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Article type: Cover
1992 Volume 48 Issue 6 Pages
Cover17-
Published: June 01, 1992
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Article type: Index
1992 Volume 48 Issue 6 Pages
Toc17-
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Article type: Index
1992 Volume 48 Issue 6 Pages
Toc18-
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Article type: Appendix
1992 Volume 48 Issue 6 Pages
i-v
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Article type: Appendix
1992 Volume 48 Issue 6 Pages
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YOSHIHARU SAKASHITA, HIROKI OGURA, YOSHITAKA OONISHI
Article type: Article
1992 Volume 48 Issue 6 Pages
852-859
Published: June 01, 1992
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Aggravation of the reconstructed images on CT scans by motion artifacts is one of the most serious problems in radiological diagnosis. For the analysis of the motion artifacts, a motion analysing phantom for CTs, which rotates at a constant speed in the scanning field, was developed. We investigated the following subjects using the phantom. First, the degree the CT scanner is affected by biological motions, such as respiratory or intestinal motions was investigated. Next, an attempt to construct a drawing of the back projection to explain the motion artifacts by rotational movement of objects theoretically was carryed. The X-ray CT images that were made by the phantom experiments and clinical studies show a good correlation. Drawing diagram was simple and convincing methods to explain the motion artifacts were achieved. Other types of CT scanners were produced similar artifacts. Therefore, we concluded that every type of CT scanners can have similar artifacts under the same conditions. Research of the patterns of motion artifacts will become more important for diagnosing and image processing, when CT scanner technology can scan faster.
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FUMIAKI UTO, AKIKO SHIRAI, YOSHIHIKO TSUJI, SHIGEKI UYAMA, KAZURO IWAT ...
Article type: Article
1992 Volume 48 Issue 6 Pages
860-866
Published: June 01, 1992
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Since the doses around sources in intracavitary radiation therapy changed rapidly with distance from sources, measurment of the dose distribution is very difficult. A thermoluminescence [TL] sheet and its spatial readout system used measurement of cosmicrays has been applied for dosimetry of the intracavitary radiation therapy. The TL sheet, which is composed of tefron mixed with BaSO_4 : Eu powder, has a linear response with a very wide dynamicrange from at least 0.002 cGy to 5000 cGy for ^<60>Co-γ rays. In this study, the characteristics of annealing, measurement of the highdoserate distribution around ^<60>Co sources and the method for measuring the dose distribution using TL emission at the normal temperature (25℃) were shown. The TL sheet was suggested to provide a convenient means of measuring the dose distribution around sources in intracavitary radiation therapy.
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HIROFUMI MARUISHI, TADASHI SUNAYASHIKI, MINORU FUJITA, YOSHIE KODERA, ...
Article type: Article
1992 Volume 48 Issue 6 Pages
867-874
Published: June 01, 1992
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Electronic unequilibrium status before and after lead shields in water with use of ^<60>Co γ-ray, 4 and 10 MV X-ray beams was studied both experimentally and with the Monte Carlo caluculation. A marked increase regarding relative doses was observed 2 to 10 mm before the lead shields. Characteristic fractuations of relative doses were calculated in the area of 5 to 20 mm after the lead shields with a dependence of each photon energy. Three to five percent of the dose reduction effect per 1 mm thickness of lead was also calculated in the area of the electronic equilibrium, enough backward after lead shields. Such electronic unequilibrium status is produced by the difference of both the magnitude of initial energy and the quantity of secondary electrons, and also by the difference of stopping power between the water and lead against any secondary electrons. Due to our study, details of such status were revealed with use of the Monte Carlo calculation.
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OSAMU WAKAMATSU, YOSHIO IMAI, MASATOSHI KOBAYASHI
Article type: Article
1992 Volume 48 Issue 6 Pages
875-879
Published: June 01, 1992
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Modulation transfer function (MTF) values in visual perception of various radiographic images by contrast medium charts were computed. The magnitude estimation method was adopted and applied opthalmologic contrast sensitivity to assess spatial MTF. This experiment showed maximum peak valus between the second and third cycles with changes according to the degree of the visual angle. It was concluded that this approach makes the calcuation easier because it needs only two measurements of physical and visual contrast, and that it is one of the convenient methods for computing visual MTF.
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SHINYA UEDA, MASAMICHI SHIMAMURA, TAKEHIRO UCHIDA
Article type: Article
1992 Volume 48 Issue 6 Pages
880-884
Published: June 01, 1992
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The storage stability and graininess of the hypersensitized X-ray films by forming gas has been investigated. The hypersensitized and usual X-ray films, kept at room temperature, were compared according to variations in speed, average gradient and fog. No variations in average gradient and Wiener spectrum (D=1.0), but some series of the hypersensitized X-ray films had lowering speed and a slight rising fog were observed. The experimental results suggested that the hypersensitized X-ray films by forming gas could be useful for clinical diagnosis because moisture and oxygen hardly influence their 30 day storage.
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YOSHIHARU HIRATA, TOMOMASA YAMAGUCHI, TAKEFUMI YAMANE, HIROYUKI FUJIHA ...
Article type: Article
1992 Volume 48 Issue 6 Pages
885-892
Published: June 01, 1992
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The introduction of PACS developed in our department of radiology and evaluation of the system were made. As a result, the following could be observed. 1) Image transfer by PACS proved to be more precise than either man or airshooter ; capable of saving power as well as time. 2) A great deal of time and manpower for the image examination could be saved. 3) Although communication now has to be faster, it is thought that the software will make up for this. 4) Many points were noted in the image-inputting system. 5) CRT reading was fully possible, dependent on the image processing method. In conclusion, PACS has numerous merits such as saving in power, time and space in image transfer, keeping as well as many others. However, image reading and calling have many problems in terms of both software and hardwares, making it necessary for both radiologists and radiological technologist to cooperate in preparing spot-matched images.
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MITSUHIRO MATSUMOTO, TOSHIKUNI KIKUCHI, SINYA ITO, YASUMITSU KAWAGOE, ...
Article type: Article
1992 Volume 48 Issue 6 Pages
893-899
Published: June 01, 1992
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Carcinoma of the maxillary sinus extends into various directions according to the individual. One standard dose distribution cannot satisfy each patient when extended into various directions. A study was made and sub-standard dose distribution patterns were obtained for each direction of the extension, using a radiotherapy planning computer (MODULEX) and ^<60>Co gamma-ray data. Extension modes were classified into 8 types. In cases for the standard type, we used 2 evenly weighted wedge-paired portals, one : AP and another : lateral oblique, with a set depth of 4.5cm. Portal width : 8cm in AP and 8cm in lateral oblique. Cross angle of the beams : 75°, Degree of the wedge filters : 45°each. The eye balls and brain were shielded as much as possible. Planning patterns differed according to various types of extension. These patterns were used for each patient at the beginning of the radiotherapy, with the information of extension direction but without obtaining planning CT, or computer processing.
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
900-910
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Article type: Bibliography
1992 Volume 48 Issue 6 Pages
910-
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[in Japanese], [in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
911-913
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
914-917
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
917-919
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[in Japanese], [in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
919-921
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
921-924
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
925-936
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Article type: Appendix
1992 Volume 48 Issue 6 Pages
937-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
937-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
937-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
937-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
937-
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Article type: Article
1992 Volume 48 Issue 6 Pages
937-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
937-938
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Article type: Appendix
1992 Volume 48 Issue 6 Pages
938-
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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Article type: Article
1992 Volume 48 Issue 6 Pages
938-
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Article type: Article
1992 Volume 48 Issue 6 Pages
938-939
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Article type: Article
1992 Volume 48 Issue 6 Pages
939-
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Article type: Article
1992 Volume 48 Issue 6 Pages
939-
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Article type: Article
1992 Volume 48 Issue 6 Pages
939-
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Article type: Article
1992 Volume 48 Issue 6 Pages
939-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
939-
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Article type: Article
1992 Volume 48 Issue 6 Pages
939-940
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[in Japanese]
Article type: Article
1992 Volume 48 Issue 6 Pages
940-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
940-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
940-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
940-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
940-941
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Article type: Article
1992 Volume 48 Issue 6 Pages
941-
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Article type: Article
1992 Volume 48 Issue 6 Pages
941-
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Article type: Article
1992 Volume 48 Issue 6 Pages
941-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1992 Volume 48 Issue 6 Pages
941-
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