Wear Keith A
US Food and Drug Administration, Center for Devices and Radiological Health, HFZ-142, Rockville, Maryland 20852, USA.
J Acoust Soc Am. 2009 Feb;125(2):1197-201. doi: 10.1121/1.3050310.
Frequency-dependent phase velocity was measured in eight cancellous-bone-mimicking phantoms consisting of suspensions of randomly oriented nylon filaments (simulating trabeculae) in a soft-tissue-mimicking medium (simulating marrow). Trabecular thicknesses ranged from 152 to 356 mum. Volume fractions of nylon filament material ranged from 0% to 10%. Phase velocity varied approximately linearly with frequency over the range from 300 to 700 kHz. The increase in phase velocity (compared with phase velocity in a phantom containing no filaments) at 500 kHz was approximately proportional to volume fraction occupied by nylon filaments. The derivative of phase velocity with respect to frequency was negative and exhibited nonlinear, monotonically decreasing dependence on volume fraction. The dependencies of phase velocity and its derivative on volume fraction in these phantoms were similar to those reported in previous studies on (1) human cancellous bone and (2) phantoms consisting of parallel nylon wires immersed in water.
在八个松质骨模拟体模中测量了频率依赖相速度，这些体模由随机取向的尼龙细丝（模拟小梁）悬浮于软组织模拟介质（模拟骨髓）中组成。小梁厚度范围为152至356微米。尼龙细丝材料的体积分数范围为0%至10%。在300至700千赫兹范围内，相速度随频率近似呈线性变化。在500千赫兹时，相速度的增加（与不含细丝的体模中的相速度相比）近似与尼龙细丝所占体积分数成正比。相速度相对于频率的导数为负，且对体积分数呈现出非线性、单调递减的依赖性。这些体模中相速度及其导数对体积分数的依赖性与先前关于（1）人松质骨和（2）由浸入水中的平行尼龙丝组成的体模的研究报告中的依赖性相似。
