• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.273-279
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• 2021

Metal material inserted into the body have a large difference in density from human tissues or bones around the Metal during CT scans.. Therefore, the Metal material inserted into the body produces Artifact. Metal Artifact, which occurs around Metals, can degrade the quality of CT images, causing confusion when medical team diagnose lesions. Through this experiment, we confirm that the occurrence of Artifacts decrease by using Dual energy CT and MAR algorithm in Single source Dual energy CT. We also want to present basic data on clinical application methods by comparing and analyzing the characteristics of images obtained by each method. Using GE 750HD CT, artificial implants were scanned using general method and Dual energy. Then we apply the MAR algorithm to each image obtained. And all previously acquired images were compared and analyzed the characteristics of the examination, such as image quality evaluation and dose evaluation. Images with MAR algorithm and Dual Energy confirmed a decrease in Metal Artifact. Images with MAR algorithm have reduced Metal Artifact, but have the disadvantage of distorting the details of artificial joint implants. On the other hand images teseted with Dual Energy have the advantage of being able to implement details than those applied with MAR algorithms, it takes longer to reconstruct the image and the exposure dose was about four times higher than those applied with MAR algorithm. In order to locate Metals, such as the post-operative follow-up period, it is useful to apply MAR algorithm to obtain images. And it is more useful to examine with Dual Energy when micro lesion identification, such as cardiac examination, and surgical planning or when tests are performed in diagnostic way.

• Journal of The Korean Association of Information Education
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• v.20 no.6
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• pp.553-562
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• 2016

Although software education pursues developing learners' computational thinking skills, more studies are needed in terms of designing software education lessons to enhance CT skills and to measure the effects of the lessons. This study aims to investigate the effects of a course designed to enhance pre-service teachers' CT skills by using CT-based teaching materials. Through a literature review the study has selected the five core competencies of CT: algorithmic thinking, evaluation, problem decompositions, abstraction, and generalization. The participants of the study are 47 pre-service teachers who took the one-semester course in a national university of education. A survey was developed and conducted and qualitative analyses on the team projects were performed focusing on the core competencies of CT. The results revealed pre-service teachers' perceived degree of experiencing CT and their competencies represented in their projects. The present study provides important implications to future software education programs in terms of designing and implementing of software education.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.619-621
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• 2003

CT, MRI와 같은 의료 영상을 3차원 재구성을 통해 3차원으로 가시화하는 기술은 의료 분야에서 진단과 진료에 많이 활용되고 있다. 이는 의사에게 정확한 진단과 시술에 대한 확신을 환자에게는 시술에 대한 이해와 신뢰를 심어준다. 치아의 경우 치과 진료가 개개의 치아에 이루어진다는 점을 고려하면 개개의 치아가 개별적으로 모델링 되어 3차원 상에 가시화 되어야 한다. Contour 기반 알고리즘은 2차원 단면 데이터로부터 고속 렌더링과 높은 품질의 3차원 모델 생성이 가능하다. 본 논문에서는 CT에서 추출한 치아 contour 데이터로부터 삼각형 패치를 생성하고, 어금니의 분기 문제를 해결하는 3차원 치아 모델 생성을 위한 contour 기반 알고리즘을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.607-609
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• 2002

본 논문은 흉부 전산화단층촬영 영상에서 폐 영역을 자동으로 분할하는 알고리즘과 폐결절을 자동으로 검출하는 알고리즘에 관한 연구 내용을 담고 있다. 폐 분할 알고리즘은 gray-level thresholding과 morphologic 영상 처리기법을 이용하였고, 폐결절 자동 검출 알고리즘은 추출된 결절 후보의 size, compactness, mean of gray level 값을 분석하여 혈관과 결절을 구분하였다. 개발한 폐결절 자동 검출 시스템은 실험한 영상에 포함된 폐결절 117개 중 55%인 64개를 검출하였고, 3.4 False Positive/section이었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.655-662
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• 2016

We investigated on the usefulness of MAR algorithm by making a comparison of the CT value between before and after applying the MAR algorithm in dual energy CT, using the various kinds of medical metals, causing the artifact to lead to the low image quality. As a result, the artifact was reduced in most cases (P<0.05); in particular, the artifact was highly reduced (P<0.05) using high density material, like alloy-stainless (reduced by 78.1%) and platinum, for example GDC coil (reduced by 76.1%). The effect of decreasing the Black hole artifact was outstanding in both the alloy-stainless and alloy-titanium (P<0.05). However, in case of GDC coil-a type platinum, white streak artifact was reduced effectively (P<0.05). Therefore, in case of patients who have medical metals inserted, we think that high-quality image information can be provided by decreasing the artifact caused by high density material through MAR algorithm in dual energy CT.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.462-464
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• 2018

본 논문은 촬영된 치아의 CT영상에서 치아의 상악과 하악의 분리 알고리즘을 제안한다. 촬영 기기의 노후화, metal artifact, 치아 부정합 등 외부 요인에도 강인한 성능을 보이도록 알고리즘을 설계하였다.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.389-395
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• 2018

The study attempted to use computed tomography images to determine the usefulness of the reduction in the axial reduction algorithm in the event of a metallic artifacts reduction in the image of the beam-hardening effect, which is known as the most effective method of reducing metallic artifact reduction in the image and the reduction of the metal produced in this study. As a result, the result is increased to 140 kVp to reduce the value of the CT value by 0.02 to 0.05 %, resulting in decreased axial effect (P > 0.05). The CT value decreased from 12.4 to 26.9 % when applied to the reduction of the metallic. 12.4 to 26.9 % (p<0.05). In addition, in the qualitative assessment by the clinical trial evaluation, it was assessed as 1.8 points after applying the MAR algorithm, In the resolution of resolution and contrast evaluations, the estimation of the decrease in metallic artifact effects was assessed as the metal was assessed to be scored 7.2 points after the MAR algorithm was evaluated. Therefore, in case of artifacts due to irreversible beam hardening effect, it is useful to reduce artifacts caused by beam hardening effect by using various methods derived from existing researches and scanning by applying the metal artifact reduction algorithm proposed in this experiment.

• Progress in Medical Physics
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• v.23 no.4
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• pp.252-260
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• 2012

The reduction of radiation dose from x-ray is a main concern in computed tomography (CT) imaging due to the side-effect of the dose on human body. Recently, the various methods for dose reduction have been studied in CT and one of the method is a iterative reconstruction based on total variation (TV) minimization at few-views data. In this paper, we evaluated the image quality between total variation (TV) minimization algorithm and Feldkam-Davis-kress (FDK) algorithm in micro computed tomography (CT). To evaluate the effect of TV minimization algorithm, we produced a cylindrical phantom including contrast media, water, air inserts. We can acquire maximum 400 projection views per rotation of the x-ray tube and detector. 20, 50, 90, 180 projection data were chosen for evaluating the level of image restoration by TV minimization. The phantom and mouse image reconstructed with FDK algorithm at 400 projection data used as a reference image for comparing with TV minimization and FDK algorithm at few-views. Contrast-to-noise ratio (CNR), Universal quality index (UQI) were used as a image evaluation metric. When projection data are not insufficient, our results show that the image quality of reconstructed with TV minimization is similar to reconstructed image with FDK at 400 view. In the cylindrical phantom study, the CNR of TV image was 5.86, FDK image was 5.65 and FDK-reference was 5.98 at 90-views. The CNR of TV image 0.21 higher than FDK image CNR at 90-views. UQI of TV image was 0.99 and FDK image was 0.81 at 90-views. where, the number of projection is 90, the UQI of TV image 0.18 higher than FDK image at 90-views. In the mouse study UQI of TV image was 0.91, FDK was 0.83 at 90-views. the UQI of TV image 0.08 higher than FDK image at 90-views. In cylindrical phantom image and mouse image study, TV minimization algorithm shows the best performance in artifact reduction and preserving edges at few view data. Therefore, TV minimization can potentially be expected to reduce patient dose in clinics.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.749-752
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• 2004

CT 영상에서 폐암 추출을 위한 컴퓨터지원진단시스템(CAD)에서 전처리 시스템은 매우 중요한 역할을 담당한다. 본 논문에서는 CT 영상에서 폐암 추출을 위한 전처리 기법을 소개한다. CT 영상에서 폐 영역 추출 과정에서 가장 먼저 수행되는 이진화를 위해 k-means 클러스터링 알고리즘을 이용하고, 비관심 영역 제거 방법으로 연결요소를 분석하고, 이진화 과정에서 발생한 폐 외곽 분실을 재구성하기 위해 Rolling Ball 알고리즘을 수행한다. 또한 분할된 폐 영역에서 폐암 후보자를 선출하기 위해 분할과정에서 수행하였던 이진화 방법을 폐 영역에 다시 한번 적용하고 잡음제거를 위해 모폴러지 기법을 사용한 전처리 기법을 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.243-252
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• 2018

In this paper, we propose a bone region extraction method using a snake algorithm and a particle filter in CT image. We extract the bone outline using the snake algorithm, and extract the bone area by moving the particle filter along this outline. If other bones are in close proximity to the bone outline, the snake algorithm may not be able to extract the bone outline completely. At this time, the particle filter extracts the bone area while compensating for the error. In this paper, we compared the proposed method with the conventional morphological processing method. The result is similar when other bones are not close to the bone area to be extracted. However, if other bones are close to each other, The accuracy of the proposed method is higher than the conventional morphological processing method.