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On the speckle‐free nature of photoacoustic tomography
Author(s) -
Guo Zijian,
Li Li,
Wang Lihong V.
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3187231
Subject(s) - speckle pattern , photoacoustic tomography , photoacoustic imaging in biomedicine , optics , photoacoustic effect , laser , photoacoustic spectroscopy , absorption (acoustics) , materials science , tomography , speckle noise , physics
Purpose: A long‐standing conundrum is why photoacoustic tomography (PAT) possesses the unique ability to produce images devoid of speckle artifacts while all other coherent imaging technologies do not. Methods: In this paper, we explain the inherent mechanism that suppresses speckle in PAT, and the analysis was validated by simulations based on an experimental PAT system. Results: We found that the speckle‐free feature of PAT results directly from the optical absorption contrast. Conclusions: All optical absorbers expand on laser excitation, and therefore all initial photoacoustic pressure rises are positive, which engenders strong correlations among the photoacoustic waves from the absorbers. As a result, prominent boundaries always build up in photoacoustic images and suppress the interior speckle.