| Japanese |
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| Title | 中央部重点型コリメータ系によるシングルフォトンECTの画質改善法 |
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| Subtitle | 《原著》 |
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| Authors | 村山秀雄*, 野原功全*, 田中栄一* |
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| Organization | *放射線医学総合研究所物理研究部 |
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| Journal | 核医学 |
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| Volume | 23 |
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| Number | 10 |
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| Page | 1351-1360 |
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| Year/Month | 1986/10 |
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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」: シングルフォトンECTにおいて検出視野の中央部で高い検出感度をもつ中央部重点型コリメータ系を用いる方式を検討した. 中央部重点型重み関数を導入して投影データの収集を行えば, 画像中央の雑音特性が向上することを計算機によるシミュレーション実験によって明らかにした. この方式は, 特に円環状線源に囲まれたコールド領域内において局所的な線源の有無を判定する場合に有益である. 中央部重点型コリメータ系を実現する一案として, 複数のガンマカメラに互いに焦点距離の異なる1次元単一収束型コリメータを取り付ける方式を考案し, その方式によるSPECT画像の雑音特性が向上することを明らかにした. |
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| Practice | 臨床医学：一般 |
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| Keywords | Single photon emission computed tomography, Collimator, Weighting function, Statistical noise, Computer simulation. |
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| English |
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| Title | Improvement on Image Quality of Single Photon ECT with Converging Collimator System |
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| Subtitle | Original Articles |
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| Authors | Hideo MURAYAMA, Norimasa NOHARA, Eiichi TANAKA |
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| Authors(kana) | |
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| Organization | Division of Physics, National Institute of Radiological Sciences |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 23 |
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| Number | 10 |
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| Page | 1351-1360 |
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| Year/Month | 1986/10 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] : Single photon emission computed tomography (SPECT) with converging collimator system was proposed to improve quality of reconstructed images. The collimator system was designed to enhance sensitivity at the center region of field-of-view, where the probability photons escape the attenuating medium is smaller than at the off-center region. In order to evaluate efficiency of the improvement on image quality, the weighting function of projection, which is defined as relative sensitivity to the average on the lateral sampling of projection, was adopted to the image reconstruction algorithm of Radial Post Correction method. Statistical mean square noise in a reconstructed image was formulated in this method. Simulation studies using typical weighting function showed that center-enhanced weighting function brings effective improvement on image quality, especially, at the center region of cold area surrounded by annularly distributed activity. A new SPECT system was proposed as one example of the converging collimator systems. The system is composed of four gamma cameras with four fan-beam collimators, which have different focal distances one another. Simple simulation studies showed that the proposed system has reasonable center-enhanced weighting function, and the image quality based on the proposed system was fairly improved as compared with one based on uniform weighting function at the center region of the field-of-view. |
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| Practice | Clinical medicine |
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| Keywords | Single photon emission computed tomography, Collimator, Weighting function, Statistical noise, Computer simulation. |
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