Numerical investigation of ultrasound reflection properties in cancellous bone

Abstract

Bone is composed of two components: cancellous and cortical bone. Cancellous bone is usually surrounded by cortical bone, and therefore, ultrasound waves propagating in bone may reflect at the boundary between the two. In this study, a microcomputed tomographic ({lower case mu}CT) model of cancellous bone was used and ultrasound reflection properties were numerically simulated using a finite-difference time-domain (FDTD) method. To investigate the basic reflection properties, the reflected waveform at normal incidence was calculated using a model having a layer each of cancellous and cortical bone. The reflection properties were analyzed by comparing with the waveform calculated using the cancellous bone model with an absorbing condition at the boundary. When the boundary surface was perpendicular to the main orientation of the trabecular network, reflections of both the fast and slow longitudinal waves were clearly observed in the cancellous bone.