When one projection is enough
Direct projection gives a general picture: the condition of the pulmonary fields, the roots of the lungs, the size and position of the heart, the condition of the diaphragm and ribs. This is enough for preventive examination, monitoring over time with an already known diagnosis and for references. The limitation is significant: behind the shadow of the heart, the dome of the diaphragm and the roots of the lungs, part of the lung tissue is hidden, and a lesion in these areas may go unnoticed on a direct image. Therefore, if pneumonia or focal formation is suspected, the doctor prescribes a study in two projections.
What does an x-ray show?
An X-ray image perfectly visualizes bone tissue and air environments: fractures and cracks, displacements, changes in joint spaces, bone growths, as well as lung tissue and its changes.
Soft tissues - ligaments, menisci, discs, cartilage - are practically invisible in the image. If the doctor suspects damage, an MRI or ultrasound is prescribed after the X-ray.
One projection or two
One projection gives a flat image, and pathology located at an unfortunate angle may go unnoticed. The second photograph, taken perpendicular to the first, eliminates this situation. In trauma, two views are the standard; shooting in one is used as screening or when the patient’s position is limited.
About radiation exposure
The dose for digital radiography is significantly lower than film and for most studies is comparable to several days of natural background radiation. However, the study is performed as prescribed by a doctor, and during pregnancy - only for health reasons with screening.