A Thyroid scan (Tc-99m or iodine uptake) is a nuclear medicine test of the thyroid. It shows how active the thyroid or a nodule is. Typical effective dose 1 to 2 mSv, similar to about 4 to 8 months of natural background radiation (about 3 mSv a year).
General health information, not a diagnosis. In an emergency, call 102. Always consult a qualified health professional.
A Thyroid scan (Tc-99m or iodine uptake) is a nuclear medicine test of the thyroid. It shows how active the thyroid or a nodule is. Typical effective dose 1 to 2 mSv, similar to about 4 to 8 months of natural background radiation (about 3 mSv a year). What it shows: How active the thyroid or a nodule is. generated by SI from cited sources · general information, not a diagnosis · consult a health professional
How active the thyroid or a nodule is.
Overactive thyroid, hot or cold nodules.
Thyroid medicines and iodine-rich foods may need to be stopped beforehand, as advised.
Typical effective dose 1 to 2 mSv, similar to about 4 to 8 months of natural background radiation (about 3 mSv a year). Tell staff if you are or might be pregnant; the benefit usually outweighs the small risk, and shielding or alternatives can be considered.
30 minutes to 24 hours. General information, not a diagnosis. Results must be interpreted by a qualified health worker.
Nuclear medicine
Consult a doctor to interpret results — a single test does not make a diagnosis.
Uses your location once to list the nearest facilities. Nothing is stored.
What does a thyroid scan show?
How active the thyroid or a nodule is.
Why is a thyroid scan done?
Overactive thyroid, hot or cold nodules.
How do I prepare for a thyroid scan?
Thyroid medicines and iodine-rich foods may need to be stopped beforehand, as advised.
Does a thyroid scan use radiation?
Typical effective dose 1 to 2 mSv, similar to about 4 to 8 months of natural background radiation (about 3 mSv a year). Tell staff if you are or might be pregnant; the benefit usually outweighs the small risk, and shielding or alternatives can be considered.
How long does a thyroid scan take?
30 minutes to 24 hours
Why is Thyroid scan (Tc-99m or iodine uptake) done?
Overactive thyroid, hot or cold nodules.
How do I prepare for Thyroid scan (Tc-99m or iodine uptake)?
Thyroid medicines and iodine-rich foods may need to be stopped beforehand, as advised.
Is Thyroid scan (Tc-99m or iodine uptake) safe in pregnancy?
Typical effective dose 1 to 2 mSv, similar to about 4 to 8 months of natural background radiation (about 3 mSv a year). Tell staff if you are or might be pregnant; the benefit usually outweighs the small risk, and shielding or alternatives can be considered.
SI text CC BY 4.0; RadiologyInfo.org (ACR/RSNA) and MedlinePlus linked as references only, no text copied.