Fig. 2

Sequence of HIFU exposure and RF data acquisition. A high-intensity short pulse, named as “trigger pulse,” for the generation of cavitation bubbles was immediately followed by a lower intensity longer duration burst, named as “heating burst,” for the bubble-enhanced heating. The intensity of heating burst is at a similar level as conventional HIFU. The sequence was repeated for 10 s. RF data were acquired during each HIFU intermission period of 4.95 ms