Thyroid Scan

About Thyroid Scans ..

Thyroid scanning is a well established test for evaluating many thyroid diseases. The scan helps to classify the goitre into diffuse or multinodular goitres. Thyroid nodules can be classified into those that concentrate tracer (hot nodules) and those that do not (cold nodules). Distortions and extensions of the gland beneath the sternum can be seen. The thyroid scan aids in the evaluation of hyperthyroidism by demonstrating findings that differentiate Graves' disease, toxic adenoma, toxic multinodular goitre and thyroiditis.


Indications: Thyroid Scan 0001.jpg

  • Evaluation of goitre and nodules.

  • Evaluation of hyperthyroidism.


  • No thyroid hormone (Thyroxine) for 6 weeks prior to the scan, a patient can be scanned if they have been on Thyroxine for 5 days or less.

  • No Iodine based CT contrast 4 weeks prior to the scan.

  • If the patient is on Amioderone, refer to Thyroid physician.

  • Kelp, Chinese herbal remedies or iodine/potassium iodide in multivitamins need to be stopped for at least 3 weeks if 200µg or more.


  • Following an IV injection of 99mTc-Pertechnetate, there is a waiting time of approx. 20 minutes

  • The scan takes approx. 10 minutes to complete. 

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Page last reviewed: 23 March 2015