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Item type:Publication, Access status: with files , Topology considerations for an iron-core coil module field generator(Infinite Science Publishing, 2026-03-18); ; ; ; The selection-field generator of a Magnetic Particle Imaging (MPI) scanner is typically the system’s largest power consumer. For potential use in intensive care units, it would be highly desirable to operate MPI scanners from a standard wall outlet without dedicated high-power infrastructure. Several concepts for more efficient selection-field generation have been proposed in recent years. In this work, we propose a novel generator design based on an array of soft-iron core coils arranged at an angle around the scanner bore. This geometry reduces overall electrical power demand while enabling gradient strengths of up to 0.5 T m¹. The design was simulated and optimized using magnetostatic simulations in COMSOL Multiphysics. To ensure reliable modeling of the soft-iron cores, prototype coils were built and their magnetic fields were measured, providing experimental validation of the simulation models.Publicationtype: Journal Article7 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Correction to: System characterization of a human-sized 3D real-time magnetic particle imaging scanner for cerebral applications (Communications Engineering, (2024), 3, 1, (47), 10.1038/s44172-024-00192-6)(Springer, 2024-12); ; ; ; Correction to: Communications Engineeringhttps://doi.org/10.1038/s44172-024-00192-6, published online 14 March 2024 Author correction: In the original version of this Article, financial support from the Open Access Publication Fund of UKE - Universitätsklinikum Hamburg-Eppendorf was not acknowledged. This has now been corrected in both the PDF and HTML versions of the Article. The Acknowledgements section needs to be revised to: We thank Florian Sevecke for technical support during the realization of numerous scanner components. We further thankfully acknowledge the financial support by the German Research Foundation (DFG, grant numbers KN 1108/7-1 and GR 5287/2-1). We also thank the developers of Makie.jl supporting us by answering technical questions when creating Figs. 3 and 4. Finally, we are grateful to Christian Findeklee for their discussions and insights into resonant circuit decoupling. We acknowledge financial support from the Open Access Publication Fund of UKE - Universitätsklinikum Hamburg-Eppendorf.Publicationtype: Corrigendum41 19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Resonant inductive coupling network for human-sized magnetic particle imaging(2024-04-01); ; ; ; In magnetic particle imaging, a field-free region is maneuvered throughout the field of view using a time-varying magnetic field known as the drive-field. Human-sized systems operate the drive-field in the kHz range and generate it by utilizing strong currents that can rise to the kA range within a coil called the drive field generator. Matching and tuning between a power amplifier, a band-pass filter, and the drive-field generator is required. Here, for reasons of safety in future human scanners, a symmetrical topology and a transformer called an inductive coupling network are used. Our primary objectives are to achieve floating potentials to ensure patient safety while attaining high linearity and high gain for the resonant transformer. We present a novel systematic approach to the design of a loss-optimized resonant toroid with a D-shaped cross section, employing segmentation to adjust the inductance-to-resistance ratio while maintaining a constant quality factor. Simultaneously, we derive a specific matching condition for a symmetric transmit-receive circuit for magnetic particle imaging. The chosen setup filters the fundamental frequency and allows simultaneous signal transmission and reception. In addition, the decoupling of multiple drive field channels is discussed, and the primary side of the transformer is evaluated for maximum coupling and minimum stray field. Two prototypes were constructed, measured, decoupled, and compared to the derived theory and method-of-moment based simulations.Publicationtype: Journal Article5 59 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , System characterization of a human-sized 3D real-time magnetic particle imaging scanner for cerebral applications(Springer, 2024-03-14); ; ; ; Since the initial patent in 2001, the Magnetic Particle Imaging community has endeavored to develop a human-applicable Magnetic Particle Imaging scanner, incorporating contributions from various research fields. Here we present an improved head-sized Magnetic Particle Imaging scanner with low power consumption, operated by open-source software and characterize it with an emphasis on human safety. The focus is on the evaluation of the technical components and on phantom experiments for brain perfusion. We achieved 3D single- and multi-contrast imaging at 4 Hz frame rate. The system characterization includes sensitivity, resolution, perfusion and multi-contrast experiments as well as field measurements and sequence analysis. Images were acquired with a clinically approved tracer and within human peripheral nerve stimulation thresholds. This advanced scanner holds potential as a tomographic imager for diagnosing conditions such as ischemic stroke (different stages) or intracranial hemorrhage in environments lacking electromagnetic shielding, such as the intensive care unit.Publicationtype: Journal Article23 47 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Trade-off between power consumption and receive signal strength for inductively coupled transmit-receive circuits in MPI(Infinite Science Publishing, 2024-03-10); ; ; ; The signal chain of a Magnetic Particle Imaging system can be designed to include a dedicated receive-only coil or to combine transmit and receive coils. More common are circuits with separate transmit and receive chains, using dedicated receive coil(s) that cancel the excitation feedthrough. However, combined transmit-receive systems may prove to have several benefits, such as reducing the system complexity, providing a lower resistive noise contribution due to larger copper cross-section, facilitating a transition from 1D to multidimensional signal generation and acquisition, and implementing an embedded band-stop filter. In this theoretical work, a matching condition that governs inductors for resonant combined transmit-receive systems is investigated. To tap the signal, a compromise between the obtained signal strength and power consumption is considered, caused by the chosen circuit topology, that balances both signal loss and power consumption at a −3 dB benchmark.Publicationtype: Journal Article11 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , MPIMeasurements.jl : an extensible Julia framework for composable magnetic particle imaging devices(Infinite Science Publishing, 2023-03-19); ; ; ; Magnetic particle imaging (MPI) is a pre-clinical imaging modality, whose system design is still evolving, in particular towards human studies and clinical use. Therefore, many MPI scanners are custom-made distributed systems, both on the hard-and the software side. In this work we present the open-source Julia framework MPIMeasurements.jl, which implements a composable representation of imaging systems. It also offers flexible data structures that allow the implementation of specific imaging protocols, such as online/offline measurements, repeated measurements and system matrix calibrations. The project is designed to be expanded to new systems through community development and component reuse. To showcase the versatility of the software package, we give an overview of four very different MPI systems, which were realized with MPIMeasurements.jl.Publicationtype: Journal ArticleScopus© Citations 3 26 195 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Safe and rapid 3D imaging : upgrade of a human-sized brain MPI system(Infinite Science Publishing, 2023-03-19); ; ; ; Magnetic Particle Imaging hardware has reached human scale and thus patient safety questions and clinical application scenarios are in the focus of current research. In this work, we present a safe real-time 3D MPI system for cerebral applications. High voltages are avoided to ensure patient safety by a low voltage-high current transmit coil design. The developed 2D drive-field generator generates a field-free-point trajectory in the sagittal xz-plane that is shifted with low frequency by a dynamic selection-field sequence along the y-axis. The scanner generates 3D images with 4 frames/second and allows for direct visualization of the clinically preferred transversal yz-plane, which is crucial for future brain examinations. Advanced reconstruction techniques reach a system sensitivity of 4 µgFe with respect to the iron mass in a sensitivity study.Publicationtype: Journal ArticleScopus© Citations 2 38 79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Flexible selection field generation using Iron core coil arrays(Infinite Science Publishing, 2023-03-19); ; ; ; Many different concepts for selection-field generators have been introduced for Magnetic Particle Imaging so far. In this work, the field generation characteristics of an optimized iron core selection-field generator consisting of two coil arrays with a total of 18 coils are presented. Due to the high number of degrees of freedom, a wide variety of field configurations are possible. The setup allows the generation of arbitrarily shaped fields, including the standard Magnetic Particle Imaging fields such as field-free points and field-free lines. In this work, measurements of static magnetic fields are presented and the current calculation method for generating a specific field configuration is discussed.Publicationtype: Journal ArticleScopus© Citations 2 30 57 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , On the Receive Path Calibration of Magnetic Particle Imaging SystemsMagnetic nanoparticles are a valuable tool in many biomedical applications and can be used for diagnostic and therapeutic purposes. In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS), the particles are subjected to a dynamic magnetic field and the particle magnetization response is simultaneously measured using one or multiple receive coils. Separating the particle signal from the feed-through signal is commonly done by advanced passive filtering, which distorts the particle signal. To correct this distortion, the transfer function of the receive chain needs to be known. While in principle, the transfer function can be simulated, due to imperfections in the electronic components, it is often more accurate to determine the transfer function in a calibration procedure. Although this system calibration, utilizing a calibration-coil setup has been done by several research groups in the past, a general description of the underlying calibration model and methodology is still missing. In this paper we provide a general multi-channel calibration procedure for inductive receive paths in MPI and a blueprint to investigate model and method uncertainties. We generalized the calibration procedure to also cover non-orthogonal and non-homogeneous receive coils. Finally, we showcase the calibration procedure and uncertainty analysis on our custom MPS system and use the MPI transfer functions of misaligned receive coils to decouple their superimposed receive signals from the receive path. The findings enable the comparison of MPI signals from different devices and can be used to normalize measurements and system functions in devices with exchangeable receive coils.Publicationtype: Journal Article35 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Low-power Iron selection and focus field generator(Infinite Science Publishing, 2022-03-21); ; ; ; A major issue for human-sizedMagnetic Particle Imaging scanners is the generation of sufficiently large magnetic gradient fields. By taking advantage of the field amplification properties of soft-iron, a considerable amount of power can be saved. In this work, an optimized selection and focus field generator is presented, that can generate flexible and high gradient fields at comparatively lowpower consumption. Coil spacing and possible field-free-point positions are similar to conventional MPI scanners designed with air coils, but with significantly less demands on infrastructure and cooling design. The optimization process is discussed and first field measurements are presented.Publicationtype: Journal ArticleScopus© Citations 2 36 85