Strelitzki R, Truscott J G
Centre for Bone and Body Composition Research, University of Leeds, UK.
Med Eng Phys. 1998 Mar;20(2):132-8. doi: 10.1016/s1350-4533(97)00054-4.
The broadband ultrasonic attenuation (BUA) was measured in 10 os calces on the same site with two transducer separations and five different receiving apertures built from perspex. The results displayed relative differences greater than 40%. However, a clear trend (increasing or decreasing BUA) with smaller aperture size or transducer separation was not observed and hence the differences do not seem to be predictable. The cause for this may be the influence of four factors--averaging, phase cancellation, diffraction and scattering--which are interactive and frequency dependent. This means that values measured with different equipment and experimental set-up are not directly comparable and hence the introduction of measurement standards seems to be necessary.
在10块跟骨的同一部位测量了宽带超声衰减（BUA），使用了两种换能器间距以及由有机玻璃制成的五个不同接收孔径。结果显示相对差异大于40%。然而，未观察到随着孔径尺寸或换能器间距变小而出现的明显趋势（BUA增加或减少），因此这些差异似乎不可预测。其原因可能是平均、相位抵消、衍射和散射这四个因素的影响，它们相互作用且与频率相关。这意味着用不同设备和实验设置测量的值不能直接比较，因此引入测量标准似乎很有必要。
