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Li S, Qin Y, Wang X, Yang X. Bubble growth in cylindrically-shaped optical absorbers during photo-mediated ultrasound therapy. Phys Med Biol 2018; 63:125017. [PMID: 29794345 DOI: 10.1088/1361-6560/aac7bc] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Photo-mediated ultrasound therapy (PUT) is a non-invasive, agent-free technique to shut down microvessels with high precision by promoting cavitation activity precisely in the targeted microvessels. PUT is based on the photoacoustic (PA) cavitation generated through concurrently applied nanosecond laser pulses and ultrasound bursts. In this study, a PA cavitation model is employed to understand the enhanced cavitation activity during PUT, with full consideration of the optical absorption of blood vessels. Bubble size evolution in cylindrically-shaped optical absorbers (vessels) due to rectified diffusion is simulated. Results show that the ultrasound pressure required for bubble growth decreases dramatically with the increased laser fluence. At a relatively low ultrasound driving pressure, bubble equilibrium radius increases rapidly due to concurrently applied nanosecond laser pulses and ultrasound bursts, resulting in a transition from inertial cavitation to stable cavitation. This inertial to stable transition is verified by the experimentally measured results on 0.76 mm silicone tubes filled with human whole blood with 0.5 MHz ultrasound at 0.243 MPa. This study demonstrated the potential to induce stable bubbles in blood vessels by PUT non-invasively.
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Affiliation(s)
- Shuying Li
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, United States of America. These two authors contribute equally to the work
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2
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Demirkiran A, Karakuzu A, Erkol H, Torun H, Unlu MB. Analysis of microcantilevers excited by pulsed-laser-induced photoacoustic waves. OPTICS EXPRESS 2018; 26:4906-4919. [PMID: 29475334 DOI: 10.1364/oe.26.004906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/04/2018] [Indexed: 06/08/2023]
Abstract
This study presents a simulation-based analysis on the excitation of microcantilever in air using pulsed-laser-induced photoacoustic waves. A model was designed and coded to investigate the effects of consecutive photoacoustic waves, arising from a spherical light absorber illuminated by short laser pulses. The consecutiveness of the waves were adjusted with respect to the pulse repetition frequency of the laser to examine their cumulative effects on the oscillation of microcantilever. Using this approach, oscillation characteristics of two rectangular cantilevers with different resonant frequencies (16.9 kHz and 505.7 kHz) were investigated in the presence of the random oscillations. The results show that the effective responses of the microcantilevers to the consecutive photoacoustic waves provide steady-state oscillations, when the pulse repetition frequency matches to the fundamental resonant frequency or its lower harmonics. Another major finding is that being driven by the same photoacoustic pressure value, the high frequency cantilever tend to oscillate at higher amplitudes. Some of the issues emerging from these findings may find application area in atomic force microscopy actuation and photoacoustic signal detection.
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Dana N, Sowers T, Karpiouk A, Vanderlaan D, Emelianov S. Optimization of dual-wavelength intravascular photoacoustic imaging of atherosclerotic plaques using Monte Carlo optical modeling. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-12. [PMID: 29076309 PMCID: PMC5658287 DOI: 10.1117/1.jbo.22.10.106012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/28/2017] [Indexed: 05/09/2023]
Abstract
Coronary heart disease (the presence of coronary atherosclerotic plaques) is a significant health problem in the industrialized world. A clinical method to accurately visualize and characterize atherosclerotic plaques is needed. Intravascular photoacoustic (IVPA) imaging is being developed to fill this role, but questions remain regarding optimal imaging wavelengths. We utilized a Monte Carlo optical model to simulate IVPA excitation in coronary tissues, identifying optimal wavelengths for plaque characterization. Near-infrared wavelengths (≤1800 nm) were simulated, and single- and dual-wavelength data were analyzed for accuracy of plaque characterization. Results indicate light penetration is best in the range of 1050 to 1370 nm, where 5% residual fluence can be achieved at clinically relevant depths of ≥2 mm in arteries. Across the arterial wall, fluence may vary by over 10-fold, confounding plaque characterization. For single-wavelength results, plaque segmentation accuracy peaked at 1210 and 1720 nm, though correlation was poor (<0.13). Dual-wavelength analysis proved promising, with 1210 nm as the most successful primary wavelength (≈1.0). Results suggest that, without flushing the luminal blood, a primary and secondary wavelength near 1210 and 1350 nm, respectively, may offer the best implementation of dual-wavelength IVPA imaging. These findings could guide the development of a cost-effective clinical system by highlighting optimal wavelengths and improving plaque characterization.
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Affiliation(s)
- Nicholas Dana
- University of Texas at Austin, Department of Biomedical Engineering, Austin, Texas, United States
| | - Timothy Sowers
- Georgia Institute of Technology, Parker H. Petit Institute for Bioengineering and Bioscience, Atlanta, Georgia, United States
- Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, Georgia, United States
| | - Andrei Karpiouk
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
| | - Donald Vanderlaan
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
| | - Stanislav Emelianov
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
- Emory University School of Medicine, Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
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Jo J, Yang X. Laser-enhanced high-intensity focused ultrasound heating in an in vivo small animal model. APPLIED PHYSICS LETTERS 2016; 109:213702. [PMID: 27965517 PMCID: PMC5123994 DOI: 10.1063/1.4968509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 11/09/2016] [Indexed: 05/17/2023]
Abstract
The enhanced heating effect during the combination of high-intensity focused ultrasound (HIFU) and low-optical-fluence laser illumination was investigated by using an in vivo murine animal model. The thighs of murine animals were synergistically irradiated by HIFU and pulsed nano-second laser light. The temperature increases in the target region were measured by a thermocouple under different HIFU pressures, which were 6.2, 7.9, and 9.8 MPa, in combination with 20 mJ/cm2 laser exposures at 532 nm wavelength. In comparison with conventional laser therapies, the laser fluence used here is at least one order of magnitude lower. The results showed that laser illumination could enhance temperature during HIFU applications. Additionally, cavitation activity was enhanced when laser and HIFU irradiation were concurrently used. Further, a theoretical simulation showed that the inertial cavitation threshold was indeed decreased when laser and HIFU irradiation were utilized concurrently.
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Affiliation(s)
- Janggun Jo
- KU Bioengineering Research Center and Department of Mechanical Engineering, University of Kansas , 1530 W. 15th Street, 5109 Learned Hall, Lawrence, Kansas 66045, USA
| | - Xinmai Yang
- KU Bioengineering Research Center and Department of Mechanical Engineering, University of Kansas , 1530 W. 15th Street, 5109 Learned Hall, Lawrence, Kansas 66045, USA
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Simulating photoacoustic waves produced by individual biological particles with spheroidal wave functions. Sci Rep 2015; 5:14801. [PMID: 26442830 PMCID: PMC4595827 DOI: 10.1038/srep14801] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 09/02/2015] [Indexed: 12/24/2022] Open
Abstract
Under the usual approximation of treating a biological particle as a spheroidal droplet, we consider the analysis of its size and shape with the high frequency photoacoustics and develop a numerical method which can simulate its characteristic photoacoustic waves. This numerical method is based on the calculation of spheroidal wave functions, and when comparing to the finite element model (FEM) calculation, can reveal more physical information and can provide results independently at each spatial points. As the demonstration, red blood cells (RBCs) and MCF7 cell nuclei are studied, and their photoacoustic responses including field distribution, spectral amplitude, and pulse forming are calculated. We expect that integrating this numerical method with the high frequency photoacoustic measurement will form a new modality being extra to the light scattering method, for fast assessing the morphology of a biological particle.
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Li Y, Fang H. Photoacoustic pulse wave forming along the rotation axis of an ellipsoid droplet: a geometric calculation study. APPLIED OPTICS 2013; 52:8258-8269. [PMID: 24513827 DOI: 10.1364/ao.52.008258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 10/20/2013] [Indexed: 06/03/2023]
Abstract
A geometric calculation method is developed to study the pulsed photoacoustic wave forming of an arbitrarily shaped droplet. It is found that for an ellipsoid droplet, either a prolate ellipsoid or an oblate ellipsoid, strict analytical formulas for describing the wave profile developed along the rotation axis can be derived. The results show intriguing differences compared to those of a sphere droplet in terms of the multiple geometric parameters being in effect, the pulse wave profile variant, and the existing of unlimited points of infinite tensile pressure.
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Wang B, Emelianov S. Thermal intravascular photoacoustic imaging. BIOMEDICAL OPTICS EXPRESS 2011; 2:3072-8. [PMID: 22076268 PMCID: PMC3207376 DOI: 10.1364/boe.2.003072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/30/2011] [Accepted: 10/03/2011] [Indexed: 05/20/2023]
Abstract
Intravascular photoacoustics (IVPA)-a minimally invasive imaging technique with contrast related to optical absorption properties of tissue, can be used to visualize atherosclerotic plaques. However, the amplitude of photoacoustic signals is also related to a temperature dependent, tissue specific parameter-the Grüneisen parameter. Therefore, photoacoustic signals measured at different temperatures may reveal information about tissue composition. In this study, thermal IVPA (tIVPA) imaging was introduced. The imaging studies were performed using an ex vivo atherosclerotic rabbit aorta. Temperature dependent photoacoustic responses from lipid in plaques and lipid in periadventitial tissue were different, thus allowing tIVPA images to delineate the location of lipid-rich plaques. The results indicate that tIVPA imaging has a potential to characterize tissue composition in atherosclerotic vessels.
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Faraggi E, Gerstman BS, Sun J. The emergence of chaos in a laser irradiated spherical absorber. CHAOS (WOODBURY, N.Y.) 2007; 17:013101. [PMID: 17411237 DOI: 10.1063/1.2407262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We show in this paper that the simple system of a spherical absorber immersed in water can exhibit complex and chaotic behavior upon absorption of laser energy. We report on computer experiments performed on this simple system. We present power spectra and calculate Lyapunov exponents that show that for increasing laser pulse durations and increasing laser energy the pressure response of the system changes from periodic to a regime displaying spatiotemporal chaos. This is important from a theoretical point of view because the complex behavior displayed in this simple system makes it an excellent choice for investigations into the nonlinear dynamics of fluids and the complicated transition to turbulence. This is also important for people using these systems for various applications in material science and biomedicine.
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Affiliation(s)
- Eshel Faraggi
- Physics Department, Florida International University, Miami, Florida 33199, USA.
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Faraggi E, Gerstman BS, Sun J. Biophysical effects of pulsed lasers in the retina and other tissues containing strongly absorbing particles: shockwave and explosive bubble generation. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:064029. [PMID: 16409094 DOI: 10.1117/1.2139970] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Damage by pulsed lasers to the retina or other tissues containing strongly absorbing particles may occur through biophysical mechanisms other than simple heating. Shockwaves and bubbles have been observed experimentally, and depending on pulse duration, may be the cause of retinal damage at threshold fluence levels. We perform detailed calculations on the shockwave and bubble generation expected from pulsed lasers. For a variety of different laser pulse durations and fluences, we tabulate the expected strength of the shockwave and size of the bubble that will be generated. We also explain how these results will change for absorbing particles with different physical properties such as absorption coefficient, bulk modulus, or thermal expansion coefficient. This enables the assessment of biological danger, and possible medical benefits, for lasers of a wide range of pulse durations and energies, incident on tissues with absorbing particles with a variety of thermomechanical characteristics.
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Affiliation(s)
- Eshel Faraggi
- Florida International University, Physics Department, Miami, Florida 33199, USA.
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Yang Y, Sun Z, Wang S, Dlott DD. Fast Spectroscopy of Laser-Initiated Nanoenergetic Materials. J Phys Chem B 2003. [DOI: 10.1021/jp0269322] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yanqiang Yang
- School of Chemical Sciences, Box 01-6 CLSL, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Zhaoyong Sun
- School of Chemical Sciences, Box 01-6 CLSL, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Shufeng Wang
- School of Chemical Sciences, Box 01-6 CLSL, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Dana D. Dlott
- School of Chemical Sciences, Box 01-6 CLSL, 600 South Mathews Avenue, Urbana, Illinois 61801
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Zhigilei LV, Leveugle E, Garrison BJ, Yingling YG, Zeifman MI. Computer simulations of laser ablation of molecular substrates. Chem Rev 2003; 103:321-48. [PMID: 12580634 DOI: 10.1021/cr010459r] [Citation(s) in RCA: 246] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leonid V Zhigilei
- Department of Materials Science and Engineering, 116 Engineer's Way, University of Virginia, Charlottesville, Virginia 22904, USA.
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Affiliation(s)
- Günther Paltauf
- Institute of Experimental Physics, Karl-Franzens-Universität Graz, Graz, Austria.
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