First experimental evidence of the feasibility of multi-color magnetic particle imaging

TLDR

Magnetic particle imaging is a new 3D real‑time in vivo imaging technique for magnetic nanoparticles that has so far only imaged one particle type at a time, and separating signals from different particle types or environments would greatly expand its utility, although prior spectroscopic experiments showed signal separation but its performance with spatial encoding was unclear. This work aims to experimentally demonstrate that signals from different particle types and aggregation states can be separated using a multi‑color reconstruction approach. The authors discuss several mechanisms that could enable successful signal separation and propose assigning different colors to distinct signal sources to visualize them in a single image. The experimental results provide the first evidence that signals from fluid versus powder particle states and different particle types can be successfully separated, confirming the feasibility of multi‑color magnetic particle imaging.

Abstract

Magnetic particle imaging is a new approach to visualizing magnetic nanoparticles. It is capable of 3D real-time in vivo imaging of particles injected into the blood stream and is a candidate for medical imaging applications. To date, only one particle type has been imaged at a time, however, the ability to separate signals acquired simultaneously from different particle types or from particles in different environments would substantially increase the scope of the method. Different colors could be assigned to different signal sources to allow for visualization in a single image. Successful signal separation has been reported in spectroscopic experiments, but it was unclear how well separation would work in conjunction with spatial encoding in an imaging experiment. This work presents experimental evidence of the separability of signals from different particle types and aggregation states (fluid versus powder) using a 'multi-color' reconstruction approach. Several mechanisms are discussed that may form the basis for successful signal separation.