球面压电陶瓷型ESWL的冲击波聚焦点对球心的偏移

Deviation of the Factual Focus of Spherical Piezoelectric ESWL from the Spherical Center

为了计算压电陶瓷发射的球面冲击波的焦点,利用Chisnell-Chester-Whitham(CCW)射线方法的一种离散格式,得到了球面冲击波聚焦问题的一些数值解,它们反映了球面压电陶瓷型ESWL几何中心(即球心)附近冲击波聚焦特性。这些数值结果表明,实际的动力学焦点往往不在球心而有所偏移,所以球面压电陶瓷型ESWL的设计和使用中同样应遵从我国行业标准GB/T YY0001-90对于椭球反射面液电式ESWL的实际焦点的规定,即规定压力最大的点为实际焦点。这对压电式ESWL的设计和临床使用具有重要的意义。

To determine the dynamic focus of the piezoelectric ESWL, the deviation of the factual focus of the spherical shock wave from the spherical center was simulated numerically, using Whitham Ray-method. Three dynamic focusing cases were numerically given. It was shown that the dynamic focuses in the factual focusing of spherical piezoelectric ESWL were often different from geometric center. Therefore the definition, the factual focus of ellipsoid electro-hydaulic ESWL in the Standard GB/T YY0001-90 is the point with maximum pressure, should be applied to spherical piezoelectric ESWL. The correct location of the factual focus is very important for design and clinical use of the piezoelectric ESWL.