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Beating the photoacoustic imaging diffraction limit using flow-induced absorption fluctuation (Conference Presentation)
Author(s): Bastien Arnal; Thomas Chaigne; Sergey Vilov; Emmanuel Bossy; Ori Katz
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Paper Abstract

The resolution of photoacoustic imaging of blood vasculature is limited at depth by the acoustic diffraction limit. In this work, we propose to exploit the fluctuations caused by flowing absorbers (such as red blood cells in blood vessels) to perform photoacoustic imaging beyond the acoustic diffraction limit: following the super-resolution optical fluctuation imaging (SOFI) method, we analyze the n-th order statistics from the temporal photoacoustic fluctuations induced by flowing particles. We performed a proof-of-concept experiment in a 5-channel microfluidic silicon-based circuit flown with a suspension of RBC-mimicking 10 µm red-tainted polymer spheres (Microparticles, GmbH, Berlin, Germany). The sample was illuminated with a 5 ns pulsed ND-YAG laser (532 nm, Innolas, Krailling, Germany) with a fluence of 3 mJ/cm^2 and imaged at a 20 Hz rate using a L22-8v probe (128 elements, Verasonics, Redmond, WA, USA) coupled to a Verasonics Vantage 256 ultrasound scanner. Whereas the resolution of conventional photoacoustic imaging was too low to resolve individual channels, the nth order statistical analysis of the photoacoustic fluctuations provided images with a resolution enhancement scaling as n^{1/2}, in agreement with the SOFI theory and with numerical simulations. As opposed to our previous work which exploited speckle-based photoacoustic fluctuations to increase the resolution, the approach proposed here based on sample fluctuations do not require coherent light and can be readily applied to conventional photoacoustic imaging setup. Furthermore, in order to discard the oscillatory behavior of the photoacoustic point-spread-function, we extended in this work the SOFI theory to complex-valued photoacoustic images.

Paper Details

Date Published: 15 March 2018
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Proc. SPIE 10494, Photons Plus Ultrasound: Imaging and Sensing 2018, 104941T (15 March 2018); doi: 10.1117/12.2287407
Show Author Affiliations
Bastien Arnal, Lab. Interdisciplinaire de Physique, Univ. Grenoble Alpes (France)
Ctr. National de la Recherche Scientifique (France)
Thomas Chaigne, Charité Universitätsmedizin Berlin (Germany)
Humboldt-Univ. zu Berlin (Germany)
Sergey Vilov, Lab. Interdisciplinaire de Physique, Univ. Grenoble Alpes (France)
Ctr. National de la Recherche Scientifique (France)
Emmanuel Bossy, Lab. Interdisciplinaire de Physique, Univ. Grenoble Alpes (France)
Ctr. National de la Recherche Scientifique (France)
Ori Katz, The Hebrew Univ. of Jerusalem (Israel)


Published in SPIE Proceedings Vol. 10494:
Photons Plus Ultrasound: Imaging and Sensing 2018
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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