Advanced Beamforming Techniques for Passive Imaging of Stable and Inertial Cavitation

Passive Acoustic Mapping (PAM) allows real-time imaging of the cavitation activity for ultrasound therapy. However, a reproducible treatment requires accurate monitoring of the two types of cavitation: stable cavitation (oscillating bubbles producing tissue heating or soft mechanical effects) and inertial cavitation (collapsing bubbles producing destructive mechanical damages). To improve their localization, we have adapted a nonlinear beamformer based on the p-th root compression of signals (pDAS) to PAM, since the pDAS enhances resolution and contrast of B-mode images. The proposed method is compared in simulation to PAM and PAM with Phase Coherence Factor (PCF). The results illustrate the superiority of both adaptive beamformers (PCF and pDAS) compared to PAM in terms of resolution and contrast. Moreover the amplitude-based beamformer pDAS compared to PCF achieves a better contrast when imaging inertial cavitation from broadband received signals.