Electron Paramagnetic Resonance Image Reconstruction Activity

Brief Description

Electron Paramagnetic Resonance (EPR) is a spectroscopic technique that detects and characterizes molecules with unpaired electrons (i.e., free radicals).  Although it is closely related to nuclear magnetic resonance (NMR) spectroscopy, EPR is still under development as an imaging modality.  Unlike other imaging modalities, EPR is able to take direct measurements of tissue oxygen concentration in a manner that is not dependent on complex biological processes such as ligand binding specificity or tracer metabolism.  The single-point imaging (SPI) scheme is essentially a phase-encoding technique that operates by acquiring a single data point in the free induction decay (FID) after a fixed delay (the phase encoding time), in the presence of static magnetic field gradients.  SPI produces artifact-free images because it does not measure the time evolution of the magnetization.   The goal of this project is to provide computational methodology and resources that will advance the state of the science in EPR.  A particular focus of this collaboration is the development of reconstruction methodology that will improve the quality of oximetric images obtained using the SPI technique.

List of Collaborators

• Murali Krishna Cherukuri, Ph.D., Radiation Biology Branch, NCI
• James Mitchell, M.D., Ph.D., Radiation Biology Branch, NCI
• Sankaran Subramanian, Ph.D., Radiation Biology Branch, NCI
• John Cook, Ph.D., Radiation Biology Branch, NCI
• Nallathamby Devashayam, Radiation Biology Branch, NCI
• Christopher Dharmaraj, Radiation Biology Branch, NCI

Major Accomplishments in FY 2007

HPCIO installed a 4 dual-core CPU Linux server in the Radiation Biology Branch to process the raw SPI image data into the final oximetric images.  HPCIO also worked with NCI staff to configure the application to automatically pre-process the raw data.  This deployment necessitated modifying the existing MATLAB program to incorporate the MATLAB Distributed Computing Toolbox to allow for parallel processing of the data.  Overall these changes have allowed NCI to process data in the order of a minute on their own equipment rather than the 35 minutes or so required previously.

Anticipated Major Accomplishments in FY 2008

HPCIO expects to continue supporting NCI with this project throughout the coming year,  Part of this support is likely to be training the NCI staff to take over full development, maintenance and administration roles.

 Publications

S. Subramanian, C.A. Johnson, N. Devasahayam, K. Matsumoto, F. Hyodo, J. Cook, and M.C. Krishna, “In vivo Spectral-Spatial Imaging for Oxygen Mapping Using Single-Point, Time-Domain Electron Paramagnetic Resonance,” Proceedings of Cambridge Healthtech Institute’s Second Annual Conference on In Vivo Molecular Imaging, San Diego, CA, IMG536, 2005.

S. Subramanian, C.A. Johnson, N. Devasahayam, K. Matsumoto, F. Hyodo, J. Cook, and M.C. Krishna, “In vivo Spectral-Spatial Imaging for Oxygen Mapping Using Single-Point, Time-Domain Electron Paramagnetic Resonance,” Proceedings of the 2006 IEEE International Symposium On Biomedical Imaging, Crystal City, VA (2006), SA-PM-OS4.1.  

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