Sonic velocity and attenuation in wet compact cow femur for the frequency range 5 to 100 MHz.

Ultrasonic studies on bone have not been done as intensively as other tissues, probably because there is less opportunity to examine bone in vivo by this modality. There is considerable interest in using ultrasonics to learn about the material properties of bone for which purpose the sonic spectrum may be useful. The longitudinal sonic velocity and attenuation have been found for several sections from one sample of wet cow femur for both the axial and radial directions over the frequency range of 5 to 100 MHz. The basic technique was solid-to-solid contact using a fused quartz buffer rod coupled to the bone specimen. There is clear evidence of velocity dispersion which Lakes et al. (1986) did not find over a frequency range up to 16 MHz. While there seems to be a peak in both velocity and attenuation at 70 MHz, it is necessary to obtain measurements at higher frequencies to make sure this is not an artifact. The axial sonic velocity varied from 4.29 km/s at 5 MHz to 4.447 km/s at 50 MHz, while the radial velocity was 3.45 km/s at 5 MHz and increased to 3.62 km/s at 50 MHz. The attenuation coefficient axially started at a mean value of 3.5 db/mm at 5 MHz and increased to a mean of 19 db/mm at 100 MHz. The corresponding radial attenuation coefficients are 5.2 and 26, respectively.