Second generation gold nanobeacons for robust K-edge imaging with multi-energy CT

Abstract

Spectral CT is the newest advancement in CT imaging technology, which enhances traditional CT images with it’s the capability to image and quantify certain elements based on their distinctive K-edge energies. The K-edge imaging feature recognizes high accumulations of targeted elements and presents them as colorized voxels against the normal grayscale X-ray background offering promise to overcome the relatively low inherent contrast within soft tissue and distinguish the high attenuation of calcium from contrast enhanced targets. Towards this aim, second generation gold nanobeacons (GNB₂), which incorporate at least five times more metal than the previous generation, were developed. The particles were synthesized as lipid-encapsulated, vascularly constrained (>120 nm) nanoparticles incorporating tiny gold nanoparticles (2–4 nm) within a polysorbate core. The choice of core material dictated the achievement of a higher metal loading. The particles were thoroughly characterized by physico-chemical techniques. This study reports one of the earlier examples of spectral CT imaging with gold nanoparticles demonstrating the potential for targeted in vitro and in vivo imaging and eliminates calcium interference with CT. The use of statistical image reconstruction shows that high SNR may allow dose reduction and/or faster scan times.