Formulation of acoustically activatable particles having low vaporization energy and methods for using same

A method or producing particles or materials for ultrasound activation, comprising:

• extruding or emulsifying a first substance comprising at least one component that is a perfluorocarbon or perfluorochemical having a boiling point below 25° C. at atmospheric pressure into or in the presence of a second substance to create a bubble in which the first substance is encapsulated by the second substance and wherein at least some of the first substance exists in a gaseous phase at the time of encapsulation of the first substance within the second substance, and, after formation of the bubble, causing the first substance that is In the gaseous phase In the bubble to condense to a liquid phase, which causes the bubble to transform into a droplet or emulsion having a core consisting of a liquid;
• wherein the droplet or emulsion is an activatable phase change agent that remains a droplet having a core consisting or a liquid at 25° C. and atmospheric pressure, and wherein the first substance has a boiling point below 25° C. at atmospheric pressure.