CONTRAST AGENT MICROBUBBLE JETTING DURING INITIAL INTERACTION WITH 200-KHZ FOCUSED ULTRASOUND

The initial response of microbubbles flowing through a 500-mu m polycarbonate capillary to a burst of 200-kHz focused ultrasound, at peak-negative pressure amplitudes from 0.7-1.5 MPa, was investigated with dual-perspective high-speed imaging. Directed jetting through the acoustic focus is demonstrated according to the pressure gradients acting across the cavitating microbubbles. At lower amplitudes, repeated microbubble-jetting is accompanied by sudden, intermittent translation. At higher amplitudes a rebound jet also forms, before disintegration into a cavitation cloud. (C) 2019 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology.