The University and University Hospital of Würzburg have demonstrated magnetic particle imaging on humans for the first time. The new procedure enables radiation-free visualisation of blood vessels in real time.
131 years ago, the physicist Wilhelm Conrad Röntgen discovered the rays named after him in Würzburg, enabling completely new methods for visualising the human body. Now an interdisciplinary team of physicists and radiologists in Würzburg has achieved another important milestone in medical imaging. The researchers have demonstrated a new type of technology on humans for the first time: magnetic particle imaging (MPI).
While Röntgen photographed his wife Bertha’s hand in December 1895, physicist Dr Patrick Vogel, who works at the Chair of Experimental Physics 5 at Julius-Maximilians-Universität Würzburg (JMU), held his arm in the MPI scanner as a healthy test person. Vogel played a key role in the development of this technology and conducted the experiment together with Dr Viktor Hartung from the Institute of Diagnostic and Interventional Radiology at the University Hospital of Würzburg (UKW).
"When you test a new imaging technique on humans for the first time, you naturally want to find out for yourself what it feels like. It was therefore only natural for me to be available as the first test person," reports Patrick Vogel.
MPI: Imaging with magnetic nanoparticles
MPI belongs to a new generation of imaging techniques. Instead of X-rays or radioactive tracers, MPI uses tiny magnetic iron oxide nanoparticles as a contrast agent. These are injected into the bloodstream and then detected using magnetic fields.
The special thing about this is that MPI only detects the nanoparticles themselves; the surrounding tissue does not generate a background signal. This results in particularly high-contrast images with high temporal resolution. At the same time, the method works completely without ionising radiation.
Milestone after almost 20 years of development
With the first application of MPI on humans, the technology has reached an important milestone in its development history. The teams in Würzburg have been working on the development of magnetic particle imaging for around 20 years - from the first physical concepts to the construction of experimental scanners and the integration of the technology into a clinical environment.
"The fact that we have now been able to demonstrate this technology in humans for the first time is a decisive step on the way to the clinical application of magnetic particle imaging," comments Patrick Vogel on the start of the translational development phase. "This shows that MPI not only works in the laboratory, but can also be used under real clinical conditions."
First MPI angiography in humans for vascular visualisation on the arm
As part of the study, the researchers performed vascular imaging on the arm. To do this, they injected clinically approved iron oxide nanoparticles and recorded their distribution using a specially developed MPI scanner.
For direct comparison, they also performed digital subtraction angiography (DSA), the current standard method for visualising blood vessels using X-rays.
The results show: MPI was able to visualise the most important superficial and deep veins of the arm, including their branches. The image rate was two images per second and thus in the range of clinical angiography procedures.
New possibilities for interventions - without radiation exposure
"The images show that we can visualise the relevant vascular structures and blood flow in real time," explains radiologist Viktor Hartung. "This opens up the prospect of new possibilities for interventional procedures - without radiation exposure." However, further preclinical and clinical studies are required to systematically analyse the safety, effectiveness and clinical benefits.
From a clinical perspective, magnetic particle imaging has great potential, according to Professor Thorsten Bley. The Director of the Institute of Diagnostic and Interventional Radiology at the UKW emphasises: "If it is possible to image vessels in real time without ionising radiation, this could open up new possibilities for interventional procedures in the long term."
Close collaboration between physics and clinical medicine
It was possible to conduct this study thanks to the close collaboration between physics and medicine. While the physical principles and scanner technologies are developed in experimental physics, radiology contributes its experience in clinical imaging and interventional procedures.
"Such developments can only be achieved through close collaboration between basic research and clinical application," says Professor Volker Behr , head of the MPI working group at the Chair of Experimental Physics 5 (Biophysics) at JMU. "Our aim is to further develop new physical concepts in such a way that they offer real added value for medical diagnostics and therapy in the long term."
South German Centre for Magnetic Particle Imaging (SMPI)
The application in humans is part of a larger research strategy at the University of Würzburg. The establishment of a South German Centre for Magnetic Particle Imaging (SMPI) at JMU was recently approved and is funded by the German Research Foundation (DFG). The centre, headed by Volker Behr, will create an infrastructure to further develop MPI from basic research to medical applications.
Preprint
The publication is currently in the scientific peer review process. A preprint is available at the following URL: https://doi.org/10.48550/arXiv.2603.12010
Note for patients and interested parties
The results described here are based on an early feasibility demonstration in humans. The technology is only just entering the translational development phase and is not currently intended for routine clinical use, patient treatment or therapeutic decisions. Further preclinical and clinical studies are required to systematically analyse safety, efficacy and clinical benefit.
