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In assessing the safety aspect of future clinical magnetic particle imaging (MPI), this novel imaging technique can refer to expertise that is cumulated in the IEC standard for magnetic resonance imaging (MRI) safety. Both imaging techniques employ strong dynamic magnetic fields and therefore have to take caution to refrain from physiological effects such as peripheral nerve stimulation (PNS) or excessive tissue heating. This paper starts with an outline of the differences between MPI and MRI. Then, the basics of PNS and tissue heating are reviewed and applied to the specific MPI case. Finally, sequences for MPI are presented that will allow rapid MPI imaging at 150 kHz while being safe for the patient. Index Terms-Magnetic particle imaging (MPI), magnetic stimulation, peripheral nerve stimulation (PNS), specific absorption rate (SAR).

After realizing the worlds' first preclinical magnetic particle imaging (MPI) demonstrator, Philips is now realizing the worlds' first whole-body clinical prototype to prove the feasibility of MPI for clinical imaging. After a brief introduction of the basic MPI imaging process, this contribution presents an overview on the determining factors for key properties, i.e., spatial resolution, acquisition speed, sensitivity, and quantitativeness, and how these properties are influenced by scaling up from preclinical to clinical instrumentation. Furthermore, it is discussed how this scale up affects the physiological compatibility of the method as well as hardware parameters such as power requirements for drive field generation, selection and focus field generation, and the design of the receive chain of the MPI device.

Magnetic Particle Imaging (MPI) is a high-potential new medical imaging modality that has been introduced in 2005.MPI uses the non-linear magnetization behavior of iron-oxide based nano-particles, named tracer, to perform quantitative measurements of their local concentration. Previous publications demonstrated the feasibility of real-time in vivo 3D imaging with clinical concentration of Resovist®. Given MPI's fast and sensitive imaging as well as its overall versatility, it has potential to support various medical applications spanning from diagnostics to therapy. As an example, ongoing research investigates the use of MPI in cardiovascular diagnostics for myocardial perfusion measurement.While previous publications reported results from experimental systems with limited bore size (3cm), this contribution presents first phantom and in vivo images acquired on the next hardware generation, an experimental system with an effective bore size of 12cm. The system is designed for pre-clinical studies and can capture image data from an extended field of view compared to the previous, experimental system. The contribution introduces concepts for the encoding of a larger field of view by means of additional magnetic fields, named focus-fields, and outlines the path to stitching of images from multiple focus field settings, called "multi-station reconstruction". To prove the feasibility of imaging of an extended field of view, volumetric images of a moving phantom as well as of a living rat were acquired.