Investigation of bovine bone by resonant ultrasound spectroscopy and transmission ultrasound.

The method of resonant ultrasonic spectroscopy (RUS) was evaluated for bovine bone and compared with the traditional wave transmission ultrasound method. In RUS, the resonance structure of a cubic or rectangular specimen is scanned. For some low-damping materials, a single measurement yields sufficient resonant frequencies to determine all of the anisotropic elastic constants. Bone has a high viscoelastic damping at ultrasonic frequency. Consequently, resonance peaks of a cubic specimen tend to overlap. Therefore, the usual RUS method must be modified for application to bone; even so, one cannot obtain all the elastic constants. Concurrent studies with transmission ultrasound were conducted. Results were used to generate a map of the elastic moduli vs position along the bone axis. Stiffness was greatest in the mid part of the bovine femur.