Radiography

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Radiography is the use of X-rays to view a non uniformly composed material such as the human body. By utilizing the physical properties of the ray an image can be developed displaying clearly, areas of different density and composition.

A heterogeneous beam of X-rays is produced by an X-ray generator and is projected toward an object. According to the density and composition of the different areas of the object a proportion of X-rays are absorbed by the object. The X-rays that pass through are then captured behind the object by a detector (film sensitive to X-rays or a digital detector) which gives a 2D representation of all the structures superimposed on each other. In tomography, the X-ray source and detector move to blur out structures not in the focal plane. Computed tomography (CT scanning) is different to plain film tomography in that computer assisted reconstruction is used to generate a 3D representation of the scanned object/patient.

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Medical and industrial radiography

Radiography is used for both medical and industrial applications (see medical radiography and industrial radiography). If the object being examined is living, whether human or animal, it is regarded as medical; all other radiography is regarded as industrial radiographic work.

History of radiography

Radiography started in 1895 with the discovery of X-rays, also referred to as Röntgen rays after Wilhelm Conrad Röntgen who first described their properties in rigorous detail. These previously unknown rays (hence the X) were found to be a type of electromagnetic radiation. It wasn't long before X-rays were used in various applications, from helping to fit shoes, to the medical uses that have persisted. X-rays were put to diagnostic use very early, before the dangers of ionizing radiation were discovered. Indeed, Marie Curie pushed for radiography to be used to treat wounded soldiers in World War I. Initially, many kinds of staff conducted radiography in hospitals, including physicists, photographers, doctors, nurses, and engineers. The medical specialty of radiology grew up over many years around the new technology. When new diagnostic tests were developed, it was natural for the radiographers to be trained in and to adopt this new technology. Radiographers now often do fluoroscopy, computed tomography, mammography, ultrasound, nuclear medicine and magnetic resonance imaging as well. Although a nonspecialist dictionary might define radiography quite narrowly as "taking X-ray images", this has long been only part of the work of "X-ray departments", radiographers, and radiologists. Initially, radiographs were known as roentgenograms.[1]

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