An examination of silver as a radiographic contrast agent in dual-energy breast x-ray imaging

Abstract

Silver nanoaprticles have been investigated as an alternative to iodine in dual-energy breast x-ray imaging. Dual-energy imaging involves acquiring images at two distinct energy windows (low and high). Weighting factors are then applied to create an image where the contrast between background tissues has been suppressed. Silver (Ag) represents an attractive contrast material due to its favorable x-ray attenuation properties (k-edge of 25.5 keV). Theoretical analysis using polychromatic spectra shows that silver can provide similar, if not better, contrast to iodine. Spherical Ag nanoparticles with an average diameter of 4 ±2 nm were synthesized using the Brust method in water. The particles were surface stabilized with polyethylene glycol and showed little cellular toxicity in T6-17 fibroblast cells. These results have encouraged further investigation into validation and testing in living system models. Silver nanoparticles represent an exciting avenue for the development of a novel dual-energy, x-ray breast imaging agent. © 2012 Springer-Verlag Berlin Heidelberg.