Definition, function and process
The Computed tomography (CT) is one of the imaging techniques of radiology. X-rays are used to make cross-sectional images or tomograms of the human body. The method is suitable i.a. for the representation of skull, brain, lung, digestive tract, all types of tissue, bones and blood vessels. The representation is purely structural, therefore, no physical functions are represented, such as the fMRI. Although the examination is completely painless, it proves to be disadvantageous the released X-ray radiation, which depending on the X-rayed body region can amount to more than five times the annual radiation exposure.
How does a computer tomograph work?
X-rays penetrate the body and are absorbed differently depending on the density of the human tissue or the bones. The more radiation is absorbed, the whiter the region appears on the CT image. Conversely, this means that particularly permeable regions, e.g. spaces filled with air, such as lungs or abdomen, appear black because they barely absorb X-rays. As a result, a black and white contrast image is created.
In contrast to conventional x-rays, computer tomography rotates an x-ray tube around the patient, allowing layered images to be taken. In the normal X-ray examination, the radiation takes place only from one source. In the final step, the computer assembles the captured images. Both two-dimensional (2-D) and 3-dimensional (3-D) images are now possible.
Procedure of a CT examination:
Lying on a mobile plate, the patient is automatically pushed into the CT scanner. CT tubes are relatively short, with a width of less than half a meter. Therefore, the examination is also suitable for patients with claustrophobia. Depending on the organ to be examined, computed tomography can be performed with and without contrast medium. Contrast agents improve the contrast of the image especially for air-rich body regions (lungs or intestines). The iodine-containing contrast agent for the intestine is usually drunk; For other organs, the doctor administers the contrast agent intravenously. The entire examination only takes between 5 and 15 minutes.
Cost of Computed Tomography (CT):
Depending on the area of the body to be x-rayed, a CT costs between € 200 and € 700.