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Stanislav Emelianov - One of the best experts on this subject based on the ideXlab platform.

  • Photoacoustic Imaging for cancer detection and staging
    Current Molecular Imaging (Discontinued), 2013
    Co-Authors: Mohammad Mehrmohammadi, Soon Joon Yoon, Douglas Yeager, Stanislav Emelianov
    Abstract:

    Cancer is one of the leading causes of death in the world. Diagnosing a cancer at its early stages of development can decrease the mortality rate significantly and reduce healthcare costs. Over the past two decades, Photoacoustic Imaging has seen steady growth and has demonstrated notable capabilities to detect cancerous cells and stage cancer. Furthermore, Photoacoustic Imaging combined with ultrasound Imaging and augmented with molecular targeted contrast agents is capable of Imaging cancer at the cellular and molecular level, thus opening diverse opportunities to improve diagnosis of tumors, detect circulating tumor cells and identify metastatic lymph nodes. In this paper we introduce the principles of Photoacoustic Imaging, and review recent developments in Photoacoustic Imagingas an emerging Imaging modality for cancer diagnosis and staging.

  • noninvasive detection of intimal xanthoma using combined ultrasound strain rate and Photoacoustic Imaging
    Ultrasonics, 2012
    Co-Authors: Iulia M Graf, Richard W Smalling, Seungsoo Kim, Bo Wang, Stanislav Emelianov
    Abstract:

    Abstract Background and motivation The structure, composition and mechanics of carotid artery are good indicators of early progressive atherosclerotic lesions. The combination of three Imaging modalities (ultrasound, strain rate and Photoacoustic Imaging) which could provide corroborative information about the named arterial properties could enhance the characterization of intimal xanthoma. Methods The experiments were performed using a New Zealand white rabbit model of atherosclerosis. The aorta excised from an atherosclerotic rabbit was scanned ex vivo using the three Imaging techniques: (1) ultrasound Imaging of the longitudinal section: standard ultrasound B-mode (74 Hz frame rate); (2) strain rate Imaging: the artery was flushed with blood and a 1.5 Hz physiologic pulsation was induced, while the ultrasound data were recorded at higher frame rate (296 Hz); (3) Photoacoustic Imaging: the artery was irradiated with nanosecond pulsed laser light of low fluence in the 1210–1230 nm wavelength range and the Photoacoustic data was recorded at 10 Hz frame rate. Post processing algorithms based on cross-correlation and optical absorption variation were implemented to derive strain rate and spectroscopic Photoacoustic images, respectively. Results Based on the spatio-temporal variation in displacement of different regions within the arterial wall, strain rate Imaging reveals differences in tissue mechanical properties. Additionally, spectroscopic Photoacoustic Imaging can spatially resolve the optical absorption properties of arterial tissue and identify the location of lipid pools. Conclusions The study demonstrates that ultrasound, strain rate and Photoacoustic Imaging can be used to simultaneously evaluate the structure, the mechanics and the composition of atherosclerotic lesions to improve the assessment of plaque vulnerability.

  • biomedical applications of Photoacoustic Imaging with exogenous contrast agents
    Annals of Biomedical Engineering, 2012
    Co-Authors: Geoffrey P Luke, Doug Yeager, Stanislav Emelianov
    Abstract:

    Photoacoustic Imaging is a biomedical Imaging modality that provides functional information, and, with the help of exogenous contrast agents, cellular and molecular signatures of tissue. In this article, we review the biomedical applications of Photoacoustic Imaging assisted with exogenous contrast agents. Dyes, noble metal nanoparticles, and other constructs are contrast agents which absorb strongly in the near-infrared band of the optical spectrum and generate strong Photoacoustic response. These contrast agents, which can be specifically targeted to molecules or cells, have been coupled with Photoacoustic Imaging for preclinical and clinical applications ranging from detection of cancer cells, sentinel lymph nodes, and micrometastasis to angiogenesis to characterization of atherosclerotic plaques. Multi-functional agents have also been developed, which can carry drugs or simultaneously provide contrast in multiple Imaging modalities. Furthermore, contrast agents were used to guide and monitor the therapeutic procedures. Overall, Photoacoustic Imaging shows significant promise in its ability to assist in diagnosis, therapy planning, and monitoring of treatment outcome for cancer, cardiovascular disease, and other pathologies.

  • Photoacoustic Imaging in cancer detection diagnosis and treatment guidance
    Trends in Biotechnology, 2011
    Co-Authors: Srivalleesha Mallidi, Geoffrey P Luke, Stanislav Emelianov
    Abstract:

    Imaging modalities play an important role in the clinical management of cancer, including screening, diagnosis, treatment planning and therapy monitoring. Owing to increased research efforts during the past two decades, Photoacoustic Imaging (a non-ionizing, noninvasive technique capable of visualizing optical absorption properties of tissue at reasonable depth, with the spatial resolution of ultrasound) has emerged. Ultrasound-guided Photoacoustics is noted for its ability to provide in vivo morphological and functional information about the tumor within the surrounding tissue. With the recent advent of targeted contrast agents, Photoacoustics is now also capable of in vivo molecular Imaging, thus facilitating further molecular and cellular characterization of cancer. This review examines the role of Photoacoustics and Photoacoustic-augmented Imaging techniques in comprehensive cancer detection, diagnosis and treatment guidance.

  • methodical study on plaque characterization using integrated vascular ultrasound strain and spectroscopic Photoacoustic Imaging
    Proceedings of SPIE, 2011
    Co-Authors: Iulia M Graf, Doug Yeager, James Amirian, Richard W Smalling, Stanislav Emelianov
    Abstract:

    Carotid atherosclerosis has been identified as a potential risk factor for cerebrovascular events, but information about its direct effect on the risk of recurrent stroke is limited due to incomplete diagnosis. The combination of vascular ultrasound, strain rate and spectroscopic Photoacoustics could improve the timely diagnosis of plaque status and risk of rupturing. Current ultrasound techniques can noninvasively image the anatomy of carotid arteries. The spatio-temporal variation in displacement of different regions within the arterial wall can be derived from ultrasound radio frequency data; therefore an ultrasound based strain rate Imaging modality can be used to reveal changes in arterial mechanical properties. Additionally, spectroscopic Photoacoustic Imaging can provide information on the optical absorption properties of arterial tissue and it can be used to identify the location of specific tissue components, such as lipid pools. An Imaging technique combining ultrasound, strain rate and spectroscopic Photoacoustics was tested on an excised atherosclerotic rabbit aorta. The ultrasound image illustrates inhomogeneities in arterial wall thickness, the strain rate indicates the arterial segment with reduced elasticity and the spectroscopic Photoacoustic image illustrates the accumulation of lipids. The results demonstrated that ultrasound, strain rate and spectroscopic Photoacoustic Imaging are complementary. Thus the integration of the three Imaging modalities advances the characterization of atherosclerotic plaques.

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

  • in vivo quantitative Imaging of tumor ph by nanosonophore assisted multispectral Photoacoustic Imaging
    Nature Communications, 2017
    Co-Authors: Chang H Lee, Raoul Kopelman, Xueding Wang
    Abstract:

    Changes of physiological pH are correlated with several pathologies, therefore the development of more effective medical pH Imaging methods is of paramount importance. Here, we report on an in vivo pH mapping nanotechnology. This subsurface chemical Imaging is based on tumor-targeted, pH sensing nanoprobes and multi-wavelength Photoacoustic Imaging (PAI). The nanotechnology consists of an optical pH indicator, SNARF-5F, 5-(and-6)-Carboxylic Acid, encapsulated into polyacrylamide nanoparticles with surface modification for tumor targeting. Facilitated by multi-wavelength PAI plus a spectral unmixing technique, the accuracy of pH measurement inside the biological environment is not susceptible to the background optical absorption of biomolecules, i.e., hemoglobins. As a result, both the pH levels and the hemodynamic properties across the entire tumor can be quantitatively evaluated with high sensitivity and high spatial resolution in in vivo cancer models. The Imaging technology reported here holds the potential for both research on and clinical management of a variety of cancers. Background optical absorption of several biomolecules impedes an effective in vivo pH Imaging in tumors. Here, the authors developed a visible light-based in vivo pH mapping method by coupling Photoacoustic Imaging and pH-responsive modified nanoparticles that selectively target tumor cells.

  • frequency domain analysis of Photoacoustic Imaging data from prostate adenocarcinoma tumors in a murine model
    Ultrasound in Medicine and Biology, 2011
    Co-Authors: Ronald E Kumon, Cheri X Deng, Xueding Wang
    Abstract:

    Photoacoustic Imaging is an emerging technique for anatomical and functional sub-surface Imaging but previous studies have predominantly focused on time-domain analysis. In this study, frequency-domain analysis of the radio-frequency signals from Photoacoustic Imaging was performed to generate quantitative parameters for tissue characterization. To account for the response of the Imaging system, the Photoacoustic spectra were calibrated by dividing the Photoacoustic spectra (radio-frequency ultrasound spectra resulting from laser excitation) from tissue by the Photoacoustic spectrum of a point absorber excited under the same conditions. The resulting quasi-linear Photoacoustic spectra were fit by linear regression and midband fit, slope and intercept were computed from the best-fit line. These Photoacoustic spectral parameters were compared between the region-of-interests (ROIs) representing prostate adenocarcinoma tumors and adjacent normal flank tissue in a murine model. The mean midband fit and intercept in the ROIs showed significant differences between cancerous and noncancerous regions. These initial results suggest that such frequency-domain analysis can provide a quantitative method for tumor tissue characterization using Photoacoustic Imaging in vivo.

  • frequency domain analysis of Photoacoustic Imaging data from prostate adenocarcinoma tumors in a murine model
    Ultrasound in Medicine and Biology, 2011
    Co-Authors: Ronald E Kumon, Cheri X Deng, Xueding Wang
    Abstract:

    Abstract Photoacoustic Imaging is an emerging technique for anatomical and functional sub-surface Imaging but previous studies have predominantly focused on time-domain analysis. In this study, frequency-domain analysis of the radio-frequency signals from Photoacoustic Imaging was performed to generate quantitative parameters for tissue characterization. To account for the response of the Imaging system, the Photoacoustic spectra were calibrated by dividing the Photoacoustic spectra (radio-frequency ultrasound spectra resulting from laser excitation) from tissue by the Photoacoustic spectrum of a point absorber excited under the same conditions. The resulting quasi-linear Photoacoustic spectra were fit by linear regression and midband fit, slope and intercept were computed from the best-fit line. These Photoacoustic spectral parameters were compared between the region-of-interests (ROIs) representing prostate adenocarcinoma tumors and adjacent normal flank tissue in a murine model. The mean midband fit and intercept in the ROIs showed significant differences between cancerous and noncancerous regions. These initial results suggest that such frequency-domain analysis can provide a quantitative method for tumor tissue characterization using Photoacoustic Imaging in vivo . (E-mail: cxdeng@umich.edu and xdwang@umich.edu )

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

  • optical drug monitoring Photoacoustic Imaging of nanosensors to monitor therapeutic lithium in vivo
    ACS Nano, 2015
    Co-Authors: Kevin J Cash, Lihong V Wang, Jun Xia, Heather A Clark
    Abstract:

    Personalized medicine could revolutionize how primary care physicians treat chronic disease and how researchers study fundamental biological questions. To realize this goal, we need to develop more robust, modular tools and Imaging approaches for in vivo monitoring of analytes. In this report, we demonstrate that synthetic nanosensors can measure physiologic parameters with Photoacoustic contrast, and we apply that platform to continuously track lithium levels in vivo. Photoacoustic Imaging achieves Imaging depths that are unattainable with fluorescence or multiphoton microscopy. We validated the Photoacoustic results that illustrate the superior Imaging depth and quality of Photoacoustic Imaging with optical measurements. This powerful combination of techniques will unlock the ability to measure analyte changes in deep tissue and will open up Photoacoustic Imaging as a diagnostic tool for continuous physiological tracking of a wide range of analytes.

  • saturation effect in functional Photoacoustic Imaging
    Journal of Biomedical Optics, 2010
    Co-Authors: Jing Wang, Lihong V Wang, Tan Liu, Shuliang Jiao, Ruimin Chen, Qifa Zhou, Kirk K Shung, Hao Zhang
    Abstract:

    We investigate the saturation effect, which describes the violation of the linearity between the measured Photoacoustic ampli- tude and the object's optical absorption coefficient in functional pho- toacoustic Imaging when the optical absorption in the object in- creases. We model the optical energy deposition and Photoacoustic signal generation and detection in a semi-infinite optical absorbing object. Experiments are carried out by measuring Photoacoustic sig- nals generated from an ink-filled plastic tube. The saturation effect is studied by varying the optical absorption coefficient in the model and the ink concentration in the Photoacoustic experiments. By changing the center frequency of the ultrasonic detector, the requirement to minimize the saturation effect in functional Photoacoustic Imaging is established. © 2010 Society of Photo-Optical Instrumentation Engineers. DOI: 10.1117/1.3333549

  • high speed dynamic 3d Photoacoustic Imaging of sentinel lymph node in a murine model using an ultrasound array
    Medical Physics, 2009
    Co-Authors: Liang Song, Konstantin Maslov, Kirk K Shung, Lihong V Wang
    Abstract:

    Noninvasive Photoacoustic sentinel lymph node (SLN) mapping with high spatial resolution has the potential to improve the false negative rate and eliminate the use of radioactive tracers in SLN identification. In addition, the demonstrated high spatial resolution may enable physicians to replace SLN biopsy with fine needle aspiration biopsy, and thus reduce the risk of associated morbidity. The primary goal of this study is to demonstrate the feasibility of high-speed 3D Photoacoustic Imaging of the uptake and clearance dynamics of Evans blue dye in SLNs. The Photoacoustic Imaging system was developed with a 30MHz ultrasound array and a kHz repetition rate laser system. It acquires one 3D Photoacousticimage of 166 B-scan frames in 1s, with axial, lateral, and elevational resolutions of 25, 70, and 200μm, respectively. With optic-fiber based light delivery, the entire system is compact and is convenient to use. Upon injection of Evans blue, a blue dye currently used in clinical SLN biopsy, SLNs in mice and rats were accurately and noninvasively mapped in vivo using our Imaging system. In our experiments, the SLNs were found to be located at ∼0.65mm below the skin surface in mice and ∼1.2mm in rats. In some cases, lymph vessels and lymphatic valves were also imaged. The dye dynamics—accumulation and clearance—in SLNs were quantitatively monitored by sequential 3D Imaging with temporal resolution of as high as ∼6s. The demonstrated capability suggests that high-speed 3D Photoacoustic Imaging should facilitate the understanding of the dynamics of various dyes in SLNs and potentially help identify SLNs with high accuracy.

  • 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 Imaging of biological tissue with intensity modulated continuous wave laser
    Journal of Biomedical Optics, 2008
    Co-Authors: Konstantin Maslov, Lihong V Wang
    Abstract:

    We build a Photoacoustic Imaging system using an intensity-modulated continuous-wave laser source, which is an inexpensive, compact, and durable 120-mW laser diode. The goal is to significantly reduce the costs and sizes of Photoacoustic Imaging systems. By using a bowl-shaped piezoelectric transducer, whose numerical aperture is 0.85 and resonance frequency is 2.45 MHz, we image biological tissues with a lateral resolution of 0.45 mm, an axial resolution of 1 mm, and an SNR as high as 43 dB.

Paul C Beard - One of the best experts on this subject based on the ideXlab platform.

  • contrast agents for molecular Photoacoustic Imaging
    Nature Methods, 2016
    Co-Authors: Judith Weber, Paul C Beard, Sarah E. Bohndiek
    Abstract:

    This Review covers genetically encoded and exogenous contrast agents for Photoacoustic Imaging and offers guidance for choosing optimal probes for biological applications on the basis of photophysical properties, targeting and performance.

  • contrast agents for molecular Photoacoustic Imaging
    Nature Methods, 2016
    Co-Authors: Judith Weber, Paul C Beard, Sarah E. Bohndiek
    Abstract:

    Photoacoustic Imaging (PAI) is an emerging tool that bridges the traditional depth limits of ballistic optical Imaging and the resolution limits of diffuse optical Imaging. Using the acoustic waves generated in response to the absorption of pulsed laser light, it provides noninvasive images of absorbed optical energy density at depths of several centimeters with a resolution of ∼100 μm. This versatile and scalable Imaging modality has now shown potential for molecular Imaging, which enables visualization of biological processes with systemically introduced contrast agents. Understanding the relative merits of the vast range of contrast agents available, from small-molecule dyes to gold and carbon nanostructures to liposome encapsulations, is a considerable challenge. Here we critically review the physical, chemical and biochemical characteristics of the existing Photoacoustic contrast agents, highlighting key applications and present challenges for molecular PAI.

  • characterisation of a phantom for multiwavelength quantitative Photoacoustic Imaging
    Physics in Medicine and Biology, 2016
    Co-Authors: Martina Fonseca, Paul C Beard, Bajram Zeqiri, Ben Cox
    Abstract:

    Quantitative Photoacoustic Imaging (qPAI) has the potential to provide high- resolution in vivo images of chromophore concentration, which may be indicative of tissue function and pathology. Many strategies have been proposed recently for extracting quantitative information, but many have not been experimentally verified. Experimental phantom-based validation studies can be used to test the robustness and accuracy of such algorithms in order to ensure reliable in vivo application is possible. The phantoms used in such studies must have well-characterised optical and acoustic properties similar to tissue, and be versatile and stable. Polyvinyl chloride plastisol (PVCP) has been suggested as a phantom for quality control and system evaluation. By characterising its multiwavelength optical properties, broadband acoustic properties and thermoelastic behaviour, this paper examines its potential as a phantom for qPAI studies too. PVCP's acoustic properties were assessed for various formulations, as well as its intrinsic optical absorption, and scattering with added TiO2, over a range of wavelengths from 400-2000 nm. To change the absorption coefficient, pigment-based chromophores that are stable during the phantom fabrication process, were used. These yielded unique spectra analogous to tissue chromophores and linear with concentration. At the high peak powers typically used in Photoacoustic Imaging, nonlinear optical absorption was observed. The Gruneisen parameter was measured to be [Formula: see text]  =  1.01  ±  0.05, larger than typically found in tissue, though useful for increased PA signal. Single and multiwavelength 3D PA Imaging of various fabricated PVCP phantoms were demonstrated.

  • in vivo high resolution 3d Photoacoustic Imaging of superficial vascular anatomy
    Physics in Medicine and Biology, 2009
    Co-Authors: Edward Z Zhang, Jan Laufer, R B Pedley, Paul C Beard
    Abstract:

    The application of a Photoacoustic Imaging instrument based upon a Fabry– Perot polymer film ultrasound sensor to Imaging the superficial vasculature is described. This approach provides a backward mode-sensing configuration that has the potential to overcome the limitations of current piezoelectric based detection systems used in superficial Photoacoustic Imaging. The system has been evaluated by obtaining non-invasive images of the vasculature in human and mouse skin as well as mouse models of human colorectal tumours. These studies showed that the system can provide high-resolution 3D images of vascular structures to depths of up to 5 mm. It is considered that this type of instrument may find a role in the clinical assessment of conditions characterized by changes in the vasculature such as skin tumours and superficial soft tissue damage due to burns, wounds or ulceration. It may also find application in the characterization of small animal cancer models where it is important to follow the tumour vasculature over time in order to study its development and/or response to therapy. M This article features online multimedia enhancements (Some figures in this article are in colour only in the electronic version)

  • quantitative Photoacoustic Imaging fitting a model of light transport to the initial pressure distribution
    Biomedical optics, 2005
    Co-Authors: B T Cox, Simon R Arridge, Kornel P Kostli, Paul C Beard
    Abstract:

    Photoacoustic Imaging, which generates a map of the initial acoustic pressure distribution generated by a short laser pulse, has been demonstrated by several authors. Quantitative Photoacoustic Imaging takes this one stage further to produce a map of the distribution of an optical property of the tissue, in this case absorption, which can then be related to a physiological parameter. In this technique, the initial pressure distribution is assumed to be proportional to the absorbed laser energy density. A model of light transport in scattering media is then used to estimate the distribution of optical properties that would result in such a pattern of absorbed energy. The light model used a finite element implementation of the diffusion equation (with the delta-E(3) approximation included to improve the accuracy at short distances inside the scattering medium). An algorithm which applies this model iteratively and converges on a quantitative estimate of the optical absorption distribution is described. 2D examples using simulated data (initial pressure maps) with and without noise are shown to converge quickly and accurately.

Liang Song - One of the best experts on this subject based on the ideXlab platform.

  • ultrasmall cu2 xs nanodots for highly efficient Photoacoustic Imaging guided photothermal therapy
    Small, 2015
    Co-Authors: Juan Mou, Chengbo Liu, Liang Song, Jin Wang, Kun Zhang, Yu Chen, Jianlin Shi, Hangrong Chen
    Abstract:

    Monodisperse, ultrasmall (<5 nm) Cu(2-x)S nanodots (u-Cu(2-x)S NDs) with significantly strong near-infrared absorption and conversion are successfully demonstrated for effective deep-tissue Photoacoustic Imaging-guided photothermal therapy both in vitro and in vivo. Owing to ultrasmall nanoparticle size and high water dispersibility as well as long stability, such nanodots possess a prolonged circulation in blood and good passive accumulation within tumors through the enhanced permeability and retention effect. These u-Cu(2-x)S NDs have negligible side effects to both blood and normal tissues according to in vivo toxicity evaluations for up to 3 months, showing excellent hemo/histocompatibility. Furthermore, these u-Cu(2-x)S NDs can be thoroughly cleared through feces and urine within 5 days, showing high biosafety for further potential clinical translation. This novel Photoacoustic Imaging-guided photothermal therapy based on u-Cu(2-x)S NDs composed of a single component shows great prospects as a multifunctional nanoplatform with integration and multifunction for cancer diagnosis and therapy.

  • Protein-assisted fabrication of nano-reduced graphene oxide for combined in vivo Photoacoustic Imaging and photothermal therapy.
    Biomaterials, 2013
    Co-Authors: Zonghai Sheng, Mingbin Zheng, Ping Gong, Guanhui Gao, Liang Song, Jiaxiang Zheng, Pengfei Zhang
    Abstract:

    Theranostic agents are attracting a great deal of attention in personalized medicine. Here, we developed a protein-based, facile method for fabrication of nanosized, reduced graphene oxide (nano-rGO) with high stability and low cytotoxicity. We constructed highly integrated Photoacoustic/ultrasonic dual-modality Imaging and photothermal therapy platforms, and further demonstrated that the prepared nano-rGO can be used as ready-to-use theranostic agents for both Photoacoustic Imaging and photothermal therapy without further surface modification. Intravenous administration of nano-rGO in tumor-bearing mice showed rapid and significant Photoacoustic signal enhancement in the tumor region, indicating its excellence for passive targeting and Photoacoustic Imaging. Meanwhile, using a continuous-wave near-infrared laser, cancer cells in vivo were efficiently ablated, due to the photothermal effect of nano-rGO. The results suggest that the nano-rGO with protein-assisted fabrication was well suited for Photoacoustic Imaging and photothermal therapy of tumor, which is promising for theranostic nanomedicine.

  • high speed dynamic 3d Photoacoustic Imaging of sentinel lymph node in a murine model using an ultrasound array
    Medical Physics, 2009
    Co-Authors: Liang Song, Konstantin Maslov, Kirk K Shung, Lihong V Wang
    Abstract:

    Noninvasive Photoacoustic sentinel lymph node (SLN) mapping with high spatial resolution has the potential to improve the false negative rate and eliminate the use of radioactive tracers in SLN identification. In addition, the demonstrated high spatial resolution may enable physicians to replace SLN biopsy with fine needle aspiration biopsy, and thus reduce the risk of associated morbidity. The primary goal of this study is to demonstrate the feasibility of high-speed 3D Photoacoustic Imaging of the uptake and clearance dynamics of Evans blue dye in SLNs. The Photoacoustic Imaging system was developed with a 30MHz ultrasound array and a kHz repetition rate laser system. It acquires one 3D Photoacousticimage of 166 B-scan frames in 1s, with axial, lateral, and elevational resolutions of 25, 70, and 200μm, respectively. With optic-fiber based light delivery, the entire system is compact and is convenient to use. Upon injection of Evans blue, a blue dye currently used in clinical SLN biopsy, SLNs in mice and rats were accurately and noninvasively mapped in vivo using our Imaging system. In our experiments, the SLNs were found to be located at ∼0.65mm below the skin surface in mice and ∼1.2mm in rats. In some cases, lymph vessels and lymphatic valves were also imaged. The dye dynamics—accumulation and clearance—in SLNs were quantitatively monitored by sequential 3D Imaging with temporal resolution of as high as ∼6s. The demonstrated capability suggests that high-speed 3D Photoacoustic Imaging should facilitate the understanding of the dynamics of various dyes in SLNs and potentially help identify SLNs with high accuracy.