Rice University scientists have invented a better X-ray for soft tissues.

They propose to fill carbon nanotubes with iodine, coat them with a film of protein that bonds with specific types of cell, and allow the tubes to become embedded in the cells of interest.

As well as giving a greater choice of targets for analysis, this should allow images to be taken over a longer periods of time because the nanotubes are buried in situ rather than only passing through in the blood.