Regensburg 2013 – wissenschaftliches Programm

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SYBD: Symposium Magnetic Nanoparticles in Biomedical Diagnostics and Therapy

SYBD 1: Magnetic Nanoparticles in Biomedical Diagnostics and Therapy

SYBD 1.3: Hauptvortrag

Montag, 11. März 2013, 16:00–16:30, H1

Magnetic Particle Imaging: A new Medical Imaging Modality — •Thorsten Buzug — Institute of Medical Engineering, University of Lübeck, Germany

Recently, magnetic particle imaging (MPI) has been introduced as a novel method for direct measurement of the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIOs) that are used as tracer material. The SPIOs are subjected to a sinusoidally oscillating magnetic field and respond with a nonlinear change in magnetization. The acquired induction signal contains harmonics of the fundamental excitation frequency, which are subsequently used for determination of the spatial particle distribution and concentration. For spatial encoding a magnetic gradient field (the selection field) is superimposed onto the sinusoidal excitation field (the drive field) such that a field-free point (FFP) is established at a desired location within the field of view. Nanoparticles located near the FFP contribute to the signal generation, whereas particles that are far from the FFP are in saturation and cannot contribute. Image reconstruction from the measured induction signals can be seen as the solution for the corresponding inverse problem. In this talk, the state of the art in magnetic coil design for MPI is discussed. With a new symmetrical arrangement of coils, a field-free line can be produced that promises a significantly higher sensitivity compared with the standard arrangement for an FFP. Additionally, an alternative single-sided coil assembly is presented for the use in hand-held applications.