Magnetic Particle Imaging. Behr, Volker; Jakob, Peter in Z. Med. Phys. (2015). 25(1) 1–2.
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Bimodal TWMPI-MRI Hybrid Scanner - Coil Setup and Electronics. Klauer, Peter; Vogel, Patrick; Rückert, Martin Andreas; Kullmann, Walter H; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 5300504.
Magnetic particle imaging (MPI) is a novel imaging method for the depiction of superparamagnetic materials. Since the first publication several MPI scanner were presented, which work at gradient strength of ~2-7 T/m. This is reasonable for in vivo imaging and provides a resolution of ~1 mm. In this paper, several approaches for a micro-MPI (μMPI) device for very small samples are presented, which works at a very high magnetic gradient strength of ~85 T/m. This results in a theoretical resolution <100 μm. This μMPI device can be operated at several modes, which have different advantages. In preliminary tests, the feasibility of the μMPI device has been proven.
Simulating the Signal Generation of Rotational Drift Spectroscopy. Rückert, Martin Andreas; Vogel, Patrick; Kampf, Thomas; Kullmann, Walter H; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 6500704.
Since the first publication in 2005, several different scanner types for magnetic particle imaging (MPI) have been presented. One of these scanner concepts is traveling wave MPI (TWMPI). It uses a dynamic linear gradient array, which generates and moves a field free point with a strong gradient, which is necessary for scanning the sample in 3-D. Due to the linear properties of the TWMPI device, very fast 2-D imaging with frame rates higher than 1500 frames/s is possible (superspeed mode). Using the superspeed mode different high speed measurements are conceivable, e.g., fluid-dynamic investigations.
Rotational Drift Spectroscopy for Magnetic Particle Ensembles. Rückert, Martin Andreas; Vogel, Patrick; Vilter, Anna; Kullmann, Walter H; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 6500604.
Magnetic particles have become a core ingredient for many applications in chemistry, biology, and medical diagnostics, e.g., as basis for bioanalytical methods or tracer material for medical imaging. This paper discusses the theory and presents numerical simulations of a new method called rotational drift spectroscopy (RDS), which uses rotating magnetic fields for measuring the properties of magnetic nanoparticles (MNPs) in liquid suspensions. The RDS signal is based on the nonlinear rotational drift behavior of MNPs in rotating magnetic fields, which is highly dependent on the properties of the MNPs as well as their interaction with the environment. This dependence makes it a highly promising tool for detecting the binding of functionalized MNPs with, e.g., proteins, viruses, or cells. This paper presents the theory and numerical simulations of this method.
μMPI - Initial Experiments With an Ultrahigh Resolution MPI. Vogel, Patrick; Rückert, Martin Andreas; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 6502104.
Magnetic particles have become a core ingredient for many applications in chemistry, biology, and medical diagnostics, e.g., as a basis for bioanalytical methods or as tracer material for medical imaging. This paper presents a new method called rotational drift spectroscopy (RDS) which uses rotating magnetic fields for measuring the properties of magnetic nanoparticles (MNPs) in liquid suspensions. The RDS signal is based on the nonlinear rotational drift behavior of MNPs in rotating magnetic fields, which is highly dependent on the properties of the MNPs as well as their interaction with the environment. This dependency allows detecting the binding of functionalized MNPs with, e.g., proteins, viruses, or cells with potentially very high sensitivity. This paper presents first experiments demonstrating rotational drift behavior on aggregated magnetic particle ensembles and the corresponding experimental setup.
Superspeed Traveling Wave Magnetic Particle Imaging. Vogel, Patrick; Rückert, Martin Andreas; Klauer, Peter; Kullmann, Walter H; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 6501603.
Since the introduction of magnetic particle imaging in 2005, several different types of scanner were presented. One of them is the traveling wave magnetic particle imaging (TWMPI) scanner. It uses for imaging a dynamic linear gradient array for a dynamic generation of a strong gradient and field free point. An unresolved issue of the TWMPI approach so far is the non-isotropic spatial resolution. As an alternative in this paper, a rotating slice scanning mode for TWMPI is presented to overcome this issue. This approach rotates the scanning-slices around the scanner axis and uses a projection reconstruction method to get a 3-D volume with a high isotropic resolution.
Rotating Slice Scanning Mode for Traveling Wave MPI. Vogel, Patrick; Rückert, Martin Andreas; Klauer, Peter; Kullmann, Walter H; Jakob, Peter Michael; Behr, Volker Christian in IEEE Trans. Magn. (2015). 51(2) 6501503.
Magnetic particle imaging (MPI) was first presented in 2005. It is based on the nonlinear response of ferromagnetic material and the fact that the magnetization saturates at sufficiently high magnetic fields. In contrast to magnetic resonance imaging (MRI), MPI directly detects the concentration and distribution of superparamagnetic iron-oxide nanoparticles without any background of any tissue. To overcome this issue, a traveling wave MPI (TWMPI) device was combined with a low field MRI scanner to demonstrate the feasibility of a hybrid scanner, which contains both imaging modalities in a single device. The hardware of both separate approaches should be improved and optimized to reach higher fields and a higher resolution, especially for the MRI measurement. Therefore, the dynamic linear gradient array from the TWMPI scanner was modified in a way to produce also a homogenous magnetic field, which can be used for MRI.