Continuous-wave ultrasonic modulation of scattered laser light to image objects in turbid media

Wang, Lihong; Jacques, Steven L.; Zhao, Xuemei

doi:10.1364/ol.20.000629

Cited by 240 publications

(165 citation statements)

References 15 publications

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“…Marks et al investigated the modulation of light in homogeneous scattering media with pulsed ultrasound [1]. Wang et al developed ultrasound-modulated optical tomography in scattering media with continuous-wave ultrasound [2]. Kempe et al showed experimentally the transition of ultrasonic modulation from the ballistic to the scattered regimes [3].…”

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confidence: 99%

Mechanisms of Ultrasonic Modulation of Multiply Scattered Coherent Light: An Analytic Model

2001

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An analytic model of the ultrasonic modulation of multiply scattered coherent light in scattering media is developed based on two mechanisms: the ultrasonic modulation of the index of refraction and the ultrasonic modulation of the displacements of Rayleigh scatterers. In water solutions, for example, the first mechanism is slightly less important than the second mechanism when the scattering mean free path is less than a critical fraction (0.0890) of the acoustic wavelength, and it becomes increasingly more important beyond this point. This model agrees well with an independent Monte Carlo model.

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confidence: 99%

Mechanisms of Ultrasonic Modulation of Multiply Scattered Coherent Light: An Analytic Model

2001

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“…The frequency shift would then move the multiply scattered light outside the frequency range of the bandpass filter. Multiple groups have investigated classical models of the interaction of sound and light in tissue, which has included Bragg and Raman-Nath Scattering mechanisms (13)(14)(15)(16)(17)(18)(19). Notable work with multiple scattering includes that of Wang, who has modeled the interaction of multiply scattered light with acoustical waves and the contribution from changes in refractive index vs. displacements of scatterers (18)(19).…”

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confidence: 99%

Ultrasound induced improvement in optical coherence tomography (OCT) resolution

Schenk

Brezinski

2002

Proc. Natl. Acad. Sci. U.S.A.

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Optical coherence tomography (OCT) is a rapidly emerging technology for high-resolution biomedical imaging. The axial resolution of this technology is determined by the bandwidth of the source. Commercial sources generally provide resolutions of 10 -20 m whereas laboratory-based solid state lasers have resolutions of Ϸ4 m. The resolution in tissue depends almost exclusively on detecting single scattered events. However, the phenomenon known as multiple scattering results in a deterioration of resolution as a function of depth. In this study, OCT was combined with ultrasound in an attempt to reduce the effect of multiple scattering. The theory is that, with parallel ultrasound and OCT beams, multiply scattered light with a momentum component significantly perpendicular to the OCT beam will be reduced because the light is Doppler shifted outside the bandpass filter of the OCT detection electronics. A 7.5-MHz ultrasound transducer was used to introduce the photon͞phonon interaction. A reflecting metal plate was placed within biological tissue, and the point spread function (PSF) was assessed off the reflector. The PSF was determined in the presence of no ultrasound, pulsed ultrasound, and continuouswave (CW) ultrasound. CW ultrasound resulted in a 17% improvement (P < 0.001) in resolution and pulsed ultrasound resulted in 8% (P < 0.01). Image noise reduction could also be noted. Combining OCT with a parallel ultrasound beam results in an improvement in resolution through a reduced effect of multiple scattering due to photon͞phonon interaction. With higher frequencies, better control of the acoustical beam, and tests in media with higher rates of multiple scattering, improved results are anticipated.multiple scattering ͉ osteoarthritis ͉ surveillance ͉ plaque rupture ͉ imaging

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“…It is well known that the scattered optical field carries information about the medium. This principle has been exploited to develop a hybrid imaging modality, known as acousto-optic imaging (AOI), which combines the spectroscopic sensitivity of optical methods with the spatial resolution of ultrasonic imaging [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. AOI holds great promise as a tool to probe hidden structure inside of highly scattering media, such as clouds, paint, and biological tissue-a problem which is of both fundamental interest and considerable applied importance [18].…”

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confidence: 99%