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Abstract
The detection of ultrasound in photoacoustic tomography (PAT) usually relies on ultrasonic transducers in contact with the biological tissue through a coupling medium. This is a major drawback for important potential applications such as surgery. Here we report the use of a remote optical method, derived from industrial laser-ultrasonics, to detect ultrasound in tissues. This approach enables non-contact PAT (NCPAT) without exceeding laser exposure safety limits. The sensitivity of the method is based on the use of suitably shaped detection laser pulses and a confocal Fabry-Perot interferometer in differential configuration. Reliable image reconstruction is obtained by measuring remotely the surface profile of the tissue with an optical coherence tomography system. The proposed method also allows non-contact ultrasound imaging (US) by applying a second reconstruction algorithm to the data acquired for NCPAT. Endogenous and exogenous inclusions exhibiting optical and acoustic contrasts were detected ex vivo in chicken breast and calf brain specimens. Inclusions down to 0.3 mm in size were detected at depths exceeding 1 cm. The method could expand the scope of photoacoustic and US to in-vivo biomedical applications where contact is impractical.
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Affiliation(s)
- Guy Rousseau
- Industrial Materials Institute, National Research Council of Canada, 75 De Mortagne Boulevard, Boucherville, Québec J4B 6Y4, Canada.
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Rousseau G, Blouin A, Monchalin JP. Non-contact photoacoustic tomography and ultrasonography for tissue imaging. Biomed Opt Express 2012; 3:16-25. [PMID: 22254164 PMCID: PMC3255333 DOI: 10.1364/boe.3.000016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 10/14/2011] [Accepted: 11/22/2011] [Indexed: 05/04/2023]
Abstract
The detection of ultrasound in photoacoustic tomography (PAT) and ultrasonography (US) usually relies on ultrasonic transducers in contact with the biological tissue. This is a major drawback for important potential applications such as surgery and small animal imaging. Here we report the use of remote optical detection, as used in industrial laser-ultrasonics, to detect ultrasound in biological tissues. This strategy enables non-contact implementation of PAT and US without exceeding laser exposure safety limits. The method uses suitably shaped laser pulses and a confocal Fabry-Perot interferometer in differential configuration to reach quantum-limited sensitivity. Endogenous and exogenous inclusions exhibiting optical and acoustic contrasts were detected ex vivo in chicken breast and calf brain specimens. Inclusions down to 0.5 mm in size were detected at depths well exceeding 1 cm. The method could significantly expand the scope of applications of PAT and US in biomedical imaging.
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Lamouche G, Dufour M, Hewko M, Vergnole S, Gauthier B, Bisaillon CE, Monchalin JP, Sowa MG. Intravascular optical coherence tomography on a beating heart model. J Biomed Opt 2010; 15:046023. [PMID: 20799825 DOI: 10.1117/1.3475960] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The advantages and limitations of using a beating heart model in the development of intravascular optical coherence tomography are discussed. The model fills the gap between bench experiments, performed on phantoms and excised arteries, and whole animal in-vivo preparations. The beating heart model is stable for many hours, allowing for extended measurement times and multiple imaging sessions under in-vivo conditions without the complications of maintaining whole-animal preparation. The perfusate supplying the heart with nutrients can be switched between light scattering blood to a nonscattering perfusate to allow the optical system to be optimized without the need of an efficient blood displacement strategy. Direct access to the coronary vessels means that there is no need for x-ray fluoroscopic guidance of the catheter to the heart, as is the case in whole animal preparation. The model proves to be a valuable asset in the development of our intravascular optical coherence tomography technology.
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Affiliation(s)
- Guy Lamouche
- Conseil National de Recherches Canada, Institut des Materiaux Industriels, Boucherville, Quebec, Canada.
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Rousseau G, Blouin A, Monchalin JP. Ultrasound-modulated optical imaging using a high-power pulsed laser and a double-pass confocal Fabry-Perot interferometer. Opt Lett 2009; 34:3445-7. [PMID: 19881622 DOI: 10.1364/ol.34.003445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We report the use of short ultrasonic bursts and high-peak-power laser pulses to detect absorbing objects in thick scattering media (SMs). The detection of ultrasound-tagged photons is performed with a double-pass confocal Fabry-Perot interferometer. Photons shifted by the fundamental and harmonic frequencies of the ultrasonic bursts were observed. Absorbing objects were detected in 30- and 60-mm-thick SMs including a sample of biological tissue.
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Affiliation(s)
- Guy Rousseau
- Industrial Materials Institute, National Research Council of Canada, 75 de Mortagne Boulevard, Boucherville, Québec, Canada J4B 6Y4.
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Abstract
Ultrasound-modulated optical imaging (or tomography) is an emerging biodiagnostic technique which provides the optical spectroscopic signature and the localization of an absorbing object embedded in a strongly scattering medium. We propose to improve the sensitivity of the technique by using a pulsed single-frequency laser to raise the optical peak power applied to the scattering medium and thereby collect more ultrasonically tagged photons. Moreover, when the detection of tagged photons is done with a photorefractive interferometer, the high optical peak power reduces the response time of the photorefractive crystal below the speckle field decorrelation time. Results obtained with a GaAs photorefractive interferometer are presented for 30- and 60-mm thick scattering media.
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Affiliation(s)
- Guy Rousseau
- Industrial Materials Institute, National Research Council of Canada, Boucherville, Québec, Canada.
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Abstract
We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other fields. We present in detail the fabrication process which involves embedding silica microspheres in a silicone matrix. We also characterize the resulting phantoms with scanning electron microscopy and optical measurements. To our knowledge, no such phantoms were proposed in the literature before. Our technique has a wide range of applicability and could also be adapted to fabricate phantoms with various optical and mechanical properties.
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Affiliation(s)
- Charles-Etienne Bisaillon
- Industrial Materials Institute, National Research Council Canada, 75 de Mortagne, Boucherville, Québec J4B 6Y4, Canada.
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Blouin A, Levesque D, Neron C, Drolet D, Monchalin JP. Improved resolution and signal-to-noise ratio in laser-ultrasonics by SAFT processing. Opt Express 1998; 2:531-539. [PMID: 19381225 DOI: 10.1364/oe.2.000531] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Laser-ultrasonics is an emerging nondestructive technique using lasers for the generation and detection of ultrasound which presents numerous advantages for industrial inspection. In this paper, the problem of detection by laser-ultrasonics of small defects within a material is addressed. Experimental results obtained with laser-ultrasonics are processed using the Synthetic Aperture Focusing Technique (SAFT), yielding improved flaw detectability and spatial resolution. Experiments have been performed on an aluminum sample with a contoured back surface and two flat-bottom holes. Practical interest of coupling SAFT to laser-ultrasonics is also discussed.
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Corriveau R, Monchalin JP, Bertrand L. Photoacoustic Zeeman spectroscopy of Na(15)O with an HF chemical laser. Appl Opt 1984; 23:372-373. [PMID: 20407547 DOI: 10.1364/ao.23.000372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Bertrand L, Monchalin JP, Corriveau R. Photoacoustic measurement of water vapor and CO2 absorption coefficients at HF laser wavelengths. Appl Opt 1983; 22:3148. [PMID: 18200169 DOI: 10.1364/ao.22.003148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Bertrand L, Monchalin JP, Lepoutre F. Magnitude and phase photoacoustic spectra of chrysotile asbestos, a powdered sample. Appl Opt 1982; 21:248-252. [PMID: 20372437 DOI: 10.1364/ao.21.000248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Magnitude and phase photoacoustic spectra of a powdered sample made of chrysotile asbestos have been recorded with a low resolution grating spectrometer at ~16 Hz. A good reproduction of the true absorption spectra is obtained from the recording of the phase variation. The optical, thermal, and acoustical effects occurring within this heterogeneous sample are discussed, and a qualitative explanation of the observations is given.
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Monchalin JP, Kelly MJ, Thomas JE, Kurnit NA, Szöke A, Zernike F, Lee PH, Javan A. Accurate laser wavelength measurement with a precision two-beam scanning Michelson interferometer. Appl Opt 1981; 20:736-757. [PMID: 20309198 DOI: 10.1364/ao.20.000736] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This paper gives the details of a precision two-beam scanning Michelson interferometer, designed and perfected for accurate comparison of an unknown laser wavelength and the precisely calibrated wavelength of a reference laser. An iodine Lamb-dip stabilized He-Ne 633-nm laser (calibrated with respect to a Kr standard) is used as the reference. The design incorporates features to minimize instrumental errors and the effect of fringe shifts caused by diffraction (in the IR). It is applied to accurate measurements of a stable CO(2) laser wavelength tuned to the centers of its various transitions. Measurements are done by simultaneous fringe counting and relative fringe-phase comparison at the two wavelengths using on-line data storage and processing with an electronic digital computer. The accuracy in the 10-microm region is several parts in 10(9) and is limited by correction for diffraction fringe shifts. Because of its low-Q and broadband operating characteristics, it can be applied to rapid accurate laser wavelength measurements over the entire wavelength range permitted by its transmitting optics. In the visible range where the diffraction correction is small, the interferometer can be used to perform measurements to within several parts in 10(11). The paper gives theoretical derivation of various diffraction corrections, the design and construction of the interferometer, the alignment procedures, detailed analysis of various error sources, and data processing. It also gives the details of a previously reported accurate measurement of the speed of light using the measured wavelength of the CO(2) R(14) line and its known frequency.
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Bertrand L, Monchalin JP, Pitre R, Meyer ML, Gagné JM. Design of a compact cw chemical HF/DF laser using a microwave discharge. Rev Sci Instrum 1979; 50:708. [PMID: 18699587 DOI: 10.1063/1.1135922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A compact cw chemical HF/DF laser is described. The laser system consists of a microwave discharge using a surfatron to dissociate SF6 molecules mixed with He, a reaction chamber engineered to provide a fast mixing of reacting atoms and molecules, and an optical resonator which includes a concave mirror and a blazed grating for line selection, both mounted on a rigid Invar frame. The laser oscillates on a single line single TEM00 mode over many P transitions of HF and DF with a typical intensity fluctuation of 5% and a frequency jitter of about 30 MHz.
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Affiliation(s)
- L Bertrand
- Laboratoire d'optique et de spectroscopie, Departement de Genie Physique, Ecole Polytechnique, Campus de l'Universite de Montreal, Case Postale 6079, Succ. A Montreal, Quebec, H3C 3A7, Canada
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Monchalin JP, Kelly MJ, Thomas JE, Kurnit NA, Szoke A, Javan A, Zernike F, Lee PH. Determination of the speed of light by absolute wavelength measurement of the R(14) line of the CO2 9.4-Mum band and the known frequency of this line. Opt Lett 1977; 1:5. [PMID: 19680312 DOI: 10.1364/ol.1.000005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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