Evaluation of advanced Passive Acoustic Mapping (PAM) beamformers for high-duty-cycle HIFU ablated in Ex Vivo Tissue

High-duty cycle high-intensity focused ultrasound (HIFU) exposures have demonstrated their feasibility for clinical ultrasound thermal therapy. Passive acoustic mapping (PAM) as its unique receiving characteristic that was paralleled with HIFU therapeutic process to monitor the possible cavitation activities. In this research, the quasi continuous-wave (qCW) HIFU exposures (95 % duty cycle, 5 s duration) was set to approach the clinical parameter. Inspired by the DC components could be averaged into significant for long exposure sonification in relative time delay beamformer time exposure acoustics (TEA) (i.e., seismic study). The DC mitigation was incorporated with robust capon beamformer (RCB) (i.e., due to the utilization of uncalibrated imaging array) (RCB-DC) for the residue cavitation energy spread rejection in PAM. Whilst the TEA, CB, RCB, the Multiple signal classification RCB (Music-RCB), and the post-Wiener filtered Music-RCB (WMusic-RCB) were analyzed with RCB-DC in both tissue-mimicking BSA phantoms and ex vivo bovine liver tissue via aforementioned qCW exposure. Final results illustrated that 86 % to (numerical range) 94 % noise area suppression by RCB-DC stood out all other methods while maintaining the same magnitude of computation complexity as RCB that was lower than Music-RCB and WMusic-RCB. Real-time issues of the proposed method and its integration into an in-house developed ultrasound system as the next step will be implemented for the solid clinical ultrasound HIFU monitoring.