Medical Imaging and Information Sciences

New and Effective approach to standardized installation of Medical information system using IHE (Integrating the Healthcare Enterprise) Technical Framework.

Minoru HOSOBA

2003 Volume 20 Issue 2 Pages 82-91
Published: 2003
Released on J-STAGE: August 27, 2012

DOIhttps://doi.org/10.11318/mii1984.20.82

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Present and future of flat panel detectors in the world

Kiyonari INAMURA

2003 Volume 20 Issue 2 Pages 92-97
Published: 2003
Released on J-STAGE: August 27, 2012

DOIhttps://doi.org/10.11318/mii1984.20.92

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Present status of development of flat panel detectors and their clinical application in the world have been surveyed, and future trends are also explored especially in the field of material researches and methods of manufacturing. Also the importance of role of medical physicists in user side is described because characteristic physics measurement of a detector assembly is in avoidable and essential in quality assurance in clinical routine and acceptance test in hospitals.
Even though physics measurements and cli-nical evaluations on flat panel detectors have shown remarkable progress and advances in these several years, future problems of cost down in manufacturing and quality assurance to prevent individual differences between detector assem-blies must be resolved.
Results of evaluation in mammography, chest radiography, fluoroscopy for cardiovascular exa-mination, bone tumor examination and radiotherapy application indicate that flat panel detectors are future promising materials. Their systematic operation is contributing to heighten accuracy of image examinations and preciseness of radiation therapy. Encouragement to medical physicists relevant to flat panel detectors is also raised in this paper.

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Analysis of 4-D CT Images Degraded by Motion Artifacts

Yi-Qiang YANG, Nobuyuki NAKAMORI, Yasuo YOSHIDA

2003 Volume 20 Issue 2 Pages 98-103
Published: 2003
Released on J-STAGE: August 27, 2012

DOIhttps://doi.org/10.11318/mii1984.20.98

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4-D computed tomography (CT) scanner provides a dynamic volumetric imaging and good contrast detectablity with a high speed for collecting projections. In spite of these merits, some motion effects such as respiration, cardiac motion, and patient restlessness produce artifacts that appear as blurring, doubling, and distortion in the reconstructed images, and may lead to inaccurate diagnosis. To reduce these negative effects on reconstructed CT images, we have developed an approximative thorax phantom to analyze the motion effect in 4-D CT for testing the performance of the algorithm. The semi-anthropomorphic raw projections are obtained by based on this phantom with less computer resources. We simply simulate the motion artifacts and apply a knowledge-based method to improve the reconstructed images.

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Classification method of mammographic microcalcifications by using high-resolution mammograms

Norimitsu SHINOHARA, Takeshi HARA, Hiroshi FUJITA, Takuji LWASE, Tokik ...

2003 Volume 20 Issue 2 Pages 104-111
Published: 2003
Released on J-STAGE: August 27, 2012

DOIhttps://doi.org/10.11318/mii1984.20.104

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We have been developing a computer-aided diagnosis (CAD) system for mammograms. The system detects clustered area of mammographic microcalcifications based on density gradient analysis, and classifies the candidates into benign or malignant according to the feature analysis. Although the image digitized with 100-μm sampling distance (“100-μm image”) was used in our previous study, the image digitized with 50-μm sampling distance(“50-μm image”) would be used to improve the classification performance because the precise shape of microcalcification may be extracted from these images. In this study, we propose a technique of classifying clustered microcalcifications using 50-μm image. The re-detection processing by 50-μm image including noise reduction processing based on smoothing technique is newly added to our conventional method. As a result of applying this technique to 85 cases (137 ROIs),10% of improvement was achieved in terms of a correct answer rate, and the validity of this technique was investigated by ROC analysis. It was concluded that the classification of clustered microcalcifications with higher accuracy was obtained from these procedures of using a highresolution image(50-μm image)effetively.

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