Development of Low-Frequency Magnetic Particle Imaging System with Enhanced Image Reconstruction Utilizing Even Harmonics

In this study, a magnetic particle imaging (MPI) system that uses the nonlinear magnetization properties of magnetic nanoparticles was driven at a low frequency of several hundred Hz to achieve significantly lower power consumption (about 10 Wh) than conventional systems. First, two types of MPI systems with parallel and vertical magnetic fields were fabricated and their advantages and challenges were compared. Furthermore, we propose a method for effectively utilizing even harmonics in MPI signal processing, whereas in the past only odd harmonics were mainly used for imaging, by applying integral processing to even harmonics. Experimental results show that the use of all harmonic components including even numbers can simultaneously increase signal strength and improve resolution. These results suggest that the combination of active use of even harmonics and the low-frequency drive proposed in this study is a promising approach for increasing sensitivity and saving energy for MPI systems in the future.