Thyroid cancer cells in your body pick up the iodine. The radiation in the iodine then kills the cancer cells. It can treat the cancer even if it has spread. But even if you have one of these types of thyroid cancer, this treatment may not be necessary or suitable for you. Not all of the cancer cells take up the iodine so you may have a test dose to see if they do.
You may only need to have this treatment once. But it can be repeated every 3 months if needed, until there is no sign of any thyroid cancer on your scans. For your treatment to work, one of the hormone levels in your body needs to be high. This hormone is called thyroid stimulating hormone or TSH.
A high level of TSH helps any thyroid cancer cells in the body to take up radioactive iodine. Your healthcare team will explain what you need to do and what is going to happen. They will also let you know when to re-start your hormone tablets if they have asked you to stop taking them. Papillary thyroid cancer cells can pick up the radioactive iodine if the possess the symporter for iodine wherever they are located in the body.
Once taken into the papillary thyroid cancer cells, the radioactive iodine delivers a local radiation treatment in the area where the iodine is concentrated. The papillary thyroid cancer diagnosis, itself, is not an indication for RAI treatment. If you had a papillary thyroid cancer, 25 years ago, you would have almost certainly been treated with surgery and RAI.
RAI treatment is primarily beneficial only when the patient has undergone a total thyroidectomy complete removal of the thyroid gland in the surgery for their papillary thyroid cancer. RAI treatment or therapy should only be used in instances where the risk of the papillary thyroid cancer coming back is greater than the potential risks of RAI therapy itself. There is no urgency to rush into treatment with RAI. RAI can be given as early as weeks following total thyroidectomy but can be delayed for months or even years following surgery.
The papillary thyroid cancer must have the symporter for iodine and take up iodine to be effective. Papillary thyroid cancers that take up iodine are called iodine avid. Importantly, the ability of a papillary thyroid cancer to take up iodine is required for RAI therapy to work but is not an indication for therapy. Papillary thyroid cancer should only undergo RAI treatment therapy in instances where the risk of the papillary thyroid cancer coming back is greater than the potential risks of RAI therapy itself.
In papillary thyroid cancer treatment, there is no urgency for the rapid delivery of RAI. Papillary thyroid cancer patients must be taken off of levothyroxine thyroid hormone T4 hormone for a minimum of four weeks, taken off of liothyrionine thyroid hormone T3 hormone for a minimum of two weeks, or receive a medication which is TSH which is a pharmaceutical production of the Thyroid Stimulating Hormone [TSH] produced as a recombinant protein which is identical to the TSH normally produced by the pituitary gland.
Additionally, papillary thyroid cancer patients must be on a low iodine diet for a minimum of four weeks to starve their body of iodine. Those patients which have undergone CAT scans with intravenous contrast must wait until their blood iodine levels have been adequately decreased usually at least two months.
Note, a desire to treat with radioactive iodine should never prevent the use of necessary CAT scans for the evaluation of a papillary thyroid cancer patient. Papillary thyroid cancer guidelines for post operative treatment with radioactive iodine were last updated in the American Thyroid Association edition. Some endocrinologists and nuclear medicine specialists order a preliminary nuclear study called a thyroid cancer uptake study. After your doctor has prepared your body for RAI by either stopping your use of thyroid hormone pills or giving injections of recombinant TSH Thyrogen , they may choose to give you a small dose of RAI and perform a special nuclear scan called a Thyroid Cancer Uptake Study.
This is a very low quantity of radioactive iodine and may be I or I In most cases, it is done the day before the higher dose RAI treatment. It is concentrated from the blood by the thyroid gland, where it begins destroying the gland's cells. A radiologist who has specialized training in nuclear medicine and others, possibly including an endocrinologist, thyroid surgeon, and radiation safety officer, will be part of your treatment team.
There is no equipment used during radioactive iodine therapy, the patient simply swallows a prepared dose. You should not eat or drink after midnight on the day of the procedure. If you have been taking anti-thyroid medications, you must stop at least three days before the therapy is given. Frequently, your doctor will recommend stopping anti-thyroid medication for five to seven days before therapy.
You will be able to return home following radioactive iodine treatment. However, you should avoid prolonged, close contact with other people for several days, particularly pregnant women and small children.
Most of the radioactive iodine that has not been absorbed leaves the body during the first two days following the treatment, primarily through the urine. Small amounts will also be excreted in saliva, sweat, tears, vaginal secretions, and feces. If your work or daily activities involve prolonged contact with small children or pregnant women, you should wait several days after your treatment to resume these activities.
Patients with infants at home should arrange for care to be provided by another person for the first several days after treatment. Your radiologist can be more specific for your given situation, but this is usually for two to five days.
Your treatment team will give you a list of other precautions to take following your treatment with I The following guidelines comply with the Nuclear Regulatory Commission:. Patients who need to travel immediately after radioactive iodine treatment are advised to carry a letter of explanation from their physician.
Radiation detection devices used at airports and federal buildings may be sensitive to the radiation levels present in patients up to three months following treatment with I Depending on the amount of radioactivity administered, your endocrinologist or radiation safety officer may recommend continued precautions for up to several weeks after treatment.
Doctors do not use radioiodine therapy in pregnant patients. Depending on the stage of pregnancy, I given to the mother may damage the baby's thyroid gland. If you are pregnant, discuss this issue with your doctor. When given to a nursing mother, radioactive iodine can reach a baby through her breast milk. Most physicians feel that this procedure should not be used in women who are breastfeeding unless they are willing to stop breastfeeding. Also, you should avoid getting pregnant for at least six to 12 months after treatment.
Hyperthyroidism treatment is almost always done on an outpatient basis because the dose required is relatively small. The radioiodine I is swallowed in a single capsule or liquid dose and is quickly absorbed into the bloodstream in the gastrointestinal GI tract.
Ask your doctor for advice on how to safely dispose of these items. This information may be used to meet the requirements of the U. Nuclear Regulatory Commission for giving written instructions to patients following treatment with radioiodine.
More specific instructions may be required in certain circumstances. How long does the radioiodine stay in your body? How can you reduce radiation exposure to others? First 8 hours: Drink one glass of water each hour and use the bathroom as soon as possible when you need to empty your bladder.
Men should sit on the toilet while urinating to decrease splashing. Use a tissue to wipe up any urine on the toilet bowl and flush twice. Wash your hands and rinse the sink.
Maintain a distance of at least 3 feet from all people. If possible, you should drive home alone.
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