title: Maximum-Likelihood Estimation With a Contracting-Grid Search Algorithm.
abstract: A fast search algorithm capable of operating in multi-dimensional spaces is introduced. As a sample application, we demonstrate its utility in the 2D and 3D maximum-likelihood position-estimation problem that arises in the processing of PMT signals to derive interaction locations in compact gamma cameras. We demonstrate that the algorithm can be parallelized in pipelines, and thereby efficiently implemented in specialized hardware, such as field-programmable gate arrays (FPGAs). A 2D implementation of the algorithm is achieved in Cell/BE processors, resulting in processing speeds above one million events per second, which is a 20× increase in speed over a conventional desktop machine. Graphics processing units (GPUs) are used for a 3D application of the algorithm, resulting in processing speeds of nearly 250,000 events per second which is a 250× increase in speed over a conventional desktop machine. These implementations indicate the viability of the algorithm for use in real-time imaging applications.
authors.affiliation: Bioscan, Inc., Washington, DC 20007 USA.
authors.forename: Jacob Y
authors.initials: JY
authors.lastname: Hesterman
authors.forename: Luca
authors.initials: L
authors.lastname: Caucci
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Kupinski
authors.forename: Harrison H
authors.initials: HH
authors.lastname: Barrett
authors.forename: Lars R
authors.initials: LR
authors.lastname: Furenlid
references.citation: Med Phys. 2007 Apr;34(4):1474-86
references.pmid: 17500478
references.citation: IEEE Trans Med Imaging. 2009 Mar;28(3):435-45
references.pmid: 19244015
references.citation: IEEE Trans Nucl Sci. 2009 Feb 10;56(1):189-196
references.pmid: 20191099
references.citation: IEEE NPSS Real Time Conf. 2005 Jun;2005:498-501
references.pmid: 27066595
references.citation: IEEE Trans Nucl Sci. 2004 Jun;51(3):631-635
references.pmid: 20877439
references.citation: Med Phys. 2008 Aug;35(8):3546-53
references.pmid: 18777915
references.citation: IEEE Trans Nucl Sci. 2009 Jun 1;56(3):725
references.pmid: 20107527
references.citation: IEEE Comput Graph Appl. 2008 Sep-Oct;28(5):66-77
references.pmid: 18753036