Reply #7: That stuff's about the most inert sort of thing ever placed in your body

[Posteritatis]

That's why they use it for x-rays and the like - it's opaque to x-rays, non-toxic, and so phenomonenally useless to your body that it just goes "who put this here? Get rid of it!" and proceeds to do so easily without absorbing any of it. It's like non-stuff as far as your body's concerned.

If they injected something into you, that was most likely iodine-based and also safe as houses for anything near the time you'd have it in your system.