An application system for automation of constant-time radio frequency electron paramagnetic resonance imaging

A Windows based application system for data collection, Fourier reconstruction and analysis of pure phase encoded constant-time radio frequency electron paramagnetic resonance (EPR) images, is described. The graphical user interface (GUI) of the system was written in MATLAB version 5.0, using its built-in GUI utilities. Design considerations of the application system included speed, flexibility and user-friendly data display and analysis. To maximize the speed of image data collection, MATLAB's built-in C interface system, MEX was not used for data collection. Instead, MATLAB programs call the C programs from the DOS prompt directly, based on the data collection parameters entered through the GUI. Computational procedures included various digital signal-processing steps such as filtering, interpolation etc. for the Fourier reconstruction of 2D, and 3D EPR images from the pure phase encoded data. Examples of 2D images illustrating the performance of the system are presented. Although the application system has been developed for the specific purpose of EPR imaging, it can easily be adapted to other areas such as magnetic resonance microscopy as well.