고정식 초점형 격자가 적용된 비정절 실리콘 평판형 검출기에서 초점-격자와 두부 팬텀의 중심 변위에 의한 화질 특성에 관한 연구

최준구,김병기,차선화,김경수,Choi, Jun-Gu,Kim, Byeong-Gi,Cha, Seon-Hwa,Kim, Gyeong-Su 대한디지털의료영상학회 2007 대한디지털의료영상학회논문지 Vol.9 No.1

고정식 초점형 격자가 적용된 비정질 실리콘 평판형 검출기에서 초점-격자간 중심변위와 두부 팬텀의 검출기내 위치 변위가 영상 특성에 미치는 영향을 조사하여, 디지털 의료영상 장비의 올바른 사용 방법을 제안하고자 한다. 고정식 초점형 격자를 적용한 비정질 실리콘 평판형 검출기에서 두부 팬텀을 사용하여 초점-격자간 중심 변위와 두부 팬텀의 위치 변위에 따라 영상을 획득 하였다. 획득된 영상을 NIH(Image J) 영상 분석 프로그램을 이용하여 동일 영역에서의 픽셀값(Pixel value), 히스토그램(Histogram), 도면형상(plot profile), 표면도(Surface plot)등을 분석하고, 표준 촬영 영상과 비교 하였다. 초점-격자간 측 방향 중심 변위와 초점-격자와 두부 팬텀의 이중 변위는 수평, 대각선으로 증가할수록 픽셀의 평균값과 표준편차값이 비례적으로 감소하였다. 또한 높은 픽셀값의 빈도수가 상당히 감소하여 영상의 대조도를 저하시켰고, 변위가 증가할수록 영상 왜곡현상도 증가하였다. 다음으로 두부 팬텀 위치 변위의 픽셀 평균값은 큰 변화가 없었으나 수평, 대각선으로 증가할수록 높은 픽셀값의 빈도수가 감소하는 양상을 보여 영상의 대조도가 저하 되었다. 디지털 검출기의 넓은 관용도와 후처리 능력은 영상의 화소 잡음이 증가하여도 방사선사들이 인지하지 못할 수 있다. 따라서 방사선사는 격자가 장착된 디지털 검출기에서 화소 잡음을 증가시키는 촬영 요인들을 정확히 인지하여 검사에 임해야 할 것이다. This study aim to investigate image characteristics due to focus-grid and head phantom decentering from the armorphos silicon thin film transistor detector the fixed focus-grid is applied, wish to propose right use method of digital medical equipment. Acquired image according to focus-grid and head phantom position decentering using head phantom on armorphos silicon thin film transistor detector the fixed focus-grid is applied. acquired image evaluate pixel value, histogram, plot profile, surface plot using NIB (Image J) image analysis program and compared decentering image with standard image. Mean value and standard deviation value of focus-grid lateral decentering and duplex decentering of focus-grid and head phantom decreased by ratio, consequently increase of horizontality, diagonal decentering. also, deteriorated contrast of image because frequency of high pixel value decreases fairly. according increases decentering, image distortion phenomenon was increase, by next time, pixel mean value of head phantom decentering was no big change but horizontality, diagonal, mean value and standard deviation value of pixel decreased by ratio. Even if increase pixel noise of image because wide latitude and post processing ability of digital detector, radiotechnologist can not recognize. Therefore, radiotechnologist must recognize correctly the photographing factors which increases pixel noise on the grid system installation digital detector and should exam.

닭의 혈액내 단핵세포 표면항원 특이 단클론성 항체 생산

최준구,성환우,김선중,Choi, Jun-Gu,Sung, Haan-Woo,Kim, Sun-Joong 대한수의학회 2002 大韓獸醫學會誌 Vol.42 No.2

This study was performed to produce monoclonal antibodies (mAb) specifically reacting with chicken leukocyte surface antigens. Popliteal lymph node cells of BALB/c mice previously immunized through foot-pad with peripheral blood mononuclear cells (PBMC) of chickens separated by Ficoll-Histopaque method. They were fused with P3X63Ag14 mouse myeloma cells. A total of 34 hybridomas secreted antibodies specifically binding to the PBMC. According to the reactivity patterns with PBMC, the mAbs were divided into 4 groups. Group 1 mAbs (IIB3, IIB10, IIE10) specifically reacted with non-adherent lymphocytes but not with adherent cells which were mainly composed of thrombocytes and monocytes in PBMC culture. These mAbs were reactive with 25-59% of thymus cells and 42-64% of spleen cells of chickens. They did not show any significant reactivity with cells in the bursa of Fabricius, T-cell (MDCC-MSB1) and B-cell (LSCC-1104B1) lines. These results indicate that Group I mAbs specifically reacted with T-lymphocyte subpopulation. Monoclonal antibodies in Group II (IC6, IG2-2 and IID9) showed specific reactivity with monocytes but not with thrombocytes or non-adherent cells in PBMC culture. These mAbs, though not reacted with the chicken macrophage cell line, HD11, also bound to macrophages of the spleen and lung in immunohistochemical staining. Five mAbs in Group III showed characteristics of binding to lymphocytes and monocytes, but not to thrombocytes. Twenty-three mAbs in Group IV showed specific reactivity to lymphocytes, monocytes, and thrombocytes. Two mAbs (IC3 and IE9) in Group IV reacted with most of PBMC.

진단용방사선발생장치의 안전관리에 관한 규칙 개정에 따른 이동형 방사선검사의 개선방안

최준구(Jun-Gu Choi),김경수(Gyeong-Su Kim),김병기(Byeong-Gi Kim),안남준(Nam-Jun Ahn),김형선(Hyeong-Sun Kim),김상건(Sang-Geon Kim),임시은(Si-Eun Lim) 대한방사선과학회(구 대한방사선기술학회) 2007 방사선기술과학 Vol.30 No.1

방사선종사자와 환자 및 보호자의 안전을 위해 개정된 진단용방사선발생장치의 안전관리 규칙이 2006년 2월 10일 공포되었다. 이 규칙에는 중환자실, 수술실, 응급실을 제외한 곳의 방사선검사 시 반드시 방사선방어 용칸막이를 설치하도록 하고 있다. 이 연구의 목적은 이동형 진단용방사선발생장치를 안전하게 관리하여, 방사선으로 인한 위해를 방지하고, 환자 및 보호자들로부터 발생될 수 있는 고객 불만사항들을 최소화 하는데 있다. 조사대상은 병실 이동형 방사선검사환경과 본원의 의료정보시스템(KIS) 및 의료영상전송시스템(PACS)의 통계 데이터를 조사하였다. 그리고 병실 이동형 방사선검사 시 환자 상태 및 감염 등 관련 정보를 조사하여 자료화 하였다. 자료 분석을 통한 이동형 방사선검사에 대한 개정된 규칙을 적용할 경우 고려되는 문제점은 공간적인 측면에서의 제약, 운영적인 측면에서의 인력 및 비용, 업무적인 측면에서 환자 및 보호자 만족도저하 등의 문제가 예상되었다. 따라서 위와 같은 문제를 해결하기 위해 다인병실의 검사를 제한하고, 각 병동에 있는 치료실을 이용하여 검사하도록 하였다. 그 결과 전체 병실 이동형 방사선검사율이 50% 가까이 감소하였고, 거동이 양호한 환자의 병실 이동형 방사선검사율도 85% 이상 감소하였다. 이 결과는 새로운 법 규정에 따라 예상되는 인력, 비용, 고객만족도 저하의 문제들을 해결할 수 있는 대안이 될 수 있었다. 또한 병실 이동형 방사선검사로 인한 환자 및 보호자를 방사선노출로부터 보호하고, 검사로 인한 주위 환자 및 보호자의 불편을 최소화하는데 의의가 있다. A safety management rule of the diagnosis radiation system which opened a court 2006 February 10th was promulgated for safety of the radiation worker, patients and patients" family members. The purpose of this study is to minimize injury by radiation that can happen to patients and people around a sick ward when managing mobile X-ray system. This study analyzed sickroom environment of mobile X-ray examination and the statistical data of the Konkuk medical Information System(KIS) and the Picture Archiving Communication System(PACS). This study also investigated patient conditions, infection, relation information and related data, when the sickroom mobile X-ray examination is used. Through data analysis, many problems were expected such as restriction of space side, manpower and expense of business side, satisfaction degree decline of patient and protector of operation side. Therefore, we tried to restrict examination of multi bed sickroom, and to use treatment room in each ward to solve problem mentioned. As a result, the whole sickroom mobile X-ray examination rate decreased to near 50%, and mobile X-ray examination rate for inpatients decreased to more than 85%. This study shows that several attempts we did should be helpful for manpower, patients satisfaction and expenses. Also, they should protect patients in sickroom from unnecessary radiation exposure and could minimize inconvenience of patients and their family members from x-ray examination.

제약조건 프로그래밍을 이용한 컴퓨터 시스템 성능향상에 대한 연구

최준구(Choi Jun Gu),박기현(Park KeeHyun) 한국정보과학회 1996 한국정보과학회 학술발표논문집 Vol.23 No.1A

본 연구는 시스템의 성능향상을 위하여 투자를 한 경우, 효과적인 성능향상을 꾀하기 위하여, 시스템의 각 구성요소에 할당될 예산의 분배전략을 제시하고, 이를 비교 분석하기 위하여 제약조건 프로그래밍 언어인 CLP(R)을 이용하여 간단한 성능예측 도구를 개발 하였다. 제안된 분배전략은 각 서버의 평균 대기자 수(Queue length)에 비례하여 분배하는 것으로 최적에 근사한 분배비를 얻을 수 있었다.

Current status of vaccine development for African swine fever

최준구(Jun-Gu Choi) 한국예방수의학회 2023 한국예방수의학회 학술대회자료집 Vol.2023 No.-

Pessimistic 실행환경에서 병렬특성을 이용한 근사적 프로세서 할당

최준구(Jun Gu Choi),박기현(Kee Hyun Park) 한국정보과학회 1992 한국정보과학회 학술발표논문집 Vol.19 No.1

최근 다중처리기 운영체제에 대한 연구가 활발히 진행되고 있다. 다중처리기 운영체제의 연구에 있어서, 각 응용 프로그램에 할당할 처리기의 갯수를 결정하는 것은 매우 중요한 문제중의 하나이다. 본 논문에서는 다중프로그래밍이 가능한 다중처리기 시스템의 pessimistic 실행 환경에서 각 응용 프로그램의 병렬특성을 이용하여 근사적인 처리기 할당 알고리즘을 제안하고, 이를 시뮬레이션을 통하여 비교 분석하였다. 처리기 할당방법은 기본적으로 입력되는 각 응용 프로그램의 병렬특성인 평균병렬도와 최대병렬도의 차를 이용하여 할당하였는데, 시뮬레이션 결과 최적 할당과의 상대오차가 MPL이 5인 경우 4.93%~5.44%로 타나났으며, MPL이 7인경우에는 2.54%~12.2%로 나타났다.

Digital Radiography 환경에서 Positioning Block Artifact에 관한 연구

김병기,최준구,이준,이민우,김순배,김경수,Kim, Byung-Ki,Choi, Jun-Gu,Lee, Jun,Lee, Min-Woo,Kim, Sun-Bae,Kim, Gyeong-Su 대한디지털의료영상학회 2008 대한디지털의료영상학회논문지 Vol.10 No.1

Purpose : In sponge quality of the material in digital radiography environment coating because do position blocks two that do not become coating done positioning blocks two that do not become coating done positioning block and sponge quality of the material to testing bench image artifact's difference compare. Method of study : In digital radiography environment positioning block of different two products same sunshine or effect that image and positioning block artifact gents in image analyze. the target used positioning block 2 when examine hand, rib and examination condition did each differently according to used positioning block. reflex compared picture that do image and verify that examine first time. Result : 1. In sponge quality of the material coating in done product artifact appear. Did not appear in product that do not become coating. 2. Can know coating's existence, that artifact according to radish happens. 3. Quality of the material coating's existence, there was difference of slippage according to radish Conclusion : Quality of the material coating phenomenon that done positioning block thus, it may have to be considered that use after estimate degree that get in image.

자동노출제어장치를 이용한 비정질 실리콘 평판형 검출기에서 격자의 조건에 따른 환자선량 변화와 촬영 거리의 변화가 검출기 획득선량에 미치는 영향

윤석환,최준구,한동균,Yoon, Seok-Hwan,Choi, Jun-Gu,Han, Dong-Kyoon 대한디지털의료영상학회 2007 대한디지털의료영상학회논문지 Vol.9 No.2

This study attempts to propose an appropriate method of using digital medical imaging equipments, by studying the effects of automatic exposure control(AEC), grid ratio and the change of radiography distance on the patient dose and detertor acquisition dose during the procedure of acquiring image through a digital medical imaging detector. The change of dose following the change of grid ratio's exposure and radiography distance was measured, by using an abdominal phantom organized with tissue equivalent materials in an amorphous silicon thin film transistor detecter installed with AWC. The case to use grid ratio 12 : 1, focal distance 180cm to radiography distance 110cm in AEC, the patient dose increased rather when we used grid ration 10 : 1, focal distance 110cm. When AEC was not used,the dose necessary for image acquisition decreased as the grid ratio became higher and the distance became further. but detector acquisition dose was not reduced when in applied AEC. When purchasing digiral medical imaging equipments, optional items such as AEC and grid shall be accurately selected to satisfy the use of the equipments. Radiography error made by radiation technologist and unnenessary patient dose can be reduced by selecting equipments with a radiography distance marker equipment when it did not apply AEC. These equipments can also be helpful in maintaining high imaging quality, one of the merits of digital detectors.

인구 분포에 따른 방사선 장비 및 종사자에 관한 고찰

윤철호,최준구,Yoon, Chul-Ho,Choi, Jun-Gu 대한방사선치료학회 2009 대한방사선치료학회지 Vol.21 No.2

Purpose: The purpose of this paper is to provide basic data in order to systemize the management of demand and supply of radiologic technicians, to pursue a fair regional distribution of educational institutions, and furthermore to keep reasonable medical treatment and fee. This research was carried out through the investigation of radiologic equipments and technicians according to the distribution of the population. Materials and Methods: We compared and analyzed the correlation between regional population, the number of clinics and hospitals, the number of medical imaging devices, and the number of radiologists and radiologic technicians in 5 cities without "Gu" administrative units in 2008. Results: 27,317 radiologic technicians have been produced since the administration of the national qualifying exam for radiologic technicians. About 18,000 radiologic technicians are currently working. There are 39 colleges or universities with Departments of Radiology and the admission quota is 2,120 students excluding one college. The ratio of radiologic equipments to radiologic technicians is 2.6 to 1. Conclusion: There is a dilemma in which some radiologic technicians fail to find appropriate jobs while some clinics or hospitals are in need of radiologic technicians. This dilemma is due to unreasonable regional discrepancies in pay system and welfare situation, and excessive profit-oriented recruiting system of clinics and hospitals. The increase of students of Radiologic Departments and approval of additional departments will end up with producing superfluous high academic degree holders, which is on the contrary to the government policy to produce more job opportunities. So the policy of increasing Radiologic Departments should be reconsidered.

방사성의약품 검사 시 진단(CT)영상에 미치는 영향

이은혜,이예슬,김가중,최준구,Lee, Eun-Hye,Lee, Ye-Seul,Kim, Gha-Jung,Choi, Jun-Gu 대한디지털의료영상학회 2010 대한디지털의료영상학회논문지 Vol.12 No.2

This research attempts to qualitatively evaluate the intensity change by radiopharmaceuticals and obtain computed tomography using phantom injected with various nuclide. Cylindrical phantom is used for comparing and analysing the effect on diagnosis image during radiopharmaceuticals inspection. Inside of the phantom, water is injected and computed tomography image is scanned. During nuclear medicine invitro, frequently used radiopharmaceuticals, $^{99m}TcO_4$ 20 mCi and $^{18}F$ 14 mCi, is diluted in the water phantom and scanned in the same method. Traverse image obtained by CT scan is divided into six traverse image in the same slice of each scanned image. CT-number(HU) value of 10 measuring point is measured in 2 cm interval based on the center of the phantom. Measured HU value, based on the water phantom, is compared with the image after injecting $^{99m}TcO_4$ and $^{18}F$. Average scale of water is 2.8~1.6 HU, $^{99m}TcO_4$ is 3.0~1.6 HU and $^{18}F$ is 1.2~0 HU. Average of water is $2.3{\pm}0.17$ HU, $^{99m}TcO_4$ is $2.2{\pm}0.85$ HU and F-18 is $0.7{\pm}0.95$ HU. Based on water, reduced value of about 0.1 HU and about 0.5 HU is acquired from $^{99m}TcO_4$ and F-18. Radionuclide used in nuclear medicine inspection utilizes 100~200 KeV energy and obtains image through scintillation camera and PET-CT utilizes 511 KeV positron annihilation energy to obtain image. What we learned from this research is that gamma rays from these energies used in CT scan for diagnosis purpose or radioactive therapy plan can change the intensity of the image. The nuclear medicine inspection for reducing the effect of emitted gamma ray diagnosis image should be obtained after a period of time considering half-life which would be reduced distortion or changed in image.