Towards an assessment of bone fracture healing using pulsed mode ultrasound

Healing rate of fractured bone differs from one patient to another which may lead to incorrect consequent medical procedures. Thus, quantitative assessment of bone healing after fracture becomes important. In this paper, we present a mathematical model which describes the interaction of a pulsed mode ultrasound waves with a multilayered biological structure. The model is applied to estimate the bone callus thickness and degree of hardness. Different frequencies are utilized to obtain highest measurement sensitivity and accuracy of callus thickness and degree of hardness. It is found that a transducer operating at 1 MHz has the highest sensitivity to the different phases of callus hardening. On the other hand, a 3 MHz transducer yields the highest sensitivity to the thickness of the callus layer. Thus, using both frequencies might prove to be useful for full quantitative assessment of the bone healing process.