Measurements of cavitation dose, echogenicity, and temperature during ultrasound ablation

T. Douglas Mast, Vasant A. Salgaonkar, Chandrapriya Karunakaran, John A. Besse, Saurabh Datta, Christy K. Holland

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Ultrasound ablation experiments were performed, with simultaneous measurements of acoustic emissions, tissue echogenicity, and tissue temperature, on fresh, degassed bovine liver. The tissue was exposed to bursts of unfocused, continuous-wave, 3.10 MHz from a 3 mm-diameter, 32-element array, which performed B-scan imaging with the same piezoelectric elements during quiescent periods. Exposures employed pulse lengths of 0.9-3.3 s with pressure amplitudes of 0.8-1.4 MPa and duty cycles of 97-99% for exposure times of 6-20 min, sufficient to achieve significant thermal coagulation in all cases. RF echo traces from the array, time-domain signals received by a 1 MHz, unfocused passive cavitation detector, and tissue temperature detected by a needle thermocouple were sampled 0.3-1.1 times per second. Tissue echogenicity was quantified, within the region of significant tissue heating, from the amplitude of RF signals received by the array. Cavitation dose was 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 effects 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, tissue echogenicity, tissue temperature, and ablation rate. Tissue echogenicity correlated significantly with subharmonic and low-frequency emissions as well as tissue temperature, but was uncorrelated with broadband emissions. Ablation rate correlated significantly with broadband and low-frequency emissions, but was uncorrelated with subharmonic emissions.

Original languageEnglish (US)
Title of host publication6th International Symposium on Therapeutic Ultrasound
Pages335-341
Number of pages7
DOIs
Publication statusPublished - Sep 24 2007
Externally publishedYes
Event6TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND - Oxford, United Kingdom
Duration: Aug 30 2007Sep 2 2007

Publication series

NameAIP Conference Proceedings
Volume911
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference6TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND
CountryUnited Kingdom
CityOxford
Period8/30/079/2/07

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Keywords

  • Ablation
  • Intense ultrasound
  • Passive cavitation detection
  • Therapy monitoring

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science
  • Physics and Astronomy(all)
  • Nature and Landscape Conservation

Cite this

Mast, T. D., Salgaonkar, V. A., Karunakaran, C., Besse, J. A., Datta, S., & Holland, C. K. (2007). Measurements of cavitation dose, echogenicity, and temperature during ultrasound ablation. In 6th International Symposium on Therapeutic Ultrasound (pp. 335-341). (AIP Conference Proceedings; Vol. 911). https://doi.org/10.1063/1.2744294