title: Shock-induced bubble jetting into a viscous fluid with application to tissue injury in shock-wave lithotripsy.
abstract: Shock waves in liquids are known to cause spherical gas bubbles to rapidly collapse and form strong re-entrant jets in the direction of the propagating shock. The interaction of these jets with an adjacent viscous liquid is investigated using finite-volume simulation methods. This configuration serves as a model for tissue injury during shock-wave lithotripsy, a medical procedure to remove kidney stones. In this case, the viscous fluid provides a crude model for the tissue. It is found that for viscosities comparable to what might be expected in tissue, the jet that forms upon collapse of a small bubble fails to penetrate deeply into the viscous fluid "tissue." A simple model reproduces the penetration distance versus viscosity observed in the simulations and leads to a phenomenological model for the spreading of injury with multiple shocks. For a reasonable selection of a single efficiency parameter, this model is able to reproduce in vivo observations of an apparent 1000-shock threshold before wide-spread tissue injury occurs in targeted kidneys and the approximate extent of this injury after a typical clinical dose of 2000 shock waves.
authors.affiliation: Mechanical Science and Engineering, University of Illinois, IL 61801, USA.jbfreund@illinois.edu
authors.forename: J B
authors.initials: JB
authors.lastname: Freund
authors.forename: R K
authors.initials: RK
authors.lastname: Shukla
authors.forename: A P
authors.initials: AP
authors.lastname: Evan
mesh_terms: D001826:Body Fluids; D005740:Gases; D006801:Humans; D007668:Kidney / Q000293:injuries* / Q000473:pathology; D007669:Kidney Calculi / Q000473:pathology / Q000628:therapy*; D008096:Lithotripsy / Q000009:adverse effects* / Q000379:methods*; D008954:Models, Biological; D014783:Viscosity
chemical_list: D005740:Gases