(b) distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion in the liver.  Furthermore, ex vivo liver experiments were performed with a passive cavitation detection system to obtain acoustic emissions.  Examining the frequency spectra produced by the thermal ablation and the boiling histotripsy exposures, it was observed that higher order multiple harmonics as well as higher levels of broadband emissions occurred during the boiling histotripsy insonation.  (a) the different types of acoustic cavitation activity for either a thermal ablation or a mechanical fractionation process and 
THERM