Combined photoacoustic, pulse-echo laser ultrasound, and speed-of-sound imaging using integrating optical detection

Abstract

, "Combined photoacoustic, pulse-echo laser ultrasound, and speed-of-sound imaging using integrating optical detection," J. Biomed. Opt. Abstract. A purely optical setup for the coregistration of photoacoustic (PA), ultrasound (US), and speed-ofsound (SOS) section images is presented. It extends a previously developed method for simultaneous PA and laser-US (LUS) pulse-echo imaging with a LUS transmission imaging setup providing two-dimensional (2-D) SOS maps. For transmission imaging, the sound waves traversing the investigated object are generated instantaneously by illuminating optically absorbing targets that are arranged at various distances in front of the sample. All signals are recorded by an optical beam which is part of a Mach-Zehnder interferometer that integrates the acoustic field along its path. Due to the cascaded arrangement of LUS sources, a single-recorded signal yields information for a projection of the SOS distribution. After collection of data from all directions, an inverse Radon transform is applied to this set of projections to obtain a 2-D SOS image. The setup is characterized and its performance is tested on phantom experiments. In addition to providing additional contrast, it is also shown that the resolution of the coregistered PA and LUS images can be improved by implementing the knowledge of the SOS distribution in the reconstruction. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…CW interferometry is sensitive to temperature drifts and vibrations [42]. More details about the limitations of optical ultrasound detection techniques are given in [42,[176][177][178]. Performance comparison between different optical ultrasound detectors is summarized in Table 6.…”

The Progress in Photoacoustic and Laser Ultrasonic Tomographic Imaging for Biomedicine and Industry: A Review

“…The combined "PA + LU + SoS" setup, by Wurzinder et al [57], employed optical detection of ultrasonic waves. This work expanded on the authors' earlier setup [81,103] that combined PA and pulse-echo LU imaging.…”

“…LUT was applied to the immersion ultrasound profilometry of solid samples [52,53], measurements of internal geometry of solid samples with complex external surface [54], inspection of thick welded joints [55], and evaluation of internal structure of rock samples [56] and biological objects [45,[57][58][59][60][61] (often in combination with PAT). These applications will be reviewed, in more detail, below.…”

Photoacoustic 3-D imaging of polycrystalline microstructure improved with transverse acoustic waves

“…In the first category, imaging is achieved like in traditional pulse-echo ultrasound measurements, by launching coherent acoustic pulses (CAPs) from the sample surface into its volume, and detecting the acoustic waves transmitted/scattered by the sample inhomogeneities, defects, and interfaces [12] , [13] , [14] , [15] . Since the scattered/transmitted acoustic waves are carrying information on the distribution of the acoustic inhomogeneities in the sample, the contrast in LUI is acoustical, and the spatial resolution with depth is controlled by the duration (length) of the laser-generated CAPs.…”