Scintigraphy (also: scintigraphy) is an imaging procedure in medicine. With the help of the injection of low-level radioactive substances and a gamma camera, certain tissue structures can be made visible.
What is scintigraphy?
Scintigraphy uses an injection of low-level radioactive material and a gamma camera to make certain tissue structures visible. Scintigraphy is used primarily to detect tumors. Scintigraphy belongs to the field of nuclear medicine, in which physicians make use of the properties of radioactive substances – for example, to examine organs or other tissue within the human body without surgery. To do this, the examiner injects a drug that is radioactively labeled: a so-called radiopharmaceutical. Since different types of tissue require different nutrients, radiopharmaceuticals also use different substances and are radioactively labeled – depending on which tissue is to be examined. A gamma camera measures the radioactive radiation emitted by the marker and can thus visualize the corresponding tissue. Two types of scintigraphy can be distinguished: Functional scintigraphy images tissue activity, while static scintigraphy primarily images structures without considering the processes occurring within them.
Function, effect, and goals
The radiopharmaceuticals used in scintigraphy accumulate in tissues to varying degrees: Tissue whose metabolism is very active is supplied by the organism with a correspondingly large number of nutrients and thus also absorbs the radioactive marker to a greater extent. This is why scintigraphy is primarily used to detect tumors; because a tumor is such 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 that area – which ultimately appears on an image (the scintigram) usually as red or yellow areas. Deformities and other abnormalities also reveal themselves on the scintigram. In addition, scintigraphy shows whether vessels are blocked or certain tissue is undersupplied. Such conditions are noticeable in the resulting image by the fact that the corresponding areas are less strongly colored than would be expected from healthy tissue. Both static and functional scintigraphy are suitable for these applications. As a rule, however, the acquisition of a static image is already sufficient. In principle, scintigraphy can be used for all organs. However, due to their location in the body and their metabolic processes, the lungs, thyroid, heart and kidneys are particularly predestined for examination with this procedure. In addition, scintigraphy is often used to examine the skeleton or individual bones. Here, bruises can already be detected – even if no injury is visible externally. Scintigraphy is mainly used in the clinical-medical field and less frequently in research with healthy subjects. This is mainly because the suspicion of a serious disease justifies the use of (potentially harmful) radioactive substances and this is also in the best interest of the patient; in the case of pure research interest, other methods tend to be used that are less invasive. Like all medical investigations, scintigraphy requires a cost-benefit consideration.
Risks and hazards
Although scintigraphy involves the use of radioactive substances, it is considered to be largely risk-free. Only pregnant women should not be examined with this method, because even low radiation concentrations can be risky for an unborn child. For the same reason, it is recommended not to be in the immediate vicinity of pregnant women after a scintigraphy until the radiation has subsided. However, this is often the case after one or two days. Caution is also advised for breastfeeding women as well as children and adolescents. For this reason, members of this group of people are only examined by scintigraphy in well-justified exceptional cases. Nevertheless, the dose of radioactive radiation in scintigraphy is no higher than in comparable procedures, such as X-rays – and is even significantly lower than in computer tomography.Prior to the examination, patients are also given the opportunity to ask questions and express concerns during an educational interview.
