Radioactive Iodine I-131

Dear Linda
You need not worry as Radioactive Iodine therapy is best from of therapy for your problem.In case you are treated with this medication please refrain from coming in close contact with pregnant lady or young children (as the Radiation emitted may affect the thyroid of young babies and foetus that is undesirable) This treatment has some side effects depending on dose administered though temporary effects might be short lasting the long term effects are Hypothyroidism that is treatable.It is seen that over 5 years approximately 40 5o 50 % of treated patients may develop hypothyroidism.
The treatment is mostly without any undesirable effect.The hypothyroidism (indicated by weight gain, lethargy,feeling of dullness etc)is a problem that can be easily tackled with use of replacement therapy using same hormone Thyroxine that is inadequately produced by treated gland(that will be suggested by your physician).

I received radioactive iodine treatment after surgery for thyroid cancer. I personally was advised by my doctor to take much more severe precautions than just staying away from pregnant women and young children. The radioactive iodine will come out in your saliva, sweat, and urine. If someone else came into contact with it, it could damage their thyroid (good for you, bad for them). Personally, I even stayed away from my cat because I didn't want her thyroid to be damaged (animals have thyroids, too, after all). Here is a list I found that may be helpful:

"In addition to all the special preparations prior to an RAI scan or treatment, there are also precautions to follow afterwards. Although only a small amount of radioactivity is involved with this scan, it is still important to follow these simple precautions in order to minimize radiation exposure to your family members and friends. Since the radioactivity is excreted through all bodily fluids, mainly urine, as well as feces, sweat and saliva, it is essential to isolate these fluids. After you've had your I131 scan/treatment, you should:

1. Always wash your hands with soap and water after you use the bathroom. Dry your hands thoroughly with a towel that only you are using.
2. Separate all towels, washcloths, and bed linens. Wash all of these items separate from the family wash.
3. In order to dilute the amount of radiation in urine and feces, always flush the toilet at least two or three times after using the bathroom.
4. Wash the bathroom sink, shower, bathtub and bidet after each use.
5. Separate your plates, silverware and drinking cups. Better yet, use paper plates and plastic cutlery, so you won't have to wash your dishes separately from the rest of the family.
6. If you are cooking for the family, remember not to taste any of the food with a spoon that will be used for food preparation. Once it touches the saliva in your mouth it is considered to be contaminated and must be washed separately.
7. Sleep in a separate bed from your partner. Avoid open mouth kissing and all sexual contact.
8. Radiation exposure is directly related to the amount of time you spend with another person as well as how intimate and close your contact is with them. Avoid prolonged intimate physical contact with babies, children and pregnant women. You may perform all essential duties such as changing diapers, if no one else is available to help you. Wash your hands before and after these tasks.
9. In order to flush out the radiation faster, keep yourself well hydrated (preferably with water) so that the radioactive iodine will be passed out of your body through your urine."


As for the side-effects, nausea is probably the biggest one. If you are prone to it, ask for some pills beforehand. For me, it was rather intense for about a day.

If you do a search for "radioactive iodine precautions" you should get some other results.