Predicting the acoustic response of a microbubble population for contrast imaging in medical ultrasound

Although the behavior of a bubble in an acoustic field has been studied extensively, few theoretical treatments to date have been applied to simulate the acoustic response of a real population of variably sized microbubbles in a finite-width sound beam. In this paper, we present a modified Trilling equation for single bubble dynamics that has been solved numerically for different conditions. Radiated waveforms from a large number of such bubbles are combined, reflecting their size distribution and location and the shape of a real acoustic beam. The resulting time-domain pressure waveforms can be compared with those obtained experimentally. The dependence of second-harmonic radiation on incident focal amplitude at different frequencies is presented. This model is particularly suited to the study of interaction between a medical ultrasound beam and microbubble contrast agents in aqueous media.