Effect of pulse repetition frequency on efficiency of tissue erosion in histotripsy with ultrasonic focus scanning in the direction of propagation

Abstract Histotripsy is a non-invasive treatment method that mechanically destroys soft tissues using cavitation bubbles generated by high-intensity focused ultrasound (HIFU) sonication. Our previous study suggested that scanning the HIFU focus in the opposite direction of propagation could improve the time efficiency of shock scattering histotripsy. In this paper, we extend the method by increasing the number of focus scanning and experimentally investigate the dependence of treatment efficiency of the method on the pulse repetition frequency (PRF) of HIFU sonication. The results showed that the energy efficiency of treatment at high PRF decreased as the number of focal scans increased. This observation may be explained by the greater influence of residual bubbles, suggesting that the optimal number of focus scanning for maximizing treatment efficiency depends on the PRF.