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原稿種別: 表紙
1990 年 46 巻 1 号 p.
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発行日: 1990/01/01
公開日: 2017/06/29
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原稿種別: 目次
1990 年 46 巻 1 号 p.
Toc1-
発行日: 1990/01/01
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原稿種別: 目次
1990 年 46 巻 1 号 p.
Toc2-
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
i-viii
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
ix-xiii
発行日: 1990/01/01
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小川 正晃, 砂屋敷 忠, 山根 由美子, 小寺 吉衛, 和田 卓郎
原稿種別: 本文
1990 年 46 巻 1 号 p.
1-6
発行日: 1990/01/01
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Some types of filters to eliminate the grid pattern from a radiograph which was taken with an antiscatter grid were proposed. By visual evaluation, the acceptability of processed images was estimated. It was concluded that these filtering methods were effective in eliminating the grid pattern without reduction in image quality.
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宮越 敬三, 宇佐美 公男, 佐藤 孝司
原稿種別: 本文
1990 年 46 巻 1 号 p.
7-13
発行日: 1990/01/01
公開日: 2017/06/29
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It is known that the image contrast of radiography has been changed due to intensify screen of medical radiography. In this study, X-ray absorption energy of some intensifying phosphors (CaWO_4, Y_2O_2S : Tb, BaSO_4 : Eu, Gd_2O_2S : Tb) which transfer to light energy was calculated using the Monte Calro simulation for transmitted X-ray through a water phantom on incident various X-ray energy. As a result, the relative absorption energy in phosphors was changed by the energy absorption coefficients (ie. atomic number) of phosphors. Also, the lineality for absorption energy and the water phantom thickness was affected by the change in shape of X-ray spectra when transmitted from the phantom.
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中田 学, 西台 武弘, 野原 弘基, 岡田 孝, 矢野 慎輔, 上総 中童, 吉永 容子, 永田 靖, 阿部 光幸
原稿種別: 本文
1990 年 46 巻 1 号 p.
14-21
発行日: 1990/01/01
公開日: 2017/06/29
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A new three-dimensional (3-D) computation algorithm, "Modified equivalent TMR method", for photon beam dose calculation considering the heterogeneous correction has been developed. This algorithm in based on the modified equivalent TAR method that was proposed by Inamura et al. The modified equivalent TMR method has two calculation modes; the scatter mode which takes account for the 3-D contribution of scattered radiation and the non-scatter mode which doesn't. The dose distributions on off-central axis can be obtained from a approximate expression using the penumbra factor suggested by Shribastava and Cunningham. The purpose of this study is to evaluate the accuracy of dose computations using of this new algorithm. The accuracy is compared with both calculations and measurements on off-central axis for Cobalt-60 gamma rays and 10MV photon beams for various geometries and field sizes. Using the modified equivalent TMR method, we could show that the accuracy of 3-D dose computation on off-central axis with the scatter mode in unit-density phantom agreed with measured the data within 6%. For rectangular and irregular fields, this algorithm based on the scatter mode is accurate to a satisfactory lenel, while calculations on the off-central axis within the low density medium used two algorithm are inadequate in situation of electron disequilibrium, in particular near the beam edge. To satisfy the routine clinical needs of radiation therapy, it is highly desirable to develop a satisfactory approximation to situation of electron disequilibrium. In particular with present-day computers, it may take days of computation to obtain an accurate dose distribution in a single inhomogeneous medium. For new calculating algorithm that we have been developed, it may be applied with a suitable accuracy and reasonable computation time except for the electron disequilibrium regions.
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石田 隆行, 山下 一也, 滝川 厚
原稿種別: 本文
1990 年 46 巻 1 号 p.
22-28
発行日: 1990/01/01
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The image that has been scanned to produce an analog signal which is then converted into digital form and stored in the frame memory, by means of a small scale image processing system. This time, the physical charactristics in these digitized images were extracted from the image analysis. The image processing system is comparatively low in price and very avaliable, and is able to be applied image analysis, various processing of digitized images. Sensitometric strips and slit images were made in the same way as the conventional method. These samples were scanned using a CCD camera; not using a microdensitometer. The modulation transfer factors (MTF's) of screen/film system was calculated by the Fourier transform method, by means of the digitized image data. There were hardly any difference between MTF that had been measured for the conventional system by means of microdensitometer and that which had been measured for our digital image processing system. This measurement method have several merits when compaed with the conventional method; The measurement time required was greatly shorten, and various influences were excluded which are nopmoely caused by a microdensitometer.
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白石 順二, 津田 和良
原稿種別: 本文
1990 年 46 巻 1 号 p.
29-34
発行日: 1990/01/01
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CT装置のスライス厚の測定は傾斜法がもっとも一般的であり, 本施設においても通常の測定においてはおもにこの方法を用いている.また, 実際の臨床使用において1mm以下の誤差は, ほとんどの場合, 診断に影響がなく, 今回計測されたような精度の測定値の必要性には問題がある.しかし, 傾斜法が日常のチェックには至適であっても, 薄いスライス厚などにはその精度に疑問点があることは事実である.そのため, メーカーのサービスの調整に一任した形ではなく, 本当のスライス厚について確信の持てる測定法として, 今回Partial volume effectを用いた測定法を考案した.本法は専用のファントムを使用するために, 一般的とは言えないが, その理論を用いて実験を行うことは比較的簡便であり, その測定精度も良いと考える.以上から, 本法はCTのスライス厚の測定の方法としては非常に有用な方法であると考える.
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小田 敍弘, 平松 理光, 小川 治久, 中野 努, 中野 秀一朗
原稿種別: 本文
1990 年 46 巻 1 号 p.
35-39
発行日: 1990/01/01
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Immobilizing pad suppressing motion artifact in abdominal intravenous digital subtraction angiography (IVDSA). A new device suppressing motion artifact in abdominal intravenous digital subtraction angiography (IVDSA) was made. It consists of a styrol foam pad and magic fastener bands. The styrol foam pad is fastened tightly to press the patient's upper abdominal portion by the bands. This device not only minimizes the motion artifact but improves image quality by decreasing the subject thickness.
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五島 仁士
原稿種別: 本文
1990 年 46 巻 1 号 p.
40-44
発行日: 1990/01/01
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Among many different factors affecting MR image qualities, scanning parameters including spatial, density and temporal resolutions, in particular, should be controlled principally by the operator. This paper presents measures to improve the author's study focuses on the MRI phantom for which we examine the four physical parameters ρ, T_1, T_2, and Q. The author elucidates that the prerequisite imposed on the MRI-phantom is that every parameter cited should be, without exception. equivalent to that of the living tissue. The PVA gel is presented below as an elementary material that meets our requirement.
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沢田 武司
原稿種別: 本文
1990 年 46 巻 1 号 p.
45-52
発行日: 1990/01/01
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Some technical problems concerning the MRI were studied, on the basis of 20 months' experiences with 1, 500 patients, using the apparatus of Shimazu SMT-150 (1.5T). This report contained such problems as follows : 1. Space leakage of magnetic fields was surveyed, and the methods of maintenance of the apparatus was discussed. 2. Slice thickness of MRI was measured and compared with that of CT. 3. T_1 and T_2 relaxation time was measured using diluted Gd-DTPA solution. 4. In respect of susceptibility artifacts of MRI, an investigation was performed. 5. Some other technical trials and attempt were presented.
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槙田 淳一
原稿種別: 本文
1990 年 46 巻 1 号 p.
53-56
発行日: 1990/01/01
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以上実用的な3DFT法を中心に, またその他の表示法も検討した.MRIの開発研究は今後ますます進んで, エコープラナによる超高速スキャンにと移って行く事であろう.より臨床的に有用で, 実用的な画像表示法を今後も考えていきたい.
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滝沢 修
原稿種別: 本文
1990 年 46 巻 1 号 p.
57-62
発行日: 1990/01/01
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The MRI technique is now introduced in the clinical sites as a clinical diagnostic modality. As the NMR technique itself, it is still incomplete and is rapidly developping. In this paper, the problems of the presently existing MR technique are discussed especialy for the long examination time, moving artifact and the S/N ratio for the thin slice imaging. Based on these problems. the technique which is now going to be introduced in the clinical examination are explained. For the implimentation of these techniques and for the best use of them it is strongly required to accumulate the experiences and the deep technical considerations. These include fast scan imaging, the motion artefact suppression, 3D volume scan and MR angiography. In the lase part of the paper, we discuss the field where MR can take part in for the future clinical Medicine, which may include the fast imaging and the tissue characterization such like organ function analysis.
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川口 博巳
原稿種別: 本文
1990 年 46 巻 1 号 p.
63-67
発行日: 1990/01/01
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Recently the tequnologies of MRI and MRS had been advanced so brilliantly. On the view point of the method of imaging reconstruction almost every systems use Fourier Zeugmatography method. But they still have independent characteristics. This thesis gives some interpretation to these characteristics.
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真野 勇
原稿種別: 本文
1990 年 46 巻 1 号 p.
68-
発行日: 1990/01/01
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山下 一也, 斎藤 一彦, 佐藤 伸雄, 原田 昭夫, 増田 和浩, 川崎 雄一, 佐藤 龍一郎, 久保田 正男, 鈴木 操, 野里 英運, ...
原稿種別: 本文
1990 年 46 巻 1 号 p.
69-71
発行日: 1990/01/01
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川末 健作, 相沢 昭二, 松田 幸広, 宮前 悦子, 上野 哲雄, 雨宮 信司, 牛尾 健, 新木 操, 北川 松雄, 花井 耕造, 周東 ...
原稿種別: 本文
1990 年 46 巻 1 号 p.
72-73
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
74-78
発行日: 1990/01/01
公開日: 2017/06/29
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
80-81
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
82-89
発行日: 1990/01/01
公開日: 2017/06/29
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
90-95
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
96-114
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
114-
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
114-
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
115-
発行日: 1990/01/01
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原稿種別: 付録等
1990 年 46 巻 1 号 p.
116-
発行日: 1990/01/01
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原稿種別: 表紙
1990 年 46 巻 1 号 p.
Cover2-
発行日: 1990/01/01
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