• Title/Summary/Keyword: Computed Tomography X-Ray

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Yarn Segmentation from 3-D Voxel Data for Analysis of Textile Fabric Structure

  • Shinohara, Toshihiro;Takayama, Jun-ya;Ohyama, Shinji;Kobayashi, Akira
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.877-881
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    • 2005
  • In this paper, a novel method for analyzing a textile fabric structure is proposed to segment each yarn of the textile fabric from voxel data made out of its X-ray computed tomography (CT) images. In order to segment the each yarn, directions of fibers, of which yarn consists, are firstly estimated by correlating the voxel with a fiber model. Second, each fiber is reconstructed by clustering the voxel of the fiber using the estimated fiber direction as a similarity. Then, each yarn is reconstructed by clustering the reconstructed fibers using a distance which is newly defined as a dissimilarity. Consequently, each yarn of the textile fabric is segmented from the voxel data. The effectiveness of the proposed method is confirmed by experimentally applying the method to voxel data of a sample plain woven fabric, which is made of polyester two folded yarn. The each two folded yarn is correctly segmented by the proposed method.

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Characterization of Burned Architectural Woods by Fire Using SEM-EDXS and Computerized Tomography

  • Lee, Hyun-Mi;Hwang, Won-Joung;Lee, Dong-Heub;Son, Dong-Won
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.5
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    • pp.516-522
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    • 2014
  • Old architectural wood materials damaged by a fire were evaluated on the basis of wood species and scanning electron microscopy (SEM) observation of wood tissues in combination with energy dispersive X-ray spectroscopy (EDXS) analysis. Results of SEM observation showed that tracheid wall thickness of burned parts was very thin compared with undamaged and sound wood, and tylosoid in the resin canals disappeared after the exposure to fire. SEM-EDXS analysis indicated that carbon and oxygen peaks occurred in the original energy band, and the carbon peak was higher than that of the oxygen in the burned part. A computerized tomography was also undertaken to investigate the carbonization layer formed by fire and possible internal defects.

Comparison of cone beam CT and conventional CT in absorbed and effective dose (Cone beam CT와 일반 CT의 흡수선량 및 유효선량 비교평가)

  • Kim, Sang-Yeon;Han, Jin-Woo;Park, In-Woo
    • Imaging Science in Dentistry
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    • v.38 no.1
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    • pp.7-15
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    • 2008
  • Purpose: This study provides comparative measurements of absorbed and effective doses for newly developed cone beam computed tomography (CT) in comparison with these doses for conventional CT. Materials and Methods: Thermoluminescent dosimeter rods (TLD rod: GR-200, Thermo Fisher Scientific Inc., Waltham, MA, USA) were placed at 25 sites throughout the layers of Male ART Head and Neck Phantom (Radiology Support Devices Inc., Long Beach, USA) for dosimetry. Implagraphy, DCT Pro (Vatech Co., Hwasung, Korea) units, SCT-6800TXL (Shimadzu Corp., Kyoto, Japan), and Crane x 3+(Soredex Orion Corp., Helsinki, Finland) were used for radiation exposures. Absorption doses were measured with Harshaw 3500TLD reader (Thermo Fisher Scientific Inc., Waltham, MA, USA). Radiation weighted doses and effective doses were measured and calculated by 2005 ICRP tissue weighting factors. Results: Absorbed doses in Rt. submandibular gland were 110.57 mGy for SCT 6800TXL (Implant), 24.56 mGy for SCT 6800TXL (3D), 22.39 mGy for Implagraphy 3, 7.19 mGy for DCT Pro, 5.96 mGy for Implagraphy 1, 0.70 mGy for Cranex 3+. Effective doses $(E_{2005draft)$ were 2.551 mSv for SCT 6800TXL (Implant), 1.272 mSv for SCT 6800TXL (3D), 0.598 mSv for Implagraphy 3, 0.428 mSv for DCT Pro and 0.146 mSv for Implagraphy 1. These are 108.6, 54.1, 25.5, 18.2 and 6.2 times greater than panoramic examination (Cranex 3+) doses (0.023mSv). Conclusion: Cone beam CT machines recently developed in Korea, showed lower effective doses than conventional CT. Cone beam CT provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

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Pulmonary Blastoma -A Case Report- (폐아세포종 -수술치험 1례-)

  • 금동윤
    • Journal of Chest Surgery
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    • v.27 no.10
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    • pp.868-873
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    • 1994
  • We experienced a very rare case of pulmonary blastoma in a 29 year old female. She complained of left chest pain and dyspnea for 1 month. The characteristic feature of this tumor is it`s biphasic pattern consisting of a spindle cell stroma containing glandular structures. A serial check of simple chest X-ray and computed tomography revealed a growing huge lung mass occupying whole left thorax. We successfully removed the upper lobe of left lung with a huge tumor mass. Pathologic study revealed this tumor as pulmonary blastoma. We report a case with review of literature.

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Comparison of micro-computerized tomography and cone-beam computerized tomography in the detection of accessory canals in primary molars

  • Acar, Buket;Kamburoglu, Kivanc;Tatar, Ilkan;Arikan, Volkan;Celik, Hakan Hamdi;Yuksel, Selcen;Ozen, Tuncer
    • Imaging Science in Dentistry
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    • v.45 no.4
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    • pp.205-211
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    • 2015
  • Purpose: This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Materials and Methods: Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. Results: The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images. Conclusion: Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

A Case Report on the Patient of Malignant Melanoma at Right Maxilla with the Treatment of Bee Venom Phamacopuncture (봉독약침을 시행한 우측상악동의 악성 흑색종 환자에 대한 증례보고)

  • Bang, Sun-Hwi;Yoo, Hwa-Seung
    • Journal of Pharmacopuncture
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    • v.10 no.2 s.23
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    • pp.99-105
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    • 2007
  • Objectives : It is the aim of this study to derive lurker studies evaluating the effectiveness of bee-venom phamacopuncture on malignant melanoma patients. We present a patient of malignant melanoma at right maxilla who survives over one year with stable disease (SD) by the treatment of Bee Venom Phamacopuncture (BVP). Methods : We followed the treatment and examination. We prescribed to the patient what to be taken 1.5cc BVP once a day. Picture series, Head series were followed-up and Neck computed tomography (CT) and positron emission tomography computed tomography (PET CT) were performed to evaluate the therapeutic efficacy. Results : The patient survives over one year and continued stable disease over 6 months. Picture series, Head series X-ray, neck CT and PET CT were shown no interval change. Conclusion : This case may give us the possibility that BVP offers potential benefits for patients with malignant melanoma.

Requirements for Future Digital Radiology System

  • Kim, Y.M.;Park, H.W.;Haynor, D.R.
    • Progress in Medical Physics
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    • v.2 no.1
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    • pp.3-16
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    • 1991
  • Abstract. An area of particularly rapid technological growth in the last 15 years has been medical imaging (conventional X-ray, ultrasound, X-ray computed tomography (CT), magnetic resonance imaging (MRI). As the number and complexity of imaging studies rises, it becomes ever more important to distribute these images and the associated diagnoses in a timely and cost-effective fashion. The purpose of this paper is to describe the requirements for a future digital radiology system which will efficiently handle the large volume of images that generated, add new functionality to improve productivity of physicians, technologists, and other health care providers, and provide enough flexibility to allow the system to grow as medical image technology grows.

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Image Quality Improvement in Computed Tomography by Using Anisotropic 2-Dimensional Diffusion Based Filter (비등방성 2차원 확산 기반 필터를 이용한 전산화단층영상 품질 개선)

  • Seoung, Youl-Hun
    • Journal of the Korean Society of Radiology
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    • v.10 no.1
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    • pp.45-51
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    • 2016
  • The purpose of this study was tried to remove the noise and improve the spatial resolution in the computed tomography (CT) by using anisotropic 2-dimensional (2D) diffusion based filter. We used 4-channel multi-detector CT and american association of physicists in medicine (AAPM) phantom was used for CT performance evaluation to evaluate the image quality. X-ray irradiation conditions for image acquisition was fixed at 120 kVp, 100 mAs and scanned 10 mm axis with ultra-high resolution. The improvement of anisotropic 2D diffusion filtering that we suggested firstly, increase the contrast of the image by using histogram stretching to the original image for 0.4%, and multiplying the individual pixels by 1.2 weight value, and applying the anisotropic diffusion filtering. As a result, we could distinguished five holes until 0.75 mm in the original image but, five holes until 0.40 mm in the image with improved anisotropic diffusion filter. The noise of the original image was 46.0, the noise of the image with improved anisotropic 2D diffusion filter was decreased to 33.5(27.2%). In conclusion improved anisotropic 2D diffusion filter that we proposed could remove the noise of the CT image and improve the spatial resolution.

Evaluation of Pore Size Distribution of Berea Sandstone using X-ray Computed Tomography (X-ray CT를 이용한 베레아 사암의 공극크기분포 산정)

  • Kim, Kwang Yeom;Kim, Kyeongmin
    • The Journal of Engineering Geology
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    • v.24 no.3
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    • pp.353-362
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    • 2014
  • Pore structures in porous rock play an important role in hydraulic & mechanical behaviour of rock. Porosity, size distribution and orientation of pores represent the characteristics of pore structures of porous rock. While effective porosity can be measured easily by conventional experiment, pore size distribution is hard to be quantified due to the lack of corresponding experiment. We assessed pore size distribution of Berea sandstone using X-ray CT image based analysis combined with associated images processing, i.e., image filtering, binarization and skeletonization subsequently followed by the assessment of local thickness and star chord length. The aim of this study is to propose a new and effective way to evaluate pore structures of porous rock using X-ray CT based analysis for pore size distribution.

Dynamically Collimated CT Scan and Image Reconstruction of Convex Region-of-Interest (동적 시준을 이용한 CT 촬영과 볼록한 관심영역의 영상재구성)

  • Jin, Seung Oh;Kwon, Oh-Kyong
    • Journal of Biomedical Engineering Research
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    • v.35 no.5
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    • pp.151-159
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    • 2014
  • Computed tomography (CT) is one of the most widely used medical imaging modality. However, substantial x-ray dose exposed to the human subject during the CT scan is a great concern. Region-of-interest (ROI) CT is considered to be a possible solution for its potential to reduce the x-ray dose to the human subject. In most of ROI-CT scans, the ROI is set to a circular shape whose diameter is often considerably smaller than the full field-of-view (FOV). However, an arbitrarily shaped ROI is very desirable to reduce the x-ray dose more than the circularly shaped ROI can do. We propose a new method to make a non-circular convex-shaped ROI along with the image reconstruction method. To make a ROI with an arbitrary convex shape, dynamic collimations are necessary to minimize the x-ray dose at each angle of view. In addition to the dynamic collimation, we get the ROI projection data with slightly lower sampling rate in the view direction to further reduce the x-ray dose. We reconstruct images from the ROI projection data in the compressed sensing (CS) framework assisted by the exterior projection data acquired from the pilot scan to set the ROI. To validate the proposed method, we used the experimental micro-CT projection data after truncating them to simulate the dynamic collimation. The reconstructed ROI images showed little errors as compared to the images reconstructed from the full-FOV scan data as well as little artifacts inside the ROI. We expect the proposed method can significantly reduce the x-ray dose in CT scans if the dynamic collimation is realized in real CT machines.