Mass transfer during radial oscillations of gas bubbles in viscoelastic mediums under acoustic excitation

The generation of acoustic cavitation in viscoelastic mediums (e.g. human or animal tissue) is an essential topic for facilitating non-invasive therapeutic ultrasonic treatment of serious diseases (e.g. tumors). In present paper, mass transfer during radial oscillations of gas bubbles in viscoelastic mediums under acoustic excitation is theoretically investigated and influences of several parameters (e.g. shear modulus, saturation condition and viscosity) on the mass diffusion across bubble interfaces are discussed. The characteristics of acoustic cavitation generated in vivo are also explained based on our predictions by re-visiting the pioneering studies in the field. Comparing with previous predictions in the literature, our predictions reveal that values of maximum bubble sizes growing through mass diffusion is larger and required time reaching above maximum bubble size is longer, suggesting that medium viscoelasticity is one of paramount parameters for predicting mass diffusion of cavitation bubbles in tissue.