Frizzell L A, Carstensen E L, Davis J D
J Acoust Soc Am. 1979 May;65(5):1309-12. doi: 10.1121/1.382749.
Ultrasonic attenuation coefficients were measured in mammalian liver for frequencies ranging from 0.5 to 10 MHz and for a range of sample preparations. Certain preparative procedures were found to greatly increase the low-frequency attenuation coefficient due to the introduction of bubbles into the sample. The low-frequency attenuation was reduced by storage at low temperatures or by pressurization, each caused the bubbles to go into solution, resulting in an attenuation coefficient that was a simple power function of frequency. Absorption coefficients of in vitro and in vivo samples were found to be similar and to show much less dependence on sample preparation than the attenuation measurements. These studies suggest that properties of carefully prepared in vitro samples are indicative of the in vivo properties.
在哺乳动物肝脏中测量了频率范围为0.5至10MHz以及一系列样品制备条件下的超声衰减系数。发现某些制备程序由于向样品中引入气泡而极大地增加了低频衰减系数。通过低温储存或加压可降低低频衰减，这两种方法都会使气泡溶解，从而得到一个与频率呈简单幂函数关系的衰减系数。发现体外和体内样品的吸收系数相似，并且与衰减测量相比，对样品制备的依赖性要小得多。这些研究表明，精心制备的体外样品的特性可指示体内特性。
