Acoustic scattering from transient, micron‐sized cavitation bubbles

Abstract

If cavitation occurs in vivo due to the application of medical ultrasound, it is likely to be difficult to observe. Concern rests less with the destruction of biological cells and more with the more subtle subcellular injuries that could result in damage to components responsible for cell reproduction. Cavitation on the scale of single biological cells—microcavitation—can be observed in vitro by scattering high‐frequency ultrasound (30 MHz) off of single transient cavitation bubbles. An active cavitation detection (ACD) has been used to determine the onset conditions (e.g., cavitation thresholds) in vitro for water with various artificial cavitation nuclei. More recently, the same scattering technique has been employed to observe the radius versus time characteristics of transient cavitation bubbles of one or more cycles. Reports on both threshold measurements and attempts to measure quantitative radius versus time histories of individual bubbles will be presented. The results will be presented in the general context of the joint Yale‐National Center for Physical Acoustics collaborative effort to assess the safety of diagnostic ultrasound. [Work supported by the National Institutes of Health through Grant 4R01‐CA39374.]