• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.281-285
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• 2011

We investigated the effects of tunneling current on scanning tunneling microscopy (STM) images of 1-octanethiol (OT) and 1-decanethiol (DT) self-assembled monolayers (SAMs). At a low tunneling current, the domain boundaries and ordered alkanethiol molecules were clearly resolved. As the tunneling current was increased at a constant bias voltage, however, the STM images showed disordered structures of the OT and DT SAMs. As the tunneling current was reduced back to low values, the ordered structures of the alkanethiol molecules reappeared. The reversibility of the process suggests that the sulfur head groups did not rearrange under any of the tunneling current conditions. On the basis of our observations, which are inconsistent with the standard model for STM imaging of molecules on metal surfaces, we consider the STM imaging mechanism in terms of a two-region tunneling junction model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.879-884
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• 2012

Photoacoustic Tomography (PAT) is a promising medical imaging modality by reason of its particularity. It combines optical imaging contrast of optical imaging with the spatial resolution of ultrasound imaging and can demonstrate change of biological feature in an image. For that reason, many studies are in progress to apply this technic for diagnosis. But, real-time PAT system is necessary to confirm a biological reaction induced by external stimulation immediately. Thus, we developed a real-time PAT system using linear array transducer and self-developed Data acquisition board (DAQ) resources, To evaluate the feasibility and performance of our proposed system, two type of phantom test were also performed. As a result of those experiments, the proposed system shows enough performance and confirm its usefulness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1167-1187
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• 2020

With the development of medical imaging technology, image registration has been widely used in the field of disease diagnosis. The registration between different modal images of brain magnetic resonance (MR) is particularly important for the diagnosis of brain diseases. However, previous registration methods don't take advantage of the prior knowledge of bilateral brain symmetry. Moreover, the difference in gray scale information of different modal images increases the difficulty of registration. In this paper, a multimodal medical image registration method based on image segmentation and symmetric self-similarity is proposed. This method uses modal independent self-similar information and modal consistency information to register images. More particularly, we propose two novel symmetric self-similarity constraint operators to constrain the segmented medical images and convert each modal medical image into a unified modal for multimodal image registration. The experimental results show that the proposed method can effectively reduce the error rate of brain MR multimodal medical image registration with rotation and translation transformations (average 0.43mm and 0.60mm) respectively, whose accuracy is better compared to state-of-the-art image registration methods.

• Journal of radiological science and technology
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• v.41 no.1
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• pp.33-38
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• 2018

There are limits to check the lesion as inserting a breast implant patients. So the application of BSGI based on Nuclear Medicine examination has increased. In this study, therefore we confirmed the effect of the image applying to breast implants in Breast Specific Gamma Imaging. We utilized Dilon 6800 BSGI scanner and developed the phantom. The self-development phantom was a rectangular shape of $230{\times}190{\times}80mm$ size and had 5 spheres which consisted of diameters of 10, 13, 17, 22, 28 mm in central part. We injected $^{99m}TcO_4$ into the self-development phantom in the proportion of four to one and made each additional phantom filled with 0.9 % sodium chloride, silicon and paraffin. Each additional phantom was placed between detector and self-development phantom. Each image was acquired five times depending on the type and thickness of the additional phantom. Statistical analysis with SPSS ver.18 was applied. In the test of variation according to the thickness of all additional phantoms, as the phantoms which 0.9% sodium chloride, silicon and paraffin increased, the attenuation variation was higher(P<0.005). There was no significant difference in the attenuation variation and the quality of image for type of the additional phantom. Therefore, if the effect of the image applying to breast implants in Breast Specific Gamma Imaging is confirmed, the higher diagnostic value can be achieved.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.1
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• pp.25-31
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• 2017

Liposomes are defined as spherical, self-closed structures formed by lipid bilayers containing aqueous phase. Most liposomes are composed of various amphipathic lipids such as phospholipids and cholesterol. We used amphipathic lipids (DPPC, DPPG) as liposome components and prepared around 100 nm liposomes by standard extrusion method. Nuclear/MR dual imaging agents based on liposome platform were prepared by adding radioactive $^{131}I$-HIB (hexadecyl-4-tributylstannylbenzoate) and Gd-DTPA into liposome bilayer and inside liposome, respectively. Gamma camera and MR imaging both showed signal increases in liver.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.319-324
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• 2005

To date, more than 150 exo-solar planets have been observed by various methods such as spectroscopic, photometric, astrometric, gravitational lensing, pulsar timing methods. However, all these are indirect methods; they do not directly image the planets. Only free-floating planets or their 'ana-log' have been directly detected so far. Thus the next milestone is the direct imaging of any kinds of planetary mass objects orbiting around normal (young) stars, which might have been associated with protoplanetary disks, the sites of planet formation. I will describe some SUBARU efforts to detect self-luminous young giant planets as companions as well as direct imaging of the protoplanetary disks of ${\~}$100 AU size. The results of near-infrared coronagraphic imaging with adaptive optics are briefly presented on AB Aur, HD 142527, T Tau, and DH Tau. Our results demonstrate the importance of high-resolution (${\~}$0.1 arcsec) direct imaging over indirect observations such as modeling based on spectral energy distributions. The SUBARU observations are a prelude to ALMA from the morphological point of view.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.1-6
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• 2013

This study is to provide clinical data when reverse-water's-view was carried out about pediatric who did not communicate by applying self-development jaw lift tool. This study were conducted in a subject of 23 children who examined revers-water's-view from 2013 July 6 to 2013 August 5 at our hospital. Two group time which were carried out revers-water's with tool and without tool were measured. also, Image of two group were evaluated. Evaluation data obtained by measuring the average difference were analyzed by independent-t-test. After apply self-development-jaw-lift-tool, time was reduced by 35.2%(36.6sec). the results indicated significant differences(p< .05). Image evaluation was increase 43.5%(1.03point), It was statistically highly significant difference (p< .01). If apply self-development-jaw-lift-tool in pediatric revers-water's-view, operator can provide fast, convenience, high quality image to pediatric.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.251-254
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• 2001

본 논문에서는 Self Organizing Map을 이용하여 fMRI data를 분석해 보았다. fMRl (functional Magnetic Resonance Imaging)는 인간의 뇌에 대한 비 침투적 연구 방법 중 최근에 각광받고 있는 것이다. Motor task를 수행하고 있는 피험자로부터 image data를 얻어내어 SOM을 적용하여 clustering한 결과 motor cortex 영역이 뚜렷하게 clustering 되었음을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1169-1173
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• 2006

Imaging ellipsometry (IE) for detection of binding of Escherichia coli O157:H7 (E. coli O157:H7) to an immunosensor is reported. A protein G layer, chemically bound to a self-assembled layer of 11-mercaptoundecanoic acid (11-MUA), was adopted for immobilization of monoclonal antibody against E. coli O157:H7 (Mab). The immobilization of antibody was investigated using surface plasmon resonance. To fabricate antibody spots on a gold surface, protein G solution was spotted onto the gold surface modified with an 11-MUA layer, followed by immobilizing Mab on the protein G spot. Ellipsometric images of the protein G spot, the Mab spot, and Mab spots with binding of E. coli O157:H7 in various concentrations were acquired using the IE system. The change of mean optical intensity of the Mab spots in the ellipsometric images indicated that the lowest detection limit was $10^3$CFU/ml for E. coli O157:H7. Thus, IE can be applied to an immunosensor for detection of E. coli O157:H7 as a detection method with the advantages of allowing label-free detection, high sensitivity, and operational simplicity.

• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.227-234
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• 2002

This study was conducted to nondestructively estimate the volumetric information of peach and pit and to visualize the 3D information of internal structure from magnetic resonance imaging(MRI) data. Bruker Biospec 7T spectrometer operating at a proton reosonant frequency of 300 MHz was used for acquisition of MRI data of peach. Image processing algorithms and visualization techniques were implemented by using MATLAB (Mathworks) and Visualization Toolkit(Kitware), respectively. Thresholding algorithm and Kohonen's self organizing map(SOM) were applied to MRI data fur region segmentation. Volumetric information were estimated from segemented images and compared to the actual measurements. The average prediction errors of peach and pit volumes were 4.5%, 26.1%, respectively for the thresholding algorithm. and were 2.1%, 19.9%. respectively for the SOM. Although we couldn't get the statistically meaningful results with the limited number of samples, the average prediction errors were lower when the region segmentation was done by SOM rather than thresholding. The 3D visualization techniques such as isosurface construction and volume rendering were successfully implemented, by which we could nondestructively obtain the useful information of internal structures of peach.