Fig. 1

Representation of the K-edge energies and thresholds (dotted lines) used for the characterisation of each element. x-ray mass attenuations of iodine (purple) and gadolinium (green) (a), as well as gold (yellow) and gadolinium (green) (b) are shown with solid lines. c, d Eleven tubes of mixed contrast agents were prepared. The solutions were organised in a spiral, such that contrast agent 1 (in blue) was prepared at a decreasing concentration while contrast agent 2 (in red) was prepared at an increasing concentration. The tubes in the phantom have the same colour on the schema because of their same-targeted CT attenuation values (~ 280 HU)