Approach Considerations

Make sure patient has not received any thyroid hormone or an antithyroid medication. This includes excess iodine ingestion and intravenous iodine contrast material^[3].

Laboratory exclusion of pregnancy and clinical exclusion of lactation are required.

Have in hand any prior studies for comparison. Also have the patient’s baseline TSH level prior to administration of radioactive iodine.

Equipment

Instruments used in radioactive iodine uptake testing include the following:^[3]

The simplest one is a probe with a single thallium activated sodium iodide crystal.
For routine diagnostic purposes, a gamma camera with a pin-hole collimator is used.
Fluorescent scanners detect nonradioactive iodine-127.
Handheld detectors are used in patients treated with¹³¹ I and that radio nucleotide is used as a local map for the surgeon as an aid to determine excision of potential thyroid tissue or metastatic thyroid cancer.

Medication

Pelletier-Galarneau M, Martineau P, Klein R, Henderson M, Zuckier LS. Reproducibility of radioactive iodine uptake (RAIU) measurements. J Appl Clin Med Phys. 2018 Jan. 19 (1):239-242. [QxMD MEDLINE Link].
Ramesh Chandra. Basic Review. Charles W Mitchell. Nuclear Medicine Physics: The Basics. 6. Philadelphia, PA: Lippincott Williams & Wilkins; 2004. 1.
Lewis E. Braverman, Robert D. Utiger. Werner & Ingbar’s The Thyroid: A Fundamental & Clinical Test. 9. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
Atkins HL. Technetium-99m pertechnetate uptake and scanning in the evaluation of thyroid function. Semin Nucl Med. 1971 Jul. 1(3):345-55. [QxMD MEDLINE Link].
Tenenbaum F, Lumbroso J, Schlumberger M, Caillou B, Fragu P, Parmentier C. Radiolabeled somatostatin analog scintigraphy in differentiated thyroid carcinoma. J Nucl Med. 1995 May. 36(5):807-10. [QxMD MEDLINE Link].
Adams S, Baum RP, Hertel A, Schumm-Draeger PM, Usadel KH, Hör G. Comparison of metabolic and receptor imaging in recurrent medullary thyroid carcinoma with histopathological findings. Eur J Nucl Med. 1998 Sep. 25(9):1277-83. [QxMD MEDLINE Link].
Meier DA, Brill DR, Becker DV, Clarke SE, Silberstein EB, Royal HD, et al. Procedure guideline for therapy of thyroid disease with (131)iodine. J Nucl Med. 2002 Jun. 43(6):856-61. [QxMD MEDLINE Link].
Read CH Jr, Tansey MJ, Menda Y. A 36-year retrospective analysis of the efficacy and safety of radioactive iodine in treating young Graves' patients. J Clin Endocrinol Metab. 2004 Sep. 89(9):4229-33. [QxMD MEDLINE Link].
Sisson JC, Freitas J, McDougall IR, Dauer LT, Hurley JR, Brierley JD, et al. Radiation safety in the treatment of patients with thyroid diseases by radioiodine 131I : practice recommendations of the American Thyroid Association. Thyroid. 2011 Apr. 21(4):335-46. [QxMD MEDLINE Link].
[Guideline] Neil Osterweil. Radioactive Iodine: Recommendations for Public, Patients. Available at http://www.medscape.com/viewarticle/740767. Accessed: May 17, 2012.
HICON. FDA. Available at http://www.accessdata.fda.gov/drugsatfda_docs/label/2011/021305s027lbl.pdf. Accessed: May 16, 2012.
Omudhome Ogbru, Jay W. Marks. sodium iodide I 131, Iodotope, Sodium Iodide I 131 Therapeutic. MedicineNet.com. Available at http://www.medicinenet.com/sodium_iodide_i_131/article.htm. Accessed: May 17, 2012.

Media Gallery

Thyroid anatomy.
Five different scintigrams taken from thyroids with different syndromes: (A) Normal thyroid; (B) Graves disease, diffuse increased uptake in both thyroid lobes; (C) Plummer disease (toxic multinodular goiter); (D) Toxic adenoma; (E) Thyroiditis (marker 99Tc).