Diamonds engage both optical microscopy and MRI for better imaging

The microdiamonds used as biological tracers are about 200 microns across, less than one-hundredth of an inch. They fluoresce red but can also be hyperpolarized, allowing them to be detected both optically - by fluorescence microscopy - and by radio-frequency NMR imaging, boosting the power of both techniques. (Photo courtesy of Ashok Ajoy) When doctors or scientists want to peer into living tissue, there's always a trade-off between how deep they can probe and how clear a picture they can get. With light microscopes, researchers can see submicron-resolution structures inside cells or tissue, but only as deep as the millimeter or so that light can penetrate without scattering. Magnetic resonance imaging (MRI) uses radio frequencies that can reach everywhere in the body, but the technique provides low resolution - about a millimeter, or 1,000 times worse than light. A University of California, Berkeley, researcher has now shown that microscopic diamond tracers can provide information via MRI and optical fluorescence simultaneously, potentially allowing scientists to get high-quality images up to a centimeter below the surface of tissue, 10 times deeper than light alone. By using two modes of observation, the technique also could allow faster imaging.