Abstract:

Studies of application of acoustic energy for noninvasive skeletal diagnostics have shown feasibility and demonstrated the advantages of utilizing acoustic techniques for bone mass measurements. Unlike conventional radiological techniques, acoustic techniques emit no radiation, are low cost, and utilize equipment which is portable and easy to operate. Although a significant number of acoustic tests have been performed, these techniques have not been used as bone diagnostic tools in clinical applications because of the difficulties in the interpretation of measurements. Thus, ultrasound velocity and attenuation depend on density as well as on certain other properties of bone. The effect of soft tissues creates additional difficulties in the interpretation and use of these techniques. The proposed infrasound method involves measurements of the ``rigid body'' resonance of a tibia or ulna with the use of specially designed arrangement, which greatly simplifies a biomechanical model of tibia (ulna). This makes the measurement and its interpretation much more accurate. Numerical analysis of the developed model showed that the mass of bone and its loss can be accurately measured and these measurements do not depend on variation in bone flexibility and soft tissue parameters. An experimental setup was arranged and in vivo measurements were conducted and proved the basic concept of the proposed method. [Work supported by NASA.]