Change of piezoelectric signal in cancellous bone with ultrasound attenuation

Abstract

Bone fracture healing can be accelerated by ultrasound irradiation. The bone formation can be accompanied by the piezoelectric effect in the bone. To establish the healing method for a joint bone, which is mostly occupied by cancellous bone, the piezoelectric properties in cancellous bone are required to sufficiently understand. Because of large ultrasound attenuation in cancellous bone, the ultrasound wave may be weakly transmitted to the deep part, and the piezoelectric signal may be weakly generated. In this study, the change of the piezoelectric signal in cancellous bone due to the ultrasound attenuation was investigated by numerical simulation. A cubic cancellous bone model was reconstructed from the X-ray microcomputed tomographic image of bovine bone. The cancellous bone models with different thicknesses were created by reducing the size in each direction parallel and perpendicular to the main trabecular orientation. Using a piezoelectric finite-difference time-domain (PE-FDTD) method, the piezoelectric signals generated in cancellous bone by ultrasound irradiation in the thickness direction were simulated, together with the ultrasound signal waveforms propagated through the bone. The variations of the piezoelectric and ultrasound signal amplitudes with the thickness showed that the piezoelectric signal could be scarcely detected at the deep part in cancellous bone.