Size and Concentration Effect of Gold Nanoparticles on X-ray Attenuation As Measured on Computed Tomography

We study size and concentration effect of Au nanoparticles on the attenuation to X-ray used for computed tomography. By investigating size (4, 20, 38, and 60 nm) and concentration (up to 1 mg/ml) effect of GNPs, we demonstrate that GNPs are nontoxic to HeLa S3 cells and the smaller GNPs show greater X-ray attenuation than the larger ones. The X-ray attenuation of GNPs over the iodine-based contrast agent, Omnipaque, is much enhanced at higher concentration.