X-ray examinations | CLINICAL CENTRE

In the past, radiology examinations used to refer - almost exclusively - to X-raying. Nowadays this is referred to as conventional X-ray imaging as several new diagnostic imaging techniques have also been developed recently. X-ray imaging is based on the fact that X-rays penetrate the human body (and any other living or non-living matter) with a portion of the rays being absorbed. The unabsorbed or “remaining” rays can be collected on a sheet of special film or detector material, where chemical or other reactions produce a shadow (or create an electronic image). The contrast, i.e. what structures can be differentiated, depends primarily on the examined part itself, on its thickness and material (density or chemical structure). It is also influenced by the intensity (energy) of the applied X-ray beam, which can be adjusted by the assistant controlling the device. This produces a summation (superimposed) image, which refers to the fact that the film shows all the organs and tissues rays go through. This unfortunately may cause problems for example in case of chest images which show the lung containing mainly air and thus being “transparent”, and superimposed on it there is the heart and other soft structures in the mediastinum (the space between the two lungs in the chest containing the esophagus, the trachea, the large vessels entering and leaving the heart, lymph nodes, etc.) as well as the ribs. This distracting effect can be attenuated by making images from several different directions. Another option would be to make multilayer images; their use, however, is rather restricted due to the availability of CT and MRI scanning. Despite all hardships and the availability of modern equipment, traditional X-ray imaging still has a say both in present diagnostics and in the foreseeable future. Its use has, however, decreased due to a significant change. While in the past several diseases were only detectable on the basis of the resulting abnormalities (or a space-occupying lesion) or a visible calcification, that is based on indirect signs, today the majority of these diseases is directly detectable and the size of the abnormalities can also be accurately measured.  For example, in case of brain tumors conventional X-ray imaging is not used any more, CT or MRI scans are performed instead.  All the same, there are still a number of disorders that are primarily or as first line examined using X-ray imaging.  An example for that is limb bone injury, where it is mostly enough to make images from two directions. X-ray imaging is also informative in certain spine conditions. Furthermore, it serves as primary and first imaging technique in thoracic (mostly pulmonary) disorders.