X-RAY ANALYSIS

From Big Medical Encyclopedia

X-RAY ANALYSIS [rentgeno-(by name V. Rentgena ) + Greek grapho to write, represent] — a method of X-ray inspection, at Krom by means of x-ray emission on material, sensitive to it, as a rule on a film, receive the fixed image of the studied object (roentgenogram).

The river is one of the main general methods X-ray inspection (see). It began to be applied at the earliest stages of development radiologies (see), soon after opening of x-ray emission. The ruble allows to receive the x-ray image of any part of a body. Owing to natural contrast of a number of fabrics it is the leading method of a research of the bone and joint device, lungs, heart, a diaphragm. The river is an obligatory component rentgenol. researches in the conditions of artificial contrasting of bodies, napr, angiography (see), urography (see). The river has a number of advantages before other main method rentgenol. researches — roentgenoscopy (see). Treat them: higher quality and detailing of the image, existence of the roentgenogram, edge can be kept for the purpose of comparison with previous and the subsequent roentgenograms (see). Beam load of the patient at R., as a rule, is less, than at roentgenoscopy.

Indications to R. match the general indications to rentgenol. to a research are also defined proceeding from a wedge, data. A relative contraindication to R. — the serious condition of the patient demanding urgent measures of medical aid.

The river is carried out by means of any X-ray diagnostic device, including mobile and figurative (see. X-ray apparatus ). The image can be received by direct impact of the x-ray emission which passed through an object on a film, to-ruyu then show and fix. As efficiency of direct impact of x-ray emission on photographic materials is small (the share of the film of energy absorbed by a photosensitive layer does not exceed 1%), for reduction of beam load of the patient resort to transformation of x-ray emission in light by means of two special luminescent X-ray intensifying screens, between to-rymi in the cartridge place a film.

Standard R. of an object is carried out, as a rule, in two mutually perpendicular projections. Sometimes additional or special projections — slanting, axial, etc. are required (see. X-ray inspection ). The pictures covering a part of a body (an abdominal cavity, a thorax, etc.) or the whole body (a stomach, a liver, etc.), call survey. Pictures of the certain small sites interesting the doctor (e.g., antral department of a stomach or a bulb of a duodenum), the roentgenoscopies which are usually carried out under control, carry the name of aim.

Allocate special types of R.: screenless, telex-ray analysis (see), contact, with direct blowup, with parallactical shift, etc.

Screenless R. (without use of X-ray intensifying screens) is applied seldom, by hl. obr. for studying of fine structure of ossicles (e.g., phalanxes of fingers), teeth, a mammary gland.

A telex-ray analysis — R. at the extended focal length (a distance between focus of a X-ray tube and the plane of a film) use for obtaining the image with the minimum projective increase.

For elimination of the details preventing identification of the studied object contact R. serves, to-ruyu carry out by approach of the studied object to the cartridge and a X-ray tube to this object.

Rubles with direct blowup make by increase in distance between a film and an object. Owing to the projective law (see. Skialogiya ) the dispersing beams give the enlarged image of an object.

Rubles with parallactical shift apply to inspection of seriously ill patients, at to-rykh difficult to receive the second projection for specification of an arrangement patol. process, definition of a depth of a foreign body, etc. Parallactical shift represents the shift of a shadow in the picture made after movement of a X-ray tube, at the same time the shadow is displaced in the direction opposite to the movement of a tube, and the it is more, than further from a film a teneobrazuyushchy object is located (see Skialogiya).

Special types of R. are fluorography (see), the cut is the cornerstone photography of the x-ray image of an object from the fluorescent screen or the screen of the electron-optical converter, and electrox-ray analysis (see), based on obtaining the temporary image on the loaded semiconductor plate, a cut then transfer to usual paper.

The river makes X-ray laboratory assistant (see), R. under control of roentgenoscopy or in the course of special rentgenol. researches (e.g., irrigoskopiya, cholecystographies) — the radiologist by means of the X-ray laboratory assistant, to-ry regulates technical specifications on R. from the operating console a X-ray apparatus. At R. measures shall be observed antiactinic protection (see) patients, especially children, and personnel. Quality roentgenograms (see) is defined by a right choice of technical specifications on shooting: in focal length, exposure (quantity of the electric power which passed through a X-ray tube during shooting), endurance (a time term, during to-rogo a film is affected by x-ray emission), wavelength (rigidity) of x-ray emission, type of X-ray intensifying screens, sensitivity of a film, etc. In a modern X-ray apparatus these conditions are set or considered automatically by the devices entering a design of the device.

The analysis of roentgenograms demands knowledge of laws of formation of the x-ray image (see. Skialogiya ), x-ray anatomy (see. Radioanatomy ) and rentgenol. symptoms of diseases (see. Radiodiagnosis ).



Bibliography: Lindenbraten L. D. and Naumov L. B. Methods of X-ray inspection of bodies and systems of the person, Tashkent, 1976; V. M Falcons. The atlas of laying during the performance of x-ray films, L., 1971, bibliogr.; it, Choice of optimal physics and technology conditions of a X-ray analysis, L., 1979, bibliogr.; M of e s with h a n I. Radiographic positioning and related anatomy, Philadelphia a. o., 1978.


V. V. Kitayev.

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