Sometime back I had copied some info relating to nuclear emergencies to a word file. I don't remember where it came from, so I'd recommend that you do your homework before even thinking about trusting the info, but here it is anyway as a starting point for your own investigation.
"In an emergency, if no more KI tablets available, you can topically (on the skin) apply an iodine solution, like tincture of iodine or Betadine, for a similar protective effect. (WARNING: Iodine is NEVER to be ingested or swallowed, it is poison to drink.) For adults, paint 8 ml of a 2 percent tincture of Iodine on the abdomen or forearm each day, ideally at least 2 hours prior to initial exposure. For children 3 to 18, but under 150 pounds, only half that amount painted on daily, or 4 ml. For children under 3 but older than a month, half again, or 2 ml. For newborns to 1 month old, half it again, or just 1 ml. (One measuring teaspoon is about 5 ml, if you don't have a medicine dropper graduated in ml.) If your iodine solution is stronger than 2%, reduce the dosage accordingly. Absorption through the skin is not as reliable a dosing method as using the tablets, but tests show that it will still be very effective for most."
We have a reactor that we would be 125 miles downwind of during a normal summer air pattern, so I have KI pills stocked up. As a last resort though, I might be willing to try the above, if only to see us through a bugout.