High-throughput coagulation by heating with laterally enlarged focus, enhanced by mircobubble clouds created by electronically scanned trigger pulses

Microbubbles are known to enhance ultrasonic tissue heating. However, they do not always provide the desired temperature distribution for high-intensity focused ultrasound (HIFU) treatment unless they are localized in the tissue to be treated. Cavitation clouds, locally generated by extremely high intensity short pulses, can enhance the effect of immediately following heating waves. The throughput of HIFU treatment may significantly be improved thereby. The treatment throughput may be improved even further when generation of multiple cavitation clouds by fast electronic scanning is combined with heating waves with an enlarged focus. The bio-heat transfer simulation showed that heating with an enlarged focus showed higher treatment efficiency than a single spot focus even without trigger pulses generating cavitation clouds, but higher acoustic power is needed. When the heating with an enlarged focus immediately followed the electronically scanned trigger pulses with multiple foci, it showed higher treatment efficiency even at low acoustic power.