本研究在成功大學體外震波碎石機實驗室中分別完成了，在不同放電介質特性下的體外震波碎石機之模擬結石分解實驗與模擬組織的傷害實驗。研究結果顯示真空除氣水比清水作為放電介質，可產生比較大之聚焦點上最大壓力以及比較大之放電時之接地電流量，也因而具有較佳的結石分解特性，此結果可分別由發泡煉石與肺石等二種模擬結石之分解過程圖片中予以驗證，然而伴隨巨大聚焦壓力後的強大張力波即是造成空蝕誘導組織傷害的元兇，本實驗觀察中發現清水造成密集式的傷害，真空除氣水則造成比較分散式的傷害，在減少組織傷害並維持結石分解能力的目標下，於實驗中發現，於真空除氣水與清水中分別加入適量的清潔劑時，於放電後的聚焦點上前者可產生比較高的最大聚焦壓力與最少的負壓值，此結果顯示，真空除氣水與清潔劑的組合作為放電介質可能達到分解結石且減少組織傷害的目的。

An investigation on stone disintegration and tissue damage by an Extracorporal Shock Wave Lithotriptor (ESWL) under different characteristics of current-discharging medium has been conducted in the ESWL Laboratory in National Cheng Kung University. The experimental results indicate that for degassed water the maximum pressure measured at the focal point are much higher than that for tap water. This is due to high grounding current in degassed water. Such a higher pressure on the focal point has a direct contribution to stone disintegration. The sample stones used are leca stones and pneumolith stones. However, to relieve tissue damage caused by cavitation generated by a negative pressure following the positive pulse of a shock, it is necessary to reduce the negative pressure, but retaining a high enough positive pressure. It has been observed that with adding a proper amount of liquid detergent in degassed water, the ratio of the maximum positive pressure to the maximum negative pressure is higher than that without detergent. It is concluded that the degassed water with detergent is a good candidate as a current-discharging medium for an ESWL, since the suggested medium can produce good characteristics of stone disintegration and of reducing tissue damage.

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