Estimation of elasticity and viscosity in heterogeneous medium using FDTD method and AHI algorithm

Mechanical properties of tissues in terms of elasticity and viscosity provide us useful information which may be used in detecting tumors. These parameters can be estimated from the measurement of particle velocities of shear wave propagation which is generated by a vibrating needle at a certain frequency. For the heterogeneous medium, the finite difference time domain (FDTD) is an effective method to present the shear wave propagation. The elasticity and viscosity are then estimated using the algebraic Helmholtz inversion (AHI) algorithm. However, there is a lack of deep investigation of estimation by combining FDTD method and AHI algorithm. Thus, this paper presents a complete system which includes the principle of excitation and measurement, the FDTD to model the shear wave propagation, the AHI algorithm to estimate the elasticity and viscosity, and the investigation on frequency-dependent the elasticity and viscosity. Also, we suggest that the excitation frequency of 200 Hz will offer the best estimation of the elasticity and viscosity.