What is thyroid scintigraphy?
Thyroid scintigraphy is an examination method that makes the activity of the thyroid gland visible. Tumors, for example, can be detected in this way.
The tracer is structurally similar to iodine, which is taken up into the thyroid gland for the production of thyroid hormones. Therefore, it also accumulates in the thyroid gland. The more active the thyroid cells (thyrocytes) are, the more iodine or tracer they absorb.
MIBI scintigraphy and mIBG scintigraphy
In certain cases, the physician also uses other radioactive tracers.
In MIBI scintigraphy, the patient is administered methoxy-isobutyl-isonitrile labeled with technetium via a vein. This can be used, for example, to clarify “cold” thyroid nodules more precisely, i.e. tissue regions that produce hardly any thyroid hormones or none at all. Sometimes these nodules are malignant.
Both variants of scintigraphy (MIBI and mIBG scintigraphy) are used not only for nuclear medicine examinations of the thyroid gland, but also for those of other parts of the body.
Suppression scintigraphy
When to do thyroid scintigraphy?
Thyroid scintigraphy can be used to visualize the activity of thyroid tissue. For example, benign and malignant tumors as well as autonomies can be detected. In this context, one also speaks of cold, warm and hot nodules:
Cold node
Warm nodule
A warm nodule stores the tracer slightly more than the rest of the thyroid tissue. It may be a benign nodule (rarely malignant).
Hot nodule
The hot nodule is an area of the thyroid gland that stores the tracer intensely. This is indicative of a benign tumor that has escaped normal control by the body and is producing thyroid hormones completely independent of current demand (thyroid autonomy).
Thyroid scintigraphy can be performed while sitting or lying down. While the images are being taken, you should avoid head movements and swallowing (both can negatively affect the image quality). The examination is completely painless.
The duration of the examination depends on the tracer used: with technetium pertechnetate, the images can be taken about five to 25 minutes after the injection. With sodium iodide, you have to wait two to four hours.
Thyroid scintigraphy must not be performed during pregnancy and breastfeeding. If the examination is absolutely necessary during breastfeeding, breastfeeding should be interrupted.
The radiation exposure to which patients are exposed during thyroid scintigraphy is low.
