Subband photoacoustic imaging for contrast improvement

Contrast in photoacoustic imaging is primarily determined by optical absorption. This paper proposes a subband imaging method to further enhance the image contrast. The method is based on media with different absorptions generating acoustic waves with different frequency contents. Generally, assumin...

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Bibliographic Details
Published in:Optics express 2008-12, Vol.16 (25), p.20215-20226
Main Authors: Li, Pai-Chi, Wei, Chen-Wei, Sheu, Yae-lin
Format: Article
Language:English
Subjects:
Algorithms
Elasticity Imaging Techniques - instrumentation
Elasticity Imaging Techniques - methods
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
Nephelometry and Turbidimetry - instrumentation
Nephelometry and Turbidimetry - methods
Reproducibility of Results
Sensitivity and Specificity
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Summary:Contrast in photoacoustic imaging is primarily determined by optical absorption. This paper proposes a subband imaging method to further enhance the image contrast. The method is based on media with different absorptions generating acoustic waves with different frequency contents. Generally, assuming all other conditions remain the same, a high-absorption medium generates acoustic waves with higher frequency components, and hence the imaging contrast can be enhanced by appropriate selection of the spectral subbands. This study employed both finite-difference, time-domain-based simulations and phantom imaging. The numerical results show that the peak frequencies of the signals for objects with absorption coefficients of 1 and 100 cmM(-1) were 2.4 and 7.8 MHz, respectively. Imaging an agar-based phantom further demonstrated that the contrast between two objects with absorption coefficients of 5.01 and 41.75 cm(-1) can be improved by 4-10 dB when the frequency band was changed from 0-7 to 7-14 MHz. Finally, a method to further enhance the contrast based on optimal weighting is also presented. The proposed method is of particular interest in photoacoustic molecular imaging.
ISSN:1094-4087
1094-4087
DOI:10.1364/oe.16.020215