Your
Therapy with
Radioactive Iodine
for Thyroid Cancer
____________________________
A Patient Education Series from
The Department of Radiology
Thank you for choosing Wake Forest University Health Sciences. Please let us know if you have questions or concerns or do not understand the information we give you. Always ask us to explain words or phrases you do not understand.
Your doctor has recommended treatment with radioactive iodine. This sheet will review what you can expect before, during and after your treatment with radioactive iodine.
What is Radioactive Iodine?
Radioactive iodine (I-131) is a substance used to destroy normal and cancerous thyroid tissue with radiation. At Wake Forest University Health Sciences (WFUHS), it is given in a capsule form and taken by mouth. It is absorbed by the gastrointestinal tract and taken up by thyroid tissue. After you take the capsule, you will be asked to follow special instructions to reduce radiation exposure to other people and to contain any excreted radioactive iodine.
How do I get ready for my therapy with radioactive iodine?
- Consultation.
We recommend a consultation with one of our nuclear medicine physicians to get to know you, review your medical records, explain the procedure, and give specific instructions for pretreatment planning of your therapy.
- Low-iodine diet.
- WFUHS recommended low-iodine diet.
- For more information and a low-iodine cookbook, please refer to www.thyca.org. You will note that recommendations on this website may differ from ours slightly.
- The recommended time to be on a low-iodine diet is usually two weeks, depending on your doctor’s advice.
- Hormonal preparation.
You can either withdraw from thyroid hormone, which requires stopping thyroid hormone for 4 to 6 weeks, or undergo a series of Thyrogen injections. The type of hormonal preparation appropriate for you will depend on your particular medical history, your personal preference, and what is recommended by your doctors.
- Assurance of non-pregnant status.
If you are a female between the ages of 11 and 55, a pregnancy test will be performed prior to your therapy unless pregnancy is not possible due to prior gynecological surgery.
What will happen during the week of my therapy?
- For patients who undergo withdrawal from thyroid hormone:
Day 1: Do not eat breakfast today. At this morning appointment, you will meet with your nuclear medicine physician. You will have lab work drawn. Once it has been confirmed that the thyroid stimulating hormone (TSH) is sufficiently elevated, a small scanning dose of radioactive iodine (I-123) will be administered by mouth. No radiation safety precautions need to be followed until after therapy on Day 2.
Day 2: You will return for a scan in the morning. You may eat a light low-iodine breakfast before 9 am. Your nuclear medicine physician will meet with you to discuss your scan and if therapy is indicated. If it is indicated, we will review the risks, benefits and indications for radioactive iodine therapy. You will be asked to sign the informed consent form. Radiation safety precautions will be reviewed with you. You will be asked to sign the Radiation safety precautions form. If you receive therapy with radioactive iodine, it is generally administered by 3 pm on Day 2. You are then discharged home to follow radiation safety precautions. The low-iodine diet and thyroid hormone withdrawal continue for 48-72 hours after therapy.
Approximately one week later: You will return for a second whole body scan. No special preparation required. Your nuclear medicine physician will review this second scan with you.
- For patients who undergo Thyrogen injections:
Day 1: This morning, you will have an intramuscular injection of Thyrogen in your upper arm or buttock. You may eat a low-iodine breakfast.
Day 2: This morning, you will have an intramuscular injection of Thyrogen in your upper arm or buttock. You may eat a low-iodine breakfast before 9 am. Do not eat lunch. Later this afternoon, you will receive a small scanning dose of radioactive iodine (I-123) by mouth. Two hours after this small dose of radioactive iodine, you may continue your low-iodine diet. No radiation safety precautions need to be followed until after therapy on Day 3.
Day 3: You will return for a scan in the morning. You may eat a light low-iodine breakfast before 9 am. Your nuclear medicine physician will meet with you to discuss your scan and if therapy is indicated. If it is indicated, we will review the risks, benefits and indications for radioactive iodine therapy. You will be asked to sign the informed consent form. Radiation safety precautions will be reviewed with you. You will be asked to sign the Radiation safety precautions form. If you receive therapy with radioactive iodine, it is generally administered by 3 pm on Day 3. You are then discharged home to follow radiation safety precautions. The low-iodine diet will continue for 48-72 hours after therapy.
Day 5: If you are not treated with radioactive iodine, you will be asked to return for labwork.
Approximately one week later: You will return for a second whole body scan if you were treated with radioactive iodine. No special preparation required. Your nuclear medicine physician will review this second scan with you.
How will I feel after therapy?
Early side effects may include nausea, occasional vomiting, pain and tenderness in the salivary glands, loss of saliva or taste, mouth ulcers, neck pain and swelling if a sizeable thyroid remnant remains after surgery, and decreased white blood cells that may result in increased susceptibility for infection. Generally,
these side effects are temporary. Late side effects are rare and can be reviewed on the informed consent form for thyroid ablation.
Why do I need to follow radiation safety precautions?
Radiation safety precautions are followed to reduce environmental contamination by bodily fluids (urine, feces, saliva, menstrual blood, tears, mucus, wounds, and ostomies) that contain radioactive iodine and to reduce radiation exposure to family members, friends, and the general public.
Your nuclear medicine physician will advise you on the number of days to follow each radiation safety precaution.
For a list of radiation safety precautions, click this link:
Radiation safety precautions.
We care about your care!
We understand that you have questions and concerns regarding therapy with radioactive iodine. Please contact the WFUHS Nuclear Medicine Department at (336) 716-3520 with any questions or concerns. We encourage you to make a consultation appointment with one of our Nuclear Medicine physicians prior to therapy for treatment planning.