Evaluating selection criteria for optimized excitation coils in magnetorelaxometry imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Nanotechnology

Background:

• Magnetorelaxometry imaging (MRXI) is an experimental technique for noninvasive imaging of magnetic nanoparticles (MNPs).
• Accurate MNP distribution reconstruction is vital for MNP-based therapies like magnetic drug targeting and hyperthermia.
• Current MRXI optimization approaches lack a clear understanding of which figures of merit yield the best reconstruction accuracy.

Purpose of the Study:

• To compare different figures of merit for MRXI optimization.
• To determine the most reliable and effective optimization approach for MRXI setups.
• To enhance the accuracy of nanoparticle distribution reconstructions for improved therapeutic applications.

Main Methods:

• Figures of merit were translated into cost functions for optimizing electromagnetic coil positions and radii in two MRXI setups.
• An adapted tabu search algorithm was employed for the optimization process.
• Artificial MNP phantoms were reconstructed using the optimized setups, and imaging quality was compared.

Main Results:

• The condition number was identified as the most reliable indicator for achieving good qualitative and quantitative reconstruction accuracies.
• Extensive synthetic data generation provided unprecedented insights into MRXI performance metrics.
• Optimized coil configurations demonstrated superior reconstruction quality compared to existing state-of-the-art methods.

Conclusions:

• Optimizing MRXI coil configurations significantly increases reconstruction quality.
• The condition number is a key metric for guiding MRXI system design and optimization.
• These findings can lead to safer and more efficient MNP-based medical treatments.