Common questions about nuclear medicine
Surely, your nuclear medicine physician, radiologist, or treating physician has already explained a lot about the exam to you. But, sometimes there are unanswered questions that only occur to you later, after the initial discomposure has passed. We have collected the most common questions below.
Are there contraindications for a nuclear medicine exam?
Nuclear medicine exams may not be performed during pregnancy. If you are breastfeeding, it may be necessary to interrupt breastfeeding for a brief period.
Does nuclear medicine involve high radiation loads?
Nuclear medicine exams and therapies use X-ray radiation. In contrast with radiology technologies, however, the radiation is not applied to the patient from the outside (such as with X-rays), but rather the patient is administered a radioactive substance and this can be measured. In diagnostics, the artificially produced radionuclide Technetium-99m (Tc-99m) is used most often. It has a half-life of about 6 hours, so it is very short-lived, and is generally injected intravenously. The special thing about nuclear medicine is that only very small amounts of this radionuclide are required (often in the mammary region) in order to identify metabolic processes or even individual molecules in the body. In this context we are now even talking about molecular imaging. Due to these small amounts, and the short lifespan of the radionuclides, the radiation dose is typically very low. There are really none of the typical side effects of contrast agents due to the very low doses in nuclear medicine.
Are there contrast agents or side effects of contrast agents?
No contrast agents are given for nuclear medicine. There is a very small amount of a radioactive substance (tracer), which builds up in certain organs and thus allows conclusions to be drawn about the function of an organ. Due to the very small amount of the radionuclide required, there are none of the typical side effects of contrast agents as they are rarely found in CT or even more rarely in MRT.
Why is there a thyroid consultation?
Your contact person for any questions about the thyroid gland, who also has access to any technology needed, is the nuclear medicine physician. If needed, the nuclear medicine physician can also provide or introduce therapy that will then be continued by the referring physician.
The healthy thyroid gland is a small, butterfly-shaped organ that lies beneath the throat like a shield in front of the windpipe. Normally it is not visible or palpable. The job of the thyroid gland is to produce so-called thyroid hormones from iodine and other substances (including the amino acid tyrosine), store them, and release them to the bloodstream in appropriate amounts. The release of thyroid hormones into the blood is normally strictly controlled by certain areas of the brain (pituitary gland and hypothalamus). Hyper- or hypothyroid function can have severe effects on the metabolism.
Various methods are used for exams in the thyroid outpatient center.
An ultrasound exam is used to assess and measure the appearance and size of the thyroid gland. Nodules or cysts (hollow spaces filled with fluid) can be detected, evaluated, and measured.
Thyroid scintigraphy is used to take functional images of the thyroid. This makes use of the principle that cells with higher metabolic activity (e.g., hot nodules) will take up larger amounts of a radioactive substance than cells with lower activity (e.g., cold nodules.) In these highly active regions, relatively greater amounts of radiation are released than in other regions. Cold nodules have a disproportionately higher risk of tumors, while hot nodules are often evident from their changes in metabolism.
In addition to these two imaging examination methods, the so-called thyroid levels (including FT3, FT4, and TSH) are measured in the blood, as well as important antibodies such as TPO or TRAK. This procedure can reliably detect thyroid enlargement and functional problems (hyper- and hypothyroid) and identify their causes.
Once the size and function of the thyroid gland have been checked, if necessary the nuclear medicine physician will develop a specific therapy suggestion for you, discuss it with you, and send it to your general practitioner. If necessary, a fine-needle puncture of the thyroid can be performed in the thyroid outpatient unit in order to precisely evaluate the tissue.