New imaging procedure without radiation exposure
A team of physicists and doctors from the University of Würzburg has developed a mobile scanner for endovascular interventions that does not require ionising radiation or nephrotoxic contrast media. The scanner is based on radiation-free imaging diagnostics called "Magnetic Particle Imaging" (MPI), which uses magnetic fields in combination with magnetic nanoparticle tracers for visualisation.
The new portable interventional MPI scanner (iMPI) uses magnetic fields to determine the spatial distribution of tracers made of magnetic nanoparticles. These are injected in advance as markers. After that, external magnetic fields manipulate the magnetisation of the nanoparticles, which makes it possible to detect their position in the human body.
MPI as a diagnostic imaging technique is not newPrevious MPI scanners were too large, expensive and had a small viewshed of a few centimetres. The first human-sized MPI scanner had limitations in terms of acquisition time, portability and gradient strength. The latter is essential for high spatial resolution, but also causes high power consumption and a rise in temperature.
Within the framework of a research project funded by the German Research Foundation, these barriers could be overcome. The developed iMPI scanner has a gradient strength of about 0.36 tesla per metre with a power consumption of 14 kilowatts, which allows a spatial resolution of about 5 millimetres. To get an idea of the temperature rise of the iMPI scanner, the physicists estimate a temperature rise per image of 0.18 Kelvin.