| 摘要 |
<p>Image-enhancing agent comprising a biodegradable, water-soluble polymer, synthetic or naturally derived and having repeating hydrophilic monomeric units with amino or hydroxyl groups. This agent also includes chelating agents comprising functional groups bound to an amino or hydroxyl group of the monomeric units. These chelating agents have a formation constant for divalent or trivalent metal cations of at least about 108 at physiological temperature and pH. This image-enhancing agent is biodegradable to intermediary metabolites, excretable chelates, oligomers, monomers or combinations thereof of low toxicity. These image-enhancing agents may further comprise a paramagnetic metal ion for enhacement of the image arising from induced magnetic resonance signals. Images resulting from scanning of gamma particle emissions may be enhanced when the image-enhancing agent of the present invention comprises radioisotopic metal ions emitting gamma particles. The physical conversion of these image-enhancing agents into microspheres (or, less optimally, microaggregates) allows further internal directioning of the image-enhancing agents to organs with phagocytic capabilities. Dextran is a preferred polymer; DTPA and gadolinium are respectively preferred chelating agents and paramagnetic metal ions.</p> |
