Berlin 2008 – wissenschaftliches Programm

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ST: Fachverband Strahlen- und Medizinphysik

ST 2: Medical Physics: Magnetic Resonance, Ultrasound, Dosimetry

ST 2.2: Vortrag

Montag, 25. Februar 2008, 13:30–13:45, H 2033

Influence of Ultrasound on Magnetic Resonance Imaging Contrast Agents (SPIO) — •Nouri Elmiladi, Christian Höhl, Jessica Mende, Maurice Schlichtenmayer, Bernd Habenstein, and Karl Maier — Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany

Magnetic resonance imaging (MRI) is one of the most powerful imaging techniques for living organisms. Magnetic nanoparticles such as superparamagnetic iron oxide (SPIO) have been applied as contrast enhancement agents for MRI. We develop a new contrast method for SPIO with the application of ultrasound (US) while performing proton magnetic resonance spectroscopy. Especially prepared SPIO should work as radio frequency transmitters. The nanoparticles are prepared such that the center of geometry differs from the center of mass. This is done by the magnetic oriented sedimentation of the SPIOs so that we can add macromolecules from one side only. Sedimentation process of the SPIO have been achieved by applying a combination of centrifugal force and magnetic force. Due to the particle velocity in the resonant US wave, SPIOs are accelerated and due to their asymmetric shape, they tilt periodically. This produces additional photons with the US frequency that affect the relaxation times. Using nanopariticles as local antenna in combination with US promises new contrast methods to visualize additional properties of the tissue. Even without any special preparation of the nanoparticles, an effect of the US on the MRI signal has already been seen.