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Multiple-Hit Parameter Estimation in Monolithic Detectors

delete2013-02-01
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OA
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William C. Hunter *
H
Harrison H. Barrett
R
Robert S. Miyaoka
DOI:10.1109/TMI.2012.2226908delete
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Abstract

Abstract

En 中文
We examine a maximum-a-posteriori method for estimating the primary interaction position of gamma rays with multiple interaction sites (hits) in a monolithic detector. In assessing the performance of a multiple-hit estimator over that of a conventional one-hit estimator, we consider a few different detector and readout configurations of a 50-mm-wide square cerium-doped lutetium oxyorthosilicate block. For this study, we use simulated data from SCOUT, a Monte-Carlo tool for photon tracking and modeling scintillation-camera output. With this tool, we determine estimate bias and variance for a multiple-hit estimator and compare these with similar metrics for a one-hit maximum-likelihood estimator, which assumes full energy deposition in one hit. We also examine the effect of event filtering on these metrics; for this purpose, we use a likelihood threshold to reject signals that are not likely to have been produced under the assumed likelihood model. Depending on detector design, we observe a 1%-12% improvement of intrinsic resolution for a 1-or-2-hit estimator as compared with a 1-hit estimator. We also observe improved differentiation of photopeak events using a 1-or-2-hit estimator as compared with the 1-hit estimator; more than 6% of photopeak events that were rejected by likelihood filtering for the 1-hit estimator were accurately identified as photopeak events and positioned without loss of resolution by a 1-or-2-hit estimator; for PET, this equates to at least a 12% improvement in coincidence-detection efficiency with likelihood filtering applied.
Keywords:
Detector scatter
Gamma-ray imaging
maximum likelihood estimation
monolithic detectors
multiple-hit positioning
three-dimensional (3-D) interaction positioning
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Journal

IEEE Transactions on Medical Imaging cover
IEEE Transactions on Medical Imaging
IF:
9.8
Papers:
6.2K
Citations:
3.7W

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U
University of Washington
Scholars:
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Papers: 7.0W
Citations: 12.5W