A thyroid ultrasound is used to look inside the thyroid gland in your neck and looks at whether you have any enlargement, nodules, cysts or suspicious features that may warrant further investigation. At the same time a check is made for any enlargement of the other glands (lymph nodes) in your neck.

A thyroid ultrasound scan is advisable if one or more applies to you:

• Single or multiple lumps in the neck, particularly if they have been increasing in size.
• Family history of thyroid abnormalities.
• Abnormal thyroid function indicated by blood test.
• Neck swelling especially if causing difficulty in breathing, difficulty in swallowing and hoarseness or loss of voice.

Thyroid cancers are fairly rare types of cancer and usually grow very slowly. Each year, there are approximately 1,100 new cases in the UK, accounting for 1 in 100 of all cancers. The thyroid gland is situated at the base of the throat. It absorbs iodine from the diet and produces thyroid hormones, which keep the body functioning normally.

The outlook for most types of thyroid cancer is generally very good and many people are completely cured of the disease, even if it has spread beyond the thyroid. For this reason, the thyroid ultrasound is an important examination to identify any enlargements or nodules that may be present.

No preparation is necessary for this ultrasound. You will not be required to undress although it is advisable to wear a top that allows easy access to your neck. You will be asked to lie on your back with a pillow under your head. A thin layer of a clear watery gel is applied to the front of the neck to help to increase the transmission of sound waves through the skin. A probe is placed perpendicular to the lower front part of the neck and is directed at different angles to examine both lobes of the thyroid gland.The study takes just 10 minutes to complete, after which the gel is wiped off.

While a thyroid ultrasound provides detailed information about the presence of any nodules, it cannot reliably distinguish between benign (not cancerous) and malignant (cancerous) thyroid nodules. If a nodule of significant size is detected, your doctor may refer you for fine needle aspiration (FNA), which will help determine if it is cancer, or not. For this procedure, a fine needle is inserted into the thyroid nodule under ultrasound guidance and a sample of the cells is drawn up through the needle into a syringe. The needle is removed and the sample is spread on to a slide for examination under a microscope. The skin site is cleaned and covered with a small protective plaster. The FNA feels like a small pinprick to the skin - much like a blood test and takes just a few minutes to complete. You will be able to return to your normal activities immediately afterwards.