| Japanese |
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| Title | コリメータ開口特性によるECT画像の画質劣化の補正 |
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| Subtitle | 原著 |
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| Authors | 白承権*, 尾川浩一**, 中島真人* |
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| Organization | *慶応義塾大学理工学部電気工学科, **慶応義塾大学医学部放射線医学教室 |
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| Journal | 核医学 |
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| Volume | 24 |
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| Number | 10 |
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| Page | 1539-1545 |
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| Year/Month | 1987/10 |
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| Article | 原著 |
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| Publisher | 日本核医学会 |
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| Abstract | 「要旨」 Single Photon Emission CT (SPECT) の画質劣化問題の一つにコリメータの開口特性の問題がある. これはコリメータが有限の長さを持つ筒形状をなすことに起因するものであり, 再生像上ではShift-variantなボケとして現われる. この補正法として測定投影データを周波数空間上で, 近似的にShift-invariantな系に置き換え, デコンボリューションする方法を開発した. 今回, コリメータの種類 (開口角) とコリメータ・被検体間の距離をパラメータとして, 実際の応用を考慮したシミュレーションを実施し, 補正法の有効性およびその限界を検討した. 「I. はじめに」 Single Photon Emission CT (SPECT) は体内臓器における放射性同位元素の分布を定量的に映像化することを目指したものであるが, 被検体内部での放射線の減衰, 散乱, コリメータ等の影響により, 再構成画像に画質劣化が生じ, 現段階では定性的な診断を行う程度にとどまっている. |
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| Practice | 臨床医学：一般 |
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| Keywords | Single photon emission CT, Collimator aperture, Image distortion, Shift-variant blurring, Circular deconvolution |
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| English |
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| Title | Correction of Single Photon Emission CT Image Distorted by Collimator Aperture |
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| Subtitle | Original Articles |
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| Authors | Seungkuen PAEK*, Koichi OGAWA**, Masato NAKAJIMA* |
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| Authors(kana) | |
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| Organization | *Department of Electrical Engineering, Faculty of Science and Technology, Keio University, **Department of Radiology, School of Medicine, Keio University |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 24 |
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| Number | 10 |
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| Page | 1539-1545 |
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| Year/Month | 1987/10 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] In single photon emission computed tomography, one of the distortions of a reconstructed image is related to a collimator system. The distortion, which has a shift-variant property, is caused by a geometrical structure of the collimator. We developed a correction method considering this property. In this method, the correction is performed in the frequency domain. The conception of the correction method is that the blurring function is defined at the circular position of the polar coordinate in the frequency domain, the cyclic deconvolution of projection data with the shift-variant blurring function is effective to remove the distortion. In this paper, we considered the effect of aperture angle and that of distance between the surface of the gamma camera and the rotational center of the gamma camera. Moreover the applicability to clinical studies was discussed. |
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| Practice | Clinical medicine |
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| Keywords | Single photon emission CT, Collimator aperture, Image distortion, Shift-variant blurring, Circular deconvolution |
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