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The design, construction and use of a large-scale field-cycled proton-electron double-resonance imaging (FC-PEDRI) imager is described. The imager is based on a whole-body sized, vertical field, 59 mT permanent magnet. Field cycling is accomplished by the field compensation method, and uses a secondary, resistive magnet with an internal diameter of 52 cm.(More)
Fast field-cycling MRI offers access to sources of endogenous information not available from conventional fixed-field imagers. One example is the T(1) dispersion curve: a plot of T(1) versus field strength. We present a pulse sequence that combines saturation-recovery/inversion-recovery T(1) determination with field cycling and point-resolved spectroscopy(More)
Electron Paramagnetic Resonance (EPR, or ESR) is a powerful non-invasive spectroscopic tool that can be used to monitor drug release processes in vitro and in vivo. Furthermore, spatial dissolution can be achieved by means of EPR-Imaging. The article introduces the basics of EPR and EPR-imaging. It discusses also the challenges of in vivo spectroscopy and(More)
Proton-electron double-resonance imaging (PEDRI) has considerable value for study of the distribution and elimination pathways of nitroxide free radicals (NFRs). This has been illustrated by its use in studies of kidney function in the living rat in which the NFR proxyl carboxylic acid (PCA) has been employed as a 'tracer'. The technique, at its present(More)
The determination of pH is one of the most important problems in the biochemistry of living organisms, since many of the vital processes of cells and cellular organelles depend on the local pH value. Amongst currently used experimental approaches for the measurement of pH, the application of spin pH probes in combination with EPR spectroscopy is a(More)
This paper describes the design, construction and use of a field-cycled proton-electron double-resonance imaging (FC-PEDRI) system for the detection and imaging of free radicals. The unique feature of this imager is its use of a 450-mT detection magnetic field in order to achieve good image quality and sensitivity. The detection magnetic field is provided(More)
Proton electron double resonance imaging (PEDRI) uses the Overhauser effect to image the distribution of free-radicals in biological samples and animals. Standard MRI hardware and software is used, with the addition of hardware to irradiate the free-radical-of-interest's EPR resonance. For in vivo applications it must be implemented at a sufficiently low(More)
Proton electron double resonance imaging (PEDRI) measures the spatial distribution of paramagnetic species in biological samples using the Overhauser effect. Triaryl methyl (TAM) free radicals have been developed as a spin probe for PEDRI since they have very long T(1e). Therefore, low RF power levels are sufficient to saturate the electron spin system with(More)
A prototype continuous wave MRI system operating at 7T has been used successfully to study a variety of heterogeneous materials exhibiting T2 relaxation values ranging from 10 micros to 50 ms. Two-dimensional images of a poly(methly methacrylate) (PMMA) resolution phantom (T2=38 micros) exhibited a spatial resolution of approximately 1mm at a magnetic field(More)
The development of a 3-D, multi-nuclear continuous wave NMR imaging (CW-NMRI) system is described and its imaging capability is demonstrated on a range of materials exhibiting extremely short T(2) relaxation values. A variety of radiofrequency resonators were constructed and incorporated into a new gradient and field offset coil assembly, while the overall(More)