Answer to Question #2659 Submitted to "Ask the Experts"

Q

I have a 13-year-old cat that will be going in for iodine treatment. I am starting the seventh month in my pregnancy as well. I spoke with my doctor already, but I just want to get a second opinion to be sure. I will be following the rules to not be around my cat after treatment; however, actually how risky is this for my unborn baby? How long do I have to be careful around my cat before it is safe again? The facility will be keeping my cat for two weeks because I am pregnant, but is that still okay for my baby?

A

You did not tell me what rules the nuclear medicine personnel intend to have you follow. In two weeks there should be very little radioactive iodine remaining in the excrement of the cat (urine and feces) even if the cat received several millicuries of ¹³¹I. You did not tell me what activity of radioactive iodine will be administered to the cat. If the cat is kept at the kennel for two weeks, there should be few issues with it coming home. A seven-month fetus' thyroid will absorb and concentrate iodine circulating in your body, so you want to minimize any exposure because of your contact with the cat's secretions or excrement. If your cat is an indoor cat, have someone else change the litter pan for an extra four weeks if possible or, if you have to do it, wear gloves. However, you do not have to worry about odor from the litter pan. It will not expose you to radiation so it would have no affect on your baby. Also, handle the cat with gloves for an extra month after you bring it home. Radioactive iodine will be on the cat's skin (sweated through its pores) and in its saliva. In any event, this is a relatively low-risk situation since the veterinarian facility is keeping the cat for the first two weeks when it would pose the greatest hazard. These extra precautions simply minimize any risk of exposure that might still exist. No matter what happens, your fetus' thyroid would receive very low amounts of radioactive iodine. A little care could keep the accumulation to almost nothing. Kelly Classic Certified Medical Health Physicist