The thyroid ultrasound is a non-invasive imaging technology that permits the exploration of body organs without the use of radiation. It uses ultrasound (sounds above the threshold of human hearing). It is painless and can be done in the office. A plastic probe measuring approximately two inches in width sweeps the skin surface to look at the thyroid gland. The probe emits ultrasound waves that penetrate the skin and then return to the probe as they encounter other tissues. A computer will analyze these return sounds (echoes) and will ultimately produce a picture of the thyroid. This technology is similar to the ultrasound that the obstetrician does to look at the baby inside the mother’s womb. The doctor can use the ultrasound to guide a needle inside a thyroid nodule and increase the accuracy of the thyroid biopsy (link to thyroid biopsy). Thyroid ultrasound has revolutionized thyroid nodule diagnoses and treatments. It is also used to monitor size of nodules.
Also called FNA (fine needle aspiration), this is an office procedure where the doctor inserts a fine needle (thinner than the needle used to draw blood from the arm) through the skin of the neck into the thyroid nodule to obtain a sample of a few cells. These thyroid cells are sent to the labs where they are examined under the microscope to determine whether the nodule is benign or cancerous. The procedure is safe and complications are rarely seen. It is theoretically safer to stop aspirin five days before the procedure. If you are on treatments with other blood thinners, please discuss with the doctor how long you need to be off the medication before the procedure can be done. There will be minimal pain in the area of the FNA during the procedure and the pain will lessen over the days following the FNA. The person can resume usual activities right after the thyroid treatments. More than 60% of FNA procedures yield a benign diagnosis; about 5% will show definite thyroid cancer; about 10% will be suspicious for thyroid cancer; and 10-20% will not reveal a diagnosis and the FNA will need to be repeated on another visit. If the FNA is positive for cancer or suspicious for cancer, then total or partial thyroid surgery will be recommended.
Radioactive iodine (RAI) uptake and scan
This technology takes advantage of the property of the thyroid gland to take up iodine from the circulation and package it into thyroid hormones. It uses special molecules (isotopes) of iodine that are radioactive which means that once in the body their location in the body can be detected using a special detector. If the patient is a woman of childbearing age, a urinary pregnancy test is obtained before any radioactive material is given. RAI is given to the person as a capsule to take by mouth. The person is asked to return after 4 hours (in some cases 24 hours) to have an “uptake” done. The technologist uses a probe that is placed in front of the patient’s neck to measure how much radioactivity is retained in the thyroid area and will generate a number which will help the doctor determine the diagnosis of the thyroid condition. A thyroid scan is simply a picture of the thyroid obtained by placing a camera in front of the patient’s neck (sometimes whole body) that will trace those organs that took up the RAI (usually the thyroid gland but sometimes lymph nodes or salivary glands, etc). RAI can be safely given to those patients with allergy to iodine because the amount is less than the iodine contained in table salt. A tracer dose of RAI does not damage thyroid cells or other organs.
Radioactive iodine (RAI) treatments
This consists in giving the patient RAI by mouth in a capsule form. This takes advantage of the property of the thyroid cells to take up iodine from the circulation and concentrate it. If the dose is strong enough, it will destroy the thyroid cells. Cell death occurs after a few days. Since the thyroid gland is the main organ that concentrates iodine, it will be destroyed by the RAI. Radioactive iodine can be safely given to those patients with allergy to iodine because the amount is less than iodine present in table salt. The patient has to observe certain precautions pertaining to radioactive material like preventing inadvertent and unnecessary exposure of other persons specifically children and pregnant women. The length of time that there is risk of exposure is determined by the dose of RAI and how much radioactivity is absorbed by the thyroid gland. Radioactivity is measured in millicuries. A typical dose for the treatment of hyperthyroidism (link to hyperthyroidism) is 10-30 millicuries. Higher doses are used for the treatment of thyroid cancer and they range from 75 to 350 millicuries. After high doses of RAI, there is risk of damage to the salivary glands because they have the ability to concentrate iodine as well. This damage can be prevented by sucking on lemon drops for 24-48 hours after the RAI treatment. Depending on State regulation, the patient might need to be admitted to the hospital if they receive more than a certain dose of RAI. At Cleveland Clinic, we discharge the patient home after most RAI treatments provided that some strict criteria are met. If patients are planning to travel immediately after RAI treatment, they will need to have a letter from the treating doctor because radiation detectors used at airports can detect the radiation emitted by the patient’s body. RAI can affect fertility in both men and women and postponing pregnancy for a few months is advised in women; men should discuss with their doctor whether sperm banking is advised prior to treatment with high doses of RAI.
Other treatments: May be done at other departments, but of relevance to thyroid disease.
PET scans for thyroid cancer etc
Less invasive surgical procedures?