title: Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo.
abstract: We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH•, NO•). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 µT (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.
authors: Department of Chemistry and Biochemistry, University of Denver; Magnetic Imaging Group, Applied Physics Division, Physical Measurements Laboratory, National Institute of Standards and Technology.
authors: Joshua R
authors: JR
authors: Biller
authors: Department of Chemistry and Biochemistry, University of Denver.
authors: Deborah G
authors: DG
authors: Mitchell
authors: Department of Radiology, Geisel School of Medicine, Dartmouth University; Department of Biochemistry, West Virginia University.
authors: Mark
authors: M
authors: Tseytlin
authors: Department of Chemistry and Biochemistry, University of Denver.
authors: Hanan
authors: H
authors: Elajaili
authors: Department of Electrical and Computer Engineering, University of Denver.
authors: George A
authors: GA
authors: Rinard
authors: Department of Engineering, University of Denver.
authors: Richard W
authors: RW
authors: Quine
authors: Department of Chemistry and Biochemistry, University of Denver.
authors: Sandra S
authors: SS
authors: Eaton
authors: Department of Chemistry and Biochemistry, University of Denver; gareth.eaton@du.edu.
authors: Gareth R
authors: GR
authors: Eaton
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010100:Oxygen; D019047:Phantoms, Imaging; D011877:Radionuclide Imaging; D015398:Signal Transduction
chemical_list: D010100:Oxygen