Measurement of longitudinal wave velocity in trabeculae by micro-Brillouin scattering

Ultrasonic wave velocities in a small trabecula of bovine femur were investigated using micro-Brillouin scattering technique. Our micro-Brillouin scattering system enables the measurement of wave velocities in the GHz range over a minute area (diameter: approximately 10 ¿m). Using thin trabecular samples with thickness of about 150 ¿m, the distribution of longitudinal wave velocity in a trabecula was observed. In the direction parallel to the trabecula, the velocity changed due to the measured point. The average velocities of each trabecula were similar and approximately 4.92×10³ m/s, despite the difference of trabecular shape (aspect ratio). In addition, the difference was not statistically significant between trabeculae which align in bone axis or anterior-posterior directions. The effects of trabecular direction and aspect ratio on the velocity were not statistically significant. These data tell us the possibility that the average elastic properties are similar in all trabeculae.