A model to predict dispersion in cancellous bone

In contrast to most biologic tissues, phase velocity in cancellous bone tends to decrease with frequency. A stratified model, consisting of alternating layers of bone and marrow (in vivo) or water (in vitro), has been employed to study this phenomenon. Phase velocity was measured from 300-700 kHz in phantoms consisting of regularly-spaced parallel polystyrene sheets in water, and 30 calcanea in vitro. For the phantoms, the agreement between theory and experiment was good. For the calcanea, the model performs well for predicting the frequency dependence of phase velocity.