  Speed of sound and attenuation as a function of frequency between 2 and 18
MHz were measured and compared for a cancerous prostate cell line and a healthy
prostate cell line. Speed of sound for the cancerous cells line was found to be
1521.4 $\pm$ 0.8~m/s, which was equivalent to the speed of sound for the
healthy cell line of 1521.5 $\pm$ 0.6~m/s. The average attenuation coefficient
was 0.091 $\pm$ 0.003 $\frac{\rm{dB}}{\rm{cm-MHz}}$ for the cancerous prostate
cell line and 0.057 $\pm$ 0.003 $\frac{\rm{dB}}{\rm{cm-MHz}}$ for the healthy
prostate cell line, showing a higher attenuation for the cancerous cell line.
