Ultrasonic attenuation in human calcaneus from 0.2 to 1.7 MHz

Ultrasonic attenuation has been demonstrated to be a useful measurement in the diagnosis of osteoporosis. Most studies have employed ultrasound in a r ange of frequencies from about 200 kHz-300 kHz to 600 kHz-1 MHz, and many h ave assumed a linear dependence of attenuation on frequency. In order to in vestigate the attenuation properties of human calcaneus at higher frequenci es, 16 defatted human calcanea were interrogated in vitro using two matched pairs of transducers with center frequencies of 500 kHz and 2.25 MHz. The linear dependence of attenuation on frequency seems to extend up to at leas t 1.7 MHz. The correlation between attenuation coefficient and frequency fr om 200 kHz to 1.7 MHz was r = 0.999 (95% confidence interval, CI, = 0.998 - 1.00), The measurements: suggest that some deviations from linear frequenc y dependence of attenuation may occur at lower frequencies (below 400 kHz), however.