Group versus Phase Velocity of Shear Waves in Soft Tissues

A paper co-authored by Professor Kevin Parker, graduate student Juvenal Ormachea, and Dr. Zaegyoo Hah of Samsung Medison Co. Ltd. titled "Group versus phase velocity of shear waves in soft tissues" has been e-published by Ultrasonic Imaging, and can be found here. The article describes the distinction between group and phase velocities, and the importance of that distinction to the field of elastography.  For the class of tissues and materials exhibiting power law dispersion, group velocity is significantly greater than phase velocity, and simple expressions are shown to interrelate the commonly measured parameters.  Examples are given from phantoms and tissues.