Development and optimization of three-dimensional spatial EPR imaging for biological organs and tissues

Area of Science:

• Biomedical Engineering
• Magnetic Resonance Imaging
• Spectroscopy

Background:

• Electron-paramagnetic-resonance imaging (EPRI) is a powerful technique for visualizing radical distribution.
• Imaging large, lossy biological samples presents significant challenges due to signal attenuation and field inhomogeneities.
• Previous methods lacked the resolution and accuracy for complex biological tissues.

Purpose of the Study:

• To develop and optimize 3D spatial EPRI for large, lossy samples at L-band frequencies.
• To establish robust correction strategies for instrumental and field inaccuracies.
• To achieve high-resolution imaging of radical distribution in biological samples.

Main Methods:

• Optimization of projection acquisition parameters and instrumentation for L-band EPRI.
• Development of algorithms for correcting microwave frequency drifts and magnetic field inaccuracies.
• Implementation of a two-stage filtered back-projection method with spectral deconvolution for image reconstruction.

Main Results:

• High-quality, spatially accurate 3D EPRI images of radical distribution were obtained in complex phantoms.
• Submillimeter resolution was achieved for samples up to 25 mm in size.
• Demonstrated feasibility for imaging lossy biological organs and tissues.

Conclusions:

• The developed L-band EPRI system and reconstruction methods enable high-fidelity 3D imaging of radical distribution in biological samples.
• This technique overcomes previous limitations in imaging lossy and large biological tissues.
• Offers a promising tool for preclinical research and diagnostics.