MPI Phantom Study with A High-Performing Multicore Tracer Made by Coprecipitation

Magnetic particle imaging (MPI) is a new imaging technique that detects the spatial distribution of magnetic nanoparticles (MNP) with the option of high temporal resolution. MPI relies on particular MNP as tracers with tailored characteristics for improvement of sensitivity and image resolution. For this reason, we developed optimized multicore particles (MCP 3) made by coprecipitation via synthesis of green rust and subsequent oxidation to iron oxide cores consisting of a magnetite/maghemite mixed phase. MCP 3 shows high saturation magnetization close to that of bulk maghemite and provides excellent magnetic particle spectroscopy properties which are superior to Resovist® and any other up to now published MPI tracers made by coprecipitation. To evaluate the MPI characteristics of MCP 3 two kinds of tube phantoms were prepared and investigated to assess sensitivity, spatial resolution, artifact severity, and selectivity. Resovist® was used as standard of comparison. For image reconstruction, the regularization factor was optimized, and the resulting images were investigated in terms of quantifying of volumes and iron content. Our results demonstrate the superiority of MCP 3 over Resovist® for all investigated MPI characteristics and suggest that MCP 3 is promising for future experimental in vivo studies

A multi-purpose phantom kit for magnetic particle imaging

Phantoms are essential tools for the development and characterization of Magnetic Particle Imaging (MPI), an imaging technique that can quantitatively map the spatial distribution of magnetic nanoparticles (MNP). The objective of this study was to develop and validate a modular MPI phantom kit with high versatility for platform-independent quality assurance and the assembling of defined geometries in MPI. It was shown that the developed MPI phantom kit can be used for both application scenario testing and quality assurance in MPI which provides the basis for future reference phantoms to directly compare existing scanners within the MPI community

A reference dataset for verifying numerical electrophysiological heart models

<p>Abstract</p> <p>Background</p> <p>The evaluation, verification and comparison of different numerical heart models are difficult without a commonly available database that could be utilized as a reference. Our aim was to compile an exemplary dataset.</p> <p>Methods</p> <p>The following methods were employed: Magnetic Resonance Imaging (MRI) of heart and torso, Body Surface Potential Maps (BSPM) and MagnetoCardioGraphy (MCG) maps. The latter were recorded simultaneously from the same individuals a few hours after the MRI sessions.</p> <p>Results</p> <p>A training dataset is made publicly available; datasets for blind testing will remain undisclosed.</p> <p>Conclusions</p> <p>While the MRI data may provide a common input that can be applied to different numerical heart models, the verification and comparison of different models can be performed by comparing the measured biosignals with forward calculated signals from the models.</p

3D printed measurement phantoms for evaluation of magnetic particle imaging scanner

To assess the potential and capability of different MPI scanner designs and architectures, defined reference phantoms for imaging studies are required. For the preparation of well-defined structures as well as realistic vessel structures, 3D printed molds were filled with magnetic nanoparticles embedded into a long term stable polymeric matrix or perfused with a flowing ferrofluid. Different types and layouts of 3D printed phantoms will be presented which were imaged by means of MPI successfully

Magnetic nanoparticle-gel materials for development of joint phantoms for MPI and MRI

To evaluate the performance of commercial as well as custom-made scanners, dedicated phantoms with defined magnetic nanoparticle (MNP) distributions are required. Prerequisite for the development of such phantoms is the establishment of suitable MNP-matrix combinations. In this study, two different gel types were investigated as potential matrix materials: water-based biopolymers and synthetic polymers. These materials exhibit similar imaging behaviour to body tissue in MRI and MPI. Aqueous suspensions of MNP coated with different types of functionalized dextranes were used for embedding particles into the biopolymers, and organic fluids with oleic acid coated MNP for synthetic polymers, respectively. The obtained MNP-matrix combinations were tested for their shape stability. The homogeneity of MNP distribution and immobilization within the matrix was determined by optical investigation of the samples with a microscope, and the magnetic properties of the composite materials measured by vibrating sample magnetometry. From the tested combinations of MNP and matrix material, oleic acid coated MNP embedded in Permagel was found to be the most suitable for the construction of MPI phantoms. This was based on the reliable and homogeneous fixation of the MNP within the matrix without agglomeration of the particles

Real-time bidding platform for public display networks

Die klassischen Bezahlmodelle werden nach und nach durch neue Finanzierungsmodelle ersetzt. Das am weitesten verbreiteste Bezahlmodell ist derzeit die Bezahlung mit Giralgeld. Eine andere Methode ist das sogenannte Advertising, das Dienste oder Services mit Werbung finanziert. Daher sind diese Dienste stark von einer Nutzerschaft und Werbenden abhängig, die ihre Werbung gegen eine Finanzierung an die Nutzerschaft ausliefert. Damit hat Advertising als Finanzierungsmodell ein großes Potential sich in der Zukunft zu etablieren. Diese Fachstudie beschäftigt sich mit der Implementierung und Evaluierung einer Real Time Bidding-Plattform für Public Display Networks, die Werbung von Werbetreibenden genauer an eine Zielgruppe von werbekonsumierenden Personen liefern soll. Eine Beschreibung der Real Time Bidding-Plattform, die Implementierung sowie die Evaluierung wird in dieser Fachstudie beschrieben