제6회 막수 포럼 (The 6th Last Wednesday Forum)
일시: 2013년 11월 27일, 11:30~13:00
장소: 전산학과(E3-1) 4층 오상수 영상강의실
Development new biomarker for Alzheimer's disease using multivariate pattern analysis
Presenter: 이영범 (정용 교수님 연구실)
Alzheimer's disease (AD) is the most common degenerative disease. In the clinical view, early diagnosis of AD is an important issue, so we attempt to make a diagnosis method in early stage of the disease. AD has a structural and functional distinct pattern according to the progress of the disease, so classification can be an effective diagnosis tool. For the feature, we focused on the functional network disconnection among specific ROIs. In the resting-state fMRI data, average time course in each ROI is extracted, respectively. With this time course, we can make a correlation matrix which can represent functional network of the brain. Then features (e.g. clustering coefficient, path length and degree) are extracted with this matrix. For the classification, we use the PCA-LDA classifier.
Improving image quality of a mobile Cone-Beam CT by use of scatter and beam-hardening corrections
Presenter: 박미란 (조승룡 교수님 연구실)
Cone-beam computed tomography (CBCT) imaging system has been become widely used in various applications, and takes an important role for diagnosis of emergency patient. However large size of detector causes high scatter-to-primary ratios on CBCT projection data. Also, beam hardening artifacts in reconstructed CT images is resulted by the polychromatic spectrum of X-ray beam. These two phenomena lead unwanted result of reconstructed image such as cupping effect, worse soft tissue contrast, and lower CT grey value. We studies the result of investigation into the effect of the scatter kernel superposition(SKS) method and polynomial beam hardening correction on the measurement soft tissue contrast of head phantom for reconstructed data from half-fan CBCT system. The measurement imaging system was PHION, which is mobile CT system of NanoFocusRay Co., Ltd, and PH-3 angiographic CT head phantom ACS was used for experiments at 120 kVp and 15 mAs. The data was applied scatter correction and beam hardening correction which is a linearization method based on polynomial curves of second order. The image was reconstructed using a filtered back projection algorithm. After scatter and beam hardening correction, contrast to noise ratio of reconstructed images is increased and soft tissues are seen more clearly. Image with scatter correction and beam hardening correction has clear boundary between skull and soft tissues, but only scatter corrected image has unclear boundary.
The study of neutron phase imaging with gratings at HANARO
Presenter: 김종열 (조규성 교수님 연구실)
Grating-based neutron phase-contrast and dark-field imaging techniques using the phase shift and amplitude effect have been developed over the last few years and used for some scientific applications such as bulk magnetic material and microstructure studies.