These improvements to CW-EPR will allow changes of blood perfusion and oxygenation in tumors to be observed in nearly real-time, while improved resolution will permit angiogenesis in and around tumors to be carried out in a non-invasive manner.

Electron Paramagnetic Resonance (EPR) Imaging is an indispensable tool that may be applied to a variety of disciplines for evaluation of chemical species having unpaired electrons such as free radicals and transition metal ions.  In Continuous Wave (CW)-EPR the sample is continuously irradiated with weak RF radiation while sweeping the magnetic field relatively slowly.  Existing CW-EPR techniques utilize a signal detection method known as phase-sensitive detection which results in data acquisition times that are too long for in vivo applications.  The present technology represents significant improvements on conventional CW-EPR. 

The subject technology includes three approaches to collecting image data with increased spatial, temporal and spectral resolution and improved sensitivity.  Spectral data acquisition is performed by a direct detection strategy involving mixing a signal to base-band and acquiring data with a fast-digitizer.  Projection data is acquired using a sinusoidal magnetic field sweep under gradient magnetic fields.  Data collection times are decreased with the utility of rotating gradients.  Further, the current technology improves sensitivity by employing Digital Signal Processing, which decreases background analog noise.

Increased speed and sensitivity makes CW-EPR a potentially useful and complementary tool to Magnetic Resonance Imaging for in vivo imaging.  The presently described improvements to CW-EPR will allow changes of blood perfusion and oxygenation in tumors to be observed in nearly real-time, while improved resolution will permit angiogenesis in and around tumors to be carried out in a non-invasive manner.  Additionally, rapid scan imaging provides excellent temporal resolution and will help quantify pharmaco-kinetics and metabolic degradation kinetics of bioactive free radicals.

Applications:

·  Enhanced spatial, temporal, and spectral resolution of Continuous Wave-Electron Paramagnetic Resonance Imaging

·  Real-time assessment of changes in blood perfusion and oxygenation

Development Status: 

Preliminary experiments have been conducted and the technology has been tested for feasibility.

Publication:

S Subramanian, JW Koscielniak, N Devasahayam, RH Pursley,  TJ Pohida, TJ Pohida, MC Krishna. A new strategy for fast radiofrequency CW EPR imaging: direct detection with rapid scan and rotating gradients.  J Magn Reson. 2007 Jun;186(2):212-219. [PubMed abs]

Patent Status: 

U.S. Provisional Application No. 60/818,052 filed 30 Jun 2006 (HHS Reference No. E-221-2005/0-US-01)

PCT Application No. PCT/US2007/00072371 filed 02 Jul 2007 (HHS Reference No. E-221-12005/0-PCT-02)

 

Inventors: 

Sankaran Subramanian, Nallathamby Devasahayam, Janusz Koscielniak, James Mitchell, and Murali Krishna (NCI)

 

Licensees Sought: 

Available for non-exclusive or exclusive licensing and commercial development.

Collaborative Research Opportunity: 

The Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize the above Rapid scan-Rotating gradients strategy for performing routine in vivo Radiofrequency CW EPR imaging in small animals.  Please contact John D. Hewes, Ph.D. at 301-435-3121 or hewesj@mail.nih.gov for more information.