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Proceedings Paper

Photon-counting gamma camera based on columnar CsI(Tl) optically coupled to a back-illuminated CCD
Author(s): Brian W. Miller; H. Bradford Barber; Harrison H. Barrett; Liying Chen; Sean J. Taylor
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Paper Abstract

Recent advances have been made in a new class of CCD-based, single-photon-counting gamma-ray detectors which offer sub-100 μm intrinsic resolutions.1-7 These detectors show great promise in small-animal SPECT and molecular imaging and exist in a variety of cofigurations. Typically, a columnar CsI(Tl) scintillator or a radiography screen (Gd2O2S:Tb) is imaged onto the CCD. Gamma-ray interactions are seen as clusters of signal spread over multiple pixels. When the detector is operated in a charge-integration mode, signal spread across pixels results in spatial-resolution degradation. However, if the detector is operated in photon-counting mode, the gamma-ray interaction position can be estimated using either Anger (centroid) estimation or maximum-likelihood position estimation resulting in a substantial improvement in spatial resolution.2 Due to the low-light-level nature of the scintillation process, CCD-based gamma cameras implement an amplfication stage in the CCD via electron multiplying (EMCCDs)8-10 or via an image intensfier prior to the optical path.1 We have applied ideas and techniques from previous systems to our high-resolution LumiSPECT detector.11, 12 LumiSPECT is a dual-modality optical/SPECT small-animal imaging system which was originally designed to operate in charge-integration mode. It employs a cryogenically cooled, high-quantum-efficiency, back-illuminated large-format CCD and operates in single-photon-counting mode without any intermediate amplfication process. Operating in photon-counting mode, the detector has an intrinsic spatial resolution of 64 μm compared to 134 μm in integrating mode.

Paper Details

Date Published: 28 March 2007
PDF: 7 pages
Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65100N (28 March 2007); doi: 10.1117/12.710109
Show Author Affiliations
Brian W. Miller, College of Optical Sciences, Univ. of Arizona (United States)
H. Bradford Barber, College of Optical Sciences, Univ. of Arizona (United States)
Harrison H. Barrett, College of Optical Sciences, Univ. of Arizona (United States)
Liying Chen, College of Optical Sciences, Univ. of Arizona (United States)
Sean J. Taylor, Lockheed Martin Space Systems (United States)

Published in SPIE Proceedings Vol. 6510:
Medical Imaging 2007: Physics of Medical Imaging
Jiang Hsieh; Michael J. Flynn, Editor(s)

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