Endocrinology• Updated 21 October 2026
Thyroid Scan
A nuclear medicine scan that shows how active the thyroid gland and nodules are.
Results: Same day or next day
Quick Summary
Primary Purpose
To find the cause of an overactive thyroid and check nodules.
What It Measures
Uptake of tracer by the thyroid.
Preparation
Stop some thyroid medicines and avoid iodine-rich foods as advised.
Overview
Graves' disease shows high, even uptake; hot nodules make too much hormone.
Not done in pregnancy or breastfeeding.
What It Measures
Uptake
How much tracer the thyroid takes up.
Pattern
Even or patchy.
How It's Performed
- 01
Tracer
Swallowed or injected.
- 02
Scan
A camera takes pictures of the neck.
- 03
Afterwards
Follow advice about contact with children.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Thyroid Tests(opens in a new tab) · MedlinePlus, US National Library of Medicine