Controlled cavitation to augment SWL stone comminution: mechanistic insights in vitro.
Controlled cavitation to augment SWL stone comminution: mechanistic insights in vitro.
复制标题
DOI：
10.1109/tuffc.2013.2566
复制
发表时间：
2013-02
期刊：
影响因子：
--
通讯作者：
Hall TL
中科院分区：
文献类型：
--
作者：
Duryea AP;Roberts WW;Cain CA;Hall TL
冲击波岩石疗法（SWL）的石材委员会已被证明是由于直接赋予石头的机械应力以及穴位微泡的活性。这项研究，我们通过使用组织疗法的超声疗法进一步探讨了SWL石材委员会的重要性。 p-）为8 MPA使用1 Hz的电击速率。 L（600次冲击），然后是10分钟在0.7秒的爆发中，组织疗法（每秒爆发1次）； 10分钟的脉冲;并通过8、6、4和2筛分MM过滤器。发现仅SWL的碎片尺寸范围很大，平均14.9±24.1％的原始石材质量剩余> 8 mm。 Ated Sonication SWL和组织疗法（方案A，B和C）的组合导致尺寸分布向较小的碎片转移，而在SWL后使用组织疗法的碎片> 8 mm。诱发的缺陷通过空化的侵蚀，可以在裂纹成核和加速的冲击波石细分中进行。这两种效果可能在交织的治疗中发挥作用（a），尽管通过残留的组织练习微泡核的屏蔽可能会限制了这些方案的有效性。传统SWL疗法的辅助手段。
Stone comminution in shock wave lithotripsy (SWL) has been documented to result from mechanical stresses conferred directly to the stone, as well as the activity of cavitational microbubbles. Studies have demonstrated that the presence of this cavitation activity is crucial for stone subdivision; however, its exact role in the comminution process remains somewhat weakly defined, in part due to the fact that it is difficult to isolate the cavitational component from the shock waves themselves. In this study, we further explored the importance of cavitation in SWL stone comminution through the use of histotripsy ultrasound therapy. Histotripsy was utilized to target model stones designed to mimic the mid-range tensile fracture strength of naturally occurring cystine calculi with controlled cavitation at strategic time points in the SWL comminution process. All SWL was applied at a peak-positive pressure (p+) of 34 MPa and a peak-negative pressure (p−) of 8 MPa; a shock rate of 1 Hz was used. Histotripsy pulses had a p− of 33 MPa and were applied at a pulse repetition frequency (PRF) of 100 Hz. Ten model stones were sonicated in-vitro with each of five different treatment schemes: A. 10 minutes SWL (600 shocks) with 0.7 seconds of histotripsy interleaved between successive shocks (totaling to 42,000 pulses); B. 10 minutes SWL (600 shocks) followed by 10 minutes histotripsy applied in 0.7 second bursts (1 burst per second, totaling to 42,000 pulses); C. 10 minutes histotripsy applied in 0.7 second bursts (42,000 pulses) followed by 10 minutes SWL (600 shocks); D. 10 minutes SWL-only (600 shocks); E. 10 minutes histotripsy-only applied in 0.7 second bursts (42,000 pulses). Following sonication, debris was collected and sieved through 8, 6, 4, and 2 mm filters. It was found that SWL-only generated a broad range of fragment sizes, with an average of 14.9 ± 24.1% of the original stone mass remaining >8 mm. Histotripsy-only eroded the surface of stones to tiny particulate debris that was small enough to pass through the finest filter used in this study (<2 mm), leaving behind a single primary stone piece (>8 mm) with mass 85.1 ± 1.6% of the original following truncated sonication. The combination of SWL and histotripsy (schemes A, B, and C) resulted in a shift in the size distribution toward smaller fragments and complete elimination of debris >8 mm. When histotripsy controlled cavitation was applied following SWL (B), the increase in exposed stone surface area afforded by shock wave stone subdivision led to enhanced cavitation erosion. When histotripsy controlled cavitation was applied prior to SWL (C), it is likely that stone surface defects induced by cavitation erosion provided sights for crack nucleation and accelerated shock wave stone subdivision. Both these effects are likely at play in the interleaved therapy (A), although shielding of shock waves by remnant histotripsy microbubble nuclei may have limited the efficacy of this scheme. Nevertheless, these results demonstrate the important role played by cavitation in the stone comminution process, and suggest that the application of controlled cavitation at strategic time points can provide an adjunct to traditional SWL therapy.