de Jong N, Hoff L
Thoraxcentre, Erasmus University Rotterdam, The Netherlands.
Ultrasonics. 1993;31(3):175-81. doi: 10.1016/0041-624x(93)90004-j.
Albunex is an ultrasound contrast agent used in echocardiography and in other areas, it consists of microspheres of which more than 95% have a diameter in the range 1-10 microns. The scattering properties of this agent as functions of ultrasound frequency and microsphere diameter and concentration are investigated. A model of the Albunex microspheres has been previously described, considering the individual microspheres as air bubbles surrounded by a thin elastic shell. In the present study this model is extended by including into it the internal friction in the shell when the microsphere vibrates. Acoustic scattering and transmission are measured in the frequency range from 700 kHz to 12.5 MHz. The measured transmitted power is used to estimate the two parameters in the theoretical model: the shell elasticity parameter, Sp and the shell friction, Sf. Introduction of the shell friction into the model improves the agreement between theory and measurements. For the scattered power, differences between measured and calculated values lie within 3 dB. It is concluded that for the frequencies 2.5 and 5 MHz, microspheres with a diameter between 5 and 12 microns are preferred as these deliver the most significant contribution to the total scattered power and cause relatively little attenuation.
阿尔布奈克斯是一种用于超声心动图及其他领域的超声造影剂，它由微球组成，其中超过95%的微球直径在1至10微米范围内。研究了该造影剂的散射特性与超声频率、微球直径及浓度之间的关系。之前已描述过阿尔布奈克斯微球的模型，即将单个微球视为由薄弹性壳包围的气泡。在本研究中，该模型通过纳入微球振动时壳内的内摩擦而得到扩展。在700千赫至12.5兆赫的频率范围内测量了声散射和透射。测量得到的透射功率用于估计理论模型中的两个参数：壳弹性参数Sp和壳摩擦Sf。将壳摩擦引入模型提高了理论与测量之间的一致性。对于散射功率，测量值与计算值之间的差异在3分贝以内。得出结论，对于2.5兆赫和5兆赫的频率，直径在5至12微米之间的微球是首选，因为这些微球对总散射功率的贡献最大且衰减相对较小。
