Cavitation phenomena in extracorporeal microexplosion lithotripsy

Tomita, Yukio; Obara, Tetsuro; Takayama, K.; Kuwahara, Masaaki

doi:10.1007/bf01414709

Cited by 17 publications

(6 citation statements)

References 32 publications

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“…Extracorporeal Shock Wave Lithotripsy is the clinical procedure by which thousands of shock waves, emitted at roughly one per second, are focused onto kidney stones in order to break them up to a size small enough to be passed naturally from the body, or dissolved with drugs. The incident shock wave interacts with the stone in many ways, including spallation and cavitation (Zeman et al 1990;Kuwahara et al 1991;Coleman et al 1992;Lush et al 1992;Philipp et al 1993;Tomita et al 1994;Sapozhnikov et al 2001;Bailey et al 2003;Leighton 2004).…”

Section: Lithotripter Shock-induced Collapse Of An Initially Stable Bmentioning

confidence: 99%

Free-Lagrange simulations of the expansion and jetting collapse of air bubbles in water

et al. 2008

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A free-Lagrange numerical method is implemented to simulate the axisymmetric jetting collapse of air bubbles in water. This is performed for both lithotripter shock-induced collapses of initially stable bubbles, and for free-running cases where the bubble initially contains an overpressure. The code is validated using two test problems (shock-induced bubble collapse using a step shock, and shock–water column interaction) and the results are compared to numerical and experimental results. For the free-running cases, simulations are conducted for a bubble of initial radius 0.3 mm located near a rigid boundary and near an aluminium layer (planar and notched surfaces). The simulations suggest that the boundary and its distance from the bubble influence the flow dynamics, inducing bubble elongation and jetting. They also indicate stress concentration in the aluminium and the likelihood of aluminium deformation associated with bubble collapse events. For the shock-induced collapse, a lithotripter shock, consisting of 56 MPa compressive and −10 MPa tensile waves, interacts with a bubble of initial radius 0.04 mm located in a free field (case 1) and near a rigid boundary (case 2). The interaction of the shock with the bubble causes it to involute and a liquid jet is formed that achieves a velocity exceeding 1.2 km s−1 for case 1 and 2.6 km s−1 for case 2. The impact of the jet on the downstream wall of the bubble generates a blast wave with peak overpressure exceeding 1 GPa and 1.75 GPa for cases 1 and 2, respectively. The results show that the simulation technique retains sharply resolved gas/liquid interfaces regardless of the degree of geometric deformation, and reveal details of the dynamics of bubble collapse. The effects of compressibility are included for both liquid and gas phases, whereas stress distributions can be predicted within elastic–plastic solid surfaces (both planar and notched) in proximity to cavitation events. There is a movie with the online version of the paper.

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Section: Lithotripter Shock-induced Collapse Of An Initially Stable Bmentioning

confidence: 99%

Free-Lagrange simulations of the expansion and jetting collapse of air bubbles in water

et al. 2008

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“…PACS numbers: 47.55.dp,47.55.dd,43.25.Yw Shock waves in liquids are a common cause of cavitation [1][2][3][4][5], in particular when shocks are reflected and focussed [6]. Famous examples include shock-induced cavitation in lithotripsy [7,8] and the 'white crown' on the sea surface following an underwater detonation [9][10][11]. However, little is known about shock-induced cavitation inside "isolated" liquid volumes [12], which are completely bounded by a free surface.…”

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confidence: 99%

Confined shocks inside isolated liquid volumes: A new path of erosion?

et al. 2011

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The unique confinement of shock waves inside isolated liquid volumes amplifies the density of shock-liquid interactions. We investigate this universal principle through an interdisciplinary study of shock-induced cavitation inside liquid volumes, isolated in 2 and 3 dimensions. By combining high-speed visualizations of ideal water drops realized in microgravity with smoothed particle simulations, we evidence strong shock-induced cavitation at the focus of the confined shocks. We extend this analysis to ground-observations of jets and drops using an analytic model and argue that cavitation caused by trapped shocks offers a distinct mechanism of erosion in high-speed impacts ð100 ms À1 Þ.Shock waves in liquids are a common cause of cavitation, 1-5 in particular when shocks are reflected and focussed. 6 Famous examples include shock-induced cavitation in lithotripsy 7,8 and the "white crown" on the sea surface following an underwater detonation. 9-11 However, little is known about shock-induced cavitation inside "isolated" liquid volumes, 12 which are completely bounded by a free surface. The crucial feature of such systems is their unique confinement: the closed surface acts as a mirror trapping the shock and amplifying its local interaction with the fluid. Experimental hints for the importance of this mechanism for generating cavitation were provided by some of the earliest high-speed visualizations of shocked drops [Ref. 13, see reprint in Fig. 1(a)].In this letter, we study the amplification of shockinduced cavitation in liquid volumes isolated in three dimensions (3D), such as drops, and in two dimensions (2D), such as jets. Illustrations of shock-driven cavitation in both cases are provided in Fig. 1. To understand this cavitation, we perform a systematic experimental study of shock-induced cavitation inside large, spherical water drops. These drops are realized in microgravity conditions aboard parabolic flights (European Space Agency, 42nd Parabolic Flight Campaign). In parallel to those experiments, we provide a quantitative explanation of the observed cavitation patterns through numerical simulations of dissipative shocks inside spheres and derive an analytic model to predict the location of shock-induced cavitation. Thereby, we demonstrate that shock-induced cavitation in isolated volumes is a universal phenomenon. Finally, we discuss a potential implication of cavitation caused by trapped shocks for drop erosion of solid surfaces.Our microgravity experiment can be seen as an ideal laboratory for the study of shock dynamics inside stable drops. The setup [details in Ref. 15] can produce a spherical drop of demineralized water (diameter D ¼ 16-26 mm). This drop is smoothly expelled through an injector tube, which also serves as a permanent attach-point for the drop (see Fig. 2, left). A movable pair of electrodes penetrating the drop from the top in Fig. 2 releases a fast (10 ns) discharge at a specific location within the drop. This discharge forms a supersonically expanding point-plasma [physics in Ref....

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“…The methods are compared in Table 1. The electrohydraulic methods, namely, laser-induced shock-wave generation (9,10) and explosion of powder such as AgN 3 (11,12) , are the most suitable in regard to device miniaturization. A shock-wave generator using powder explosion has an advantage in terms of controlling the power of the generated shock wave, but it is still at the research stage.…”

Section: Miniaturized Eswl Device 21 Overviewmentioning

confidence: 99%

A Miniaturized Shock-Wave Device for Mounting on Forceps

Nakagawa

Tsukamoto

Arafune

et al. 2013

JBSE

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To provide shock-wave exposure with high accuracy and widen the application area of shock-wave therapy, a miniaturized shock-wave device for endoscopic surgery was developed. The shock-wave device applies an electrohydraulic mechanism for generating shock waves in light of device miniaturization and suitability for standard clinical practice. The outer diameter of the shock-wave generator is 11 mm, so it can be inserted in the body through a trocar used in endoscopic surgery or a natural orifice in the case of natural-orifice translumenal endoscopic surgery (NOTES). The distance between the shock-wave focal point and the front of the device is 10 mm. The focused shock wave was observed at the focal point by visualization with the schlieren imaging technique. The pressure at the focal point was measured, and the measurement revealed that the device can produce a peak pressure of 2.32±0.81 MPa at 2-kV discharge voltage, 3.69±1.06 MPa at 3 kV, 5.67±2.44 MPa at 4 kV, and 7.27±2.33 MPa at 5 kV.

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Cavitation phenomena in extracorporeal microexplosion lithotripsy

Cited by 17 publications

References 32 publications

Free-Lagrange simulations of the expansion and jetting collapse of air bubbles in water

Free-Lagrange simulations of the expansion and jetting collapse of air bubbles in water

Confined shocks inside isolated liquid volumes: A new path of erosion?

A Miniaturized Shock-Wave Device for Mounting on Forceps

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