Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
ST: Fachverband Strahlen- und Medizinphysik
ST 2: Medical Physics: Magnetic Resonance, Ultrasound, Dosimetry
ST 2.3: Vortrag
Montag, 25. Februar 2008, 13:45–14:00, H 2033
Influencing the Relaxation Times of Proton NMR with Resonant Ultrasound and Piezoceramic Nanoparticles — •Jessica Mende, Nouri Elmiladi, Christian Höhl, and Karl Maier — Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14-16, 53115 Bonn, Germany
In magnetic resonance imaging, nanometer-sized colloidal particles (nanoparticles) have been widely used as contrast agents for clearer and more specific images and to localize specific organs. We investigate the influence of piezoelectric nanoparticles on the relaxation times of proton magnetic resonance spectroscopy (1H-MRS) and 1H-MRS in combination with resonant ultrasound (US).
A piezoceramic powder consisting of 100 nm sized particles was prepared into a colloid in water by coating with polyacrylic acid. Measurements have shown that the nanoparticles have an influence on the spin-lattice relaxation time T1 of water, which elongates by about 1%. Piezoelectric particles have the ability to generate an electric potential in response to directed mechanical stress. In combination with the periodic pressure variation in a resonant US-wave, these particles function as an emitter for electromagnetic fields with US frequency and couple to the spin-system. The influence of the piezoelectric particles on 1H-MRS is discussed.