radiography

radiography:

see X rayX ray,
invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X rays is from about 10⁻⁸ m to about 10⁻¹¹
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Radiography

a method for studying various objects, such as manufactured items and minerals, through the effect of the emissions of a radioisotope on photographic film. In radiography, external sources of ionizing radiation are used. These sources are specially produced radioisotopes placed in closed metal ampuls. In autoradiography, which is the main type of radiography, internal radiation sources are used; that is, the radioisotope is introduced into the object being studied (seeAUTORADIOGRAPHY).

If the ionizing radiation that penetrates an object registers on photographic material, the presence of areas of greater or lesser density can be discerned. This analysis derives from the uneven attenuation of radiation passing through areas free of defects as opposed to areas where defects are present. A photographic image, or shadowgraph, of the hidden defects is thus formed, which permits a determination of the shape and dimensions of these defects. In this way, radiography serves as a nondestructive technique for the quality control of cast, welded, soldered, and forged items and materials, that is, a technique for radioisotopic flaw detection.

X-ray films are most common for the purposes of radiography, whereas in autoradiography, various types of photographic materials are used. Among these materials are nuclear photographic emulsions, which permit the registering not only of the total effect, in the form of blackening, of the flux of ionizing particles on the film but also the effect of each individual particle. A chain of developed grains represents a trace, or track, of the particles on the film. The amount of radiation is measured using a characteristic curve found for each type of photographic emulsion and radiation, and the optical density of the photographic material is measured with such photometers as densitometers and microphotometers. A picture of the distribution of optical density is obtained by scanning the photographic image with the measurement aperture of a photometer. Regions of the object with a higher content of radioactive atoms correspond to regions of more intense blackening on the photographic image. This correspondence forms the basis for the radiographic study of the distribution of radioisotopes in solid objects.

The distribution of radioactive atoms in such microscopic objects as plant and animal cells and grains of metal is studied by using a microscope to examine the distribution of the particle tracks or individual developed grains of the photographic emulsion. The accuracy achieved in determining the location of isotopes in objects depends on such factors as the type and energy of the radiation, the thickness of the sample, the thickness of the film, and the distance between the sample and the photographic emulsion. Various radiographic techniques are available for different purposes. These techniques permit, for example, a detection of separate charged particles, a quantitative determination of radioactive atoms in separate regions of an object, and a measurement of the amount of ionizing radiation.

REFERENCES

Radiografiia. Moscow, 1952. (Translated from English.)
Korobkov, V. I. Metodmakroavtoradiografii. Moscow, 1967.
Bruk, B. I. A vtoradiograficheskoe issledovanie metallov, primeniaemykh v sudostroenii. Leningrad, 1966.
Rogers, A. Avtoradiografiia. Moscow, 1972. (Translated from English.)

V. I. KOROBKOV

radiography

[‚rād·ē′äg·rə·fē] (graphic arts) The technique of producing a photographic image of an opaque specimen by transmitting a beam of x-rays or γ-rays through it onto an adjacent photographic film; the image results from variations in thickness, density, and chemical composition of the specimen; used in medicine and industry.

radiography

X-rays are used to create a shadow image of light and dark, which reveals any flaws or inclusions in a test piece.The system of nondestructive testing (NDT) using X-rays or gamma rays to determine the condition of a part not visible without disassembly. Defects as discontinuities within the material show up in the density of the image of the film. X-ray inspection is used to examine the inside of the structure for corrosion or damage that deforms the structure. For detection of defects in small parts, gamma rays (cobalt-60; iridium-192) may be used.

radiography

the production of radiographs of opaque objects for use in medicine, surgery, industry, etc.

radiography

[ra″de-og´rah-fe] the making of film records (radiographs) of internal structures of the body by exposure of film specially sensitized to x-rays or gamma rays. adj., adj radiograph´ic.body section radiography tomography.double-contrast radiography mucosal relief radiography.electron radiography radiography consisting of electronic images that can be computer enhanced, electronically reversed, stored, retrieved, transmitted, and/or printed on photographic film.mass radiography examination by x-rays of the general population or of large groups of the population.mucosal relief radiography a technique for revealing any abnormality of the intestinal mucosa, involving injection and evacuation of a barium enema, followed by inflation of the intestine with air under light pressure. The light coating of barium on the inflated intestine in the radiograph reveals clearly even small abnormalities; double-contrast r.neutron radiography that in which a narrow beam of neutrons from a nuclear reactor is passed through tissues; especially useful in visualizing bony tissue.panoramic radiography pantomography.serial radiography the making of several exposures of a particular area at arbitrary intervals.spot-film radiography the making of localized instantaneous radiographic exposures; see also film" >spot film.

ra·di·og·ra·phy

(rā'dē-og'ră-fē), Examination of any part of the body for diagnostic purposes by means of x-rays with the record of the findings usually exposed onto photographic film. Synonym(s): roentgenography

radiography

(rā′dē-ŏg′rə-fē)n. The process by which radiographs are made. Also called skiagraphy.

radiography

Roentgenography, radiographic imaging Imaging The recording of an image of a region placed in a beam of radiation. See Angiography, Cholangiography, CT imaging, Fluoroscopy, GI series, IVP, Mammography, MRI, Venography, Xeroradiography.

ra·di·og·ra·phy

(rā'dē-og'ră-fē) Examination of any part of the body for diagnostic purposes by means of x-rays with the record of the findings usually impressed on a photographic film.

radiography

The use of X-radiation to produce images that can help in diagnosis. Radiography includes the use of CT SCANNING, which is an X-ray technique,RADIONUCLIDE SCANNING and, by courtesy, magnetic resonance imaging (MRI). Compare RADIOLOGY.

Radiography

Examination of any part of the body through the use of x rays. The process produces an image of shadows and contrasts on film.Mentioned in: X Rays of the Orbit

ra·di·og·ra·phy

(rā'dē-og'ră-fē) Examination of any body part for diagnostic purposes with x-rays with the record of the findings exposed onto photographic film.

radiography

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radiography:

Radiography

REFERENCES

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Synonyms for radiography

noun the process of making a radiograph

Synonyms

Related Words

noun photography that uses other kinds of radiation than visible light

Related Words