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Item type:Publication, Access status: with files , Variable gain amplifier for MPS(Infinite Science Publishing, 2026-04-23); ; ; The magnetic response of superparamagnetic iron oxide nanoparticles (SPIONs) varies significantly during nucle-ation and growth, requiring adaptive signal conditioning to avoid saturation and maintain sensitivity. This work presents the design and experimental characterization of a low-noise variable gain amplifier (VGA) based on the AD603 for this application. The VGA offers a pin-selectable gain range from −10 dB to +30 dB, enabling high gain at early synthesis stages and controlled attenuation at later stages. Performance was evaluated in terms of transient response, gain, phase behavior, and noise characteristics over a frequency range of 1 kHz to 1 MHz. Measurements demonstrate stable gain, limited phase variation, and improved noise performance through parallel amplifier configurations, indicating suitability for low-noise, high-dynamic-range SPIONs measurement systems such as MPS/MPI devices.Publicationtype: Journal Article17 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Comparison of human-scale MPI system concepts using a 3D arbitrary-waveform magnetic particle spectrometer(Infinite Science Publishing, 2026-03-18); ; ; In the field of Magnetic Particle Imaging (MPI) hybrid methods are utilizing the simplicity and high SNR of magnetic particle spectrometers to complement imaging by characterizing particles and measuring system matrices for fast system calibration. In this contribution we utilize the flexibility of our 3D arbitrary-waveform magnetic particle spectrometer to measure the system matrices of three MPI scanner concepts inspired by clinical-scale head-sized MPI systems. Using these system matrices we are able the compare reconstructed images under the same noise, particle and reconstruction conditions gathering first insights into the imaging properties of different scanners.Publicationtype: Journal Article12 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Randomized greedy Kaczmarz for multi-contrast magnetic particle imaging(Infinite Science Publishing, 2026-03-18); ; ; ; Multi-contrast magnetic particle imaging allows for separating signals from different tracer materials or microenvi-ronments from one joint measurement, yielding multi-channel images that distinguish tracers or encode properties such as temperature or viscosity. However, leakage artifacts enforce a noticeably longer application of iterative standard methods like the Kaczmarz algorithm to reach satisfactory reconstruction results. A greedy randomized version of the Kaczmarz method is adapted, showing the potential for faster recovery.Publicationtype: Journal Article16 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A low-noise differential JFET amplifier for magnetic particle imaging(Infinite Science Publishing, 2026-03-18); ; ; ; In MPI systems designed for large areas of the human body, drive fields are a significant source of interference for the receive electronics. Their influence, in addition to the direct feedthrough of the signal, can manifest itself in the form of common-mode noise, which can be effectively suppressed using filters and low-noise amplifiers with a differential architectures. In this work, we demonstrate a prototype of a low-noise amplifier based on a differential first stage, which works in combination with fourth-order notch receive filter. Our preliminary results show a gain of at least 40 dB over the frequency range of 50-700 kHz, effectively covering measurable harmonic signals for head-sized MPI scanner.Publicationtype: Journal Article12 8 - Some of the metrics are blocked by yourconsent settings
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 , Spherical harmonic-based receive coil array for a head MPI system(Infinite Science Publishing, 2026-03); ; ; ; A gradiometric receive coil is practically the modern standard in MPI. Although such a structure is one of the reliable and most effective ways of isolating the receive circuits from the influence of drive fields, it is challenging to implement it for the spatial sensitivity directions orthogonal to the cylinder axis of an MPI scanner. In this work, we demonstrate a concept of matrix coils based on spherical harmonic spatial sensitivity profiles. Our approach permits us to expand the number of independent receive channels in our head-sized MPI system to seven (and potentially more), while preserving important gradiometric characteristics of each channel.Publicationtype: Conference Paper10 6 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Normalized quantitative assessment of receive-coil sensitivity using MPI transfer function measurements(Infinite Science Publishing, 2026-03); ; ; ; In human-scale magnetic particle imaging (MPI), field inhomogeneities arise because a large fraction of the bore volume is utilized for imaging. Accurate knowledge of the receive-coil sensitivity is essential for hybrid systemmatrix generation and model-based system matrix reconstruction. In this work, we present an efficient approach for measuring normalized receive-field profiles using a calibration coil and a small number of measurements.Publicationtype: Conference Paper14 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Coordinate transformations for magnetic fields’ solid spherical harmonic coefficientsMagnetic particle imaging fundamentally relies on magnetic fields, so accurate characterization of the fields is crucial for various applications, such as sequence planning or model-based reconstructions. Magnetic fields can be compactly represented by solid harmonic expansions, whose coefficients efficiently describe the field distribution. However, in practice, the coordinate systems of measurement devices are not always perfectly aligned with the scanner’s coordinate system, complicating direct comparison and integration of measured data from different setups. In this work, we present methods for transforming solid harmonic coefficients under translations, rotations, and point reflections. These transformations enable consistent mapping of field representations into a common coordinate system, allowing direct comparison of magnetic fields obtained in different coordinate frames.Publicationtype: Conference Paper10 11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Current-to-field prediction for non-linear magnetic systems via neural networks(Infinite Science Publishing, 2025-03-14); ; ; ; Accurate magnetic field knowledge is crucial for magnetic particle imaging, affecting performance estimation, sequence generation, and reconstruction. Especially for non-linear field generators, such as those with built-in soft iron, conventional field simulations, such as the finite element method, are computationally demanding. We propose the use of neural networks to predict the coefficients of the spherical harmonic expansions of the fields from the input currents, drastically speeding up current-to-field prediction.Publicationtype: Journal Article8 14 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Power-efficient control of non-linear magnetic field generators for MPI(Infinite Science Publishing, 2025-03-14); ; ; The scaling of electrical power constitutes a significant challenge when adapting Magnetic Particle Imaging (MPI) to a human scale. The use of coils incorporating soft-iron cores serves to reduce power usage, but also introduces spatial imperfections and non-linearities in the current-to-field relationship. This study proposes methodologies for the control of the magnetic field output of a system comprising 18 coils, subject to the influence of saturated iron. In particular, we integrate current sequence optimization with neural network-based predictions for field and gradient values, thereby enabling the precise and power-optimal generation of magnetic fields. The proposed framework for controlling non-linear magnetic field generators represents a significant advancement in MPI technology, paving the way for the development of human-scale, power-efficient medical imaging solutions.Publicationtype: Journal Article7 8