Acoustic droplet vaporization and gas embolotherapy

Abstract

We present an overview of our research group’s work in acoustic droplet vaporization and gas embolotherapy, including bubble and droplet dynamics, bioeffects, targeting of droplets, localized drug delivery, and selective occlusion of blood flow to tumors. In these applications, transvascular liquid perfluorocarbon droplets are injected intravenously and, subsequently, vaporized with ultrasound to selectively form vascular micro- and nano-bubbles that are used for therapy. The resulting bubbles are approximately 125 times the volume of the droplets from which they originate. Embolization of tumors with this methodology involves droplets that are sufficiently large to produce bubbles that will lead to occlusion. Drug-loaded droplet may be used without occlusion if they are sufficiently small. We have used a combination of theoretical, computational, and experimental approaches to elucidate the behaviors and mechanisms involved in acoustic droplet vaporization. In a murine model of hepatocellular carcinoma, we have demonstrated that the combination of gas embolization and chemotherapy can result in complete tumor regression.