Definition
Scintigraphy of the thyroid gland is a radiological (more precisely: nuclear medical) examination for the functional diagnosis of the organ. Unlike ultrasound or sectional imaging, it does not show the structure, but rather the activity and thus the hormone production. For this purpose, a substance is added to the blood, which accumulates in the thyroid gland and emits radioactive radiation. This radiation can be measured by a special camera and converted into an image by a computer.
Indications
The scintigraphy of the thyroid gland is performed, for example, if nodes are found during palpation or in the ultrasound image. In this way it can be examined whether these are hormone producing or not. All nodules larger than 1 cm should be examined. In the case of hyperthyroidism, one or more areas of increased activity may be identified as the cause by the scintigraphy. A scintigraphy is also carried out, for example, 6 months after radioiodine therapy (removal of diseased tissue by radiation from within), to check whether the treatment was successful.
Scintigraphy for Hashimoto’s thyroiditis
The scintigraphy of the thyroid gland is rather unusual in the autoimmune disease Hashimoto. For diagnosis, the determination of thyroid antibodies in the blood is particularly useful. In Hashimoto’s disease, the scintigraphy is most likely to show a reduced activity of the entire thyroid gland.
Preparation
A special preparation is usually not necessary for the scintigraphy of the thyroid gland. If you are taking medication that affects thyroid function, you should tell your doctor at the first examination, as it may affect the scintigraphy results. These include thyroid hormones (e.g.
thyroxine), iodine tablets, amiodaraone (heart medication), or drugs that inhibit thyroid function (e.g. carbimazole). If necessary, these should also be discontinued a few days before the scintigraphy. In some cases, the examination is performed specifically under the influence of thyroid hormones taken as tablets. This preparation usually takes place over a period of two to four weeks and the doctor will inform the patient accordingly in good time.
