X-ray machine
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Röntgenwifehand.jpg
The x-ray machine is a machine used to produce x-rays.
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History
Hermann von Helmholtz formulated mathematical equations for X-rays. Physicist Johann Hittorf observed tubes with energy rays extending from a negative electrode. William Crookes investigated the effects of energy discharges on rare gases. Heinrich Hertz began experimenting and demonstrated that cathode rays could penetrate very thin metal foil (such as aluminium). In 1887, Nikola Tesla began to investigate X-rays and produced the bremsstrahlung process. In 1895, Wilhelm Röntgen began observing and further documenting X-rays while experimenting with vacuum tubes.
X-rays are produced by bombarding a surface with high speed electrons (in vacuum). One of the first x-ray photograph was made of the hand of Röntgen's wife. The image displayed both her wedding ring and bones. On January 18, 1896 an X-ray machine was formally displayed by H.L. Smith. Upon discovery in 1895, X-Rays were advertised as the new scientific wonder and seized upon by entertainers. Circus patrons viewed their own skeletons and were given pictures of their own bony hands wearing silhouetted jewelry. While many people were fascinated by this discovery, others feared that it would allow strangers to look through walls and doors and privacy.
Early x-ray machines were used in stores to help sell shoes. These were known as fluoroscopes. However, as the harmful effects of X-ray radiation were discovered, they fell out of use. (They were more a clever marketing tool to attract customers than a fitting aid. Shoe-fitting use of the device was first banned by the state of Pennsylvania in 1957.)
How They Work
X-ray machines work by generating a beam of x-rays. The beam is projected on matter. Some of the X-ray beam will pass the object. The resulting shadow pattern of the radiation is then detected by photographic film, semiconductor plates or image intensifiers. Images taken with such devices are known as x-ray photographs or radiographs.
Uses
X-ray technology is used in health care for bones, security and material analysis.
Radiography
X-rays are highly penetrating, and x-ray machines are used in radiology to take pictures of bones and teeth. This is because bones absorb the radiation more than the less-dense soft tissue. X-rays from a source are passed through the body and a photographic plate; areas where radiation is absorbed show up as white. This can be used to diagnose broken or fractured bones. Imaging of the digestive tract is done with the help of barium, a so-called contrast medium.
Security
X-ray machines are used to screen objects non-invasively. Luggage at airports is examined for possible bombs and weapons.
See Also
External links
- Radiology Web Site Directory (http://www.xraylinks.com)
- Radiology Job Outlook (http://www.radiologyworkers.com)
- Radiology Resources for Students and Professionals (http://www.rtstudents.com)