13 research outputs found
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)
No full textCorrection 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
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)
No full textCorrection 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.3
Spatial encoding with receive coils in MPI
No full textMPI techniques traditionally use gradient magnetic fields for spatial encoding. Despite their proven efficiency, these methods are power-intensive and technically challenging to implement on a human scale. In this work, we explore the potential for spatial encoding of superparamagnetic nanoparticle distributions using only a drive field and an array of receiving coils with unique spatial sensitivity profiles. We demonstrate the feasibility of this concept using a prototype 1D imaging system extended to 2D by mechanically moving the sample. The proposed approach permits high-speed gradient-free data acquisition for rapid imaging but also has some limitations in terms of penetration depth
Power-optimized drive field coils for human brain magnetic particle imaging
No full textThe implementation of human-scale magnetic particle imaging is significantly restricted by the nonlinear growth in power with the size of the field-generating coils. To address this issue, we developed anatomically optimized shapes with a reduced internal volume for the head drive field system using a wide range of anatomical data as a reference. On the base of designed complex bodies, we synthesized windings for two orthogonal coils with the help of the stream functions approach. The resulting coil set was compared to the state-of-the-art solenoid/saddle coil pair and showed a reduction in power consumption by a factor of 1.58 in numerical simulations. We also built a prototype of the designed coils using additive manufacturing and used it to receive the first signals from the nanoparticles
Design and safety considerations of I/O modules
No full textIn Magnetic Particle Imaging, numerous data inputs and outputs are required to receive and process signalsfrom the feedback and receive coils, and to control the output associated with the drive and selection field coils.Previously used conventional input/output (I/O) boards have shown limitations in regard to the initial start-upprocedures, safety assurance and usability. In order to address these issues, a more sophisticated I=O-Unitwas designed, incorporating and expanding the functionality of twelve measurement cards. These cards arehoused within the I=O-Unit as shielded, interchangeable modules and built up as synchronised multi channelI/O system
Design and Optimization of a Selection Field Generator for a Human-Sized Magnetic Particle Imaging Head Scanner
No full textMagnetic particle imaging (MPI) is currently on the verge of moving from a pre-clinical to a clinical imaging method. In 2019, the first version of a head-scanner and its selection field generator was shown by Graeser et al.. An improvement of the two-coil selection field generator was introduced by Foerger et al., containing 18 iron core coils that can be driven separately. The resulting 9 coils per side are arranged in a 3 x 3 square shape. In this work, this concept is adapted to a human sized scanner examining a set of parameters, including the coil and core size, their material, the current distribution and a division into multiple coils. The setup is simulated in COMSOL 6.1 and optimized with the aim of achieving the target gradient of 0.5 T/m, while minimizing the average power consumption. However, while analyzing the parameters the coil arrangement showed a very promising result in terms of a significant reduction in dissipated power. A MATLAB optimization algorithm, that solves the inverse problem for an optimal current combination for a given target field, reflects the estimated power for each FFP position in the field of view. From this solution a power map can be generated. With this the original sqare- and a new circular arrangement are compared and a reduction of almost half the power consumption can be seen. However, this circular design needs further optimization regarding constructive challenges, but it shows how power-saving selection field generators could look like in the future
Interpersonal and affective dimensions of psychopathic traits in adolescents : development and validation of a self-report instrument
No full textWe report the development and psychometric evaluations of a self-report instrument designed to screen for psychopathic traits among mainstream community adolescents. Tests of item functioning were initially conducted with 26 adolescents. In a second study the new instrument was administered to 150 high school adolescents, 73 of who had school records of suspension for antisocial behavior. Exploratory factor analysis yielded a 4-factor structure (Impulsivity α = .73, Self-Centredness α = .70, Callous-Unemotional α = .69, and Manipulativeness α = .83). In a third study involving 328 high school adolescents, 130 with records of suspension for antisocial behaviour, competing measurement models were evaluated using confirmatory factor analysis. The superiority of a first-order model represented by four correlated factors that was invariant across gender and age was confirmed. The findings provide researchers and clinicians with a psychometrically strong, self-report instrument and a greater understanding of psychopathic traits in mainstream adolescents
Towards industrial production: An additive approach for magnetic particle spectrometers
No full textMagnetic particle spectroscopy is an innovative method for characterizing magnetic nanoparticles with potentialmedical applications. Traditional methods for instrumentation face challenges such as labor-intensive coilmanufacturing, high costs, high tolerances and setup time. This study introduces a new approach using additivemanufacturing to create rectangular nested coils, enhancing performance and reducing production complexity.The coils, printed with conductive and dielectric inks, allow for modular configurations and improved sensitivity.Results demonstrate a sufficient signal-to-noise ratio and effective cancellation of excitation frequencies. Thispresented technique addresses issues of fine-tuning and manufacturing discrepancies while enabling modular andflexible setups tailored to researchers’ specific needs
Thermal Considerations Towards a Highly Flexible Multi-Core Selection and Focus Field Generator
No full textThis paper presents interim results in the development and implementation of a selection and focus field generator for Magnetic Particle Imaging. The construction of a multi-coil field generator specifically designed for the purpose of diffusion imaging of the brain is a complex task. The degrees of freedom in topological decisions with interconnected dependencies require careful considerations. The preliminary results of the initial constructional and electrical concept based on simulations are presented.A focus in decision making was placed on the manufacturability of the coils and their thermal properties. The conducted experiments indicate that the manufacturing and fixation of the core coil module presents a significant challenge. Additionally, more advanced cooling strategies have been pre-evaluated, as the intended cooling setup has been found to be inadequate in the visualized setup
Transcript-dependent effects of the CALCA gene on the progression of post-traumatic osteoarthritis in mice
No full textOsteoarthritis represents a chronic degenerative joint disease with exceptional clinical relevance.Polymorphisms of the CALCA gene, giving rise to either a procalcitonin/calcitonin (PCT/CT) or acalcitonin gene-related peptide alpha (αCGRP) transcript by alternative splicing, were reported to beassociated with the development of osteoarthritis. The objective of this study was to investigate therole of both PCT/CT and αCGRP transcripts in a mouse model of post-traumatic osteoarthritis (ptOA).WT, αCGRP−/− and CALCA−/− mice were subjected to anterior cruciate ligament transection (ACLT) toinduce ptOA of the knee. Mice were sacrificed 4 and 8 weeks post-surgery, followed by micro-CT andhistological evaluation. Here we show that the expression of both PCT/CT and αCGRP transcripts isinduced in ptOA knees. CALCA−/− mice show increased cartilage degeneration and subchondral boneloss with elevated osteoclast numbers compared to αCGRP−/− and WT mice. Osteophyte formation isreduced to the same extent in CALCA−/− and αCGRP−/− mice compared to WT controls, while areduced synovitis score is noticed exclusively in mice lacking CALCA. Our data show that expressionof the PCT/CT transcript protects from the progression of ptOA, while αCGRP promotes osteophyteformation, suggesting that CALCA-encoded peptides may represent novel targets for the treatmentof ptOA.Osteoarthritis represents a chronic degenerative joint disease with exceptional clinical relevance. Polymorphisms of the CALCA gene, giving rise to either a procalcitonin/calcitonin (PCT/CT) or a calcitonin gene-related peptide alpha (αCGRP) transcript by alternative splicing, were reported to be associated with the development of osteoarthritis. The objective of this study was to investigate the role of both PCT/CT and αCGRP transcripts in a mouse model of post-traumatic osteoarthritis (ptOA). WT, αCGRP−/− and CALCA−/− mice were subjected to anterior cruciate ligament transection (ACLT) to induce ptOA of the knee. Mice were sacrificed 4 and 8 weeks post-surgery, followed by micro-CT and histological evaluation. Here we show that the expression of both PCT/CT and αCGRP transcripts is induced in ptOA knees. CALCA−/− mice show increased cartilage degeneration and subchondral bone loss with elevated osteoclast numbers compared to αCGRP−/− and WT mice. Osteophyte formation is reduced to the same extent in CALCA−/− and αCGRP−/− mice compared to WT controls, while a reduced synovitis score is noticed exclusively in mice lacking CALCA. Our data show that expression of the PCT/CT transcript protects from the progression of ptOA, while αCGRP promotes osteophyte formation, suggesting that CALCA-encoded peptides may represent novel targets for the treatment of ptOA.</p
