Pu-239
The Half Life of Timofey Berezin (2006)
It was described to me as Traffic with plutonium, and that's kind of accurate.
Many elements were in place for a compelling movie experience; in medias res, the built-in countdown, the sense of larger institutional forces pitted against one man ...
but the story stumbled a bit, primarily because the characters acted in ways counter to their interests and desires.
where it succeeded was in the political and medical arenas. the story of Berezin's mission had a backdrop of scheming sovereign powers, and as his case of acute radiation poisoning advances, we learn all about how dangerous his corpse will become, and remain.
Paddy Considine did a stellar job, but don't get me started on the accents.
uhlume asked a good question, though: what would insufflating Pu-239 feel like? I conjectured that it would be initially like nothing (plutonium is metal), then one would feel a mild burning sensation that would get worse.