Demonstration of drug delivery by the interaction of ultrasound and drug-loaded nanodroplets/micelles. A nu/nu mouse bearing two ovarian carcinoma tumors immediately before (A) and 3 weeks after the treatment (B). The mouse was treated by four systemic injections of paclitaxel-loaded nanodroplets given twice weekly, while only the right tumor was sonicated by 1 MHz continuous-wave ultrasound 4 hours after the injection. The left tumor grew at the same rate as the controls, while the right tumor regressed, demonstrating paclitaxel release into the tumor volume. Reprinted from J Control Release, Vol. 138, Rapoport NY, Kennedy AM, Shea JE, Scaife CL, Nam KH, “Controlled and targeted tumor chemotherapy by ultrasound-activated nanoemulsions/microbubbles”, 268–76 (2009), with permission from Elsevier.