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Francesco Curra

Principal Engineer

Assistant Professor, Bioengineering

Email

fcurra@apl.washington.edu

Phone

206-543-9848

Publications

2000-present and while at APL-UW

Ultrasound-based targeting and monitoring of high intensity focused ultrasound fields

Curra, F.P., and N. Owen, "Ultrasound-based targeting and monitoring of high intensity focused ultrasound fields," J. Acoust. Soc. Am., 129, 2439, doi: 10.1121/1.3587980, 2011.

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1 Apr 2011

A new method to address the challenging tasks of image-guidance, targeting, and treatment monitoring during HIFU treatments is presented. The approach, enabled by the use of a novel multi-layer PZT-PVDF array with broad receive bandwidth in conjunction with a programmable ultrasound engine, uses the passive-mode received echoes of the imaging array with a custom pixel-based beamforming for HIFU focal tracking and targeting, allowing real-time two-dimensional (2D) B-mode visualization of the HIFU beam. Temperature monitoring during treatment is based on acoustic nonlinear propagation theory and the physical relationship of sound speed and attenuation to frequency and temperature. The harmonics-rich received echoes are processed differentially, encoded into an RGB additive color channel, beamformed, and overlayed in color over regular B-mode images. Dynamic local temperature changes in the region of interest become visible as the 2D color image changes from frame to frame. Preliminary results on beam visualization and temperature estimations during HIFU exposure in ex-vivo muscle tissue will be presented.

Effect of elastic waves in the metal reflector on bubble dynamics at the focus of an electrohydraulic lithotripter

Sapozhnikov, O.A., W. Kreider, M.R. Bailey, V.A. Khokhlova, and F. Curra, "Effect of elastic waves in the metal reflector on bubble dynamics at the focus of an electrohydraulic lithotripter," J. Acoust. Soc. Am., 123, 3367-3368, 2008.

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1 May 2008

In extracorporeal electrohydraulic lithotripters, a hemi-ellipsoidal metal reflector is used to focus a spherical wave generated by an electrical discharge. The spark source is positioned at one of the ellipsoid foci (F1); this makes the reflected wave focused at the other focus (F2). Despite the common assumption that the reflector behaves as a rigid mirror, the true reflection phenomenon includes the generation and reverberation of elastic waves in the reflector, which reradiate to the medium. Although these waves are much lower in amplitude than the specularly reflected wave, they may influence cavitation at F2. To explore such effects, waves in water and a brass reflector were modeled in finite differences based on the linearized equations of elasticity. The bubble response was simulated based on a Rayleigh-type equation for the bubble radius. In addition, the role of acoustic nonlinearity was estimated by numerical modeling. It is shown that the elastic waves in the reflector give rise to a long "ringing" tail, which results in nonmonotonic behavior of the bubble radius during its inertial growth after shock wave passage. This numerical result is qualitatively confirmed by experimental observations of bubble behavior using high-speed photography.

Therapeutic ultrasound: Surgery and drug delivery

Curra, F.P., and L.A. Crum, "Therapeutic ultrasound: Surgery and drug delivery," Acoust. Sci. Technol., 24, 343-348, doi:10.1250/ast.24.343, 2003.

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30 Jan 2003

The field of therapeutic ultrasound is emerging with strong potential and broad medical applications. Characterized by its ability to penetrate at depth inside the body without harming intervening tissue, ultrasound has posed the basis for a new array of noninvasive therapies. Al low intensities, important interactions occur in the tissue; wound healing is accelerated, functional recovery is enhanced, and bone growth is more rapid. At moderate intensities, cellular membranes show transient permeability, blood clots dissolution is increased, and gene-transfection is accomplished. At higher intensities, ultrasound produces lesions and stops bleeding by heating the tissue beyond its protein denaturalization threshold and thus provides a noninvasive, bloodless alternative to conventional surgery. This article presents a review of moderate and high intensity applications, including their mechanisms of action and the imaging modalities used for guidance and monitoring.

More Publications

Theoretical predictions and experimental results for non-invasive disease treatment via high intensity focused ultrasound: a comparative study

Curra, F.P., S.G. Kargl, C. Lafon, and L.A. Crum, "Theoretical predictions and experimental results for non-invasive disease treatment via high intensity focused ultrasound: a comparative study," Proceedings, Seventeenth International Congress on Acoustics, Rome Italy, 2-7 September (ICA, Rome, 2001).

2 Sep 2001

High-intensity focused ultrasound for noninvasive disease treatment: Theoretical predictions and experimental results

Curra, F.P., S.G. Kargl, C. Lafon, and L.A. Crum, "High-intensity focused ultrasound for noninvasive disease treatment: Theoretical predictions and experimental results," J. Acoust. Soc. Am., 109, 2457, 2001.

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1 May 2001

High-intensity focused ultrasound (HIFU) is becoming a widely accepted and "clean" modality to induce noninvasive coagulative necrosis of biological tissue for both cancer treatment and hemostasis. Theoretical predictions via the medusa (medical ultrasound algorithm) computer model of ultrasonic fields, temperature responses, and lesion dynamics are simulated for turkey breast. The model accounts for nonlinear sound propagation in inhomogeneous media, arbitrary frequency power law for acoustic attenuation, and temperature and lesion time histories. Generation of gas bubbles within the tissue may also be considered. Results are presented in terms of a comparison study with in vitro experiments on common turkey breast. Attention is mainly focused on temperature and lesion evolutions; in particular, induced lesion boundaries and collateral damage to surrounding areas.

Ultrasound accelerates functional recovery after peripheral nerve damage

Mourad, P.D., D.A. Lazar, F.P. Curra, B.C. Mohr, K.C. Andrus, A.M. Avellino, L.D. McNutt, L.A. Crum, and M. Kliot, "Ultrasound accelerates functional recovery after peripheral nerve damage," Neurosurgery, 48, 1140-1141, 2001.

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1 May 2001

Axonal injury in the peripheral nervous system is common, and often it is associated with severe long-term personal and societal costs. The objective of this study is to use an animal model to demonstrate that transcutaneous ultrasound can accelerate recovery from an axonotmetic injury.

The sciatic nerve of adult male Lewis rats was crushed in the right midthigh to cause complete distal degeneration of axons yet maintain continuity of the nerve. Beginning 3 days after surgery, various transcutaneous ultrasound treatments or sham treatments were applied 3 days per week for 30 days to the crush site of rats that were randomly assigned to two groups. In the preliminary experiments, there were three animals in each ultrasound group and two control animals. In the final experiment, there were 22 animals in the ultrasound group and 20 animals in the control group. Recovery was assessed by use of a toe spread assay to quantify a return to normal foot function in the injured leg. Equipment included a hand-held transducer that emitted continuous-wave ultrasound. The most successful ultrasound protocol had a spatial peak, time-averaged intensity of 0.25 W/cm2 operated at 2.25 MHz for 1 minute per application.

Rats subjected to the most successful ultrasound protocol showed a statistically significant acceleration of foot function recovery starting 14 days after injury versus 18 days for the control group. Full recovery by the ultrasound group occurred before full recovery by the control group.

Transcutaneous ultrasound applied to an animal model of axonotmetic injury accelerated recovery. Future studies should focus on identification of the mechanism(s) by which ultrasound creates this effect, as a prelude to optimization of the protocol, demonstration of its safety, and its eventual application to humans.

Acceleration of recovery after injury to the peripheral nervous system using ultrasound and other therapeutic modalities

Lazar, D.A., F.P. Curra, B. Mohr, D. McNutt, M. Kliot, and P.D. Mourad, "Acceleration of recovery after injury to the peripheral nervous system using ultrasound and other therapeutic modalities," Neurosurg. Clin. N. Am., 12, 353-357, 2001.

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1 Apr 2001

Taken together, these studies show the promise of various therapeutic modalities for the noninvasive treatment of peripheral nerve injury. Further progress on these promising methods requires determining the biologic mechanisms responsible for the ability of these modalities to enhance peripheral nerve recovery. Necessary investigations include validation or refutation of the hypothesis that these therapies act on various aspects of the natural healing process. Examples include cellular and molecular processes involved in promoting Wallerian degeneration and the rate and specificity of axonal regeneration and remyelination and muscle reinnervation, processes that are distributed between the regenerating nerve itself, the pathway of the regenerating axon, and the target of the regenerating nerve. An increased understanding of the biologic mechanisms underlying the enhancement of peripheral nerve recovery after injury would lend greater insight into the cellular and molecular mechanisms involved in successful nerve regeneration and muscle reinnervation. This increased understanding may also result in clinically beneficial treatments for peripheral nerve disorders.

Theoretical predictions of ultrasonic fields, temperature response, and lesion dynamics in biological tissue for the purpose of noninvasive disease treatment

Curra, F.P., P.D. Mourad, S.G. Kargl, L.A. Crum, and V.A. Khokhlova, "Theoretical predictions of ultrasonic fields, temperature response, and lesion dynamics in biological tissue for the purpose of noninvasive disease treatment," J. Acoust. Soc. Am., 108, 2546, 2000.

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1 Nov 2000

Ultrasound has been used for decades as a means for noninvasive treatment of diseases. Low-intensity ultrasound is routinely applied in physical therapy for muscular and neurological related illnesses. In contrast, high-intensity focused ultrasound (HIFU) is used to induce coagulative necrosis of tissue for cancer treatment or hemostasis. Our efforts concern the latter. Predictions of ultrasound fields, temperature response, and lesion dynamics are obtained by a model which accounts for nonlinear sound propagation in inhomogeneous media, an arbitrary frequency power law for acoustic attenuation, and temperature time history [J. Acoust. Soc. Am. 107, No. 5, Pt. 2 (2000)]. The model is expanded from its previous version to include attenuation and sound speed dependence on temperature levels and also to consider generation of gas bubbles within the tissue. Results are presented in terms of treatment strategies that provide maximum energy transfer for coagulating the targeted tissue while minimizing damage to the surrounding area.

Acoustic hemostasis

Crum, L.A., K. Beach, S. Carter, W. Chandler, F.P. Curra, P. Kaczkowski, G. Keilman, V. Khokhlova, R. Martin, P.D. Mourad, and S. Vaezy, "Acoustic hemostasis," in Nonlinear Acoustics at the Turn of the Millennium, edited by W. Lauterborn and T. Kurz, 13-22 (American Institute of Physics, New York, 2000).

1 Aug 2000

Numerical simulations of heating patterns and tissue temperature response due to high-intensity focused ultrasound fields

Curra, F.P., P.D. Mourad, V.A. Khokhlova, R.O. Cleveland, and L.A. Crum, "Numerical simulations of heating patterns and tissue temperature response due to high-intensity focused ultrasound fields," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 47, 1077-1088, 2000.

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1 Jul 2000

The results of this paper show—for an existing high intensity, focused ultrasound (HIFU) transducer—the importance of nonlinear effects on the space/time properties of wave propagation and heat generation in perfused liver models when a blood vessel also might be present. These simulations are based on the nonlinear parabolic equation for sound propagation and the bio-heat equation for temperature generation. The use of high initial pressure in HIFU transducers in combination with the physical characteristics of biological tissue induces shock formation during the propagation of a therapeutic ultrasound wave. The induced shock directly affects the rate at which heat is absorbed by tissue at the focus without significant influence on the magnitude and spatial distribution of the energy being delivered. When shocks form close to the focus, nonlinear enhancement of heating is confined in a small region around the focus and generates a higher localized thermal impact on the tissue than that predicted by linear theory. The presence of a blood vessel changes the spatial distribution of both the heating rate and temperature.

3D full wave ultrasonic field and temperature simulations in biological tissue containing a blood vessel

Curra, F.P., P.D. Mourad, L.A. Crum, and V.A. Khokhlova, "3D full wave ultrasonic field and temperature simulations in biological tissue containing a blood vessel," J. Acoust. Soc. Am., 107, 2814, doi:10.1121/1.429074, 2000.

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1 May 2000

In order to simulate ultrasound propagation and subsequent thermal effects in biological media in which blood vessels and other structures may be present, a three-dimensional model has been developed that eliminates the need for symmetry constraints. The model is based on the coupled solution of the full wave nonlinear equation of sound in a lossy medium and the bioheat equation obtained by a pseudospectral finite-difference method in the time domain. It includes nonlinear sound propagation, an arbitrary frequency power law for attenuation, and is capable of treating material inhomogeneities. Unlike other models based on parabolic approximations, it is not restricted to near-axis solutions and can account for reflections and backscattered fields. The program was used to simulate the application of high-intensity focused ultrasound (HIFU) in liver with a blood vessel placed perpendicular to the axis of the transducer and near the focus. This approach follows recent work by the authors [Curra et al., IEEE Trans. Ultrason. Ferroelectr., Freq. Control (in press)]. Simulations are presented for different levels of driving pressure, sound nonlinearities, exposure times, and the relative position between the transducer focus and the blood vessel.

Ultrasound accelerates the healing of damaged peripheral nerves in vivo

Mourad, P.D., F. Curra, L.A. Crum, D.A. Lazar, and M. Kliot, "Ultrasound accelerates the healing of damaged peripheral nerves in vivo," J. Acoust. Soc. Am., 107, 2815, 2000.

1 May 2000

Inventions

Multilayer Ultrasound Transducer Devices for High Power Transmission and Wide-band Reception and Associated Systems and Methods

Patent Number: 8,500,643

Francesco Curra, Peter Kaczkowski, Neil Owen

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Patent

6 Aug 2013

Multilayer ultrasound transducer devices for high power transmission and wide-band reception and associated methods and systems are disclosed herein. An ultrasound transducer device in accordance with an embodiment of the present technology, for example, can include a first array of first transducers and a second array of second transducers that are oriented substantially parallel to one another. The first transducers can include a first piezoelectric material that is configured to transmit acoustic waves, and the second transducers can include a second piezoelectric material that is configured to receive echoes from the acoustic waves. The ultrasound transducer device can further include an electrical connection layer between the first and second arrays that is electrically coupled to the first and second transducers.

Method and Apparatus for Ultrasound Dental Structure Scanning and Characterization

Record of Invention Number: 46462

John Kucewicz, Francesco Curra

Disclosure

30 Mar 2013

Acoustic Disruption and Deactivation of Biofilms in Catheters

Record of Invention Number: 45929

Yak-Nam Wang, Mike Bailey, Francesco Curra

Disclosure

15 Jan 2012

More Inventions

Method for Testing the Functionality of an Ultrasound Probe

Record of Invention Number: 45890

Peter Kaczkowski, John Kucewicz, Francesco Curra, Justin Reed

Disclosure

20 Dec 2011

Filtering Method for Supression of Non-stationary Reverberation in Ultrasound Images

Record of Invention Number: 45889

Francesco Curra, Justin Reed, John Kucewicz, Peter Kaczkowski

Disclosure

15 Dec 2011

Prevention of decompression illness by bubble growing and monitoring with a wearable, individualized device giving real-time recommendations

Record of Invention Number: 45470

Tom Matula, Francesco Curra, Alex Gu, Peter Tobias

Disclosure

1 Oct 2010

Ultrasound Method for Real-time Noninvasive Spatial Temperature Estimation

Record of Invention Number: 8646D

Francesco Curra, Neil Owen

Disclosure

8 Apr 2010

Multilayer Ultrasound Transducer for High-Power Transmission of Wideband Reception

Record of Invention Number: 8412D

Francesco Curra, Peter Kaczkowski, Neil Owen

Disclosure

7 Jul 2009

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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