3 research outputs found
Multi-scale volumetric dynamic optoacoustic and laser ultrasound (OPLUS) imaging enabled by semi-transparent optical guidance
Major biological discoveries have been made by interrogating living organisms
with light. However, the limited penetration of unscattered photons within
biological tissues severely limits the depth range covered by optical methods.
Deep-tissue imaging has been achieved by combining light and ultrasound.
Optoacoustic imaging uniquely exploits optical generation of ultrasound to
render high-resolution images at depths unattainable with optical microscopy.
Recently, laser ultrasound has further been suggested as a means of generating
broadband acoustic waves for high-resolution pulse-echo ultrasound imaging.
Herein, we propose an approach to simultaneously interrogate biological tissues
with light and ultrasound based on layer-by-layer coating of silica optical
fibers with a controlled degree of transparency. We exploit the time separation
between optoacoustic signals and ultrasound echoes collected with a custom-made
spherical array transducer for simultaneous three-dimensional optoacoustic and
laser ultrasound (OPLUS) imaging with a single laser pulse. OPLUS is shown to
enable large-scale comprehensive anatomical characterization of tissues along
with functional multi-spectral imaging of spectrally-distinctive chromophores
and assessment of cardiac dynamics at ultrafast rates only limited by the pulse
repetition frequency of the laser. The suggested approach provides a flexible
and scalable means for developing a new generation of systems synergistically
combining the powerful capabilities of optoacoustics and ultrasound imaging in
biology and medicine.Comment: 21 pages, 4 figure
Optoacoustic imaging with an air-coupled transducer using coaxially aligned focused illumination
Optoacoustic (OA) methods have become powerful tools in biomedical research capable of retrieving functional information from biological tissues in vivo. Acquisition of OA signals generally relies on direct physical contact of a transducer or an acoustic coupling medium with the tissue surface, which prevents applicability, e.g., in open surgeries or wounded tissues. Non-contact OA imaging has been achieved with air-coupled piezoelectric transducers, which provide a straightforward approach for remote sensing of ultrasound vibrations. However, sensitivity was hampered by a suboptimal alignment between the illumination and detection fields. Herein, we devised an air-coupled transducer featuring a central aperture for light delivery with coaxially aligned optical and acoustic foci, thus providing optimal sensitivity for OA signal detection. Imaging of phantoms and a mouse ear in vivo is showcased by raster-scanning the transducer with light being delivered through a multimode optical fiber