Numerical investigation of acoustic droplet vaporization and tissue deformation.

Acoustically-triggered droplet vaporization (ADV) and tissue deformation are numerically analyzed by extending a numerical model for ADV process based on a level-set method, which considers multiple interfaces between bubble, droplet and ambient water regions, bubble compressibility and droplet-bubble phase change, to include nearby tissue deformation using a full Eulerian formulation. The tissue is assumed to be a viscoelastic neo-Hookean material to properly handle large deformation. The numerical results show that droplet vaporization causes greater tissue deformation than isothermal bubble growth under the same acoustic and initial size conditions. The computations of ADV near a deformable solid demonstrate various bubble-tissue interactions such as mushroom-shaped bubble formation near an elastic tissue, tissue compression due to high-speed liquid jet, and large tissue deformation and perforation caused by the non-spherical bubble re-expansion and bubble entrapment. The effects of droplet-tissue distance and elastic shear modulus on the tissue deformation and perforation are investigated. [ABSTRACT FROM AUTHOR]