• 정보처리학회논문지A
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• 제10A권2호
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• pp.157-164
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• 2003

최근 볼륨 그래픽스가 의료 영상의 해석 도구로서 주목을 받아 오고 있다. 볼륨 그래픽스에서는 가시화를 위하여 복셀로 정의된 물체가 필요하다. 이 때문에 기하학적인 방법으로 정의한 다각형 및 곡면을 복셀 기반의 물체로 변환시키는데 이를 복셀화(voxelization)라고 한다. 기하학적인 물체를 복셀화하면 기하학적 물체 데이터를 샘플링 데이터와 함께 단일화된 방법으로 볼륨 렌더링할 수 있다. 본 논문에서는 큐브의 단면을 이용한 복셀화의 한 기법을 제안한다. 그리고 개인용 컴퓨터 환경에서 이 기법을 구현한 후에 단순한 기하학적인 데이터를 이용해서 평가하여 논리적인 타당성을 조사한다. 이 기법은 변환된 복셀로부터 정확한 법선 벡터를 계산할 수 있고 복셀간에 구멍(hole)이 발생하지 않고 다해상도(multi-resolution) 표현이 가능한 특성을 가지고 있다.

• Journal of International Society for Simulation Surgery
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• 제1권2호
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• pp.75-79
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• 2014

Purpose The region growing has a critical problem that it often extract vessels with unexpected objects such as a bone which has a similar intensity characteristics to the vessel. We propose the new method to extract arterial vascular anatomy around the stomach from the CTA volume without the post-processing. Materials and Methods Our method, which is also based on the region growing, requires the two seed points from the use. I automatically extracts perigastric arteries using the adaptive region growing method and it does not need any post-processing. Results The three region growing based methods are used to extract perigastric arteries - the conventional region growings with restrict and loose thresholds each and the proposed method. The 3D visualization from the result of our method shows our method extracted the all required arteries for gastric surgery. Conclusion By extracting perigastric arteries using the proposed method, over-segmentation problem that unexpected anatomical objects such as a rib or backbone are also segmented does not occurs anymore. The proposed method does not need to sensitively determine the thresholds of the similarity function. By visualizing the result, the preoperative simulation of arterial vascular anatomy around the stomach can be possible.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.554-556
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• 2011

각종 폐혈관 질환의 발생에 따른 정확하고 빠른 진단의 필요성이 강조되었다. 몇 가지 폐혈관 조영술의 제약사항의 존재로 흉부 CT에 대한 영상 처리의 필요성을 인지하였고 의료 영상처리의 다양성을 위해 ITK를 이용한 폐혈관 분할을 제안하였다. 본 논문은 명암 값을 기반한 방법으로 두 단계의 폐 영역 분할과 혈관 분할의 과정을 수행한다. 각 단계로 폐 영역 분할은 영상 향상, 문턱치 값, 관심영역 잘라내기로 결과 영상을 획득하고 폐 혈관 분할은 획득된 폐 영역에 영역 채우기를 적용하여 얻는다. 분할된 폐혈관 영상을 바탕으로 3차원 시각화 영상을 획득하여 폐혈관에 대한 다양한 관점의 분석 및 진단이 가능할 것으로 판단된다.

• 한국콘텐츠학회논문지
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• 제17권9호
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• pp.32-38
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• 2017

퇴행성 변화를 겪으면서 발생할 수 있는 각종 신체 질환을 포함한, 재활환자들의 보행검사 평가 지표는 환자별 텍스트 형식으로 입력되어 있는 자료들로부터 평가 지표를 얻는다. 본 연구에서는 시간적 정확도 향상을 위하여 환자 개인과 특정 질환 집단의 측정 데이터를 개인, 집단 형식으로 차트 형식으로 시각화함으로써 연구 시 오차 범위를 줄이고, 자료 분석 시간을 감소시켜 효율성을 증대 시키고자 하였다. 또한, 추후 각 분야의 전문의와 협력해 환자 측정 데이터에 따라 의심 질환 제시까지 가능한 의료콘텐츠 소프트웨어로서 개발 가능하도록 하였다.

• Journal of Chest Surgery
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• 제3권2호
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• pp.127-132
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• 1970

A patient was 29 year old house wife who was admitted to the Yonsei University Medical Center on 6 th of Nov., in 1970, with chief complaints of complete loss of bilateral visual acuity, generalized weakness, frequent palpitations, claudication of masseter muscles and intermittent fainting. These symptoms were developed 5 years prior to admission. Physical finding on admission revealed complete loss of bilateral visual acuity, absence of both radial and carotid pulse, but there was good femoral and popliteal pulse. She couldn't open her mouth as she desired and had weakness of mastication. Radiological findings of plane chest PA were not significant. Aortogram(Cineangiogram) showed non-visualization of both carotid and subclavian arteries. It showed only innominate and interal mammary artery preoperatively. The operative findings were as follows: There were complete obliterative changes in both common carotid and subclavian arteries, and periarteritis in the innominate artery. Tube Dacron Prosthesis Bypass with V-arm between innominate artery and both common carotid arteries was performed after thromboendarterectomy. Histopathological finding of the thromboend arterectomy specimen was compatible with pulseless disease, which showed marked fibrous thickening of intima and a diffuse inflammatory cell infiltration of the whole layers. Her postopererative course was uneventful. Follow up aortogram(Cineangiogram) was taken on 11th postoperative day, which revealed both common carotid arteries patent. Her preoperative Subjective symtoms disappeared remarkably, such as her visual acuity improved much, fainting and vertigo disappeared completely and she can go to bath room without difficulty and help. Another patient was 34 year old house wife who was admitted on August, 1964 with chief complaints of frequent fainting and progresive visual loss. She was operated only thromboendarterectomy of both common carotid arteries. Postoperative course was smooth and subjective symptoms were disappeared.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1664-1671
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• 2004

It is necessary to have a model that describes the feature of the knee Joint with a sufficient accuracy. Koreans, however, do not have their own knee joint model to be used in the total knee replacement arthroplasty. They have to use European or American models which do not match Koreans. Three-dimensional visualization techniques are found to be useful in a wide range of medical applications. Three-dimensional imaging studies such as CT(computed tomography) and MRI(magnetic resonance image) provide the primary source of patient-specific data. Three-dimensional knee joint models were constructed by image processing of the CT data of 10 subjects. Using the constructed model, the dimensions of Korean knee joint were measured. And this study proposed a three-dimensional model and data, which can be helpful to develop Korean knee implants and to analyze knee joint movements.

• 대한의용생체공학회:의공학회지
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• 제26권1호
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• pp.23-30
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• 2005

3D virtual endoscopy has been used as an alternative non-invasive procedure for visualization of hollow organs. However, due to computational complexity, this is a time-consuming procedure. In this paper, we propose a fast volume rendering algorithm based on perspective ray casting for virtual endoscopy. As a pre-processing step, the algorithm divides a volume into hierarchical blocks and classifies them into opaque or transparent blocks. Then, in the first step, we perform ray casting only for sub-sampled pixels on the image plane, and determine their pixel values and depth information. In the next step, by reducing the sub-sampling factor by half, we repeat ray casting for newly added pixels, and their pixel values and depth information are determined. Here, the previously obtained depth information is utilized to reduce the processing time. This step is recursively performed until a full-size rendering image is acquired. Experiments conducted on a PC show that the proposed algorithm can reduce the rendering time by 70- 80% for bronchus and colon endoscopy, compared with the brute-force ray casting scheme. Using the proposed algorithm, interactive volume rendering becomes more realizable in a PC environment without any specific hardware.

• 한국임상수의학회지
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• 제35권1호
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• pp.10-12
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• 2018

Mitral regurgitation is the most frequent cause of cardiac disability and death in dogs. A wide range of medical and surgical treatments have been used for mitral regurgitation. Surgical treatments for complete correction of mitral regurgitation include valve repair and valve replacement, which have the advantages of eliminating or correcting the primary cause. Surgical treatments approach the mitral valve via right- or left-side thoracotomy. Aortic root exposure is needed for cardiopulmonary bypass. To compare right-side and left-side approaches, 10 dog cadavers were used in this study. Subsequently, the left-side surgical approach was used in vivo and in conjunction with cardiopulmonary bypass and cardioplegic arrest. Based on the results, and considering ease of access to the aortic root, valve incision site, and visualization of the surgical field, a left-side approach is recommended.

• 대한임상검사과학회지
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• 제50권4호
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• pp.375-381
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• 2018

세포 유전학적 분석은 인간에서의 다양한 종류의 질환을 연구하고 진단하는데 매우 유용하게 사용되고 있다. 지난 수년 동안 세포 유전학적 분석을 통해 매우 의미 있는 결과를 얻을 수 있었으며, 현재 임상검사실에서 일반적인 검사로 확대되어 질병을 진단하고 결과를 평가하는데 매우 유용하게 사용 되고 있다. Microarray는 분자 세포 유전학적인 방법과 기존의 세포유전학적 방법이 융합된 검사방법으로 기존 검사 방법의 단점을 보완하여 유전 관련 질환을 진단하는데 매우 유용하게 사용되고 있다. 따라서 본 논문은 유전질환 진단에 있어 기존의 일반적인 세포유전학적 방법에서 마이크로어레이를 통한 분자세포유전학적 방법으로 어떻게 전환되어 왔는지, 유전 진단을 하는데 앞으로 이 검사방법들이 얼마나 의미 있게 사용될 것인지에 관하여 고찰하였다.

• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1626-1632
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• 2019

Monitoring of environmental radioactivity is essential for ensuring the radiological safety of residents who live near nuclear power plants. Ulsan, South Korea, is surrounded by 16 nuclear power plants, the highest density in the country. In addition, the city contains facilities for conducting radiological nondestructive testing and using radioisotopes for medical purposes. It makes the confirmation of radiological safety particularly necessary. In this study, sampling points were selected based on regional characteristics, and surface water samples were pretreated and analyzed for gross beta and gamma radiation levels. In addition, the distribution of the city's gamma dose rate was determined using a mobile monitoring system and distribution visualization program. The results showed that there is no effect on the gross beta and gamma nuclides of artificial radionuclides, and the gamma dose rate of the entire region did not exceed the environmental radiation level in South Korea overall, confirming the radiological safety of the city.