Tracking the deformation of a tissue phantom induced by ultrasound-driven bubble oscillations

Microbubbles are used as contrast agents in ultrasound medical imaging. Once the microbubbles are injected into the body, they flow through the vascular system, confined by viscoelastic boundaries. The proximity of the boundaries affects the dynamics of the bubbles in ultrasound, in a manner that depends on the boundary's viscoelastic properties. Experiments on violently collapsing bubbles have revealed the dynamics of deformation of blood vessel walls. However, the deformation field induced by a bubble undergoing small-amplitude oscillations, relevant for ultrasound imaging, is difficult to access in experiment, and has not been reported yet. We present an experimental method to measure the deformation field induced by a bubble oscillating inside a microchannel within a tissue phantom. We use high-speed video microscopy to track the displacement of tracer particles embedded in the phantom, along with the dynamics of the bubble.