Modeling of an electrohydraulic lithotripter with the KZK equation
Modeling of an electrohydraulic lithotripter with the KZK equation
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DOI：
10.1121/1.427039
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发表时间：
1999-07-01
影响因子：
2.4
通讯作者：
Cleveland, RO
中科院分区：
文献类型：
--
作者：
Averkiou, MA;Cleveland, RO
用非线性抛物线波方程（KZK方程）对物体外冲击波岩石纤维（KZK方程）进行建模。该模型解释了衍射，非线性和热量吸收。用于求解时间域中的KZK方程的数值算法用于模拟岩石质晶体的椭圆形反射器口的声音传播。反射器中的传播以几何声学为模型。结果表明，椭圆形反射器内的非线性失真可以在某些参数中起重要作用。将计算出的波形与在临床岩石纤维中测得的波形进行比较，并发现良好的一致性。结果表明，最大负压的空间位置是前焦点发生的，这表明最强的空化活动也将位于焦点前。考虑到具有压力释放反射器的岩性磨牙的冲击波的传播，由于非线性传播，焦距波形并不是刚性反射器的倒数。提出了通过组织传播的结果。波形与水中预测的波形相似，只是组织中较高的吸收降低了峰值幅度并延长了冲击的上升DME。 （c）1999美国声学学会。 [S0001-4966（99）04306-4]。
The acoustic pressure field of an electrohydraulic extracorporeal shock wave lithotripter is modeled with a nonlinear parabolic wave equation (the KZK equation). The model accounts for diffraction, nonlinearity, and thermoviscous absorption. A numerical algorithm for solving the KZK equation in the time domain is used to model sound propagation from the mouth of the ellipsoidal reflector of the lithotripter. Propagation within the reflector is modeled with geometrical acoustics. It is shown that nonlinear distortion within the ellipsoidal reflector can play an important role for certain parameters. Calculated waveforms are compared with waveforms measured in a clinical lithotripter and good agreement is Found. It is shown that the spatial location of the maximum negative pressure occurs pre-focally which suggests that the strongest cavitation activity will also be in front of the focus. Propagation of shock waves from a lithotripter with a pressure release reflector is considered and because of nonlinear propagation the focal waveform is not the inverse of the rigid reflector. Results from propagation through tissue are presented; waveforms are similar to those predicted in water except that the higher absorption in the tissue decreases the peak amplitude and lengthens the rise dme of the shock. (C) 1999 Acoustical Society of America. [S0001-4966(99)04306-4].