Matthias Gräser | Searcharxiv

arXiv2023

In situ theranostic platform uniting highly localized magnetic fluid hyperthermia, magnetic particle imaging, and thermometry in 3D

In all of medical profession a broad field of research is dedicated to seek less invasive and low-risk forms of therapy with the ultimate goal of non-invasive therapy, particularly in neoplasmic diseases. Theranostic platforms, combining diagnostic and therapeutic approaches within one system, have thus garnered interest to augment invasive surgical, chemical, and ionizing interventions. Magnetic particle imaging (MPI) offers, with its versatile tracer material (superparamagnetic iron oxide nanoparticles, SPIOs), a quite recent alternative to established radiation based diagnostic modalities. In addition, MPI lends a bimodal theranostic frame allowing to combine tomographic imaging with therapy techniques using the very same SPIOs. In this work, we show for the first time the interleaved combination of MPI-based imaging, therapy (highly localized magnetic fluid hyperthermia) and therapy safety control (MPI-based thermometry) within one theranostic platform in all three spatial dimensions.

physics.med-ph↗

arXiv2017

Towards Picogram Detection of Superparamagnetic Iron-Oxide Particles Using a Gradiometric Receive Coil

Superparamagnetic iron-oxide nanoparticles can be used in a variety of medical applications like vascular or targeted imaging. Magnetic particle imaging (MPI) is a promising tomographic imaging technique that allows visualizing the 3D nanoparticle distribution concentration in a non-invasive manner. The two main strengths of MPI are high temporal resolution and high sensitivity. While the first has been proven in the assessment of dynamic processes like cardiac imaging, it is unknown how far the detection limit of MPI can be lowered. Within this work, we will present a highly sensitive gradiometric receive-coil unit combined with a noise-matching network tailored for the measurement of mice. The setup is capable of detecting 5 ng of iron in vitro at 2.14 sec acquisition time. In terms of iron concentration we are able to detect 156 μg/L marking the lowest value that has been reported for an MPI scanner so far. In vivo MPI mouse images of a 512 ng bolus at 21.5 ms acquisition time allow for capturing the flow of an intravenously injected tracer through the heart of a mouse. Since it has been rather difficult to compare detection limits across MPI publications we propose guidelines improving the comparability of future MPI studies.

physics.med-ph↗