| Japanese |
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| Title | 心臓Single Photon Emission Computed Tomographyにおける不均一吸収体の影響 - シミュレーション実験による検討 - |
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| Subtitle | 原著 |
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| Authors | 細羽実*, 和迩秀信*, 外山比南子**, 村田啓***, 田中栄一**** |
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| Organization | *島津製作所医用技術部, **筑波大学医学部核医学科, ***虎の門病院核医学科, ****放射線医学総合研究所 |
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| Journal | 核医学 |
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| Volume | 23 |
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| Number | 5 |
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| Page | 481-488 |
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| Year/Month | 1986/5 |
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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」SPECT (Single Photon Emission Computed Tomography) の吸収補正は体表輪郭内で均一な吸収体を仮定して行われているが, 胸部のSPECT, 特に心臓においては, 吸収係数が大きく異なる不均一な吸収体の分布による誤差が問題になる. 著者らは心電図同期MRI (Magnetic Resonance Imaging) 像を用いて, 吸収体およびRIの分布をトレースし, 投影像を作成した. 再構成は, 一様吸収体を仮定した場合と不均一な吸収体を仮定した場合のそれぞれにおいて行い, かつ各吸収補正法ごとに再構成像のRI濃度の差異を検討した. RIの分布は, 心筋領域にとることによりTl-201・心筋SPECTを, 心プール領域にとることによりTc-99m・心電同期心プールSPECTをそれぞれシミュレートした. これにより各吸収補正法による心SPECTイメージの精度限界の推定を試みた. 比較に用いた吸収補正法は, PRE CORRECTION法, POST CORRECTION法, 荷重逆投影法, RADIAL POST CORRECTION法である. |
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| Practice | 臨床医学：一般 |
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| Keywords | Tl-201 myocardial SPECT, Tc-99m gated blood pool SPECT, Attenuation correction, Radial post correction |
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| English |
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| Title | Effects of Non-uniform Attenuators on Cardiac Single Photon Emission Computed Tomography - Simulation Experiments - |
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| Subtitle | Original Articles |
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| Authors | Minoru HOSOBA*, Hidenobu WANI*, Hinako TOYAMA**, Hajime MURATA***, Eiichi TANAKA**** |
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| Organization | *Shimadzu Corporation, **Tsukuba University, ***Toranomon Hospital, ****National Institute of Radiological Sciences |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 23 |
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| Number | 5 |
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| Page | 481-488 |
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| Year/Month | 1986/5 |
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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 effects of the non-uniform attenuators on the cardiac SPECT (Single Photon Emission Computed Tomography) have been evaluated by using the computer simulation technique. The models with realistic structures were created by tracing the outline of attenuators and the activity distributions on the gated MRI images. Fifteen slices in three normal volunteers were used to generate the SPECT images with 64 linear samplings and 64 views over 360 degree. Two types of the models, the uniform attenuator model (UAM) and the non-uniform attenuator model (NUAM), were generated simulating both the Tc-99m blood pool SPECT (TC) and Tl-201 myocardial SPECT (TL). Images were then reconstructed with the various attenuation correction techniques including the pre-correction (PRE), the post-correction (POST), the Weighted Backprojection (WBP), and the Radial Post Correction method (RPC). The results were compared with the true images reconstructed from a model without assuming no attenuators and a relative percent error (%ERROR) was calculated in the cardiac region. The RPC has shown lowest %ERROR in UAM (11%). However twenty to thirty percent %ERROR increase has been observed for NUAM reconstructed with the RPC, WBP, and POST method. They were considered to be caused by larger attenuation coefficient used in the reconstruction. Introducing of an average attenuation coefficient (0.12/cm for Tc-99m and 0.14/cm for Tl-201) in the RPC method decreased %ERROR to the levels of UAM. |
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| Practice | Clinical medicine |
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| Keywords | Tl-201 myocardial SPECT, Tc-99m gated blood pool SPECT, Attenuation correction, Radial post correction |
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