| Japanese |
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| Title | 第1回循環時法左室駆出分画測定における吸収補正の試み |
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| Subtitle | 原著 |
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| Authors | 与那嶺茂道*, 外山比南子*, 村田啓*, 千葉茂*, 熊谷欣也*, 山田英夫*, 飯尾正宏** |
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| Organization | *養育院附属病院核医学放射線部, **東京大学医学部放射線科 |
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| Journal | 核医学 |
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| Volume | 19 |
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| Number | 8 |
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| Page | 1137-1145 |
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| Year/Month | 1982/9 |
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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」 第1回循環時法により右前斜位で採取した左心室ゲートイメージでは, 右室血液プールによる吸収の影響で, 真の左室計数が得られない. この左室放射能の右室による吸収を, 右室のゲートイメージを用いて補正する方法を考案した. すなわち, 右室ゲートイメージ中の1絵素の計数をDA (xi, yi), 右室の放射能密度と効率の積をρA, 左室計数をDs (xi, yi) とすると吸収補正後の左室内1絵素の計数 S0 (xi, yi) は, Ds (xi, yi) {ρA/ (ρA - DA (xi, yi) ・μA) } で求められる. ここでμAはγ線の吸収係数である. ρAをパラメータとして計算し, 適当な吸収補正を行うρAを求め得ることをファントム実験および, 臨床例で確認した. 正常者10例について吸収補正して求めた駆出分画を未補正および平衡時法で求めた値と比較すると, 吸収補正をした場合には, 未補正の駆出分画よりも相対的に10%高値を示した. また10例中9例で平衡時法で求めた駆出分画よりも高値を示した. |
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| Practice | 臨床医学：一般 |
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| Keywords | First pass method, Attenuation correction, Ejection fraction |
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| English |
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| Title | A Trial for Attenuation Correction of the Left Ventricular Activity on First Pass Study |
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| Subtitle | Original Articles |
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| Authors | Shigemichi YONAMINE*, Hinako TOYAMA*, Hajime MURATA*, Shigeru CHIBA*, Kinya KUMAGAI*, Hideo YAMADA*, Masahiro IIO** |
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| Authors(kana) | |
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| Organization | *Department of Nuclear Medicine and Radiological Science, Tokyo Metropolitan Geriatric Hospital, **Department of Radiology, Tokyo University |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 19 |
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| Number | 8 |
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| Page | 1137-1145 |
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| Year/Month | 1982/9 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] The radioactivity in the left ventricle with the first pass method in the RAO projection are attenuated by the right ventricular blood pool. The amount of attenuation is proportional to the thickness (TA) of the right ventricle, which can be estimated from the RV counts (DA) ; Da∝ρA・Ta. Where ρA is counts/cm. The range of ρA values can be roughly estimated from the RV gated images. The attenuation LV counts Ds is represented in S0・e (-μATA), using true LV counts S0 without attenuation and attenuation coefficient μA (0.15 for Er = 140 kev). Then the LV counts after correction S0 is expressed as DS {ρA/ (ρA - DaμA) }. The LV gated image at each phase was corrected by a pixel-by-pixel for ρA = 4 to 10 using the RV gated image at the same phase. Ejection fraction (EF) was also calculated after the attenuation correction for each ρA and found to have a peak value for a limited ρA. It was found from the images and EF that good attenuation correction were about 10% higher than those without correction. In nine of ten cases, corrected EF was slightly higher than those obtained by equilibrium method. An adequate ρA for the attenuation correction was obtainable in a short region of ρA. This method of attenuation correction can be applied to the clinical study. |
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| Practice | Clinical medicine |
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| Keywords | First pass method, Attenuation correction, Ejection fraction |
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