Effect of Focused Ultrasound on Shear Wave Propagation in Nonlinear Media
摘要
Focused ultrasound (FUS) is an exciting and emerging technology that can ablate or fractionate tissues and is used to treat solid tumors alone or in combination with other therapies. FUS waves at the focus can produce shear waves that can be used to understand the stiffness of the tissue or track treatment progression or completion. Herein, using finite element model (FEM)-based simulations, we test multiple ultrasound frequencies at different focal pressures, producing shear waves in a nonlinear medium. We quantified the displacements and shear stress produced by the shear wave propagation. We observed that for the 0.75 MPa FUS transducer surface pressure, the peak shear stress production was substantially different between 250 and 500 kHz. Furthermore, the time to peak for shear stress waves was lower for the 250 kHz and 0.75 MPa conditions than the 1 MPa condition at 250 kHz and the 1 MPa condition at 500 kHz. In summary, we have developed a framework to evaluate the effect of different FUS transducers in producing shear waves in nonlinear media.