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Technology Transfer Center of the National Cancer Institute

Fast Electron Paramagnetic Resonance Imaging (EPRI) for Cancer Research and Diagnostics

Keywords:  Diagnostics, Diagnostic Imaging, Spectrometer, Electron Paramagnetic Resonance Imaging, EPRI

Background:
The National Cancer Institute, Radiation Biology Branch is seeking statements of capability or interest from parties interested in collaborative research to further improve the hardware in terms of higher gradient & sweep frequencies and compatible AC amplifiers and evaluate or commercialize the above rapid scan-rotating gradients strategy for performing routine in vivo radiofrequency CW EPR imaging in small animals.

Description of Invention: 
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 improvement to the present technology includes optimized DSP (digital signal processing) transmit and receive systems that decrease  the analog background noise and  allow optimizing the extent of signal averaging for improved image quality.

Advantages:

  • Increased speed and sensitivity make CW-EPR a potentially useful and complementary tool to proton Magnetic Resonance Imaging for in vivo imaging.
  • Allows 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  monitored in a non-invasive manner;
  • Rapid scan imaging provides excellent temporal resolution and will help quantify pharmaco-kinetics and metabolic degradation kinetics of bioactive and redox sensitive free radicals such as nitroxides.
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:  Lab-scale prototype

Relevant Publication: 
Subramanian S, Koscielniak JW, Devasahayam N, Pursley RH, Pohida TJ, Krishna MC. 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: 17350865]

Patent Status:
  • U.S. Provisional Application No. 60/818,052 filed 30 Jun 2006; PCT Application No. PCT/US07/00072371 filed 02 Jul 2007, which published as WO 2008/091365 on 31 Jul 2008; U.S. Patent Application No. 12/306,514 filed 23 Dec 2008; U.S. Patent Application No. 12/564,006 filed 21 Sep 2009.

Contact Information:
John D. Hewes, Ph.D.
301-435-3121
hewesj@mail.nih.gov
http://ttc.nci.nih.gov

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