Oates C P
Regional Medical Physics Department, District General Hospital, Sunderland, UK.
Phys Med Biol. 1991 Nov;36(11):1433-42. doi: 10.1088/0031-9155/36/11/003.
If a phantom is to produce Doppler spectral waveforms accurately matching those that would be obtained in vivo, it is necessary to use a fluid that behaves like blood in vivo, both acoustically and rheologically. The use of blood itself is undesirable and an analogue is required. Blood exhibits non-Newtonian behaviour as a result of aggregation of erythrocytes at low shear rates. This behaviour affects flow not only in sub-millimetre diameter vessels, but also in large scale structures. An alternative to blood is described that uses finely powdered nylon suspended in a mixture of glycerol and water. The nylon particles used have dimensions and density close to those of erythrocytes and they aggregate at low shear rates to give non-Newtonian behaviour. Viscosity may be varied over a wide range by the addition of liquid detergent. Consideration is given to the importance of haematocrit in modelling pulsatile and disturbed flows as it affects the haemodynamics of flow and the backscattered power of an ultrasound beam. This adaptable blood analogue is suitable for use in models of both large structures and fine vessels.
如果要使仿体产生与体内所获得的多普勒频谱波形精确匹配的波形，就需要使用一种在声学和流变学上都与体内血液表现相似的流体。使用血液本身是不可取的，需要一种替代品。由于红细胞在低剪切速率下会聚集，血液表现出非牛顿流体行为。这种行为不仅会影响亚毫米直径血管中的血流，也会影响大规模结构中的血流。本文描述了一种替代血液的物质，它使用悬浮在甘油和水的混合物中的细粉状尼龙。所使用的尼龙颗粒的尺寸和密度与红细胞相近，并且它们在低剪切速率下聚集，从而呈现出非牛顿流体行为。通过添加液体洗涤剂，粘度可以在很宽的范围内变化。文中考虑了血细胞比容在模拟脉动流和紊乱流中的重要性，因为它会影响血流的血液动力学以及超声束的反向散射功率。这种适应性强的血液替代品适用于大型结构和细小血管的模型。
