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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

Evaluation of renal stone comminution and injury by burst wave lithotripsy in a pig model

Maxwell, A.D., Y.-N. Wang, W. Kreider, B.W. Cunitz, F. Starr, D. Lee, Y. Nazari, J.C. Williams Jr., M.R. Bailey, and M.D. Sorensen, "Evaluation of renal stone comminution and injury by burst wave lithotripsy in a pig model," J. Endourol., 33, doi:10.1089/end.2018.0886, 2019.

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15 Oct 2019

Burst wave lithotripsy is an experimental technology to noninvasively fragment kidney stones with focused bursts of ultrasound (US). This study evaluated the safety and effectiveness of specific lithotripsy parameters in a porcine model of nephrolithiasis.

A 6- to 7-mm human kidney stone was surgically implanted in each kidney of three pigs. A burst wave lithotripsy US transducer with an inline US imager was coupled to the flank and the lithotripter focus was aligned with the stone. Each stone was exposed to burst wave lithotripsy at 6.5 to 7 MPa focal pressure for 30 minutes under real-time image guidance. After treatment, the kidneys were removed for gross, histologic, and MRI assessment. Stone fragments were retrieved from the kidney to determine the mass comminuted to pieces <2 mm.

On average, 87% of the stone mass was reduced to fragments <2 mm. In three of five treatments, stones were completely comminuted to <2-mm fragments. In two of five treatments, stones were partially disintegrated, but larger fragments remained. One stone was not treated because no suitable acoustic window was identified. No injury was detected through gross, histologic, or MRI examination in the parenchymal tissue, although petechial damage and surface erosion were identified on the urothelium of the collecting system limited to the area around the stone.

Burst wave lithotripsy can consistently produce stone fragments small enough to spontaneously pass by transcutaneous administration of US pulses. The data suggest that such exposures produce minimal injury to the kidney and urinary tract.

Quantitative assessment of effectiveness of ultrasonic propulsion of kidney stones

Dai, J.C., M.D. Sorensen, H.C. Chang, P.C. Samson, B. Dunmire, B.W. Cunitz, J. Thiel, Z. Liu, M.R. Bailey, and J.D. Harper, "Quantitative assessment of effectiveness of ultrasonic propulsion of kidney stones," J. Endourol., 33, doi:10.1089/end.2019.0340, 2019.

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15 Oct 2019

Ultrasonic propulsion is an investigative modality to noninvasively image and reposition urinary stones. Our goals were to test safety and effectiveness of new acoustic exposure conditions from a new transducer, and to use simultaneous ureteroscopic and ultrasonic observation to quantify stone repositioning.

During operation, ultrasonic propulsion was applied transcutaneously, whereas stone targets were visualized ureteroscopically. Exposures were 350 kHz frequency, ≤200 W/cm2 focal intensity, and ≤3-second bursts per push. Ureteroscope and ultrasound (US) videos were recorded. Video clips with and without stone motion were randomized and scored for motion ≥3 mm by independent reviewers blinded to the exposures. Subjects were followed with telephone calls, imaging, and chart review for adverse events.

The investigative treatment was used in 18 subjects and 19 kidneys. A total of 62 stone targets were treated ranging in size from a collection of "dust" to 15 mm. Subjects received an average of 17 ñ 14 propulsion bursts (per kidney) for a total average exposure time of 40 ñ 40 seconds. Independent reviewers scored at least one stone movement ≥3 mm in 18 of 19 kidneys (95%) from the ureteroscope videos and in 15 of 19 kidneys (79%) from the US videos. This difference was probably because of motion out of the US imaging plane. Treatment repositioned stones in two cases that would have otherwise required basket repositioning. No serious adverse events were observed with the device or procedure.

Ultrasonic propulsion was shown to be safe, and it effectively repositioned stones in 95% of kidneys despite positioning and access restrictions caused by working in an operating room on anesthetized subjects.

Quantification of acoustic radiation forces on solid objects in fluid

Ghanem, M.A., A.D. Maxwell, O.A. Sapozhnikov, V.A. Khokhlova, and M.R. Bailey, "Quantification of acoustic radiation forces on solid objects in fluid," Phys. Rev. Appl., 12, doi:10.1103/PhysRevApplied.12.044076, 2019.

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1 Oct 2019

Theoretical models allow design of acoustic traps to manipulate objects with radiation force. A model of the acoustic radiation force by an arbitrary beam on a solid object is validated against measurement. The lateral force in water of different acoustic beams is measured and calculated for spheres of different diameters (2–6 wavelengths λ in water) and compositions. This is the first effort to validate a general model, to quantify the lateral force on a range of objects, and to electronically steer large or dense objects with a single-sided transducer. Vortex beams and two other beam shapes having a ring-shaped pressure field in the focal plane are synthesized in water by a 1.5-MHz, 256-element focused array. Spherical targets (glass, brass, ceramic, 2–6 mm dia.) are placed on an acoustically transparent plastic plate that is normal to the acoustic beam axis and rigidly attached to the array. Each sphere is trapped in the beam as the array with the attached plate is rotated until the sphere falls from the acoustic trap because of gravity. Calculated and measured maximum obtained angles agree on average to within 22%. The maximum lateral force occurs when the target diameter equals the beam width; however, objects up to 40% larger than the beam width are trapped. The lateral force is comparable to the gravitation force on spheres up to 90 mg (0.0009 N) at beam powers on the order of 10 W. As a step toward manipulating objects, the beams are used to trap and electronically steer the spheres along a two-dimensional path.

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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

Focused Ultrasound Apparatus and Methods of Use

Patent Number: 10,350,439

Adam Maxwell, Mike Bailey

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Patent

16 Jul 2019

Methods for diagnosing a pathologic tissue membrane, as well as a focused ultrasound apparatus and methods of treatment are disclosed to perform ureterocele puncture noninvasively using focused ultrasound-generated cavitation or boiling bubbles to controllably erode a hole through the tissue. An example ultrasound apparatus may include (a) a therapy transducer having a treatment surface, wherein the therapy transducer comprises a plurality of electrically isolated sections, (b) at least one concave acoustic lens defining a therapy aperture in the treatment surface of the therapy transducer, (c) an imaging aperture defined by either the treatment surface of the therapy transducer or by the at least one concave acoustic lens and (d) an ultrasound imaging probe axially aligned with a central axis of the therapy aperture.

Device and Method to Break Urinary Stones in Pets

Record of Invention Number: 48640

Mike Bailey, Dan Leotta, Elizabeth Lynch, Brian MacConaghy, Adam Maxwell

Disclosure

28 May 2019

Easy 3D Ultrasound Imaging and Volume Quantification

Record of Invention Number: 48367

Mike Bailey, Bryan Cunitz, Dan Leotta

Disclosure

28 May 2019

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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