Performance of image reconstrucion algorithms in electron paramagnetic resonance tomography with multiharmonic analysis

Electron Paramagnetic Resonance (EPR) Tomography is promising imaging technique that allows to yield maps of spatial distribution of radical concentration and oxygen concentration. The principle of obtaining those maps is based on inversion of the Radon transform as in other tomographic systems such as traditional X-ray computed tomography and emission tomography. In this article the tomographic image reconstruction algorithms are analyzed in terms of their usefulness in the recently built EPR tomography system. In the paper the authors also described the electronic device capable to record multiple harmonics (to the thirtieth harmonic inclusive) of the electron paramagnetic resonance absorption signals. The extension set is able to work with the EPR spectrometer (Bruker ELEXSYS-II E540) and other commercial systems. Along with specialized software it might be used to perform analysis of recorded harmonics to restore the proper absorption spectrum from the overmodulated signals. The results of using such device to improve the quality of the final images were presented.