Radiology is a medical specialty that uses imaging to diagnose and treat diseases seen within the body. Radiologists use a variety of imaging techniques such as X-ray radiography, ultrasound, computed tomography, nuclear medicine including positron emission tomography, and magnetic resonance imaging to diagnose and/or treat diseases. Interventional radiology is the performance of medical procedures with the guidance of imaging technologies.
The acquisition of medical imaging is usually carried out by the radiographer, often known as a radiologic technologist. Depending on location, the diagnostic radiologist, or reporting radiographer, then interprets or "reads" the images and produces a report of their findings and impression or diagnosis. This report is then transmitted to the physician who ordered the imaging, either routinely or emergently. Imaging exams are stored digitally in the picture archiving and communication system where they can be viewed by all members of the healthcare team within the same health system and compared later on with future imaging exams.
Diagnostic imaging modalities
Radiographs are produced by transmitting X-rays through a patient. The X-rays are projected through the body; an image is formed based on which rays pass through versus those that are absorbed or scattered in the patient . Röntgen discovered X-rays on November 8, 1895 and received the first Nobel Prize in Physics for their discovery in 1901.
In film-screen radiography, an X-ray tube generates a beam of X-rays, which is aimed at the patient. The X-rays that pass through the patient are filtered through a device called an grid or X-ray filter, to reduce scatter, and strike an undeveloped film, which is held tightly to a screen of light-emitting phosphors in a light-tight cassette. The film is then developed chemically and an image appears on the film. Film-screen radiography is being replaced by computed radiography but more...