First Superferromagnetic Remanence Characterization and Scan Optimization for Super-Resolution Magnetic Particle Imaging

作者：K. L. Barry Fung, Caylin Colson, Jacob Bryan, Chinmoy Saayujya, Javier Mokkarala-Lopez, Allison Hartley, Khadija Yousuf, Renesmee Kuo, Yao Lu, Benjamin Fellows, Prashant Chandrasekharan, Steven Conolly · 发表于：Nano Letters · 年份：2023 · DOI：10.1021/acs.nanolett.2c04404 · 被引用次数：30 · 研究领域：Characterization and Applications of Magnetic Nanoparticles、Geomagnetism and Paleomagnetism Studies、Microfluidic and Bio-sensing Technologies

Magnetic particle imaging (MPI) is a sensitive, high-contrast tracer modality that images superparamagnetic iron oxide nanoparticles, enabling radiation-free theranostic imaging. MPI resolution is currently limited by scanner and particle constraints. Recent tracers have experimentally shown 10× resolution and signal improvements with dramatically sharper M-H curves. Experiments show a dependence on interparticle interactions, conforming to literature definitions of superferromagnetism. We thus call our tracers superferromagnetic iron oxide nanoparticles (SFMIOs). While SFMIOs provide excellent signal and resolution, they exhibit hysteresis with non-negligible remanence and coercivity. We provide the first quantitative measurements of SFMIO remanence decay and reformation using a novel multiecho pulse sequence. We characterize MPI scanning with remanence decay and coercivity and describe an SNR-optimized pulse sequence for SFMIOs under human electromagnetic safety limitations. The resolution from SFMIOs could enable clinical MPI with 10× reduced scanner selection fields, reducing hardware costs by up to 100×.