Abstract
This review provides an in-depth examination of the critical functions served by the Field Free Point (FFP) and Field Free Line (FFL) within Magnetic Particle Imaging (MPI), particularly highlighting their importance for improving imaging accuracy and resolution. Basic FFP and FFL configurations and experimental conditions are presented first, followed by an evaluation of their impact on MPI protocol optimization. It delves deeper into the synthesis and functionalization of magnetic nanoparticles, highlighting their uses in targeted MPI and theragnostic. A comparison of FFP and FFL designs is presented to emphasize their benefits, limits, and possible contributions to trajectory optimization. The analysis continues with prospective future research areas that try to address existing challenges while improving MPI technology for both medical diagnostics and industrial applications.