| Project/Area Number |
12470191
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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 | National Institute of Radiological Sciences |
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Principal Investigator |
MURAYAMA Hideo National Institute of Radiological Sciences, Department of Medical Physics, Head of Imaging Physics, 医学物理部, 室長 (50166310)
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| Co-Investigator(Kenkyū-buntansha) |
TANADA Shuji National Institute of Radiological Sciences, Department of Medical Imaging, Head of Medical Imaging, 画像医学部, 部長 (40116950)
KAWAI Hideyuki Chiba University, Department of Physics, Associate Professor, 理学部, 助教授 (60214590)
HANEISHI Hideaki Chiba University, Department of Information and Image Sciences, Associate Professor, 工学部, 助教授 (20228521)
HASEGAWA Tomoyuki Kitasato University, Department of Allied Health Sciences, Assistant, 医療衛生学部, 助手 (10276181)
OBI Takashi Tokyo Institute of Technology, Imaging Science and Engineering Laboratory, Assistant, 工学部, 助手 (40280995)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2001: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2000: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | PET / nuclear medicine / Instrumentation for diagnosis / scintillation detector / coincident count / radioisotope / image reconstruction / medical imaging |
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| Research Abstract |
Conceptual design of the next generation PET with both high sensitivity and high spatial resolution has been performed. The method for eliminating the parallax error without reducing sensitivity is to use the detector module that measures the depth of interaction (DOI) of incident gamma rays. A detector unit using a depth encoding scheme was designed and constructed for trial. The unit consists of four Gd_2SiO_5:Ce(GSO) crystal blocks in a 2x2 array coupled to a position-sensitive photomultiplier tube (PS-PMT) having metal channel dynodes and 4x4 multi-anodes. Our proposed detector should be a very reliable and simple solution suitable for volume PET devices since the proposed depth encoding scheme is constructed with all the same crystal elements and does not need additional photo-detectors nor a combination of different types of scintillators. We have estimated count rate properties of the next generation PET scanners based on the GSO detector with DOI capability using a large area PS-PMT. The proposed detector unit consists of 64 crystal blocks with four stages of 2x2 GSO arrays coupled to a 52 mm square PS-PMT which has small dead space. With appropriate light control in the crystal block, DOI information can be obtained using simple Anger-type positioning logic. Thus dead time factors can be calculated using a count rate model with standard acquisition architecture. Compton and photoelectric interactions in the scintillator and uniform cylindrical phantoms were tracked by Monte Carlo simulation programs. The preliminary results suggest that, compared to current PET scanners, high noise equivalent count rate can be obtained by the proposed scanner designs despite the relatively large size of the detector module. The count rate performance can be improved by the reduction of single events that cause block dead time losses at the cost of a slight decrease in sensitivity.
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