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Wayne Kreider

Senior Engineer

Email

wkreider@apl.uw.edu

Phone

206-897-1814

Education

Bachelor of Science Engineering Science & Mechanics, Virginia Tech, 1993

Master of Science Engineering Mechanics, Virginia Tech, 1995

Doctor of Philosophy Bioengineering, University of Washington, 2008

Publications

2000-present and while at APL-UW

Pilot in vivo studies on transcutaneous boiling histotripsy in porcine liver and kidney

Khokhlova, T.D., G.R. Schade, Y.-N. Wang, S.V. Buravkov, V.P. Chernikov, J.C. Simon, F. Starr, A.D. Maxwell, M.R. Bailey, W. Kreider, and V.A. Khokhlova, "Pilot in vivo studies on transcutaneous boiling histotripsy in porcine liver and kidney," Sci. Rep., 9, 20176, doi:10.1038/s41598-019-56658-7, 2019.

More Info

27 Dec 2019

Boiling histotripsy (BH) is a High Intensity Focused Ultrasound (HIFU) method for precise mechanical disintegration of target tissue using millisecond-long pulses containing shocks. BH treatments with real-time ultrasound (US) guidance allowed by BH-generated bubbles were previously demonstrated ex vivo and in vivo in exposed porcine liver and small animals. Here, the feasibility of US-guided transabdominal and partially transcostal BH ablation of kidney and liver in an acute in vivo swine model was evaluated for 6 animals. BH parameters were: 1.5 MHz frequency, 5–30 pulses of 1–10 ms duration per focus, 1% duty cycle, peak acoustic powers 0.9–3.8 kW, sonication foci spaced 1–1.5 mm apart in a rectangular grid with 5–15 mm linear dimensions. In kidneys, well-demarcated volumetric BH lesions were generated without respiratory gating and renal medulla and collecting system were more resistant to BH than cortex. The treatment was accelerated 10-fold by using shorter BH pulses of larger peak power without affecting the quality of tissue fractionation. In liver, respiratory motion and aberrations from subcutaneous fat affected the treatment but increasing the peak power provided successful lesion generation. These data indicate BH is a promising technology for transabdominal and transcostal mechanical ablation of tumors in kidney and liver.

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.

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., 33, doi:10.1089/end.2018.0516, 2019.

More Info

1 May 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.

More Publications

Inventions

Noninvasive Fragmentation of Urinary Tract Stones with Focused Ultrasound

Patent Number: 10,251,657

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

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Patent

9 Apr 2019

Methods, computing devices, and a computer-readable medium are described herein related to fragmenting or comminuting an object in a subject using a burst wave lithotripsy (BWL) waveform. A computing device, such a computing device coupled to a transducer, may carry out functions for producing a BWL waveform. The computing device may determine a burst frequency for a number of bursts in the BWL waveform, where the number of bursts includes a number of cycles. Further, the computing device may determine a cycle frequency for the number of cycles. Yet further, the computing device may determine a pressure amplitude for the BWL waveform, where the pressure amplitude is less than or equal to 8 MPa. In addition, the computing device may determine a time period for producing the BWL waveform.

Audio Feedback for Improving the Accuracy of BWL Targeting

Record of Invention Number: 48254

Mike Bailey, Bryan Cunitz, Barbrina Dunmire, Christopher Hunter, Wayne Kreider, Adam Maxwell, Yak-Nam Wang

Disclosure

25 Jan 2018

Methods and Systems for Non-invasive Treatment of Tissue Using High Intensity Focused Ultrasound Therapy

Patent Number: 9,700,742

Michael Canney, Mike Bailey, Larry Crum, Joo Ha Hwang, Tatiana Khokhlova, Vera Khokhlova, Wayne Kreider, Oleg Sapozhnikov

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Patent

11 Jul 2017

Methods and systems for non-invasive treatment of tissue using high intensity focused ultrasound ("HIFU") therapy. A method of non-invasively treating tissue in accordance with an embodiment of the present technology, for example, can include positioning a focal plane of an ultrasound source at a target site in tissue. The ultrasound source can be configured to emit HIFU waves. The method can further include pulsing ultrasound energy from the ultrasound source toward the target site, and generating shock waves in the tissue to induce boiling of the tissue at the target site within milliseconds. The boiling of the tissue at least substantially emulsifies the tissue.

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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