SU979853A2 - Device for producing raster x-ray stereo picture - Google Patents

Description

(5) DEVICE FOR OBTAINING RASTEN X-RAY STEREHOW

one

The invention relates to stereo photogrammetry, more specifically to devices for obtaining raster stereo images.

According to the main author. St. N 708152 discloses a device for obtaining a raster x-ray stereo image containing an x-ray tube mounted on a carriage mounted on a guide parallel to the plane of the cassette, on the surface of which a ruled raster is fixed. The Retnen beam is limited by two identical slit diaphragms whose width is equal to the width of the raster elements. The slit diaphragms are oriented parallel to the elements of the raster and form a vertical and inclined radiation plane. Elements of the line raster are installed in one row on the surface of the cassette and are made in -. de figures having a rectangular triangle shape in cross section, one

From the legs of which the perpenn-i of the diculary of the cassette passes, and the hypotenuse forms with it an angle equal to the angle between the planes of radiation C13.

A disadvantage of the known device is that it does not protect the subject from that part of the x-rays, which are delayed by the raster material and do not participate in the formation of the image. Since this portion of the rays account for 50% of the total beam of rays, the patient receives excessive double radiation.

The purpose of the invention is to reduce the radiation load on the subject.

Claims (1)

The goal is achieved in that the device containing the X-ray tube has slit diaphragms, the X-ray tube being fixed on the carriage which is mounted on a guide parallel to the plane of the cassette on the surface of which the ruled raster is fixed. 39, an additional ruled, raster, identical to the main one, installed parallel to the latter between the slit diaphragms of the radiation source and the subject is introduced so that identical elements of both rasters are located on the same axis perpendicular to the plane of the cassette, and the distance between the raster planes is 2n t, where E is the height of the line raster element, anlu, combat is a positive integer. FIG. 1 shows schematically the structure of the device; in fig. 2 shows the geometry of the relative position of the lower and upper ruled rasters. The X-ray tube 1 is installed in the X-ray shroud 2 and secured by a vertical 3 and horizontal k carriage, respectively, on a guide 5f parallel to the plane of the X-ray film 6 located in the cartridge 7. The x-rays are limited by two identical slit diaphragms 8 and 9, which form a steep 10 and oblique 11 slit X-ray beams. The device uses two identical ruled rasters. The lower raster 12 adjoins the x-ray cassette 7. and the upper one (13 is fixed above the shooting object Ti parallel to the lower raster 12 by means of support posts 15. The elements 16 of the lined rasters 12 and 13 are made in the form of figures having the shape of a rectangular triangle, one of the legs of which runs perpendicular to the plane of cassette 7, and the hypotenuse forms an angle with it equal to the angle between the radiation planes. The interval between the elements 16 of each raster at the entrance is equal to the width of the leg k parallel to the plane of the cassette 7 and at the output of the interval l between elements 16 is equal to 2k. Moreover, elements 1b of the lower 12 and its 13 rastror are located strictly one above the other at a distance of 2πE, where is the height of the elements of the ruled raster, an is any positive integer. This dependence is easily obtained from the construction (Fig. 2), where the upper raster 13 is removed from the lower (12) at a distance of 8. The efficiency of the coxpa-i system is also non-existent when the upper raster 13 is removed from the lower (12). The values are 2, 46, б, 10Е, 12 Е , or in general terms, with L 2h 6.. Consequently, without changing the design of the rasters, they can be used for stereo filming of objects of different thickness, setting them at the optimal distance calculated by the formula L 2n. Before shooting, the object 1A of the study is placed on the deck of the sample table 17I and the X-ray tube 1 is shifted to one of the extreme positions. Stereo-X-ray diffraction is performed by moving the x-ray tube 1 once along guide 5. At the same time, those rays that are not involved in the formation of the x-ray stereo image are delayed by the elements of the upper raster and do not adversely affect the subject. A raster stereo pair is formed on a single X-ray film and is a combination of alternating information lines defined by sheer and oblique slit X-rays. The raster image can be observed using any of the known methods, for example, using a lens mask. The depth of the structural elements of the object under study can be determined by measuring a raster image and then calculating using the formula h pctgoC, where parallax is the defined point; and ot is the angle between the radiation planes. The device will be used primarily in X-ray diagnostics, since its design allows one to reduce the radiation load on the patient by half. The invention The device for - obtaining a raster x-ray stereo image by author. St. No. 708152, characterized in that, in order to reduce the D1 radiation load on the subject, an additional line raster, identical to the main one, is installed parallel to the latter between the slit diaphragms of the radiation source and the subject so that identical elements of both rasters are located on the same axis. 5379853 perpendicular to the plane of the cassette, and the distance between the planes of the rasters is 2n | where is the height of the element, and n is any integer positiveN708152, cl. G 01 C 11/06, 1978 number. Information sources taken into account during the examination 1. USSR author's certificate (prototype).