Abstract

Ultrasound-modulated optical tomography (UOT) detects ultrasonically modulated light to spatially localize multiply scattered photons in turbid media with the ultimate goal of imaging the optical properties in living subjects. A principal challenge of the technique is weak modulated signal strength. We discuss ways to push the limits of signal enhancement with intense acoustic bursts while conforming to optical and ultrasonic safety standards. A CCD-based speckle-contrast detection scheme is used to detect acoustically modulated light by measuring changes in speckle statistics between ultrasound-on and ultrasound-off states. The CCD image capture is synchronized with the ultrasound burst pulse sequence. Transient acoustic radiation force, a consequence of bursts, is seen to produce slight signal enhancement over pure ultrasonic-modulation mechanisms for bursts and CCD exposure times of the order of milliseconds. However, acoustic radiation-force-induced shear waves are launched away from the acoustic sample volume, which degrade UOT spatial resolution. By time gating the CCD camera to capture modulated light before radiation force has an opportunity to accumulate significant tissue displacement, we reduce the effects of shear-wave image degradation, while enabling very high signal-to-noise ratios. Additionally, we maintain high-resolution images representative of optical and not mechanical contrast. Signal-to-noise levels are sufficiently high so as to enable acquisition of 2D images of phantoms with one acoustic burst per pixel.

© 2007 Optical Society of America

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  1. F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
    [CrossRef]
  2. W. Leutz and G. Maret, "Ultrasonic modulation of multiply scattered coherent light," Physica B 204, 14-19 (1995).
    [CrossRef]
  3. L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: an analytic model," Phys. Rev. Lett. 87, 043903 (2001).
    [CrossRef] [PubMed]
  4. L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: a Monte Carlo model," Opt. Lett. 26, 1191-1193 (2001).
    [CrossRef]
  5. S. Sakadzic and L. H. Wang, "Ultrasonic modulation of multiply scattered coherent light: an analytical model for anisotropically scattering media," Phys. Rev. E 66, 1-9 (2002).
  6. S. Sakadzic and L. H. Wang, "Modulation of multiply scattered coherent light by ultrasonic pulses: an analytic model," Phys. Rev. E 72, 036620 (2005).
  7. S. Lévêque, A. C. Boccara, M. Lebec, and H. Saint-Jalmes, "Ultrasonic tagging of photon paths in scattering media: parallel speckle modulation processing," Opt. Lett. 24, 181-183 (1999).
    [CrossRef]
  8. J. Li, G. Ku, and L. H. Wang, "Ultrasound-modulated optical tomography of biological tissue by use of contrast of laser speckles," Appl. Opt. 41, 6030-6035 (2002).
    [CrossRef] [PubMed]
  9. M. Kempe, M. Larionov, D. Zaslavsky, and A. Z. Genack, "Acousto-optic tomography with multiply scattered light," J. Opt. Soc. Am. A 14, 1151-1158 (1997).
    [CrossRef]
  10. J. Li and L. H. Wang, "Methods for parallel-detection-based ultrasound-modulated optical tomography," Appl. Opt. 41, 2079-2084 (2002).
    [CrossRef] [PubMed]
  11. S. Sakadzic and L. H. Wang, "High-resolution ultrasound-modulated optical tomography in biological tissues," Opt. Lett. 29, 2770-2772 (2004).
    [CrossRef] [PubMed]
  12. F. Ramaz, B. C. Forget, M. Atlan, and A. C. Boccara, "Photorefractive detection of tagged photons in ultrasound modulated optical tomography of thick biological tissues," Opt. Express 12, 5469-5474 (2004).
    [CrossRef] [PubMed]
  13. T. W. Murray, L. Sui, G. Maguluri, R. A. Roy, A. Nieva, F. Blonigen, and C. A. DiMarzio, "Detection of ultrasound-modulated photons in diffuse media using the photo-refractive effect," Opt. Lett. 29, 2509-2511 (2004).
    [CrossRef] [PubMed]
  14. R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
    [CrossRef]
  15. A. Lev and B. G. Sfez, "Pulsed ultrasound-modulated light tomography," Opt. Lett. 28, 1549-1551 (2003).
    [CrossRef] [PubMed]
  16. K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
    [CrossRef] [PubMed]
  17. C. Kim, R. J. Zemp, and L. H. Wang, "Intense acoustic bursts as a signal-enhancement mechanism in ultrasound-modulated optical tomography," Opt. Lett. 31, 2423-2425 (2006).
    [CrossRef] [PubMed]
  18. M. Fatemi and J. F. Greenleaf, "Vibro-acoustography: an imaging modality based on ultrasound-stimulated acoustic emission," Proc. Natl. Acad. Sci. USA 96, 6603-6608 (1999).
    [CrossRef] [PubMed]
  19. K. R. Nightingale, "Shear wave generation using acoustic radiation force: in vivo and ex vivo results," Ultrasound Med. Biol. 29, 1715-1723 (2003).
    [CrossRef] [PubMed]
  20. A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
    [CrossRef]
  21. J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
    [PubMed]
  22. L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
    [CrossRef] [PubMed]
  23. G. Marquez and L. H. Wang, "White light oblique incidence reflectometer for measuring absorption and reduced scattering spectra of tissue-like turbid media," Opt. Express 1, 454-460 (1997).
    [CrossRef] [PubMed]
  24. S. Chen, "Shear property characterization of viscoelastic media using vibrations induced by ultrasound radiation force," Ph.D. dissertation (Mayo Graduate School, 2002).
  25. Z136.1 ANSI Standard For the Safe Use of Lasers (American National Standards Institute, 2000).
  26. AIUM/National Electrical Manufacturers Association, Standard for Real-Time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment (American Institute of Ultrasound in Medicine, 2004).
    [PubMed]

2006 (2)

R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
[CrossRef]

C. Kim, R. J. Zemp, and L. H. Wang, "Intense acoustic bursts as a signal-enhancement mechanism in ultrasound-modulated optical tomography," Opt. Lett. 31, 2423-2425 (2006).
[CrossRef] [PubMed]

2005 (1)

S. Sakadzic and L. H. Wang, "Modulation of multiply scattered coherent light by ultrasonic pulses: an analytic model," Phys. Rev. E 72, 036620 (2005).

2004 (4)

2003 (2)

K. R. Nightingale, "Shear wave generation using acoustic radiation force: in vivo and ex vivo results," Ultrasound Med. Biol. 29, 1715-1723 (2003).
[CrossRef] [PubMed]

A. Lev and B. G. Sfez, "Pulsed ultrasound-modulated light tomography," Opt. Lett. 28, 1549-1551 (2003).
[CrossRef] [PubMed]

2002 (4)

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

S. Sakadzic and L. H. Wang, "Ultrasonic modulation of multiply scattered coherent light: an analytical model for anisotropically scattering media," Phys. Rev. E 66, 1-9 (2002).

J. Li and L. H. Wang, "Methods for parallel-detection-based ultrasound-modulated optical tomography," Appl. Opt. 41, 2079-2084 (2002).
[CrossRef] [PubMed]

J. Li, G. Ku, and L. H. Wang, "Ultrasound-modulated optical tomography of biological tissue by use of contrast of laser speckles," Appl. Opt. 41, 6030-6035 (2002).
[CrossRef] [PubMed]

2001 (2)

L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: an analytic model," Phys. Rev. Lett. 87, 043903 (2001).
[CrossRef] [PubMed]

L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: a Monte Carlo model," Opt. Lett. 26, 1191-1193 (2001).
[CrossRef]

1999 (2)

S. Lévêque, A. C. Boccara, M. Lebec, and H. Saint-Jalmes, "Ultrasonic tagging of photon paths in scattering media: parallel speckle modulation processing," Opt. Lett. 24, 181-183 (1999).
[CrossRef]

M. Fatemi and J. F. Greenleaf, "Vibro-acoustography: an imaging modality based on ultrasound-stimulated acoustic emission," Proc. Natl. Acad. Sci. USA 96, 6603-6608 (1999).
[CrossRef] [PubMed]

1998 (1)

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

1997 (2)

1995 (1)

W. Leutz and G. Maret, "Ultrasonic modulation of multiply scattered coherent light," Physica B 204, 14-19 (1995).
[CrossRef]

1993 (1)

F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
[CrossRef]

1976 (1)

L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
[CrossRef] [PubMed]

Atlan, M.

Bercoff, J.

J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
[PubMed]

Blonigen, F.

Boccara, A. C.

Brooksby, G. W.

F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
[CrossRef]

Carstensen, E. L.

L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
[CrossRef] [PubMed]

Chen, S.

S. Chen, "Shear property characterization of viscoelastic media using vibrations induced by ultrasound radiation force," Ph.D. dissertation (Mayo Graduate School, 2002).

DiMarzio, C. A.

Dyro, J. F.

L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
[CrossRef] [PubMed]

Emelianov, S. Y.

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Fatemi, M.

M. Fatemi and J. F. Greenleaf, "Vibro-acoustography: an imaging modality based on ultrasound-stimulated acoustic emission," Proc. Natl. Acad. Sci. USA 96, 6603-6608 (1999).
[CrossRef] [PubMed]

Fink, M.

J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
[PubMed]

Forget, B. C.

Fowlkes, B. J.

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Frizzell, L. A.

L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
[CrossRef] [PubMed]

Genack, A. Z.

Greenleaf, J. F.

M. Fatemi and J. F. Greenleaf, "Vibro-acoustography: an imaging modality based on ultrasound-stimulated acoustic emission," Proc. Natl. Acad. Sci. USA 96, 6603-6608 (1999).
[CrossRef] [PubMed]

Kempe, M.

Kim, C.

Ku, G.

Larionov, M.

Lebec, M.

Leutz, W.

W. Leutz and G. Maret, "Ultrasonic modulation of multiply scattered coherent light," Physica B 204, 14-19 (1995).
[CrossRef]

Lev, A.

Lévêque, S.

Li, J.

Maguluri, G.

Maret, G.

W. Leutz and G. Maret, "Ultrasonic modulation of multiply scattered coherent light," Physica B 204, 14-19 (1995).
[CrossRef]

Marks, F. A.

F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
[CrossRef]

Marquez, G.

Murray, T. W.

Nieva, A.

Nightingale, K. R.

K. R. Nightingale, "Shear wave generation using acoustic radiation force: in vivo and ex vivo results," Ultrasound Med. Biol. 29, 1715-1723 (2003).
[CrossRef] [PubMed]

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

Nightingale, R. W.

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

Pernot, M.

J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
[PubMed]

Ramaz, F.

Roy, R. A.

Rudenko, O. V.

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Saint-Jalmes, H.

Sakadzic, S.

S. Sakadzic and L. H. Wang, "Modulation of multiply scattered coherent light by ultrasonic pulses: an analytic model," Phys. Rev. E 72, 036620 (2005).

S. Sakadzic and L. H. Wang, "High-resolution ultrasound-modulated optical tomography in biological tissues," Opt. Lett. 29, 2770-2772 (2004).
[CrossRef] [PubMed]

S. Sakadzic and L. H. Wang, "Ultrasonic modulation of multiply scattered coherent light: an analytical model for anisotropically scattering media," Phys. Rev. E 66, 1-9 (2002).

Sakadžic, S.

R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
[CrossRef]

Sarvazyan, A. P.

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Sfez, B. G.

Soo, M. S.

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

Sui, L.

Swanson, S. D.

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Tanter, M.

J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
[PubMed]

Tomlinson, H. W.

F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
[CrossRef]

Trahey, G. E.

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

Wang, L. H.

C. Kim, R. J. Zemp, and L. H. Wang, "Intense acoustic bursts as a signal-enhancement mechanism in ultrasound-modulated optical tomography," Opt. Lett. 31, 2423-2425 (2006).
[CrossRef] [PubMed]

R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
[CrossRef]

S. Sakadzic and L. H. Wang, "Modulation of multiply scattered coherent light by ultrasonic pulses: an analytic model," Phys. Rev. E 72, 036620 (2005).

S. Sakadzic and L. H. Wang, "High-resolution ultrasound-modulated optical tomography in biological tissues," Opt. Lett. 29, 2770-2772 (2004).
[CrossRef] [PubMed]

J. Li, G. Ku, and L. H. Wang, "Ultrasound-modulated optical tomography of biological tissue by use of contrast of laser speckles," Appl. Opt. 41, 6030-6035 (2002).
[CrossRef] [PubMed]

J. Li and L. H. Wang, "Methods for parallel-detection-based ultrasound-modulated optical tomography," Appl. Opt. 41, 2079-2084 (2002).
[CrossRef] [PubMed]

S. Sakadzic and L. H. Wang, "Ultrasonic modulation of multiply scattered coherent light: an analytical model for anisotropically scattering media," Phys. Rev. E 66, 1-9 (2002).

L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: an analytic model," Phys. Rev. Lett. 87, 043903 (2001).
[CrossRef] [PubMed]

L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: a Monte Carlo model," Opt. Lett. 26, 1191-1193 (2001).
[CrossRef]

G. Marquez and L. H. Wang, "White light oblique incidence reflectometer for measuring absorption and reduced scattering spectra of tissue-like turbid media," Opt. Express 1, 454-460 (1997).
[CrossRef] [PubMed]

Zaslavsky, D.

Zemp, R. J.

R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
[CrossRef]

C. Kim, R. J. Zemp, and L. H. Wang, "Intense acoustic bursts as a signal-enhancement mechanism in ultrasound-modulated optical tomography," Opt. Lett. 31, 2423-2425 (2006).
[CrossRef] [PubMed]

Appl. Opt. (2)

J. Acoust. Soc. Am. (1)

L. A. Frizzell, E. L. Carstensen, and J. F. Dyro, "Shear properties of mammalian tissues at low megahertz frequencies," J. Acoust. Soc. Am. 60, 1409-1411 (1976).
[CrossRef] [PubMed]

J. Opt. Soc. Am. A (1)

Opt. Express (2)

Opt. Lett. (6)

Phys. Rev. E (3)

S. Sakadzic and L. H. Wang, "Ultrasonic modulation of multiply scattered coherent light: an analytical model for anisotropically scattering media," Phys. Rev. E 66, 1-9 (2002).

S. Sakadzic and L. H. Wang, "Modulation of multiply scattered coherent light by ultrasonic pulses: an analytic model," Phys. Rev. E 72, 036620 (2005).

R. J. Zemp, S. Sakadžić, and L. H. Wang, "Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography," Phys. Rev. E 73, 061920 (2006).
[CrossRef]

Phys. Rev. Lett. (1)

L. H. Wang, "Mechanisms of ultrasonic modulation of multiply scattered coherent light: an analytic model," Phys. Rev. Lett. 87, 043903 (2001).
[CrossRef] [PubMed]

Physica B (1)

W. Leutz and G. Maret, "Ultrasonic modulation of multiply scattered coherent light," Physica B 204, 14-19 (1995).
[CrossRef]

Proc. Natl. Acad. Sci. USA (1)

M. Fatemi and J. F. Greenleaf, "Vibro-acoustography: an imaging modality based on ultrasound-stimulated acoustic emission," Proc. Natl. Acad. Sci. USA 96, 6603-6608 (1999).
[CrossRef] [PubMed]

Proc. SPIE (1)

F. A. Marks, H. W. Tomlinson, and G. W. Brooksby, "Comprehensive approach to breast cancer detection using light: photon localization by ultrasound modulation and tissue characterization by spectral discrimination," in Photon Migration and Imaging in Random Media and Tissue, B. Chance and R. R. Alfano, eds., Proc. SPIE 1888, 500-510 (1993).
[CrossRef]

Ultrason. Imaging (1)

J. Bercoff, M. Pernot, M. Tanter, and M. Fink, "Monitoring thermally-induced lesions with supersonic shear imaging," Ultrason. Imaging 26, 71-84 (2004).
[PubMed]

Ultrasound Med. Biol. (3)

K. R. Nightingale, M. S. Soo, R. W. Nightingale, and G. E. Trahey, "Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility," Ultrasound Med. Biol. 28, 227-235 (2002).
[CrossRef] [PubMed]

K. R. Nightingale, "Shear wave generation using acoustic radiation force: in vivo and ex vivo results," Ultrasound Med. Biol. 29, 1715-1723 (2003).
[CrossRef] [PubMed]

A. P. Sarvazyan, O. V. Rudenko, S. D. Swanson, B. J. Fowlkes, and S. Y. Emelianov, "Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics," Ultrasound Med. Biol. 24, 1419-1435 (1998).
[CrossRef]

Other (3)

S. Chen, "Shear property characterization of viscoelastic media using vibrations induced by ultrasound radiation force," Ph.D. dissertation (Mayo Graduate School, 2002).

Z136.1 ANSI Standard For the Safe Use of Lasers (American National Standards Institute, 2000).

AIUM/National Electrical Manufacturers Association, Standard for Real-Time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment (American Institute of Ultrasound in Medicine, 2004).
[PubMed]

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Figures (8)

Fig. 1
Fig. 1

Shear-wave attenuation coefficients as a function of cw shear-wave frequencies. The three curves are plotted for viscosities of 0.1, 1, and 10 Pa s.

Fig. 2
Fig. 2

(a) Shear displacement as a function of radius and time during and after a 2 ms acoustic burst. (b) Normalized shear displacement as a function of radial distance for various times after initiation of a 2 ms burst. Model parameters for both (a) and (b): Transducer aperture: a = 12.5   mm , focal distance: d = 38   mm , shear-wave speed: c t = 4 m / s , viscosity: η = 0.5 Pa s, speed of sound: c = 1500 m / s , acoustic frequency: f o = 1   MHz , density: ρ = 1035 kg / m 3 , burst duration = 2 ms, pressure: P o = 1 MPa. These parameters were selected to match conditions for experiments in Section 3.

Fig. 3
Fig. 3

Experimental setup: FG, function generator; TG, trigger generator; Tx, ultrasound transducer; S, sample.

Fig. 4
Fig. 4

Change in speckle contrast versus CCD trigger delay for (a) 2 ms CCD exposure time and (b) 0.2 ms CCD exposure time.

Fig. 5
Fig. 5

Radiation-force-weighted image quality degradation as a function of increasing ultrasound pressure. The vertical axis is the measured change in speckle contrast Δ C between ultrasound-on and ultrasound-off-states, which has been shifted and normalized to map to a scale of 0 to 1 [i.e., ( Δ C Δ C min ) / ( Δ C max Δ C min ) ]. The x axis is the lateral position. The two dips representing two absorbing objects become less distinguishable for higher acoustic pressures.

Fig. 6
Fig. 6

Longer exposure times degrade the spatial resolution and image contrast due to integration of signal from nonlocalized shear-wave-induced displacements. Shorter-exposure times are advantageous in this regard and exhibit higher CNRs.

Fig. 7
Fig. 7

Comparison of 1D UOT images using 0.3 and 1.9 MPa pressures for short 0.2 ms CCD exposure times.

Fig. 8
Fig. 8

(Color online) (a) Two-dimensional UOT image of a phantom with two absorbing objects to be compared with a photograph of the cross section of the phantom, shown in (b), which was cut open at the imaging plane after the UOT experiments. No averaging was used. We used intense 1.5 MPa bursts and CCD exposure time synchronized with the burst period.

Tables (2)

Tables Icon

Table 1 Image Quality Figures of Merit as a Function of CCD Exposure Time

Tables Icon

Table 2 Short-Exposure-Time Image Quality Figures of Merit

Equations (8)

Equations on this page are rendered with MathJax. Learn more.

C = σ I ¯ s p ,
F = d r S E t ,
c t = μ / ρ ,
2 s x t 2 ( c t 2 + ν t ) s x = F x ,
s x ( r , t ) = 0 s ˜ ( β , t ) J o ( β r ) β d β ,
d 2 s ˜ d t 2 + β 2 ν d s ˜ d t + β 2 c t 2 s ˜ = F ˜ x ( x , β , t ) .
G ( t , t ) = H ( t t ) e β 2 ν ( t t ) / 2 β 2 c t 2 β 4 ν 4 / 4 × sin [ ( t t ) β 2 c t 2 β 4 ν 4 / 4 ] ,
CNR = Δ C max Δ C min σ Δ C ,

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