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Proceedings Paper

Development of an omni-directional photoacoustic source for the characterization of a hemispherical sparse detector array
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Paper Abstract

Photoacoustic imaging systems that utilize small numbers of detectors and iterative reconstruction methods require sensitive calibration of the detector array. For each voxel-detector pair, this includes the time-of-flight, fullwidth-half-maximum, and signal amplitude. The objective of this work was to develop a photoacoustic point source which emitted signal uniformly in all directions such that these features can be precisely characterized to more accurately provide an estimate of the shape and position of an acoustic signal in the imaging volume. The source was placed equidistant from acoustic detectors at different zenith and azimuthal angles from a reference position where the acoustic signal could be captured and analyzed. In the zenith direction, the signal decreased in strength by approximately 32% over the range of angles (up to 67.5°). However, in the azimuthal direction, the signal varied substantially as the source was rotated in a stationary axial position indicating imperfections over the source surface that were created during the fiber polishing procedure. The source was used to characterize time-of-flight, full-width-half-maximum, and signal amplitude at a multitude of locations within the imaging volume. While characterization maps obtained with the point source provided reasonable results, the quality of the source could be improved by constructing a truly hemispherical tip on the fiber optic.

Paper Details

Date Published: 25 February 2009
PDF: 9 pages
Proc. SPIE 7177, Photons Plus Ultrasound: Imaging and Sensing 2009, 71772F (25 February 2009); doi: 10.1117/12.809072
Show Author Affiliations
Michael Roumeliotis, Lawson Health Research Institute (Canada)
Univ. of Western Ontario (Canada)
Pinhas Ephrat, Lawson Health Research Institute (Canada)
Univ. of Western Ontario (Canada)
Jeffrey J. L. Carson, Lawson Health Research Institute (Canada)
Univ. of Western Ontario (Canada)


Published in SPIE Proceedings Vol. 7177:
Photons Plus Ultrasound: Imaging and Sensing 2009
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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