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Ethan K. Murphy

Assistant Professor of Engineering

+1 (603) 650-1931

ethan.k.murphy@dartmouth.edu

LinkedIn

Electrical Impedance Imaging and Modeling for Neurological Applications: Stroke and tDCS

Related Links

Halter Lab

Github page

Overview

My research primarily involves physics-based electrical modeling, imaging electrical properties with a technique called electrical impedance tomography (EIT), and using a combination of computational techniques to improve these methods for practical biomedical applications. Much of my work involves 3D mesh generation for finite element method problems and fusing data from multiple data sources.

Research Interests

Electrical impedance tomography; data fusion; finite element method (FEM) modeling; noise/data filtering; general numerical methods; magnetic resonance electrical property tomography; electroencephalogram (EEG) source localization

Education

  • BS, Mathematics, Worcester Polytechnic Institute 2002
  • MS, Industrial Mathematics, Worcester Polytechnic Institute 2002
  • PhD, Mathematics, Colorado State University 2007

Awards

  • Society of Critical Care Medicine’s Gold Snapshot Award, 2021
  • Clinical Poster Award, Northeast Amyotrophic Lateral Sclerosis Conference, 2019
  • Best Creative Work, Saratov State Technical University, 2010

Research Projects

  • Electrical impedance tomography in pulmonary and cardiac applications

    Electrical impedance tomography in pulmonary and cardiac applications

    The most common application, so far, of electrical impedance tomography (EIT) has been pulmonary monitoring of patients. In particular, we have been pursuing EIT for cardiac output monitoring (a related application) and EIT as a surrogate for pulmonary function tests.

  • Combined whole breast ultrasound and electrical impedance tomography

    Combined whole breast ultrasound and electrical impedance tomography

    Ultrasound is a supplemental screening technique that has good sensitivity in dense breasts, is inexpensive, and is widely available, but unfortunately, it has high rates of false positives. Electrical impedance tomography (EIT) is a second attractive modality that is low-cost and has shown promise for cancer detection and in differentiating fibrocystic tissues from other tissues. Combining automated whole breast ultrasound (ABUS), which is a recent improvement to standard ultrasound, with EIT may significantly reduce the number of false positives of ABUS. If successful, the combined ABUS/EIT system could become an important screening technology for women with dense breasts.

  • Imaging muscle properties with combined ultrasound and electrical impedance tomography

    Imaging muscle properties with combined ultrasound and electrical impedance tomography

    Assessing muscle health is important diagnostic information in the treatment of numerous peripheral nerve diseases. This project aims to incorporate spatial information from ultrasound into the inverse problem of electrical impedance tomography in order to accurately image the electrical properties of the muscle (under the skin and adipose tissue).

  • Electrical impedance imaging for prostate cancer screening

    Electrical impedance imaging for prostate cancer screening

    Electrical impedance imaging for prostate cancer screening is the process of imaging non-invasively the electrical properties (conductivity and permittivity) of the prostate and its vicinity using electrodes mounted onto an intracavitary probe.

Selected Publications

  • E.K. Murphy, S.R. Bertsch, S.B. Klein, N. Rashedi, Y. Sun, M.J. Joyner, T.B. Curry, C.P. Johnson, R.J. Regimbal, C.C. Wiggins, and J.W. Senefeld, 2024. Non-invasive biomarkers for detecting progression toward hypovolemic cardiovascular instability in a lower body negative pressure model. Scientific Reports, 14(1), p.8719. doi: 10.1038/s41598-024-59139-8.
  • A. Everitt, H. Richards, Y. Song, J. Smith, E. Kobylarz, T. Lukovits, R. Halter, and E. Murphy, 2023. EEG electrode localization with 3D iPhone scanning using point-cloud electrode selection (PC-ES). Journal of Neural Engineering, 20(6), p.066033. doi: 10.1088/1741-2552/ad12db.
  • E.K. Murphy, J. Smith, M.A. Kokko, S.B. Rutkove, and R.J. Halter, 2024. Rapid patient-specific FEM meshes from 3D smart-phone based scans. Physiological Measurement, 45(2), p.025008. doi: 10.1088/1361-6579/ad26d2.
  • E.K. Murphy, X. Wu, A. Everitt, and R.J. Halter, "Phantom Studies of Fused-data TREIT using only Biopsy-probe electrodes," IEEE Trans. Med. Imag., 2020 (accepted).
  • E.K. Murphy, J. Skinner, M. Martucci, S.B. Rutkove, and R.J. Halter, "Toward Electrical Impedance Tomography Coupled Ultrasound Imaging for Assessing Muscle Health," IEEE Transactions on Medical Imaging, vol. 38, no. 6, pp.1409–1419, 2018.
  • E.K. Murphy, X. Wu, and R.J. Halter, "Fused-data Transrectal EIT for Prostate Cancer Imaging," Physiological Measurement, vol. 39, no. 5, p.054005, 2018.
  • E.K. Murphy, A. Mahara, X. Wu, and R.J. Halter, "Phantom Experiments using Soft-Prior Regularization EIT for Breast Cancer Imaging," Physiological Measurement, vol. 38, no. 6, pp.1262–1277, 2017.
  • E.K. Murphy, A. Mahara, S. Khan, E.S. Hyams, A.R. Schned, J. Pettus, and R.J. Halter, "Comparative Study of Separation between ex vivo Prostatic Malignant and Benign Tissue using Electrical Impedance Spectroscopy and Electrical Impedance Tomography," Physiological Measurement, vol. 38, no. 6, pp.1242–1261, 2017.
  • E.K. Murphy, A. Mahara, and R.J. Halter, "Absolute Reconstructions using Rotational Electrical Impedance Tomography for Breast Cancer Imaging," IEEE Trans. on Med. Img., vol. 36, no. 4, pp.892–903, 2017.
  • E.K. Murphy, A. Mahara, and R.J. Halter, "A Novel Regularization Technique for Microendoscopic Electrical Impedance Tomography," IEEE Trans. Med. Imaging, vol. 35, no. 7, pp. 1593–1603, 2016.
  • V. Brovko, E.K. Murphy, and V.V. Yakovlev, "Waveguide Microwave Imaging: Solids Volume Fraction of Particulate Materials," Appl. Comput. Electromagn. Soc. J., vol. 30, no. 11, pp. 1161–1167, 2015.
  • E.K. Murphy and V.V. Yakovlev, "Neural Network Optimization of Complex Microwave Structures with a Reduced Number of Full-Wave Analyses," International Journal of RF & Microwave Computer-Aided Engineering, vol. 21, no. 2, pp. 279–287, 2011.
  • E.K. Murphy and J.L. Mueller, "Effect of Domain Shape Modeling and Measurement Errors on the 2-D D-bar Method for EIT," IEEE Trans. on Medical Imaging, vol. 28, pp. 1576–1584, 2009.

Videos

Electrical Impedance Imaging and Modeling for Neurological Applications: Stroke and tDCS

News

Welcome: New Faculty
Mar 15, 2021
Joint Dartmouth-Hitchcock and Dartmouth Team Wins Society of Critical Care Medicine Award
Dec 16, 2020
Dartmouth Awarded NIH Grant for Device to Detect Cancer Left Behind During Surgery
Aug 25, 2020

Research Quick Takes

Navid Rashedi

Feb 27, 2025

Early Detection of Internal Bleeding

PhD student Navid Rashedi (pictured), Professor Ethan Murphy, Alexandra Hamlin '16 Th'17 Th'19, research associate Victor Borza, and Professors Jonathan Elliott, Ryan Halter, and Vikrant Vaze are co-authors of: "Detection of occult hemorrhage using multivariate non-invasive technologies" published in Physiological Measurement. "This work investigated machine learning to combine multiple technologies—electrical impedance and near infrared spectroscopy—to better detect internal bleeds in a porcine study. Internal bleeds are often not detectable until it's too late. This approach appears to detect them earlier and more accurately," said Murphy. 

LBNP experiment set-up

May 02, 2024

EIT for Early Bleed Detection

PhD students Spencer Bertsch Th'19 and Navid Rashedi, alum Yifei Sun Th'22, and Professors Ethan Murphy (first author), Jonathan Elliott, Ryan Halter, and Vikrant Vaze—along with DHMC and Mayo Clinic researchers—co-authored "Non-invasive biomarkers for detecting progression toward hypovolemic cardiovascular instability in a lower body negative pressure model" published in Scientific Reports. The paper summarizes how electrical impedance tomography (EIT) can be used as a novel marker for early bleed detection.

ENDO GIA stapler

Jan 11, 2024

A Better, Safer Surgical Stapler

Professors Ethan Murphy and Ryan Halter, and PhD student Harsha Devaraj, along with Medtronic collaborators, coauthored "Development of an Electrical Impedance Tomography Coupled Surgical Stapler for Tissue Characterization" published in IEEE Transactions on Biomedical Engineering. The featured article investigates the incorporation of electrical impedance tomography into a surgical stapler to improve outcomes. Further studies are planned based on the promising results.

Using an iPhone to produce accurate high-density EEG scans for electrode localization

Dec 14, 2023

3D iPhone Scanning for EEG

Alums Alicia Everitt Th'19 and Haley Richards Th'22 are first authors on "EEG electrode localization with 3D iPhone scanning using point-cloud electrode selection" accepted for publication by the Journal of Neural Engineering. The authors, including Professors Ryan Halter and Ethan Murphy, present a method "using an iPhone to produce accurate high-density EEG scans for electrode localization—providing a needed portable and inexpensive solution," says Murphy.