I'm no biology expert, but taking a drug that is radioactive and also potentially disrupts/elevates potassium blood levels does not sound like a good idea.
One experimental study doesn't demonstrate safety.
If you actually read that paper, the scientists had much difficulty even finding a doctor willing to prescribe it to the study patients, and the study was quickly discontinued due to the side effects (which do not sound pleasant; agitation, anxiety, bradycardia, skin rashes, diarrhea, etc) . Combined with its very long half life, toxicity from repeat dosing was a huge concern.
Interesting, though.