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Lihong V Wang - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear photoacoustic spectroscopy of hemoglobin
    Applied Physics Letters, 2015
    Co-Authors: Amos Danielli, Konstantin Maslov, Christopher P Favazza, Jun Xia, Lihong V Wang
    Abstract:

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of Photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.

  • noise equivalent sensitivity of Photoacoustics
    Journal of Biomedical Optics, 2013
    Co-Authors: Amy M Winkler, Konstantin Maslov, Lihong V Wang
    Abstract:

    The fundamental limitations of photoacoustic microscopy for detecting optically absorbing molecules are investigated both theoretically and experimentally. We experimentally demonstrate noise-equivalent detection sensitivities of 160,000 methylene blue molecules (270 zeptomol or 2.7×10^(−19) mol) and 86,000 oxygenated hemoglobin molecules (140 zeptomol) using narrowband continuous-wave Photoacoustics. The ultimate sensitivity of Photoacoustics is fundamentally limited by thermal noise, which can present in the acoustic detection system as well as in the medium itself. Under the optimized conditions described herein and using commercially available detectors, photoacoustic microscopy can detect as few as 100s of oxygenated hemoglobin molecules. Realizable improvements to the detector may enable single molecule detection of select molecules.

  • photoacoustic imaging and characterization of the microvasculature
    Journal of Biomedical Optics, 2010
    Co-Authors: Lihong V Wang
    Abstract:

    Photoacoustic (optoacoustic) tomography, combining optical absorption contrast and highly scalable spatial resolution (from micrometer optical resolution to millimeter acoustic resolution), has broken through the fundamental penetration limit of optical ballistic imaging modalities-including confocal microscopy, two-photon microscopy, and optical coherence tomography-and has achieved high spatial resolution at depths down to the diffusive regime. Optical absorption contrast is highly desirable for microvascular imaging and characterization because of the presence of endogenous strongly light-absorbing hemoglobin. We focus on the current state of microvascular imaging and characterization based on Photoacoustics. We first review the three major embodiments of photoacoustic tomography: microscopy, computed tomography, and endoscopy. We then discuss the methods used to characterize important functional parameters, such as total hemoglobin concentration, hemoglobin oxygen saturation, and blood flow. Next, we highlight a few representative applications in microvascular-related physiological and pathophysiological research, including hemodynamic monitoring, chronic imaging, tumor-vascular interaction, and neurovascular coupling. Finally, several potential technical advances toward clinical applications are suggested, and a few technical challenges in contrast enhancement and fluence compensation are summarized.

  • photoacoustic imaging and spectroscopy
    Journal of Biomedical Optics, 2009
    Co-Authors: Lihong V Wang
    Abstract:

    Photoacoustics Photoacoustic Monopole Radiation: Waves from Objects with Symmetry in One, Two, and Three Dimensions, Gerald. J. Diebold Photoacoustic Doppler Effect and Flow Sensing, Hui Fang and Lihong V. Wang Modeling Photoacoustic Propagation in Tissue Using k-Space Techniques, Ben Cox and Paul C. Beard Photoacoustic Image Reconstruction: Algorithm, Resolution, and View Universal Back-Projection Algorithm for Photoacoustic Tomography, Minghua Xu and Lihong V. Wang Analysis of Spatial Resolution in Photoacoustic Tomography, Minghua Xu and Lihong V. Wang Limited View Thermoacoustic Tomography, Yuan Xu, Lihong V. Wang, Gaik Ambartsoumian, and Peter Kuchment Photoacoustic Image Reconstruction: Mathematical Perspectives Recovering a Function from Its Spherical Mean Values in Two and Three Dimensions, David Finch and Rakesh On Reconstruction Formulas and Algorithms for the Thermoacoustic Tomography, Mark Agranovsky, Peter Kuchment, and Leonid Kunyansky Photoacoustic and Thermoacoustic Tomography: Consistency Conditions and the Partial Scan Problem, Sarah K. Patch Photoacoustic I Part mage Reconstruction: Advanced Algorithms Time Reversal in Photoacoustic or Thermoacoustic Tomography, Yuan Xu and Lihong V. Wang Quantitative Photoacoustic Imaging: Measurement of Absolute Chromophore Concentrations for Physiological and Molecular Imaging, Paul C. Beard, Jan G. Laufer, Ben Cox, and Simon R. Arridge Image Reconstruction in Optoacoustic Tomography Accounting for Frequency-Dependent Attenuation, Patrick La Riviere, Jin Zhang, and Mark A. Anastasio Half-Time Image Reconstruction in Photoacoustic Tomography, Mark A. Anastasio, Jin Zhang, Xiaochuan Pan, and Lihong V. Wang Adaptive and Robust Methods for Thermoacoustic and Photoacoustic Tomography, Bin Guo and Jian Li Ultrasonic Detectors for Photoacoustic Tomography Photoacoustic Imaging with a Double-Ring Sensor, Roy G.M. Kolkman, Ton G. van Leeuwen, and Wiendelt Steenbergen Photoacoustic Tomography Based on Ring-Shaped Virtual Point Ultrasonic Detector, Xinmai Yang and Lihong V. Wang 3D Photoacoustic Scanner Based on an Optical Ultrasound-Mapping System for Imaging Superficial Vascular Anatomy In Vivo, Paul C. Beard, Edward Z. Zhang, and Jan G. Laufer High-Frequency Optoacoustic Transducers for Ultrasonic and Photoacoustic Imaging, Shai Ashkenazi, Yang Hou, Sheng-Wen Huang, Takashi Buma, and Matt O'Donnell Interferometry-Based Optoacoustic Tomography, Hagyong Kihm, Stefan A. Carp, and Vasan Venugopalan Photoacoustic Tomography with Integrating Area and Line Detectors, Gunther Paltauf, Robert Nuster, Markus Haltmeier, and Peter Burgholzer Focused Scanning Photoacoustic Part Tomography with Laser Excitation Dark-Field Confocal Photoacoustic Microscopy, Hao F. Zhang, Konstantin Maslov, and Lihong V. Wang Deep-Penetrating Reflection-Mode Photoacoustic Imaging, Kwang Hyun Song and Lihong V. Wang Array-Based Photoacoustic Tomography with Laser Excitation Combined Ultrasound and Photoacoustic System for Real-Time High-Contrast Imaging Using a Linear Array Transducer, Michael Jaeger and Martin Frenz Fast Photoacoustic Imaging System Based on 320-Element Linear Transducer Array, Da Xing Design and Characterization of an Array-Based Photoacoustic Tomographic System for Small Animal Imaging, John Gamelin, Andres Aguirre, Anastasios Maurudis, Fei Huang, Diego Castillo, Lihong V. Wang, and Quing Zhu T hermoacoustic Tomography with Microwave Excitation Thermoacoustic Computed Tomography of the Breast, Robert A. Kruger Microwave-Induced Acoustic (Thermoacoustic) Tomography, Lihong V. Wang Functional and Molecular Photoacoustic Tomography Functional and Molecular Photoacoustic Tomography of Small-Animal Brains, Xueding Wang and Lihong V. Wang Photoacoustic Imaging of Gene Expression in Small Animals In Vivo, Roger J. Zemp, Li Li, and Lihong V. Wang Photoacoustic Tomography w Part ith Nanoparticles Gold and Silver Nanoparticles as Contrast Agents for Optoacoustic Tomography, Alexander A. Oraevsky Photoacoustic Flow Measurements with Gold Nanoparticles, Pai-Chi Li, Chen-Wei Wei, Sheng-Wen Huang, Chao-Kang Liao, and Churng-Ren Wang Photoacoustic Imaging and Therapy Utilizing Molecular Specific Plasmonic Nanoparticles, Stanislav Emelianov, Srivalleesha Mallidi, Timothy Larson, and Konstantin Sokolov Photoacoustic Tomography of Breasts, Joints, and Vessels Optoacoustic Tomography of the Breast, Alexander A. Oraevsky Photoacoustic Mammography with a Flat Detection Geometry, Srirang Manohar, Ton G. van Leeuwen, Joost M. Klaase, Frank M. van den Engh, and Wiendelt Steenbergen Photoacoustic Tomography: A New Imaging Technology for Inflammatory Arthritis, Xueding Wang, David L. Chamberland, Paul L. Carson, and J. Brian Fowlkes Intravascular Photoacoustic Imaging of Atherosclerosis, Shriram Sethuraman, Bo Wang, Richard Smalling, and Stanislav Emelianov Photoacoustic Depth Determination and Imaging of Port Wine Stain Birthmarks, John A. Viator, Roy G.M. Kolkman, and Wiendelt Steenbergen Multimodal Imaging Thermoacoustic Reconstruction in Acoustically Heterogeneous Media with the Aid of Ultrasound Tomography, Xing Jin and Lihong V. Wang Role of Photoacoustic and Ultrasound Imaging in Photothermal Therapy, Jignesh Shah, Suhyun Park, Salavat Aglyamov, and Stanislav Emelianov Index

  • Photoacoustic tomography and sensing in biomedicine
    Physics in Medicine and Biology, 2009
    Co-Authors: Changhui Li, Lihong V Wang
    Abstract:

    Photoacoustics has been broadly studied in biomedicine, for both human and small animal tissues. Photoacoustics uniquely combines the absorption contrast of light or radio frequency waves with ultrasound resolution. Moreover, it is non-ionizing and non-invasive, and is the fastest growing new biomedical method, with clinical applications on the way. This review provides a brief recap of recent developments in Photoacoustics in biomedicine, from basic principles to applications. The emphasized areas include the new imaging modalities, hybrid detection methods, photoacoustic contrast agents and the photoacoustic Doppler effect, as well as translational research topics.

J. D. Witt - One of the best experts on this subject based on the ideXlab platform.

  • chemical characterization of the dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
    Dental Materials, 1992
    Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. Witt
    Abstract:

    Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacture's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.

  • chemical characterization of the dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
    Dental Materials, 1992
    Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. Witt
    Abstract:

    Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacture's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.

Wiendelt Steenbergen - One of the best experts on this subject based on the ideXlab platform.

  • Tomographic Ultrasound and LED-Based Photoacoustic System for Preclinical Imaging.
    Sensors (Basel Switzerland), 2020
    Co-Authors: Kalloor Joseph Francis, Richell Booijink, Ruchi Bansal, Wiendelt Steenbergen
    Abstract:

    Small animals are widely used as disease models in medical research. Noninvasive imaging modalities with functional capability play an important role in studying the disease state and treatment progress. Photoacoustics, being a noninvasive and functional modality, has the potential for small-animal imaging. However, the conventional photoacoustic tomographic systems use pulsed lasers, making it expensive, bulky, and require long acquisition time. In this work, we propose the use of photoacoustic and ultrasound tomographic imaging with LEDs as the light source and acoustic detection using a linear transducer array. We have demonstrated full-view tomographic imaging of a euthanized mouse and a potential application in liver fibrosis research.

  • photoacoustic imaging of blood vessels with a pulsed laser diode. Lasers Med
    2016
    Co-Authors: Roy G. M. Kolkman, Wiendelt Steenbergen, Erwin Hondebrink, Frits F. M. De Mul
    Abstract:

    Abstract—We applied Photoacoustics for noninvasive two-dimensional imaging of blood vessels in vivo, using near infrared light. This study was undertaken to develop photoa-coustic tomography of tissue for the detection of embedded blood vessels using a newly developed piezoelectric double ring detector, featuring an extremely narrow aperture. Index Terms—Biomedical imaging, blood, photoacoustic effects, piezoelectric devices, tomography. I

  • Quantitative blood oxygen saturation imaging using combined Photoacoustics and acousto-optics
    Optics Letters, 2016
    Co-Authors: Altaf Hussain, Erwin Hondebrink, Wilhelmina Petersen, Jacob Staley, Wiendelt Steenbergen
    Abstract:

    In photoacoustic spectroscopy (PAS), wavelength dependent optical attenuation of biological tissue presents a challenge to measure the absolute oxygen saturation of hemoglobin (sO 2). Here, we employ the combination of Photoacoustics and acousto-optics (AO) at two optical wavelengths to achieve quantification, where AO serves as a sensor for the relative local fluence. We demonstrate that our method enables compensation of spatial as well as wavelength dependent fluence variations in PAS without a priori knowledge about the optical properties of the medium. The fluence compensated photoacoustic images at two excitation wavelengths are used to estimate the absolute oxygen saturation of blood in a spatially and spectroscopically heterogeneous phantom.

  • handheld probe integrating laser diode and ultrasound transducer array for ultrasound photoacoustic dual modality imaging
    Optics Express, 2014
    Co-Authors: Khalid Daoudi, Olivier Rabot, S Tisserand, Peter J. Brands, Andreas Kohl, P. J. Berg, Wiendelt Steenbergen
    Abstract:

    Ultrasound and Photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dual-modality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint

  • correcting photoacoustic signals for fluence variations using acousto optic modulation
    Optics Express, 2012
    Co-Authors: Khalid Daoudi, Erwin Hondebrink, Altaf Hussain, Wiendelt Steenbergen
    Abstract:

    We present a theoretical concept which may lead to quantitative photoacoustic mapping of chromophore concentrations. The approach supposes a technique capable of tagging light in a well-defined tagging volume at a specific location deep in the medium. We derive a formula that expresses the local absorption coefficient inside a medium in terms of noninvasively measured quantities and experimental parameters and we validate the theory using Monte Carlo simulations. Furthermore, we performed an experiment to basically validate the concept as a strategy to correct for fluence variations in Photoacoustics. In the experiment we exploit the possibility of acousto-optic modulation, using focused ultrasound, to tag photons. Results show that the variation in photoacoustic signals of absorbing insertions embedded at different depths in a phantom, caused by fluence variations of more than one order of magnitude, can be corrected for to an accuracy of 5%.

Paulette Spencer - One of the best experts on this subject based on the ideXlab platform.

  • chemical characterization of the dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
    Dental Materials, 1992
    Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. Witt
    Abstract:

    Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacture's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.

  • chemical characterization of the dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
    Dental Materials, 1992
    Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. Witt
    Abstract:

    Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacture's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.

Yuanjin Zheng - One of the best experts on this subject based on the ideXlab platform.

  • micro doppler photoacoustic effect and sensing by ultrasound radar
    IEEE Journal of Selected Topics in Quantum Electronics, 2016
    Co-Authors: Fei Gao, Xiaohua Feng, Yuanjin Zheng
    Abstract:

    In recent years, Photoacoustics have been studied for both anatomical and functional biomedical imaging. However, the physical interaction between photoacoustic-generated endogenous waves and an exogenously applied ultrasound wave is a largely unexplored area. Here, we report the initial results about the interaction of photoacoustic and external ultrasound waves leading to a micro-Doppler photoacoustic (mDPA) effect, which is experimentally observed and consistently modeled. It is based on a simultaneous excitation on the target with a pulsed laser and continuous wave (CW) ultrasound. The thermoelastically induced expansion will modulate the CW ultrasound and lead to transient Doppler frequency shift. The reported mDPA effect can be described as frequency modulation of the intense CW ultrasound carrier through photoacoustic vibrations. This technique may open the possibility to sensitively detect the photoacoustic vibration in deep optically and acoustically scattering medium, avoiding acoustic distortion that exists in state-of-the-art pulsed photoacoustic imaging systems.

  • photoacoustic resonance spectroscopy for biological tissue characterization
    Journal of Biomedical Optics, 2014
    Co-Authors: Fei Gao, Xiaohua Feng, Yuanjin Zheng, Clausdieter Ohl
    Abstract:

    By "listening to photons," Photoacoustics allows the probing of chromosomes in depth beyond the optical diffusion limit. Here we report the photoacoustic resonance effect induced by multiburst modulated laser illumination, which is theoretically modeled as a damped mass-string oscillator and a resistor-inductor-capacitor (RLC) circuit. Through sweeping the frequency of multiburst modulated laser, the photoacoustic resonance effect is observed experimentally on phantoms and porcine tissues. Experimental results demonstrate different spectra for each phantom and tissue sample to show significant potential for spectroscopic analysis, fusing optical absorption and mechanical vibration properties. Unique RLC circuit parameters are extracted to quanti- tatively characterize phantom and biological tissues. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10

  • photoacoustic resonance spectroscopy for biological tissue characterization
    Journal of Biomedical Optics, 2014
    Co-Authors: Xiaohua Feng, Yuanjin Zheng
    Abstract:

    By "listening to photons," Photoacoustics allows the probing of chromosomes in depth beyond the optical diffusion limit. Here we report the photoacoustic resonance effect induced by multiburst modulated laser illumination, which is theoretically modeled as a damped mass-string oscillator and a resistor-inductor-capacitor (RLC) circuit. Through sweeping the frequency of multiburst modulated laser, the photoacoustic resonance effect is observed experimentally on phantoms and porcine tissues. Experimental results demonstrate different spectra for each phantom and tissue sample to show significant potential for spectroscopic analysis, fusing optical absorption and mechanical vibration properties. Unique RLC circuit parameters are extracted to quanti- tatively characterize phantom and biological tissues. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10