APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

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

More Info

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

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.

More Info

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.

Defining thermally safe laser lithotripsy power and irrigation parameters: In vitro model

Aldoukhi, A.H., K.M. Black, T.L. Hall, K.R. Ghani, A.D. Maxwell, B. MacConaghy, and W.W. Roberts, "Defining thermally safe laser lithotripsy power and irrigation parameters: In vitro model," J. Endourol., 34, 76-81, doi:10.1089/end.2019.0499, 2020.

More Info

16 Jan 2020

High-power laser settings are commonly employed for stone dusting techniques. Previous in vitro and in vivo studies have demonstrated that a toxic thermal dose can result from treatment within a renal calix without adequate irrigation. Hence, both laser power and irrigation rate must be considered together to determine safe laser lithotripsy parameters. The objective of this in vitro study was to map parameter safety boundaries and create guidelines for selection of safe laser and irrigation settings.

The experimental system consisted of in vitro models simulating ureter, renal calix, and renal pelvis placed in a water bath maintained at 37°C. Temperature was recorded during ureteroscopy with laser activation for 60 seconds. Trials were conducted at strategically selected power levels and irrigation rates. Thermal dose for each trial was calculated based on Sapareto and Dewey t43 methodology with thermal dose >120 equivalent minutes considered to result in thermal tissue injury. A parameter safety boundary was established by plotting the maximal safe power level for each irrigation rate.

The parameter safety boundary was found to be linear for each scenario with the renal pelvis able to tolerate the highest laser power and the renal calix the least power without injury.

This study describes the methodology to determine parameter safety boundaries that can be used to guide proper selection of thermally safe laser settings and irrigation rates during ureteroscopy with laser lithotripsy. This work provides a framework to assess the effectiveness of various strategies to control and mitigate thermal dose.

PIXUL-ChIP: Integrated high-throughput sample preparation and analytical platform for epigenetic studies

Bomsztyk, K., D. Mar, Y. Wang, O. Denisenko, C. Ware, C.D. Frazar, A. Blattler, A.D. Maxwell, B.E. MacConaghy, and T.J. Matula, "PIXUL-ChIP: Integrated high-throughput sample preparation and analytical platform for epigenetic studies," Nucleic Acids Res., 47, doi:10.1093/nar/gkz222, 2019.

More Info

30 Mar 2019

Chromatin immunoprecipitation (ChIP) is the most widely used approach for identification of genome-associated proteins and their modifications. We have previously introduced a microplate-based ChIP platform, Matrix ChIP, where the entire ChIP procedure is done on the same plate without sample transfers. Compared to conventional ChIP protocols, the Matrix ChIP assay is faster and has increased throughput. However, even with microplate ChIP assays, sample preparation and chromatin fragmentation (which is required to map genomic locations) remains a major bottleneck. We have developed a novel technology (termed 'PIXUL') utilizing an array of ultrasound transducers for simultaneous shearing of samples in standard 96-well microplates. We integrated PIXUL with Matrix ChIP ('PIXUL-ChIP'), that allows for fast, reproducible, low-cost and high-throughput sample preparation and ChIP analysis of 96 samples (cell culture or tissues) in one day. Further, we demonstrated that chromatin prepared using PIXUL can be used in an existing ChIP-seq workflow. Thus, the high-throughput capacity of PIXUL-ChIP provides the means to carry out ChIP-qPCR or ChIP-seq experiments involving dozens of samples. Given the complexity of epigenetic processes, the use of PIXUL-ChIP will advance our understanding of these processes in health and disease, as well as facilitate screening of epigenetic drugs.

More Publications

Inventions

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

Ultrasound Stylet

Patent Number: 10,123,766

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

More Info

Patent

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

Disclosure

10 Jul 2018

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
Close

 

Close