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Mike Bailey

Senior Principal Engineer

Associate Professor, Mechanical Engineering and Adjunct Assistant Professor, Urology





Research Interests

Medical Ultrasound, Acoustic Cavitation


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.


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


Ultrasonic Kidney Stone Treatment for Pet Cats and Marine Mammals

A research kidney stone treatment system that is now undergoing clinical trials in humans was modified to noninvasively fragment stones in pet cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Veterinarian collaborators at the University of Minnesota have treated ureteral stones successfully in three cats.

The human system has also been used to treat a dolphin with a ureteral stone blockage and a harbor seal to reduce the stone burden in his kidneys.

20 Dec 2023

Ultrasonic tweezers: Technology to lift and steer solid objects in a living body

In a recent paper, a CIMU team describes successful experiments to manipulate a solid object within a living body with ultrasound beams transmitted through the skin.

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15 Jul 2020

A collaborative, international research teams developed and tuned an ultrasound transducer to create vortex shaped beams that can trap, grab, levitate, and move in three dimensions mm-scale objects. The team is working to apply this technology to their all-in-one kidney stone treatment system that, in clinical trials, uses ultrasound to non-invasively break, erode, and move stones and stone fragments out of the kidney so that they may pass naturally from the body.

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. A multi-institution, international team led by CIMU researchers is applying the method to the focal treatment of prostate tumors.

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19 Mar 2020

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.

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2000-present and while at APL-UW

Application of a novel burst wave lithotripsy and ultrasonic propulsion technology for the treatment of ureteral calculi in a bottlenose dolphin (Tursiops truncatus) and renal calculi in a harbor seal (Phoca vitulina)

Holmes, A.E., and 17 others including J. Thiel and M.R. Bailey, "Application of a novel burst wave lithotripsy and ultrasonic propulsion technology for the treatment of ureteral calculi in a bottlenose dolphin (Tursiops truncatus) and renal calculi in a harbor seal (Phoca vitulina)," Urolithiasis, 52, doi:10.1007/s00240-023-01515-6, 2024.

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8 Jan 2024

Marine mammals may develop kidney stones, which can be challenging to treat. We describe burst wave lithotripsy (BWL) and ultrasonic propulsion to treat ureteral calculi in a 48-year-old female bottlenose dolphin (Tursiops truncatus) and to reduce renal stone burden in a 23-year-old male harbor seal (Phoca vitulina). BWL and ultrasonic propulsion were delivered transcutaneously in sinusoidal ultrasound bursts to fragment and reposition stones. Targeting and monitoring were performed with real-time imaging integrated within the BWL system. Four dolphin stones were obtained and fragmented ex vivo. The dolphin case received a 10-min and a 20-min BWL treatment conducted approximately 24 h apart to treat two 8–10 mm partially obstructing right mid-ureteral stones, using oral sedation alone. For the harbor seal, while under general anesthesia, retrograde ureteroscopy attempts were unsuccessful because of ureteral tortuosity, and a 30-min BWL treatment was targeted on one 10-mm right kidney stone cluster. All 4 stones fragmented completely to < 2-mm fragments in < 20 min ex vivo. In the dolphin case, the ureteral stones appeared to fragment, spread apart, and move with ultrasonic propulsion. On post-treatment day 1, the ureteral calculi fragments shifted caudally reaching the ureteral orifice on day 9. On day 10, the calculi fragments passed, and the hydroureter resolved. In the harbor seal, the stone cluster was observed to fragment and was not visible on the post-operative computed tomography scan. The seal had gross hematuria and a day of behavior indicating stone passage but overall, an uneventful recovery. BWL and ultrasonic propulsion successfully relieved ureteral stone obstruction in a geriatric dolphin and reduced renal stone burden in a geriatric harbor seal.

Development of an automated ultrasound signal indicator of lung interstitial syndrome

Khokhlova, T.D., G.P. Thomas, J. Hall, K. Steinbock, J. Thiel, B.W. Cunitz, M.R. Bailey, L. Anderson, R. Kessler, M.K. Hall, and A.A. Adedipe, "Development of an automated ultrasound signal indicator of lung interstitial syndrome," J. Ultrasound Med., EOR, doi:10.1002/jum.16383, 2023.

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5 Dec 2023

The number and distribution of lung ultrasound (LUS) imaging artifacts termed B-lines correlate with the presence of acute lung disease such as infection, acute respiratory distress syndrome (ARDS), and pulmonary edema. Detection and interpretation of B-lines require dedicated training and is machine and operator-dependent. The goal of this study was to identify radio frequency (RF) signal features associated with B-lines in a cohort of patients with cardiogenic pulmonary edema. A quantitative signal indicator could then be used in a single-element, non-imaging, wearable, automated lung ultrasound sensor (LUSS) for continuous hands-free monitoring of lung fluid.

Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats

Maxwell, A.D., G.W. Kim, E. Furrow, J.P. Lulich, M. Torre, B. MacConaghy, E. Lynch, D.F. Leotta, Y.-N. Wang, M.S. Borofsky, and M.R. Bailey, "Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats," BMC Vet. Res., 141, doi:10.1186/s12917-023-03705-1, 2023.

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2 Sep 2023

Upper urinary tract stones are increasingly prevalent in pet cats and are difficult to manage. Surgical procedures to address obstructing ureteroliths have short- and long-term complications, and medical therapies (e.g., fluid diuresis and smooth muscle relaxants) are infrequently effective. Burst wave lithotripsy is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now undergoing human clinical trials in awake unanesthetized subjects.

In this study, we designed and performed in vitro testing of a modified burst wave lithotripsy system to noninvasively fragment stones in cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Prototypes were fabricated and tested in a benchtop model using 35 natural calcium oxalate monohydrate stones from cats. In an initial experiment, burst wave lithotripsy was performed using peak ultrasound pressures of 7.3 (n = 10), 8.0 (n = 5), or 8.9 MPa (n = 10) for up to 30 min. Fourteen of 25 stones fragmented to < 1 mm within the 30 min. In a second experiment, burst wave lithotripsy was performed using a second transducer and peak ultrasound pressure of 8.0 MPa (n = 10) for up to 50 min. In the second experiment, 9 of 10 stones fragmented to < 1 mm within the 50 min. Across both experiments, an average of 73–97% of stone mass could be reduced to fragments < 1 mm. A third experiment found negligible injury with in vivo exposure of kidneys and ureters in a porcine animal model.

These data support further evaluation of burst wave lithotripsy as a noninvasive intervention for obstructing ureteroliths in cats.

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In The News

Kidney stone breakthrough procedure at UW called 'game changer' for patients (video)

KOMO News, Preston Phillips

A groundbreaking medical procedure for those with kidney stones will soon be offered at the University of Washington after more than two decades of research. It will also give astronauts the go ahead they need from NASA to travel to Mars.

10 May 2023

NEJM Study Suggests If Having Kidney Stone Surgery, Treat All the Stones

Medical Research .com, Marie Benz

Mike Bailey is interviewed about the recently published paper, saying, "When getting stone surgery, treat all stones."

11 Aug 2022

Leaving small kidney stones behind causes problems later

UW Medicine Newsroom, Barbara Clements

When surgeons remove patients' kidney stones, they typically leave behind small stones that appear not to be causing problems.

A new randomized controlled study showed, however, that leaving these asymptomatic stones behind significantly increases the risk of a patient's relapse in the following five years.

11 Aug 2022

More News Items


High Intensity Focused Ultrasound Systems for Treating Tissue

Inventors: Y.-N. Wang, M.R. Bailey, T.D. Khokhlova (Seattle), W. Kreider, A.D. Maxwell, G.R. Schade (Seattle), and V.A. Khokhlova

Patent Number: 11,857,813

Yak-Nam Wang, Mike Bailey, Wayne Kreider, Adam Maxwell, Vera Khokhlova


2 Jan 2024

Noninvasive Fragmentation of Urinary Tract Stones with Focused Ultrasound

Patent Number: 11,583,299

Adam Maxwell, Bryan Cunitz, Wayne Kreider, Oleg Sapozhnikov, Mike Bailey


21 Feb 2023

Confinement or Movement of an Object Using Focused Ultrasound Waves to Generate an Ultrasound Intensity Well

Patent Number: 11,580,945

Adam Maxwell, Oleg Sapozhnikov, Wayne Kreider, Mike Bailey


14 Feb 2023

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