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Thyroid Uptake Study


  • You have been referred for a Thyroid Uptake Study to look at how well your thyroid gland is functioning.

  • A Thyroid Uptake Study study can assess:

    • Functionality of thyroid nodules (these are usually found on Ultrasound or may be felt).

    • Goitre including hyperthyroid goitre (enlarged overactive thyroid gland).

    • Uptake function before radio-iodine treatment.

    • Ectopic thyroid tissue.

    • Suspected thyroiditis (underactive thyroid gland).

    • Hypothyroidism (underactive thyroid gland).

    • Neonatal hypothyroidism.

  • Upon arrival to the department, a small amount of sterile liquid “tracer” is injected into a vein in your arm.

  • The tracer we use is called 99mTc-Pertechnetate (99m-Technetium Pertechnetate).

  • 99mTc-Pertechnetate is trapped (but not organified) by the thyroid follicular cells.

  • There are rarely any side effects with the injection.

  • Imaging of the Thyroid gland is commenced 20 minutes after the injection.

  • You are required to lie still on a bed whilst a Gamma Camera (1) takes images of your neck.

  • ​Imaging can take anything from 15 to 30 minutes.

  • You receive a slight radiation dose by having a Thyroid Study ~ up to 1.0 times your yearly background radiation (2).


Patient Preparation:

  • If you are pregnant, trying to fall pregnant or breast feeding, you must inform our staff.

  • If you are taking Neo-Mercazole (Carbimazole) or Propylthiouracil (PTU), you can continue taking these prior to your 99mTc Thyroid Uptake Study.

  • Thyroxine (Levothyroxine Sodium) and Tri-iodothyronine (T3) should be stopped for three weeks prior to imaging.

  • A low Iodine diet is ideal for 2 weeks prior your test i.e. Avoid: Seaweed and Kelp products, Agar, Carrageen, Sushi, Seafood, Multivitamins, Skin products with Iodine, Iodized Salt, Milk/Dairy products, Eggs, FDC Red dye #3, Chocolate, Commercial Bread with Iodine, cough syrups, etc...

  • Investigations with Iodine contrast media should be avoided for at least 8 weeks prior imaging.

  • Amiodarone can effect the thyroid uptake for up to 2 years after cessation. Please seek advise from your doctor or call us to discuss.

  • If you have had prior imaging e.g. PET, Nuclear Scan, CT, MRI, X-Ray, Ultrasound, etc... please bring these with you.

  • Please also bring your referral and any blood results that you may have had done.

  • Bring a list of any medications you are taking.

  • Wear comfortable clothing and minimise the amount of metal jewellery you have on (all metal objects around your neck and chest will need to be removed prior to imaging).


  • Important Note: You cannot have this test if you have had a PET or Nuclear Scan within 24 hours prior to this test. If you have had Iodine-131 therapy, allow 4-weeks before having this test. Please ring to discuss booking options.​


Breast-Feeding Mothers: Once you have been given the tracer, you need to stop breast-feeding for 24-hours. During this time, you need to express and discard your breast milk as often as required. You will need to bottle-feed your child during this period.


(1) A Gamma Camera is a device that detects gamma-rays (gamma-rays are very similar to x-rays) and does not emit any radiation..

(2) We all receive a yearly background radiation dose ~ 2.4mSv. Tc-99m Thyroid Uptake Study ~ 2.4mSv = 1.0 times yearly background dose.

value. quality care. convenience.

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