Campbell J A, Waag R C
J Acoust Soc Am. 1984 Jun;75(6):1879-86. doi: 10.1121/1.390989.
Random media with different structural properties were used to simulate some of the differences in liver morphology that may occur with disease. First, a reference medium consisting of glass spheres in agar was studied to verify the accuracy and precision of the data obtained with our equipment and processing procedures. Then, studies were conducted on a pair of media comprised of graphite particles in gelatin, one of the pair with twice as many particles as the other. Finally, studies were carried out on a set of media composed of Sephadex particles in water. Three samples were employed, each with a different size of Sephadex. The average differential scattering cross section per unit volume sigma sd (v) of each media was obtained as a function of scattering angle v and frequency. The measured sigma sd were compared with predictions based on models of scattering from the media. The agreement between the measured and predicted sigma sd of the glass sphere medium was excellent. The graphite medium with twice the number of particles as the other was observed to scatter twice as much power as the other. The shape of the angular scattering pattern measured from each size of Sephadex followed the prediction reasonably well. The largest size exhibited marked variations in the shape of sigma sd as a function of frequency, while the absolute magnitude of sigma sd of the smallest size grade was extremely sensitive to frequency. Our results suggest that the dependence of sigma sd (v) on scatterer number density and size, both in absolute magnitude and shape, can provide reliable information which may be useful in the diagnosis of some diseases.
使用具有不同结构特性的随机介质来模拟疾病可能导致的肝脏形态差异。首先，研究了一种由琼脂中的玻璃球组成的参考介质，以验证我们的设备和处理程序所获得数据的准确性和精确性。然后，对一对由明胶中的石墨颗粒组成的介质进行了研究，其中一对介质中的颗粒数量是另一对的两倍。最后，对一组由水中的葡聚糖颗粒组成的介质进行了研究。使用了三个样本，每个样本的葡聚糖大小不同。获得了每种介质每单位体积的平均微分散射截面σsd(v)作为散射角v和频率的函数。将测量的σsd与基于介质散射模型的预测结果进行了比较。玻璃球介质测量值与预测值之间的一致性非常好。观察到颗粒数量是另一种介质两倍的石墨介质散射的功率是另一种介质的两倍。从每种大小的葡聚糖测量得到的角散射图案形状与预测结果相当吻合。最大尺寸的样本在σsd形状随频率变化方面表现出明显差异，而最小尺寸等级的σsd绝对值对频率极为敏感。我们的结果表明，σsd(v)对散射体数量密度和尺寸的依赖性，无论是在绝对值还是形状方面，都可以提供可靠的信息，这可能有助于某些疾病的诊断。
