Quantitative measurement of ultrasound pressure field by optical phase contrast method and acoustic holography

Oyama, Seiji; Yasuda, Jun; Hanayama, H.; Yoshizawa, Shin; Umemura, Shin Ichiro

doi:10.7567/jjap.55.07kb09

Cited by 11 publications

(16 citation statements)

References 32 publications

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“…17,18) Studies on deflection of light in an ultrasound field were also started from the beginning of ultrasound research, 19,20) and various techniques that apply the phenomenon for visualization of an ultrasound field have been investigated. [21][22][23][24][25] Schlieren is a technique widely used for this purpose, but we proposed another technique called focused shadowgraphy. 26) The technique can be realized using a simple optics consisting of an illuminating light source and camera, and its usefulness in the field of medical ultrasound has been confirmed.…”

Section: Introductionmentioning

confidence: 99%

Visualization of wall propagation and surface reflection effects on ultrasound fields generated inside a small container

Aikawa

Kudo

2019

Jpn. J. Appl. Phys.

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In studies on the bioeffects of ultrasound exposure on cells cultured in a Petri dish, an understanding of the pressure field generated inside the dish is essential to achieve better dosimetry of ultrasound exposure. In this study, ultrasound fields generated inside four types of small containers designed to mimic a Petri dish were visualized using the focused shadowgraphy technique. The results revealed that wall propagation and water surface reflection of ultrasound make a complex standing wave field in the entire space of the container, which is very different from a standing wave field predicted by a simple model with reflection at the flat water surface without wall propagation.

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Section: Introductionmentioning

confidence: 99%

Visualization of wall propagation and surface reflection effects on ultrasound fields generated inside a small container

Aikawa

Kudo

2019

Jpn. J. Appl. Phys.

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“…We have already proposed a method using the optical measurement in combination with nonlinear acoustic holography. 23) In a previous study, however, the optical measurement of the time history of spatial 2D data required a long time, resulting in the reduction in measurement time, which was only about an order of magnitude compared with that in hydrophone scanning. In this study, we propose a new method using spatial 3D pressure data as the input.…”

Section: Introductionmentioning

confidence: 92%

“…Although optical measurement methods [14][15][16][17][18][19][20][21][22][23][24][25] are fast and have no risk of disturbing the field, such conventional methods are qualitative. [16][17][18] However, they can be improved to be quantitative enough to measure a 3D pressure field by combining them with a computed tomography (CT) algorithm 26) in a very short time.…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of ultrasonic pressure field using combination of optical phase contrast and nonlinear acoustic holography methods

Nakamura

Iwasaki

Yoshizawa

et al. 2018

Jpn. J. Appl. Phys.

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Ultrasound has been widely used in medicine for both diagnosis and therapeutics. To assure its safety and efficacy, it is necessary to establish a fast and accurate method of measuring an ultrasonic field. Hydrophone scanning, which is a standard method for pressure measurement, requires a long measurement time and may disturb the field. In this study, an optical phase contrast method is combined with an acoustic holography method with nonlinear propagation simulation. The nonaxisymmetric pressure field of pulse ultrasound upstream of the focus was measured by the optical phase contrast method combined with a computed tomography (CT) algorithm, and the entire three-dimensional pressure field was reconstructed by acoustic holography. The result obtained by the proposed method agreed well with that by the hydrophone measurement without absolute pressure calibration and confirmed the markedly reduced required measurement time.

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“…Through projection images can be obtained in real time, but do not give quantitative information. More recently, a quantitative tomographic optical phase contrast measurement method has been described in [24]. However, due to difficulties with optical phase unwrapping, the acoustic pressure amplitude that can currently be measured using this approach is reported to be less than 10 MPa.…”

Section: B Field Scanning Techniquesmentioning

confidence: 99%

Rapid Spatial Mapping of Focused Ultrasound Fields Using a Planar Fabry–Pérot Sensor

Martin

Zhang

Guggenheim

et al. 2017

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Measurement of high acoustic pressures is necessary in order to fully characterize clinical high-intensity focused ultrasound (HIFU) fields, and for accurate validation of computational models of ultrasound propagation. However, many existing measurement devices are unable to withstand the extreme pressures generated in these fields, and those that can often exhibit low sensitivity. Here, a planar Fabry-Pérot interferometer with hard dielectric mirrors and spacer was designed, fabricated, and characterized, and its suitability for measurement of nonlinear focused ultrasound fields was investigated. The noise equivalent pressure (NEP) of the scanning system scaled with the adjustable pressure detection range between 49 kPa for pressures up to 8 MPa and 152 kPa for measurements up to 25 MPa, over a 125 MHz measurement bandwidth. Measurements of the frequency response of the sensor showed that it varied by less than 3 dB in the range 1-62 MHz. The effective element size of the sensor was 65 and waveforms were acquired at a rate of 200 Hz. The device was used to measure the acoustic pressure in the field of a 1.1 MHz single-element spherically focused bowl transducer. Measurements of the acoustic field at low pressures compared well with measurements made using a Polyvinylidene difluoride needle hydrophone. At high pressures, the measured peak focal pressures agreed well with the focal pressure modeled using the Khokhlov-Zabolotskaya-Kuznetsov equation. Maximum peak positive pressures of 25 MPa and peak negative pressures of 12 MPa were measured, and planar field scans were acquired in scan times on the order of 1 min. The properties of the sensor and scanning system are well suited to measurement of nonlinear focused ultrasound fields, in both the focal region and the low-pressure peripheral regions. The fast acquisition speed of the system and its low NEP are advantageous, and with further development of the sensor, it has potential in application to HIFU metrology.

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Quantitative measurement of ultrasound pressure field by optical phase contrast method and acoustic holography

Cited by 11 publications

References 32 publications

Visualization of wall propagation and surface reflection effects on ultrasound fields generated inside a small container

Visualization of wall propagation and surface reflection effects on ultrasound fields generated inside a small container

Quantitative measurement of ultrasonic pressure field using combination of optical phase contrast and nonlinear acoustic holography methods

Rapid Spatial Mapping of Focused Ultrasound Fields Using a Planar Fabry–Pérot Sensor

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