진단방사선영역에서 방사선장치의 이용실태 및 환자피폭선량에 관한 조사연구

김유현,최종학,김성수,이창엽,조평곤,이영배,김철민,Kim Youhyun,Choi Jonghak,Kim Sungsoo,Lee Chanhyeup,Cho Pyongkon,Lee Youngbae,Kim Chelmin 한국의학물리학회 2005 의학물리 Vol.16 No.1

IAEA는 영상의 질에 영향을 주지 않는 범위에서 피부흡수선량의 기준선량을 제시하였다. 이러한 개념은 점차적으로 국제적인 기준으로 사용하게 되었다. 이 기준선량은 강제사항이 아니며 권고사항이지만 방사선촬영에서 아주 훌륭한 기준이 된다. 그러나 IAEA에서 제공한 선량기준은 서양 사람을 기준으로 개발된 것이어서 우리나라 사람에게는 맞지 않고, 상대적으로 우리나라의 환자선량은 적으리라 예상된다. 따라서 방사선촬영 시 촬영부위에 따른 환자 피폭선량에 대한 기준을 따로 개발해야 할 필요가 있다. 본 연구팀은 병원협회에 등록되어 있는 종합병원 278개를 대상으로 환자 피폭에 대한 설문조사를 실시하였다. 설문회수율은 57.9%였으며 각 병원에서 답한 촬영조건을 기초로 NDD법을 이용하여 환자 피폭선량을 계산하였고 방사선장치의 이용현황을 분석한 결과는 다음과 같다 1) 방사선장치의 현황은 일반촬영장치가 42.0%, 투시촬영장치가 29.4%, 치과장치가 13.2%, CT 장치가 8.1% 그리고 유방촬영장치가 7.2%로 나타났다. 2) 방사선장치의 정류방식에 따른 분류는 삼상장치가 29.9%, 인버터장치가 29.5%, 단상장치가 25.5%, 콘덴서방식이 9.0% 그리고 무응답이 6.0%였다. 3) 방사선장치의 수광방식에 따른 분류는 F/S 방식이 46.8%, CR 방식이 26.6%, DR 방식이 17.7% 그리고 무응답이 8.9%로 나타났다. 4) 방사선 촬영건수는 흉부가 49.2%, 척추가 16.8% 그리고 복부가 12.7%순으로 나타났다. 5) 환자 피폭선량은 두부 전후방향촬영 2.23 mGy, 복부 전후방향촬영 3.20 mGy 그리고 흉부 후전방향촬영 0.28 mGy로 나타났다. IAEA's guidance levels have been provided for western people to the end. Guidance levels lower than the IAEA'S will be necessary in view of Korean people's proportions. Therefore, we need to develope the standard doses for Korean people. And we conducted a nationwide survey of patient dose from x-ray examinations in Korea. In this study, the 278 institutions were selected from Members Book of Korean Hospital Association. The valid response rate was approximately 57.9%. Doses were calculated from the questionnaires by NDD method. We obtained the results were as follows; 1) General radiographic equipments were distributed for 42.0%, fluoroscopic equipments 29.4%, dental equipments 13.2%, CT units 8.1 % and mamographic units 7.2%. 2) According to classification by rectification, three-phase equipments were 29.9%, inverter-type generators 29.5%, single-phase equipments 25.5%, constant voltage units 9.0% and unknown units 6.0%. 3) According to classification by receptor system, film-screen types were 46.8%, CR types 26.8%, DR types 17.7% and unknown types 8.9%. 4) The number of examinations were chest 49.2%, spine 16.8% and abdomen 12.7%. 5) Patient doses were head AP 3.44 mGy, abdomen AP 4.25 mGy and chest PA 0.39 mGy.

항공탄약 구매 비용 절감 방안에 관한 연구

김유현,엄정호,Kim, Yu-Hyun,Eom, Jung-Ho 대전대학교 군사연구원 2018 군사학연구 Vol.15 No.-

The ROKAF has been training for a number of exercise for victory in the war, but the lack of aviation ammunition has become a big issue every year. However, due to the limitation of defense resources, there are many difficulties in securing and stockpiling ammunition for the war readiness. Therefore, there is a need to find a way to secure aviation ammunition for war readiness in a more economical way, so In this study, we analyze the precedent research case and the case of the reduction of the purchase cost of weapon system of other countries, and then I have suggested a plan that is appropriate for our situation. As a result of examining previous research cases for this study, there were data that KIDA studied in 2012, Precision-guided weapons acquisition cost reduction measures pursued by US Air Force And the use of procurement agencies that are being implemented by NATO member countries. Based on this study, the following four measures were proposed to reduce the purchase cost of aviation ammunition. First, the mutual aid support agreement was developed to sign the ammunition joint operation agreement. Second, join the NATO Support & Procurement Agency (NSPA) Third, it builds a purchasing community centered on the countries operating the same ammunition Fourth, participating in the US Air Force's new purchase plan for ammunition and purchase it jointly. The main contents of these four measures are as follows. 1. the mutual aid support agreement was developed to sign the ammunition joint operation agreement. Korea has signed agreements on mutual logistics support with 14 countries including the United States, Israel, Indonesia, Singapore, Australia, and Taiwan. The main purpose of these agreements is mutual support of munitions and materials, also supporting the training of the peace time and promoting exchange and cooperation. However, it is expected that there will be many difficulties in requesting or supporting mutual support in actual situation because the target or scope of mutual aid of ammunition is not clearly specified. Thus, a separate agreement on the mutual co-operation of more specific and expanded concepts of aviation ammunition is needed based on the current mutual aid support agreements 2. join the NATO Support & Procurement Agency (NSPA) In the case of NATO, there is a system in which member countries purchase munitions at a low cost using munitions purchase agencies. It is the NATO Purchasing Agency (NSPA) whose mission is to receive the purchasing requirements of the Member Nations and to purchase them quickly and efficiently and effectively to the Member Nations. NSPA's business includes the Ammunition Support Partnership (ASP), which provides ammunition purchase and disarming services. Although Korea is not a member of NATO, NSPA is gradually expanding the scope of joint procurement of munitions, and it is expected that Korea will be able to join as a member. 3. it builds a purchasing community centered on the countries operating the same ammunition By benchmarking the NSPA system, this study suggested ways to build a purchasing community with countries such as Southeast Asia, Australia, and the Middle East. First, it is necessary to review prospectively how to purchase ammunition by constructing ammunition purchasing community centered on countries using same kind of ammunition. 4. participating in the US Air Force's new purchase plan for ammunition When developing or purchasing weapons systems, joint participation by several countries can reduce acquisition costs. Therefore, if the US Air Force is planning to acquire aviation ammunition by applying it to the purchase of aviation ammunition, we will be able to significantly reduce the purchase cost by participating in this plan. Finally, there are some limitations to the method presented in this study, but starting from this study, I hope that the research on these methods will be actively pursued in the future.

방사선치료 장치의 Collimator와 Block에 의한 산란선이 조사선량에 비치는 영향

김유현,Kim, You-Hyun 대한방사선과학회 1994 방사선기술과학 Vol.17 No.2

Endothermic Forster Energy Transfer from DPVBi to BCzVBi in High Efficient Blue Organic Light-Emitting Diodes

김유현,이상연,송욱,신성식,류대현,김우영,Kim, You-Hyun,Lee, Sang-Youn,Song, Wook,Shin, Sung-Sik,Ryu, Dae-Hyun,Wood, Richard,Yatulis, Jay,Kim, Woo-Young Korean Chemical Society 2010 대한화학회지 Vol.54 No.3

본 연구에서는 다양한 농도의 BCzVBi를 청색 형광도판트, DPVBi를 청색 호스트 물질로 적용한 청색OLED 소자를 제작하였다. 최적화된 고효율 청색 OLED 소자의 적층 구조는 NPB (500 ${\AA}$)/DPVBi:BCzVBi-6%(150 ${\AA}$)/$Alq_3$(300 ${\AA}$)/Liq(20 ${\AA}$)/Al (1000 ${\AA}$)으로 구성되었다. 청색 OLED의 최대휘도는 구동전압 13.8V에서13200 cd/$m^2$이고 전류밀도 및 최대효율은 각각 1000 cd/$m^2$의 휘도에서 26.4 mA/$cm^2$, 구동전압 3.9 V에서 4.24 cd/A 이었다. 도핑된 청색 OLED 소자의 발광효율은 도핑되지 않은 소자의 2배에 이른 반면 색좌표는 (0.16, 0.19)로 서로 비슷하였다. BCzVBi가 6% 도핑된 청색 OLED 445 nm와 470 nm에 2개의 EL 스펙트럼의 Peak이 존재하는 반면 도핑되지 않은 순수한 DPVBi 청색OLED 소자는 456 nm에서의 유일한 Peak만을 보여주고 있다. 이는 호스트 물질인 DPVBi의 LUMO와 도판트 물질인 BCzVBI의 LUMO 사이에 분자 진동에 의한 페르스터 에너지 전이에 기인한 것이다. In this study, we demonstrated high-efficiency blue organic light-emitting diodes (OLEDs) employing BCzVBi as a blue fluorescent dye doped into blue host material, DPVBi with various concentration. The optimized blue OLED device having high-efficiency was constructed with structure of NPB (500 ${\AA}$) / DPVBi:BCzVBi-6% (150 ${\AA}$)/$Alq_3$(300 ${\AA}$) / Liq (20 ${\AA}$) / Al (1000 ${\AA}$). The maximum luminescence of blue OLED was 13200 cd/$m^2$ at 13.8 V and current density and maximum efficiency were 26.4 mA/$cm^2$ at 1000 cd/$m^2$ and 4.24 cd/A at 3.9 V, respectively. Luminous efficiency shows two times higher than comparing with non-doped BCzVBi blue OLED whereas $CIE_{x,y}$ coordinate was similar with bare DPVBi blue OLED such as (0.16, 0.19). Electroluminescence of BCzVBi-6% doped blue OLED has two major peaks at 445 nm and 470 nm whereas pure DPVBi's blue peak appears at 456 nm and it is happened through endothermic Forster energy transfer by molecule's vibration between LUMO of DPVBi as host material and LUMO of BCzVBi as dopant in device.

팬텀투과계수와 유효조사면 개념을 이용한 종양선량 확인에 관한 연구

김유현,여인환,권수일,Kim, You-Hyun,Yeo, In-Hwan,Kwon, Soo-Il 대한방사선기술학회 2002 방사선기술과학 Vol.25 No.1

The aim of this study Is to develop a simple and fast method which computes in-vivo doses from transmission doses measured doting patient treatment using an ionization chamber. Energy fluence and the dose that reach the chamber positioned behind the patient is modified by three factors: patient attenuation, inverse square attenuation. and scattering. We adopted a straightforward empirical approach using a phantom transmission factor (PTF) which accounts for the contribution from all three factors. It was done as follows. First of all, the phantom transmission factor was measured as a simple ratio of the chamber reading measured with and without a homogeneous phantom in the radiation beam according to various field sizes($r_p$), phantom to chamber distance($d_g$) and phantom thickness($T_p$). Secondly, we used the concept of effective field to the cases with inhomogeneous phantom (patients) and irregular fields. The effective field size is calculated by finding the field size that produces the same value of PTF to that for the irregular field and/or inhomogeneous phantom. The hypothesis is that the presence of inhomogeneity and irregular field can be accommodated to a certain extent by altering the field size. Thirdly, the center dose at the prescription depth can be computed using the new TMR($r_{p,eff}$) and Sp($r_{p,eff}$) from the effective field size. After that, when TMR(d, $r_{p,eff}$) and SP($r_{p,eff}$) are acquired. the tumor dose is as follows. $$D_{center}=D_t/PTF(d_g,\;T_p){\times}(\frac{SCD}{SAD})^2{\times}BSF(r_o){\times}S_p(r_{p,eff}){\times}TMR(d,\;r_{p,eff})$$ To make certain the accuracy of this method, we checked the accuracy for the following four cases; in cases of regular or irregular field size, inhomogeneous material included, any errors made and clinical situation. The errors were within 2.3% for regular field size, 3.0% irregular field size, 2.4% when inhomogeneous material was included in the phantom, 3.8% for 6 MV when the error was made purposely, 4.7% for 10 MV and 1.8% for the measurement of a patient in clinic. It is considered that this methode can make the quality control for dose at the time of radiation therapy because it is non-invasive that makes possible to measure the doses whenever a patient is given a therapy as well as eliminates the problem for entrance or exit dose measurement.

방사선 치료 장치 및 인력에 관한 연구

김유현,Kim, Yu-Hyeon 대한방사선치료학회 1992 大韓放射線治療技術學會誌 Vol.5 No.1

This report presents the date obtained in a 1990 survery al radiation oncology identified by KSTRO. This study was done to find out the status of current use of the radation thrapy equipments, personnels, utilization of equipments and orther problems in the field of radiation oncology department in korea. Our discussion addresses the areas of regional imbalance in the distribution of megavolage units, buying and selecting the units, improving of quality in radiation treatments. There is increasing use of linear accelerators, simulators, treatment planning computers. The use of Cp-60 units has been prohressively decreasing. And slowly improving, numbers of physicians, physicists, and technologists when compared with the 1988. A total of 51 megavoltage units were identified, giving a ratio of 1.88 technologists/ megavoltage units. We treat average 23.0 patients by megavoltage units.

진단방사선검사에서 환자피폭선량에 관한 연구

김유현(You-Hyun Kim),최종학(Jong-Hak Choi),김성수(Sung-Soo Kim),오유환(Yuw-Han Oh),이창엽(Chan-Hyeup Lee),조평곤(Pyong-Kon Cho),강대현(Dae-Hyun Kang),이영배(Young-Bae Lee),김형철(Hyung-Chul Kim),김철민(Chel-Min Kim) 대한방사선과학회(구 대한방사선기술학회) 2005 방사선기술과학 Vol.28 No.3

진단방사선검사 중에 환자가 받는 X-선량은 인위적으로 만들어낸 방사선피폭 중 가장 큰 비중을 차지하고 있다. 국제적으로 방사선피폭에 대한 진단참고준위가 제안되고 있으며 IAEA는 진단방사선검사와 방사성동위원소검사를 위한 유도준위(guidance level)를 정하여 각국의 실정에 맞게 사용하도록 권고하고 있다. 따라서 다수의 나라에서는 자국의 실정에 맞는 진단참고준위를 정하고자 진단방사선검사에서 환자피폭에 관한 상황을 조사 분석하고 있다. 본 연구는 한국의 실정에 맞는 진단방사선검사에서의 진단참고준위를 설정하고자 일반 X-선촬영, 투시촬영, 전산화단층촬영, 유방촬영 시 환자피폭선량값을 측정하여 NDD법에 의해 계산된 선량과 비교 검토하여 진단참고준위를 제시하고자 수행하였다. X-ray examinations represent the largest man-made source of radiation exposure for the population. The need for standardization of radiation exposures has been suggested and the guidance levels for various radiographic and radioisotope examinations has been proposed by the International Atomic Energy Aency(IAEA) as a safety standard. In many countries, the situation of medical radiographic exposures in each country should be researched before the appropriate guidance level is established. In this study, measurements of entrance surface dose, dose-area product(DAP), computed tomograghic dose index(CTDI) and mean glandular dose(MGD) were carried out in patients who underwent routine x-ray examinations, fluoroscopy, computed tomograghy and mamography in Korea. These measured quantities were compared with the results from the calculation method in previous study. And we suggested diagnostic reference levels in medical imaging in Korea.

초등교사의 소명의식과 행복의 관계에서 회복탄력성과 향상초점의 매개효과

김유현(Kim, Yu-Hyun),김지용(Kim, Ji-Yong),김유미(Kim, You-Me) 학습자중심교과교육학회 2019 학습자중심교과교육연구 Vol.19 No.1

Ⅰ. 서 론 Ⅱ. 연구 방법 Ⅲ. 연구 결과 Ⅳ. 논의 및 제언 본 연구의 목적은 초등교사의 소명의식과 행복의 관계에서 회복탄력성과 향상초 점의 매개효과를 검증하는 데 있다. 이를 위하여 서울특별시 소속 초등교사 315명의 자료를 수집하여 분석하였다. 주요 변인들의 기술통계 및 상관관계를 구하고, 측정 모형 및 연구모형을 검증하였다. 분석결과는 다음과 같다. 첫째, 주요 변인들 간에 모두 유의미한 정적 상관을 보였다. 둘째, 초등교사의 소명의식과 행복의 관계에서 향상초점의 부분매개효과가 확인되었다. 셋째, 초등교사의 소명의식과 행복의 관계 에서 향상초점과 회복탄력성의 순차적 부분매개효과가 확인되었다. 즉, 소명의식은 회복탄력성에 직접적인 영향을 미치지 않고, 향상초점 수준을 높임으로써 회복탄력 성에 간접적 영향을 미치고 이를 통해 행복을 높인다. 본 연구결과는 초등교사의 행복 증진을 위해 소명의식과 향상초점 증진이 중요함을 시사한다.

B형 간염 바이러스의 표면항원과 항체의 양성율 조사

김유현 ( Yoo Hyun Kim ),김교순 ( Kyo Soon Kim ),김명신 ( Myoung Shin Kim ),서정미 ( Jung Mi Seo ),양경희 ( Yang Kyoung Hee ),정미라 ( Mi Ra Chung ) 대한임상검사과학회 2001 대한임상검사과학회지(KJCLS) Vol.33 No.2

Worldwide viral hepatitis is still recognized as a major public health problem particularly in developing countries. The most common etiologies are acute viral hepatitis A and B, and approximately half of the world’s population lives in regions of high hepatitis B virus(HBV) endemicity. HBV infection is hyperendemic in Korea. A Total number of 4,751 serum(ma1e 2,945, female 1,806) collected from the outpatients in Dae Han General Hospital had been tested to detect for hepatitis B surface antigen(HBsAg) and anti-HBs by reverse passive hemagglutination (RPHA) and passive hemagglutination (PHA) method during the period August, 2000 to July, 2001. The positive rate for HBsAg was 4.86%(231/4,751), and that of male was 5.20% higher than female 4.32%. The positive rate of HBsAg by age group was the highest positive rate group in 30-39 years(6.34%), and under 9 years(0.97%) was lowest of alL πle positive rate for anti-HBs was 37.82%(1,797/4,751), and positive rate of female was 41.42% higher than male 35.62%. The positive rate of anti-HBs by age group was the highest positive rate group in 10-19 years(4 1.37%), and under 9 years(20.39%) was lowest rate of all.

순환유동층 보일러 튜브 결함 진단을 위한 진단장치 개발

김유현(Yu-Hyun Kim),정인규(In-Kyu Jeong),반재교(Jae-Kyo Ban),김재영(JaeYoung Kim),김종면(Jong-Myon Kim) 한국컴퓨터정보학회 2018 한국컴퓨터정보학회 학술발표논문집 Vol.26 No.2