Category «Publications»

Rapid functional optoacoustic micro- angiography in a burst mode

Optoacoustic microscopy (OAM) can image intrinsic optical absorption contrast at depths of several millimeters where state-of-the-art optical microscopy techniques fail due to intense light scattering in living tissues. Yet, wide adoption of OAM in biology and medicine is hindered by slow image acquisition speed, small field of view (FOV), and/or lack of spectral differentiation capacity …

Quantitative comparison of frequency- domain and delay-and-sum optoacoustic image reconstruction including the effect of coherence factor weighting

Image reconstruction in optoacoustic imaging is often based on a delay-and-sum (DAS) or a frequency domain (FD) algorithm. In this study, we performed a comprehensive comparison of these two algorithms together with coherence factor (CF) weighting using phantom and in-vivo mouse data obtained with optoacoustic microscopy. For this purpose we developed an FD based definition …

Toward whole-brain in vivo optoacoustic angiography of rodents: modeling and experimental observations.

Cerebrovascular imaging of rodents is one of the trending applications of optoacoustics aimed at studying brain activity and pathology. Imaging of deep brain structures is often hindered by sub-optimal arrangement of the light delivery and acoustic detection systems. In our work we revisit the physics behind opto-acoustic signal generation for theoretical evaluation of optimal laser …

Quantitative techniques for extraction of blood oxygenation from multispectral optoacoustic

We report on the comparison of two approaches to the reconstruction of oxygen saturation (StO2) within blood vessels from multispectral optoacoustic (OA) measurements. The spatially-resolving approach is based on determination of the optical absorption coefficient µa from OA signal amplitudes, while the calibration-free approach is based on evaluation of the effective optical attenuation coefficient µeff derived from the in-depth …

Towards Bimodal Optical Monitoring of Photodynamic Therapy with Targeted Nanoconstructs: A Phantom Study

Increase of the efficiency of photodynamic therapy (PDT) requires the development of advanced protocols employing both novel photosensitizer (PS) carriers and aids for online monitoring. Nanoconstructs may be comprised of a photosensitizer, chemotherapy drugs, or inhibitors of molecular pathways that support cancer growth. In this paper, we analyze the efficiency of a bimodal approach involving …

Raster-scan optoacoustic angiography of blood vessel development in colon cancer models

Raster-scan optoacoustic angiography at 532 nm wavelength with 50 μm lateral resolution at 2 mm diagnostic depth was used for quantitative characterization of neoangiogenesis in colon cancer models. Two tumor models of human colon adenocarcinoma (HT-29) and murine colon carcinoma (CT26) different in their histology and vascularization were compared. Tumors of both origins showed an inhomogeneous distribution of areas with high and low vascularization. Rapidly growing CT26 …

Combination of virtual point detector concept and fluence compensation in acoustic resolution photoacoustic microscopy

We propose a hybrid approach to image enhancement in acoustic resolution photoacoustic microscopy. The developed technique is based on compensation for nonuniform spatial sensitivity of the optoacoustic (OA) system in both optical and acoustic domains. Spatial distribution of optical fluence is derived from full three-dimensional Monte Carlo simulations accounting for conical geometry of tissue laser …

Wideband linear detector arrays for optoacoustic imaging based on polyvinylidene difluoride

We provide direct experimental comparison of the optoacoustic imaging performance of two different 64-element linear detector array (LDA) units based on polyvinylidene difluoride (PVDF) films. The first LDA unit was based on traditional flexible circuit (FC) technology and consisted of an FC glued to the nonmetalized signal surface of a 28-μm-thick PVDF film providing 300  /  80-μm …

Raster-scan optoacoustic angiography reveals 3D microcirculatory changes during cuffed occlusion

Acoustic resolution photoacoustic microscopy at the optical wavelength of 532 nm was used to investigate the functional reaction of blood vessels of healthy human skin during cuffed venous occlusion. The high bandwidth of the polyvinilidene difluoride detector provided the opportunity for raster-scan optoacoustic angiography of both the superficial and deep plexuses at the high resolution of …

Fluence compensation in raster-scan optoacoustic angiography

Modern optical imaging techniques demonstrate significant potential for high resolution in vivoangiography. Optoacoustic angiography benefits from higher imaging depth as compared to pure optical modalities. However, strong attenuation of optoacoustic signal with depth provides serious challenges for adequate 3D vessel net mapping, and proper compensation for fluence distribution within biotissues is required. We report on the novel approach allowing …