• 대한방사선치료학회지
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• 제10권1호
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• pp.30-44
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• 1998

Accurate delivery of doses using a high dose rate(HDR) brachytherapy, remote afterloading system(RALS) depends on knowing the strength of the radioactive source at the time of treatment, the precision and consistency of the timer, and the ability of the unit to position the source at the proper dwell location along the applicator. Periodic Quality Assurance(QA) on HDR machines is a part of the standard protocol of any user. The safety of the patient & staff, positional accuracy, temporal accuracy, and dose delivery accuracy are periodically(weekly, quarterly, monthly) estimated using HDR source(Ir-192), treatment planning devices, measurement devices, and overall treatment devices with regard to treatment delivery. The overall measurement results are estimated successfully and assessed its clinical significance. As a result, our HDR brachytherapy units has been very accurate until now. The QA program protocol permits routine clinical use and provides a high confidence level in the accurate operation of HDR units. Therefore, regular QA of HDR brachytherapy is essential for successful treatment.

• Macromolecular Research
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• 제14권4호
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• pp.473-477
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• 2006

The above described semi-transparent monochromators have been operational since 1997. Four units are permanently operating at the ESRF beam line ID14. Two units are in continuous operation at ID 10 and one unit is installed at the APS beamline 8-ID in USA. The water cooling of the crystals is currently being revised and above we showed that improvements most likely are possible by using micro fluidics techniques. Further tests will be performed in collaboration with the CEA-France and tested at ESRF. Parallel developments including nanofluids as coolants are under evaluation. Combination of nanofluidics and microfluidics cooling devices are under study. The authors are grateful to C. Gillot and J-A. Gruss for useful discussions and advices, and to S.Mcheik for his work on the thermal model.

• Journal of Radiation Protection and Research
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• 제47권3호
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• pp.111-133
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• 2022

The exciting advancement related to the "modeling of digital human" in terms of a computational phantom for radiation dose calculations has to do with the latest hype related to deep learning. The advent of deep learning or artificial intelligence (AI) technology involving convolutional neural networks has brought an unprecedented level of innovation to the field of organ segmentation. In addition, graphics processing units (GPUs) are utilized as boosters for both real-time Monte Carlo simulations and AI-based image segmentation applications. These advancements provide the feasibility of creating three-dimensional (3D) geometric details of the human anatomy from tomographic imaging and performing Monte Carlo radiation transport simulations using increasingly fast and inexpensive computers. This review first introduces the history of three types of computational human phantoms: stylized medical internal radiation dosimetry (MIRD) phantoms, voxelized tomographic phantoms, and boundary representation (BREP) deformable phantoms. Then, the development of a person-specific phantom is demonstrated by introducing AI-based organ autosegmentation technology. Next, a new development in GPU-based Monte Carlo radiation dose calculations is introduced. Examples of applying computational phantoms and a new Monte Carlo code named ARCHER (Accelerated Radiation-transport Computations in Heterogeneous EnviRonments) to problems in radiation protection, imaging, and radiotherapy are presented from research projects performed by students at the Rensselaer Polytechnic Institute (RPI) and University of Science and Technology of China (USTC). Finally, this review discusses challenges and future research opportunities. We found that, owing to the latest computer hardware and AI technology, computational human body models are moving closer to real human anatomy structures for accurate radiation dose calculations.

• Radiation Oncology Journal
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• 제24권4호
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• pp.211-216
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• 2006

목 적: 최근 국내 방사선 치료의 발전 경향, 시설 장비와 인적 현황 등 인프라와 특징을 조사하고, 국내 방사선종양학분야의 발전 방향을 모색하려 한다. 대상 및 방법: 2006년도 방사선종양학과 전공의 지도 감독에 관한 실태 조사를 위하여 2006년 7월, 전문의, 전공의, 의학 물리사, 간호사, 방사선사 등 인력 및 치료 장비 인프라 조사와 함께 향후 확장 계획에 관한 조사를 실시하였다. 국내 61개 기관의 치료 시설 등급 결정은 IAEA 조사연구에서 사용한 기준에 따라서 분류하였다. 결 과: 2006년 7월 현재 한국에 설치된 방사선종양학과는 61개 병원이며, 132명의 전문의와 50명의 전공의를 포함하여 선량계산사 및 의학물리사 64명, 방사선사 369명 간호사 130명 등 745명의 인력이 2004년도 기준으로 28,789명 신환의 방사선치료 업무를 담당하고 있다. 방사선치료기는 메가볼티지 치료기가 104대 설치되어 있고 선형가속기가 96대, 코발트 원격치료기 2대, 토모치료기 3대, 사이버나이프가 2대, 한 대의 양성자 치료기가 설치되어 있다. 강내치료 장치는 41개 병원에 설치되어 있으며 이 중 35개 병원에서 고선량률 강내치료기, 6개 병원에서 저선량률 강내치료 장치가 설치 운영되고 있다. 국내 61개 병원의 IAEA기준에 따른 분류에서는 level 0이 2곳, level 1이 15곳, level 2가 19곳이고, level 3 즉 강도조절 방사선치료, 정위적 방사선치료, 수술 중 방사선치료가 가능한 시설이 25곳으로 매우 높은 질의 치료를 시행함을 보여준다. 결 론: 최근 치료시설과 방사선치료 관련 인적 인프라는 현저한 증가 추세에 있다. 즉, 선형가속기의 증가와 함께 코발트 치료기는 현격한 감소를 보이며 토모치료기, 사이버나이프 등 첨단 치료 장치가 증가하는 경향이다. 한국의 메가볼티지 치료기의 숫자는 인구 백만 명당 2.1대로서 향후 방사선치료의 필요성과 적응증이 계속 증가되는 추세에 있어서 치료기의 증가가 필요한 실정이다.

• Journal of Radiation Protection and Research
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• 제34권1호
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• pp.31-36
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• 2009

일부지역의 병원에 설치, 운영되고 있는 진단용 X선 발생장치틀 의원, 병원, 종합병원별로 관 전압, 관 전류/량, 조사기간, 조사선량 성능을 평가하여 측정방법과 기술을 배우고 중요성을 알리고자 한다. 진단용 X선발생장치를 그룹별로 10대씩 총 30대에 대하여 관전류/량, 조사시간측정기를 사용하여, 백분율평균오차로 평가하였고 그에 따른 조사선량의 재현성은 변동계수를 계산하여 평가하였다. 진단용 X선 발생장치 30대 중 부적합한 장치는 관전압정확도 시험에서 5대(16.7%), 관전류정확도시험에서 3대(10,0%), 관전류량정확도 시험에서는 4대(13.3%), 조사시간정확도 시험에서는 5대(16.7%), 조사선량의 재현성 시험에서는 7대(23.3%)로 조사되었다. 진단용 X선 발생장치를 관리규정에 의거하여 성능검사 결과에 의해 성능관리의 심각성을 알 수 있었고, 이에 주기적으로 실시하여야 함은 물론 안전하게 관리함으로써 환자 및 방사선관계종사자에 대하여 방사선으로 인한 방사선 피폭경감, 화질영상관리, 재촬영 감소 둥에 의해 환자에게 양질의 의료서비스를 제공하게 될 것이다. 따라서 정기적인 성능검사가 필요하다고 사료된다.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.598-608
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• 2017

A new radiation scale is proposed. With empathy toward the vast majority of people who are not well versed in radiation and related matters, and thus suffering from misunderstanding that breeds unnecessary fear of radiation, the aim of proposing a new radiation scale, radiation index (RAIN), is to put the general public at ease with the concept of radiation. RAIN is defined in dimensionless numbers that relate any specific radiation dose to a properly defined reference level. As RAIN is expressed in plain numbers without an attached scientific unit, the public will feel comfortable with its friendly look, which in turn should help them understand radiation dose levels easily and allay their anxieties about radiation. The expanded awareness and proper understanding of radiation will empower the public to feel that they are not hopeless victims of radiation. The correspondence between RAIN and the specific accumulated dose is established. The equivalence will allow RAIN to serve as a common language of communication for the general public with which they can converse with radiation experts to discuss matters related to radiation safety, radiation diagnosis and therapy, nuclear accidents, and other related matters. Such fruitful dialogues will ultimately enhance public acceptance of radiation and associated technologies.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.164-167
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• 2005

The noise level of refrigerating units is becoming more important to the manufacturer and the user of the product. Invariably, the compressor is a significant contributor to the overall noise level. Especially a major portion of the noise radiated by the vibration of the compressor shell. This paper presents an approach to relate the dynamic characteristics of the compressor shell with the noise radiation properties and the methods of redesigning the compressor shell to reduce the noise radiation. To relate the dynamic characteristics of the compressor shell with the noise radiation properties, the vibration and radiated sound were measured with the running compressor. Based on the results of these tests correlations between the shell vibration characteristics and the noise radiation properties are identified It was found that the vibration on the compressor shell and the noise radiated from the compressor were stronglycorrelatedincertainfrequencybands.

• Journal of Ginseng Research
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• 제35권3호
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• pp.261-271
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• 2011

Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure.

• Nuclear Engineering and Technology
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• 제45권5호
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• pp.695-700
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• 2013

Thirty-eight radiation safety reports for brachytherapy equipment were evaluated to determine the current status of brachytherapy units in Korea and to assess how radiation oncology departments in Korea complete radiation safety reports. The following data was collected: radiation safety report publication year, brachytherapy unit manufacturer, type and activity of the source that was used, affiliation of the drafter, exposure rate constant, the treatment time used to calculate workload and the HVL values used to calculate shielding design goal values. A significant number of the reports (47.4%) included the personal information of the drafter. The treatment time estimates varied widely from 12 to 2,400 min/week. There was acceptable variation in the exposure rate constant values (ranging between 0.469 and 0.592 ($R{\cdot}m^2/Ci{\cdot}hr$), as well as in the HVLs of concrete, steel and lead for Iridium-192 sources that were used to calculate shielding design goal values. There is a need for standard guidelines for completing radiation safety reports that realistically reflect the current clinical situation of radiation oncology departments in Korea. The present study may be useful for formulating these guidelines.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2229-2236
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• 2021

In nuclear-related facilities, such as nuclear power plants, research reactors, accelerators, and nuclear waste storage sites, radiation detection, and mapping are required to prevent radiation overexposure. Sensor network systems consisting of radiation sensor interfaces and wxireless communication units have become promising tools that can be used for data collection of radiation detection that can in turn be used to draw a radiation map. During data collection, malfunctions in some of the sensors can occasionally occur due to radiation effects, physical damage, network defects, sensor loss, or other reasons. This paper proposes a reproduction strategy for radiation maps using a U-net model to compensate for the loss of radiation detection data. To perform machine learning and verification, 1,561 simulations and 417 measured data of a sensor network were performed. The reproduction results show an accuracy of over 90%. The proposed strategy can offer an effective method that can be used to resolve the data loss problem for conventional sensor network systems and will specifically contribute to making initial responses with preserved data and without the high cost of radiation leak accidents at nuclear facilities.