• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2367-2370
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• 2014

"Cat's eye"-shaped $[^{57}Co]CoO@SiO_2$ core-shell nanostructure was prepared by the reverse microemulsion method combined with radioisotope technique to investigate a potential imaging agent for a single photon emission computed tomography (SPECT) in nuclear medicine. The core cobalt oxide nanorods were obtained by thermal decomposition of $Co-(oleate)_2$ precursor from radio isotope Co-57 containing cobalt chloride and sodium oleate. The $SiO_2$ coating on the surface of the core cobalt oxide nanorods was produced by hydrolysis and a condensation reaction of tetraethylorthosilicate (TEOS) in the water phase of the reverse microemulsion system. In vivo test, micro SPECT image was acquired with nude mice after 30 min of intravenous injection of $[^{57}Co]CoO@SiO_2$ core-shell nanostructure.

• Journal of Gastric Cancer
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• 제10권4호
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• pp.188-195
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• 2010

Purpose: This study was done to evaluate the usefulness of preoperative computed tomography (CT) and intraoperative laparoscopic ultrasound to facilitate treatment of gastric submucosal tumors. Materials and Methods: The feasibility of laparoscopic wedge resection as determined by CT findings of tumor size, location, and growth pattern was correlated with surgical findings in 89 consecutive operations. The role of laparoscopic ultrasound for tumor localization was analyzed. Results: Twenty-three patients were considered unsuitable for laparoscopic wedge resection because of large tumor size (N=13) or involvement of the gastroesophageal junction (N=9) or pyloric channel (N=1). Laparoscopic wedge resection was not attempted in 11 of these patients because of large tumor size. Laparoscopic wedge resection was successfully performed in 65 of 66 (98.5%) patients considered suitable for this procedure. Incorrect interpretation of preoperative CT resulted in a change of surgery type in seven patients (7.9%): incorrect CT diagnosis on gastroesophageal junction involvement (N=6) and on growth pattern (N=1). In 18 patients without an exophytic growth pattern, laparoscopic ultrasound was necessary and successfully localized all lesions. Conclusions: Preoperative CT and laparoscopic ultrasound are useful for surgical planning and tumor localization in laparoscopic wedge resection.

• Journal of Korean Neurosurgical Society
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• 제47권2호
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• pp.89-94
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• 2010

Objective : To evaluate the role of cranial sonography and computed tomography in the diagnosis of neonatal intracranial hemorrhage and hypoxic-ischemic injury in an Indian set-up. Methods : The study included 100 neonates who underwent cranial sonography and computed tomography (CT) in the first month of life for suspected intracranial ischemia and hemorrhage. Two observers rated the images for possible intracranial lesions and a kappa statistic for interobserver agreement was calculated. Results : There was no significant difference in the kappa values of CT and ultrasonography (USG) for the diagnosis of germinal matrix hemorrhage/intraventricular hemorrhage (GMH/IVH) and periventricular leucomalacia (PVL) and both showed good interobserver agreement. USG, however detected more cases of GMH/IVH (24 cases) and PVL (19) cases than CT (22 cases and 16 cases of IVH and PVL, respectively). CT had significantly better interobserver agreement for the diagnosis of hypoxic ischemic injury (HII) in term infants and also detected more cases (33) as compared to USG (18). CT also detected 6 cases of extraaxial hemorrhages as compared to 1 detected by USG. Conclusion : USG is better modality for imaging preterm neonates with suspected IVH or PVL. However, USG is unreliable in the imaging of term newborns with suspected HII where CT or magnetic resonance image scan is a better modality.

• Coupled systems mechanics
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• 제11권1호
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• pp.15-32
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• 2022

The comprehensive understanding of the fiber reinforced polymer behavior requires the use of advanced non-destructive testing methods due to its heterogeneous microstructure and anisotropic mechanical proprieties. In addition, the material response under load is strongly associated with manufacturing defects (e.g., voids, inclusions, fiber misalignment, debonds, improper cure and delamination). Such imperfections and microstructures induce various damage mechanisms arising at different scales before macrocracks are formed. The origin of damage phenomena can only be fully understood with the access to underlying microstructural features. This makes X-ray Computed Tomography an appropriate imaging tool to capture changes in the bulk of fibrous materials. Moreover, Digital Volume Correlation (DVC) can be used to measure kinematic fields induced by various loading histories. The correlation technique relies on image contrast induced by microstructures. Fibrous composites can be reinforced by different fiber architectures that may lead to poor natural contrast. Hence, a priori analyses need to be performed to assess the corresponding DVC measurement uncertainties. This study aimed to evaluate measurement resolutions of global and regularized DVC for glass fiber reinforced polymers with different fiber architectures. The measurement uncertainties were evaluated with respect to element size and regularization lengths. Even though FE-based DVC could not reach the recommended displacement uncertainty with low spatial resolution, regularized DVC enabled for the use of fine meshes when applying appropriate regularization.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2854-2863
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• 2023

Objective: To present a hybrid approach that incorporates a constrained beam-hardening estimator (CBHE) and deep learning (DL)-based post-refinement for metal artifact reduction in dental cone-beam computed tomography (CBCT). Methods: Constrained beam-hardening estimator (CBHE) is derived from a polychromatic X-ray attenuation model with respect to X-ray transmission length, which calculates associated parameters numerically. Deep-learning-based post-refinement with an artifact disentanglement network (ADN) is performed to mitigate the remaining dark shading regions around a metal. Artifact disentanglement network (ADN) supports an unsupervised learning approach, in which no paired CBCT images are required. The network consists of an encoder that separates artifacts and content and a decoder for the content. Additionally, ADN with data normalization replaces metal regions with values from bone or soft tissue regions. Finally, the metal regions obtained from the CBHE are blended into reconstructed images. The proposed approach is systematically assessed using a dental phantom with two types of metal objects for qualitative and quantitative comparisons. Results: The proposed hybrid scheme provides improved image quality in areas surrounding the metal while preserving native structures. Conclusion: This study may significantly improve the detection of areas of interest in many dentomaxillofacial applications.

• 대한치과교정학회지
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• 제48권5호
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• pp.346-346
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• 2018

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
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• pp.177-180
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• 2000

CT images are sequential images that provide medical doctors helpful information for treatment and surgical operation. It is also widely used for the 3D reconstruction of human bone and organs. In the 3D reconstruction, the quality of the reconstructed 3D model heavily depends on the segmentation results. In this paper, we propose an algorithm suitable for the segmentation of teeth and the maxilofacial bone.

• Tuberculosis and Respiratory Diseases
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• 제57권6호
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• pp.515-521
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• 2004

With the increasing resolution of modern CT scanners, analysis of the larger numbers of images acquired in a lung screening exam or diagnostic study is necessary, which also needs high accuracy and reproducibility. Recent developments in the computerized analysis of medical images are expected to aid radiologists and other healthcare professional in various diagnostic tasks of medical image interpretation. This article is to provide a brief overview of some of computer-aided diagnosis schemes in chest CT.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 1999년도 Japanese Journal of Medical Physics
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• pp.266-267
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• 1999

• 대한방사선과학회:학술대회논문집
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• 대한방사선과학회 2005년도 춘계학술대회
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• pp.154-155
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• 2005