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Paul A, Mallidi S. U-Net enhanced real-time LED-based photoacoustic imaging. JOURNAL OF BIOPHOTONICS 2024; 17:e202300465. [PMID: 38622811 PMCID: PMC11164633 DOI: 10.1002/jbio.202300465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/18/2024] [Accepted: 03/17/2024] [Indexed: 04/17/2024]
Abstract
Photoacoustic (PA) imaging is hybrid imaging modality with good optical contrast and spatial resolution. Portable, cost-effective, smaller footprint light emitting diodes (LEDs) are rapidly becoming important PA optical sources. However, the key challenge faced by the LED-based systems is the low light fluence that is generally compensated by high frame averaging, consequently reducing acquisition frame-rate. In this study, we present a simple deep learning U-Net framework that enhances the signal-to-noise ratio (SNR) and contrast of PA image obtained by averaging low number of frames. The SNR increased by approximately four-fold for both in-class in vitro phantoms (4.39 ± 2.55) and out-of-class in vivo models (4.27 ± 0.87). We also demonstrate the noise invariancy of the network and discuss the downsides (blurry outcome and failure to reduce the salt & pepper noise). Overall, the developed U-Net framework can provide a real-time image enhancement platform for clinically translatable low-cost and low-energy light source-based PA imaging systems.
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Affiliation(s)
- Avijit Paul
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
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2
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Nyayapathi N, Zheng E, Zhou Q, Doyley M, Xia J. Dual-modal Photoacoustic and Ultrasound Imaging: from preclinical to clinical applications. FRONTIERS IN PHOTONICS 2024; 5:1359784. [PMID: 39185248 PMCID: PMC11343488 DOI: 10.3389/fphot.2024.1359784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Photoacoustic imaging is a novel biomedical imaging modality that has emerged over the recent decades. Due to the conversion of optical energy into the acoustic wave, photoacoustic imaging offers high-resolution imaging in depth beyond the optical diffusion limit. Photoacoustic imaging is frequently used in conjunction with ultrasound as a hybrid modality. The combination enables the acquisition of both optical and acoustic contrasts of tissue, providing functional, structural, molecular, and vascular information within the same field of view. In this review, we first described the principles of various photoacoustic and ultrasound imaging techniques and then classified the dual-modal imaging systems based on their preclinical and clinical imaging applications. The advantages of dual-modal imaging were thoroughly analyzed. Finally, the review ends with a critical discussion of existing developments and a look toward the future.
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Affiliation(s)
- Nikhila Nyayapathi
- Electrical and Computer Engineering, University of Rochester, Rochester, New York, 14627
| | - Emily Zheng
- Department of Biomedical Engineering, University at Buffalo, Buffalo, New York, 14226
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90007
| | - Marvin Doyley
- Electrical and Computer Engineering, University of Rochester, Rochester, New York, 14627
| | - Jun Xia
- Department of Biomedical Engineering, University at Buffalo, Buffalo, New York, 14226
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3
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Susmelj AK, Lafci B, Ozdemir F, Davoudi N, Deán-Ben XL, Perez-Cruz F, Razansky D. Signal domain adaptation network for limited-view optoacoustic tomography. Med Image Anal 2024; 91:103012. [PMID: 37922769 DOI: 10.1016/j.media.2023.103012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 09/19/2023] [Accepted: 10/18/2023] [Indexed: 11/07/2023]
Abstract
Optoacoustic (OA) imaging is based on optical excitation of biological tissues with nanosecond-duration laser pulses and detection of ultrasound (US) waves generated by thermoelastic expansion following light absorption. The image quality and fidelity of OA images critically depend on the extent of tomographic coverage provided by the US detector arrays. However, full tomographic coverage is not always possible due to experimental constraints. One major challenge concerns an efficient integration between OA and pulse-echo US measurements using the same transducer array. A common approach toward the hybridization consists in using standard linear transducer arrays, which readily results in arc-type artifacts and distorted shapes in OA images due to the limited angular coverage. Deep learning methods have been proposed to mitigate limited-view artifacts in OA reconstructions by mapping artifactual to artifact-free (ground truth) images. However, acquisition of ground truth data with full angular coverage is not always possible, particularly when using handheld probes in a clinical setting. Deep learning methods operating in the image domain are then commonly based on networks trained on simulated data. This approach is yet incapable of transferring the learned features between two domains, which results in poor performance on experimental data. Here, we propose a signal domain adaptation network (SDAN) consisting of i) a domain adaptation network to reduce the domain gap between simulated and experimental signals and ii) a sides prediction network to complement the missing signals in limited-view OA datasets acquired from a human forearm by means of a handheld linear transducer array. The proposed method showed improved performance in reducing limited-view artifacts without the need for ground truth signals from full tomographic acquisitions.
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Affiliation(s)
| | - Berkan Lafci
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland; Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Switzerland
| | - Firat Ozdemir
- Swiss Data Science Center, ETH Zürich and EPFL, Switzerland
| | - Neda Davoudi
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland; Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Switzerland
| | - Xosé Luís Deán-Ben
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland; Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Switzerland
| | - Fernando Perez-Cruz
- Swiss Data Science Center, ETH Zürich and EPFL, Switzerland; Institute for Machine Learning, Department of Computer Science, ETH Zurich, Switzerland
| | - Daniel Razansky
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland; Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Switzerland.
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Christie LB, Zheng W, Johnson W, Marecki EK, Heidrich J, Xia J, Oh KW. Review of imaging test phantoms. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:080903. [PMID: 37614568 PMCID: PMC10442662 DOI: 10.1117/1.jbo.28.8.080903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/25/2023]
Abstract
Significance Photoacoustic tomography has emerged as a prominent medical imaging technique that leverages its hybrid nature to provide deep penetration, high resolution, and exceptional optical contrast with notable applications in early cancer detection, functional brain imaging, drug delivery monitoring, and guiding interventional procedures. Test phantoms are pivotal in accelerating technology development and commercialization, specifically in photoacoustic (PA) imaging, and can be optimized to achieve significant advancements in PA imaging capabilities. Aim The analysis of material properties, structural characteristics, and manufacturing methodologies of test phantoms from existing imaging technologies provides valuable insights into their applicability to PA imaging. This investigation enables a deeper understanding of how phantoms can be effectively employed in the context of PA imaging. Approach Three primary categories of test phantoms (simple, intermediate, and advanced) have been developed to differentiate complexity and manufacturing requirements. In addition, four sub-categories (tube/channel, block, test target, and naturally occurring phantoms) have been identified to encompass the structural variations within these categories, resulting in a comprehensive classification system for test phantoms. Results Based on a thorough examination of literature and studies on phantoms in various imaging modalities, proposals have been put forth for the development of multiple PA-capable phantoms, encompassing considerations related to the material composition, structural design, and specific applications within each sub-category. Conclusions The advancement of novel and sophisticated test phantoms within each sub-category is poised to foster substantial progress in both the commercialization and development of PA imaging. Moreover, the continued refinement of test phantoms will enable the exploration of new applications and use cases for PA imaging.
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Affiliation(s)
- Liam B. Christie
- State University of New York at Buffalo, Sensors and MicroActuators Learning Lab, Electrical Engineering, Buffalo, New York, United States
| | - Wenhan Zheng
- State University of New York at Buffalo, Optical and Ultrasonic Imaging Laboratory, Biomedical Engineering, Buffalo, New York, United States
| | - William Johnson
- State University of New York at Buffalo, Sensors and MicroActuators Learning Lab, Electrical Engineering, Buffalo, New York, United States
| | - Eric K. Marecki
- State University of New York at Buffalo, Sensors and MicroActuators Learning Lab, Electrical Engineering, Buffalo, New York, United States
| | - James Heidrich
- State University of New York at Buffalo, Sensors and MicroActuators Learning Lab, Electrical Engineering, Buffalo, New York, United States
| | - Jun Xia
- State University of New York at Buffalo, Optical and Ultrasonic Imaging Laboratory, Biomedical Engineering, Buffalo, New York, United States
| | - Kwang W. Oh
- State University of New York at Buffalo, Sensors and MicroActuators Learning Lab, Electrical Engineering, Buffalo, New York, United States
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Liu X, Kalva SK, Lafci B, Nozdriukhin D, Deán-Ben XL, Razansky D. Full-view LED-based optoacoustic tomography. PHOTOACOUSTICS 2023; 31:100521. [PMID: 37342502 PMCID: PMC10277581 DOI: 10.1016/j.pacs.2023.100521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 06/23/2023]
Abstract
Optoacoustic tomography is commonly performed with bulky and expensive short-pulsed solid-state lasers providing high per-pulse energies in the millijoule range. Light emitting diodes (LEDs) represent a cost-effective and portable alternative for optoacoustic signal excitation that can additionally provide excellent pulse-to-pulse stability. Herein, we introduce a full-view LED-based optoacoustic tomography (FLOAT) system for deep tissue in vivo imaging. It is based on a custom-made electronic unit driving a stacked array of LEDs, which attains 100 ns pulse width and highly stable (0.62 % standard deviation) total per-pulse energy of 0.48 mJ. The illumination source is integrated into a circular array of cylindrically-focused ultrasound detection elements to result in a full-view tomographic configuration, which plays a critical role in circumventing limited-view effects, enhancing the effective field-of-view and image quality for cross-sectional (2D) imaging. We characterized the FLOAT performance in terms of pulse width, power stability, excitation light distribution, signal-to-noise and penetration depth. FLOAT of the human finger revealed a comparable imaging performance to that achieved with the standard pulsed Nd:YAG laser. It is anticipated that this compact, affordable and versatile illumination technology will facilitate optoacoustic imaging developments in resource-limited settings for biological and clinical applications.
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Affiliation(s)
- Xiang Liu
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
| | - Sandeep Kumar Kalva
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
| | - Berkan Lafci
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
| | - Daniil Nozdriukhin
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
| | - Xosé Luís Deán-Ben
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich CH-8093, Switzerland
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6
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Jo J, Mills D, Dentinger A, Chamberland D, Abdulaziz NM, Wang X, Schiopu E, Gandikota G. Photoacoustic Imaging of COVID-19 Vaccine Site Inflammation of Autoimmune Disease Patients. SENSORS (BASEL, SWITZERLAND) 2023; 23:2789. [PMID: 36904999 PMCID: PMC10006996 DOI: 10.3390/s23052789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/25/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Based on the observations made in rheumatology clinics, autoimmune disease (AD) patients on immunosuppressive (IS) medications have variable vaccine site inflammation responses, whose study may help predict the long-term efficacy of the vaccine in this at-risk population. However, the quantitative assessment of the inflammation of the vaccine site is technically challenging. In this study analyzing AD patients on IS medications and normal control subjects, we imaged the inflammation of the vaccine site 24 h after mRNA COVID-19 vaccinations were administered using both the emerging photoacoustic imaging (PAI) method and the established Doppler ultrasound (US) method. A total of 15 subjects were involved, including 6 AD patients on IS and 9 normal control subjects, and the results from the two groups were compared. Compared to the results obtained from the control subjects, the AD patients on IS medications showed statistically significant reductions in vaccine site inflammation, indicating that immunosuppressed AD patients also experience local inflammation after mRNA vaccination but not in as clinically apparent of a manner when compared to non-immunosuppressed non-AD individuals. Both PAI and Doppler US were able to detect mRNA COVID-19 vaccine-induced local inflammation. PAI, based on the optical absorption contrast, shows better sensitivity in assessing and quantifying the spatially distributed inflammation in soft tissues at the vaccine site.
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Affiliation(s)
- Janggun Jo
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Mills
- General Electric Research, Niskayuna, NY 12309, USA
| | | | - David Chamberland
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nada M. Abdulaziz
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xueding Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Elena Schiopu
- Division of Rheumatology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Girish Gandikota
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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7
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Lafci B, Robin J, Dean-Ben XL, Razansky D. Expediting Image Acquisition in Reflection Ultrasound Computed Tomography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2837-2848. [PMID: 35507610 DOI: 10.1109/tuffc.2022.3172713] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Reflection ultrasound computed tomography (RUCT) attains optimal image quality from objects that can be fully accessed from multiple directions, such as the human breast or small animals. Owing to the full-view tomography approach based on the compounding of images taken from multiple angles, RUCT effectively mitigates several deficiencies afflicting conventional pulse-echo ultrasound (US) systems, such as speckle patterns and interuser variability. On the other hand, the small interelement pitch required to fulfill the spatial sampling criterion in the circular transducer configuration used in RUCT typically implies the use of an excessive number of independent array elements. This increases the system's complexity and costs, and limits the achievable imaging speed. Here, we explore acquisition schemes that enable RUCT imaging with the reduced number of transmit/receive elements. We investigated the influence of the element size in transmission and reception in a ring array geometry. The performance of a sparse acquisition approach based on partial acquisition from a subset of the elements has been further assessed. A larger element size is shown to preserve contrast and resolution at the center of the field of view (FOV), while a reduced number of elements is shown to cause uniform loss of contrast and resolution across the entire FOV. The tradeoffs of achievable FOV, contrast-to-noise ratio, and temporal and spatial resolutions are assessed in phantoms and in vivo mouse experiments. The experimental analysis is expected to aid the development of optimized hardware and image acquisition strategies for RUCT and, thus, result in more affordable imaging systems facilitating wider adoption.
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Zhang Y, Wang Y, Lai P, Wang L. Video-Rate Dual-Modal Wide-Beam Harmonic Ultrasound and Photoacoustic Computed Tomography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:727-736. [PMID: 34694993 DOI: 10.1109/tmi.2021.3122240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Dual-modal ultrasound (US) and photoacoustic (PA) imaging has tremendous advantages in biomedical applications, such as pharmacokinetics, cancer screening, and imaging-guided therapy. Compared with ring-shaped arrays, a linear piezoelectric transducer array applies to more anatomical sites and has been widely used in US/PA imaging. However, the linear array may limit the imaging quality due to narrow bandwidth, partial detection view, or sparse spatial sampling. To meet clinic demand of high-quality US/PA imaging with the linear transducer, we develop dual-modal wide-beam harmonic ultrasound (WBHUS) and photoacoustic computed tomography at video rate. The harmonic US imaging employs pulse phase inversion to reduce clutters and improve spatial resolution. Wide-beam US transmission can shorten the scanning times by 267% and enables a 20-Hz imaging rate, which can minimize motion artifacts in in vivo imaging. The harmonic US imaging does not only provide accurate anatomical references for locating PA features but also reduces artifacts in PA images. The improved image quality allows us to acquire high-resolution anatomical structures in deep tissue without labeling. The fast-imaging speed enables visualizing interventional procedures and monitoring the pulsations of the thoracic aorta and radial artery in real-time. The video-rate dual-modal harmonic US and single-shot PA computed tomography use a clinical-grade linear-array transducer and thus can be readily implemented in clinical US imaging.
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Cheng Z, Wu L, Qiu T, Duan Y, Qin H, Hu J, Yang S. An Excitation-Reception Collinear Probe for Ultrasonic, Photoacoustic, and Thermoacoustic Tri-Modal Volumetric Imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:3498-3506. [PMID: 34125673 DOI: 10.1109/tmi.2021.3089243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Imaging systems that integrate multiple modalities can reveal complementary anatomic and functional information as they exploit different contrast mechanisms, which have shown great application potential and advantages in preclinical studies. A portable and easy-to-use imaging probe will be more conducive to transfer to clinical practice. Here, we present a tri-modal ultrasonic (US), photoacoustic (PA), and thermoacoustic (TA) imaging system with an excitation-reception collinear probe. The acoustic field, light field, and electric field of the probe were designed to be coaxial, realizing homogeneous illumination and high-sensitivity detection at the same detection position. US images can provide detailed information about structures, PA images can delineate the morphology of blood vessels in tissues, and TA images can reveal dielectric properties of the tissues. Moreover, phantoms and in vivo human finger experiments were performed by the tri-modal imaging system to demonstrate its performance. The results show that the tri-modal imaging system with the proposed probe has the ability to detect small breast tumors with a radius of only 2.5 mm and visualize the anatomical structure of the finger in three dimensions. Our work confirms that the tri-modal imaging system equipped with a collinear probe can be applied to a variety of different scenarios, which lays a solid foundation for the application of the tri-modality system in clinical trials.
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10
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Davoudi N, Lafci B, Özbek A, Deán-Ben XL, Razansky D. Deep learning of image- and time-domain data enhances the visibility of structures in optoacoustic tomography. OPTICS LETTERS 2021; 46:3029-3032. [PMID: 34197371 DOI: 10.1364/ol.424571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/15/2021] [Indexed: 06/13/2023]
Abstract
Images rendered with common optoacoustic system implementations are often afflicted with distortions and poor visibility of structures, hindering reliable image interpretation and quantification of bio-chrome distribution. Among the practical limitations contributing to artifactual reconstructions are insufficient tomographic detection coverage and suboptimal illumination geometry, as well as inability to accurately account for acoustic reflections and speed of sound heterogeneities in the imaged tissues. Here we developed a convolutional neural network (CNN) approach for enhancement of optoacoustic image quality which combines training on both time-resolved signals and tomographic reconstructions. Reference human finger data for training the CNN were recorded using a full-ring array system that provides optimal tomographic coverage around the imaged object. The reconstructions were further refined with a dedicated algorithm that minimizes acoustic reflection artifacts induced by acoustically mismatch structures, such as bones. The combined methodology is shown to outperform other learning-based methods solely operating on image-domain data.
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Photoacoustic Imaging of Human Vasculature Using LED versus Laser Illumination: A Comparison Study on Tissue Phantoms and In Vivo Humans. SENSORS 2021; 21:s21020424. [PMID: 33435375 PMCID: PMC7827532 DOI: 10.3390/s21020424] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/15/2022]
Abstract
Vascular diseases are becoming an epidemic with an increasing aging population and increases in obesity and type II diabetes. Point-of-care (POC) diagnosis and monitoring of vascular diseases is an unmet medical need. Photoacoustic imaging (PAI) provides label-free multiparametric information of deep vasculature based on strong absorption of light photons by hemoglobin molecules. However, conventional PAI systems use bulky nanosecond lasers which hinders POC applications. Recently, light-emitting diodes (LEDs) have emerged as cost-effective and portable optical sources for the PAI of living subjects. However, state-of-art LED arrays carry significantly lower optical energy (<0.5 mJ/pulse) and high pulse repetition frequencies (PRFs) (4 KHz) compared to the high-power laser sources (100 mJ/pulse) with low PRFs of 10 Hz. Given these tradeoffs between portability, cost, optical energy and frame rate, this work systematically studies the deep tissue PAI performance of LED and laser illuminations to help select a suitable source for a given biomedical application. To draw a fair comparison, we developed a fiberoptic array that delivers laser illumination similar to the LED array and uses the same ultrasound transducer and data acquisition platform for PAI with these two illuminations. Several controlled studies on tissue phantoms demonstrated that portable LED arrays with high frame averaging show higher signal-to-noise ratios (SNRs) of up to 30 mm depth, and the high-energy laser source was found to be more effective for imaging depths greater than 30 mm at similar frame rates. Label-free in vivo imaging of human hand vasculature studies further confirmed that the vascular contrast from LED-PAI is similar to laser-PAI for up to 2 cm depths. Therefore, LED-PAI systems have strong potential to be a mobile health care technology for diagnosing vascular diseases such as peripheral arterial disease and stroke in POC and resource poor settings.
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12
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Oxygen Saturation Imaging Using LED-Based Photoacoustic System. SENSORS 2021; 21:s21010283. [PMID: 33406653 PMCID: PMC7795655 DOI: 10.3390/s21010283] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/31/2022]
Abstract
Oxygen saturation imaging has potential in several preclinical and clinical applications. Dual-wavelength LED array-based photoacoustic oxygen saturation imaging can be an affordable solution in this case. For the translation of this technology, there is a need to improve its accuracy and validate it against ground truth methods. We propose a fluence compensated oxygen saturation imaging method, utilizing structural information from the ultrasound image, and prior knowledge of the optical properties of the tissue with a Monte-Carlo based light propagation model for the dual-wavelength LED array configuration. We then validate the proposed method with oximeter measurements in tissue-mimicking phantoms. Further, we demonstrate in vivo imaging on small animal and a human subject. We conclude that the proposed oxygen saturation imaging can be used to image tissue at a depth of 6–8 mm in both preclinical and clinical applications.
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13
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Mercuri M, Fernandez Rivas D. Challenges and opportunities for small volumes delivery into the skin. BIOMICROFLUIDICS 2021; 15:011301. [PMID: 33532017 PMCID: PMC7826167 DOI: 10.1063/5.0030163] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 01/09/2021] [Indexed: 05/04/2023]
Abstract
Each individual's skin has its own features, such as strength, elasticity, or permeability to drugs, which limits the effectiveness of one-size-fits-all approaches typically found in medical treatments. Therefore, understanding the transport mechanisms of substances across the skin is instrumental for the development of novel minimal invasive transdermal therapies. However, the large difference between transport timescales and length scales of disparate molecules needed for medical therapies makes it difficult to address fundamental questions. Thus, this lack of fundamental knowledge has limited the efficacy of bioengineering equipment and medical treatments. In this article, we provide an overview of the most important microfluidics-related transport phenomena through the skin and versatile tools to study them. Moreover, we provide a summary of challenges and opportunities faced by advanced transdermal delivery methods, such as needle-free jet injectors, microneedles, and tattooing, which could pave the way to the implementation of better therapies and new methods.
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Affiliation(s)
- Magalí Mercuri
- Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Av. Gral. Paz 1499, 1650 San Martín, Buenos Aires, Argentina
| | - David Fernandez Rivas
- Mesoscale Chemical Systems Group, MESA+ Institute, TechMed Centre and Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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14
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Das D, Sharma A, Rajendran P, Pramanik M. Another decade of photoacoustic imaging. Phys Med Biol 2020; 66. [PMID: 33361580 DOI: 10.1088/1361-6560/abd669] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/23/2020] [Indexed: 01/09/2023]
Abstract
Photoacoustic imaging - a hybrid biomedical imaging modality finding its way to clinical practices. Although the photoacoustic phenomenon was known more than a century back, only in the last two decades it has been widely researched and used for biomedical imaging applications. In this review we focus on the development and progress of the technology in the last decade (2010-2020). From becoming more and more user friendly, cheaper in cost, portable in size, photoacoustic imaging promises a wide range of applications, if translated to clinic. The growth of photoacoustic community is steady, and with several new directions researchers are exploring, it is inevitable that photoacoustic imaging will one day establish itself as a regular imaging system in the clinical practices.
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Affiliation(s)
- Dhiman Das
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Arunima Sharma
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Praveenbalaji Rajendran
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Manojit Pramanik
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, N1.3-B2-11, Singapore, 637457, SINGAPORE
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15
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Zhang Y, Wang L. Video-Rate Ring-Array Ultrasound and Photoacoustic Tomography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:4369-4375. [PMID: 32813650 DOI: 10.1109/tmi.2020.3017815] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ultrasonography and photoacoustic tomography provide complementary contrasts in preclinical studies, disease diagnoses, and imaging-guided interventional procedures. Here, we present a video-rate (20 Hz) dual-modality ultrasound and photoacoustic tomographic platform that has a high resolution, rich contrasts, deep penetration, and wide field of view. A three-quarter ring-array ultrasonic transducer is used for both ultrasound and photoacoustic imaging. Plane-wave transmission/receiving approach is used for ultrasound imaging, which improves the imaging speed by nearly two folds and reduces the RF data size compared with the sequential single-channel scanning approach. GPU-based image reconstruction is developed to advance computational speed. We demonstrate fast dual-modality imaging in phantom, mouse, and human finger joint experiments. The results show respiration motion, heart beating, and detailed features in the mouse internal organs. To our knowledge, this is the first report on fast plane-wave ultrasound imaging and single-shot photoacoustic computed tomography in a ring-array system.
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Jo J, Xu G, Schiopu E, Chamberland D, Gandikota G, Wang X. Imaging of enthesitis by an LED-based photoacoustic system. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200274RR. [PMID: 33331148 PMCID: PMC7744251 DOI: 10.1117/1.jbo.25.12.126005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/01/2020] [Indexed: 05/03/2023]
Abstract
SIGNIFICANCE One key pathological characteristic of seronegative spondyloarthropathy (SpA) is inflammation at the insertion of tendons and ligaments into the bone (enthesitis). AIM We explore the potential of the emerging photoacoustic (PA) imaging in diagnosis of SpA and review its feasibility in detecting SpA-associated Achilles tendon enthesitis. APPROACH A light-emitting diode (LED)-based PA and ultrasound combined system was employed. The PA images, both along the long and the short axes of each Achilles tendon insertion region, were acquired at 850-nm wavelength, which is sensitive in depicting increased blood volume (i.e., hyperemia). To assess the hyperemia indicating enthesis inflammation, two parameters were quantified in the imaged tendons, including the average intensity and the density of the color pixels in the pseudo-color PA images. Ten SpA patients, all of which met Assessment of SpA International Society (ASAS) criteria for SpA and were found to have Achilles enthesitis by clinical exam according to a board-certified rheumatologist, were included in the study. RESULTS The PA and Doppler ultrasound imaging of Achilles enthesitis resulting from these 10 SpA patients were compared to those from 10 healthy volunteers, leading to statistically significant differences (p < 0.05) in the applied t-tests. CONCLUSIONS This preliminary clinical study suggests that the LED-based PA imaging holds a promise for sensitive and objective assessment of SpA enthesitis in an outpatient setting of the rheumatology clinic.
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Affiliation(s)
- Janggun Jo
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
| | - Guan Xu
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, United States
| | - Elena Schiopu
- University of Michigan Medical School, Division of Rheumatology, Department of Internal Medicine, Ann Arbor, Michigan, United States
- Address all correspondence to Elena Schiopu, ; Girish Gandikota, ; Xueding Wang,
| | - David Chamberland
- University of Michigan Medical School, Division of Rheumatology, Department of Internal Medicine, Ann Arbor, Michigan, United States
| | - Girish Gandikota
- University of Michigan Medical School, Department of Radiology, Ann Arbor, Michigan, United States
- Address all correspondence to Elena Schiopu, ; Girish Gandikota, ; Xueding Wang,
| | - Xueding Wang
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
- University of Michigan Medical School, Department of Radiology, Ann Arbor, Michigan, United States
- Address all correspondence to Elena Schiopu, ; Girish Gandikota, ; Xueding Wang,
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Kelly C, Refaee A, Salcudean SE. Integrating photoacoustic tomography into a multimodal automated breast ultrasound scanner. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200233RR. [PMID: 33215477 PMCID: PMC7675066 DOI: 10.1117/1.jbo.25.11.116010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 10/26/2020] [Indexed: 05/12/2023]
Abstract
SIGNIFICANCE Photoacoustic tomography (PAT) is a promising emergent modality for the screening and staging of breast cancer. To minimize barriers to clinical translation, it is common to develop PAT systems based upon existing ultrasound hardware, which can entail significant design challenges in terms of light delivery. This often results in inherently non-uniform fluence within the tissue and should be accounted for during image reconstruction. AIM We aim to integrate PAT into an automated breast ultrasound scanner with minimal change to the existing system. APPROACH We designed and implemented an illuminator that directs spatially non-uniform light to the tissue near the acquisition plane of the imaging array. We developed a graphics processing unit-accelerated reconstruction method, which accounts for this illumination geometry by modeling the structure of the light in the sample. We quantified the performance of this system using a custom, modular photoacoustic phantom and graphite rods embedded in chicken breast tissue. RESULTS Our illuminator provides a fluence of 2.5 mJ cm - 2 at the tissue surface, which was sufficient to attain a signal-to-noise ratio (SNR) of 8 dB at 2 cm in chicken breast tissue and image 0.25-mm features at depths of up to 3 cm in a medium with moderate optical scattering. Our reconstruction scheme is 200 × faster than a CPU implementation; it provides a 25% increase in SNR at 2 cm in chicken breast tissue and lowers image error by an average of 31% at imaging depths >1.5 cm compared with a method that does not account for the inhomogeneity of the illumination or the transducer directivity. CONCLUSIONS A fan-shaped illumination geometry is feasible for PAT; however, it is important to account for non-uniform fluence in illumination scenarios such as this. Future work will focus on increasing fluence and further optimizing the ultrasound hardware to improve SNR and overall image quality.
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Affiliation(s)
- Corey Kelly
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, British Columbia, Canada
| | - Amir Refaee
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, British Columbia, Canada
| | - Septimiu E. Salcudean
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, British Columbia, Canada
- Address all correspondence to Septimiu E. Salcudean,
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Kuniyil Ajith Singh M, Xia W. Portable and Affordable Light Source-Based Photoacoustic Tomography. SENSORS (BASEL, SWITZERLAND) 2020; 20:E6173. [PMID: 33138296 PMCID: PMC7663770 DOI: 10.3390/s20216173] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022]
Abstract
Photoacoustic imaging is a hybrid imaging modality that offers the advantages of optical (spectroscopic contrast) and ultrasound imaging (scalable spatial resolution and imaging depth). This promising modality has shown excellent potential in a wide range of preclinical and clinical imaging and sensing applications. Even though photoacoustic imaging technology has matured in research settings, its clinical translation is not happening at the expected pace. One of the main reasons for this is the requirement of bulky and expensive pulsed lasers for excitation. To accelerate the clinical translation of photoacoustic imaging and explore its potential in resource-limited settings, it is of paramount importance to develop portable and affordable light sources that can be used as the excitation light source. In this review, we focus on the following aspects: (1) the basic theory of photoacoustic imaging; (2) inexpensive light sources and different implementations; and (3) important preclinical and clinical applications, demonstrated using affordable light source-based photoacoustics. The main focus will be on laser diodes and light-emitting diodes as they have demonstrated promise in photoacoustic tomography-the key technological developments in these areas will be thoroughly reviewed. We believe that this review will be a useful opus for both the beginners and experts in the field of biomedical photoacoustic imaging.
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Affiliation(s)
- Mithun Kuniyil Ajith Singh
- Research and Business Development Division, CYBERDYNE INC., Stationsplein 45, A4.004, 3013 AK Rotterdam, The Netherlands;
| | - Wenfeng Xia
- School of Biomedical Engineering& Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, UK
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Tsang VT, Li X, Wong TT. A Review of Endogenous and Exogenous Contrast Agents Used in Photoacoustic Tomography with Different Sensing Configurations. SENSORS 2020; 20:s20195595. [PMID: 33003566 PMCID: PMC7582683 DOI: 10.3390/s20195595] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/17/2022]
Abstract
Optical-based sensing approaches have long been an indispensable way to detect molecules in biological tissues for various biomedical research and applications. The advancement in optical microscopy is one of the main drivers for discoveries and innovations in both life science and biomedical imaging. However, the shallow imaging depth due to the use of ballistic photons fundamentally limits optical imaging approaches’ translational potential to a clinical setting. Photoacoustic (PA) tomography (PAT) is a rapidly growing hybrid imaging modality that is capable of acoustically detecting optical contrast. PAT uniquely enjoys high-resolution deep-tissue imaging owing to the utilization of diffused photons. The exploration of endogenous contrast agents and the development of exogenous contrast agents further improve the molecular specificity for PAT. PAT’s versatile design and non-invasive nature have proven its great potential as a biomedical imaging tool for a multitude of biomedical applications. In this review, representative endogenous and exogenous PA contrast agents will be introduced alongside common PAT system configurations, including the latest advances of all-optical acoustic sensing techniques.
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Xavierselvan M, Singh MKA, Mallidi S. In Vivo Tumor Vascular Imaging with Light Emitting Diode-Based Photoacoustic Imaging System. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4503. [PMID: 32806575 PMCID: PMC7472236 DOI: 10.3390/s20164503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/13/2022]
Abstract
Photoacoustic (PA) imaging has shown tremendous promise for imaging tumor vasculature and its function at deeper penetration depths without the use of exogenous contrast agents. Traditional PA imaging systems employ expensive and bulky class IV lasers with low pulse repetition rate, due to which its availability for preclinical cancer research is hampered. In this study, we evaluated the capability of a Light-Emitting Diode (LED)-based PA and ultrasound (US) imaging system for monitoring heterogeneous microvasculature in tumors (up to 10 mm in depth) and quantitatively compared the PA images with gold standard histology images. We used a combination of a 7 MHz linear array US transducer and 850 nm excitation wavelength LED arrays to image blood vessels in a subcutaneous tumor model. After imaging, the tumors were sectioned and stained for endothelial cells to correlate with PA images across similar cross-sections. Analysis of 30 regions of interest in tumors from different mice showed a statistically significant R-value of 0.84 where the areas with high blood vessel density had high PA response while low blood vessel density regions had low PA response. Our results confirm that LED-based PA and US imaging can provide 2D and 3D images of tumor vasculature and the potential it has as a valuable tool for preclinical cancer research.
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Affiliation(s)
- Marvin Xavierselvan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA;
| | - Mithun Kuniyil Ajith Singh
- Research & Business Development Division, Cyberdyne INC, Cambridge Innovation Center, 3013 Rotterdam, The Netherlands;
| | - Srivalleesha Mallidi
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA;
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Kuriakose M, Nguyen CD, Kuniyil Ajith Singh M, Mallidi S. Optimizing Irradiation Geometry in LED-Based Photoacoustic Imaging with 3D Printed Flexible and Modular Light Delivery System. SENSORS 2020; 20:s20133789. [PMID: 32640683 PMCID: PMC7374354 DOI: 10.3390/s20133789] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 01/04/2023]
Abstract
Photoacoustic (PA) imaging–a technique combining the ability of optical imaging to probe functional properties of the tissue and deep structural imaging ability of ultrasound–has gained significant popularity in the past two decades for its utility in several biomedical applications. More recently, light-emitting diodes (LED) are being explored as an alternative to bulky and expensive laser systems used in PA imaging for their portability and low-cost. Due to the large beam divergence of LEDs compared to traditional laser beams, it is imperative to quantify the angular dependence of LED-based illumination and optimize its performance for imaging superficial or deep-seated lesions. A custom-built modular 3-D printed hinge system and tissue-mimicking phantoms with various absorption and scattering properties were used in this study to quantify the angular dependence of LED-based illumination. We also experimentally calculated the source divergence of the pulsed-LED arrays to be 58° ± 8°. Our results from point sources (pencil lead phantom) in non-scattering medium obey the cotangential relationship between the angle of irradiation and maximum PA intensity obtained at various imaging depths, as expected. Strong dependence on the angle of illumination at superficial depths (−5°/mm at 10 mm) was observed that becomes weaker at intermediate depths (−2.5°/mm at 20 mm) and negligible at deeper locations (−1.1°/mm at 30 mm). The results from the tissue-mimicking phantom in scattering media indicate that angles between 30–75° could be used for imaging lesions at various depths (12 mm–28 mm) where lower LED illumination angles (closer to being parallel to the imaging plane) are preferable for deep tissue imaging and superficial lesion imaging is possible with higher LED illumination angles (closer to being perpendicular to the imaging plane). Our results can serve as a priori knowledge for the future LED-based PA system designs employed for both preclinical and clinical applications.
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Affiliation(s)
- Maju Kuriakose
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
| | - Christopher D. Nguyen
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
| | | | - Srivalleesha Mallidi
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
- Correspondence:
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Tomographic Ultrasound and LED-Based Photoacoustic System for Preclinical Imaging. SENSORS 2020; 20:s20102793. [PMID: 32422995 PMCID: PMC7294432 DOI: 10.3390/s20102793] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 01/19/2023]
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.
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Towards Clinical Translation of LED-Based Photoacoustic Imaging: A Review. SENSORS 2020; 20:s20092484. [PMID: 32349414 PMCID: PMC7249023 DOI: 10.3390/s20092484] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 12/14/2022]
Abstract
Photoacoustic imaging, with the capability to provide simultaneous structural, functional, and molecular information, is one of the fastest growing biomedical imaging modalities of recent times. As a hybrid modality, it not only provides greater penetration depth than the purely optical imaging techniques, but also provides optical contrast of molecular components in the living tissue. Conventionally, photoacoustic imaging systems utilize bulky and expensive class IV lasers, which is one of the key factors hindering the clinical translation of this promising modality. Use of LEDs which are portable and affordable offers a unique opportunity to accelerate the clinical translation of photoacoustics. In this paper, we first review the development history of LED as an illumination source in biomedical photoacoustic imaging. Key developments in this area, from point-source measurements to development of high-power LED arrays, are briefly discussed. Finally, we thoroughly review multiple phantom, ex-vivo, animal in-vivo, human in-vivo, and clinical pilot studies and demonstrate the unprecedented preclinical and clinical potential of LED-based photoacoustic imaging.
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