Theoretical considerations for the use of microbubbles as point targets for phase aberration correction

Bubbles can be produced by vaporization of perfluorocarbon droplets of a few μm diameter. These bubbles can reach up to 100 μm in diameter and their backscatter is calculated to be more than 10 dB above that of several organ tissues. At these sizes and for diagnostic frequencies (2–8 MHz), bubbles can be approximated by the nonrigid sphere scattering solution employed here. This presentation concerns the bubble size and its implications on the backscatter amplitude and the phase error introduced in diagnostic ultrasound when assuming that the bubble acts as a point target for phase aberration correction. The phase error is the difference between the phase at each location along the receiving aperture relative to that at the aperture center, compared with the same relative phase for a perfect point target. Evaluations were made of the phase error with respect to a range of transducer f‐numbers (0.5–2.0) for a specific bubble size (30 μm radius) and at certain frequencies (2–8 MHz). For example, at 5 MHz th...