Fast Electron Paramagnetic Resonance Imaging (EPRI) for Cancer Research and Diagnostics
Keywords: Diagnostics, Diagnostic Imaging, Spectrometer,
Electron Paramagnetic Resonance Imaging, EPRI
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
- 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
- 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
- Enhanced spatial, temporal, and spectral resolution of
Continuous Wave-Electron Paramagnetic Resonance Imaging
- Real-time assessment of changes in blood perfusion and
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]
- 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.
John D. Hewes, Ph.D.
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