10 mCi of Tc-99m is the dosage required for a thyroid scan
THYROID SCANINDICATIONS:75-300 mCi I-131 p.o. for cancer treatment.
The critical organ with iodine radiopharmaceuticals is the thyroid, which receives 1-2 rad from a typical I-123 uptake and scan. Doses for I-131 are considerably higher; I-131 ablation therapy dose, over 30 mCi, require hospitalization for proper isolation. 99mTcO4 gives 0.12-0.20 rad/mCi to the thyroid.
SCANNING TIME:For 99mTcO4 scanning is begun approximately 20 minutes after injection.For metastatic workup - 48 and 96 hours post oral administration.
For thyroid uptake test -- 24 hours.
OTHER CONSIDERATIONS:Tc99m and I131 arent used in thyroid uptake and scan. Specically I123 is used to evaluate thyroid uptake and is also used to perform a scan mostly in addition to a pinhole collimator. Tc99m can be used just for the purpose of size and shape of thyroid but ultrasound is more specific for that and does not introduce a dose of radiation to the patient.
If there is a need to scan the thyroid gland, most of the time it can be done using an ultrasound scan. If further testing is needed, sometimes a doctor will order what's called a thyroid scan. A thyroid scan is a picture of the thyroid gland. This is taken after a small dose of a radioactive isotope, that is normally absorbed by the thyroid cells, has been injected or swallowed. This helps a physician determine if a growth on the thyroid is an active part of the thyroid tissue or not.
may also be referred to as a thyroid scintiscan. The name of the radioactive substance used may be incorporated and the study called a technetium thyroid scan or an iodine thyroid scan.
Because the results of the uptake will determine whether you will need surgery to remove your thyroid glands.
the ct scan said thyroid is hetergenous in apperance their is mild enlargement of the right lobe of the thyroid
Hyperdensity in a cat scan of the thyroid indicates calcifications, hemorrhage, or colloid. The thyroid gland is one of the largest endocrine glands and consists of two connected lobes.
A thyroid uptake scan wouldn't normally be needed unless it is suspected that thyroid tissue was missed during surgery (sometimes thyroid tissue can be found in other areas of the body), or the reason for the surgery was cancer and the removal of all the tissue is vital.
It depends on the type of scan but by far the most common scan uses "gamma" rays to get a picture. The radionuclide used is Tc99m which gives off gamma rays at 140 kEV, a very suitable energy level for the cameras used in nuclear medicine.
Beta blockers and other medicines are sometimes given to alleviate some of the symptoms of hypERthyroid that may occur as the result of thyroid disease or increased thyroid levels that result from the thyroid scan process. Atenolol is often used as it works more directly on heart rate with a better side effect profile.
For two days before and ten days after the injection of the radiopharmaceutical, patients are given either Lugol's solution or potassium iodine. This prevents the thyroid from taking up radioactive iodine and interfering with the scan
It's called Tc99m MDP and it's a radiopharmacuetical - a drug (MDP) with a small amount of radioactive substance (Tc99m) attached. The drug attaches itself to bone (as well as other organs like the kidneys) and the radiation is detected by special cameras. It is excreted through urine so drink lots of water to help pass it through your system, the radioactive part has a half life of 6 hours, which means there is half as much radiation there after 6 hours. After about 10 hours it's pretty much gone, overall it's a very safe test, much less radiation than a CT scan for instance.
If I-123 was not available and that is the only reason ever. Some places use Tc99m because it is cheaper and faster than I-123. But i-123 was developed because it was and is better than straight Tc99m