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Brian MacConaghy

Physicist IV

Email

brianm@apl.washington.edu

Phone

206-897-1869

Education

B.S. Physics, University of Washington - Seattle, 2004

M.S. Applied Mathematics, University of Washington - Seattle, 2006

Videos

PIXUL: PIXelated ULtrasound Speeds Disease Biomarker Search

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26 Apr 2018

Accurate assessment of chromatin modifications can be used to improve detection and treatment of various diseases. Further, accurate assessment of chromatin modifications can have an important role in designing new drug therapies. This novel technology applies miniature ultrasound transducers to shear chromatin in standard 96-well microplates. PIXUL saves researchers hours of sample preparation time and reduces sample degradation.

Non-invasive Treatment of Abscesses with Ultrasound

Abscesses are walled-off collections of fluid and bacteria within the body. They are common complications of surgery, trauma, and systemic infections. Typical treatment is the surgical placement of a drainage catheter to drain the abscess fluid over several days. Dr. Keith Chan and researchers at APL-UW's Center for Industrial + Medical Ultrasound are exploring how to treat abscesses non-invasively, that is, from outside the body, with high-intensity focused ultrasound (HIFU). This experimental therapy could reduce pain, radiation exposure, antibiotic use, and costs for patients with abscesses. Therapeutic ultrasound could also treat abscesses too small or inaccessible for conventional drainage.

20 Jun 2016

Flow Cytometry Techniques Advance Microbubble Science

Researchers at the Center for Industrial and Medical Ultrasound (CIMU) are measuring the physical properties of ultrasound contrast agents — tiny gas bubbles several microns in diameter used to increase sonogram imaging efficiency in the body. When injected to the general circulation they can act as probes and beacons within the body, and can carry and deploy chemotherapeutic payloads.

CIMU researchers have developed a hybrid instrument that combines an off-the-shelf flow cytometer with an acoustic transducer. The cytometer's laser interrogation counts and measures the bubbles while the acoustic interrogation reveals the bubbles' viscosity and elasticity at megahertz frequencies.

5 Dec 2013

Publications

2000-present and while at APL-UW

A simulated model for fluid and tissue heating during pediatric laser lithotripsy

Ellison, J.S., B. MacConaghy, T.L. Hall, W.W. Roberts, A.D. Maxwell, "A simulated model for fluid and tissue heating during pediatric laser lithotripsy," J. Pediatr. Urol., 16, doi:10.1016/j.jpurol.2020.07.014, 2020.

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1 Oct 2020

Laser lithotripsy (LL) is a common modality for treatment of children and adolescents with nephrolithiasis. Recent introduction of higher-powered lasers may result in more efficacious "dusting" of urinary calculi. However, in vivo animal studies and computational simulations have demonstrated rapid and sustained rise of fluid temperatures with LL, possibly resulting in irreversible tissue damage. How fluid and tissue heating during LL vary with pediatric urinary tract development, however, is unknown. We hypothesize that kidneys of younger children will be more susceptible to changes in fluid temperature and therefore tissue damage than those of older children. Smaller renal size is more susceptible to thermal changes induced by LL. However, power settings equal to or greater than 20 W can result in temperatures high enough for tissue damage at any age. Continuous pressure flow and intermittent laser activity may mitigate the potential thermal damage from high power LL.

Histotripsy treatment of abscesses

Matula, T.J., Y.-N. Wang, T. Khokhlova, D.F. Leotta, J. Kucewicz, A.A. Brayman, M. Bruce, A.D. Maxwell, B.E. MacConaghy, G. Thomas, K. Richmond, K. Chan, and W. Monsky, "Histotripsy treatment of abscesses," in Proc., IEEE International Ultrasonics Symposium, 7-11 September, Las Vegas, NV, doi:10.1109/IUS46767.2020.9251683 (IEEE, 2020).

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7 Sep 2020

Abscesses are walled-off collections of infected fluids containing pus and bacteria. They are often treated with percutaneous drainage in which a drainage catheter may be sutured in place for up to several weeks. Complications such as clogged drains or secondary infections require rehospitalization and wound management. Bacteria are susceptible to mechanical damage, and thus we hypothesize that histotripsy may be a potential new paradigm for treating abscesses noninvasively, without the need for long term catheterization and antibiotics. We developed a porcine animal model that recapitulates some of the features of human abscesses (including size and loculations). Boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses in this porcine model. Ultrasound imaging was used to evaluate abscess maturity, for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

An investigation of elastic waves producing stone fracture in burst wave lithotripsy

Maxwell, A.D., B. MacConaghy, M.R. Bailey, and O.A. Sapozhnikov, "An investigation of elastic waves producing stone fracture in burst wave lithotripsy," J. Acoust. Soc. Am., 147, 1607-1622, doi:10.1121/10.0000847, 2020.

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1 Mar 2020

Burst wave lithotripsy is a method to noninvasively fragment urinary stones by short pulses of focused ultrasound. In this study, physical mechanisms of stone fracture during burst wave lithotripsy were investigated. Photoelasticity imaging was used to visualize elastic wave propagation in model stones and compare results to numerical calculations. Epoxy and glass stone models were made into rectangular, cylindrical, or irregular geometries and exposed in a degassed water bath to focused ultrasound bursts at different frequencies. A high-speed camera was used to record images of the stone during exposure through a circular polariscope backlit by a monochromatic flash source. Imaging showed the development of periodic stresses in the stone body with a pattern dependent on frequency. These patterns were identified as guided wave modes in cylinders and plates, which formed standing waves upon reflection from the distal surfaces of the stone model, producing specific locations of stress concentration in the models. Measured phase velocities compared favorably to numerically calculated modes dependent on frequency and material. Artificial stones exposed to bursts produced cracks at positions anticipated by this mechanism. These results support guided wave generation and reflection as a mechanism of stone fracture in burst wave lithotripsy.

More Publications

Inventions

Ultrasound System for Shearing Cellular Material in a Microplate

Patent Number: 10,809,166

Tom Matula, Brian MacConaghy, Adam Maxwell

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Patent

20 Oct 2020

Disclosed embodiments include illustrative piezoelectric element array assemblies, methods of fabricating a piezoelectric element array assembly, and systems and methods for shearing cellular material. Given by way of non-limiting example, an illustrative piezoelectric element array assembly includes at least one piezoelectric element configured to produce ultrasound energy responsive to amplified driving pulses. A lens layer is bonded to the at least one piezoelectric element. The lens layer has a plurality of lenses formed therein that are configured to focus ultrasound energy created by single ones of the at least one piezoelectric element into a plurality of wells of a microplate disposable in ultrasonic communication with the lens layer, wherein more than one of the plurality of lenses overlie single ones of the at least one piezoelectric element.

Methods for Separating, Concentrating, and/or Differentiating Between Cells from a Cell Sample

Patent Number: 10,794,827

Tom Matula, Oleg Sapozhnikov, Brian MacConaghy

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Patent

6 Oct 2020

Embodiments are generally related to differentiating and/or separating portions of a sample that are of interest from the remainder of the sample. Embodiments may be directed towards separating cells of interest from a cell sample. In some embodiments, acoustic impedances of the cells of interest may be modified. For example, the acoustic properties of the cells of interest may be modified by attaching bubbles to the cells of interest. The cell sample may then be subjected to an acoustic wave. The cells of interest may be differentiated and/or separated from the remainder of the sample based on relative displacements and/or volumetric changes experienced by the cells of interest in response thereto. The cells of interest may be separated using a standing wave and sorted into separate channels of a flow cell. Optionally, the cells may be interrogated by a light source and differentiated by signals generated in response thereto.

Device and Method to Break Urinary Stones in Pets

Record of Invention Number: 48640

Mike Bailey, Dan Leotta, Elizabeth Lynch, Brian MacConaghy, Adam Maxwell

Disclosure

28 May 2019

More Inventions

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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