Acoustic droplet vaporization for therapeutic and diagnostic applications

A phase shift droplet emulsion is introduced as an aid to unusual ultrasoun d (US) applications. The transpulmonary droplet emulsion (90% < 6 <mu>m dia meter) is made by mixing saline, bovine albumin and dodecafluoropentane. It has been observed that an acoustic pressure threshold exists, above which the droplets vaporize into bubbles approximately 25 times the original diam eter. For frequencies between 1.5 and 8 MHz, the threshold decreases from 4 .5 to 0.75 MPa peak rarefactional pressure, This paper presents preliminary results for droplet preparation and their evaporation as a function of app lied acoustic pressure and frequency, as well as simulations of the lifetim e of these gas bubbles based on gas diffusion. In vivo experiments were sim ulated by the evaporation of droplets in blood flowing under attenuating ma terial. We propose that this agent might be useful for tissue occlusion in cancer treatment, as well as for phase aberration corrections in acoustic i maging. (C) 2000 World Federation for Ultrasound in Medicine & Biology.