包膜超声造影微泡的计算机辅助设计、制备与实验研究

目的 研究纳米包膜超声造影微泡的结构参数及声学参数对其次谐波特性的影响，并对其进行优化设计，据此制备适用于次谐波成像的超声造影微泡。方法 基于包膜超声造影微泡的理论模型建立计算机辅助优化设计与分析系统，从理论上分析微泡的结构参数与声学参数等对微泡次谐波特性的影响。同时，对微泡进行分级分离得到不同尺寸分布的微泡，并对其体外声学特性进行测试。结果 仿真计算和实验结果表明当微泡的膜材料一定时，通过控制微泡粒径的分布，在一定的声压条件下可得到较强的次谐波响应；通过分级分离除去较小微泡后所得的次谐波响应比未分离前显著增强。结论 利用基于模型的计算机辅助设计系统能够对微泡的次谐波特性进行优化设计，并对微泡的制备进行理论性指导。

Computer Aided Design, Preparation and Experimental Study on Encapsulated Microbubbles

Objective To study the effects of structural parameters on encapsulated microbubbles' subharmonic characterization and to optimize these parameters to prepare microbubbles suitable for subharmonic imaging. Method A theoretical model for the oscillation of encapsulated microbubbles in ultrasound field was employed to develop a computer aided design system which was used to analyze the effects of structure and acoustic parameters on subharmonic responses of the microbubbles. Microbubbles with different size distributions were prepared by size fractioning, and their quantitative acoustic properties were measured in vitro. Result Theoretical simulation and acoustic measurement showed that subharmonic enhancement could be observed with microbubbles in vitro and numerically at the transmitted frequency of 5 MHz by controlling the size distribution. Larger microbubbles showed higher subharmonic enhancement than non-fractioned ones. Conclusion The subharmonic characterization of encapsulated microbubbles can be optimized by means of this computer aided design system. Thus desired microbubbles can be prepared with the aid of this system.