Targeted Silver Nanoparticles for Dual-Energy Breast X-Ray Imaging

Silver nanoaprticles have been investigated as an alternative to iodinein dual-energy breast x-ray imaging. Dual-energy imaging involves acquiringimages at two distinct energy windows (low and high). Weighting factors arethen applied to create an image where the contrast between background tissueshas been suppressed. Silver (Ag) represents an attractive contrast material dueto its favorable x-ray attenuation properties (k-edge of 25.5 keV). Theoreticalanalysis using polychromatic spectra shows that silver can provide similar, ifnot better, contrast to iodine. Spherical Ag nanoparticles with an average diam-eter of 4 ±2 nm were synthesized using the Brust method in water. The parti-cles were surface stabilized with polyethylene glycol and showed little cellulartoxicity in T6-17 fibroblast cells. These results have encouraged further inves-tigation into validation and testing in living system models. Silver nanoparti-cles represent an exciting avenue for the development of a novel dual-energy, x-ray breast imaging agent.