| Project/Area Number |
07457202
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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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)
HASHIMOTO Jun Keio Univ., School of Med., Dept.of Radiology, Assistant, 医学部, 助手 (20228414)
MITAMURA Hideo Keio Univ., School of Med., Dept.of Internal Med., Associate Prof., 医学部, 助教授 (70129675)
OGAWA Satoshi Keio Univ., School of Med., Dept.of Internal Med., Professor, 医学部, 教授 (90124940)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1996: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1995: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | Single Photon Emission CT / Fanbeam collimator / Gamma camera / Transmission CT / Myocardial imaging / Truncation / Image Reconstruction / Image Processing / SPECT / 吸収補正 / モンテカルロシミュレーション |
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| Research Abstract |
In order to reconstruct the quantitative SPECT images, it is necessary to correct attenuation of the gamma rays in the body, therefore, it is desired to obtain a true atenuation map measured by gamma-ray transmission CT.Many methods and geometries of the gamma-ray transmission data acquisition system have been proposed, however, there is a limitation in the size of the scintillator and this causes a serious artifact in reconstructed images of thorax. We propose a new geometry to acquire gamma-ray transmission CT data using fanbeam collimators. In the proposed data acquisition system, we use two detectors for the acquisition of gamma-ray transmission data. The two detectors equipped with the fanbeam collimator of the same focal length rotate together around the patient body. An external gamma-ray line source located at the focal point of the fanbeam collimators rotates simultaneously as the rotation of the detectors. From the two planar images acquired by two detectors, we make an ideal transmission data having large field of view. The size of the ideal field of view can be controlled by the focal length of the fanbeam collimators. If the detector length is 40cm and the focal length changes from 50cm to 60cm, the radius of the effective field of view increases from 13.5cm to 14.4cm using a single detector. On the other hand, if we use the proposed data acquisition geometry, the radius increases from 19.2cm to 23.5cm, respectively. From the basic results, we made some simulations by changing the focal length and the detector size, and confirmed the effectivity of the proposed method. In summary, the proposed method could enlarge the field of view using an ordinary scintillator with smal size significantly, and the truncation of projection data was eliminated perfectly.
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