Fig. 7.

Distribution of sizes of spherical bubbles produced by a specific HIFU transducer (F-number = 1.52, frequency 1 MHz) at different peak rarefactional focal pressures. For proliferating behaviors, the bubble size immediately preceding the shape transition from spherical was recorded. (a) Representative bubble size distribution observed during a single pHIFU exposure at p⁻ = 7 MPa. Dashed black lines correspond to median bubble size. (b) Dependence of median bubble size on peak rarefactional focal pressure for all bubble behaviors. Bubbles that will proliferate within the pulse are, in average, larger than bubbles that will remain stationary.