| Japanese |
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| Title | Triple Energy Window法による散乱補正が心筋SPECTの定量に及ぼす影響および2核種収集への応用 |
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| Subtitle | 原著 |
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| Authors | 中嶋憲一*, 松平正道**, 山田正人**, 滝淳一*, 利波紀久*, 久田欣一* |
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| Organization | *金沢大学医学部附属病院核医学科, **放射線部アイソトープ部門 |
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| Journal | 核医学 |
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| Volume | 32 |
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| Number | 9 |
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| Page | 959-967 |
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| Year/Month | 1995/9 |
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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」Triple energy window(TEW)法は簡便であり, 単光子核種において実際的な散乱補正法の一つである. 点線源と注射器をシンチカメラ下においたときにTEW法によって除去される散乱割合は, 201Tlでは55%, 99mTcでは29%, 123Iでは57%であった. 2核種同時収集を仮定して合成したエネルギースペクトルをTEW法で分離すると, 99mTcと201Tlではよく分離し, 201Tlと123Iでは10%程度の誤差であった. 123Iと99mTcでは非対称ウィンドウを用いることで改善が得られた. 心筋SPECT検査で検討すると散乱の影響は中隔と下壁に高く, 前壁に対する相対的な影響の割合は, 123I製剤で9%, 99mTcで7-8%, 201Tlで6%であり, 肝の集積の影響が大きな因子となった. また散乱補正を行うことにより失われるSPECTカウントは123Iで30%, 99mTcで13%, 201Tlで38%であった. さらに心筋と左室内腔のカウント比をみると, いずれの核種でも散乱補正によりコントラストは明らかに改善した. 心筋検査において, 散乱線の影響は無視できず, 実際の定量に与える程度をよく理解する必要がある. |
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| Practice | 臨床医学：一般 |
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| Keywords | Triple-energy window method, Compton scatter, Scatter correction, Myocardial SPECT, Dual-energy acquisition. |
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| English |
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| Title | Effect of Scatter Correction on Quantification of Myocardial SPECT and Application to Dual-Energy Acquisition Using Triple-Energy Window Method |
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| Subtitle | Original Articles |
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| Authors | Kenichi NAKAJIMA*, Masamichi MATSUDAIRA**, Masato YAMADA**, Junichi TAKI*, Norihisa TONAMI*, Kinichi HISADA* |
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| Authors(kana) | |
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| Organization | *Department of Nuclear Medicine, **Division of Radioisotope, Radiation Service, Kanazawa University Hospital |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 32 |
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| Number | 9 |
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| Page | 959-967 |
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| Year/Month | 1995/9 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201Tl, 29% for 99mTc, 57% for 123I. Composite energy spectra were generated and separated by the TEW method. Combination of 99mTc and 201Tl was separated well, and 201Tl and 123I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123I and 99mTc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar map and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123I, 7-8% higher in 99mTc and 6% higher in 201Tl. Apparent count loss after scatter correction was 30% for 123I, 13% for 99mTc and 38% for 201Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation. |
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| Practice | Clinical medicine |
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| Keywords | Triple-energy window method, Compton scatter, Scatter correction, Myocardial SPECT, Dual-energy acquisition. |
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