Change of piezoelectric signal in cancellous bone with ultrasound irradiation angle

The effect of the trabecular orientation on the piezoelectric signal in bovine cancellous bone generated by ultrasound irradiation was investigated with "PE-cells", which could correspond to ultrasound receivers using the bone specimens as piezoelectric elements. The PE-cells using the water- and air-saturated specimens with layered trabecular elements were prepared, and the piezoelectric signals were observed when an ultrasound wave at 2 MHz was irradiated at two oblique angles parallel and perpendicular to the trabecular orientation to each PE-cell. All directivities of the PE-cells were significantly different from the directivity of an ordinary ultrasound receiver. It was observed for the water-saturated specimen that the side lobe at the angle parallel to the trabecular orientation became larger than the lobe at the perpendicular angle. On the other hand, it was observed for the air-saturated specimen that the difference between the side lobes at the parallel and perpendicular angles was not significant. (C) 2020 The Japan Society of Applied Physics