Zhou Yufeng, Zhong Pei
Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA.
J Acoust Soc Am. 2003 Jan;113(1):586-97. doi: 10.1121/1.1528174.
Using the Hamilton model [Hamilton, J. Acoust. Soc. Am. 93, 1256-1266 (1993)], the effects of reflector geometry on the pulse profile and sequence of the shock waves produced by the original and upgraded reflector of an HM-3 lithotripter were evaluated qualitatively. Guided by this analysis, we have refined the geometry of the upgraded reflector to enhance its suppressive effect on intraluminal bubble expansion without compromising stone comminution in shock wave lithotripsy. Using the original HM-3 reflector at 20 kV, rupture of a standard vessel phantom made of cellulose hollow fiber (i.d. = 0.2 mm), in which degassed water seeded with ultrasound contrast agents was circulated, was produced at the lithotripter focus after about 30 shocks. In contrast, using the upgraded reflector at 24 kV no rupture of the vessel phantom could be produced within a 20-mm diameter around the lithotripter focus even after 200 shocks. On the other hand, stone comminution was comparable between the two reflector configurations, although slightly larger fragments were produced by the upgraded reflector. After 2000 shocks, stone comminution efficiency produced by the original HM-3 reflector at 20 kV is 97.15 +/- 1.92% (mean +/- SD), compared to 90.35 +/- 1.96% produced by the upgraded reflector at 24 kV (p<0.02). All together, it was found that the upgraded reflector could significantly reduce the propensity for vessel rupture in shock wave lithotripsy while maintaining satisfactory stone comminution.
使用汉密尔顿模型[汉密尔顿，《美国声学学会杂志》93, 1256 - 1266 (1993)]，对HM - 3碎石机原始反射器和升级反射器产生的冲击波的脉冲轮廓和序列上反射器几何形状的影响进行了定性评估。在此分析的指导下，我们对升级反射器的几何形状进行了优化，以增强其对管腔内气泡膨胀的抑制作用，同时不影响冲击波碎石术中结石的粉碎效果。在20 kV电压下使用原始的HM - 3反射器时，由纤维素中空纤维（内径 = 0.2 mm）制成的标准血管模型，其中循环着含有超声造影剂的脱气水，在碎石机焦点处经过约30次冲击后会破裂。相比之下，在24 kV电压下使用升级反射器时，即使经过200次冲击，在碎石机焦点周围20毫米直径范围内的血管模型也不会破裂。另一方面，两种反射器配置下的结石粉碎效果相当，尽管升级反射器产生稍大一些的碎片。在2000次冲击后，20 kV电压下原始HM - 3反射器产生的结石粉碎效率为97.15 +/- 1.92%（平均值 +/- 标准差），而24 kV电压下升级反射器产生的结石粉碎效率为90.35 +/- 1.96%（p<0.02）。总体而言，发现升级反射器在冲击波碎石术中能显著降低血管破裂的倾向，同时保持令人满意的结石粉碎效果。
