Comparison of Light Spot Hydrophone (LSHD) and Fiber Optic Probe Hydrophone (FOPH) for Lithotripter Field Characterization

Leitão, Victor A.; Simmons, W. Neal; Zhou, Yufeng; Qin, Jun Qi; Sankin, Georgy; Cocks, F. H.; Fehre, Jens; Granz, B.; Nanke, Ralf; Preminger, Glenn M.; Zhong, Pei

doi:10.1063/1.2723600

Cited by 3 publications

(6 citation statements)

References 2 publications

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“…Photodetector saturation from inertial bubble growth at the fiber tip is a well documented artifact in FOPH shock wave measurements. 18,27,31,41,42 Similar interference by inertial bubbles was observed near the LSHD laser spot. Hydrophone measurements of Fig.…”

Section: Bubble At Laser Spotsupporting

confidence: 55%

“…Previous studies comparing optical probe hydrophones with the LSHD do not discuss this effect, though it may be seen when measurements are normalized to ambient pressure. 14,31 As shown in Fig. 3(b) and Table II, LSHD measurements of tensile pulse duration (t -) and secondary pressure deviate from FOPH measurements at a high energy setting (p < 0.01).…”

Section: A Pressure Waveforms At Geometric Focus Of the Shock Sourcementioning

confidence: 88%

“…3,28 The LSHD presented in this study is an upgraded model with reduced low frequency (LF) cutoff from models previously reported. 14,28,31 The spatial resolutions of the LSHD and FOPH are identical. LSHD sensitivity (H LSHD ) is boosted electronically through the use of dc-compensating transimpedance amplification (Z T, ac /Z T, dc ) of the return optical signal, as shown in Eq.…”

Section: A Shock Wave Source and Hydrophonesmentioning

confidence: 99%

“…24,26,[34][35][36] High-speed imaging in Fig. 5(a) suggests that cavitating bubbles formed in a thin layer beneath the light spot may likewise alter the measured 14,31 Filter applied to individual photovoltage measurements prior to pressure calibration and averaging. pressure waveform.…”

Section: A Pressure Waveforms At Geometric Focus Of the Shock Sourcementioning

confidence: 99%

“…3,28 In this study, we compare the performance of the FOPH and LSHD in lithotripter field characterization for both low and clinically applicable source energy settings, to be distinguished from previous fiber optic-style hydrophone and LSHD comparisons at a single spatial position and source energy. 14,31 Interpretation is offered for differences in lithotripter shock wave (LSW) parameters measured with each hydrophone and the roles of cavitation in measurement interference. Advantages and disadvantages related to each hydrophone's usage are discussed with considerations for general applicability in SWL.…”

Section: Introductionmentioning

confidence: 99%

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A comparison of light spot hydrophone and fiber optic probe hydrophone for lithotripter field characterization

Smith

Sankin

Simmons

et al. 2012

Review of Scientific Instruments

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The performance of a newly developed light spot hydrophone (LSHD) in lithotripter field characterization was compared to that of the fiber optic probe hydrophone (FOPH). Pressure waveforms produced by a stable electromagnetic shock wave source were measured by the LSHD and FOPH under identical experimental conditions. In the low energy regime, focus and field acoustic parameters matched well between the two hydrophones. At clinically relevant high energy settings for shock wave lithotripsy, the measured leading compressive pressure waveforms matched closely with each other. However, the LSHD recorded slightly larger |P_| (p< 0.05) and secondary peak compressive pressures (p < 0.01) than the FOPH, leading to about 20% increase in total acoustic pulse energy calculated in a 6 mm radius around the focus (p = 0.06). Tensile pulse durations deviated ~5% (p < 0.01) due to tensile wave shortening from cavitation activity using the LSHD. Intermittent compression spikes and laser light reflection artifacts have been correlated to bubble activity based on simultaneous high-speed imaging analysis. Altogether, both hydrophones are adequate for lithotripter field characterization as specified by the international standard IEC 61846.

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Section: Bubble At Laser Spotsupporting

confidence: 55%

Section: A Pressure Waveforms At Geometric Focus Of the Shock Sourcementioning

confidence: 88%

Section: A Shock Wave Source and Hydrophonesmentioning

confidence: 99%

Section: A Pressure Waveforms At Geometric Focus Of the Shock Sourcementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A comparison of light spot hydrophone and fiber optic probe hydrophone for lithotripter field characterization

Smith

Sankin

Simmons

et al. 2012

Review of Scientific Instruments

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A Fabry–Pérot fiber-optic ultrasonic hydrophone for the simultaneous measurement of temperature and acoustic pressure

Morris

Hurrell

Shaw

et al. 2009

The Journal of the Acoustical Society of America

258

164

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A dual sensing fiber-optic hydrophone that can make simultaneous measurements of acoustic pressure and temperature at the same location has been developed for characterizing ultrasound fields and ultrasound-induced heating. The transduction mechanism is based on the detection of acoustically- and thermally-induced thickness changes in a polymer film Fabry-Perot interferometer deposited at the tip of a single mode optical fiber. The sensor provides a peak noise-equivalent pressure of 15 kPa (at 5 MHz, over a 20 MHz measurement bandwidth), an acoustic bandwidth of 50 MHz, and an optically defined element size of 10 microm. As well as measuring acoustic pressure, temperature changes up to 70 degrees C can be measured, with a resolution of 0.34 degrees C. To evaluate the thermal measurement capability of the sensor, measurements were made at the focus of a high-intensity focused ultrasound (HIFU) field in a tissue mimicking phantom. These showed that the sensor is not susceptible to viscous heating, is able to withstand high intensity fields, and can simultaneously acquire acoustic waveforms while monitoring induced temperature rises. These attributes, along with flexibility, small physical size (OD approximately 150 microm), immunity to Electro-Magnetic Interference (EMI), and low sensor cost, suggest that this type of hydrophone may provide a practical alternative to piezoelectric based hydrophones.

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Characterization of the shock pulse-induced cavitation bubble activities recorded by an optical fiber hydrophone

Kang

Cho²,

Coleman

et al. 2014

The Journal of the Acoustical Society of America

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A shock pressure pulse used in an extracorporeal shock wave treatment has a large negative pressure (<-5 MPa) which can produce cavitation. Cavitation cannot be measured easily, but may have known therapeutic effects. This study considers the signal recorded for several hundred microseconds using an optical hydrophone submerged in water at the focus of shock pressure field. The signal is characterized by shock pulse followed by a long tail after several microseconds; this signal is regarded as a cavitation-related signal (CRS). An experimental investigation of the CRS was conducted in the shock pressure field produced in water using an optical hydrophone (FOPH2000, RP Acoustics, Germany). The CRS was found to contain characteristic information about the shock pulse-induced cavitation. The first and second collapse times (t1 and t2) were identified in the CRS. The collapse time delay (tc = t2 - t1) increased with the driving shock pressures. The signal amplitude integrated for time from t1 to t2 was highly correlated with tc (adjusted R(2) = 0.990). This finding suggests that a single optical hydrophone can be used to measure shock pulse and to characterize shock pulse-induced cavitation.

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Comparison of Light Spot Hydrophone (LSHD) and Fiber Optic Probe Hydrophone (FOPH) for Lithotripter Field Characterization

Cited by 3 publications

References 2 publications

A comparison of light spot hydrophone and fiber optic probe hydrophone for lithotripter field characterization

A comparison of light spot hydrophone and fiber optic probe hydrophone for lithotripter field characterization

A Fabry–Pérot fiber-optic ultrasonic hydrophone for the simultaneous measurement of temperature and acoustic pressure

Characterization of the shock pulse-induced cavitation bubble activities recorded by an optical fiber hydrophone

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