Radionuclide Uptake by the Thyroid (2)	

	Radioiodine uptake tests have been largely superseded by more-precise direct hormone assays; however, they are still used in combination with thyroid scanners to provide a map of the thyroid. Scans are particularly useful when delineating areas of active and inactive tissue in the investigation of nodular goitre, toxic nodules, ectopic thyroid tissue, and thyroid carcinoma. 131I remains the preferred isotope to use in twenty-four-hour uptake studies before 131I therapy. 

See also:
• Hormone Assay Techniques
• Imaging in Thyroid Disease