roentgen rays

* * *

pl. n.
electromagnetic radiation of extremely short wavelength (beyond the ultraviolet), which pass through matter to varying degrees depending on its density. X-rays are produced when high-energy beams of electrons strike matter. They are physically indistinguishable from gamma rays, produced during radioactive decay. Both are used in diagnostic radiology (see radiography, nuclear medicine) and in radiotherapy. Great care is needed to avoid unnecessary exposure, because the radiation is harmful to all living things (see ionization, radiation sickness). Heavy elements, such as lead and barium, tend to stop X-rays and can be used to shield people from unwanted exposure to ionizing radiation.

* * *

electromagnetic waves of short wavelengths (approximately 0.01 to 10 nm) or corresponding quanta (wave mechanics), produced when electrons moving at high velocity impinge on various substances, especially heavy metals. They are commonly generated by passing a current of high voltage (10,000 volts or more) through a Coolidge tube. They can penetrate most substances to some extent, some more readily than others, and transform a photographic plate, which enables their use for radiography. They can also cause certain substances to fluoresce, making fluoroscopy possible. Because of the high energy of their quanta, they strongly ionize tissue through which they pass by means of the photoelectrons (both primary and secondary) that they liberate. This makes them useful in treatment of various pathological conditions (see radiotherapy). Formerly called roentgen r's.

Medical dictionary. 2011.

Look at other dictionaries:

  • Rays Ballpark — (design concept) Location 180 2nd Avenue SE St. Petersburg, Florida 33701 Construction cost $450 million (estimate) …   Wikipedia

  • Rays Engineering — Création 1973 Siège social  Osaka&# …   Wikipédia en Français

  • Rays Resort Apartments Gold Coast (Gold Coast) — Rays Resort Apartments Gold Coast country: Australia, city: Gold Coast (Southport) Rays Resort Apartments Gold Coast Located opposite to the Gold Coast Broadwater, the Rays Resort provides apartments with spectacular views across the… …   International hotels

  • Rays from the Rose Cross — is a Christian esoteric magazine established in June 1913 by Max Heindel, author of The Rosicrucian Cosmo Conception and founder of The Rosicrucian Fellowship; its original name was Echoes from Mount Ecclesia . It is issued bimonthly by The… …   Wikipedia

  • Rays Resort — (Голд Кост,Австралия) Категория отеля: 3,5 звезд Адрес: 106 108 Marine Parade, Southport, Саутпорт …   Каталог отелей

  • rays — informal, chiefly N. Amer. sunlight considered in the context of sunbathing. → ray rays a specified form of non luminous radiation: → ray …   English new terms dictionary

  • Rays de Tampa Bay — Tampa Bay Rays Fondation 1998 …   Wikipédia en Français

  • Rays Engineering — Infobox Company company name = Rays Engineering company company type = foundation = 1973 location = 7 17 5 Nagayoshi Deto Hirano ku Osaka shi, Osaka key people = Masumi Shiba (president) industry = Motorsport Automotive engineering products =… …   Wikipedia

  • Rays (Michael Nesmith album) — Infobox Album Name = Rays Type = Album Artist = Michael Nesmith Released = 2005 Recorded = Genre = Rock Length = Label = Pacific Arts Producer = Michael Nesmith Reviews = * Allmusic (no rating) [http://www.allmusic.com/cg/amg.dll?p=amg… …   Wikipedia

  • Rays of Light — Infobox music DVD Name = Rays of Light Type = Music Video Artist = Madonna Released =1999 Recorded = Format = Genre = Promo compilation Length = 25 mins Label = Warner Music Vision, Maverick, Warner Music UK Producer = Last DVD = Ray of Light… …   Wikipedia

  • Rays Hill Tunnel — Ray s Hill Tunnel is one of three original Pennsylvania Turnpike tunnels which were abandoned (this one in 1968) after two massive realignment projects. The others included the Sideling Hill Tunnel, and further west, the Laurel Hill Tunnel. The… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.