Our research focuses on developing non-invasive therapeutic ultrasound procedures for non-invasive surgeries and drug delivery. In particular, we are interested in the mechanical bioeffects through ultrasound induced acoustic cavitation. Acoustic cavitation is a phenomenon where rapid cycling from compression to rarefaction results in formation of microbubbles within the tissue. These bubbles have been observed to oscillate and violently collapse releasing tremendous energy. The net effect of cavitation is localized stresses and pressures that can mechanically fragment and subdivide the tissue resulting in cellular destruction.
Our recent studies have shown that mechanical tissue fractionation can be achieved using a number of short, high intensity ultrasound pulses. At a tissue-fluid interface, histotripsy results in localized tissue removal with sharp boundaries, which we use to removal cardiac tissue in treatment of congenital heart disease. In bulk tissue, histotripsy produces mechanical fragmentation of tissue resulting in a liquefied cored with very sharply demarcated boundaries. Histology demonstrates treated tissue within the lesion is fragmented to subcelluar level surrounded by an almost imperceptibly narrow margin of cellular injury. We have been using the bulk tissue fractionation to develop treatment for prostate cancer and breast cancer. Histotripsy has potential has vast medical applications where non-invasive precise tissue ablation, removal or remodeling is needed.