Quantitative measurement of tissue elasticity and viscosity has important medical applications because pathologies are often linked to abnormal tissue mechanical properties. Shearwave Dispersion Ultrasound Vibrometry (SDUV) is proposed to quantify tissue viscoelasticity. SDUV uses a focused ultrasound beam within FDA safety limits to stimulate formation and propagation of harmonic shear waves in the studied tissue. The propagation speed of induced shear wave is frequency-dependent (dispersive) and relates to the tissue's mechanical properties. Shear wave speeds at a number of frequencies are measured by pulse-echo ultrasound setup and fit with a theoretical dispersion model to inversely solve for tissue elasticity and...