Study on Thrombolysis Using Small Ultrasound Vibration.

结果表明，在超声频率为20 KHz、功率为1 W的条件下，直径为3 mm的超声探头能有效地破碎体外血栓。对自制的几种薄型换能器进行了水浴功率测试。利用微泡扩散的溶液可以观察到水中超声功率的方向和大小。将超声频率调整到最佳效果后，应用该换能器进行体外溶栓试验。超声辐射与尿激酶联合应用的凝块干重比单独使用尿激酶的凝块干重小。这种超声效应在微泡存在下增强，可能是由于空化现象。需要长寿命的微泡，而普通的微泡容易溶于水或血液中。我们研制了一种新的稳定微泡剂，它是由十二碳正戊烷制成的。通过超声心动图检查其在犬中的耐久性。经外周静脉注入十二氟戊烷溶液，观察心肌显影情况。剂量大于0.5ml/kg时，心肌显影时间长，显影时间可达10 ~ 50分钟。结论：超声微换能器与微泡联合应用可增强体内溶栓作用。

It has been revealed that blood clot made in vitro was broken by ultrasound radiation from the ultrasound tip as thin as 3mm in diameter, in which the ultrasound frequency was 20KHz and the power was 1 Watt. Several self-made thin transducer was examined its power in a water bath. Direction and magnitude of the ultrasound power in the water could be visualized using solution diffused by microbubbles. After adjusting the ultrasound frequency to be maximize its effect, the transducer was applied to examine whether the transducer could enhance the thrombolysis in vitro. Dry weight of the clot was less by combination use of ultrasound radiation and Urokinase than that by sole use of Urokinase. This ultrasound effect is enhanced under presence of microbubbles, probably due to cavitation phenomenon. Long-life microbubbles are needed, while ordinal microbubbles are easy to be solved into water or blood. We developed a new agent of stable microbubbles, which was made from dodecafluoropentane. Its durability was examined in canines by echocardiography. The solution of dodecafluoropentane was injected into the peripheral vein and the myocardial opacification was evaluated. Using a dosage over 0.5ml/kg, the myocardium was clearly opacified for long period as over 10 to 50 minutes. Weconclude that the combination use of microtransducer of ultrasound and microbubbles will enhance the thrombolysis in vivo.