| x-rays | roentgen rays |
|---|---|
| GR | gamma-rays; gastric resection; general research; generalized rash; glucocorticoid receptor; glutathi... |
| HED | hereditary ectodermal dysplasia; hydrotropic electron-donor; hypohidrotic ectodermal dysplasia; unit... |
| rem | Roentgen Equivalent Man 1 rem = 1 rad x RBE |
| ARRS | American Roentgen Ray Society |
| RSA | Roentgen Stereophotogrammetric Analysis |
|---|---|
| EPMA | Electron Probe X rays Microanalysis |
| EDAX | Energy dispersive analysis of X-rays |
| Roentgen | <radiobiology, unit> The special unit of exposure, based on a quantity of ionisation (charge) produced by the absorption of X or gamma radiation energy in a specified mass of air under standard conditions. 1R = 2.58 x 10-4 C kg-1 or air. For radiation protection purposes, an exposure to 1 roentgen of x or gamma rays (air kerma of ~10-2 J kg-1) is generally assumed to produce an absorbed dose of 1 rad in water or soft tissue. Abbreviation: R (06 Aug 1998) |
|---|---|
| roentgen-equivalent | <radiobiology> A unit of dose equivalent to that quantity of ionizing radiation of any type that produces in man the same biologic effect as one rad of X-rays or gamma rays; the number of rems is equal to the absorbed dose, measured in rads, multiplied by the quality factor of the radiation in question.100 rem = 1 Sv. (05 Mar 2000) |
| roentgen-equivalent physical | <radiobiology, unit> A roentgen equivalent physical is a unit of absorbed radiation approximately equivalent to a roentgen, an international unit of x- or gamma-radiation. An obsolete unit of measurement; that quantity of ionizing radiation of any kind which, upon absorption by living tissue, produces an energy gain per gram of tissue equivalent to that produced by 1 roentgen of X-rays or gamma-rays. Acronym: rep See: rad. (05 Mar 2000) |
| roentgen ray | <investigation> A type of irradiation used for imaging purposes that uses energy beams of very short wavelengths (0.1 to 1000 angstroms) that can penetrate most substances except heavy metals. This is the commonest form of imaging technique used in clinical practice everywhere in the world with the image captured on photographic film. An AP film is when the beams pass from front-to-back (anteroposterior) and is used for mobile film, particularly on the ward or in casualty. This is the oposite to a PA film (posteroanterior) in which the rays pass through the body from back-to-front. Most films taken in the main radiology department are PA. (20 Jun 2000) |
| Roentgen, Wilhelm | <person, radiobiology> German scientist who discovered X-rays in 1895. (13 Nov 1997) |
| anode rays | Those originating in a gas discharge tube and moving in a direction opposite to that of cathode ray's; made up of positively charged ions. Synonym: positive rays. (05 Mar 2000) |
| Becquerel rays | An obsolete term for radiations given off by uranium and other radioactive substances; these include alpha, beta, and gamma ray's. (05 Mar 2000) |
| gamma rays | Very powerful and penetrating, high-energy electromagnetic radiation of shorter wavelength than that of X-rays. They are emitted by a decaying nucleus, usually between 0.01 and 10 mev. They are also called nuclear X-rays. (12 Dec 1998) |
| parallel rays | Ray's parallel to the axis of an optical system. (05 Mar 2000) |
| marginal rays | In geometric optics, those ray's originating from the periphery. (05 Mar 2000) |
| paraxial rays | In geometric optics, those ray's focused at the principal point. (05 Mar 2000) |
| cathode rays | A stream of electrons emitted from the negative electrode (cathode) in a Crookes tube; their bombardment of the anode or the glass wall of the tube gives rise to X-ray's. (05 Mar 2000) |
| glass rays | Those formed by cathode ray's striking the wall of an X-ray tube. (05 Mar 2000) |
| cephalometric X-rays | <dentistry> An X-ray of the head that shows whether your teeth are aligned properly, and whether they are growing properly. (08 Jan 1998) |
| monochromatic rays | Light ray's or ionizing radiation of a very narrow band of wavelengths (ideally, of a single wavelength). Compare: photopeak, characteristic radiation. (05 Mar 2000) |
| roentgen rays |
see under ray.
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