[24] examined 203 patients within 3 months of 131 I therapy (100-200 mCi ... when the patient's history of having received radioactive iodine is factored into the patient's clinical symptomatology.

On raiding it, they found 13 playing cards laced with iodine-125, a substance used in medicine that has a half-life of 60 days. That means it stays radioactive for longer than most other types of ...

Gunther, R. L., and Jones, H. B., U.S. Atomic Energy Commission Document No. UCRL-2689 (1954). Comar, C. L., Trum, B. F., and Kuhn, U. S. G., Science, 126, 16 (1957).

In the event of a nuclear catastrophe, taking iodine can help to protect against some types of radiation exposure. During a such an event, radioactive iodine can be released into the environment.