Visualizations of Bubble Motions and Temperature Rises by Focused Ultrasound

Ultrasound propagation in bubbly fluid was numerically analyzed to simulate HIFU (high intensity focused ultrasound) in human body with microbubbles injected into tissues. HIFU is one of promising non-invasive treatments and micorbubbles are expected to enhance heating of body tissues. As ultrasound shows nonlinearity near focal area, high-order perturbation equation of acoustic wave with void fraction (gas volume fraction) was derived and discretized with a finite difference method. Bubble motions and temperature rise due to the bubble oscillations were obtained and visualized with various initial bubble radii and void fractions.