See. Radiologyinfo. Org.
Varies. A thyroid uptake and scan may be done with different isotopes and protocols resulting in scan time variation. Typically is done with i-123; you take the capsule one day and you come back the next day at 24 hr for a neck scan that takes aprox 15-20 minutes. In certain circumstances some places do this scan at 4-6 hours after you take the capsule. Some places do the scan with pertechnetate.
Test. Uses: hyperthyroid patients, following thyroid cancer, and as a prelude to receiving radioactive iodine to treat thyroid cancer. Should not be used routinely to work up thyroid nodules.
Just a test. A thyroid uptake and scan is used to aid the differential diagnosis of newly diagnosed thyrotoxicosis and ideally should use i-123 as the radiopharmaceutical (low energy isotope for testing). If the test shows increased thyroid function such as in grave's disease or multi-nodular goiter i-131 can be use to ablate the thyroid gland if this is desire.
None. The amount of tc99m or iodine given is a small dose and does not pose a health risk for a radioactive thyroid scan.
Always a risk. Your body/thyroid will recieve a tiny quantity of radiation exposure. Thats the risk. Have your md explain why he/she wants the test.
Thyroid scan. I assume you are referring to a nuclear thyroid scan and uptake which is usually performed for thyroid nodule and or hyperthyroidism assessment. You will be given a capsule (orally) of radioactive iodine (I-123) which has a very minimal dose of radiation, usually around 200 microcuries and you will not feel any side effects.
Thyroid scan. This scan involves taking orally a small dose of radioactive iodine. The iodine is taken up by the thyroid and produces an image. "cold" areas are places with no iodine uptake. "hot" areas have a lot of uptake. The radiologist also calculates the percent uptake of the iodine. This test is important in the diagnosis of hyperthyoidism, thyroid cancer, and follow up of thyroid cancer.
Thyroid imaging. A thyroid nuclear scan is an imaging study of the thyroid gland using radioiosotopes such as iodine 131, iodine 123, or 99mtc-pertechnetate. Following administration of one of these radioisotopes, a scan of the neck is performed to detect nodules or to evaluate the metabolic status of the thyroid, for example.
Thyroid function. The patient ingests radioactive iodine or has intravenous injection of radiotracer technetium to define structure, size, and function of thyroid gland. Overactive (hyperthyroid) normal, and underactive thyroid glands are determined. Sometimes autoimmune conditions and tumors of the gland can be suspected. Correlative imaging ultrasound, mr imaging, and blood tests are used for confirmation.
Not really. The half-life of the tc99m used in most scans is such that you are radiation free in 24hrs. Also, the amount used is very small. Don't worry.
It depends. Thyroid scans can be done with three different isotopes - most often technetium (tc-99) or iodine (i-123). Scans done to monitor patients with a known history of thyroid cancer use iodine (i-131). Tc-99 decays quite rapidly, but i-123 takes a few days to decay, and i-131 can persist at low levels for several weeks. Low doses are used, that are safe for patients and those around them.
Depends on isotope. Different isotopes have different physical half-lifes. In the us, a thyroid scan should ideally be performed using i-123 which has a half-life of 13.2 hours. Some places use a low dose of i-131which has a half-life of 8 days or tc-99m which has a half-life of 6 hours. The radioactivity used in this study is low, however the rule of thumb is 10 half-lifes for all activity to decay. Biology is also.
Usually 2 days. Half life for radiotracers used to image thyroid is 6 hours for Tc99m pertechnetate and 13 hours for Iodine 123. Usually two days after dose, no appreciable residual activity.
7days. Patient s should be on low iodine diet for one week before the the scan.
2 weeks. A low-iodine diet should usually be followed for 2 weeks prior to a thyroid whole-body scan. The rationale behind this is to reduce the chances of non-radiactive iodine (in food and table salt) to compete with the radioactive active iodine use for diagnosis (i-123) and treatment (i-131).
Regular salt is OK. Salt without iodine (if you can find it is ok). The scan requires a low iodine diet.
No iodinated salt. The thyroid uptake and scan measures the ability of your thyroid gland to accumulate a radioactive form of iodine (usually i-123). Table salt or seafood contain iodine (a non-radiactive one) that compete with the radioactive iodine use during the test and thus could falsely bias the results. You can use kosher salt which doesn't have the added iodine as in regular salt.
Check. Iodine content.
Sometimes. Most scans in the us use radioiodine. In this situation, table salt which contains iodine will interfere with the scan; sea salt generally contains very little iodine and should not interfere much with the test. If you get a tc99m pertechnetate thyroid scan, which is more commonly used in europe, sea salt before the scan is ok.
Best avoided. The thyroid scan depends upon the attraction of the gland for iodine. Sea salts are frequently rich in iodine which can interfere with the test. Best to hold off on this and iodized salt for several days prior to a thyroid nuclear scan.
Thyroid scan vs sono. The nuclear scan and the ultrasound of the thyroid are used for different reasons so one is not "better" than the other. The nuclear scan assesses the activity of the thyroid and can assess size and if the thyroid is over or underactive. The sonogram can assess the size and look for changes in density showing the presence of cysts and solid tumors.
Different no better. A thyroid nuclear uptake and scan is a functional test of your thyroid. It is useful in differentiating causes of thyrotoxicosis (excessive amounts of thyroid hormones in the body). A thyroid ultrasound is better to assess the anatomy of the thyroid gland and for guidance if biopsy is needed.