 60 kV. Tube voltage deviation percentage from the indicated kV at the fully charged battery was from 2.5% to -5.5% and from -0.8% to -10.0% at the lowest charged battery. Conclusion : Tube voltages of all units decreased as the residual amount of the battery charge decreased. It is suggested that the performance test for hand-held x-ray system should be performed for the minimum residual charged battery as well as the full charged one. Persistent battery charging is suggested to maintain the proper tube voltage of the hand-held portable x-ray system.

• 방사선산업학회지
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• 제17권2호
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• pp.143-150
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• 2023

A graded approach applies safety requirements differentially, depending on the risk potential. An advantage of applying a graded approach is that safety assessments can be conducted repeatedly by focusing on areas with relatively higher risk than on those with low risk when decommissioning a nuclear power plant (NPP). The International Atomic Energy Agency (IAEA) recommends applying a graded approach to decommissioning NPPs worldwide. In Korea, the definition of the graded approach requires to be clarified. This study compared the decommissioning method used in Korean NPPs with the IAEA graded approach and examined whether the graded approach can be applied to decommissioning NPPs in Korea. As a result of the comparison, the preliminary decommissioning plan for Shin-Kori Units 5 and 6 showed that the decommissioning method for Korean NPPs is similar to the five-step IAEA graded approach.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.308-317
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• 1998

Ensuring occupational radiation exposure(ORE) as low as is reasonably achievable(ALARA) has been one of very important requirements in a nuclear power plant. It is well known that about 70 percent of occupational dose has incurred from maintenance jobs in the outage period. To reduce occupational dose effectively, the high-dose jobs in the outage period should be identified with their dose reduction potentials and methods. In this study, a PC-based ORE database program, INSTORE, is developed to evaluate ORE doses in individual jobs, and the ORE data of Kori Units 3 and 4 are assembled to the database. Based on customary job classification, radiation work is classified into 26 main jobs which comprise 61 detailed jobs, and occupational doses are assessed according to each detailed job. As a result, high-dose jobs are identified with dose reduction priority in terms of collective ORE dose. It is recommended that adeqaute dose reduction methods for these jobs should be prepared to improve their working conditions and procedures.

• 방사선산업학회지
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• 제18권1호
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• pp.71-78
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• 2024

For most commercial radiation measurement equipment, manufacturers specify an operating temperature in the range of 0 to +40℃. However, in environments that exceed the quality assurance performance of the safeguards equipment, such as the winter environment in North Korea, the performance of the equipment deteriorates or normal use is impossible. In this study, safeguards equipment measurements were performed by creating an extreme temperature environment using a constant temperature and humidity test chamber. The safeguards equipment used in the evaluation was MIRION's Inspector-2000-based equipment, which evaluated the usability in extreme temperature environments using three types of detection units: NaI(Tl), CZT, and HPGe.