Petryakov, Sergey V., Maciej M. Kmiec, Conner S. Ubert, Victor B. Kassey, Philip E. Schaner, and Periannan Kuppusamy. “Surface Dielectric Resonator for in Vivo EPR Measurements.” Journal of Magnetic Resonance 362 (May 1, 2024): 107690.
https://doi.org/10.1016/j.jmr.2024.107690.
This research report describes a novel surface dielectric resonator (SDR) with a flexible connector for in vivo electron paramagnetic resonance (EPR) spectroscopy. Contrary to the conventional cavity or surface loop-gap resonators, the newly developed SDR is constructed from a ceramic dielectric material, and it is tuned to operate at the L-band frequency band (1.15 GHz) in continuous-wave mode. The SDR is designed to be critically coupled and capable of working with both very lossy samples, such as biological tissues, and non-lossy materials. The SDR was characterized using electromagnetic field simulations, assessed for sensitivity with a B1 field-perturbation method, and validated with tissue phantoms using EPR measurements. The results showed remarkably higher sensitivity in lossy tissue phantoms than the previously reported multisegment surface-loop resonators. The new SDR can provide potential new insights for advancements in the application of in vivo EPR spectroscopy for biological measurements, including clinical oximetry.