Bryan Cunitz Limited Term Appointment - Pro Staff 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
Projects
Ultrasonic Detection and Propulsion of Kidney Stones An ultrasound-based system assembled from commercial components and customized software control locates kidney stones, applies an acoustic radiative force, and repositions the stones so they are more likely to pass naturally. Watch urologist test the system. |
1 Feb 2019
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Radiation Pressure from Ultrasound Helps Kidney Stones Pass A commercial ultrasound imager and a focused ultrasound device are combined to visualize and push a kidney stone from the lower pole of the kidney to the uretropelvic junction to facilitate its passing. |
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Videos
Ultrasonic Propulsion of Residual Kidney Stone Framents Ultrasonic propulsion, an investigational kidney stone treatment for awake un-anesthetized patients, sweeps stone fragments toward the ureter to facilitate their natural passage through the urine. |
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9 Sep 2024
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Ultrasonic propulsion, an investigational kidney stone treatment for awake un-anesthetized patients, sweeps stone fragments toward the ureter to facilitate their natural passage through the urine. |
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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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
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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. |
Publications |
2000-present and while at APL-UW |
Randomized controlled trial of ultrasonic propulsion-facilitated clearance of residual kidney stone fragments vs. observation Sorensen, M.D., and 16 others including B. Dunmire, J. Thiel, B.W. Cunitz, J.C. Kucewicz, and M.R. Bailey, "Randomized controlled trial of ultrasonic propulsion-facilitated clearance of residual kidney stone fragments vs. observation," J. Urol., EOR, doi:10.1097/JU.0000000000004186, 2024. |
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15 Aug 2024 |
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Ultrasonic propulsion is an investigational procedure for awake patients. Our purpose was to evaluate whether ultrasonic propulsion to facilitate residual kidney stone fragment clearance reduced relapse. |
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 |
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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. |
Dual-mode 1D linear ultrasound array for image-guided drug delivery enhancement without ultrasound contrast agents Williams, R.P., M.M. Karzova, P.V. Yuldashev, A.Z. Kaloev, F.A. Nartov, V.A. Khokhlova, B.W. Cunitz, K.P. Morrison, and T.D. Khokhlova, "Dual-mode 1D linear ultrasound array for image-guided drug delivery enhancement without ultrasound contrast agents," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 70, 693-707, doi:10.1109/TUFFC.2023.3268603, 2023. |
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19 Apr 2023 |
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Pulsed high-intensity focused ultrasound (pHIFU) uses nonlinearly distorted millisecond-long ultrasound pulses of moderate intensity to induce inertial cavitation in tissue without administration of contrast agents. The resulting mechanical disruption permeabilizes the tissue and enhances the diffusion of systemically administered drugs. This is especially beneficial for tissues with poor perfusion such as pancreatic tumors. Here we characterize the performance of a dual-mode ultrasound array designed for image-guided pHIFU therapies in producing inertial cavitation and ultrasound imaging. The 64-element linear array (1.071 MHz, aperture of 14.8 mm x 51.2 mm, and pitch of 0.8 mm) with elevational focal length of 50 mm was driven by the Verasonics V-1 ultrasound system with extended burst option. The attainable focal pressures and electronic steering range in linear and nonlinear operating regimes (relevant to pHIFU treatments) were characterized through hydrophone measurements, acoustic holography, and numerical simulations. The steering range at ±10% from the nominal focal pressure was found to be ±±6 mm axially and ±11 mm azimuthally. Focal waveforms with shock fronts of up to 45 MPa, and peak negative pressures up to 9 MPa were achieved at focusing distances of 3875 mm from the array. Cavitation behaviors induced by isolated 1 ms pHIFU pulses in optically transparent agarose gel phantoms were observed by high-speed photography across a range of excitation amplitudes and focal distances. For all focusing configurations the appearance of sparse, stationary cavitation bubbles occurred at the same P_ threshold of 2 MPa. As the output level increased, a qualitative change in cavitation behavior occurred, to pairs and sets of proliferating bubbles. The pressure P_ at which this transition was observed corresponded to substantial nonlinear distortion and shock formation in the focal region and was thus dependent on the focal distance of the beam ranging within 34 MPa for azimuthal F-numbers of 0.74 to 1.5. The array was capable of B-mode imaging at 1.5 MHz of centimeter-sized targets in phantoms and in vivo pig tissues at depths of 3 cm to 7 cm, relevant to pHIFU applications in abdominal targets. |
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 |
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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 |
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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. |
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 |
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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. |
A prototype therapy system for boiling histotripsy in abdominal targets based on a 256-element spiral array Bawiec, C.R., T.D. Khokhlova, O.A Sapozhnikov, P.B. Rosnitskiy, B.W. Cunitz, M.A. Ghanem, C. Hunter, W. Kreider, G.R. Schade, P.V. Yuldashev, and V.A. Khokhlova, "A prototype therapy system for boiling histotripsy in abdominal targets based on a 256-element spiral array," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 68, 1496-1510, doi:10.1109/TUFFC.2020.3036580, 2021. |
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1 May 2021 |
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Boiling histotripsy (BH) uses millisecond-long ultrasound (US) pulses with high-amplitude shocks to mechanically fractionate tissue with potential for real-time lesion monitoring by US imaging. For BH treatments of abdominal organs, a high-power multielement phased array system capable of electronic focus steering and aberration correction for body wall inhomogeneities is needed. In this work, a preclinical BH system was built comprising a custom 256-element 1.5-MHz phased array (Imasonic, Besançon, France) with a central opening for mounting an imaging probe. The array was electronically matched to a Verasonics research US system with a 1.2-kW external power source. Driving electronics and software of the system were modified to provide a pulse average acoustic power of 2.2 kW sustained for 10 ms with a 12-Hz repetition rate for delivering BH exposures. System performance was characterized by hydrophone measurements in water combined with nonlinear wave simulations based on the Westervelt equation. Fully developed shocks of 100-MPa amplitude are formed at the focus at 275-W acoustic power. Electronic steering capabilities of the array were evaluated for shock-producing conditions to determine power compensation strategies that equalize BH exposures at multiple focal locations across the planned treatment volume. The system was used to produce continuous volumetric BH lesions in ex vivo bovine liver with 1-mm focus spacing, 10-ms pulselength, five pulses/focus, and 1% duty cycle. |
First in-human burst wave lithotripsy for kidney stone comminution: Initial two case studies Harper, J.D., I. Metzler, M.K. Hall, T.T. Chen, A.D. Maxwell, B.W. Cunitz, B. Dunmire, J. Thiel, J.C. Williams, M.R. Bailey, and M.D. Sorensen, "First in-human burst wave lithotripsy for kidney stone comminution: Initial two case studies," J. Endourol., 35, 506-511, doi:10.1089/end.2020.0725, 2021. |
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1 Apr 2021 |
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Purpose: To test the effectiveness (Participant A) and tolerability (Participant B) of urinary stone comminution in the first in-human trial of a new technology, burst wave lithotripsy (BWL). |
In vitro evaluation of urinary stone comminution with a clinical burst wave lithotripsy system Ramesh, S., T.T. Chen, A.D. Maxwell, B.W. Cunitz, B. Dunmire, J. Thiel, J.C. Williams, A. Gardner, Z. Liu, I. Metzler, J.D. Harper, M.D. Sorensen, and M.R. Bailey, "In vitro evaluation of urinary stone comminution with a clinical burst wave lithotripsy system," J. Endourol., 34, 1167-1173, doi:10.1089/end.2019.0873, 2020. |
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1 Nov 2020 |
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Objective: Our goals were to validate stone comminution with an investigational burst wave lithotripsy (BWL) system in patient-relevant conditions and to evaluate the use of ultrasonic propulsion to move a stone or fragments to aid in observing the treatment endpoint. |
Noninvasive acoustic manipulation of objects in a living body Ghanem, M.A., A.D. Maxwell, Y.-N. Wang, B.W. Cunitz, V.A. Khokhlova, O.A. Sopozhnikov, and M.R. Bailey, "Noninvasive acoustic manipulation of objects in a living body," Proc. Nat. Acad. Sci. USA, 117, 16,848-16,855, doi:10.1073/pnas.2001779117, 2020. |
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21 Jul 2020 |
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In certain medical applications, transmitting an ultrasound beam through the skin to manipulate a solid object within the human body would be beneficial. Such applications include, for example, controlling an ingestible camera or expelling a kidney stone. In this paper, ultrasound beams of specific shapes were designed by numerical modeling and produced using a phased array. These beams were shown to levitate and electronically steer solid objects (3-mm-diameter glass spheres), along preprogrammed paths, in a water bath, and in the urinary bladders of live pigs. Deviation from the intended path was on average <10%. No injury was found on the bladder wall or intervening tissue. |
Evidence of microbubbles on kidney stones in humans Simon, J.C., J.R. Holm, J. Thiel, B. Dunmire, B.W. Cunitz, and M.R. Bailey, "Evidence of microbubbles on kidney stones in humans," Ultrasound Med. Biol., 46, 1802-1807, doi:10.1016/j.ultrasmedbio.2020.02.010, 2020. |
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1 Jul 2020 |
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The color Doppler ultrasound twinkling artifact has been found to improve detection of kidney stones with ultrasound; however, it appears on only ~60% of stones. Evidence from ex vivo kidney stones suggests twinkling arises from microbubbles stabilized in crevices on the stone surface. Yet it is unknown whether these bubbles are present on stones in humans. Here, we used a research ultrasound system to quantify twinkling in humans with kidney stones in a hyperbaric chamber. Eight human patients with non-obstructive kidney stones previously observed to twinkle were exposed to a maximum pressure of 4 atmospheres absolute (ATA) while breathing air, except during the 10-min pause at 1.6 ATA and while the pressure decreased to 1 ATA, during which patients breathed oxygen to minimize the risk of decompression sickness. A paired one-way t-test was used to compare the mean twinkle power at each pressure pause with baseline twinkling, with p < 0.05 considered to indicate significance. Results revealed that exposure to 3 and 4 ATA of pressure significantly reduced twinkle power by averages of 35% and 39%, respectively, in 7 patients (p = 0.04); data from the eighth patient were excluded because of corruption. This study supports the theory that microbubbles are present on kidney stones in humans. |
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 |
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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. |
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 |
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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. |
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 |
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Proceedings, 176th Meeting of the Acoustical Society of America, 5-9 November 2018, Victoria, BC, Canada. |
Update on clinical trials of kidney stone repositioning and preclinical results of stone breaking with one system Bailey, M.R., Y.-N. Wang, W. Kreider, J.C. Dai, B.W. Cunitz, J.D. Harper, H. Chang, M.D. Sorensen, Z. Liu, O. Levy, B. Dunmire, and A.D. Maxwell, "Update on clinical trials of kidney stone repositioning and preclinical results of stone breaking with one system," Proc. Mtgs. Acoust, 35, 020004, doi:10.1121/2.0000949, 2018. |
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21 Dec 2018 |
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176th Meeting of the Acoustical Society of America 5-9 November 2018, Victoria, BC, Canada. |
An in vivo demonstration of efficacy and acute safety of burst wave lithotripsy using a porcine model Wang, Y.-N., W. Kreider, C. Hunter, B.W. Cunitz, J. Thiel, F. Starr, J.C. Dai, Y. Nazari, D. Lee, J.C. Williams, M.R. Bailey, and A.D. Maxwell, "An in vivo demonstration of efficacy and acute safety of burst wave lithotripsy using a porcine model," Proc. Mtgs. Acoust., 35, 02009, doi:10.1121/2.0000975, 2018. |
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5 Nov 2018 |
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Proceedings, 176th Meeting of the Acoustical Society of America, 5-9 November 2018, Victoria, BC, Canada. |
Field characterization and compensation of vibrational nonuniformity for a 256-element focused ultrasound phased array Ghanem, M.A., A.D. Maxwell, W. Kreider, B.W. Cunitz, V.A. Khokhlova, O.A. Sapozhnikov, and M.R. Bailey, "Field characterization and compensation of vibrational nonuniformity for a 256-element focused ultrasound phased array," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 65, 1618-1630, doi:10.1109/TUFFC.2018.2851188, 2018. |
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1 Sep 2018 |
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Multielement focused ultrasound phased arrays have been used in therapeutic applications to treat large tissue volumes by electronic steering of the focus, to target multiple simultaneous foci, and to correct aberration caused by inhomogeneous tissue pathways. There is an increasing interest in using arrays to generate more complex beam shapes and corresponding acoustic radiation force patterns for manipulation of particles such as kidney stones. Toward this end, experimental and computational tools are needed to enable accurate delivery of desired transducer vibrations and corresponding ultrasound fields. The purpose of this paper was to characterize the vibrations of a 256-element array at 1.5 MHz, implement strategies to compensate for variability, and test the ability to generate specified vortex beams that are relevant to particle manipulation. The characterization of the array output was performed in water using both element-by-element measurements at the focus of the array and holography measurements for which all the elements were excited simultaneously. Both methods were used to quantify each element’s output so that the power of each element could be equalized. Vortex beams generated using both compensation strategies were measured and compared to the Rayleigh integral simulations of fields generated by an idealized array based on the manufacturer’s specifications. Although both approaches improved beam axisymmetry, compensation based on holography measurements had half the error relative to the simulation results in comparison to the element-by-element method. |
Combined burst wave lithotripsy and ultrasonic propulsion fo improved urinary stone fragmentation Zwaschka, T.A., J.S. Ahn, B.W. Cunitz, M.R. Bailey, B. Dunmire, M.D. Sorensen, J.D. Harper, and A.D. Maxwell, "Combined burst wave lithotripsy and ultrasonic propulsion fo improved urinary stone fragmentation," J. Endourol., 32, 344-349, doi:10.1089/end.2017.0675, 2018. |
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1 Apr 2018 |
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Purpose |
PD37-09 kidney stone contrast with color-Doppler twinkling artifact as a function of mechanical index Cunitz, B., J. Dai, M. Sorenson, R. Sweet, B. Dunmire, J. Thiel, M. Bruce, M. Bailey, Z. Liu, and J. Harper, "PD37-09 kidney stone contrast with color-Doppler twinkling artifact as a function of mechanical index," J. Urol., 199, e734, doi:10.1016/j.juro.2018.02.1744, 2018. |
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1 Apr 2018 |
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Kidney stones can exhibit a twinkling artifact under color-flow Doppler ultrasound. There has been much work that suggests the mechanism for this artifact is micron sized bubbles trapped in the cracks of the stone cavitating from the incident Doppler pulses. We hypothesize that the signal-to-clutter ratio (SCR) of stone-to-background in Doppler mode increases with the ultrasound mechanical index (MI), a metric of the likelihood of cavitation, and that a minimum MI is needed for visibility under Doppler. |
Effect of stone size and composition on ultrasonic propulsion ex vivo Janssen, K.M., T.C. Brand, M.R. Bailey, B.W. Cunitz, J.D. Harper, M.D. Sorensen, and B. Dunmire, "Effect of stone size and composition on ultrasonic propulsion ex vivo," Urology, 111, 225-229, doi:10.1016/j.urology.2017.09.013, 2018. |
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1 Jan 2018 |
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Objective |
Characterizing the acoustic output of an ultrasonic propulsion device for urinary stones Cunitz, B.W., B. Dunmire, and M.R. Bailey, "Characterizing the acoustic output of an ultrasonic propulsion device for urinary stones," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 64, 1818-1827, doi:10.1109/TUFFC.2017.2758647, 2017. |
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1 Dec 2017 |
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A noninvasive ultrasound (US) system to facilitate the passage of small kidney stones has been developed. The device incorporates a software-based US platform programmed with brightness mode and Doppler for visualizing stones, plus long duration focused pulses for repositioning stones using the same transducer. This paper characterizes the acoustic outputs of the ultrasonic propulsion device. Though the application and outputs are unique, measurements were performed based on the regulatory standards for both diagnostic US and extracorporeal lithotripters. The extended length of the pulse, time varying pressure output over the pulse, the use of focused targeting, and the need to regulate the output at shallow depths, however, required modifications to the traditional acoustic measurement methods. Output parameters included spatial-peak intensities, mechanical index (MI), thermal index, pulse energy, focal geometry, and target accuracy. The imaging and Doppler operating modes of the system meet the Food and Drug Administration acoustic power and intensity limits for diagnostic US device. Push mode operates at a maximum MI of 2.2, which is above the limit of 1.9 for diagnostic US, but well below any lithotripsy device and an ISPTA of 548 mW/cm2, which is below the 720-mW/cm2 limit for diagnostic US. |
Design and characterization of a 2-dimensional focused 1.5-MHz ultrasound array with a compact spiral arrangement of 256 circular elements Sapozhnikov, O., M. Ghanem, A. Maxwell, P. Rosnitskiy, P. Yuldashev, W. Kreider, B. Cunitz, M. Bailey, and V. Khokhlova, "Design and characterization of a 2-dimensional focused 1.5-MHz ultrasound array with a compact spiral arrangement of 256 circular elements," Proc., IEEE International Ultrasonics Symposium, 6-9 September, Washington, D.C., doi:10.1109/ULTSYM.2017.8092165 (IEEE, 2017). |
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2 Nov 2017 |
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Multi-element ultrasound arrays are increasingly used in clinical practice for both imaging and therapy. In therapy, they allow electronic steering, aberration correction, and focusing. To avoid grating lobes, an important requirement for such an array is the absence of periodicity in the arrangement of the elements. A convenient solution is the arrangement of the elements along spirals. The objective of this work was to design, fabricate, and characterize an array for boiling histotripsy applications that is capable of generating shock waves in the focus of up to 100 MPa peak pressure while having a reasonable electronic steering range. |
Imaging in situ human kidney stones with the color Doppler ultrasound twinkling artifact Simon, J., B. Dunmire, B. Cunitz, O. Sapozhnikov, J. Thiel, J. Holm, and M. Bailey, "Imaging in situ human kidney stones with the color Doppler ultrasound twinkling artifact," Proc., IEEE International Ultrasonics Symposium, 6-9 September, Washington, D.C., doi:10.1109/ULTSYM.2017.8092599 (IEEE, 2017). |
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2 Nov 2017 |
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Hyperbaric pressures of 3100 atmospheres absolute (ATA) have been shown to reduce the color Doppler ultrasound twinkling artifact on ex vivo human kidney stones, leading to the hypothesis that surface crevice microbubbles cause twinkling. Similarly supportive for the crevice bubble hypothesis is the suppression of kidney stone twinkling in animals breathing elevated levels of carbon dioxide. However, it is unclear whether stable microbubbles can exist on the surface of kidney stones in the human body. For the first time, we investigate the effect of hyperbaric pressure on in situ human kidney stones to determine whether stable microbubbles exist as measured by the color Doppler ultrasound twinkling artifact. |
Preclinical safety and effectiveness of a longer beam and burst duration for ultrasonic repositioning of urinary stones Dunmire, B., K.M. Janssen, T.C. Brand, B.W. Cunitz, Y.-N. Wang, J.C. Simon, F. Starr, H. Denny Liggitt, J. Thiel, J.D. Harper, M.D. Sorensen, and M.R. Bailey, "Preclinical safety and effectiveness of a longer beam and burst duration for ultrasonic repositioning of urinary stones," Proc., IEEE International Ultrasonics Symposium, 6-9 September 2017, Washington, D.C., doi:10.1109/ULTSYM.2017.8092038 (IEEE, 2017). |
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2 Nov 2017 |
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In the first-in-human trial of ultrasonic propulsion, subjects passed collections of residual stone fragments after repositioning with a C5-2 probe. Here, effectiveness and safety in moving multiple fragments is compared between the C5-2 and a custom SC-50 probe that produces a longer beam and burst duration. |
Quantification of renal stone contrast with ultrasound in human subjects Cunitz, B.W., J.D. Harper, M.D. Sorensen, Y.A. Haider, J. Thiel, P.C. May, Z. Liu, M.R. Bailey, B. Dunmire, and M. Bruce, "Quantification of renal stone contrast with ultrasound in human subjects," J. Endourol., 31, 1123-1130, doi:10.1089/end.2017.0404, 2017. |
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1 Nov 2017 |
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Purpose: Greater visual contrast between calculi and tissue would improve ultrasound (US) imaging of urolithiasis and potentially expand clinical use. The color Doppler twinkling artifact has been suggested to provide enhanced contrast of stones compared with brightness mode (B-mode) imaging, but results are variable. This work provides the first quantitative measure of stone contrast in humans for B-mode and color Doppler mode, forming the basis to improve US for the detection of stones. |
Safety and effectiveness of a longer focal beam and burst duration in ultrasonic propulsion for repositioning urinary stones and fragments Janssen, K.M., T.C. Brand, B.W. Cunitz, Y.-N. Wang, J.C. Simon, F. Starr, H.D. Liggitt, J. Thiel, M.D. Sorensen, J.D. Harper, M.R. Bailey, and B. Dunmire, "Safety and effectiveness of a longer focal beam and burst duration in ultrasonic propulsion for repositioning urinary stones and fragments," J. Endourol., 31, 793-799, doi:10.1089/end.2017.0167, 2017. |
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1 Aug 2017 |
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Purpose: In the first-in-human trial of ultrasonic propulsion, subjects passed collections of residual stone fragments repositioned with a C5-2 probe. Here, effectiveness and safety in moving multiple fragments are compared between the C5-2 and a custom (SC-50) probe that produces a longer focal beam and burst duration. |
Effect of carbon dioxide on the twinkling artifact in ultrasound imaging of kidney stones: A pilot study Simon, J.C., Y.-N. Wang, B.W. Cunitz, J. Thiel, F. Starr, Z. Liu, and M.R. Bailey, "Effect of carbon dioxide on the twinkling artifact in ultrasound imaging of kidney stones: A pilot study," Ultrasound Med. Biol. 43, 877-883, doi:10.1016/j.ultrasmedbio.2016.12.010, 2017. |
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1 May 2017 |
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Bone demineralization, dehydration and stasis put astronauts at increased risk of forming kidney stones in space. The color-Doppler ultrasound "twinkling artifact," which highlights kidney stones with color, can make stones readily detectable with ultrasound; however, our previous results suggest twinkling is caused by microbubbles on the stone surface which could be affected by the elevated levels of carbon dioxide found on space vehicles. Four pigs were implanted with kidney stones and imaged with ultrasound while the anesthetic carrier gas oscillated between oxygen and air containing 0.8% carbon dioxide. On exposure of the pigs to 0.8% carbon dioxide, twinkling was significantly reduced after 925 min and recovered when the carrier gas returned to oxygen. These trends repeated when pigs were again exposed to 0.8% carbon dioxide followed by oxygen. The reduction of twinkling caused by exposure to elevated carbon dioxide may make kidney stone detection with twinkling difficult in current space vehicles. |
Shock formation and nonlinear saturation effects in the ultrasound field of a diagnostic curvilinear probe Karzova, M.M., P.V. Yuldashev, O.A. Sapozhnikov, V.A. Khokhlova, B.W. Cunitz, W. Kreider, and M.R. Bailey, "Shock formation and nonlinear saturation effects in the ultrasound field of a diagnostic curvilinear probe," J. Acoust. Soc. Am., 141, 2327-2337, doi:10.1121/1.4979261, 2017. |
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1 Apr 2017 |
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Newer imaging and therapeutic ultrasound technologies may benefit from in situ pressure levels higher than conventional diagnostic ultrasound. One example is the recently developed use of ultrasonic radiation force to move kidney stones and residual fragments out of the urinary collecting system. A commercial diagnostic 2.3 MHz C5-2 array probe has been used to deliver the acoustic pushing pulses. The probe is a curvilinear array comprising 128 elements equally spaced along a convex cylindrical surface. The effectiveness of the treatment can be increased by using higher transducer output to provide a stronger pushing force; however nonlinear acoustic saturation can be a limiting factor. In this work nonlinear propagation effects were analyzed for the C5-2 transducer using a combined measurement and modeling approach. Simulations were based on the three-dimensional Westervelt equation with the boundary condition set to match low power measurements of the acoustic pressure field. Nonlinear focal waveforms simulated for different numbers of operating elements of the array at several output power levels were compared to fiber-optic hydrophone measurements and were found to be in good agreement. It was shown that saturation effects do limit the acoustic pressure in the focal region of a diagnostic imaging probe. |
First-in-human clinical trial of ultrasonic propulsion of kidney stones Harper, J.D., B.W. Cunitz, B. Dunmire, F.C. Lee, M.D. Sorensen, R.S. Hsi, J. Thiel, H. Wessells, J.E. Lingeman, and M.R. Bailey, "First-in-human clinical trial of ultrasonic propulsion of kidney stones," J. Urol., 195, 956-964, doi:10.1016/j.juro.2015.10.131, 2016. |
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1 Apr 2016 |
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Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcutaneously to reposition kidney stones. We report the findings from the first human investigational trial of ultrasonic propulsion toward the applications of expelling small stones and dislodging large obstructing stones. |
Use of the acoustic shadow width to determine kidney stone size with ultrasound Dunmire, B., J.D. Harper, B.W. Cunitz, F.C. Lee, R. Hsi, Z. Liu, M.R. Bailey, and M.D. Sorensen, "Use of the acoustic shadow width to determine kidney stone size with ultrasound," J. Urol., 195, 171-176, doi:10.1016/j.juro.2015.05.111, 2016. |
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1 Jan 2016 |
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Ultrasound is known to overestimate kidney stone size. We explored measuring the acoustic shadow behind kidney stones combined with different ultrasound imaging modalities to improve stone sizing accuracy. A total of 45 calcium oxalate monohydrate stones were imaged in vitro at 3 different depths with the 3 different ultrasound imaging modalities of conventional ray line, spatial compound and harmonic imaging. The width of the stone and the width of the acoustic shadow were measured by 4 operators blinded to the true size of the stone. |
Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion Oweis, G.F., B.L. Dunmire, B.W. Cunitz, and M.R. Bailey, "Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion," Proc., 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 25-29 August, Milan, Italy, 2576-2579, doi:10.1109/EMBC.2015.7318918 (IEEE, 2015). |
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25 Aug 2015 |
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Transcutaneous focused ultrasound (US) is used to propel kidney stones using acoustic radiation force. It is important to estimate the level of heating generated at the stone/tissue interface for safety assessment. An in-vitro experiment is conducted to measure the temperature rise in a tissue-mimicking phantom with an embedded artificial stone and subjected to a focused beam from an imaging US array. A novel optical-imaging-based thermometry method is described using an optically clear tissue phantom. Measurements are compared to the output from a fine wire thermocouple placed on the stone surface. The optical method has good sensitivity, and it does not suffer from artificial viscous heating typically observed with invasive probes and thermocouples. |
Tools to improve the accuracy of kidney stone sizing with ultrasound Dunmire, B., F.C. Lee, R.S. Hsi, B.W. Cunitz, M. Paun, M.R. Bailey, M.D. Sorensen, and J.D. Harper, "Tools to improve the accuracy of kidney stone sizing with ultrasound," J. Endourol. 29, 147-152, doi:, 2015. |
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30 Jan 2015 |
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Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to evaluate the overestimation of stone size with US in an in vitro water bath model and investigate methods to reduce overestimation. |
Fragmentation of urinary calculi in vitro by burst wave lithotripsy Maxwell, A.D., B.W. Cunitz, W. Kreider, O.A. Sapozhnikov, R.S. Hsi, J.D. Harper, M.R. Bailey, and M.D. Sorensen, "Fragmentation of urinary calculi in vitro by burst wave lithotripsy," J. Urol., 193, 338-344, doi:10.1016/j.juro.2014.08.009, 2015. |
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1 Jan 2015 |
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Purpose |
Development and testing of an image-guided prototype system for the comminution of kidney stones using burst wave lithotripsy Cunitz, B., A. Maxwell, W. Kreider, O. Sapozhnikov, F. Lee, J. Harper, M. Sorenson, and M. Bailey, "Development and testing of an image-guided prototype system for the comminution of kidney stones using burst wave lithotripsy," J. Acoust. Soc. Am., 136, 2193, doi:10.1121/1.4899951, 2014. |
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1 Oct 2014 |
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Burst wave lithotripsy is a novel technology that uses focused, sinusoidal bursts of ultrasound to fragment kidney stones. Prior research laid the groundwork to design an extracorporeal, image-guided probe for in-vivo testing and potentially human clinical testing. Toward this end, a 12-element 330 kHz array transducer was designed and built. The probe frequency, geometry, and shape were designed to break stones up to 1 cm in diameter into fragments <2 mm. A custom amplifier capable of generating output bursts up to 3 kV was built to drive the array. To facilitate image guidance, the transducer array was designed with a central hole to accommodate co-axial attachment of an HDI P4-2 probe. Custom B-mode and Doppler imaging sequences were developed and synchronized on a Verasonics ultrasound engine to enable real-time stone targeting and cavitation detection, Preliminary data suggest that natural stones will exhibit Doppler %u201Ctwinkling%u201D artifact in the BWL focus and that the Doppler power increases as the stone begins to fragment. This feedback allows accurate stone targeting while both types of imaging sequences can also detect cavitation in bulk tissue that may lead to injury. |
Preclinical safety and effectiveness studies of ultrasonic propulsion of kidney stones Harper, J.D., B. Dunmire, Y.-N. Wang, J.C. Simon, D. Liggitt, M. Paun, B.W. Cunitz, F. Starr, M.R. Bailey, K.L. Penniston, F.C. Lee, R.S. Hsi, and M.D. Sorensen, "Preclinical safety and effectiveness studies of ultrasonic propulsion of kidney stones," Urology, 84, 484-489, doi:10.1016/j.urology.2014.04.041, 2014. |
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1 Aug 2014 |
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Objective |
Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model Khokhlova, T.D., Y.-N. Wang, J.C. Simon, B.W. Cunitz, F. Starr, M. Paun, L.A. Crum, M.R. Bailey, and V.A. Khokhlova, "Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model," P. Natl. Acad. Sci. USA, 111, 8161-8166, doi:10.1073/pnas.1318355111, 2014. |
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3 Jun 2014 |
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The clinical use of high intensity focused ultrasound (HIFU) therapy for noninvasive tissue ablation has been recently gaining momentum. In HIFU, ultrasound energy from an extracorporeal source is focused within the body to ablate tissue at the focus while leaving the surrounding organs and tissues unaffected. Most HIFU therapies are designed to use heating effects resulting from the absorption of ultrasound by tissue to create a thermally coagulated treatment volume. Although this approach is often successful, it has its limitations, such as the heat sink effect caused by the presence of a large blood vessel near the treatment area or heating of the ribs in the transcostal applications. HIFU-induced bubbles provide an alternative means to destroy the target tissue by mechanical disruption or, at its extreme, local fractionation of tissue within the focal region. Here, we demonstrate the feasibility of a recently developed approach to HIFU-induced ultrasound-guided tissue fractionation in an in vivo pig model. In this approach, termed boiling histotripsy, a millimeter-sized boiling bubble is generated by ultrasound and further interacts with the ultrasound field to fractionate porcine liver tissue into subcellular debris without inducing further thermal effects. Tissue selectivity, demonstrated by boiling histotripsy, allows for the treatment of tissue immediately adjacent to major blood vessels and other connective tissue structures. Furthermore, boiling histotripsy would benefit the clinical applications, in which it is important to accelerate resorption or passage of the ablated tissue volume, diminish pressure on the surrounding organs that causes discomfort, or insert openings between tissues. |
Focused ultrasound to displace renal calculi: Threshold for tissue injury Wang, Y.-N., J.C. Simon, B.W. Cunitz, F.L. Starr, M. Paun, D.H. Liggitt, A.P. Evan, J.A. McAteer, Z. Liu, B. Dunmire, and M.R. Bailey, "Focused ultrasound to displace renal calculi: Threshold for tissue injury," J. Therapeut. Ultrasound, 2, doi:10.1186/2050-5736-2-5, 2014. |
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31 Mar 2014 |
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The global prevalence and incidence of renal calculi is reported to be increasing. Of the patients that undergo surgical intervention, nearly half experience symptomatic complications associated with stone fragments that are not passed and require follow-up surgical intervention. In a clinical simulation using a clinical prototype, ultrasonic propulsion was proven effective at repositioning kidney stones in pigs. The use of ultrasound to reposition smaller stones or stone fragments to a location that facilitates spontaneous clearance could therefore improve stone-free rates. The goal of this study was to determine an injury threshold under which stones could be safely repositioned. |
Content and face validation of a curriculum for ultrasonic propulsion of calculi in a human renal model Hsi, R.S., B. Dunmire, B.W. Cunitz, X. He, M.D. Sorensen, J.D. Harper, M.R. Bailey, and T.S. Lendvay, "Content and face validation of a curriculum for ultrasonic propulsion of calculi in a human renal model," J. Endourol., 28, 459-463, doi:10.1089/end.2013.0589, 2014. |
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20 Mar 2014 |
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Purpose: Ultrasonic propulsion to reposition urinary tract calculi requires knowledge about ultrasound image capture, device manipulation, and interpretation. The purpose of this study was to validate a cognitive and technical skills curriculum to teach urologists ultrasonic propulsion to reposition kidney stones in tissue phantoms. |
Comparison of tissue injury from focused ultrasonic propulsion of kidney stones versus extracorporeal shock wave lithotripsy Connors, B.A., A.P. Evan, P.M. Blomgren, R.S. Hsi, J.D. Harper, M.D. Sorensen, Y.-N. Wang, J.C. Simon, M. Paun, F. Starr, B.W. Cunitz, M.R. Bailey, and J.E. Lingeman, "Comparison of tissue injury from focused ultrasonic propulsion of kidney stones versus extracorporeal shock wave lithotripsy," J. Urol., 191, 235-241, doi:10.1016/j.juro.2013.07.087, 2014. |
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1 Jan 2014 |
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Focused ultrasonic propulsion is a new noninvasive technique designed to move kidney stones and stone fragments out of the urinary collecting system. However, to our knowledge the extent of tissue injury associated with this technique is not known. We quantitated the amount of tissue injury produced by focused ultrasonic propulsion under simulated clinical treatment conditions and under conditions of higher power or continuous duty cycles. We compared those results to extracorporeal shock wave lithotripsy injury. |
An ultrasound system to identify and characterize kidney stones Cunitz, B.W., B.L. Dunmire, M.D. Sorensen, R. Hsi, F. Lee, O.A. Sapozhnikov, J.D. Harper, and M. Bailey, "An ultrasound system to identify and characterize kidney stones," J. Acoust. Soc. Am., 134, 3976, doi:10.1121/1.4830485, 2013. |
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1 Nov 2013 |
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Ultrasound imaging has tissue and blood imaging modes. This report describes development of a kidney stone imaging mode. Two plane pulses generate a B-mode image. Overlaid in color are regions of high decorrelation between the pulses. Our previous data [UMB, 39, 1026-1038 (2013)] indicate the pulses excite bubbles on the stone surface, which causes the decorrelation. As such this mode automatically identifies stones in the image while scanning at a high frame rate. Further in a control box placed on the stone, highly focused beams are scanned across the stone and a harmonic B-mode image is produced to sharpen the lateral resolution. This mode is used to refine the size and shape of the stone. The first mode is used to aid visualization of stones. Our team is also using it to target and track stones that move with respiration during shock wave lithotripsy (SWL) and as an indicator of stone susceptibility to SWL since surface bubbles contribute to comminution. Improved stone sizing by the second mode aids treatment planning, and resolution of surface roughness is another indicator of stone fragility. |
Fragmentation of kidney stones in vitro by focused ultrasound bursts without shock waves Maxwell, A.D., B.W. Cunitz, W. Kreider, O.A. Sapozhnikov, R.S. Hsi, M.D. Sorensen, J.D. Harper, and M.R. Bailey, "Fragmentation of kidney stones in vitro by focused ultrasound bursts without shock waves," J. Acoust. Soc. Am., 134, 4183, doi:10.1121/1.4831340, 2013. |
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1 Nov 2013 |
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Shock wave lithotripsy (SWL) is the most common procedure for treatment of kidney stones. SWL noninvasively delivers high-energy focused shocks to fracture stones into passable fragments. We have recently observed that lower-amplitude, sinusoidal bursts of ultrasound can generate similar fracture of stones. This work investigated the characteristics of stone fragmentation for natural (uric acid, struvite, calcium oxalate, and cystine) and artificial stones treated by ultrasound bursts. Stones were fixed in position in a degassed water tank and exposed to 10-cycle bursts from a 200-kHz transducer with a pressure amplitude of p ≤ 6.5 MPa, delivered at a rate of 40200 Hz. Exposures caused progressive fractures in the stone surface leading to fragments up to 3 mm. Treatment of artificial stones at different frequencies exhibited an inverse relationship between the resulting fragment sizes and ultrasound frequency. All artificial and natural types of stones tested could be fragmented, but the comminution rate varied significantly with stone composition over a range of 12630 mg/min. These data suggest that stones can be controllably fragmented by sinusoidal ultrasound bursts, which may offer an alternative treatment strategy to SWL. |
Holography and numerical projection methods for characterizing the three-dimensional acoustic fields of arrays in continuous-wave and transient regimes Kreider, W., A.D. Maxwell, P.V. Yuldashev, B.W. Cunitz, B. Dunmire, O.A. Sapozhnikov, and V.A. Khokhlova, "Holography and numerical projection methods for characterizing the three-dimensional acoustic fields of arrays in continuous-wave and transient regimes," J. Acoust. Soc. Am., 134, 4153, doi:10.1121/1.4831222, 2013. |
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1 Nov 2013 |
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The use of projection methods is increasingly accepted as a standard way of characterizing the 3D fields generated by medical ultrasound sources. When combined with hydrophone measurements of pressure amplitude and phase over a surface transverse to the wave propagation, numerical projection can be used to reconstruct 3D fields that account for operational details and imperfections of the source. Here, we use holography measurements to characterize the fields generated by two array transducers with different geometries and modes of operation. First, a seven-element, high-power therapy transducer is characterized in the continuous-wave regime using holography measurements and nonlinear forward-projection calculations. Second, a C5-2 imaging probe (Philips Healthcare) with 128 elements is characterized in the transient regime using holography measurements and linear projection calculations. Results from the numerical projections for both sources are compared with independent hydrophone measurements of select waveforms, including shocked focal waveforms for the therapy transducer. Accurate 3D field representations have been confirmed, though a notable sensitivity to hydrophone calibrations is revealed. Uncertainties associated with this approach are discussed toward the development of holography measurements combined with numerical projections as a standard metrological tool. |
Kidney stone fracture by surface waves generated with focused ultrasound tone bursts Sapozhnikov, O.A., A.D. Maxwell, W. Kreider, B.W. Cunitz, and M.R. Bailey, "Kidney stone fracture by surface waves generated with focused ultrasound tone bursts," J. Acoust. Soc. Am., 134, 4184, doi:10.1121/1.4831341, 2013. |
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1 Nov 2013 |
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Previous studies have provided insight into the physical mechanisms of stone fracture in shock wave lithotripsy. Broadly focused shocks efficiently generate shear waves in the stone leading to internal tensile stresses, which in concert with cavitation at the stone surface, cause cracks to form and propagate. Here, we propose a separate mechanism by which stones may fragment from sinusoidal ultrasound bursts without shocks. A numerical elastic wave model was used to simulate propagation of tone bursts through a cylindrical stone at a frequency between 0.15 and 2 MHz. Results suggest that bursts undergo mode conversion into surface waves on the stone that continually create significant stresses well after the exposure is terminated. Experimental exposures of artificial cylindrical stones to focused burst waves in vitro produced periodic fractures along the stone surface. The fracture spacing and resulting fragment sizes corresponded well with the spacing of stresses caused by surface waves in simulation at different frequencies. These results indicate surface waves may be an important factor in fragmentation of stones by focused tone bursts and suggest that the resulting stone fragment sizes may be controlled by ultrasound frequency. |
Ultrasound intensity to propel stones from the kidney is below the threshold for renal injury Wang, Y.-N., J.C. Simon, B. Cunitz, F. Starr, M. Paun, D. Liggit, A. Evan, J. McAteer, J. Williams, Z. Liu, P. Kaczkowski, R. Hsi, M. Sorensen, J. Harper, and M.R. Bailey, "Ultrasound intensity to propel stones from the kidney is below the threshold for renal injury," Proc., Meetings on Acoustics, 19, 075066, doi:10.1121/1.4800361, 2013. |
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3 Jun 2013 |
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Therapeutic ultrasound has an increasing number of applications in urology, including shockwave lithotripsy, stone propulsion, tissue ablation, and hemostasis. However, the threshold of renal injury using ultrasound is unknown. The goal of this study was to determine kidney injury thresholds for a range of intensities between diagnostic and ablative therapeutic ultrasound. A 2 MHz annular array generating spatial peak pulse average intensities (ISPPA) up to 28,000 W/cm2 in water was placed on the surface of in vivo porcine kidneys and focused on the adjacent parenchyma. Treatments consisted of pulses of 100 μs duration triggered every 3 ms for 10 minutes at various intensities. The perfusion-fixed tissue was scored by 3 blinded independent experts. Above a threshold of 16,620 W/cm2, the majority of injury observed included emulsification, necrosis and hemorrhage. Below this threshold, almost all injury presented as focal cell and tubular swelling and/or degeneration. These findings provide evidence for a wide range of potentially therapeutic ultrasound intensities that has a low probability of causing injury. While this study did not examine all combinations of treatment parameters of therapeutic ultrasound, tissue injury appears dose-dependent. |
Focused ultrasound to expel calculi from the kidney: Safety and efficacy of a clinical prototype device Harper, J.D., M.D. Sorensen, B.W. Cunitz, Y.-N. Wang, J.C. Simon, F. Starr, M. Paun, B. Dunmire, H.D. Liggitt, A.P. Evan, J.A. McAteer, R.S. Hsi, and M.R. Bailey, "Focused ultrasound to expel calculi from the kidney: Safety and efficacy of a clinical prototype device," J. Urol., 190, 1090-1095, doi:10.1016/j.juro.2013.03.120, 2013. |
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9 Apr 2013 |
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Purpose |
Focused ultrasound to expel calculi from the kidney Shah, A., J.D. Harper, B.W. Cunitz, Y.-N. Wang, M. Paun, J.C. Simon, W. Lu, P.J. Kaczkowski, and M.R. Bailey, "Focused ultrasound to expel calculi from the kidney," J. Urol., 187, 739-743, doi:10.1016/j.juro.2011.09.144, 2012. |
1 Feb 2012 |
Characterization of nonlinearly distorted ultrasound waves in water using broadband laser vibrometry Sapozhnikov, O.A., B.W. Cunitz, and M.R. Bailey, "Characterization of nonlinearly distorted ultrasound waves in water using broadband laser vibrometry," J. Acoust. Soc. Am., 129, 2678, doi:10.1121/1.3588977, 2011. |
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1 Apr 2011 |
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Laser vibrometry is a practical method to detect surface displacement. The method enables a direct measurement of acoustic field parameters such as acoustic particle displacement or acoustic particle velocity. Unlike other sensors, e.g., hydrophones, laser vibrometers are completely non-contact. Such devices are capable of measuring displacements from centimeters to sub nanometers at frequencies from near dc to 10 s of megahertz and have been proven to establish a primary standard for calibrating hydrophones [Bacon, IEEE Trans. UFFC, 35 (1988)]. In this technique, an ultrasonic transducer radiates an acoustic wave which is detected by a thin plastic membrane - a pellicle. The pellicle is effectively transparent to the acoustic beam so that the vibration of the pellicle follows the particle motion in the sound wave, but is reflective to the optical beam of the vibrometer allowing for a measurement. The present talk will report on measurements of nonlinearly distorted sawtooth waves in water performed with two commercial Polytec laser vibrometers: a scanning 24 MHz bandwidth system and a non-scanning 600 MHz bandwidth system. It is shown that appropriately chosen optical targets - pellicle or thick glass block with flat sides - allow resolution of both shock front and the smooth part of the waveform. |
Prototype for expulsion of kidney stones with focused ultrasound Shah, A., J.D. Harper, B.W. Cunitz, J.C. Kucewicz, Y.N. Wang, J.C. Simon, W. Lu, P.J. Kaczkowski, and M.R. Bailey, "Prototype for expulsion of kidney stones with focused ultrasound," J. Acoust. Soc. Am., 129, 2376, doi:10.1121/1.3587694, 2011. |
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1 Apr 2011 |
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Residual fragments remain in over 50% of treatments for lower pole kidney stones. A second-generation device based on a diagnostic ultrasound system and scanhead has been developed with a unique algorithm for stone detection and the capability to focus ultrasound to expel residual fragments. Focused ultrasound was applied to a bead on string in a water tank as well as to human stones (<5 mm) implanted in the lower pole of a live porcine model via retrograde ureteroscopy. Histological samples were collected and scored in a blinded fashion for therapeutic exposures and for super-therapeutic levels. The in-vitro bead was visually observed to move under focused ultrasound. Even with progressive manual displacement of the bead, the system continuously tracked and caused bead movement in real time. In the live porcine model, stones were expelled from the lower pole to the ureteropelvic junction in seconds to minutes using pulses at a duty factor of 0.02 and 8 W total acoustic power. Injury was observed no more frequently than in controls. Occurrence of injury rose slightly above control at a duty factor of 0.02 and 80 W and at a duty factor of 1 and 8 W. |
In vitro examination of nonlinear heat deposition in HIFU lesion formation Kackzkowski, P., M. Andrew, A. Brayman, S. Kargl, B. Cunitz, C. Lafon, V. Khokhlova, and L.A. Crum, "In vitro examination of nonlinear heat deposition in HIFU lesion formation," in Therapeutic Ultrasound, Proceedings of the 2nd International symposium, M.A. Andrew, L.A. Crum, and S. Vaezy, eds., 341-352 (American Institute of Physics Press, 2003). |
1 Jun 2003 |
High-intensity focused ultrasound (HIFU) array system for image-guided ablative therapy (IGAT) Kaczkowski, P.J., G.W. Keilman, B.W. Cunitz, R.W. Martin, S. Vaezy, and L.A. Crum, "High-intensity focused ultrasound (HIFU) array system for image-guided ablative therapy (IGAT)," Proceed., SPIE, 4954, 209-219, doi:10.1117/12.476539, 2003. |
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26 Jan 2003 |
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Recent interest in using High Intensity Focused Ultrasound (HIFU) for surgical applications such as hemostasis and tissue necrosis has stimulated the development of image-guided systems for non-invasive HIFU therapy. Seeking an all-ultrasound therapeutic modality, we have developed a clinical HIFU system comprising an integrated applicator that permits precisely registered HIFU therapy delivery and high quality ultrasound imaging using two separate arrays, a multi-channel signal generator and RF amplifier system, and a software program that provides the clinician with a graphical overlay of the ultrasound image and therapeutic protocol controls. Electronic phasing of a 32 element 2 MHz HIFU annular array allows adjusting the focus within the range of about 4 to 12 cm from the face. A central opening in the HIFU transducer permits mounting a commercial medical imaging scanhead (ATL P7-4) that is held in place within a special housing. This mechanical fixture ensures precise coaxial registration between the HIFU transducer and the image plane of the imaging probe. Recent enhancements include development of an acoustic lens using numerical simulations for use with a 5-element array. Our image-guided therapy system is very flexible and enables exploration of a variety of new HIFU therapy delivery and monitoring approaches in the search for safe, effective, and efficient treatment protocols. |
In The News
Pushing kidney stone fragments reduces stones' recurrence UW Medicine News Using ultrasound to reposition the smaller grains significantly lowers patients’ returns to the operating room, a study finds. |
12 Sep 2024
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Expelling stones with ultrasonic propulsion Nature Reviews Urology, Rebecca Kelsey Ultrasonic propulsion can be used to reposition kidney stones and facilitate the passage of stone fragments, according to a new study. |
17 Nov 2015
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2014 Awards of Excellence recognize campus, community contributions UW News and Information The University of Washington honored the contributions and achievements of faculty, staff, distinguished alumni and top scholars during the 44th annual Awards of Excellence ceremony Thursday, June 12. |
12 Jun 2014
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Inventions
Noninvasive Fragmentation of Urinary Tract Stones with Focused Ultrasound Patent Number: 11,583,299 Adam Maxwell, Bryan Cunitz, Wayne Kreider, Oleg Sapozhnikov, Mike Bailey |
Patent
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21 Feb 2023
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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 |
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2 Jun 2020
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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
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9 Apr 2019
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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
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27 Nov 2018
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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 |
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Patent
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7 Aug 2018
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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. |
Pulse Amplifier for Driving Ultrasound Transducers Patent Number: 9,867,999 Adam Maxwell, Bryan Cunitz, Mike Bailey, Vera Khokhlova, Timothy Hall |
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Patent
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16 Jan 2018
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Embodiments of the invention include improved radiofrequency (RF) pulse amplifier systems that incorporate an energy array comprising multiple capacitors connected in parallel. The energy array extends the maximum length of pulses and the maximum achievable peak power output of the amplifier when compared to similar systems. Embodiments also include systems comprising the amplifier configured to drive a load, wherein the load may include one or more ultrasound (e.g., piezoelectric) transducers Related methods of using the amplifier are also provided. |
Ultrasound Based Method and Apparatus for Stone Detection and to Facilitate Clearance Thereof Patent Number: 9,597,103 Mike Bailey, John Kucewicz, Barbrina Dunmire, Neil Owen, Bryan Cunitz |
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Patent
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21 Mar 2017
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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. |
Ultrasound based method and apparatus for stone detection and to facilitate clearance thereof Patent Number: 9,204,859 Mike Bailey, Bryan Cunitz, Barbrina Dunmire, John Kucewicz, Oleg Sapozhnikov |
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Patent
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8 Dec 2015
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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. |