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Mike Bailey

Senior Principal Engineer

Associate Professor, Mechanical Engineering and Adjunct Assistant Professor, Urology

Email

bailey@apl.washington.edu

Phone

206-685-8618

Research Interests

Medical Ultrasound, Acoustic Cavitation

Biosketch

Dr. Bailey's current research focuses on the role of cavitation in lithotripsy (kidney stone treatment) and ultrasound surgery. He is the lead APL-UW researcher on two collaborative programs among the Laboratory, Indiana University, Moscow State University, and the California Institute of Technology to optimize acoustic waves to exploit bioeffects due to cavitation. Previously, he was one of the designers of a shock wave lithotripter developed at APL-UW to concentrate cavitation and damage on the kidney stone and not on the kidney tissue. Dr. Bailey joined APL-UW in 1996.

Education

B.S. Mechanical Engineering, Yale University, 1991

M.S. Mechanical Engineering, The University of Texas at Austin, 1994

Ph.D. Mechanical Engineering, The University of Texas at Austin, 1997

Videos

Characterizing Medical Ultrasound Sources and Fields

For every medical ultrasound transducer it's important to characterize the field it creates, whether for safety of imaging or efficacy of therapy. CIMU researchers measure a 2D acoustic pressure distribution in the beam emanating from the source transducer and then reconstruct mathematically the exact field on the surface of the transducer and in the entire 3D space.

11 Sep 2017

Mechanical Tissue Ablation with Focused Ultrasound

An experimental noninvasive surgery method uses nonlinear ultrasound pulses to liquefy tissue at remote target sites within a small focal region without damaging intervening tissues.

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23 Mar 2017

Boiling histotripsy utilizes sequences of millisecond-duration HIFU pulses with high-amplitude shocks that form at the focus by nonlinear propagation effects. Due to strong attenuation of the ultrasound energy at the shocks, these nonlinear waves rapidly heat tissue and generate millimeter-sized boiling bubbles at the focus within each pulse. Then the further interaction of subsequent shocks with the vapor cavity causes tissue disintegration into subcellular debris through the acoustic atomization mechanism.

The method was proposed at APL-UW in collaboration with Moscow State University (Russia) and now is being evaluated for various clinical applications. It has particular promise because of its important clinical advantages: the treatment of tissue volumes can be accelerated while sparing adjacent structures and not injuring intervening tissues; it generates precisely controlled mechanical lesions with sharp margins; the method can be implemented in existing clinical systems; and it can be used with real-time ultrasound imaging for targeting, guidance, and evaluation of outcomes. In addition, compared to thermal ablation, BH may lead to faster resorption of the liquefied lesion contents.

Burst Wave Lithotripsy: An Experimental Method to Fragment Kidney Stones

CIMU researchers are investigating a noninvasive method to fragment kidney stones using ultrasound pulses rather than shock waves. Consecutive acoustic cycles accumulate and concentrate energy within the stone. The technique can be 'tuned' to create small fragments, potentially improving the success rate of lithotripsy procedures.

20 Nov 2014

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Publications

2000-present and while at APL-UW

The impact of dust and confinement on fragmentation of kidney stones by shockwave lithotripsy in tissue phantoms

Randad, A., J. Ahn, W. Kreider, M.R. Bailey, J.D. Harper, M.D. Sorensen, and A.D. Maxwell, "The impact of dust and confinement on fragmentation of kidney stones by shockwave lithotripsy in tissue phantoms," J. Endourol., EOR, doi:10.1089/end.2018.0516, 2019.

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1 Feb 2019

Objective: The goal was to test whether stone composition and kidney phantom configuration affected comminution in extracorporeal shockwave lithotripsy (SWL) laboratory tests. Confinement may enhance the accumulation of dust and associated cavitation bubbles in the fluid surrounding the stone. It is known that high shockwave delivery rates in SWL are less effective because bubbles generated by one shockwave do not have sufficient time to dissolve, thereby shielding the next shockwave.

Materials and Methods: Experiments were conducted with a lithotripter coupled to a water bath. The rate of comminution was measured by weighing fragments over 2 mm at 5-minute time points. First, plaster and crystal stones were broken in four phantoms: a nylon wire mesh, an open polyvinyl chloride (PVC) cup, a closed PVC cup, and an anatomical kidney model — the phantoms have decreasing fluid volumes around the stone. Second, the fluid volume in the kidney model was flushed with water at different rates (0, 7, and 86 mL/min) to remove dust.

Results: The efficiency of breakage of stones decreases for the dust emitting plaster stones (percentage of breakage in 5 minutes decreased from 92% ± 2% [n = 3] in wire mesh to 19% ± 3% [n = 3] in model calix) with increasing confinement, but not for the calcite crystal stones that produced little dust (percentage of breakage changed from 87% ± 3% [n = 3] in wire mesh to 81% ± 3% [n = 3] in kidney model). Flushing the kidney phantom at the fastest rate improved comminution of smaller plaster stones by 27%.

Conclusions: Phantoms restricting dispersion of dust were found to affect stone breakage in SWL and in vitro experiments should replicate kidney environments. The dust around the stone and potential cavitation may shield the stone from shockwaves and reduce efficacy of SWL. Understanding of stone composition and degree of hydronephrosis could be used to adapt patient-specific protocols.

Impact of stone type on caviation in burst wave lithotripsy

Hunter, C., A.D. Maxwell, B. Cunitz, B. Dunmire, M.D. Sorensen, J.C. Williams Jr., A. Randad, M. Bailey, and W. Kreider, "Impact of stone type on caviation in burst wave lithotripsy," Proc. Mtgs. Acoust., 35, 020005, doi:10.1121/2.0000950, 2018.

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26 Dec 2018

Proceedings, 176th Meeting of the Acoustical Society of America, 5-9 November 2018, Victoria, BC, Canada.

Non-invasive kidney stone treatments such as shock wave lithotripsy (SWL) and burst wave lithotripsy (BWL) rely on the delivery of pressure waves through tissue to the stone. In both SWL and BWL, the potential to hinder comminution by exciting cavitation proximal to the stone has been reported. To elucidate how different stones alter prefocal cavitation in BWL, different natural and synthetic stones were treated in vitro using a therapy transducer operating at 350 kHz (peak negative pressure 7 MPa, pulse length 20 cycles, pulse repetition frequency 10 Hz). Stones were held in a confined volume of water designed to mimic the geometry of a kidney calyx, with the water filtered and degassed to maintain conditions for which the cavitation threshold (in the absence of a stone) matches that from in vivo observations. Stone targeting and cavitation monitoring were performed via ultrasound imaging using a diagnostic probe aligned coaxially with the therapy transducer. Quantitative differences in the extent and location of cavitation activity were observed for different stone types — e.g., stones (natural and synthetic) that are known to be porous produced larger prefocal cavitation clouds. Ongoing work will focus on correlation of such cavitation metrics with stone fragmentation.

Modeling and numerical simulation of the bubble cloud dynamics in an ultrasound field for burst wave lithotripsy

Maeda, K., T. Colonius, A. Maxwell, W. Kreider, and M. Bailey, "Modeling and numerical simulation of the bubble cloud dynamics in an ultrasound field for burst wave lithotripsy," Proc. Mtgs. Acoust., 35, 020006, doi:10.1121/2.0000946, 2018.

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26 Dec 2018

176th Meeting of the Acoustical Society of America, 5-9 November 2018, Victoria, BC, Canada.

Modeling and numerical simulation of bubble clouds induced by intense ultrasound waves are conducted to quantify the effect of cloud cavitation on burst wave lithotripsy, a proposed non-invasive alternative to shock wave lithotripsy that uses pulses of ultrasound with an amplitude of O(1) MPa and a frequency of O(100) kHz. A unidirectional acoustic source model and an Eulerian-Lagrangian method are developed for simulation of ultrasound generation from a multi-element array transducer and cavitation bubbles, respectively. Parametric simulations of the spherical bubble cloud dynamics reveal a new scaling parameter that dictates both the structure of the bubble cloud and the amplitude of the far-field, bubble-scattered acoustics. The simulation further shows that a thin layer of bubble clouds nucleated near a kidney stone model can shield up to 90% of the incoming wave energy, indicating a potential loss of efficacy during the treatment due to cavitation. Strong correlations are identified between the far-field, bubble-scattered acoustics and the magnitude of the shielding, which could be used for ultrasound monitoring of cavitation during treatments. The simulations are validated by companion experiments in vitro.

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In The News

UW researchers and Florida middle school students form unusual bond over cosmic kidney stones

GeekWire, Kellie Schmitt

Eight students from a low-income sugarcane town in South Florida spent months on a robotics project tackling kidney stones in space. Across the country, researchers at the University of Washington were studying the exact problem for NASA, embarking on clinical trials that, so far, are proving successful. The disparate groups converged this month when the students reached out to APL-UW scientists.

23 Feb 2019

The mobile ultrasound revolution: How technology is expanding this medical tool to new frontiers

GeekWire, Kellie Schmitt

Decades after Seattle led the way in portable ultrasound development, the technology has made the leap to sleek, handheld devices that can connect to a smartphone. Increasingly, researchers say, ultrasound technology will be used not just for imaging but for actual treatment of disease.

23 Jan 2019

Rock Stars: UW Researchers Take a Whack at Kidney Stone Disease

Seattle Business (page 11), Stuart Glascock

Mike Bailey led a team to develop a system to avoid surgical procedures often associated with kidney stone disease. Using long pulses of sound waves, smaller stones are pushed from the kidney safely without anesthesia.

1 Feb 2017

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Inventions

Determining a Presence of an Object

Patent Number: 10,136,835

Mike Bailey, Wei Lu, Oleg Sapozhnikov, Bryan Cunitz

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Patent

27 Nov 2018

Methods, computing devices, and computer-readable medium are described herein related to producing detection signals configured to induce an excited state of an object. A computing device may receive reflection signals, where the reflection signals correspond to at least one detection signals reflected from the object. Based on the received reflection signals, a presence of the object in the excited state may be determined. Further, an output device may provide an indication of the presence of the object in the excited state.

Ultrasound Based Method and Apparatus for Stone Detection and to Facilitate Clearance Thereof

Patent Number: 10,039,562

Mike Bailey, Bryan Cunitz, Barbrina Dunmire

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Patent

7 Aug 2018

Described herein are methods and apparatus for detecting stones by ultrasound, in which the ultrasound reflections from a stone are preferentially selected and accentuated relative to the ultrasound reflections from blood or tissue. Also described herein are methods and apparatus for applying pushing ultrasound to in vivo stones or other objects, to facilitate the removal of such in vivo objects.

Renal Needle Access Guide for Ultrasound Guided Percutaneous Nephrolithotomy

Record of Invention Number: 48366

Mike Bailey, Helen Chang, Barbrina Dunmire, Jonathan Harper, Katy Kuznetsova

Disclosure

26 Jun 2018

More Inventions

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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