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Adam Maxwell

Senior Fellow - Trainee

Email

maxwell@apl.washington.edu

Phone

206-221-6530

Videos

Mechanical Tissue Ablation with Focused Ultrasound

An experimental noninvasive surgery method uses nonlinear ultrasound pulses to liquefy tissue at remote target sites within a small focal region without damaging intervening tissues.

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23 Mar 2017

Boiling histotripsy utilizes sequences of millisecond-duration HIFU pulses with high-amplitude shocks that form at the focus by nonlinear propagation effects. Due to strong attenuation of the ultrasound energy at the shocks, these nonlinear waves rapidly heat tissue and generate millimeter-sized boiling bubbles at the focus within each pulse. Then the further interaction of subsequent shocks with the vapor cavity causes tissue disintegration into subcellular debris through the acoustic atomization mechanism.

The method was proposed at APL-UW in collaboration with Moscow State University (Russia) and now is being evaluated for various clinical applications. It has particular promise because of its important clinical advantages: the treatment of tissue volumes can be accelerated while sparing adjacent structures and not injuring intervening tissues; it generates precisely controlled mechanical lesions with sharp margins; the method can be implemented in existing clinical systems; and it can be used with real-time ultrasound imaging for targeting, guidance, and evaluation of outcomes. In addition, compared to thermal ablation, BH may lead to faster resorption of the liquefied lesion contents.

Burst Wave Lithotripsy: An Experimental Method to Fragment Kidney Stones

CIMU researchers are investigating a noninvasive method to fragment kidney stones using ultrasound pulses rather than shock waves. Consecutive acoustic cycles accumulate and concentrate energy within the stone. The technique can be 'tuned' to create small fragments, potentially improving the success rate of lithotripsy procedures.

20 Nov 2014

Publications

2000-present and while at APL-UW

Design of HIFU transducers for generating specific nonlinear ultrasound fields

Rosnitskiy, P.B., P.V. Yuldashev, O.A. Sapozhnikov, A. Maxwell, W. Kreider, M.R. Bailey, "Design of HIFU transducers for generating specific nonlinear ultrasound fields," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, doi:10.1109/TUFFC.2016.2619913, 2016.

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20 Oct 2016

Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements for the pressure levels and degree of nonlinear waveform distortion at the focus. The goal of this work was to determine transducer design parameters that produce either a specified shock amplitude in the focal waveform or specified peak pressures while still maintaining quasilinear conditions at the focus. Multiparametric nonlinear modeling based on the KZK equation with an equivalent source boundary condition was employed. Peak pressures, shock amplitudes at the focus, and corresponding source outputs were determined for different transducer geometries and levels of nonlinear distortion. Results are presented in terms of the parameters of an equivalent single-element, spherically shaped transducer. The accuracy of the method and its applicability to cases of strongly focused transducers were validated by comparing the KZK modeling data with measurements and nonlinear full-diffraction simulations for a single-element source and arrays with 7 and 256 elements. The results provide look-up data for evaluating nonlinear distortions at the focus of existing therapeutic systems as well as for guiding the design of new transducers that generate specified nonlinear fields.

Cavitation-induced damage of soft materials by focused ultrasound bursts: A fracture-based bubble dynamics model

Movahed, P., W. Greider, A.D. Maxwell, S.B. Hutchens, and J.B. Freund, "Cavitation-induced damage of soft materials by focused ultrasound bursts: A fracture-based bubble dynamics model," J. Acoust. Soc. Am., 140, 1374-1386, doi:10.1121/1.4961364, 2016.

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1 Aug 2016

A generalized Rayleigh–Plesset-type bubble dynamics model with a damage mechanism is developed for cavitation and damage of soft materials by focused ultrasound bursts. This study is linked to recent experimental observations in tissue-mimicking polyacrylamide and agar gel phantoms subjected to bursts of a kind being considered specifically for lithotripsy. These show bubble activation at multiple sites during the initial pulses. More cavities appear continuously through the course of the observations, similar to what is deduced in pig kidney tissues in shock-wave lithotripsy. Two different material models are used to represent the distinct properties of the two gel materials. The polyacrylamide gel is represented with a neo-Hookean elastic model and damaged based upon a maximum-strain criterion; the agar gel is represented with a strain-hardening Fung model and damaged according to the strain-energy-based Griffith's fracture criterion. Estimates based upon independently determined elasticity and viscosity of the two gel materials suggest that bubble confinement should be sufficient to prevent damage in the gels, and presumably injury in some tissues. Damage accumulation is therefore proposed to occur via a material fatigue, which is shown to be consistent with observed delays in widespread cavitation activity.

An ultrasonic caliper device for measuring acoustic nonlinearity

Hunter, C., O.A Sapozhnikov, A.D. Maxwell, V.A. Khokhlova, Y.-N. Wang, B. MacConaghy, and W. Kreider, "An ultrasonic caliper device for measuring acoustic nonlinearity," Phys. Procedia, 87, 93-98, doi:10.1016/j.phpro.2016.12.015, 2016.

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1 May 2016

In medical and industrial ultrasound, it is often necessary to measure the acoustic properties of a material. A specific medical application requires measurements of sound speed, attenuation, and nonlinearity to characterize livers being evaluated for transplantation. For this application, a transmission-mode caliper device is proposed in which both transmit and receive transducers are directly coupled to a test sample, the propagation distance is measured with an indicator gage, and receive waveforms are recorded for analysis. In this configuration, accurate measurements of nonlinearity present particular challenges: diffraction effects can be considerable while nonlinear distortions over short distances typically remain small. To enable simple estimates of the nonlinearity coeffcient from a quasi-linear approximation to the lossless Burgers’ equation, the calipers utilize a large transmitter and plane waves are measured at distances of 15–50 mm. Waves at 667 kHz and pressures between 0.1 and 1 MPa were generated and measured in water at different distances; the nonlinearity coeffcient of water was estimated from these measurements with a variability of approximately 10%. Ongoing efforts seek to test caliper performance in other media and improve accuracy via additional transducer calibrations.

More Publications

Design of HIFU transducers to generate specific nonlinear ultrasound fields

Khokhlova, V.A., P.V. Yuldashev, P.B. Rosnitskiy, A.D. Maxwell, W. Kreider, M.R. Bailey, and O.A. Sapozhnikov, "Design of HIFU transducers to generate specific nonlinear ultrasound fields," Phys. Proced., 87, 132-138, doi:10.1016/j.phpro.2016.12.020, 2016.

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1 May 2016

Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation of tissue. In this work, an inverse problem of determining transducer parameters to enable formation of shocks with desired amplitude at the focus is solved. The solution was obtained by performing multiple direct simulations of the parabolic Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sources as well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocks are formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90–100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University.

Bubble-induced color Doppler feedback for histotripsy tissue fractionation

Miller, R.M., X. Zhang, A.D. Maxwell, C.A. Cain, and Z. Xu, "Bubble-induced color Doppler feedback for histotripsy tissue fractionation," IEEE Trans. Ultrasoun. Ferroelect. Freq. Control, 63, 408-419, doi:10.1109/TUFFC.2016.2525859, 2016.

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1 Mar 2016

Histotripsy therapy produces cavitating bubble clouds to increasingly fractionate and eventually liquefy tissue using high-intensity ultrasound pulses. Following cavitation generated by each pulse, coherent motion of the cavitation residual nuclei can be detected using metrics formed from ultrasound color Doppler acquisitions. In this paper, three experiments were performed to investigate the characteristics of this motion as real-time feedback on histotripsy tissue fractionation. In the first experiment, bubble-induced color Doppler (BCD) and particle image velocimetry (PIV) analysis monitored the residual cavitation nuclei in the treatment region in an agarose tissue phantom treated with two-cycle histotripsy pulses at >30 MPa using a 500-kHz transducer. Both BCD and PIV results showed brief chaotic motion of the residual nuclei followed by coherent motion first moving away from the transducer and then rebounding back. Velocity measurements from both PIV and BCD agreed well, showing a monotonic increase in rebound time up to a saturation point for increased therapy dose. In a second experiment, a thin layer of red blood cells (RBC) was added to the phantom to allow quantification of the fractionation of the RBC layer to compare with BCD metrics. A strong linear correlation was observed between the fractionation level and the time to BCD peak rebound velocity over histotripsy treatment. Finally, the correlation between BCD feedback and histotripsy tissue fractionation was validated in ex vivo porcine liver evaluated histologically. BCD metrics showed strong linear correlation with fractionation progression, suggesting that BCD provides useful quantitative real-time feedback on histotripsy treatment progression.

Histotripsy methods in mechanical disintegration of tissue: Toward clinical applications

Khokhlova, V.A., J.B. Fowlkes, W.W. Roberts, G.R. Schade, Z. Xu, T.D. Khokhlova, T.L. Hall, A.D. Maxwell, Y.-N. Wang, and C.A. Cain, "Histotripsy methods in mechanical disintegration of tissue: Toward clinical applications," Int. J. Hypertherm., 31, 145-162, doi:10.3109/02656736.2015.1007538, 2015.

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1 Mar 2015

In high intensity focused ultrasound (HIFU) therapy, an ultrasound beam is focused within the body to locally affect the targeted site without damaging intervening tissues. The most common HIFU regime is thermal ablation. Recently there has been increasing interest in generating purely mechanical lesions in tissue (histotripsy). This paper provides an overview of several studies on the development of histotripsy methods toward clinical applications. Two histotripsy approaches and examples of their applications are presented. In one approach, sequences of high-amplitude, short (microsecond-long), focused ultrasound pulses periodically produce dense, energetic bubble clouds that mechanically disintegrate tissue. In an alternative approach, longer (millisecond-long) pulses with shock fronts generate boiling bubbles and the interaction of shock fronts with the resulting vapour cavity causes tissue disintegration. Recent preclinical studies on histotripsy are reviewed for treating benign prostatic hyperplasia (BPH), liver and kidney tumours, kidney stone fragmentation, enhancing anti-tumour immune response, and tissue decellularisation for regenerative medicine applications. Potential clinical advantages of the histotripsy methods are discussed. Histotripsy methods can be used to mechanically ablate a wide variety of tissues, whilst selectivity sparing structures such as large vessels. Both ultrasound and MR imaging can be used for targeting and monitoring the treatment in real time. Although the two approaches utilise different mechanisms for tissue disintegration, both have many of the same advantages and offer a promising alternative method of non-invasive surgery.

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

Purpose
We have developed a new method of lithotripsy that uses short, broadly focused bursts of ultrasound rather than shock waves to fragment stones. This study investigated the characteristics of stone comminution by burst wave lithotripsy in vitro.

Materials and Methods
Artificial and natural stones (mean 8.2±3.0 mm, range 5–15 mm) were treated with ultrasound bursts using a focused transducer in a water bath. Stones were exposed to bursts with focal pressure amplitude 𕟮.5 MPa at 200 Hz burst repetition rate until completely fragmented. Ultrasound frequencies of 170 kHz, 285 kHz, and 800 kHz were applied using 3 different transducers. The time to achieve fragmentation for each stone type was recorded, and fragment size distribution was measured by sieving.

Results
Stones exposed to ultrasound bursts were fragmented at focal pressure amplitudes 𕟴.8 MPa at 170 kHz. Fractures appeared along the stone surface, resulting in fragments separating at the surface nearest to the transducer until the stone was disintegrated. All natural and artificial stones were fragmented at the highest focal pressure of 6.5 MPa with treatment durations between a mean of 36 seconds for uric acid to 14.7 minutes for cystine stones. At a frequency of 170 kHz, the largest artificial stone fragments were <4 mm. Exposures at 285 kHz produced only fragments <2 mm, and 800 kHz produced only fragments <1 mm.

Conclusions
Stone comminution with burst wave lithotripsy is feasible as a potential noninvasive treatment method for nephrolithiasis. Adjusting the fundamental ultrasound frequency allows control of stone fragment size.

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

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.

Noninvasive ureterocele puncture using pulsed focused ultrasound: An in vitro study

Maxwell, A.D., R.S. Hsi, M.R. Bailey, P. Casale, and T.S. Lendvay, "Noninvasive ureterocele puncture using pulsed focused ultrasound: An in vitro study," J. Endourol., 28, 342-346, doi:10.1098/end.2013.0528, 2014.

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1 Mar 2014

Purpose: To evaluate the feasibility of performing noninvasive puncture of pediatric ureteroceles with cavitation-based focused ultrasound (US) (histotripsy).

Materials and Methods: A model for the ureterocele wall was developed from an excised bovine bladder wall. The model was exposed to focused US pulses in a water bath under three different US parameter sets for up to 300 seconds to create localized perforations in the wall. B-mode US imaging was used to monitor the treatment and assess potential imaging guidance and feedback.

Results: Punctures were formed between 46–300 seconds, depending on the focused US exposure parameters and model wall thickness. Puncture diameter was controllable through choice of exposure parameters and could be varied between 0.8–2.8%u2009mm mean diameter. US-induced cavitation was visible on B-mode imaging, which provided targeting and treatment feedback.

Conclusions: Cavitation-based focused US can create punctures in a model that mimics the tissue properties of a ureterocele wall, under guidance from US imaging.

Addressing nonlinear propagation effects in characterization of high intensity focused ultrasound fields and prediction of thermal and mechanical bioeffects in tissue

Khokhlova, V.A., P.V. Yuldashev, W. Kreider, O.A. Sapozhnikov, M.R. Bailey, T.D. Khokhlova, A.D. Maxwell, and L.A. Crum, "Addressing nonlinear propagation effects in characterization of high intensity focused ultrasound fields and prediction of thermal and mechanical bioeffects in tissue," J. Acoust. Soc. Am., 134, 4153, doi:10.1121/1.4831221, 2013.

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1 Nov 2013

Nonlinear propagation effects are present in most fields generated by high intensity focused ultrasound (HIFU) sources. In some newer HIFU applications, these effects are strong enough to result in the formation of high amplitude shocks that actually determine the therapy and provide a means for imaging. However, there is no standard approach yet accepted to address these effects. Here, a set of combined measurement and modeling methods to characterize nonlinear HIFU fields in water and predict acoustic pressures in tissue is presented. A characterization method includes linear acoustic holography measurements to set a boundary condition to the model and nonlinear acoustic simulations in water for increasing pressure levels at the source. A derating method to determine nonlinear focal fields with shocks in situ is based on the scaling of the source pressure for data obtained in water to compensate for attenuation losses in tissue. The accuracy of the methods is verified by comparing the results with hydrophone and time-to-boil measurements. Major effects associated with the formation of shocks are overviewed. A set of metrics for determining thermal and mechanical bioeffects is introduced and application of the proposed tools to strongly nonlinear HIFU applications is discussed.

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

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 40–200 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 12–630 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

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

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.

Rectified growth of histotripsy bubbles

Kreider, W., A.D. Maxwell, T. Khokhlova, J.C. Simon, V.A. Khokhlova, O. Sapzhnikov, and M.R. Bailey, "Rectified growth of histotripsy bubbles," Proc., Meetings on Acoustics, 19, 075035, doi:10.1121/1.4800326, 2013.

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2 Jun 2013

Histotripsy treatments use high-amplitude shock waves to fractionate tissue. Such treatments have been demonstrated using both cavitation bubbles excited with microsecond-long pulses and boiling bubbles excited for milliseconds. A common feature of both approaches is the need for bubble growth, where at 1 MHz cavitation bubbles reach maximum radii on the order of 100 microns and boiling bubbles grow to about 1 mm. To explore how histotripsy bubbles grow, a model of a single, spherical bubble that accounts for heat and mass transport was used to simulate the bubble dynamics. Results suggest that the asymmetry inherent in nonlinearly distorted waveforms can lead to rectified bubble growth, which is enhanced at elevated temperatures. Moreover, the rate of this growth is sensitive to the waveform shape, in particular the transition from the peak negative pressure to the shock front. Current efforts are focused on elucidating this behavior by obtaining an improved calibration of measured histotripsy waveforms with a fiber-optic hydrophone, using a nonlinear propagation model to assess the impact on the focal waveform of higher harmonics present at the source's surface, and photographically observing bubble growth rates.

Inventions

MRI-Guided Lithotripsy of Urinary Tract Stones

Record of Invention Number: 47984

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

Disclosure

23 Feb 2017

Combination Burst Wave Lithotripsy and Ultrasonic Propulsion for Improved Stone Fragmentation

Record of Invention Number: 47817

Adam Maxwell, Mike Bailey, Bryan Cunitz, Annie Zwaschka

Disclosure

9 Sep 2016

Methods and Devices for Improved Cavitation-Induced Drug Delivery Using Pulsed Focused Ultrasound with Shocks

Record of Invention Number: 47734

Vera Khokhlova, Joo Ha Hwang, Tatiana Khokhlova, Wayne Kreider, Adam Maxwell, Oleg Sapozhnikov

Disclosure

1 Jun 2016

More Inventions

One-dimensional Receiving Arrays to Measure 2D Lateral Pressure Distribution of Acoustic Beams Radiated by Ultrasound Sources

Record of Invention Number: 47632

Oleg Sapozhnikov, Vera Khokhlova, Wayne Kreider, Adam Maxwell

Disclosure

22 Feb 2016

Novel Probe and Workflow for Ultrasonic Propulsion

Record of Invention Number: 47322

Mike Bailey, Bryan Cunitz, Brian Dickinson, Barbrina Dunmire, Brian MacConaghy, Adam Maxwell

Disclosure

1 May 2015

Noninvasive Disintegration of Peyronie's Plaque with Focused Ultrasound

Record of Invention Number: 47233

Hunter Wessells, Mike Bailey, Mahri Haider, Tatiana Khokhlova, Frank Lee, Adam Maxwell, George Schade, Yak-Nam Wang

Disclosure

23 Feb 2015

Method for In Vivo Diagnosis of Kidney Stone Composition

Record of Invention Number: 47079

Adam Maxwell, Bryan Cunitz, Ryan Hsi

Disclosure

6 Oct 2014

Methods to Determine Optimal Ultrasound Pulse Parameters to Fragment Urinary Calculi Using Acoustic Feedback

Record of Invention Number: 47078

Adam Maxwell, Mike Bailey, Bryan Cunitz, Oleg Sapozhnikov

Disclosure

6 Oct 2014

Ultrasound Image Feedback for Lithotripsy

Record of Invention Number: 47077

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

Disclosure

6 Oct 2014

Ultrasound Technique for Trapping and Displacing Solid Objects Using a Vortex Acoustic Beam Created by a Multi-element Sector Array Transducer

Record of Invention Number: 47037

Mike Bailey, Wayne Kreider, Adam Maxwell, Oleg Sapozhnikov

Disclosure

18 Aug 2014

Ultrasound Instrumentation for Ureteroscopic and Transcutaneous Kidney Stone Removal

Record of Invention Number: 46839

Thomas Lendvay, Mike Bailey, Ryan Hsi, Brian MacConaghy, Adam Maxwell

Disclosure

4 Feb 2014

MRI-based Methods to Target, Monitor, and Quantify Thermal and Mechanical Bioeffects in Tissue Induced by High Intensity Focused Ultrasound

Record of Invention Number: 46745

Vera Khokhlova, Mike Bailey, Tanya Khokhlova, Wayne Kreider, Donghoon Lee, Adam Maxwell, George Schade

Disclosure

26 Nov 2013

Methods to Selectively Fragment and Remove Tissue While Sparing Extracellular Matrix, Vessels and Similar Structures Using Microsecond-long High Intensity Focused Ultrasound Pulses with Shocks

Record of Invention Number: 46742

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

Disclosure

18 Nov 2013

Methods to Induce Large Volumes of Mechanically Fractionated Lesions Using Therapeutic Phased Arrays

Record of Invention Number: 46733

Vera Khokhlova, Mike Bailey, Tanya Khokhlova, Wayne Kreider, Adam Maxwell, Oleg Sapozhnikov

Disclosure

8 Nov 2013

Low-Frequency Enhancement of Boiling Histotripsy

Record of Invention Number: 46730

Vera Khokhlova, Mike Bailey, Tanya Khokhlova, Wayne Kreider, Adam Maxwell, Oleg Sapozhnikov

Disclosure

7 Nov 2013

Method to Induce Transcostal Tissue Ablation using High Intensity Focused Ultrasound with Shocks

Record of Invention Number: 46728

Vera Khokhlova, Mike Bailey, Larry Crum, Wayne Kreider, Adam Maxwell, Oleg Sapozhnikov, Leonid R. Gavrilov, Petr Yuldashev

Disclosure

6 Nov 2013

Device and Procedure for Noninvasive Removal of Ureteral Stents

Record of Invention Number: 46501

Adam Maxwell, Mike Bailey, Ryan Hsi, Hunter Wessells

Disclosure

9 May 2013

Noninvasive Fragmentation of Urinary Tract Stones with Focused Ultrasound

Record of Invention Number: 46460

Adam Maxwell, Mike Bailey, Bryan Cunitz, Ryan Hsi

Disclosure

28 Mar 2013

Noninvasive Treatment of Ureteroceles with Focused Ultrasound

Record of Invention Number: 46404

Mike Bailey, Pasquale Casale, Ryan Hsi, Thomas Lendvay, Adam Maxwell

Disclosure

14 Feb 2013

Method for Noninvasive Focused Ultrasound Surgery

Record of Invention Number: 46356

Vera Khokhlova, Mike Bailey, Adam Maxwell, Oleg Sapozhnikov

Disclosure

11 Jan 2013

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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