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Thyroid Ultrasound Scan

Updated: Feb 28

An ultrasound scan uses high frequency sound waves to create a picture of your thyroid gland.

A thyroid scan checks the function of the thyroid gland. It can help find out if your thyroid is working normally, or is overactive or underactive.

The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). One of its main functions is a chemical process that regulates (the body's metabolism) the rate at which the body converts food to energy.

A radioactive iodine thyroid scan uses small amounts of radioactive materials called radiotracers, a special camera, and a small computer. This provides information about your thyroid's size, shape, position and function that is often unattainable using other imaging procedures.

Please Note: This Blog is for Information Only (At Ultraworld Scanning Services we only offer Diagnostic Thyroid Ultrasound Scans)

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What is a Thyroid Scan?

A thyroid scan is a specialized imaging procedure for examining your thyroid, the gland that controls your metabolism. It’s located in the front part of your neck.

Typically, the scan works with nuclear medicine to evaluate the way your thyroid functions. Nuclear medicine involves using small amounts of radioactive material to diagnose disease.

Nuclear medicine is noninvasive and is usually painless. Thyroid scans can help your doctor determine if your thyroid is working properly. You may also have a radioactive iodine uptake (RAIU) test with the scan to measure your thyroid’s reaction.

Radioactive iodine is used in thyroid tests, including a thyroid scan. Your thyroid and most types of thyroid cancer absorb iodine naturally. The radioactive iodine builds up in your thyroid tissue. A gamma camera or scanner detects the radioactive emissions.

Radiotracers are molecules linked to, or "labeled" with, a small amount of radioactive material. They accumulate in tumors or regions of inflammation. They can also bind to specific proteins in the body. The most common radiotracer is F-18 fluorodeoxyglucose (FDG), a molecule similar to glucose.

You will usually receive the radiotracer in an injection. Or you may swallow it or inhale it as a gas, depending on the exam. It accumulates in the area under examination. A special camera detects gamma ray emissions from the radiotracer. The camera and a computer produce pictures and supply molecular information.

The thyroid scan provides information about the structure and function of the thyroid.


A thyroid scan can be used to evaluate abnormalities found in a physical exam.

The images from this test can be used to diagnose:

  • Lumps, nodules (cysts) or other growths

  • Inflammation or swelling

  • An overactive thyroid or hyperthyroidism

  • An underactive thyroid or hypothyroidism

  • Goiter, which is an abnormal enlargement of the thyroid

  • Thyroid cancer

Thyroid scan procedure

You’ll be asked to lie down on an examination table for a thyroid scan without RAIU.

Our sonographer will tip your head back so that your neck is extended. They’ll then use a scanner or camera to take photos of your thyroid, usually from at least three different angles.

You’ll be asked to stay very still while the images are taken. The process takes about 30 minutes.

Risks of a thyroid scan

There’s a small but safe amount of radiation contained in the radionuclide used in any thyroid scan. Your exposure to radiation will be minimal and within the acceptable ranges for diagnostic exams. There are no known long-term complications of having a nuclear medicine procedure.

Allergic reactions to the radionuclide material are extremely rare. The effects are mild when they occur.

Even though the radiation exposure is minimal, thyroid scans aren’t recommended for pregnant or breastfeeding women.

Your doctor can recommend that you avoid becoming pregnant or fathering a child for six months after the test if you’ve had a metastatic scan.

Thyroid scan results

A normal thyroid scan would show no abnormalities in the size, shape, and location of the thyroid gland. Your thyroid will have an even colour on the image. Spots on the image indicate abnormal growths in the thyroid.

Normal results from a metastatic scan indicate an absence of thyroid tissue and no spread of thyroid cancer.

An abnormal thyroid scan may show a thyroid that’s enlarged or out of position, indicating a possible tumor. Abnormal measurements also may show that your thyroid gland collected too much or too little of the radionuclide.

Special instructions

You may eat and drink as normal. If you are taking regular medication, continue as normal. However, if you are taking thyroid medication, some may need to be suspended before your scan.

To prevent an inaccurate result, it is best to avoid having the scan if you are taking multivitamins or anything else containing iodine, such as kelp or seaweed tablets for example, or if you have had any X-ray contrast agent injections in the last 2 months (for a CT scan for example).


We hope you found the information useful. You can download a referral form and one will be sent when you book. This will be required for an appointment at Ultraworld Scanning Services.

Please check out various other scanning packages at

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Reminder: For Information Only (At Ultraworld Scanning Services we only offer Diagnostic Thyroid Ultrasound Scans)

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