| Project/Area Number |
05454305
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | Keio University, School of Medicine |
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Principal Investigator |
KUBO Atsushi Keio Univ., School of Med., Dept.of Radiology, Professor, 医学部, 教授 (90051771)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Koichi Hosei Univ., College of Eng., Dept.of EE,Associate Prof., 工学部, 助教授 (00158817)
NAKAJIMA Masato Keio Univ., Faculty of Sci.and Eng., Dept.of EE,Professor, 理工学部, 教授 (20051766)
NAKAMURA Kayoko Keio Univ., School of Med., Dept of Radiology, Assistant Prof., 医学部, 専任講師 (20124480)
AMANO Takahiro Keio Univ., School of Med., Dept.of Internal Assistant Prof., 医学部, 専任講師 (90118901)
FUKUUCHI Takahiro Keio Univ., School of Med., Dept.of Internal Med., Professor, 医学部, 教授 (10051476)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Attenuation correcion / Image Processing / Single Photon Emission CT / Transmission CT / Monte Carlo method / Scatter Correction |
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| Research Abstract |
This study was carried out to obtain quantitative SPECT images by correcting attenuation and scattering of gamma rays.In the attenuation correction, we used Chang's method with an accurate map of linear attenuation coefficients measured by gamma ray fanbeam transmission CT (FTCT).FTCT scanning was performed using a commercially available gamma camera system (Toshiba GCA-9300A) with fanbeam collimators.As an external source for FTCT,we used a Tc-99m line source positioned at the focal point of each fanbeam collimator.Scatter correction was performed by eliminating the counts of scattered photons from each planar image.The method used was the triple energy window (TEW) method, in which the count data were acquired at each pixel using three windows : amain window centered at photopeak energy and two subwindows on both sides of the main window.The scattered photons included in the main window were estimated as a trapezoidal region shaped by the counts of the subwindows and the width of the main window, and were subtracted from the count of the main window.These attenuation and scatter correction methods were evaluated by simulations using a Monte Carlo method and by experiments including phantom studies and preliminary clinical studies.The results of these simulations and experiments showed that quantitative measurement of activity in an object was realized in clinical situations.
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