Optoacoustic mesoscopy (OAM) retrieves anatomical and functional contrast in vivo at depths not resolvable with optical microscopy. Recent progress on reconstruction algorithms have further advanced its imaging performance to provide high lateral resolution ultimately limited by acoustic diffraction. In this work, a new broadband model-based OAM (MB-OAM) framework efficiently exploiting scanning symmetries for an enhanced …
Category: Publications
Sensitive ultrawideband transparent PVDF-ITO ultrasound detector for optoacoustic microscopy
An ultrasound detection scheme based on a transparent polyvinylidene-fluoride indium-tin-oxide (PVDF-ITO) piezoelectric film is developed for ultrawideband sensitive detection of optoacoustic (OA) signals down to a noise equivalent pressure (NEP) of 8.4 Pa over an effective detection bandwidth extending beyond 30 MHz. The high signal-to-noise ratio and low noise performance are facilitated by employing a two-stage amplifier …
In vivo monitoring of vascularization and oxygenation of tumor xenografts using optoacoustic microscopy and diffuse optical spectroscopy
The research is devoted to comparison of the blood vessel structure and the oxygen state of three xenografts: SN-12C, HCT-116 and Colo320. Differences in the vessel formation and the level of xygenation are revealed by optoacoustic (OA) microscopy and diffuse optical spectroscopy (DOS) espectively. The Colo320 tumor is characterized by the highest values of vessel …
Enhancing optoacoustic mesoscopy through calibration-based
iterative reconstruction
Optoacoustic mesoscopy combines rich optical absorption contrast with high spatial resolution at tissue depths beyond reach for microscopic techniques employing focused light excitation. The mesoscopic imaging performance is commonly hindered by the use of inaccurate delay-and-sum reconstruction approaches and idealized modeling assumptions. In principle, image reconstruction performance could be enhanced by simulating the optoacoustic signal generation, propagation, …
Noninvasive optoacoustic microangiography reveals dose and size dependency of radiation-induced deep tumor vasculature remodeling
Tumor microvascular responses may provide a sensitive readout indicative of radiation therapy efficacy, its time course and dose dependencies. However, direct high-resolution observation and longitudinal monitoring of large-scale microvascular remodeling in deep tissues remained challenging with the conventional microscopy approaches. We report on a non-invasive longitudinal study of morphological and functional neovascular responses by means …
Optoacoustic Sensing of Surfactant Crude Oil in Thermal Relaxation and Nonlinear Regimes
We propose a laser optoacoustic method for the complex characterization of crude oil pollution of the water surface by the thickness of the layer, the speed of sound, the coefficient of optical absorption, and the temperature dependence of the Grüneisen parameter. Using a 532 nm pulsed laser and a 1–100 MHz ultra-wideband ultrasonic antenna, we …
Broadband (100 kHz – 100 MHz) ultrasound PVDF detectors for raster-scan optoacoustic angiography with acoustic resolution
Spherical ultrasonic antennas are used in raster-scan optoacoustic (OA) angiography to record broadband signals generated by haemoglobin molecules in blood when they absorb pulsed optical radiation. Depending on the size of haemoglobin-containing structures, the characteristic frequencies of OA signals can vary quite significantly, ranging from hundreds of kilohertz to hundreds of megahertz. Meanwhile, the bandwidth …
Volumetric quantification of skin microcirculation disturbance induced by local compression
We report on the estimation of blood content and vessel volume fraction changes in the microcirculatory bed of human skin under controlled mechanical compression using 3-dimensional optoacoustic (OA) angiography. A consecutive decrease in the fraction of blood vessels and skin blood content as a result of an increase in pressure from 0 to 72 mmHg …
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 …
