Abstract Magnetic particle imaging (MPI) quantitatively visualizes in vivo superparamagnetic iron oxide nanoparticles (SPIONs), which has shown great promises biomedicine. In this paper, we propose a single harmonic-based narrowband MPI approach via measuring harmonic—3 f 0 harmonic—of the SPIONs induced an excitation magnetic field with frequency = 5 kHz. The scanner is built to scan field-fre...