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병리특이적 형태분석 기법을 이용한 HRCT 영상에서의 새로운 봉와양폐 자동 분할 방법
김영재 ( Young Jae Kim ),김태윤 ( Tae Yun Kim ),이승현 ( Seung Hyun Lee ),김광기 ( Kwang Gi Kim ),김종효 ( Jong Hyo Kim ) 한국정보처리학회 2012 정보처리학회논문지. 소프트웨어 및 데이터 공학 Vol.1 No.2
Honeycombs are dense structures that small cysts, which generally have about 2~10 mm in diameter, are surrounded by the wall of fibrosis. When honeycomb is found in the patients, the incidence of acute exacerbation is generally very high. Thus, the observation and quantitative measurement of honeycomb are considered as a significant marker for clinical diagnosis. In this point of view, we propose an automatic segmentation method using morphological image processing and assessment of the degree of clustering techniques. Firstly, image noises were removed by the Gaussian filtering and then a morphological dilation method was applied to segment lung regions. Secondly, honeycomb cyst candidates were detected through the 8-neighborhood pixel exploration, and then non-cyst regions were removed using the region growing method and wall pattern testing. Lastly, final honeycomb regions were segmented through the extraction of dense regions which are consisted of two or more cysts using cluster analysis. The proposed method applied to 80 High resolution computed tomography (HRCT) images and achieved a sensitivity of 89.4% and PPV (Positive Predictive Value) of 72.2%.
김광기,Kim, Kwang-Gi 대한의용생체공학회 2009 의공학회지 Vol.30 No.4
Recently, robot research and development was interesting the inside and outside of the country. Medical robot surgery showed diverse advantages according to advanced technical robot research. Also the academic society, research institute and industry showed concerning to the medical robot system. There is a growing need to introduce medical research for aging society. The surgical landscape is quickly changing because of the major driving force of robotics. Robot system and biomedical engineering research as defined a new engine of development show present ways of future revitalization of medical robot system. Medical robot system will be even more utilized when we keeps trying to combine high biomedical technique, IT research, and robot technique. In this review article, we begin with a short historical review of medical robotics, followed by an overview of clinical applications where robots have been applied.
수밀성능 증진용 혼화제를 혼입한 콘크리트의 미세구조 변화가 압축강도 및 흡수특성에 미치는 영향에 관한 연구
김광기(Kim Kwang-Ki),권미옥(Kweun Mi-Ok),임남기(Lim Nam-Gi),정상진(Jung Sang-Jin) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.3
Among the factors of concrete deterioration, water infiltration accelerates early deterioration caused by the deterioration factors mentioned above. The watertightness of concrete is improved through the use of various binders and expansive admixtures as well as special types of cement designed for high durability. Recently, aiming at high waterproofness and durability, research is being made on waterproof admixtures that can be added before the placement of ready-mixed concrete and increase the waterproofness of the concrete and such waterproof admixtures emphasize the effect of high waterproof performance through improvement in the density of fire pore in concrete. However, because they are added to unhardened concrete, they may affect the physical properties of the concrete and there have been few researches on the characteristics of waterproof admixtures. In order to measure waterproofness in the use of waterproof admixtures, the present study examined resistanceto water infiltration through the addition of admixtures based on basic physical properties, and for this we conducted permeability tests using forced pressure according to the age of specimen and experiment on resistance to water absorption in the open air according to curing condition. According to the results of this study, waterproofness resulting from the addition of waterproof materials was determined by the initial age and it was found that the curing condition of specimens affects resistance to water infiltration. Also, in comparison with specimens without waterproof admixture, specimens containing waterproof admixture showed improvement in water resistance by around 30% in each condition.
경항문 내시경 수술 도구에서의 최적 활동 반경 개선을 위한 컴퓨터 시뮬레이션 연구
김형태,김광기,남경원,김현호,손대경,Kim, Hyung-Tae,Kim, Kwang-Gi,Sohn, Dae-Kyung,Kim, Hyun-Ho,Nam, Kyoung-Won 대한의용생체공학회 2009 의공학회지 Vol.30 No.6
Conventional devices for transanal endoscopic microsurgery that are currently used clinically for intestine or rectal cancer patients have 40 mm external diameter of rectoscope tube - induces anal damage and long-term postoperative pain for small-sized patients. In this paper, we designed rectum and rectoscope models and calculated the changing trends of operation area of the surgical tools in accordance with the step-by-step variation of design parameters of the rectoscope tube - external diameter, axial length, and distal angle. Using the results of computer simulation, we suggested an optimal set of design parameters that minimizes external diameter of the rectoscope tube and at the same time, maintains similar operation area of the surgical tools compared with commercialized devices (${\geq}\;4274.7mm^2$). The results of the simulation showed that the optimal design parameters were 35 mm external diameter, 100 mm axial length, and $45^{\circ}$ distal angle of the rectoscope tube. This result can be applied to the development of endoscopic microsurgery device that can minimize side effects to the intestine or rectal cancer patients.
유방암 환자의 감시림프절 생검을 위한 림포신티그라피와 실사영상의 합성
정창부,김광기,김태성,김석기,Jeong, Chang-Bu,Kim, Kwang-Gi,Kim, Tae-Sung,Kim, Seok-Ki 대한의용생체공학회 2010 의공학회지 Vol.31 No.2
This paper presents a method that registers a lymphoscintigraphy to the real image captured by a CMOS camera, which helps surgeons to easily and precisely detect sentinel lymph nodes for sentinel lymph node biopsy in breast cancer patients. The proposed method consists of two steps: pre-matching and image registration. In the first step, we localize fiducial markers in a lymphoscintigraphy and a real image of a four quadrant bar phantom by using image processing techniques, and then determines perspective transformation parameters by matching with the corresponding marker points. In the second step, we register a lymphoscintigraphy to a real images of patients by using the perspective transformation of pre-matching. To examine the accuracy of the proposed method, we conducted an experiment with a chest mock-up with radioactive markers. As a result, the euclidean distance between corresponding markers was less than 3mm. In conclusion, the present method can be used to accurately align lymphoscintigraphy and real images of patients without attached markers to patients, and then provide useful anatomical information on sentinel lymph node biopsy.
초음파 수술기의 수술 효율성 향상을 위한 진동자 임피던스 측정에 따른 조직 분류 연구
김홍래,김성천,김광기,김영우,Kim, Hong Rae,Kim, Sung Chun,Kim, Kwang Gi,Kim, Young-Woo 대한의용생체공학회 2013 의공학회지 Vol.34 No.3
Ultrasonic shears is currently in wide use as an energy device for minimal invasive surgery. There is an advantage of minimizing the carbonization behavior of the tissue due to the vibrational energy transfer system of the transducer by applying a piezoelectric ceramic. However, the vibrational energy transfer system has a pitfall in energy consumption. When the movement of the forceps is interrupted by the tissue, the horn which transfers the vibrational energy of the transducer will be affected. A study was performed to recognize different tissues by measuring the impedance of the transducer of the ultrasonic shears in order to find the factor of energy consumption according to the tissue. In the first stage of the study, the voltage and current of the transducer connecting portion were measured, along with the phase changes. Subsequently, in the second stage, the impedance of the transducer was directly measured. In the final stage, using the handpiece, we grasped the tissue and observed the impedance differences appeared in the transducer To verify the proposed tissue distinguishing method, we used the handpiece to apply a force between 5N and 10N to pork while increasing the value of the impedance of the transducer from 400 ${\Omega}$.. It was found that fat and skin tissue, tendon, liver and protein all have different impedance values of 420 ${\Omega}$, 490 ${\Omega}$, 530 ${\Omega}$, and 580 ${\Omega}$, respectively. Thus, the impedance value can be used to distinguish the type of tissues grasped by the forceps. In the future study, this relationship will be used to improve the energy efficiency of ultrasonic shears.
손재범,김광기,Son, Jaebum,Kim, Kwang Gi 대한의용생체공학회 2012 의공학회지 Vol.33 No.3
Biopsy is a type of histopathological examinations, in which a physician samples cells or tissues from a patient's suspicious lesion. Such a lesion frequently resides deep inside human body, and then a percutaneous biopsy is therefore performed using a thick needle with the assistance of medical imaging such as computed tomography(CT) and magnetic resonance imaging(MRI). Recently modern robotic technology is being introduced to percutaneous biopsy in order to reduce any possible human error and hazard on physicians caused by medical imaging. After medical imaging locates the exact location of lesion, an optimization algorithm plans the path for a biopsy needle. Subsequently, a robot system moves the biopsy needle to the lesion in accurate and safe way with the control of a practitioner or automatically. In this article, we try to look into the state-of-art of percutaneous biopsy using such robotic technology. We classified percutaneous biopsy robots by mechanical characteristics and by imaging technology. Then, advantage and disadvantage of each class type are described as well as the basic description, and a few representative designs for each type are introduced. Current research issues of robotized percutaneous biopsy are subjectively selected for the readers' convenience. We emphasize the basic technology of actuator and sensors compatible with imaging technology to conclude this review.