Measurement of airborne ultrasonic slow waves in calcaneal cancellous bone

Measurements of an airborne ultrasonic wave were made in defatted cancellou s bone from the human calcaneus using standard ultrasonic equipment. The wa ve propagating under these conditions was consistent with a decoupled Blot slow wave travelling in the air alone, as previously reported in gas-satura ted foams. Reproducible measurements of phase velocity and attenuation coef ficient were possible, and an estimate of the tortuosity of the trabecular framework was derived from the high frequency limit of the phase velocity. Thus the method offers a new approach to the acoustic characterisation of b one in vitro which, in contrast to existing techniques, has the potential t o yield information directly characterising the trabecular structure. (C) 1 999 IPEM. Published by Elsevier Science Ltd. All rights reserved.