| Japanese |
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| Title | コンプトン散乱断層の基礎的研究 |
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| Subtitle | 原著 |
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| Authors | 遠藤真広*, 松本徹*, 飯沼武*, 舘野之男* |
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| Organization | *放射線医学総合研究所臨床研究部 |
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| Journal | 核医学 |
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| Volume | 16 |
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| Number | 2 |
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| Page | 175-181 |
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| Year/Month | 1979/4 |
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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」シンチカメラを利用するコンプトン散乱断層 (CST) の物理的特性をファントーム実験により検討した. 0.5〜2.5Ciの192Ir線源を鉛製の照射器に入れγ線ビームを扇形にコリメートして被写体に照射した. この際, 線源を回転させ照射は90°ごとの4方向より行なった. 90°方向の散乱線を垂直上方におかれた東芝製のシンチカメラGCA-202により検出し, 電子計算機TOSBAC-3400にオンライン収集した. 同じ計算機により収集した4方向の画像を重ね合わせ, さらにカメラの不均一性補正と1次線の減弱補正を行なった. 計数率は計算と一致し, 画像の一様性は数パーセントであり, 分解能はFWHMではかつて15mmであり, 電子密度の測定値の相対的な大きさは予想と一致した. この方法のCSTはCTにくらべて効率が悪い点を指摘し, その点を改良するコリメータを提案した. さらに, いくつかの臨床応用の可能性を考察した. |
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| Practice | 臨床医学：一般 |
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| Keywords | Compton scatter tomography, image processing, image quality |
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| English |
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| Title | Physical Characteristics of Compton Scatter Tomography |
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| Subtitle | Original Articles |
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| Authors | Masahiro ENDO, Toru MATSUMOTO, Takeshi A.IINUMA, Yukio TATENO |
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| Authors(kana) | |
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| Organization | Division of Clinical Research, National Institute of Radiological Sciences |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 16 |
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| Number | 2 |
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| Page | 175-181 |
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| Year/Month | 1979/4 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] Compton scatter tomography (CST) is a hopeful imaging method aquiring tomographic distributions of the electron density. We have studied this method by phantom experiments. An object was irradiated by a rotating fan-shaped gamma ray and orthogonally scattered irradiations were detected by a conventional scintillation camera, which thereby imaged the irradiated section of the object. 192Ir was selected as the gamma ray source since high disintegration rate (1-5Ci) necessary for clinical use can be easily obtained and it has a moderate half-life (74 days) and a peak energy (300 kev). We used 0.5-2.5 Ci source in this study and objects were irradiated from four directions whose angular spacing was 90 degrees. A Toshiba GCA-202 camera was used as a detector and a Toshiba TOSBAC-3400 computer system was used for data collections. Each image was made of 64×64 pixels and the pixel width was 5 mm. The same computer was also used for image processings, which in this study consisted of (1) superimposing of four images obtained by different directions, (2) correction of the non-uniformity of the camera, and (3) correction of the attenuation of the primary ray. Some physical characteristics were measured by the phantom study. Counting rates were agreed with calculations. There was a few percent variations for images of a uniform object (water phantom). The resolution was 15 mm in FWHM and was limited by the camera's overall resolution. Measured values of the electron density were agreed with expected values. An efficiency of the exposure dose of this method was considered in the context of the noise and the resolution and was shown much poorer than that of a CT-scanner. This was partly attributed to the very small effeiciency of the conventional collimator. We proposed a new collimator which was very effective for CST. Some clinical applications were suggested. Above all, an application to on-line dose monitoring of radiation therapy was emphasized. |
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| Practice | Clinical medicine |
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| Keywords | Compton scatter tomography, image processing, image quality |
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