Vicinity Effects of Field Free Point on the Relaxation Behavior of MNPs

TL;DR

This paper investigates how the DC field from the selection field affects the relaxation behavior of magnetic nanoparticles near the field free point in Magnetic Particle Imaging, aiming to explain differences observed between spectrometer and scanner measurements.

Contribution

It provides new insights into the influence of the DC field on MNP relaxation behavior in MPI, clarifying discrepancies between different measurement setups.

Findings

DC field significantly alters MNP relaxation near the FFP

Differences between MPS and MPI relaxations are explained by DC field effects

Enhanced understanding of MNP behavior improves MPI imaging accuracy

Abstract

In Magnetic Particle Imaging (MPI), the distribution of magnetic nanoparticles (MNPs) is imaged by moving a field free point (FFP) in space. All MNPs in close vicinity of the FFP contribute to the signal induced on the receive coil. The relaxation behavior of these MNPs are subject to a DC field due to the selection field (SF). In this work, we investigate the effects of the DC field on the relaxation behavior of the MNPs, with the goal of understanding the differences between the measured relaxations in Magnetic Particle Spectrometer (MPS) setups vs. MPI scanners.