| Japanese |
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| Title | 近似的3次元画像再構成によるコーンビームSPECTの線源応答解析 |
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| Subtitle | 原著 |
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| Authors | 村山秀雄*, 野原功全* |
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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 | 28 |
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| Number | 9 |
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| Page | 1041-1047 |
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| Year/Month | 1991/9 |
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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」コーンビームSPECTで得られるコーンビーム投影データの3次元画像再構成問題において, カメラの走査方式や再構成演算を簡素化するために, 2次元ファンビーム投影用のアルゴリズムを適用する近似的画像再構成法の可能性を検討した. 回転軸と直交する面で逆投影を行うことにより演算時間を短縮した. この近似的な画像再構成法における再構成画像のひずみと分解能の劣化を点線源応答に関するコンピュータ・シミュレーションにより分析した. その結果, 画像の劣化度を定量的に示すことができた. また, この劣化度をコリメータの焦点距離や回転半径によらずに表す方法を求め, 任意の幾何学的配置に対しても劣化度を予測できる資料を提供した. 「I. はじめに」放射型CTは本来3次元の画像再構成をめざしており, 生体内から全方向に放出される放射線をできるだけ多く検出してRIの3次元分布像の画質を向上することが望まれる. |
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| Practice | 臨床医学：一般 |
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| Keywords | Single photon emission CT, Cone-beam projection, Three-dimensional image reconstruction. |
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| English |
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| Title | Response Analysis for an Approximate 3-D Image Reconstruction in Cone-beam SPECT |
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| Subtitle | Original Articles |
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| Authors | Hideo MURAYAMA, Norimasa NOHARA |
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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 | 28 |
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| Number | 9 |
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| Page | 1041-1047 |
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| Year/Month | 1991/9 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary]Cone-beam Single Photon Emission Computed Tomography (SPECT) offers the potential for a large increase in sensitivity as compared with parallel hole or fan-beam collimation. Three-dimensional image reconstruction was approximately accomplished by backprojecting filtered projections using a two-dimensional fan-beam algorithm. The cone-beam projection data were formed from mathematical phantoms as analytically derived line integrals of the density. In order to reduce the processing time, the filtered projections were backprojected into each planes parallel to the circle on which the focal point moved, Discrepancy of source position and degradation of resolution were investigated by computer simulation in three-dimensional image space. The obtained results suggest that, the nearer to the central plane or the axis of rotation, the less image degradation is performed. By introducing a parameter of angular difference between the focal point and a fixed point in the image space during rotation, degradation of the reconstructed image can be estimated for any cone-beam SPECT system. |
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| Practice | Clinical medicine |
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| Keywords | Single photon emission CT, Cone-beam projection, Three-dimensional image reconstruction. |
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