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Bryan Cunitz

Limited Term Appointment - Pro Staff

Email

bwc@apl.washington.edu

Phone

206-543-6804

Education

B.A. Physics, Colby College, 1999

B.S. Engineering, Dartmouth College, 2000

M.S. Electrical Engineering, University of Washington, 2005

Videos

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

SonoMotion: A Budding Start-up Company

A research team has developed new technologies to treat kidney stone disease with an ultrasound-based system. Embraced by clinicians, their advances are now being taken to the next step: transition the prototype to an approved device that will roll into hospitals and clinics around the world.

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11 Feb 2013

At the Center for Industrial and Medical Ultrasound a team of scientists, engineers, and students has developed an ultrasound-based system that may provide an office procedure to speed the natural passage of kidney stones. The system uses commercial ultrasound components to locate stones in kidneys. It creates clear pictures of them and then applies an acoustic radiative force, repositioning stones in the kidney so they are more likely to pass naturally.

As a research team, considerable technical advancements have been made and valuable feedback and cooperation has been garnered from the user community – the clinicians. The scientists, engineers, urologists, and commercialization experts are now collaborating to take the next steps.

SonoMotion has partnered with a hardware manufacturing company and licensed the ultrasonic propulsion of kidney stones technology with the University of Washington. The next big step will be to transition the prototype system into one that will pass the rigors of FDA review and be ready to roll into hospitals and clinics around the world.

Center for Industrial and Medical Ultrasound - CIMU

CIMU is a group of scientists, engineers, and technicians dedicated to research across the field of bio-medical ultrasonics with the goal of developing technologies that will be used in a clinic to treat patients.

1 Nov 2010

Publications

2000-present and while at APL-UW

Fragmentation of stones by burst wave lithotripsy in the first 19 humans

Harper, J.D., J.E. Lingeman, R.M. Sweet, I.S. Metzler, P. Sunaryo, J.C. Williams, A.D. Maxwell, J. Thiel, B.M. Cunitz, B. Dunmire, M.R. Bailey, and M.D. Sorensen, "Fragmentation of stones by burst wave lithotripsy in the first 19 humans," J. Urol., 207, doi:10.1097/JU.0000000000002446, 2022.

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1 May 2022

We report stone comminution in the first 19 human subjects by burst wave lithotripsy (BWL), which is the transcutaneous application of focused, cyclic ultrasound pulses. This was a prospective multi-institutional feasibility study recruiting subjects undergoing clinical ureteroscopy (URS) for at least 1 stone ≤12 mm as measured on computerized tomography. During the planned URS, either before or after ureteroscope insertion, BWL was administered with a handheld transducer, and any stone fragmentation and tissue injury were observed. Up to 3 stones per subject were targeted, each for a maximum of 10 minutes. The primary effectiveness outcome was the volume percent comminution of the stone into fragments ≤2 mm. The primary safety outcome was the independent, blinded visual scoring of tissue injury from the URS video. Overall, median stone comminution was 90% (IQR 20, 100) of stone volume with 21 of 23 (91%) stones fragmented. Complete fragmentation (all fragments ≤2 mm) within 10 minutes of BWL occurred in 9 of 23 stones (39%). Of the 6 least comminuted stones, likely causative factors for decreased effectiveness included stones that were larger than the BWL beamwidth, smaller than the BWL wavelength or the introduction of air bubbles from the ureteroscope. Mild reddening of the papilla and hematuria emanating from the papilla were observed ureteroscopically. The first study of BWL in human subjects resulted in a median of 90% comminution of the total stone volume into fragments ≤2 mm within 10 minutes of BWL exposure with only mild tissue injury.

Characterization and ex vivo evaluation of an extracorporeal high-intensity focused ultrasound (HIFU) system

Zhou, Y.F., B.W. Cunitz, B. Dunmire, Y.-N. Wang, S.G. Karl, C. Warren, S. Mitchell, and J.H. Hwang, "Characterization and ex vivo evaluation of an extracorporeal high-intensity focused ultrasound (HIFU) system," J. Appl. Clin. Med. Phys., 22, 345-359, doi:10.1002/acm2.13074, 2021.

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1 Sep 2021

High-intensity focused ultrasound (HIFU) has been in clinical use for a variety of solid tumors and cancers. Accurate and reliable calibration is in a great need for clinical applications. An extracorporeal clinical HIFU system applied for the investigational device exemption (IDE) to the Food and Drug Administration (FDA) so that evaluation of its characteristics, performance, and safety was required.

The acoustic pressure and power output was characterized by a fiber optic probe and a radiation force balance, respectively, with the electrical power up to 2000 W. An in situ acoustic energy was established as the clinical protocol at the electrical power up to 500 W. Temperature elevation inside the tissue sample was measured by a thermocouple array. Generated lesion volume at different in situ acoustic energies and pathological examination of the lesions was evaluated ex vivo.

Acoustic pressure mapping showed the insignificant presence of side/grating lobes and pre- or post-focal peaks (≤–12 dB). Although distorted acoustic pressure waveform was found in the free field, the nonlinearity was reduced significantly after the beam propagating through tissue samples (i.e., the second harmonic of –11.8 dB at 500 W). Temperature elevation was <10°C at a distance of 10 mm away from a 20-mm target, which suggests the well-controlled HIFU energy deposition and no damage to the surrounding tissue. An acoustic energy in the range of 750–1250 J resulted in discrete lesions with an interval space of 5 mm between the treatment spots. Histology confirmed that the lesions represented a region of permanently damaged cells by heat fixation, without causing cell lysis by either cavitation or boiling.

Our characterization and ex vivo evaluation protocol met the IDE requirement. The in-situ acoustic energy model will be used in clinical trials to deliver almost consistent energy to the various targets.

Factors affecting tissue cavitation during burst wave lithotripsy

Maxwell, A.D., C. Hunter, B.W. Cunitz, W. Kreider, S. Totten, and Y.-N. Wang, "Factors affecting tissue cavitation during burst wave lithotripsy," Ultrasound Med. Biol., 47, 2286-2295, doi:10.1016/j.ultrasmedbio.2021.04.021, 2021.

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1 Aug 2021

Burst wave lithotripsy (BWL) is a technology under clinical investigation for non-invasive fragmentation of urinary stones. Under certain ranges of ultrasound exposure parameters, this technology can cause cavitation in tissue leading to renal injury. This study sought to measure the focal pressure amplitude needed to cause cavitation in vivo and determine its consistency in native tissue, in an implanted stone model and under different exposure parameters. The kidneys of eight pigs were exposed to transcutaneous BWL ultrasound pulses. In each kidney, two locations were targeted: the renal sinus and the kidney parenchyma. Each was exposed for 5 min at a set pressure level and parameters, and cavitation was detected using an active cavitation imaging method based on power Doppler ultrasound. The threshold was determined by incrementing the pressure amplitude up or down after each 5-min interval until cavitation occurred/subsided. The pressure thresholds were remeasured postsurgery, targeting an implanted stone or collecting space (in sham). The presence of a stone or sham surgery did not significantly impact the threshold for tissue cavitation. Targeting parenchyma instead of kidney collecting space and lowering the ultrasound pulse repetition frequency both resulted in an increased pressure threshold for cavitation.

More Publications

Inventions

Broadly Focused Ultrasonic Propulsion Probes, Systems, and Methods

Disclosed herein are ultrasonic probes and systems incorporating the probes. The probes are configured to produce an ultrasonic therapy exposure that, when applied to a kidney stone, will exert an acoustic radiation force sufficient to produce ultrasonic propulsion. Unlike previous probes configured to produce ultrasonic propulsion, however, the disclosed probes are engineered to produce a relatively large (both wide and long) therapy region effective to produce ultrasonic propulsion. This large therapy region allows the probe to move a plurality of kidney stones (or fragments from lithotripsy) in parallel, thereby providing the user the ability to clear several stones from an area simultaneously. This "broadly focused" probe is, in certain embodiments, combined in a single handheld unit with a typical ultrasound imaging probe to produce real-time imaging. Methods of using the probes and systems to move kidney stones are also provided.

Patent Number: 10,667,831

Mike Bailey, Bryan Cunitz, Barbrina Dunmire, Adam Maxwell, Oren Levy

Patent

2 Jun 2020

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.

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.

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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