Determination of Acoustic Cavitation Probabilities and Thresholds Using a Single Focusing Transducer to Induce and Detect Acoustic Cavitation Events: II. Systematic Investigation in an Agar Material

Abstract In the accompanying article (Part I), a method is described to determine acoustic cavitation probabilities in tissue-mimicking materials (TMMs) using a high-intensity focused ultrasound(HIFU) transducer for both inducing and detecting the acoustic cavitation events, and its suitability for different sonicationmodes like continuous wave, single pulses (with pulse lengths from microsecondsto milliseconds) and repeated burst signals is discussed. In Part II, the use of the method for a systematic study of the dependence of the acoustic cavitation thresholds in 3% (by weight) agar phantoms on the temporal sonicationparameters is discussed. The values obtained at a frequency of 1.06 MHz, ranging from (0.58 ± 0.12) MPa for a 3-s continuous wavemode sonicationto (5.2 ± 1.0) MPa for single shots with a length of 10 wave cycles, are discussed and interpreted on the basis of literature values and their self-consistency.