International Journal on Magnetic Particle Imaging (IJMPI)
Not a member yet
555 research outputs found
Sort by
An End-to-end MPI image reconstruction with dual-task generative adversarial network
No full textTraditional reconstruction methods, such as system matrix and x-space, are either extremely time-consuming or result in very blurry images. Here, we propose a novel dual-task generative method to realize high-quality MPI image reconstruction. In this method, the generative model simultaneously undertakes two MPI image processing tasks: reconstruction and segmentation. The main task of image reconstruction generates MPI images, while the auxiliary task of image segmentation guides the main task to focus on key areas of objects in MPI images during the generation process. Our experimental results showed that the proposed dual-task model, with its superior generalization ability, outperforms both traditional MPI reconstruction methods and single-task generative methods. Our results also suggested that the tasks of image generation and image segmentation significantly promote each other during the MPI image reconstruction
Introduction of a water-resistant stent marking technology for magnetic particle imaging
No full textMagnetic Particle Imaging offers numerous applications in the field of cardiovascular imaging and theguidance of endovascular interventions. In particular, the visualization of vessel and stent lumina is apromising aspect for the detection of in-stent stenosis, for example. For future clinical use, additionalvisualization of the stents themselves would be beneficial, such as for monitoring stent position and the earlydetection of in-stent stenosis. This work investigated a varnish-based stent marking technology using magneticnanoparticles and a sealant coating. The coating demonstrated water resistance for a limited period of time,and the marked stents were successfully visualized
Evaluation of casein coated iron oxide magnetic nanoparticles
No full textTheranostic systems offer a promising approach for early cancer diagnosis and treatment. Here we report the investigation of Na-caseinate-coated iron oxide magnetic nanoparticles (MNP) for potential use in theranostics. The MNP were synthesized in a continuous flow, coated with Na-caseinate, and crosslinked enzymatically for improved stability and drug loading. To evaluate their magnetic suitability for magnetic particle imaging (MPI) and hyperthermia, we conducted DC magnetization measurements, magnetic particle spectroscopy (MPS), and AC-magnetometry. Results show that Na-caseinate coating has minimal impact on magnetic behavior, with a stable magnetization saturation (Ms) of 109(5) A·m²/kg(Fe) for both coated and uncoated particles. The MPI signal (A3*) decreased by less than 15%, with a slight 2% drop in the A5/A3 ratio. Additionally, Na-caseinate coating improved salt stability without altering magnetic performance, supporting their potential for theranostic applications in drug delivery, MPI, and hyperthermia
Background signal suppression using a transformer-based masked autoencoder for magnetic particle imaging
No full textMagnetic particle imaging (MPI), an emerging imaging technique, utilizes the nonlinear response of superparamagnetic iron oxide nanoparticles to generate an image of their spatial distribution. To obtain the high quality MPI images, it is necessary to suppress the background signal. In the previous work, we have proposed a deep learning based method, which can effectively suppress different background signal at different level simultaneously. In this work, we further designed a transformer-based masked autoencoder to learn the relationship between different harmonic components for better noise suppression. The experiments show that the proposed method can effectively suppress background noise at different levels. Besides, our method can reduce the network\u27s dependence and demand on the amount of datasets
Single-harmonic-based narrowband MPI: Effect of different harmonics
No full textSingle-harmonic-based narrowband magnetic particle imaging (MPI) is one of the most promising approaches, which only measures only a single harmonic to visualize the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). In this paper, we investigate the effect of different harmonics, e.g. the 3rd, the 5th and the 7th harmonic, on the spatial resolution of single-harmonic-based narrowband MPI. The point spread functions of different harmonics at an excitation magnetic field of 4 mT and 10 kHz are simulated and evaluated by comparing the full width at half maximum (FWHM). Different harmonics of the 3rd, the 5th, and the 7th harmonics are used to reconstruct MPI images to investigate their effects on the spatial resolution. Simulation results indicates that with increasing harmonic order, the FWHM get narrower and the spatial resolution gets improved
Signal characteristics of the clinically approved tracer Resotran in MPI and MRI
No full textPotential medical applications for Magnetic Particle Imaging (MPI) are diverse. Especially, cardiovascular and cerebral perfusion imaging as well as the monitoring of endovascular interventions are very promising. With the approval of the Ferucarbotran-based tracer Resotran, a big hurdle on the way to clinical MPI has been overcome. A key characteristic of Resotran is the possibility of using it as a bimodal tracer for MPI and MRI. In this work, we tested the signal performance of Resotran in both preclinical MPI and clinical MRI
Power-Efficient Control of Non-Linear Magnetic Field Generators for MPI
No full textThe 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
An 101 kHz – narrowband magnetic particle imaging scanner
No full textMagnetic particle imaging (MPI) is an emerging medical imaging modality for quantitatively visualizing the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). In this study, we develop a narrowband MPI scanner with an excitation frequency of 101 kHz. In x-direction, a solenoid coil is used to generate the 101 kHz ac magnetic field with amplitude of 4 mT for the SPIONs excitation. In y-direction, a saddle coil is used to generate a low-frequency ac magnetic field to scan a field free point. A gradiometric detection coil is used to only measure the 3rd harmonic at 303 kHz for the SPIONs visualization. Phantom experiments are performed with SynomagD-70 SPIONs. It indicates that reconstructed images have a spatial resolution of 1.5 mm and 1 mm for a gradient field of 0.56 T/m and 1.12 T/m in x- and y-direction, respectivel
Extending tuning coil loading for improved passive compensation in multi-frequency MPI towards nominal field strength operation
No full textIn Magnetic Particle Imaging (MPI), minimizing the feedthrough of the excitation signal into the receive signal helps in capturing the fundamental frequency response of the superparamagnetic iron oxide nanoparticle (SPIONs), improving the signal to noise ratio and assisting quantitative measurements. The concept of tuning coils can improve the performance of gradiometer receive coils by inducing suitable signals into the receive coils to reduce the remaining excitation signal without hampering the reception of the particle signal. Adjusting the current in the tuning coils is done by applying loading, controlled via solid state switches. In this work, an arrangement capable for operation at nominal field strength of a multi-frequency MPI (mf-MPI) scanner for mouse sized objects is presented. A high voltage loading board is applied. The adjustment of the load is integrated into an automated control loop
Fundamental Imaging performance of magnetic particle imaging system using high-Tc superconducting coils
No full textWe investigated the fundamental imaging performance of the developed high temperature superconductor (HTS) MPI system with 120 mm bore diameter. The full width at half maximum, which is related to the spatial resolution of the image, was 30 mm under the gradient field of 0.34 T/m. Note that the gradient field can be easily increased by increasing the number of turns of the HTS selection field coils since the power consumption and the mass of the HTS coils are very low. We also obtained the reasonable limit of detection as 48 micro-g(Fe). Since the power consumption and the mass of MPI scanner can be dramatically reduced by using HTS tape compared with those made of Cu wire, a HTS MPI scanner is one of the promising candidates for the realization of human-body-sized MPI scanner