Nanophosphor-Based Contrast Agents for Spectral X-ray Imaging

• Published in: Nanomaterials (Basel, Switzerland) Vol. 9; no. 8; p. 1092
• Main Authors: Smith, Kevin, Getzin, Matthew, Garfield, Josephine J, Suvarnapathaki, Sanika, Camci-Unal, Gulden, Wang, Ge, Gkikas, Manos
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.07.2019; MDPI
• Subjects: Acids; Acrylic acid; Aqueous solutions; Cancer; Computed tomography; Contrast agents; Correlation analysis; CT imaging; Density; Diagnostic systems; Dispersion; Drug dosages; Engineering; Exchanging; Fluorides; Image acquisition; Image enhancement; Image processing; Iodine; lanthanide nanoparticles; Ligands; Macromolecules; Medical imaging; Medical screening; Nanoparticles; Nanophosphors; Oleic acid; Organic chemistry; Polymers; Quantum dots; rare earth metals; Signal processing; Spectra; spectral CT; Tumors; X ray imagery; X-ray contrast agents; X-rays; United States > US; Massachusetts; computed tomography; CT imaging; lanthanide nanoparticles; nanophosphors; spectral CT; X-ray contrast agents; rare earth metals
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano9081092

Lanthanide-based nanophosphors (NPhs) are herein developed as contrast agents for spectral X-ray imaging, highlighting the chemical, macromolecular and structural differences derived from ligand exchange on computed tomography (CT) and solvent dispersibility. Taking advantage of the ability of spectral X-ray imaging with photon-counting detectors to perform image acquisition, analysis, and processing at different energy windows (bins), enhanced signal of our K-edge materials was derived, improving sensitivity of CT imaging, and differentiation between water, tumor-mimic phantoms, and contrast materials. Our results indicate that the most effective of our oleic acid-stabilized K-edge nanoparticles can achieve 2-4x higher contrast than the examined iodinated molecules, making them suitable for deep tissue imaging of tissues or tumors. On the other hand, ligand exchange yielding poly(acrylic acid)-stabilized K-edge nanoparticles allows for high dispersibility and homogeneity in water, but with a lower contrast due to the high density of the polymer grafted, unless further engineering is probed. This is the first well-defined study that manages to correlate NPh grafting density with CT numbers and water dispersibility, laying the groundwork for the development of the next generation CT-guided diagnostic and/or theranostic materials.