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전민철,김성호,김재석,김정호,한만석 한국자기학회 2024 韓國磁氣學會誌 Vol.34 No.1
Dual energy computed tomography uses the difference between high energy and low energy. It is possible to recognize differences in the degree of attenuation of materials, distinguishing differences in properties for each material, and imaging only the desired material. Recently, with the new photon counting detector computed tomography technology, higher spatial resolution, contrast-to-noise ratio, and higher dose efficiency can be expected, so it is expected that more accurate medical imaging diagnosis can be expected in the future. 듀얼에너지 전산화단층촬영은 고에너지와 저에너지 차이를 이용한다. 물질의 감약 정도 차이를 인식할 수 있어 물질마다 특성차이을 구분하고 원하는 물질만을 영상화가 가능하다. 최근에는 광자계수검출기 전산화단층촬영 신기술로 인해 더 높은 공간분해능, 대조도 노이즈 비와 높은 선량 효율을 기대할 수 있기에 향후에는 보다 정확성 높은 의료영상 진단을 기대할 수 있을 것으로 사료된다.
Research on Reducing Radiation Exposure for Clinical Applications of X-ray Attenuation
전민철,한만석,소운영,이현국,김용균,이승열 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.4
This study was aimed at identifing areas with low radiation exposure where workers could be takenin the examination room in case that they had to hold the patients by estimating the attenuationof primary radiation and measuring the spatial distribution of scattered radiation. The laboratoryequipment included on the X-ray generator, a phantom (human phantom), and a dosimeter. Theexperiment measured the performance of the examination system (dose reproducibility), the doseof primary radiation (X-rays), and the dose of scattered radiation (secondary radiation). Both theprimary and the scattered radiation were attenuated by a factor of tube in vacuum experimentaltests of the inverse square law. In this study, the attenuation was 2 2.246 for primary radiationand 2 2.105 for secondary radiation. Natural attenuation occurred as the X-rays passed throughair, and an attenuation equation was established in this study. The equation for primary radiation(1st dose) was y = A1 exp(−x/t1)+y0. The high-intensity contour of the direction for the cathodewas wider than that of the direction for the anode, showing a wide range on the rear side of thecathode and on the rear side of the anode. We tried to find the positions where the workers’radiation exposure could be reduced. When the medical radiation workers have to hold the patientfor an abdominal examination, they should be placed towards the tube anode and on the left sideof the patient. For a lumbar-spine lateral examination, they should be placed towards the tubeanode and behind the patient, and for a femur AP (anterior-posterior) examination, they shouldbe placed towards the tube anode and on the right side of the patient.
전민철,김주옥,정성수,박희선,이정은,문재영,정채욱,강다현,박동일 대한결핵및호흡기학회 2018 Tuberculosis and Respiratory Diseases Vol.81 No.4
Background: We developed an additional laser guidance system to improve the efficacy and safety of conventional computed tomography (CT)–guided per cutaneous transthoracic needle biopsy (PTNB), and we conducted this study to evaluate the efficacy and safety of our system. Methods: We retrospectively analyzed the medical records of 244 patients who underwent CT-guided PTNB using our additional laser guidance system from July 1, 2015, to January 20, 2016. Results: There were nine false-negative results among the 238 total cases. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of our system for diagnosing malignancy were 94.4% (152/161), 100% (77/77), 100% (152/152), 89.5% (77/86), and 96.2% (229/238), respectively. The results of univariate analysis showed that the risk factors for a false-negative result were male sex (p=0.029), a final diagnosis of malignancy (p=0.033), a lesion in the lower lobe (p=0.035), shorter distance from the skin to the target lesion (p=0.003), and shorter distance from the pleura to the target lesion (p=0.006). The overall complication rate was 30.5% (74/243). Pneumothorax, hemoptysis, and hemothorax occurred in 21.8% (53/243), 9.1% (22/243), and 1.6% (4/243) of cases, respectively. Conclusion: The additional laser guidance system might be a highly economical and efficient method to improve the diagnostic efficacy and safety of conventional CT-guided PTNB even if performed by inexperienced pulmonologists.
Spin-coating을 이용하여 Flexible Film에 제작된 ZnO TCO의 특성 분석
전민철,이규탁,박상욱,이경주,문병무,조원주,고중혁,Jun, Min-Chul,Lee, Ku-Tak,Park, Sang-Uk,Lee, Kyung-Ju,Moon, Byung-Moo,Cho, Won-Ju,Koh, Jung-Hyuk 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.4
This article introduces the characterization of spin coated ZnO transparent conducting oxide on the flexible substrates. As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. So, We will investigate the electrical property and optical transmittance of ZnO transparent conducting oxide through the 4-point probe resistivity meter, and ultraviolet-vis spectrometer Lamda 35, respectively.
전민철,조홍준,선우성,소성연 대한가정의학회 2006 Korean Journal of Family Medicine Vol.27 No.6
연구 배경: 니코틴 대체요법과 부프로피온의 사용은 금연에 도움을 줄 수 있으며 부프로피온은 비니코틴 제제로서 금연에 효과가 있다고 알려진 첫번째 치료법이다. 본 연구는 단기간(7주) 부프로피온 사용의 금연성공률을 알아보고자 하였다. 방법: 2003년 5월부터 2004년 1월까지 서울아산병원 가정의학과 외래를 방문한 흡연자(18세 이상, 하루 10개비 이상) 중 사용에 동의한 50명을 대상으로 부프로피온 서방정(WellbutrinⓇ 150 mg)을 사용 후 2주, 7주 금연성공률을 확인하였다. 치료는 부프로피온 서방정을 7주 사용하였으며 처음 6일 동안 150 mg 하루 1번 사용하고 이후 6주 동안 150 mg 하루 2번을 사용하도록 하였다. 금연일은 7일째로 정하였다. 결과: 부프로피온 서방정을 사용한 50명 중 7주까지 추적된 환자는 28명이었다. 탈락된 22명 중 5명을 제외한 17명에서 전화 면접을 시행하였다. 전화 면접이 불가능한 5명을 제외한 45명을 대상으로 한 7주 금연성공률은 26.7%였다. 7주간 추적관찰이 이루어진 28명에서는 2주 금연성공률은 39.2% (11명), 7주 금연성공률은 35.7% (10명)였다. 금연실패의 주된 이유는 스트레스(5명)와 불안(4명)이었으며, 부작용으로 복용을 중단한 경우가 1예 있었다. 가장 흔한 부작용은 불면, 불안, 관절통, 메스꺼움 등이었다. 7주간 추적이 이루어진 28명을 대상으로 한 분석에서 흡연량, 이전 금연 시도여부, 가족 내 흡연자 여부, 우울증 여부, 니코틴 의존도 등은 금연율과 통계적으로 유의한 관련이 없었다. 결론: 본 연구에서의 7주 성공률은 26.7% (추적된 대상자의 경우에는 35.7%)였으며 심각한 부작용은 없었다. 그리고 금연성공에 영향을 주는 요인은 발견되지 않았다. The Success Rate of Sustained-Release Bupropion for Smoking Cessation with 7 Week Follow-UpMin Cheol Jun, M.D., Sung Yon So, M.D., Hong-Jun Cho, M.D., MPH, Ph.D.†, Woo Sung Sun, M.D., MPH, Ph.D.
Li Dopant가 ZnO 세라믹스의 전기적 특성과 미세 구조에 미치는 영향
전민철,고중혁,Jun, Min-Chul,Koh, Jung-Hyuk 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.4
It is well known that Zinc Oxide (ZnO) is an attractive material for its various applications. ZnO has been mostly used as a transparent conducting oxide in liquid crystal displays, solar cells due to its advantages of low cost, high productivity, and excellent electrical conductivity. Notably, flexible-dye-sensitized solar cells (DSSCs) based on polyethylene terephthalate (PET) substrates require low temperature sintering processing conditions. Therefore, low temperature processing conditions have been strongly required for transparent conducting film applications. In this paper, we prepared low temperature-sintered ZnO ceramics employing Li as a sintering aid.
전민철(Min-chelol Jeon),김재석(Jae-Seok Kim),장재욱(Jae-Uk Jang),송보경(Bo-Kyoung Song),한만석(Man-Seok Han) 한국자기학회 2020 韓國磁氣學會誌 Vol.30 No.6
In computed tomography, X-ray attenuation occurs by various organs that make up the human body. The attenuated data is used to create an image that we can observe with our eyes. In the process, the patient is exposed to radiation that cannot be avoided. Recent research is trying to improve the image quality while reducing the radiation exposure dose to the human body. Therefore, reconstruction algorithms of various methods are newly introduced. In the future, along with the development of a reconstruction algorithm, it is expected that the development of a detector that realizes an image of excellent quality with a small dose is expected.