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Brian MacConaghy

Physicist IV






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

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


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


2000-present and while at APL-UW

Simulation of laser lithotripsy-induced heating in the urinary tract

Maxwell, A.D., B. MacConaghy, J.D. Harper, A.H. Aldoukhi, T.L. Hall, and W.W. Roberts, "Simulation of laser lithotripsy-induced heating in the urinary tract," J. Endourol., 33, doi:10.1089/end.2018.0485, 2019.

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15 Feb 2019

Purpose: Holmium laser lithotripsy is a common modality used to fragment urinary stones during ureteroscopy. Laser energy deposited during activation produces heat and potentially causes thermal bioeffects. We aimed to characterize laser-induced heating through a computational simulation.

Materials and Methods: A finite-element model was developed and used to estimate temperature in the urinary tract. Axisymmetric models of laser lithotripsy in a renal calyx, the renal pelvis, and proximal ureter were created. Heat generation by laser and heat transfer were simulated under different laser powers between 5 and 40 W. Irrigation fluid flow was introduced at rates between 0 and 40 mL/min. The model was validated by comparison with previous in vitro temperature data in a test tube, then used to calculate heating and thermal dose in the three tissue models.

Results: Simulated temperature rises agreed well with most in vitro experimental measurements. In tissue models, temperature rises depended strongly on laser power and irrigation rate, and to a lesser extent on location. Injurious temperatures were reached for 5–40 W laser power without irrigation, >10 W with 5 mL/min irrigation, 40 W with 15 mL/min irrigation, and were not found at 40 mL/min irrigation. Tissue injury volumes up to 2.3 cm3 were calculated from thermal dose.

Conclusions: The results suggest a numerical model can accurately simulate the thermal profile of laser lithotripsy. Laser heating is strongly dependent on parameters and may cause a substantial temperature rise in the fluid in the urinary tract and surrounding tissue under clinically relevant conditions.

Inactivation of planktonic Escherichia coli by focused 1-MHz ultrasound pulses with shocks: Efficacy and kinetics upon volume scale-up

Brayman, A.A., B.E. MacConaghy, Y.-N. Wang, K.T. Chan, W.L. Monsky, V.P. Chernikov, S.V. Buravkov, V.A. Khokhlova, and T.J. Matula, "Inactivation of planktonic Escherichia coli by focused 1-MHz ultrasound pulses with shocks: Efficacy and kinetics upon volume scale-up," Ultrasound Med. Biol., 44, 1996-2008, doi:10.1016/j.ultrasmedbio.2018.05.010, 2018.

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1 Sep 2018

This study addresses inactivation of E. coli in either 5- or 10-mL volumes, which were 50- to 100-fold greater than used in an earlier study (Brayman et al. 2017). Cells were treated with 1-MHz pulsed high-intensity focused ultrasound (10 cycles, 2-kHz repetition frequency, +65/–12.8 MPa focal pressures). The surviving fraction was assessed by coliform assay, and inactivation demonstrated curvilinear kinetics. The reduction of surviving fraction to 50% required 2.5 or 6 min in 5- or 10-mL samples, respectively. Exposure of 5 mL for 20 min reduced the surviving fraction to ~1%; a similar exposure of 10-mL samples reduced the surviving fraction to ~10%. Surviving cells from 5-min exposures appeared normal under light microscopy, with minimal debris; after 20 min, debris dominated. Transmission electron microscopy images of insonated samples showed some undamaged cells, a few damaged but largely intact cells and comminuted debris. Cellular damage associated with substantive but incomplete levels of inactivation can be variable, ranging from membrane holes tens of nanometers in diameter to nearly complete comminution.

Caliceal fluid temperature during high-power holmium laser lithotripsy in an in vivo porcine model

Aldoukhi, A.H., T.L. Hall, K.R. Ghani, A.D. Maxwell, B. MacConaghy, and W.W. Roberts, "Caliceal fluid temperature during high-power holmium laser lithotripsy in an in vivo porcine model," J. Endourol., 32, 724-729, doi:10.1089/end.2018.0395, 2018.

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1 Aug 2018

With increasing use of high-power laser settings for lithotripsy, the potential exists to induce thermal tissue damage. In vitro studies have demonstrated that temperature elevation sufficient to cause thermal tissue damage can occur with certain laser and irrigation settings. The objective of this pilot study was to measure caliceal fluid temperature during high-power laser lithotripsy in an in vivo porcine model.

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Ultrasound Stylet

Patent Number: 10,123,766

Pierre Mourad, Samuel R. Browd, Brian MacConaghy, Revathi Murthy, Nathaniel Coulson

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13 Nov 2018

A stylet (100) includes a handle assembly (102) with an indicator display (112) and a stiff wire assembly (120) extending distally from the handle assembly (102) having a non-imaging ultrasonic device on a distal end. The stylet includes a circuit assembly having one or more of a pulser (120), a transmit/receive chip (132), a bandpass filter (134), a differential amplifier (136), an ADC (138), and an MCU (140), operable to control the operation of the ultrasonic device and to receive and analyze data from the ultrasonic device to facilitate implantation of a device such as a catheter.

Time-reversal based ultrasound system for processing biological samples

Record of Invention Number: 48375

Brian MacConaghy, Adam Maxwell


10 Jul 2018

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

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.

Patent Number: 9,645,080

Tom Matula, Andrew Brayman, Oleg Sapozhnikov, Brian MacConaghy, Jarred Swalwell, Camilo Perez


9 May 2017

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