Evaluation and comparison of pulsed and continuous wave radiofrequency electron paramagnetic resonance techniques for in Vivo detection and imaging of free radicals

Ken Ichi Yamada, Ramachandran Murugesan, Nallathamby Devasahayam, John A. Cook, James B. Mitchell, Sankaran Subramanian, Murali C. Krishna

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

The performance of two electron paramagnetic resonance (EPR) spectrometers/imagers, one configured in pulsed mode and the other in continuous wave (CW) mode, at an operating frequency of 300 MHz is compared. Using the same resonator (except for altered Q-factors), identical samples and filling factors in the two techniques have been evaluated for their potentials and limitations for in vivo spectroscopic and imaging applications. The assessment is based on metrics such as sensitivity, spatial and temporal resolution, field of view, image artifacts, viable spin probes, and subjects of study. The spectrometer dead time limits the pulsed technique to samples with long phase memories (>275 ns). Nevertheless, for viable narrow-line spin probes, the pulsed technique offers better sensitivity and temporal resolution. The CW technique, on the other hand, does not restrict the choice at spin probes. In addition, the phase-sensitive narrow-band detection of the CW technique gives artifact-free images even for large objects. Selected examples illustrating the performance of the CW and pulsed techniques are presented to put the capabilities of the two techniques in perspective.

Original languageEnglish
Pages (from-to)287-297
Number of pages11
JournalJournal of Magnetic Resonance
Volume154
Issue number2
DOIs
Publication statusPublished - 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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