Abstract: Various embodiments of the present invention pertain to x-ray absorbing compositions that comprise a carbon material associated with an x-ray absorbing material. In some embodiments, the x-ray absorbing material is selected from the group consisting of lead-based compounds, bismuth-based compounds, and combinations thereof. In some embodiments, the carbon material is selected from the group consisting of carbon nanotubes, graphenes, carbon fibers, amorphous carbons, and combinations thereof. In further embodiments, the carbon materials of the present invention may also be treated with a surfactant, an acid, polymers or combinations thereof. In some embodiments, the carbon materials of the present invention may be further associated with a metal oxide. Additional embodiments of the present invention pertain to methods of making the aforementioned x-ray absorbing compositions. Such methods generally include associating a carbon material with an x-ray absorbing material.