A Non-Invasive Technique for Detecting Stress Waves in Bone Using the Piezoelectric Effect

A stress wave propagating in a long bone is accompanied by a traveling electrical charge generated as a result of the piezoelectric character of bone. An electromagnetic device has been developed which can detect the magnetic fields associated with this charge and which is capable of monitoring stress waves in bone in vivo. The field measurement is independent of the mechanical properties of the soft tissue overlying the bone, so that difficulties previously encountered with vibration and wave propagation tests to determine in vivo properties of bone are avoided. Applications to the diagnosis of bone disorders are discussed.