Reduction of bubble cavitation by modifying the diffraction wave from a lithotripter aperture.
Reduction of bubble cavitation by modifying the diffraction wave from a lithotripter aperture.
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DOI：
10.1089/end.2011.0671
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发表时间：
2012-08
影响因子：
2.7
通讯作者：
Yufeng Zhou
中科院分区：
文献类型：
--
作者：
Yufeng Zhou
目的设计一种新的方法来抑制碎石机聚焦区的气泡空化，以降低冲击波对肾损伤的倾向。材料与方法设计并制造了一种边缘扩展器，安装在电液碎石机椭球反射镜的外侧，以干扰孔径处衍射波的产生，但对反射镜内部的声场影响很小。结果在20 kV时，使用边缘延长器的碎石机焦点处的峰值负压（-11.1 ± 0.9vs-10.6 ± 0.7MPa）与原始配置相似，但拉伸波持续时间明显缩短（3.2 ± 0.54vs5.83 ± 0.56 μs，P<0.01）。然而，这两种配置之间的压缩冲击波的振幅和持续时间以及焦平面中的-6 dB波束宽度没有差异。采用被动空化检测法测量了气泡溃灭时间，证实了气泡空化的显著抑制效果。在碎石机焦点处，虽然使用原始HM-3反射器在20 kV下仅需要约30次电击来破裂血管体模，但使用边缘扩展器在300次电击后不会产生任何损伤。同时，20 kV的HM-3型碎石机在200次冲击后，对巴黎石膏模型的碎石效率为50.4 ± 2.0%，与使用边缘扩展器的碎石效率（46.8 ± 4.1%，P=0.005）相当。结论通过改变碎石机孔径处的衍射波可以抑制冲击波引起的气泡空化，显著降低对血管体模的损伤，但碎石能力良好。
PURPOSE A new method was devised to suppress the bubble cavitation in the lithotripter focal zone to reduce the propensity of shockwave-induced renal injury. MATERIALS AND METHODS An edge extender was designed and fabricated to fit on the outside of the ellipsoidal reflector of an electrohydraulic lithotripter to disturb the generation of diffraction wave at the aperture, but with little effect on the acoustic field inside the reflector. RESULTS Although the peak negative pressures at the lithotripter focus using the edge extender at 20 kV were similar to that of the original configuration (-11.1 ± 0.9 vs -10.6 ± 0.7 MPa), the duration of the tensile wave was shortened significantly (3.2 ± 0.54 vs 5.83 ± 0.56 μs, P<0.01). There is no difference, however, in both the amplitude and duration of the compressive shockwaves between these two configurations as well as the -6 dB beam width in the focal plane. The significant suppression effect of bubble cavitation was confirmed by the measured bubble collapse time using passive cavitation detection. At the lithotripter focus, while only about 30 shocks were needed to rupture a blood vessel phantom using the original HM-3 reflector at 20 kV, no damage could be produced after 300 shocks using the edge extender. Meanwhile, the original HM-3 lithotripter at 20 kV can achieve a stone comminution efficiency of 50.4 ± 2.0% on plaster-of-Paris stone phantom after 200 shocks, which is comparable to that of using the edge extender (46.8 ± 4.1%, P=0.005). CONCLUSIONS Modifying the diffraction wave at the lithotripter aperture can suppress the shockwave-induced bubble cavitation with significant reduced damage potential on the vessel phantom but satisfactory stone comminution ability.