High-resolution finite volume methods for extracorporeal shock wave therapy.

摘要

Extracorporeal Shock Wave Therapy (ESWT) is a noninvasive treatment for bone fractures that fail to heal, necrotic wounds and strained tendons. It is similar to lithotripsy, a nonsurgical treatment for kidney stones. In this treatment a shock wave is generated in water and then focused using an acoustic lens or reflector so the energy of the wave is concentrated in a small region. This technique has been used since the 1980's, but the underlying biological mechanisms are not well understood. In this thesis we have computationally investigated shock wave propagation in ESWT by solving a Lagrangian form of the isentropic Euler equations in the fluid and linear elasticity in the bone using high-resolution finite volume methods. We have also incorporated tissue-like materials into the model through variation of the parameters in the Tait equation of state.;This work differs from prior modeling of ESWT in that we are solving a full three-dimensional system of equations so we can handle complex bone geometries, and our formulation of the equations enables us to consider shear stresses generated within the bone. In this thesis I provide background information on shock wave therapy and prior modeling efforts. I have given details on the set of equations we use to model the wave propagation, as well as results validating this approach.