YIG-based magnetorelaxometry: Sensor Design, Fused Lasso Inversion, and Metrological Validation

The applications of magnetic particles (MPs) in biomedicine require highly sensitive detection and localization techniques. Recently, a novel magnetometer based on yttriumiron-garnet (YIG) film has been developed, showing promise as a practical tool for advanced studies on MPs because of its low cost, fast recovery time, and high sensitivity. In this work, we focus on the application of the YIG magnetometer for reconstructing the spatial distribution of MP concentration using magnetorelaxometry (MRX), a technique that provides information about MP concentration distributions. Our approach employs fused Lasso regularization to solve the MRX inverse problem, combining ℓ 1norm sparsity with total variation (TV) edge preservation to enhance reconstruction accuracy and robustness. Experimental validation utilized a device composed of a YIG magnetometer and a dual-coil excitation system to measure relaxation signals from MPs (submicron Fe3O4 rods) under different multi-activated external magnetic fields. The results highlight the high capability of the YIG magnetometer to accurately recover MP distributions, showcasing its potential for magnetic imaging applications.