Experimental demonstration of 3D passive cavitation imaging using adaptive beamforming

Interest in passive cavitation imaging has increased in recent years with the development of cavitation-based treatments. Using cross-spectral matrix formalism, adaptive beamformers, such as Capon beamforming, MUSIC, and p-DAS, have been adapted to 2D passive cavitation imaging (PAM) (Polichetti et al., 2020). More recently, we adapted this formalism in 3D to enhance the resolution of PAM using a commercial imaging array. Three beamformers have been extended in both 3D and the Frequency Domain: the DAS beamformer, the Robust Capon Beamformer (RCB) and the MidWay (MW) beamformer. A random sparse array configuration of a multiplexed commercial 2D array is used to reduce the number of channels used for the acquisition and to reconstruct 3D-PAM without degrading the quality of the reconstructed images. Such an approach allows for achieving a versatile well-resolved PAM using conventional research systems. In an experimental situation, the cavitation is initiated by a HIFU transducer at the tip of a needle and monitored with a high-speed camera confirming the presence of cavitation. This initial work allows us to envisage a possible future for 3D cavitation imaging using adaptive algorithms and sparse probes.