A new strategy for fast radiofrequency CW EPR imaging: Direct detection with rapid scan and rotating gradients

Abstract

Rapid field scan on the order of T/s using high frequency sinusoidal or triangular sweep fields superimposed on the main Zeeman field, was used for direct detection of signals without low-frequency field modulation. Simultaneous application of space-encoding rotating field gradients have been employed to perform fast CW EPR imaging using direct detection that could, in principle, approach the speed of pulsed FT EPR imaging. The method takes advantage of the well-known rapid-scan strategy in CW NMR and EPR that allows arbitrarily fast field sweep and the simultaneous application of spinning gradients that allows fast spatial encoding. This leads to fast functional EPR imaging and, depending on the spin concentration, spectrometer sensitivity and detection band width, can provide improved temporal resolution that is important to interrogate dynamics of spin perfusion, pharmacokinetics, spectral spatial imaging, dynamic oxymetry, etc.

Assessing Tumor Oxygenation for Predicting Outcome in Radiation Oncology: A Review of Studies Correlating Tumor Hypoxic Status and Outcome in the Preclinical and Clinical Settings

“…This increases the acquisition time. However, EPRI has demonstrated its ability to image oxygenation levels quantitatively in vitro and to map tumor hypoxia in preclinical models using a triarylmethyl probe (154, 155). A few researchers have developed home-made “Pulsed” EPR systems that work in the same way as MRI scanners available nowadays.…”

Nitroxide Spin-Labelling and Its Role in Elucidating Cuproprotein Structure and Function

“…This leads to a lack of temporal sensitivity which can mask important biological events. Recent technological advances have reduced acquisition times for spectral-spatial imaging thereby making the technique attractive for biologically rapid events and even for low signal-to-noise probes [67][68][69][70].…”

Rapid-Scan EPR of Nitroxide Spin Labels and Semiquinones

“…Krishna laboratory (Subramanian et al, 2007). Published rapid-scan imaging experiments have been performed with phantoms of TCNQ (Subramanian et al, 2007), LiPc (Czechowski et al, 2014), nitroxides (Aminov, Tseitlin, & Salikhov, 1999; Biller et al, 2015; Biller et al, 2014b; M. Tseitlin et al, 2014) and pH-sensitive amino substituted trityl radicals (Elajaili, Biller, Tseitlin, et al, 2015).…”