Blood Clearance of Dextran Magnetite Particles Determined by a noninvasive in vivo ESR method

Abstract

Dextran magnetite (DM) is a potential MR contrast agent with superparmagnetic properties. Its fast clearance from the blood and selective uptake by tissue macrophages provide advantages for imaging tumors in the liver and spleen. DM consists of a suspension of solid particles with a wide distribution of sizes, In this study we have used ESR spectroscopy to determine the blood clearance of DM injected iv mice. The spectra are obtained on living animals by inserting the tail of a mice into the waveguide cavity of the ESR spectrometer and recording the ESR spectrum continously. This procedure allows the direct measurement of the plasma clearance of DM from individual animals, without blood sampling. We applied this method to study the clearance of suspensions of DM particles with different averge sizes. © 1991 Academic Press, Inc.