Noninvasive evaluation of bone stiffness by combining microdefocusing method and reflectance method

Acoustic and elastic properties of bone obtained by ultrasonic-based methods are highly useful in the direct evaluation of bone characteristics. Thus, many methods and systems, which are based on the measurement of velocity and/or attenuation of bone, have been developed. On the other hand, bone stiffness has been considered as an effective index for diagnosis of bone disease such as osteoporosis. In the paper, therefore, we propose a new method and system based on the stiffness measurement of bone. In the proposed method, stiffness is determined from the velocity of the leaky surface skimming compressional waves (LSSCWs) obtained by the microdefocusing method and the acoustic impedance obtained by the reflectance method. Each stiffness of a Bakelite and a PMMA samples is accurately determined in a preliminary experiments, and the principle of the method and system performance are confirmed.