Optoacoustic generation of high frequency sound for 3-D ultrasonic imaging in medicine

O’Donnell, Matthew; Hou, Yuting; Kim, J.-S.; Ashkenazi, Shai; Huang, Sheng‐Wen; Guo, L. Jay

doi:10.1140/epjst/e2008-00392-9

Cited by 17 publications

(13 citation statements)

References 10 publications

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“…As an emerging technology, optical generation of ultrasound has been actively investigated over decades to develop transmitters, employing pulsed laser irradiation onto optical absorbers. [1][2][3][4][5] This enables nonresonant generation of ultrasound pulses with high-frequency and broadband spectra (e.g. several tens of MHz for a laser pulse width of 5-10 ns) and non-contact definition of a transmitter element by a laser spot.…”

Section: Introductionmentioning

confidence: 99%

“…several tens of MHz for a laser pulse width of 5-10 ns) and non-contact definition of a transmitter element by a laser spot. 2,3 From optoacoustic transmitters, high-frequency components up to 57 MHz have been produced and used for ultrasound imaging of microscale features. 5 Recently, focal transmitters with a 15 MHz center frequency have been demonstrated for laser-generated focused ultrasound (LGFU) that enables micro-ultrasonic treatment for high-precision therapy, [6][7][8] controlled single-bubble generation, 9 and micro-droplet ejection.…”

Section: Introductionmentioning

confidence: 99%

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Nano-structural characteristics of carbon nanotube–polymer composite films for high-amplitude optoacoustic generation

Baac

Lee

et al. 2015

Nanoscale

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We demonstrate nano-structural characteristics of carbon nanotube (CNT)-polydimethylsiloxane (PDMS) composite films that can be used as highly efficient and robust ultrasound transmitters for diagnostic and therapeutic applications. An inherent architecture of the nano-composite provides unique thermal, optical, and mechanical properties that are accommodated not just for efficient energy conversion but also for extraordinary robustness against pulsed laser ablation. First, we explain a thermoacoustic transfer mechanism within the nano-composite. CNT morphologies are examined to determine a suitable arrangement for heat transfer to the surrounding PDMS. Next, we introduce an approach to enhance optical extinction of the composite films, which uses shadowed deposition of a thin Au layer through an as-grown CNT network. Finally, the transmitter robustness is quantified in terms of laser-induced damage threshold. This reveals that the CNT-PDMS films can withstand an order-of-magnitude higher optical fluence (and extinction) than a Cr film used as a reference. Such robustness is crucial to increase the maximum-available optical energy for optoacoustic excitation and pressure generation. All of these structure-originated characteristics manifest the CNT-PDMS composite films as excellent optoacoustic transmitters for high-amplitude and high-frequency ultrasound generation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nano-structural characteristics of carbon nanotube–polymer composite films for high-amplitude optoacoustic generation

Baac

Lee

et al. 2015

Nanoscale

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“…This is commonly achieved by opaque light absorbing films or structures as e.g. metal thin films [6], light absorbing polymer thin films [7,8], optically absorbing gold nano structures [9,10], or thin layers of carbon nanotube composites [11].…”

Section: Introductionmentioning

confidence: 99%

Analytical one-dimensional model for laser-induced ultrasound in planar optically absorbing layer

2014

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Ultrasound generated by means of laser-based photoacoustic principles are in common use today and applications can be found both in biomedical diagnostics, non-destructive testing and materials characterisation. For certain measurement applications it could be beneficial to shape the generated ultrasound regarding spectral properties and temporal profile. To address this, we studied the generation and propagation of laser-induced ultrasound in a planar, layered structure. We derived an analytical expression for the induced pressure wave, including different physical and optical properties of each layer. A Laplace transform approach was employed in analytically solving the resulting set of photoacoustic wave equations. The results correspond to simulations and were compared to experimental results. To enable the comparison between recorded voltage from the experiments and the calculated pressure we employed a system identification procedure based on physical properties of the ultrasonic transducer to convert the calculated acoustic pressure to voltages. We found reasonable agreement between experimentally obtained voltages and the voltages determined from the calculated acoustic pressure, for the samples studied. The system identification procedure was found to be unstable, however, possibly from violations of material isotropy assumptions by film adhesives and coatings in the experiment. The presented analytical model can serve as a basis when addressing the inverse problem of shaping an acoustic pulse from absorption of a laser pulse in a planar layered structure of elastic materials.

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“…The conversion is through the thermoelastic process of heating leading to a corresponding pressure wave. This laser-induced ultrasound can be made broadband and of high frequency [3]. However, the conversion efficiency has been low, with low transmitted power [4].…”

Section: Introductionmentioning

confidence: 99%

Combined physical and statistical modeling of laser induced ultrasound signals from thin light absorbing films

Svanström

Linder

Carlson

2013

2013 IEEE International Ultrasonics Symposium (IUS)

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Abstract-This paper presents a method for predicting the ultrasound pulses generated by thin semi-transparent polymer films, excited by a short laser pulse. The acoustic pressure is first modeled based on the physical properties of the polymer. Partial Least-Squares Regression is then used to link the model pressure to the ultrasound pulses measured by an ultrasound transducer. The uncertainty of the regression is also simulated, showing that the method is robust to noise in the measurements.

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Optoacoustic generation of high frequency sound for 3-D ultrasonic imaging in medicine

Cited by 17 publications

References 10 publications

Nano-structural characteristics of carbon nanotube–polymer composite films for high-amplitude optoacoustic generation

Nano-structural characteristics of carbon nanotube–polymer composite films for high-amplitude optoacoustic generation

Analytical one-dimensional model for laser-induced ultrasound in planar optically absorbing layer

Combined physical and statistical modeling of laser induced ultrasound signals from thin light absorbing films

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