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Publications

Search Publications by Stephen E. Russek

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Displaying 1 - 25 of 162

Characterization of 3-Dimensional Printing and Casting Materials for use in Computed Tomography and X-ray Imaging Phantoms

September 15, 2020
Author(s)
Bryan E. Yunker, Andrew Holmgren, Karl Stupic, J. L. Wagner, S Huddle, R Shandas, R. F. Weir, Katy Keenan, Edward Garboczi, Stephen E. Russek
Imaging phantoms are used to calibrate and validate the performance of medical computed tomography (CT) systems. Many new materials developed for three-dimensional (3D) printing processes may be useful in the direct printing or casting of biomimetic and

Characterization of 3-Dimensional Printing and Casting Materials for use in Magnetic Resonance Imaging Phantoms at 3 T

September 15, 2020
Author(s)
Bryan E. Yunker, Karl Stupic, J. L. Wagner, S Huddle, R Shandas, R. F. Weir, Stephen E. Russek, Katy Keenan
Imaging phantoms are used to calibrate and validate the performance of magnetic resonance imaging (MRI) systems. Many new materials have been developed for additive manufacturing (three-dimensional [3D] printing) processes that may be useful in the direct

Electromagnetics for Quantitative Magnetic Resonance Imaging

July 20, 2020
Author(s)
Stephen E. Russek, Karl F. Stupic, Joshua R. Biller, Michael A. Boss, Kathryn E. Keenan, Elizabeth Mirowski
Magnetic Resonance Imaging (MRI) is based on radio frequency (RF) interrogation of the human body at frequencies between 40 MHz to 300 MHz. An RF transmitter excites proton spin precession and then, in a manner analogous to an RF ID tag, the proton’s

Synaptic weighting in single flux quantum neuromorphic computing

January 22, 2020
Author(s)
Michael L. Schneider, Christine A. Donnelly, Ian W. Haygood, Alex Wynn, Stephen E. Russek, Manuel C. Castellanos Beltran, Paul D. Dresselhaus, Peter F. Hopkins, Matthew R. Pufall, William H. Rippard
Josephson junctions act as a natural spiking neuron-like device for neuromorphic computing. By leveraging the advances recently demonstrated in digital single flux quantum (SFQ) circuits and using recently demonstrated magnetic Josephson junction (MJJ)

Progress Towards Standards for Quantitative MRI (qMRI) and Outstanding Needs

January 24, 2019
Author(s)
Kathryn E. Keenan, Joshua R. Biller, Michael A. Boss, Adele P. Peskin, Karl F. Stupic, Stephen E. Russek, Jana Delfino, Mark Does, Jeffrey L. Evelhoch, Mark Griswold, Jeffrey Gunter, R Scott Hinks, Stuart Hoffman, Geena Kim, Riccardo Lattanzi, Xiaojuan Li, Luca Marinelli, Pratik Mukherjee, Robert J. Nordstrom, Elena Perez, Berkman Sahiner, Natalie J. Serkova, Amita Shukla-Dave, Michael Steckner, Lisa J. Wilmes, Holden Wu, Huiming Zhang, Edward F. Jackson, Daniel Sullivan
The National Institute of Standards and Technology (NIST) MRI Standards project held a one-day workshop on August 4, 2017 on campus in Boulder, CO. The goal of the workshop was to evaluate the advances in quantitative MRI (qMRI) since the last NIST

Energy efficient single flux quantum based neuromorphic computing

November 9, 2018
Author(s)
Michael L. Schneider, Christine A. Donnelly, Stephen E. Russek, Burm Baek, Matthew R. Pufall, Peter F. Hopkins, William H. Rippard
Many neuromorphic hardware technologies are being explored for their potential to increase the efficiency of computing certain problems, and thus facilitate machine learning with greater energy efficiency and or with more complexity. Among the technologies

High-speed low-power neuromorphic systems based on magnetic Josephson junctions

October 25, 2018
Author(s)
Michael Schneider, Christine A. Donnelly, Stephen E. Russek
Josephson junctions and single flux quantum (SFQ) circuits form a natural neuromorphic technology with SFQ pulses and superconducting transmission lines simulating action potentials and axons, respectively. Josephson junctions consist of superconducting

Nano-Sized Ferrite Particles for Magnetic Resonance Imaging Thermometry

September 8, 2018
Author(s)
Janusz H. Hankiewicz, J A. Stoll, John Stroud, J Davidson, K L. Livesey, K Tvrdy, Alexana Roshko, Stephen E. Russek, Karl Stupic, P Bilski, Robert E. Camley
Recently, we reported the use of magnetic particles as temperature indicators in magnetic resonance imaging thermometry (tMRI). In this method, the brightness of the MR image changes with temperature due to a temperature-dependent magnetic field

Large T1 contrast enhancement using superparamagnetic nanoparticles in ultra-low field MRI

June 5, 2018
Author(s)
Xiaolu Yin, Stephen E. Russek, Gary Zabow, Fan Sun, Jeotikanta Mohapatra, Kathryn E. Keenan, Michael A. Boss, Hao Zeng, Sy-Hwang Liou, John M. Moreland
Superparamagnetic iron oxide nanoparticles (SPIONs) are widely investigated and utilized as magnetic resonance imaging (MRI) contrast and therapy agents due to their large magnetic moments. Local field inhomogeneities caused by these high magnetic moments

Magnetic Resonance Imaging Biomarker Calibration Service: Proton Spin Relaxation Times

May 3, 2018
Author(s)
Michael A. Boss, Andrew M. Dienstfrey, Zydrunas Gimbutas, Kathryn E. Keenan, Jolene D. Splett, Karl F. Stupic, Stephen E. Russek
This document describes the calibration service to measure proton spin relaxation times, T1 and T2, of materials used in phantoms (calibration artifacts) to verify the accuracy of MRI-based quantitative measurements. Proton spin relaxation times are used

Ultralow power artificial synapses using nanotextured magnetic Josephson junctions

January 28, 2018
Author(s)
Michael L. Schneider, Christine A. Donnelly, Stephen E. Russek, Burm Baek, Matthew R. Pufall, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz, William H. Rippard
Neuromorphic computing is a promising avenue to dramatically improve the efficiency of certain computational tasks, such as perception and decision making. Neuromorphic systems are currently being developed for critical applications ranging from self

MRI Birdcage RF Coil Resonance with Uncertainty and Relative Error Convergence Rates

October 4, 2017
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Pedro V. Marcal, Robert Rainsberger, Karl F. Stupic, Stephen E. Russek
In a magnetic resonance imaging (MRI) system, it is necessary to excite the nuclei of a patient into coherent precession for imaging. This requires a coupling between the nuclei and a source of radio frequency (RF) power using a transmitter. To receive a

Quantitative Magnetic Resonance Imaging Phantoms: A Review and the Need for a System Phantom

October 4, 2017
Author(s)
Kathryn E. Keenan, Maureen Ainslie, Alexander J. Barker, Michael A. Boss, Kim M. Cecil, Cecil Charles, Thomas L. Chenevert, Laurence Clarke, Jeffrey L. Evelhoch, Paul Finn, Guoying Liu, Stephen E. Russek, Karl F. Stupic, Joshua D. Trzasko, Chun Yuan, Jie Zheng
The MRI community is using quantitative mapping techniques to complement qualitative imaging. For quantitative imaging to reach its full potential, it is necessary to analyze measurements across systems and longitudinally. Clinical use of quantitative

Accuracy, repeatability and interplatform reproducibility measurements of T 1 quantification methods used for DCE-MRI: results from a multicenter phantom study.

August 16, 2017
Author(s)
Octavia Bane, Stefanie J. Hectors, Mathilde Wagner, Lori L. Arlinghaus, Madhava P. Aryal, Yue Cao, Thomas L. Chenevert, Fiona Fennessy, Wei Huang, Nola M. Hylton, Jayashree Kalpathy-Cramer, Katy Keenan, Dariya I. Malyarenko, Robert V. Mulkern, David C. Newitt, Stephen E. Russek, Karl Stupic, Michael A. Boss
Purpose: To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. Methods: A T1 phantom with 14 samples was imaged at eight

Accuracy of magnetic resonance based susceptibility measurements

February 6, 2017
Author(s)
Hannah E. Erdevig, Stephen E. Russek, Slavka Carnicka, Karl F. Stupic, Kathryn E. Keenan
Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as

Stochastic Single Flux Quantum Neuromorphic Computing using Magnetically Tunable Josephson Junctions

October 17, 2016
Author(s)
Stephen E. Russek, Christine A. Donnelly, Michael L. Schneider, Burm Baek, Matthew R. Pufall, William H. Rippard, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
Abstract— Single flux quantum (SFQ) circuits form a natural neuromorphic technology with SFQ pulses and superconducting transmission lines simulating action potentials and axons, respectively. Here we present a new component, magnetic Josephson junctions

Comparison of T1 measurement using ISMRM/NIST system phantom

May 9, 2016
Author(s)
Kathryn E. Keenan, Karl F. Stupic, Michael A. Boss, Stephen E. Russek, Thomas L. Chenevert, Pottumarthi V. Prasad, Wilburn E. Reddick, Jie Zheng, Peng Hu, Edward F. Jackson
We used the ISMRM/NIST system phantom to assess variations of T1 measurements across MRI systems at 1.5 T and 3 T, to determine the repeatability and reproducibility of the T1 measurements. This study demonstrates that T1 variations from NMR-measured value

Variability and bias assessment in breast ADC measurement across multiple systems

February 29, 2016
Author(s)
Kathryn E. Keenan, Sheye O. Aliu, Lisa J. Wilmes, David C. Newitt, Ella F. Jones, Wen Li, Michael A. Boss, Karl F. Stupic, Stephen E. Russek, Nola M. Hylton
Purpose: To assess the ability of a recent, anatomically designed breast phantom incorporating T1 and diffusion elements to serve as a quality control device for quantitative comparison of apparent diffusion coefficient (ADC) measurements calculated from

Dynamics of Magnetic Nanoparticles and Nanodevices

May 31, 2015
Author(s)
Stephen E. Russek, Eric R. Evarts, Robert J. Usselman
Nanoscale magnetic devices and particles are being developed for a wide variety of applications including magnetic memory, nanoscale sensors, magnetic resonance imaging (MRI) agents, and therapeutic agents. Magnetic nanoparticles are also endogenous to the

On-wafer Magnetic Resonance of Magnetite Nanoparticles

May 11, 2015
Author(s)
Charles A. Little, Stephen E. Russek, James C. Booth, Pavel Kabos, Robert J. Usselman
Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nl) and a small numbers of spin (1 nmole). On

Terbium-Doped Magnetite Nanocrystals for Multimodal Imaging Agents

May 1, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin M. Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans T. Nembach, Elke Arenholz, Yves Idzerda
High quality cubic Tb-doped magnetite nanocrystals have been fabricated and have shown that the Tb is incorporated into the octahedral 3+ sites. Magnetization and FMR data indicate that the Tb spins are weakly coupled to the iron spin lattice at room

Nanoscale Spin Valve Josephson Junction Devices

April 14, 2015
Author(s)
Burm Baek, William H. Rippard, Matthew R. Pufall, Samuel P. Benz, Stephen E. Russek, Horst Rogalla, Paul D. Dresselhaus
Traditionally, superconductivity and magnetism have had a mutually exclusive relationship. However, the physics of superconductor-ferromagnet hybrid structures turned out to be far from being simply destructive, which has led to the hope of a new breed of

Temperature-dependent structure of Tb-doped magnetite nanoparticles

February 13, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin M. Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans T. Nembach, Elke Arenholz, Yves U. Idzerda
High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a modified wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the