Scintigraphy of the heart
For the heart, the so-called myocardial scintigraphy, i.e. a depiction of the blood supply to the heart muscle, is most likely to be used.It is a special method used in special cases for patients with heart disease. The examination can be a guide in answering the question of whether some areas of the heart muscle have a reduced or insufficient blood supply. Furthermore, it can be shown if the patient would benefit from an intervention that improves the blood supply.
In most cases, one recording is performed at rest and one under stress conditions. For this, the patient usually has to use a bicycle ergometer. After administration, the radioactive substance is distributed in the blood via an arm vein.
After some time it accumulates in the heart muscle tissue. In a healthy heart, the substance spreads evenly and radioactive radiation can be measured in every area. In areas with poor blood supply, the heart muscle cells absorb correspondingly fewer or no radioactive particles at all. If blood circulation is reduced only under stress but not at rest, it may be possible to improve cardiac performance by means of surgery or interventional procedures (dilation of the vessels using a cardiac catheter). A scintigraphy of the heart after an intervention can also be used to monitor the success of the procedure, i.e. it can be compared to see whether the blood flow has improved.
Scintigraphy of the lung
There are two different types of scintigraphy for the lung:
- In ventilation scintigraphy, the patient breathes in a radioactive gas (Xenon133) which is not absorbed by the body. The radiation is measured at different points in time, thus showing the distribution of the gas in the lungs. This corresponds to the ventilation.
In this way, possible flow obstacles or areas with reduced ventilation can be detected.
- In contrast, for lung perfusion scintigraphy, the radioactive particles are introduced into the blood through a vein. Due to their size and structural properties, they get caught in the smallest blood vessels of the pulmonary circulation. If areas of the lung have a weaker blood supply, they appear correspondingly weaker in the image shown by the scintigraphy.
For example, a pulmonary embolism (occlusion of a pulmonary artery by a blood clot) can be diagnosed or ruled out. In most cases, however, computer tomography with imaging of the pulmonary vessels (angio-CT) is the more common method of diagnosis. The scintigraphy is rather the second choice if the result of the CT is inconclusive.