Seok-Yoon Choi

Development of automatized new indices for radiological assessment of chest-wall deformity and its quantitative evaluation

Pre-operative diagnosis of chest-wall deformity is important for successful surgical correction and post-operative evaluation of funnel chest patients. However, conventional indices that define the severity of deformity have several limitations; manually calculated and cannot supply information about asymmetry. We developed four indices that can represent both the depression and the asymmetry of the chest-wall, and can automatically be extracted by computerized image processing technique. Three indices, including eccentricity index (EI), flatness index (FI), and circularity index (CI), were suggested to represent the depression of the chest-wall, and one index, rotation index (RI), to represent the asymmetry of the chest-wall. To verify the feasibility of new indices, several synthetic images and real CT images were used to analyze the performance of new indices and the statistical relationship with conventional Haller index. The experimental results showed possible application of suggested indices to the diagnosis of funnel chest patient. Suggested indices showed clear trends of change with the severity of chest-wall deformation in regards to both the depression and the asymmetry. Results of statistical analysis showed high correlation between new indices and HI, showing possibility of replacing HI.

Segmentation of the left ventricle in myocardial perfusion SPECT using variational level set formulation

Myocardial scintigraphy is an imaging modality which provides functional information. We used myocardium SPECT images performed at stress and rest with Tc-99m MIBI. The myocardial perfusion is estimated by comparing images at two different instant rest and stress and it is indicated when ischemia is from the normal case suspected. The diagnosis is obtained by comparing the topology of myocardium blood flow at these different instants. Shape instabilities have been an important problem, particularly in 3D. Since then, different approaches to the solution of this problem have been developed, we proposed an variational level set based on Mumford-Shah segmentation techniques and the variational level set method. Its strategy is first searching the object in the dataset. For tracing its exact contour, we can detect objects whose boundaries are not necessarily defined by gradient or with very smooth boundaries, for which the classical active contour models are not applicable. This segmentation method was fast and robust on noisy, low-resolution data. Rendered surface of the endocardium and epicardium wall at stress and rest the contours of heart are very well detected and preserved. The method could be used to extract quantitative functional parameters.

Computer-Aided Diagnosis for Liver Cirrhosis using Texture features Information Analysis in Computed Tomography

Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules leading to loss of liver function. Liver Cirrhosis is most commonly caused by alcoholism, hepatitis B and C, and fatty liver disease, but has many other possible causes. Some cases are idiopathic disease from unknown cause. Abdomen of liver Computed tomography(CT) is one of the primary imaging procedures for evaluating liver disease such as liver cirrhosis, Alcoholic liver disease(ALD), cancer, and interval changes because it is economical and easy to use. The purpose of this study is to detect technique for computer-aided diagnosis(CAD) to identify liver cirrhosis in abdomen CT. We experimented on the principal components analysis(PCA) algorithm in the other method and suggested texture information analysis(TIA). Forty clinical cases involving a total of 634 CT sectional images were used in this study. Liver cirrhosis was detected by PCA method(detection rate of 35%), and by TIA methods(detection rate of 100%-AGI, TM, MU, EN). Our present results show that our method can be regarded as a technique for CAD systems to detect liver cirrhosis in CT liver images.

Evaluation of Present Curriculum for Devlopment of Dept. of Radiological Science Curriculum

A curriculum of study demands a change as period of time and society evolve. Therefore, at this point where changes are required, this study is to analyze and evaluate the curriculums which will enhance and improve current studies as a preceding stage. The research was based on the survey by groups of education experts and 19 universities with current curriculum of study in radiologic science, and their references. The study was focused on the scope of work by radiologic technologist, change of college systems, academic research about radiologic science, and the improvement and the future of radiologic science field in perspective to globalization and the digital era. In terms of work scope, angiography and interventional radiology at 6 to 8 schools, fluoroscopy at 4 schools, ultrasound and practices at 6 schools, magnetic resonance image at 2 schools were found to be unestablished. The basic medical subjects, humuan physiology, human anatomy and practices, medical terminology courses were set up at most schools; however, pathology at 5 schools, image anatomy at 6 schools, clinical medicine at 11 schools were yet opened. Among the basic science and engineering subjects, general biology and its practices at 11 schools, general physics and its practices at 14 schools, and general chemistry and its practices at 8 schools were established which is about a half from a total number of schools. Only 4-5 schools established digital subjects such as, health computer, computer programming, PACS which are the basic major subjects. In order to provide academic improvement in radiologic science, digitalized education and globalization, and basis for future-oriented education for the field of radiologic science, including expanded scope of work, it is acknowledged that curriculums that are opened and run at each school need to be standardized. Therefore, the need for introduction of certificate for the radiologic science education courses are suggested.

An Analysis of Learner Satisfaction and Effectiveness Regarding `Center for Teaching and Learning Support`

In this study, we analyzed student satisfaction and effectiveness regarding the Center for Teaching and Learning Support where students are using educational information. Based on the analysis, the purpose of this study was to identify the requirements for the improvement to enhance the educational support by the Center for Teaching and Learning Support. As a result, it was shown that satisfaction and effectiveness as well as requirement for improvement were different depending on school level. Therefore, it is necessary for the Center to enhance the services appropriate for each school level rather than unified services. In other words, the improvement is required to enhance the fun and interesting aspects for elementary and middle school students, and the effort is required to enhance the quality aspect of information for high school students when educational information is provided.

The Objective Image Analysis for HCC and HH with a Axial Image of Liver CT Scan

Liver CT 검사에서 간세포암과 간혈관종의 구별은 악성종양과 양성종양을 구별하여 치료방법을 결정 하는 것에 있어서 중요한 검사 방법 중 하나이다. 현재 사용되는 방법은 전문의의 주관적인 해석에 의해 판독이 이루어지고 있으며, 추가적인 해석을 위해 본 연구에서는 객관적인 방법을 제시하고자 한다. 조영 제 주입 후 검사시간은 조영주입전기(Pre), 동맥기(35sec), 문맥기(70sec), 지연기(180sec)로 하였다. 조영증강패턴변화(Enhancement Pattern) 에서 간세포암의 일반적인 패턴변화는 26.6% 로 관찰 되었 다. 간혈관종의 일반적인 패턴변화는 16.6%로 관찰 되었다. 간세포암과 간혈관종의 HU(Hounsfield unit) 값 변화를 관찰하기 위해 각각의 시간별 평균값과 표준편차를 확인한 결과 Lesion부위의 artery-portal차 이가 가장 큰 것으로 나타났다. (간세포암 19.76±23.52, 간혈관종 60.23±29.43). 간세포암 에서 76.6%, 간혈 관종 에서 80.0%가 일치하게 나타났다. 본 연구를 통해 HCC와 HH의 객관적 분석 지표로 HU값 을 제안 하고 분석방법을 임상에 사용 한다면 진단에 도움을 줄 것이다.

Evaluation of Setup When Using C-Rad System in Radiotherapy

In radiotherapy, accurate patient positioning and set up are important factor that treatment can influence success. In generally, the 3-laser system is used when the patient set up. But today the body surface scanning system(C-Rad system) is trying to use. Compare and evaluate the C-Rad system and the 3-laser system to check availability. Head and neck that are no movement of internal organs and easy to apply fixation device are limited. Alderson Rando anthropomorphic phantom and 10 patients who have lesions of head and neck are targeted. C-RAD system`s setup error mean and standard deviation are the X axis(), Y axis(), Z axis() in the phantom study, and in the patient study X axis(), Y axis() Z axis(). So C-RAD system is better than 3-laser system mostly, but C-RAD system`s error rate is a little worse than 3-laser system in the Z axis. When radiation treatment of head and neck, body surface contour scanning system contribute to correct positioning and minimize the set up error.

Evaluation of Image Quality and dose with the Change of kVp and BMI in the Liver CT

CT for follow-up visits because of liver disease, body mass index (BMI) and kVp according to the change of the image quality and radiation dose to evaluate for changes. March 2010 to June 2011 at Pusan P University Hospital, abdominal CT scans a patient BMI (Body Mass Index. Less BMI) index was less than 25 in the treatment of subjects had a 48-person Noise and SNR at 100kVp abdominal image is lager than the 120kVp image. CTDI volume value at by the analysis of the radiation dose is 4.47mGy(100kVp) and 9.01mGy(120kVp). So CTDIvol in 100kVp is smaller than CTDIvol in 120kVp(decrease by 44.1%). And, effective dose is 7.1mSv(100kVp) and 12.51mSv(120kVp). So effective dose in 100kVp is smaller than effective dose in 120kVp(decrease by 43%). Evaluation of image quality is that Unacceptable 0 person, Suboptimal 0 person, Adequate 0 person, Good 1 person, Excellent 47 person. In case of repeatly patient, we examinate abdomianl CT scan by using low kVp and body mass index less than 25. We can has good quality image and benefit of low radiation dose.

Domestic and International Graduate School Education in the Radiological Science : Status and Analysis

The impotance of Radiological science is greater due to development of Science and technology in Medical and Engineering. people who research specific area thought interdisciplinary approach, convergence is essential to pioneer a new field, receive attention was that interdisciplinary approach was needed. so investigating graduate system of radiological science, advanced country, designed to fit their country, could propose reference. the results show, in the university of offered with Master Degree operated program for Clinical experts(Sonography Specialist, Radiation Theraphy Specialist and Nuclear Medicine Specialist)and offered with Ph.D Degree operated program for Scientist and physicist (Nuclear Scientist, Medical Physicist). Note that by this, advanced graduate school program will enable us to become a reader of academia, play a leading role in the world.