著者

阿部 宏 倉橋 正行 内田 勝 横山 三吉 畑川 政勝

出版者

Medical Imaging and Information Sciences

雑誌

放射線像研究 (ISSN:21870233)

巻号頁・発行日

vol.11, no.1, pp.11-15, 1981

著者

畑川 政勝 井上 誠 庄垣 雅史 岸本 健治 吉田 梨影

出版者

公益社団法人日本放射線技術学会

雑誌

日本放射線技術學會雜誌 (ISSN:03694305)

巻号頁・発行日

vol.48, no.11, pp.1932-1938, 1992-11-01

被引用文献数

13

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The modulation transfer function (MTF) has been used for evaluation of radiographic image quality. However, in digital radiographic system such as a computed radiography (CR), the MTF can not be used in the same way of an analog system for evaluation because digital system is not shift-invaliant system. Then, we suggest the "MTF_<final>" which includes geometric unsharpness, detector unsharpness, unsharpness of the sampling aperture and unsharpness of the display (Laser-printer). It is an analog component in the digital system and in agreement with the definition of the MTF. Furthermore, an overall aliasing has to be used with MTF_<final> for evaluating the digital system because it is one of the important factors of the digital system. The MTF_<final> and the overall aliasing can be obtained from the overall MTFs of the center alignment and the shifted alignment.

著者

白石 順二 山崎 勝 田中 克尚 岸本 健治 畑川 政勝

出版者

公益社団法人日本放射線技術学会

雑誌

日本放射線技術學會雜誌 (ISSN:03694305)

巻号頁・発行日

vol.50, no.10, pp.1726-1734, 1994-10-01

被引用文献数

7

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In the past years, receiver operating characteristic (ROC) studies that has been used in medical imaging system have involved data collected on a discrete confidence-rating scale with five categories, though in principle ROC studies which are called method for continuously-distributed test results can be conducted with continuous scale. In this study, we investigate the advantage of this new rating method. Advantages were obtained from our experiments that used both discrete and continuous rating scale with same sample sets. From the results of ROC analysis using the CR mammography with simulated mamma phantom, the method for continuously-distributed test results performs identical estimation of area under the ROC curve (Az) compared with the discrete confidence-rating method, but performs good (1/3) standard deviation of Az between readers. When the range of Az lies 0.65-0.70 which are "difficult" performance of ROC experiment, we concluded that the method for continuously-distributed test results has the advantages of good statistical power and reliability of results compared with the discrete confidencerating method.