Development of Phantoms for Multimodal Magnetic Resonance Imaging and Magnetic Particle Imaging

Abstract

Phantoms are crucial for the development of imaging techniques based on magnetic nanoparticles (MNP). They serve as test objects to simulate application scenarios but are also used for quality assurance and interlaboratory comparisons. Magnetic particle imaging (MPI) is excellent for specifically detecting magnetic nanoparticles (MNP) without any background signals. To obtain information about the surrounding soft tissue, MPI is often used in combination with magnetic resonance imaging (MRI). For such application scenarios, this poses a challenge for phantom fabrication, as they need to accommodate MNP as well as provide MR visibility. Recently, layer-by-layer fabrication of parts using Additive Manufacturing (AM) has emerged as a powerful tool for creating complex and patient-specific phantoms, but these are characterized by poor MR visibility of the AM material. We present the systematic screening of AM materials as candidates for multimodal MRI/MPI imaging. Of all investigated materials, silicone (Dreve, Biotec) exhibited the best properties with sufficient MR-signal performance and the lowest absorption of MNP at the interface of AM materials. With the help of AM and the selection of appropriate materials, we have been able to produce suitable MRI/MPI phantoms.

Monitoring magnetic nanoparticle clustering and immobilization with thermal noise magnetometry using optically pumped magnetometers

“…The slow magnetization dynamics of the aggregated MNPs and the broad size distribution of their fluctuation times are a distinctive signature of this process which was depicted schematically in Fig 1 .2c. phantom design and fabrication 65,66 . In our experiment, a photopolymer was mixed with Perimag ® particles to mimic the gradual change in mobility of the particles when being embedded in the target tissue.…”

“…In combination with magnetic nanoparticles, they are of particular interest for precise phantom design and fabrication. 65,66 In our experiment, a photopolymer was mixed with Perimag® particles to mimic the gradual change in mobility of the particles when being embedded in the target tissue.…”