Dynamics and control of cavitation during high-intensity focused ultrasound application

Thomas, Charles R.; Farny, Caleb H.; Coussios, Constantin C.; Roy, Ronald A.; Holt, R. Glynn

doi:10.1121/1.1901744

Cited by 41 publications

(29 citation statements)

References 11 publications

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“…Since acoustic emissions may originate at any point within the simultaneously sonicated and heated tissue region (volumẽ 6 ml, based on observed ablation rates), this broad sensitivity pattern ensured that all significant emissions were recorded throughout each treatment. The resulting spatial averaging provides better characterization of overall cavitation activity for our bulk ablation experiments, compared to the highly-focused detectors appropriate for HIFU ablation (Rabkin et al 2005(Rabkin et al , 2006Thomas et al 2005;Farny et al 2005;McLaughlan et al 2006;Coussios et al 2006).…”

Section: Measurementsmentioning

confidence: 99%

“…Recent experimental studies have employed passive cavitation detection during highintensity focused ultrasound (HIFU) exposures (Rabkin et al 2005(Rabkin et al , 2006; Thomas et al 2005;Farny et al 2005;McLaughlan et al 2006;Coussios et al 2006). These studies have shown that cavitation causing both subharmonic emissions, consistent with stable bubble shape oscillations, and broadband emissions, consistent with inertial bubble collapse, can occur during HIFU treatments.…”

Section: Introductionmentioning

confidence: 99%

“…These studies have shown that cavitation causing both subharmonic emissions, consistent with stable bubble shape oscillations, and broadband emissions, consistent with inertial bubble collapse, can occur during HIFU treatments. Some correlation has been found between broadband acoustic emission levels and increased B-scan image brightness (Rabkin et al 2005(Rabkin et al , 2006 as well as enhanced heating effects (Thomas et al 2005;Coussios et al 2006). However, it has also been shown that broadband and subharmonic emission levels do not correspond precisely with increases in tissue echogenicity (Rabkin et al 2005;McLaughlan et al 2006), and that broadband emissions can decrease in some cases as the tissue temperature rises (Farny et al 2005;Coussios et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Some correlation has been found between broadband acoustic emission levels and increased B-scan image brightness (Rabkin et al 2005(Rabkin et al , 2006 as well as enhanced heating effects (Thomas et al 2005;Coussios et al 2006). However, it has also been shown that broadband and subharmonic emission levels do not correspond precisely with increases in tissue echogenicity (Rabkin et al 2005;McLaughlan et al 2006), and that broadband emissions can decrease in some cases as the tissue temperature rises (Farny et al 2005;Coussios et al 2006). Kilohertz-frequency emissions, consistent with tissue boiling (Osborne and Holland 1947;Ying 1973), have also been detected during HIFU exposures (McLaughlan et al 2006;Sanghvi et al 1995;Anand et al 2004), and have been found to correlate with enhanced backscattering from tissue (Sanghvi et al 1995;McLaughlan et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Mast

Salgaonkar

Karunakaran

et al. 2008

Ultrasound in Medicine & Biology

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Acoustic emissions associated with cavitation and other bubble activity have previously been observed during ultrasound ablation experiments. Since detectable bubble activity may be related to temperature, tissue state, and sonication characteristics, these acoustic emissions are potentially useful for monitoring and control of ultrasound ablation. To investigate these relationships, ultrasound ablation experiments were performed with simultaneous measurements of acoustic emissions, tissue echogenicity, and tissue temperature, on fresh bovine liver. Ex vivo tissue was exposed to 0.9-3.3 s bursts of unfocused, continuous-wave, 3.10 MHz ultrasound from a miniaturized 32-element array, which performed B-scan imaging with the same piezoelectric elements during brief quiescent periods. Exposures employed pressure amplitudes of 0.8-1.4 MPa for exposure times of 6-20 min, sufficient to achieve significant thermal coagulation in all cases. Acoustic emissions received by a 1 MHz, unfocused passive cavitation detector, beamformed Aline signals acquired by the array, and tissue temperature detected by a needle thermocouple were sampled 0.3-1.1 times per second. Tissue echogenicity was quantified by the backscattered echo energy from a fixed region of interest within the treated zone. Acoustic emission levels were quantified from the spectra of signals measured by the passive cavitation detector, including subharmonic signal components at 1.55 MHz, broadband signal components within the band 0.3-1.1 MHz, and low-frequency components within the band 10-30 kHz. Tissue ablation rates, defined as the thermally ablated volumes per unit time, were assessed by quantitative analysis of digitally imaged, macroscopic tissue sections. Correlation analysis was performed among the averaged and time-dependent acoustic emissions in each band considered, B-mode tissue echogenicity, tissue temperature, and ablation rate. Ablation rate correlated significantly with broadband and low-frequency emissions, but was uncorrelated with subharmonic emissions. Subharmonic emissions were found to depend strongly on temperature in a nonlinear manner, with significant emissions occurring within different temperature ranges for each sonication amplitude. These results suggest potential roles for passive detection of acoustic emissions in guidance and control of bulk ultrasound ablation treatments.

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Section: Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Mast

Salgaonkar

Karunakaran

et al. 2008

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

show abstract

“…Previous investigators have used both active and passive cavitation detection techniques (Everbach 1997;Holland and Apfel 1990;Holland et al 1992;Leighton 1997;Roy et al 1990; Thomas et al 2005). Active cavitation detection is preferable when very high spatial resolution is required and it is desirable to observe individual cavitation events.…”

Section: Passive Cavitation Detection Systemmentioning

confidence: 99%

Correlation of cavitation with ultrasound enhancement of thrombolysis

Datta

Coussios

McAdory

et al. 2006

Ultrasound in Medicine & Biology

255

238

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Pulsed ultrasound, when used as an adjuvant to recombinant tissue plasminogen activator (rt-PA), has been shown to enhance thrombolysis in the laboratory as well as in clinical trials for the treatment of ischemic stroke. The exact mechanism of this enhancement has not yet been elucidated. In this work, stable and inertial cavitation (SC and IC) are investigated as possible mechanisms for this enhancement. A passive cavitation detection scheme was utilized to measure cavitation thresholds at 120 kHz (80% duty cycle, 1667 Hz pulse repetition frequency) for four host fluid and sample combinations: plasma, plasma with rt-PA, plasma with clot and plasma with clot and rt-PA. Following cavitation threshold determination, clots were exposed to pulsed ultrasound for 30 min in vitro using three separate ultrasound treatment regimes: (1) no cavitation (0.15 MPa), (2) SC alone (0.24 MPa) or (3) SC + IC combined (0.36 MPa) in the presence of rt-PA. Percent clot mass loss after each treatment was used to determine thrombolysis efficacy. The highest percent mass loss was observed in the stable cavitation regime (26%), followed by the combined stable and inertial cavitation regime (20.7%). Interestingly, the percent mass loss in clots exposed to ultrasound without cavitation (13.7%) was not statistically significantly different from rt-PA alone (13%) [p > 0.05]. Significant enhancement of thrombolysis correlates with presence of cavitation and stable cavitation appears to play a more important role in the enhancement of thrombolysis.

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Selektive Ultraschall‐Kavitation an strukturierten hydrophoben Oberflächen

et al. 2010

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Beschallte Platten: Sonochemie an Oberflächen kann durch Oberflächenstrukturierung gesteuert werden. Eine Gasblasenkeimbildung findet vorwiegend an hydrophoben Oberflächen statt (linkes Bild); dementsprechend können diese gezielt mit Ultraschall behandelt werden. Das rechte Bild zeigt eine strukturmodifizierte Al‐Platte nach Ultraschallbehandlung. Der innere, kreisrunde Bereich ist hydrophil, der äußere hydrophob.

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Dynamics and control of cavitation during high-intensity focused ultrasound application

Cited by 41 publications

References 11 publications

Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Correlation of cavitation with ultrasound enhancement of thrombolysis

Selektive Ultraschall‐Kavitation an strukturierten hydrophoben Oberflächen

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