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Photoacoustic microscopy was developed to achieve volumetric imaging of the anatomy and functions of the subcutaneous microvasculature in both small animals and humans in vivo with high spatial resolution and high signal-to-background ratio. By following the skin contour in raster scanning, the ultrasonic transducer maintains focusing in the region of(More)
Photoacoustic microscopy (PAM) does not rely on contrast agent to image the optical absorption contrast in biological tissue. It is uniquely suited for measuring several tissue physiological parameters, such as hemoglobin oxygen saturation, that would otherwise remain challenging. Researchers are designing new clinical diagnostic tools and multimodal(More)
Capillaries, the smallest blood vessels, are the distal end of the vasculature where oxygen and nutrients are exchanged between blood and tissue. Hence, noninvasive imaging of capillaries and function in vivo has long been desired as a window to studying fundamental physiology, such as neurovascular coupling. Existing imaging modalities cannot provide the(More)
PURPOSE To test the capability of a novel dual-beam Doppler optical coherence tomography (OCT) technique for simultaneous in vivo measurement of the Doppler angle and, thus, the absolute retinal blood velocity and the retinal flow rate, without the influence of motion artifacts. METHODS A novel dual-beam Doppler spectral domain OCT (SD-OCT) was developed.(More)
We have developed a non-invasive photoacoustic ophthalmoscopy (PAOM) for in vivo retinal imaging. PAOM detects the photoacoustic signal induced by pulsed laser light shined onto the retina. By using a stationary ultrasonic transducer in contact with the eyelids and scanning only the laser light across the retina, PAOM provides volumetric imaging of the(More)
Functional photoacoustic microscopy (fPAM) is a hybrid technology that permits noninvasive imaging of the optical absorption contrast in subcutaneous biological tissues. fPAM uses a focused ultrasonic transducer to detect high-frequency photoacoustic (PA) signals. Volumetric images of biological tissues can be formed by two-dimensional raster scanning, and(More)
Limited-view acquisition suffers from artefacts and loss of resolution for reconstruction-based Photoacoustic Imaging (PAI). In this paper, a completely new acquisition and reconstruction scheme is reported to achieve artefact-free imaging from limited-view acquisition. The method employs spatially and temporally varying random optical illumination instead(More)
Photoacoustic molecular imaging, combined with the reporter-gene technique, can provide a valuable tool for cancer research. The expression of the lacZ reporter gene can be imaged using photoacoustic imaging following the injection of X-gal, a colorimetric assay for the lacZ-encoded enzyme β-galactosidase. Dual-wavelength photoacoustic microscopy was used(More)
PURPOSE We investigated the progressive degeneration of retinal and superior collicular functions in a mouse model of sustained ocular hypertension. METHODS Focal laser illumination and injection of polystyrene microbeads were used to induce chronic ocular hypertension. Retinal ganglion cell (RGC) loss was characterized by in vivo optical coherence(More)
Quantitatively determining physiological parameters at a microscopic level in the retina furthers the understanding of the molecular pathways of blinding diseases, such as diabetic retinopathy and glaucoma. An essential parameter, which has yet to be quantified noninvasively, is the retinal oxygen metabolic rate (rMRO2). Quantifying rMRO2 is challenging(More)