Scintigraphy is a basic examination method of the nuclear medicine. It is a whole group of examination methods that are used in diagnostics of many pathological conditions.
The basic principle is administration of a radiopharmaceutical substance, which is followed by monitoring its distribution in the body. The used substance is radioactive, but it has a very short half-life, i.e. its radioactivity quickly decreases and disappears. They are many used radioactive elements such as technetium, thallium, krypton, etc. The way of application depends on the current examination. Some substances are administered into a vein, others are inhaled. Scintigraphy operates with the fact that the particular radiopharmaceutical substance accumulates more or less in areas affected by certain pathological processes.
Note: One interesting difference of scintigraphy versus X-ray or computed tomography is that the scintigraphy is based on the radiation energy coming from the patient's body (radiopharmaceuticals) and the device absorbs the radiation. For X-ray and computed tomography, the radiation energy comes from the device.
Scintigraphy is probably most commonly used in examination of lungs, heart and bones. However, it is also possible to perform scintigraphy of other organs or whole-body scans.
This method has a great importance in the diagnosis of pulmonary embolism. The ideal method is scintigraphic examination known as combined ventilation-perfusion scan. The ventilation scan consists of inhalation of a radiopharmaceutical agent evaluation of its distribution in the lung tissue. Parts of the lungs that do not breathe do not accumulate the substance. During the perfusion scan, the radiopharmaceutical agent is injected into a vein and we check its blood flow through the lungs. Finally, we combine the results of both tests. The pulmonary embolism is characterized by occlusion of pulmonary arteries by blood clots in certain parts of the lungs with disruption of local blood flow (perfusion failure), which is in contrast with normal or only slightly reduced ventilation in these areas.
Radioactive thallium is administered intravenously and we examine its distribution in the heart muscle. The substance accumulates less in parts of myocardium affected by ischemia (lack of oxygen) and in post-infarction scars.
In this case, we evaluate the administration of a radiopharmaceutical in the bone tissue. Local changes of its concentration occur in many situations including fractures, degenerative processes, production of new bone tissue, osteomyelitis and bone metastases.
The preparation depends on the actual type of examination. Some types of scintigraphy do not require any preparation; other must be done on an empty stomach.
The only disadvantage is a certain exposure of the patient to radiation, but the dose is relatively low.
The examination is painless, patient-friendly and helps to diagnose a wide range of diseases.