Scintigraphy belongs to the field of nuclear medicine, in which physicians benefit from the properties of radioactive substances - for example, to examine organs or other tissue within the human body without surgery.
For this, the examiner injects a drug that is radioactively labeled: a so-called radiopharmaceutical. Since different types of tissue require different nutrients, different substances are also used and radiolabeled in radiopharmaceuticals - depending on which tissue is to be examined. A gamma camera measures the radioactive radiation emanating from the marker, thereby making the corresponding tissue visible.
Two types of scintigraphy can be distinguished: functional scintigraphy reflects tissue activity, while static scintigraphy primarily maps structures without taking into account the processes involved.
The radiopharmaceuticals used in scintigraphy accumulate to different degrees in the tissue: tissue whose metabolism is very active is supplied by the organism with correspondingly many nutrients and thus also absorbs the radioactive marker.
Therefore, scintigraphy is used primarily for the detection of tumors; because a tumor is such a tissue that has an increased metabolism. Metastases, cysts or inflammations can also be detected by the same principle: The higher concentration of the marker leads to increased radioactive radiation in this area - which ultimately appears on one image (the scintigram) mostly as red or yellow areas.
Deformations and other anomalies are also revealed in the scintigram. In addition, the scintigraphy shows whether vessels are blocked or certain tissue is underserved. Such conditions are noticeable in the resulting image in that the corresponding sites are less strongly colored than would be expected from healthy tissue.
Both static and functional scintigraphy are suitable for these applications. In general, however, recording a static image is already sufficient. Basically, the scintigraphy can be used in all organs. However, due to their position in the body and their metabolic processes, the lungs, the thyroid gland, the heart and the kidneys are predestined for examination with this procedure. In addition, scintigraphy is often used to examine the skeleton or individual bones. Bruises can already be detected here - even if no injury is visible on the outside.
Scintigraphy is mainly used in the clinical-medical field and less frequently in research with healthy volunteers. This is mainly because the suspicion of a serious illness justifies the use of (potentially harmful) radioactive substances and this is also in the interest of the patient; In the case of pure research interest, other methods that are less invasive tend to be used. Like all medical examinations, scintigraphy requires a cost-benefit balance.
Although radioactive substances are used in scintigraphy, they are considered largely risk-free. Only pregnant women should not be examined with this method, since even low radiation concentrations can be risky for an unborn child.
For the same reason, the recommendation is that after a scintigraphy not in the immediate vicinity of pregnant women, as long as the radiation has not subsided. However, this is often the case after just one or two days. Caution is also required in nursing women and children and adolescents. Therefore, members of this group of people are examined by scintigraphy only in well-justified exceptional cases.
Nevertheless, the dose of radioactive radiation is not higher in scintigraphy than in comparable procedures, for example X-ray and even significantly lower than in computed tomography. Before the examination, patients also have the opportunity to ask questions and express their concerns in a discussion.