Jöchle K, Debus J, Lorenz W J, Huber P
Department of Biophysics and Medical Radiation Physics, German Cancer Research Center, Heidelberg, Germany.
Ultrasound Med Biol. 1996;22(3):329-38. doi: 10.1016/0301-5629(96)00031-2.
Transient cavitation seems to be a very important effect regarding the interaction of pulsed high-energy ultrasound with biologic tissues. Using a newly developed laser optical system we are able to determine the life-span of transient cavities (relative error less than +/- 5%) in the focal region of a lithotripter (Lithostar, Siemens). The laser scattering method is based on the detection of scattered laser light reflected during a bubble's life. This method requires no sort of sensor material in the pathway of the sound field. Thus, the method avoids any interference with bubble dynamics during the measurement. The knowledge of the time of bubble decay allows conclusions to be reached on the destructive power of the cavities. By combining the results of life-span measurements with the maximum bubble radius using stroboscopic photographs we found that the measured time of bubble decay and the predicted time using Rayleigh's law only differs by about 13% even in the case of complex bubble fields. It can be shown that the laser scattering method is feasible to assess cavitation events quantitatively. Moreover, it will enable us to compare different medical ultrasound sources that have the capability to generate cavitation.
对于脉冲高能超声与生物组织的相互作用而言，瞬态空化似乎是一种非常重要的效应。利用新开发的激光光学系统，我们能够确定碎石机（西门子公司的Lithostar）焦点区域瞬态空泡的寿命（相对误差小于±5%）。激光散射法基于检测气泡寿命期间反射的散射激光。该方法在声场路径中不需要任何类型的传感材料。因此，该方法避免了测量过程中对气泡动力学的任何干扰。了解气泡衰减时间有助于得出关于空泡破坏力的结论。通过将寿命测量结果与频闪摄影得到的最大气泡半径相结合，我们发现，即使在复杂气泡场的情况下，测量得到的气泡衰减时间与根据瑞利定律预测的时间仅相差约13%。可以证明，激光散射法可用于定量评估空化事件。此外，它将使我们能够比较具有产生空化能力的不同医用超声源。
