A mixing-frequency magnetic particle imaging (MPI) system is presented for high-throughput in-vivo studies. Coprime AC magnetic fields at 4.98 kHz and 97 Hz produce a field-free-point (FFP) scan in the x–y plane, which drive the MNPs to generate rich high-order harmonics and mixing-frequency components. All the mixing-frequency spectra of the MNPs are measured for image reconstruction. Phantom experimental results demonstrate the spatial resolution better than 1.5 mm at gradients of 0.64 T/m (x) and 1.28 T/m (y), and a limit of detection of 34.9 µmol/L Fe (?195 ng Fe). A scanning coil enables the 3D imaging speed of 0.5 min. A in-vivo murine study of cerebral blood-flow (CBF) imaging was acquired within a 30×30×30 mm³ FOV with clear delineation of anatomical structures. The mixing-frequency spectra-based approach combines hardware cost-effectiveness with good imaging performance, indicating strong potential for tumor diagnosis, cerebral perfusion, and longitudinal drug monitoring.
Sun et al. (Mon,) studied this question.