Cost-effective assembly of a basic fiber-optic hydrophone for measurement of high-amplitude therapeutic ultrasound fields

Parsons, Jessica E.; Cain, Charles A.; Fowlkes, J. Brian

doi:10.1121/1.2166708

Cited by 220 publications

(147 citation statements)

References 18 publications

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“…27 The hydrophone's frequency response was calibrated by substitution comparison with a reference piezoelectric hydrophone (HGL-0085, Onda Corporation, Sunnyvale, CA). The measured waveforms were corrected using a deconvolution procedure to account for the frequency response of the hydrophone.…”

Section: A Experimental Apparatusmentioning

confidence: 99%

Cavitation clouds created by shock scattering from bubbles during histotripsy

Maxwell

Wang

Cain

et al. 2011

The Journal of the Acoustical Society of America

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277

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Histotripsy is a therapy that focuses short-duration, high-amplitude pulses of ultrasound to incite a localized cavitation cloud that mechanically breaks down tissue. To investigate the mechanism of cloud formation, high-speed photography was used to observe clouds generated during single histotripsy pulses. Pulses of 5À20 cycles duration were applied to a transparent tissue phantom by a 1-MHz spherically focused transducer. Clouds initiated from single cavitation bubbles that formed during the initial cycles of the pulse, and grew along the acoustic axis opposite the propagation direction. Based on these observations, we hypothesized that clouds form as a result of large negative pressure generated by the backscattering of shockwaves from a single bubble. The positive-pressure phase of the wave inverts upon scattering and superimposes on the incident negativepressure phase to create this negative pressure and cavitation. The process repeats with each cycle of the incident wave, and the bubble cloud elongates toward the transducer. Finite-amplitude propagation distorts the incident wave such that the peak-positive pressure is much greater than the peak-negative pressure, which exaggerates the effect. The hypothesis was tested with two modified incident waves that maintained negative pressure but reduced the positive pressure amplitude. These waves suppressed cloud formation which supported the hypothesis.

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Section: A Experimental Apparatusmentioning

confidence: 99%

Cavitation clouds created by shock scattering from bubbles during histotripsy

Maxwell

Wang

Cain

et al. 2011

The Journal of the Acoustical Society of America

Self Cite

277

258

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“…The sensing area is the end of a clean, cleaved optical fiber (ø100 µm) inserted directly into the hydrogel from the top surface and angled towards the aluminum plate. We employ a custombuilt FOPH based on the design reported by Parsons and Fowlkes, 20 and suitable performance was verified using calibrated oils as described by Arvengas. 21 The FOPH laser is a 1000 mW fiber-pigtailed diode laser with a center wavelength of 860 nm and 3.1 nm spectral width (QPhotonics QLFD-850-1000M), and the detector is a 150 MHz broadband avalanche photo-detector (Thorlabs PDA10A) with a rise time of 2.3 ns.…”

Section: Experimental Methodologymentioning

confidence: 99%

“…20 In this work, we use the Tait equation as a first approximation but, because shock velocity is known from the high-speed images, density can be converted to pressure by using conservation of mass and momentum,…”

Section: Experimental Methodologymentioning

confidence: 99%

“…20 Typically, density is then converted to pressure using an equation of state for the material. For water, the equation of state commonly used is the Tait equation,…”

Section: Experimental Methodologymentioning

confidence: 99%

“…12,17,18 Density can be inferred non-invasively using wave reverberation 3,13 or by inserting a probe such as the fiber-optic probe hydrophone (FOPH). [19][20][21] In this work, a single-stage LGG is employed to generate shock waves in a solid block of hydrogel. We measure U s and planarity of the shock front in the hydrogel using high-speed Schlieren photography.…”

Section: Introductionmentioning

confidence: 99%

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Characterizing shock waves in hydrogel using high speed imaging and a fiber-optic probe hydrophone

Anderson

Betney

Doyle³

et al. 2017

Physics of Fluids

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The impact of a stainless steel disk-shaped projectile launched by a single-stage light gas gun is used to generate planar shock waves with amplitudes on the order of 102MPa in a hydrogel target material. These shock waves are characterized using ultra-high-speed imaging as well as a fiber-optic probe hydrophone. Although the hydrogel equation of state (EOS) is unknown, the combination of these measurements with conservation of mass and momentum allows us to calculate pressure. It is also shown that although the hydrogel behaves similarly to water, the use of a water EOS underpredicts pressure amplitudes in the hydrogel by ∼10% at the shock front. Further, the water EOS predicts pressures approximately 2% higher than those determined by conservation laws for a given value of the shock velocity. Shot to shot repeatability is controlled to within 10%, with the shock speed and pressure increasing as a function of the velocity of the projectile at impact. Thus the projectile velocity may be used as an adequate predictor of shock conditions in future work with a restricted suite of diagnostics.

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RF and Microwave Photonics in Biomedical Applications

Iezekiel

2009

Microwave Photonics

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In the last 20 years the field of microwave photonics has evolved due to unique features of analogue fibre-optic systems and its applications in radio over fibre for telecommunications [1] and optically controlled phased array antennas [2] for military applications, as has been discussed in earlier chapters of this book. Recently, microwave photonics techniques have also been extended to biomedical systems and this chapter presents two distinctive biomedical imaging applications that employ these techniques. (Optics already lends its application to laser Doppler anemometry, optical biopsy and optical molecular imaging, and phase microscopy.) The first application to be discussed is the design and implementation of optical hydrophone for calibration of ultrasound transducers for frequencies up to 100 MHz, which has found applications in sub-millimeter wave imaging and therapeutic applications. The second is the use of broadband modulated near infrared (NIR) light waves for quantifying blood flow and cellular functionality using spectroscopy, which is to be applied to coagulation monitoring and functional imaging with sub-centimetre spatial resolution using photon density waves. Both techniques are first discussed in terms of the fundamental physical interaction of lightwaves with biological tissues and the technical advantages that RF and microwave photonics could bring to conventional imaging modalities. Introduction to Optical HydrophoneOnly a decade ago, the highest ultrasound imaging frequency was of the order of 7 MHz. Today, modern diagnostic machines, particularly those designed for applications such as dermatology, ophthalmology and microsurgery, operate at centre frequencies close to 15 or 20 MHz [3].

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Cost-effective assembly of a basic fiber-optic hydrophone for measurement of high-amplitude therapeutic ultrasound fields

Cited by 220 publications

References 18 publications

Cavitation clouds created by shock scattering from bubbles during histotripsy

Cavitation clouds created by shock scattering from bubbles during histotripsy

Characterizing shock waves in hydrogel using high speed imaging and a fiber-optic probe hydrophone

RF and Microwave Photonics in Biomedical Applications

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