| Japanese |
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| Title | 201Tlイメージングにおけるoff - peak triple energy window収集による散乱線補正 |
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| Subtitle | 原著 |
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| Authors | 古嶋昭博*, 松本政典**, 大山洋一***, 冨口静二***, 吉良光子***, 高橋睦正*** |
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| Organization | *熊本大学アイソトープ総合センター, **熊本大学医療技術短期大学部診療放射線技術学科, ***熊本大学医学部放射線科 |
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| Journal | 核医学 |
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| Volume | 34 |
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| Number | 9 |
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| Page | 789-796 |
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| Year/Month | 1997/9 |
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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」201Tlイメージングでのtriple energy window(TEW)収集による散乱線補正に関して, off-peak TEW(OFPTEW)法を考案した. このOFPTEW法では, 73 keVに中心を持つ34 keV幅のメインウィンドウと5.1keVの両サブウィンドウ収集法を使用し, 散乱線除去係数0.55を用いて散乱線補正を行う. ファントムを用いたプラナーとSPECTイメージングでOFPTEW法による散乱線補正を行い, 散乱線カウントを台形近似して散乱線補正する従来のTEW法(70 keV中心で14 keV幅のメインウインドウと49keV幅のサブウインドウ)と比較した. 線線源と完全欠損を持つ板状線源のプラナーイメージングでは, 両方法による散乱線補正イメージは, 視覚的によく似ていた. しかし, OFPTEW法は直接線カウントの推定および欠損部でのコントラスト算出を精度良くできたのに対し, 従来のTEW法は直接線のカウントを30%過小評価し, コントラスト算出能も悪かった. 心筋ファントムのSPECTイメージングでは, 欠損や内腔の描出については従来法と変わらなかったが, 散乱線補正後の心筋イメージカウント数は約1.46倍になった. 201Tlイメージングにおいて, このOFPTEW法は, 従来のTEW法よりも直接線の計数率を増加させるような散乱線補正ができることがわかった. |
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| Practice | 臨床医学：一般 |
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| Keywords | 201Tl imaging, Scatter correction, Triple energy window method, Off-peak energy window, Scatter correction factor. |
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| English |
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| Title | Scatter Correction with an Off - Peak Triple Energy Window Method in Thallium - 201 Imaging |
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| Subtitle | Original Articles |
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| Authors | Akihiro KOJIMA*, Masanori MATSUMOTO**, Yoichi OHYAMA***, Seiji TOMIGUCHI***, Mitsuko KIRA***, Mutsumasa TAKAHASHI*** |
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| Organization | *Radioisotope Research Center, Kumamoto University, **Department of Radiological Technology, Kumamoto University College of Medical Science, ***Department of Radiology, Kumamoto University School of Medicine |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 34 |
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| Number | 9 |
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| Page | 789-796 |
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| Year/Month | 1997/9 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary]For scatter correction using the triple energy window(TEW)acquisition in 201Tl imaging, we propose an off-peak TEW(OFPTEW)method. This OFPTEW method employs a wide main energy window of 34 keV centered at 73 keV and two 5.1 keV sub-energy windows and uses the scatter correction factor of 0.55. To assess scatter correction using the OFPTBW method in 201Tl imaging, phantom studies for planar and SPECT imaging were performed and the data with the OFPTEW method were compared with those by the conventional TEW method using the trapezoidal formula with the 20%main energy window centered at 70 keV and two 4.9 keV sub-energy windows. The planar images corrected by both methods were visually similar. The OFPTEW method, however, estimated the true primary counts and the contrast value in the cold lesion accurately, while the conventional TEW method underestimated the primary counts by 30%and gave wrong contrast values. For the myocardial SPECT imaging, the short-axis images by both methods were very similar, but the images by the OFPTEW method had 1.46 times more counts than those corrected by the conventional TEW method. In conclusion, the OFPTEW method can correct scatter in 201Tl imaging accurately and increase the primary counts effectively compared with the conventional TEW method. |
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| Practice | Clinical medicine |
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| Keywords | 201Tl imaging, Scatter correction, Triple energy window method, Off-peak energy window, Scatter correction factor. |
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