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Volume 20 (2003)
- Issue 3 Pages 138-
- Issue 2 Pages 82-
- Issue 1 Pages 9-
Volume 20, Issue 3
Displaying 1-5 of 5 articles from this issue
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Ryugo KIJIMA2003 Volume 20 Issue 3 Pages 138-143
Published: 2003
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSIn this article, the application of Virtual Reality is discussed. The author is trying to map the image on the real object in order to show the internal structure using Projection Head Mounted Display (PHMD) and several example applications of this approach in the field of medical training are shown in this paper. Finally a preliminary result of the training simulator for the emergency situation is discussed.View full abstractDownload PDF (6552K) -
Yoshinori OCHIAI, Roman JANER2003 Volume 20 Issue 3 Pages 144-153
Published: 2003
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSDownload PDF (12632K) -
Eiichi SATO, Yasuomi HAYASI, Rudolf GERMER, Etsuro TANAKA, Hidezo MORI ...2003 Volume 20 Issue 3 Pages 154-161
Published: 2003
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSIn the plasma flash x-ray generator, a high-voltage main condenser of approximately 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod target by electric field in the x-ray tube, the weakly ionized linear plasma, which consists of molybdenum ions and electrons, forms by target evaporation. At a charging voltage of 50 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, the linear plasma formed, and the K -series characteristic x-ray intensities increased. The K lines were quite sharp and intense, and hardly any bremsstrahlung rays were detected. When a copper target was employed, the x-ray pulse widths were appmximtely 700 ns, and the time-integrated x-ray intensity had a value approximately 30μ C/kg at 1.0 m from the x-ray source with a charging voltage of 50 kV.View full abstractDownload PDF (4548K) -
Shinji SASAKI, Shoji KIDO, Hideyuki IWANAGA2003 Volume 20 Issue 3 Pages 162-169
Published: 2003
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSTo eliminate rib opacities on chest radiographs for quantitative evaluation of diffuse lung opacities, we developed an automated segmentation algorithm of rib opacities on chest radiographs. In the first step, a region of interest (ROI) was selected on chest radiographs, and unsharp mask filtering was performed for background density correction. In the next step, a Laplacian-Gaussian filter was used for the enhancement of rib opacities; next, the image was binarized on the ROI with a multiple-threshold method; and then a morphological filter was used for elimination of noise components. A parallel translation algorithm, Hough transformation, and polynomial approximation were used for estimation of the smooth contours of rib opacities. Finally, the rib opacities on the original ROI were determined by use of these estimated rib opacities as templates.View full abstractDownload PDF (9084K) -
Norio Hayashi, Shigeru Sanada, Masayuki Suzuki, Yukihiro Matsuura2003 Volume 20 Issue 3 Pages 170-175
Published: 2003
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSMR imaging is a very important method for the diagnosis of intracranial lesions. A measurement of the volume of the temporal lobe is a very useful method in diagnosing temporal lobe abnormalities. Therefore we develop the algorithm of the automated volumetry of the temporal lobe. However, it is often difficult to segment the temporal lobe. The Sylvian fissure is an important index for the segmentation of the temporal lobe. The purpose of this study is to develop the algorithm of the automated identification of the Sylvian fissure. We studied 10 normal volunteers and 2 patients who were suspected of Alzheimer disease. We performed the following four steps: (1) Segmentation of the brain on coronal images. (2) Edge enhancement of the y-direction on sagittal images. (3) Hough transform on edge-enhanced images. (4) Correction of R-L direction and S-I direction. In results, this method proved to be able to identify the Sylvian fissure on coronal and sagittal MR images in normal volunteers and patients. It is concluded that the Sylvian fissure identified by this method is a very useful index of the segmentation of the temporal lobe.View full abstractDownload PDF (5752K)
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