Thyroid scintigraphy (Tc-99m)

Last revised by Yvette Mellam ◉ on 28 Feb 2023

Citation, DOI, disclosures and article data

Citation:

Radswiki T, Mellam Y, Sciacca F, et al. Thyroid scintigraphy (Tc-99m). Reference article, Radiopaedia.org (Accessed on 27 Mar 2023) https://doi.org/10.53347/rID-15560

DOI:

https://doi.org/10.53347/rID-15560

Permalink:

https://radiopaedia.org/articles/15560?iframe=true

rID:

15560

Article created:

26 Oct 2011, The Radswiki ◉

Disclosures:

At the time the article was created The Radswiki had no recorded disclosures.

View The Radswiki's current disclosures

Last revised:

28 Feb 2023, Yvette Mellam ◉

Disclosures:

At the time the article was last revised Yvette Mellam had no financial relationships to ineligible companies to disclose.

View Yvette Mellam's current disclosures

Revisions:

27 times, by 12 contributors - see full revision history and disclosures

Systems:

Head & Neck

Sections:

Imaging Technology

Tags:

nuclear medicine

Synonyms:

Tc-99m thyroid scan
Tc-99m pertechnetate thyroid scan

Tc-99m pertechnetate thyroid scintigraphy (thyroid scan) is a functional nuclear medicine study used to assess the thyroid gland. The uptake of the pertechnetate anion - similar in chemical-physical characteristics to the iodide ion (i. e. ionic size and negative charge) - in the thyroid parenchyma is mediated by the NIS (sodium-iodide symporter, a transmembrane glycoprotein). However, unlike iodine, pertechnetate anion is not incorporated into thyroid hormones.

patient preparation
- fast for 4 hours prior to exam
radiopharmaceutical
- Tc-99m pertechnetate
dose and route of administration
- 111-185 MBq (3-5 mCi) IV
time of imaging
- 20 minutes after Tc-99m pertechnetate administration
equipment
- camera: gamma camera
- collimator: pinhole
- window: 20% energy window centered at 140 KeV
procedure
- obtain anterior, LAO, and RAO views
- mark chin, suprasternal notch, palpable nodules, and surgical scars

Interpretation

Radiotracer uptake on the thyroid scan needs to be interpreted with biochemical thyroid function tests and thyroid antibodies (e.g. antithyroglobulin, antimicrosomal, thyrotropin receptor). The combination of these results can usually distinguish between the causes of thyroid dysfunction.