Acoustic characterization of cavitation intensity: A review

Abstract

Highlights Classification of cavitation as stable or inertial is inadequate in some cases. Cavitation intensity may be underestimated due to inaccurate frequency filtering. Pure cavitation noise should be used to character cavitation intensity.

Barrier-breaking effects of ultrasonic cavitation for drug delivery and biomarker release

“…Note that the cavitation thresholds set for feedback control in those studies were relative or normalized values that varied largely among different ultrasound systems. Wu et al pointed out that the current spectrum-based methods for cavitation threshold calculation is controversial and they recommended a total integration of real cavitation noise over the full spectrum [153] . Therefore, there is an urgent need to develop an international cavitation quantification standard for cross-comparisons of cavitation thresholds and pre-clinical outcomes reported by different research groups.…”

Ultrasound-Targeted Microbubble Destruction: Modulation in the Tumor Microenvironment and Application in Tumor Immunotherapy

“…When ultrasonic pressure reaches a certain threshold, the surrounding liquid is rapidly filled with small cavities of gas and steam, forming microbubbles (MBs), also known as cavitation nuclei. Under the activity of ultrasound, these MBs continue to vibrate, expand and contract, which, when finally burst and collapse (37,38), release instantaneous energy and cause extreme physical phenomena such as luminescence, high temperature, high pressure, discharge, and microjet (39).…”

A high-temperature acoustic field measurement and analysis system for determining cavitation intensity in ultrasonically solidified metallic alloys

“…The continuous spectrum stands for transient cavitation [9] , [16] , [21] , [22] , while the line spectra reflect the dynamic characteristics of stable cavitation [23] , [17] . However, its compositions are complex [24] : in addition to the direct field, cavitation bubbles and linearly pulsating bubbles can also oscillate at a fundamental frequency f 0 and emit a fundamental acoustic signal; nonlinear oscillations of bubbles [25] , as well as large amplitude nonlinear vibration of transducer and waveform distortion in nonlinear acoustic wave propagation, can cause harmonic nf 0 ; the subharmonic 0.5f 0 and ultraharmonic (n + 0.5)f 0 peaks attributed to the combined effects of period doubling [26] , subharmonic oscillations [27] , chaotic oscillations and microjet emission [28] .…”