A PHANTOM FOR QUANTITATIVE ULTRASOUND OF TRABECULAR BONE

The propagation mechanisms of ultrasound in trabecular bone are poorly understood and have been the subject of extended debate; also, the re producibility of ultrasonic measurements on bone in vivo using commerc ial ultrasound heel-scanning devices is such that the interpretation o f the obtained data is difficult. In this paper we describe recent dev elopments in the production of a bone-mimicking material which is well suited to the task of routine monitoring of commercial ultrasound bon e scanners. The material, based on a standard epoxy resin is fabricate d to a pre-determined porosity value by the inclusion of a marrow-mimi cking material thereby introducing a known and controlled mean pore si ze. Measurements of the velocity and attenuation of the material have been performed over a range of porosity values from 10% to 80% in the frequency range 500-900 kHz; also, broadband ultrasonic attenuation (B UA) values have been obtained from commercial equipment. The material displays velocities in the range 1844-3118 m s(-1) and attenuation ran ging from 7.0 to 17.7 dB cm(-1) at 500 kHz.