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

  • Recent Advances in Photoacoustic Tomography
    'American Association for the Advancement of Science (AAAS)', 2021
    Co-Authors: Lihong V Wang
    Abstract:

    Photoacoustic Tomography (PAT) that integrates the molecular contrast of optical imaging with the high spatial resolution of ultrasound imaging in deep tissue has widespread applications in basic biological science, preclinical research, and clinical trials. Recently, tremendous progress has been made in PAT regarding technical innovations, preclinical applications, and clinical translations. Here, we selectively review the recent progresses and advances in PAT, including the development of advanced PAT systems for small-animal and human imaging, newly engineered optical probes for molecular imaging, broad-spectrum PAT for label-free imaging of biological tissues, high-throughput snapshot Photoacoustic topography, and integration of machine learning for image reconstruction and processing. We envision that PAT will have further technical developments and more impactful applications in biomedicine

  • Photoacoustic Tomography principles and advances
    Electromagn Waves (Camb), 2016
    Co-Authors: Jun Xia, Junjie Yao, Lihong V Wang
    Abstract:

    Photoacoustic Tomography (PAT) is an emerging imaging modality that shows great potential for preclinical research and clinical practice. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous chromophores, such as oxy-hemoglobin and deoxy-hemoglobin, or exogenous contrast agents, such as organic dyes and nanoparticles. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Over the past decade, the Photoacoustic technique has been evolving rapidly, leading to a variety of exciting discoveries and applications. This review covers the basic principles of PAT and its different implementations. Strengths of PAT are highlighted, along with the most recent imaging results.

  • a practical guide to Photoacoustic Tomography in the life sciences
    Nature Methods, 2016
    Co-Authors: Lihong V Wang, Junjie Yao
    Abstract:

    The life sciences can benefit greatly from imaging technologies that connect microscopic discoveries with macroscopic observations. One technology uniquely positioned to provide such benefits is Photoacoustic Tomography (PAT), a sensitive modality for imaging optical absorption contrast over a range of spatial scales at high speed. In PAT, endogenous contrast reveals a tissue's anatomical, functional, metabolic, and histologic properties, and exogenous contrast provides molecular and cellular specificity. The spatial scale of PAT covers organelles, cells, tissues, organs, and small animals. Consequently, PAT is complementary to other imaging modalities in contrast mechanism, penetration, spatial resolution, and temporal resolution. We review the fundamentals of PAT and provide practical guidelines for matching PAT systems with research needs. We also summarize the most promising biomedical applications of PAT, discuss related challenges, and envision PAT's potential to lead to further breakthroughs.

  • tutorial on Photoacoustic Tomography
    Journal of Biomedical Optics, 2016
    Co-Authors: Yong Zhou, Junjie Yao, Lihong V Wang
    Abstract:

    Photoacoustic Tomography (PAT) has become one of the fastest growing fields in biomedical optics. Unlike pure optical imaging, such as confocal microscopy and two-photon microscopy, PAT employs acoustic detection to image optical absorption contrast with high-resolution deep into scattering tissue. So far, PAT has been widely used for multiscale anatomical, functional, and molecular imaging of biological tissues. We focus on PAT’s basic principles, major implementations, imaging contrasts, and recent applications.

  • breakthroughs in photonics 2013 Photoacoustic Tomography in biomedicine
    IEEE Photonics Journal, 2014
    Co-Authors: Lihong V Wang
    Abstract:

    Photoacoustic Tomography (PAT) is one of the fastest growing biomedical imaging modalities in the last decade. Building on its high scalability and complementary imaging contrast to other mainstream modalities, PAT has gained substantial momentum in both preclinical and clinical studies. In 2013, PAT has grown markedly in both its technological capabilities and biomedical applications. In particular, breakthroughs have been made in super-resolution imaging, deep blood flow measurement, small animal resting state brain mapping, video rate functional human imaging, and human breast imaging. These breakthroughs have either successfully solved long-standing technical issues in PAT or significantly enhanced its imaging capability. This review will summarize state-of-the-art developments in PAT and highlight a few representative achievements of the year 2013.

Huabei Jiang - One of the best experts on this subject based on the ideXlab platform.

  • 4 d Photoacoustic Tomography
    Scientific Reports, 2013
    Co-Authors: Liangzhong Xiang, Bo Wang, Huabei Jiang
    Abstract:

    Photoacoustic Tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy.

  • quantitative Photoacoustic Tomography based on the radiative transfer equation
    Optics Letters, 2009
    Co-Authors: Huabei Jiang
    Abstract:

    We describe a method for quantitative Photoacoustic Tomography (PAT) based on the radiative transfer equation (RTE) coupled with the Helmholtz Photoacoustic wave equation. This RTE-based quantitative PAT allows for accurate recovery of absolute absorption coefficient images of heterogeneous media and provides significantly improved image reconstruction for the cases where the photon diffusion approximation may fail. The method and associated finite element reconstruction algorithm are validated using a series of tissuelike phantom experiments.

  • simultaneous recovery of tissue physiological and acoustic properties and the criteria for wavelength selection in multispectral Photoacoustic Tomography
    Optics Letters, 2009
    Co-Authors: Zhen Yuan, Huabei Jiang
    Abstract:

    We present an algorithm to directly reconstruct chromophore concentrations and acoustic velocity by multispectral Photoacoustic Tomography. We also derive the criterions to minimize the cross talk for simultaneous recovery of chromophore concentrations and acoustic velocity using multispectral Photoacoustic data. We found that the image quality and the separation between acoustic velocity and different chromophore concentrations strongly depend on the measurement wavelengths of incident laser source.

  • non invasive imaging of epileptic seizures in vivo using Photoacoustic Tomography
    Physics in Medicine and Biology, 2008
    Co-Authors: Qizhi Zhang, Zhen Yuan, Zhao Liu, Paul R Carney, Huanxin Chen, Steven N Roper, Huabei Jiang
    Abstract:

    Non-invasive laser-induced Photoacoustic Tomography (PAT) is an emerging imaging modality that has the potential to image the dynamic function of the brain due to its unique ability of imaging biological tissues with high optical contrast and ultrasound resolution. Here we report the first application of our finite-element-based PAT for imaging of epileptic seizures in an animal model. In vivo Photoacoustic images were obtained in rats with focal seizures induced by microinjection of bicuculline, a GABA(A) antagonist, into the neocortex. The seizure focus was accurately localized by PAT as confirmed with gold-standard electroencephalogram (EEG). Compared to the existing neuroimaging modalities, PAT not only has the unprecedented advantage of high spatial and temporal resolution in a single imaging modality, but also is portable and low in cost, making it possible to bring brain imaging to the bedside.

  • reconstruction of optical absorption coefficient maps of heterogeneous media by Photoacoustic Tomography coupled with diffusion equation based regularized newton method
    Optics Express, 2007
    Co-Authors: Zhen Yuan, Qiang Wang, Huabei Jiang
    Abstract:

    We describe a novel reconstruction method that allows for quantitative recovery of optical absorption coefficient maps of heterogeneous media using tomographic Photoacoustic measurements. Images of optical absorption coefficient are obtained from a diffusion equation based regularized Newton method where the absorbed energy density distribution from conventional Photoacoustic Tomography serves as the measured field data. We experimentally demonstrate this new method using tissue-mimicking phantom measurements and simulations. The reconstruction results show that the optical absorption coefficient images obtained are quantitative in terms of the shape, size, location and optical property values of the heterogeneities examined.

Zhen Yuan - One of the best experts on this subject based on the ideXlab platform.

Simon R Arridge - One of the best experts on this subject based on the ideXlab platform.

  • single pixel camera Photoacoustic Tomography
    Journal of Biomedical Optics, 2019
    Co-Authors: Nam Huynh, Edward Z. Zhang, Simon R Arridge, Paul C. Beard, Marta M Betcke, Felix Lucka, Benjamin T Cox
    Abstract:

    Since it was first demonstrated more than a decade ago, the single-pixel camera concept has been used in numerous applications in which it is necessary or advantageous to reduce the channel count, cost, or data volume. Here, three-dimensional (3-D), compressed-sensing Photoacoustic Tomography (PAT) is demonstrated experimentally using a single-pixel camera. A large area collimated laser beam is reflected from a planar Fabry–Perot ultrasound sensor onto a digital micromirror device, which patterns the light using a scrambled Hadamard basis before it is collected into a single photodetector. In this way, inner products of the Hadamard patterns and the distribution of thickness changes of the FP sensor—induced by the Photoacoustic waves—are recorded. The initial distribution of acoustic pressure giving rise to those Photoacoustic waves is recovered directly from the measured signals using an accelerated proximal gradient-type algorithm to solve a model-based minimization with total variation regularization. Using this approach, it is shown that 3-D PAT of imaging phantoms can be obtained with compression rates as low as 10%. Compressed sensing approaches to Photoacoustic imaging, such as this, have the potential to reduce the data acquisition time as well as the volume of data it is necessary to acquire, both of which are becoming increasingly important in the drive for faster imaging systems giving higher resolution images with larger fields of view.

  • acoustic wave field reconstruction from compressed measurements with application in Photoacoustic Tomography
    IEEE Transactions on Computational Imaging, 2017
    Co-Authors: Marta M Betcke, Edward Z. Zhang, Nam Huynh, Paul C. Beard, Simon R Arridge
    Abstract:

    We present a method for the recovery of compressively sensed acoustic fields using patterned, instead of point-by-point, detection. From a limited number of such compressed measurements, we propose to reconstruct the field on the sensor plane in each time step independently assuming its sparsity in a Curvelet frame. A modification of the Curvelet frame is proposed to account for the smoothing effects of data acquisition and motivated by a frequency domain model for Photoacoustic Tomography. An ADMM type algorithm, split augmented Lagrangian shrinkage algorithm, is used to recover the pointwise data in each individual time step from the patterned measurements. For Photoacoustic applications, the Photoacoustic image of the initial pressure is reconstructed using time reversal in $ {\mathbf k}$ -Wave Toolbox.

  • utilising the radiative transfer equation in quantitative Photoacoustic Tomography
    Proceedings of SPIE, 2017
    Co-Authors: Tanja Tarvainen, Aki Pulkkinen, Simon R Arridge
    Abstract:

    Quantitative Photoacoustic Tomography is an emerging imaging technique aimed at estimating optical parameters inside tissue from Photoacoustic images. This optical parameter estimation problem is an ill-posed inverse problem, and thus it is sensitive to measurement and modelling errors. Therefore, light propagation in quantitative Photoacoustic Tomography needs to be accurately modelled. A widely accepted model for light propagation in biological tissue is the radiative transfer equation. In this work, the radiative transfer equation is utilised in quantitative Photoacoustic Tomography. Estimating absorption and scattering distributions in quantitative Photoacoustic Tomography using various illuminations is investigated.

  • on the adjoint operator in Photoacoustic Tomography
    Inverse Problems, 2016
    Co-Authors: Simon R Arridge, Marta M Betcke, Ben Cox, Felix Lucka, B E Treeby
    Abstract:

    Photoacoustic Tomography (PAT) is an emerging biomedical imaging from coupled physics technique, in which the image contrast is due to optical absorption, but the information is carried to the surface of the tissue as ultrasound pulses. Many algorithms and formulae for PAT image reconstruction have been proposed for the case when a complete data set is available. In many practical imaging scenarios, however, it is not possible to obtain the full data, or the data may be sub-sampled for faster data acquisition. In such cases, image reconstruction algorithms that can incorporate prior knowledge to ameliorate the loss of data are required. Hence, recently there has been an increased interest in using variational image reconstruction. A crucial ingredient for the application of these techniques is the adjoint of the PAT forward operator, which is described in this article from physical, theoretical and numerical perspectives. First, a simple mathematical derivation of the adjoint of the PAT forward operator in the continuous framework is presented. Then, an efficient numerical implementation of the adjoint using a k-space time domain wave propagation model is described and illustrated in the context of variational PAT image reconstruction, on both 2D and 3D examples including inhomogeneous sound speed. The principal advantage of this analytical adjoint over an algebraic adjoint (obtained by taking the direct adjoint of the particular numerical forward scheme used) is that it can be implemented using currently available fast wave propagation solvers.

  • acoustic wave field reconstruction from compressed measurements with application in Photoacoustic Tomography
    arXiv: Numerical Analysis, 2016
    Co-Authors: Marta M Betcke, Edward Z. Zhang, Nam Huynh, Paul C. Beard, Simon R Arridge
    Abstract:

    We present a method for the recovery of compressively sensed acoustic fields using patterned, instead of point-by-point, detection. From a limited number of such compressed measurements, we propose to reconstruct the field on the sensor plane in each time step independently assuming its sparsity in a Curvelet frame. A modification of the Curvelet frame is proposed to account for the smoothing effects of data acquisition and motivated by a frequency domain model for Photoacoustic Tomography. An ADMM type algorithm, SALSA, is used to recover the pointwise data in each individual time step from the patterned measurements. For Photoacoustic applications, the Photoacoustic image of the initial pressure is reconstructed using time reversal in ${\bf k}$-Wave Toolbox.

Manojit Pramanik - One of the best experts on this subject based on the ideXlab platform.

  • recent advances toward preclinical and clinical translation of Photoacoustic Tomography a review
    Journal of Biomedical Optics, 2016
    Co-Authors: Paul Kumar Upputuri, Manojit Pramanik
    Abstract:

    Photoacoustic imaging is an emerging hybrid imaging modality that can provide multicontrast, multiscale imaging of biological features ranging from organelles to organs. The three major embodiments of Photoacoustic imaging are microscopy, endoscopy, and computed Tomography. Photoacoustic Tomography (PAT) or Photoacoustic computed Tomography allows deep-tissue imaging, and hence it is more suitable for whole body preclinical/clinical imaging applications. Due to fast-growing laser technology and ultrasound detector technology, PAT is evolving rapidly, leading to a quicker translation into clinical trials. We review the recent developments of PAT systems and their applications in preclinical and clinical practices.

  • performance characterization of low cost high speed portable pulsed laser diode Photoacoustic Tomography pld pat system
    Biomedical Optics Express, 2015
    Co-Authors: Paul Kumar Upputuri, Manojit Pramanik
    Abstract:

    Photoacoustic Tomography systems that uses Q-switched Nd:YAG/OPO pulsed lasers are expensive, bulky, and hence limits its use in clinical applications. The low pulse repetition rate of these lasers makes it unsuitable for real-time imaging when used with single-element ultrasound detector. In this work, we present a pulsed laser diode Photoacoustic Tomography (PLD-PAT) system that integrates a compact PLD inside a single-detector circular scanning geometry. We compared its performance against the traditional Nd:YAG/OPO based PAT system in terms of imaging depth, resolution, imaging time etc. The PLD provides near-infrared pulses at ~803 nm wavelength with pulse energy ~1.4 mJ/pulse at 7 kHz repetition rate. The PLD-PAT system is capable of providing 2D image in scan time as small as 3 sec with a signal-to-noise ratio ~30. High-speed and deep-tissue imaging is demonstrated on phantoms and biological samples. The PLD-PAT system is inexpensive, portable, allows high-speed PAT imaging, and its performance is as good as traditional expensive OPO based PAT system. Therefore, it holds promises for future translational biomedical imaging applications.

  • basis pursuit deconvolution for improving model based reconstructed images in Photoacoustic Tomography
    Biomedical Optics Express, 2014
    Co-Authors: Jaya Prakash, Manojit Pramanik, Aditi Subramani Raju, Calvin B Shaw, Phaneendra K Yalavarthy
    Abstract:

    The model-based image reconstruction approaches in Photoacoustic Tomography have a distinct advantage compared to traditional analytical methods for cases where limited data is available. These methods typically deploy Tikhonov based regularization scheme to reconstruct the initial pressure from the boundary acoustic data. The model-resolution for these cases represents the blur induced by the regularization scheme. A method that utilizes this blurring model and performs the basis pursuit deconvolution to improve the quantitative accuracy of the reconstructed Photoacoustic image is proposed and shown to be superior compared to other traditional methods via three numerical experiments. Moreover, this deconvolution including the building of an approximate blur matrix is achieved via the Lanczos bidagonalization (least-squares QR) making this approach attractive in real-time.

  • molecular Photoacoustic Tomography with colloidal nanobeacons
    Angewandte Chemie, 2009
    Co-Authors: Dipanjan Pan, Xinmai Yang, Manojit Pramanik, Angana Senpan, Kwang H Song, Michael J Scott, Huiying Zhang, Patrick J Gaffney, Samuel A Wickline, Lihong V Wang
    Abstract:

    Spotting clots: Vascularly constrained colloidal gold nanobeacons (GNBs; see picture) can be used as exogenous Photoacoustic contrast agents for the targeted detection of fibrin, a major biochemical feature of thrombus. Fibrin-targeted GNBs provide a more than tenfold signal enhancement in Photoacoustic Tomography in the near-IR wavelength window, indicating their potential for diagnostic imaging.

  • tangential resolution improvement in thermoacoustic and Photoacoustic Tomography using a negative acoustic lens
    Journal of Biomedical Optics, 2009
    Co-Authors: Manojit Pramanik, Geng Ku, Lihong V Wang
    Abstract:

    We developed a novel concept of using a negative acoustic lens to increase the acceptance angle of an unfocused large-area ultrasonic transducer (detector), leading to more than twofold improvement of the tangential resolution in both thermoacoustic and Photoacoustic Tomography. In both thermoacoustic and Photoacoustic Tomography, for a given transducer bandwidth, the aperture size of the detector affects the tangential resolution greatly when the object of interest is near the detector surface. We were able to overcome such tangential resolution deterioration by attaching an acoustic concave lens, made of acrylic in front of the flat detector surface. We then quantified the tangential resolution improvement using phantom images. We also showed that the use of the negative lens preserves the shape of an object after the image is reconstructed.