Radioactive Iodine for Visitors

Radioactive iodine treatment for hyperthyroidism or thyroid cancer requires us to follow many safety rules. If a patient is planning to come to Houston Thyroid and Endocrine for a radioactive iodine treatment from outside of Houston then this page gives some general advice.

Generic Recommendations

(Please talk to your doctor about the specific details for your case)


  1. Preparation prior to treatment. Click here for more details about our radioactive iodine clinic.

    • Thyroid Cancer Patient Preparation: You will not be "ready" for radioactive iodine treatment until the patient has:

      • either withdrawn (stopped) thyroid hormone medication for at least 2-3 weeks or have been dosed with thyrogen per a protocol. It sometimes takes a couple weeks to order and set up the thyrogen medication for those injections. The choice of withdrawal from thyroid hormone replacement versus thyrogen depends on the patient's health, thyroid cancer staging, and other factors. Note that thyrogen can be quite expensive and a cash price (no insurance coverage) is approximately $3000 and takes our clinic some time to set up. You can find out more about thyrogen costs and insurance coverage through the Thyrogen One program FAQ. Here are the protocols: WITHDRAWAL PATHS: Path 1 or Path 2 or THYROGEN PATHS: Path 3 or Path 4 or Path 5.

      • waited long enough after a CT scan WITH CONTRAST. if a CT scan with contrast was done in the past, at least 2-3 months have passed since that examination. If planning a sooner treatment, them a 24 hour urine iodine collection should be done and demonstrate a level less than 100.

      • a negative pregnancy test if a female and knows not to get pregnancy for at least 6 months after iodine treatment

    • Hyperthyroid Patient Preparation: You will not be "ready" for radioactive iodine treatment until the patient has:

      • not taken methimazole or Propylthiouracil (PTU) for at least 5 days prior to the treatment date.

      • not had evidence of Graves thyroid eye disease or has been informed of the risks of iodine with eye disease or has been evaluated by a neuro-pthalomogist or has planned concurrent oral steroid dosing for known thyroid eye disease.

      • waited long enough after a CT scan WITH CONTRAST. if a CT scan with contrast was done in the past, at least 2-3 months have passed since that examination. If planning a sooner treatment, them a 24 hour urine iodine collection should be done and demonstrate a level less than 100.

      • a negative pregnancy test if a female and knows not to get pregnancy for at least 6 months after iodine treatment.

  2. Accommodations: When radioactive iodine is given, the patient must follow special precautions, including having a separate bathroom and toilet for at least the 3 days following the iodine treatment (Click here for more details on specific precautions).

    • A hotel or motel is NOT acceptable since there is a high likelihood of exposing cleaning staff and other hotel patrons to radioactive iodine. Generally, the room in which the patient sleeps have a bed with a 6-10 foot radius in which no other persons or pets are sleeping.

    • We recommend you stay in a house or condo which has a separate bathroom/toilet for the patient which makes it easier to reduce exposure to the general public.

  3. Travel: You will exposure people around you to radioactive iodine if you spend too much time or stay too close to them, Below are some general recommendations.

    • Car/Bus/ Automobile - We do not recommend traveling by car with anyone else for more than 30 -40 minutes after the radioactive iodine treatment is given. We do not recommend traveling by car/bus/auto for more than 4 hours between day 3 to day 7 after radioactive iodine is given.

    • Plane/Trains: We do not recommend plane travel for at least 5 to 7 days after radioactive iodine treatment. This will reduce the radiation load on people that are around you. Therefore we recommend you plan to remain in Houston for at least 5-7 days after the radioactive iodine treatment.

Generally, we coordinate these details with established patients at a clinic visit. We cannot coordinate the following recommendations for new patients until they have either: 1) Seen the doctor in the office to establish yourself as a patient via an in-person office visit. OR 2) Spoken to the international or concierge coordinator via the International VIP / Concierge program.