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Article type: Cover
1993 Volume 49 Issue 12 Pages
Cover7-
Published: December 01, 1993
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Article type: Index
1993 Volume 49 Issue 12 Pages
Toc7-
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Article type: Index
1993 Volume 49 Issue 12 Pages
Toc8-
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
i-iv
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TOSHIYUKI AOI, MICHIHIRO YAMAGUCHI, YOSHIYUKI ASAI, HIDEYO MORI
Article type: Article
1993 Volume 49 Issue 12 Pages
1984-1991
Published: December 01, 1993
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No reports exist to describe the factors of color and time in evaluating diagnostic images. We studied the visual characteristics concerning time factors. Namely, changes in visual acuity and visual fatigue were studied according to various kinds of light sources. Visual acuity was kept during the longest time when using yellow and green light sources. On the other hand, visual acuity decreased gradually when using a blue light source. Regarding visual fatigue, green was the best light source. From the ROC curves in the visual evaluation of images, yellow and green were the best light source, with blue being the worst. The most suitable wavelength was between 535 and 620 nm for every color concerning discriminations of density and luminance. The best wavelength discrimination was between 490 and 600 nm. These results were in good agreement with those of visual acuity, visual fatigue and the ROC curves.
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KIYOSHI OGURO, SUGURU KOTAKI, SHUSAKU HARADA, YOSHIMITSU MTSUMURA, TOS ...
Article type: Article
1993 Volume 49 Issue 12 Pages
1992-1998
Published: December 01, 1993
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Short SE, STIR and the chemical shift sequence by Dixon were compared for their ability to observed the tethered cord in 13 patients. For the short SE sequence, the cord was obscured because of the high signal of lipoma, and for STIR sequence, the contrast between the cord and CSF was not enough. On the other hand, the water image of the chemical shift seqence with short TR suppressed the signal of both CSF and lipoma, and the tethered cord could be clearly observed. We concluded that the chemical shift seqence is the first choice for evaluating the tethered cord syndrome.
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FUJIO ARAKI, KOZO KUMAGAI, TAKUMI ISERI, TAKESHI KAWANO
Article type: Article
1993 Volume 49 Issue 12 Pages
1999-2006
Published: December 01, 1993
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Recently, total body irradiation (TBI) is being used as a method of preparation for bone marrow transplantation (BMT). However, many variations exist in the TBI procedure, such as the irradiation technique, total dose, dose rate and dose fractionation. In TBI treatment, it is important to apply a homogeneous dose to the total body, and avoid interstitial pneumonitis and cataracta. Therefore, we applied a four-field technique using 10 MV X-rays with a shield for lungs and eyeballs, and employed tissue compensators and bolus to obtain a homogeneous dose distribution. The midpoint doses in 12 positions of the total body have been achieved within±10% of that of the pelvis with the use of this technique. Also, this TBI technique is capable of accurately controlling absorbed doses to the lungs and eyes.
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TAKAO MUKAI
Article type: Article
1993 Volume 49 Issue 12 Pages
2007-2021
Published: December 01, 1993
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AKIYOSHI OHTSUKA
Article type: Article
1993 Volume 49 Issue 12 Pages
2022-2023
Published: December 01, 1993
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YOSHIHARU HIGASHIDA
Article type: Article
1993 Volume 49 Issue 12 Pages
2024-2029
Published: December 01, 1993
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This paper deals with the optimum radiographic condition in digital radiographic systems. Radiographic conditions for chest and bone radiography with the computed radiographic (CR) system were reviewed. The effect of incident exposure on the detectability of various abnormalities including nodule, pneumothorax, asbestosis, fine pulmonary line and other abnormalities were also discussed. Radiographic conditions for radiography with portable X-ray unit and CR system were investigated at several institutions. Chest and abdominal examinations with the CR system were performed under the same exposure conditions as those of screen-film systems. However, large fluctuations in the radiographic condition were found by some technologists.
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MASAMITSU ISHIDA
Article type: Article
1993 Volume 49 Issue 12 Pages
2030-2036
Published: December 01, 1993
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The conventional screen/film system combines sensor, display and storage functions all together in one unit, which makes it difficult to optimize these functions separately. With the computed radiography (CR) system, on the other hand, these three functions are separated from each other into units, so that individual functions can be readily optimized by digital image processing techniques. The basic principle of CR system is to produce images optimized for various kind of diagnosis consistently. The image processing is performed to automatically normalize digital image data so that consistent image total density and contrast is always ensured irrespective of variations in X-ray dose and energy. The image processing optimized for each set of exposure menus is performed, i. e., gradation processing, frequency processing, and dynamic range control processing. Finally, the relationships between patient dose and the image quality of CR system are described.
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SADAMITSU NISHIHARA
Article type: Article
1993 Volume 49 Issue 12 Pages
2037-2043
Published: December 01, 1993
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When we discuss the relationship between patient dose and image quality, we often consider two methods, (1) Reduction of patient dose without decreasing image quality and (2) Increasing image quality without increasing patient dose. In this study, I discussed about the latter method, and proposed one guideline on how to improve on the detector in a computed radiographic (CR) system. A basic experiment and also two applied experiments were carried out to compare the two detectors (ST and HR) which have different image properties. As a result, the image quality of ST (high speed and low noise system) with image processing is higher than that of HR (low speed and high noise system) at the same incident dose to the detector and the image quality of ST with more removed scattered X-rays is superior than that of HR at the same patient dose. Therefore the improvement of the detector in the CR system requires higher speed and lower noise.
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KAZUHIRO MIHARA
Article type: Article
1993 Volume 49 Issue 12 Pages
2044-2051
Published: December 01, 1993
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The selection of exposure condition for the best Fuji computed radiographic (FCR) image is described. I have tried several kinds of experiments using the FCR system for finding the spatial resolution and contrast resolution in order to have an understanding of my viewpoint. The points of view for diciding the exposure condition of making radiographs using the FCR system are as follows : 1) The image quality needs to be treated as a function of dosage. 2) For making a diagnosis, the medical image needs to be compared with the superiority or inferiority under the same dosage condition. From the viewpoint of a reduction of patient dose I think it is important to decide the exposure condition in consideration of the projection region, diagnostic purpose, age of the patient etc... with complete clinical knowledge.
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TOSHIHIRO OGURA
Article type: Article
1993 Volume 49 Issue 12 Pages
2052-2057
Published: December 01, 1993
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We investigated imaging properties of a 2048×2048 matrix I.I./TV based digital radiography (DR) system (DR-2000 H) for various incident exposures. It should be noted that the resolution property of the I.I./TV based DR system depends on the incident exposures, the level of signal current from the TV image pickup tube and also regarding the size of the iris in the TV lens. Digital Wiener spectra and the detectabilities of low-contrast objects were measured for different incident exposures. It can be clearly seen that the noise properties and detectabilities decreased with a decrease in the incident exposures. The digital Wiener spectra also seemed to depend on the specific combination of the MTF's of the optical lenses, the level of signal current from the TV image pickup tube and quantum mottle. We must pay attention to these parameters when acquiring clinical images and evaluating the imaging properties. Furthermore, because the sensitivity of this system is higher than that of screen-film system, an X-ray tube of 0.2-mm focal spot is available routinely, the effect of geometric unsharpness can be reduced in practical clinical implementation ; the resolving power of the DR system with 7"-I.I. mode at a certain magnification factor are equivalent or even superior to the resolving power of screen-film system employed.
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AKIYOSHI OHTSUKA
Article type: Article
1993 Volume 49 Issue 12 Pages
2058-2060
Published: December 01, 1993
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TSUNEO MATSUMOTO
Article type: Article
1993 Volume 49 Issue 12 Pages
2061-2068
Published: December 01, 1993
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1993 Volume 49 Issue 12 Pages
2069-2078
Published: December 01, 1993
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[in Japanese], [in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2079-2080
Published: December 01, 1993
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[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2081-2084
Published: December 01, 1993
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[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2085-
Published: December 01, 1993
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[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2085-
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[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2085-
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[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2085-2086
Published: December 01, 1993
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Artificial Neural Networks in Mammography : Application to Decision Making in the Diagnosis of Breast Cancer, Yuzheng Wu, MSc Maryellen L. Giger, PhD Kunio Doi, PhD Carl J. Vyborny, MD, PhD Robert A. Schmidt, MD Charles E. Metz, PhD, Radiology 187, 81-87, (1993)
[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2086-
Published: December 01, 1993
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Characterisation of mammographic parenchymal pattern by fractal dimension, Curtis B Caldwell, Sandra J Stapleton, David W Holdsworth, Roberta A Jong, William J Weiser, Gabriel Cooke and Martin J Yaffe, Physics Medical Biology, 35, 235-247, (1990)
[in Japanese]
Article type: Article
1993 Volume 49 Issue 12 Pages
2086-
Published: December 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
2087-2093
Published: December 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
2094-2095
Published: December 01, 1993
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Article type: Index
1993 Volume 49 Issue 12 Pages
2096-2101
Published: December 01, 1993
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Article type: Index
1993 Volume 49 Issue 12 Pages
2102-2106
Published: December 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
2107-
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
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Article type: Appendix
1993 Volume 49 Issue 12 Pages
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Article type: Cover
1993 Volume 49 Issue 12 Pages
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Published: December 01, 1993
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