RU98575U1 - X-RAY METER - Google Patents

Abstract

1. A device for radiometry, containing a system of fiducial marks made of radiopaque material, mounted on vertical posts, connected to a base made in the form of a plane-parallel plate and made in the same way as the posts from a rigid radiolucent material, characterized in that the vertical posts have a cylindrical shape and consist from two parts, upper and lower, interconnected by a thread with a fine pitch, and each rack has two fiducial marks fixed on its ends, at the points through which the geometric axis of the cylindrical rack passes, and the lower fiducial marks of neighboring racks are on the axes, parallel to the x or y axes of the device coordinate system. ! 2. The device according to claim 1, characterized in that a through transverse hole is made in the upper part of each rack.

Description

The proposed technical solution relates to the section of x-ray photogrammetry, and in particular to devices for photogrammetric calibration of x-ray devices designed for x-ray photographic survey.

A known device for x-ray containing a photomultiplier tube (PMT) with an end optical input mounted in a pipe made of a material with a high atomic number. In front of the PMT entrance window there is a fluorescent screen and a slit diaphragm with a light-protective cover made of getinax. The pipe is mounted on a goniometric device of the theodolite type. The device is designed to determine the focal length of an x-ray image (USSR Author's Certificate No. 381344 of 06/30/1971) [1].

The known device [1] is intended only for measuring the focal length of an x-ray image and does not allow to determine the coordinates of its main point. The focal length and coordinates of the main point of the x-ray image are elements of the interior orientation of the image. Without elements of interior orientation, it is not possible to solve the x-ray topographic problem by an analytical method.

Also known is a device for radiometry containing a photomultiplier, a rectangular prism above which there is a fluorescent screen and a slit cross-shaped diaphragm (USSR Author's Certificate No. 341476 of 04/22/1971) [2].

The known device [2] is intended only to determine the coordinates of the main point of the x-ray image and does not allow to find its focal length.

The closest in design to the claimed object is a device for radiometry, containing a coordinate system of radiopaque material mounted on vertical posts connected to a base made in the form of a plane-parallel plate and made, like the rack, of hard X-ray transparent material. Lead balls with a diameter of 1 mm are used as coordinate marks, and the racks and the base are made of organic glass (Cherniy A.N. Development of equipment and technology for testometric X-ray topography. The dissertation for the degree of Doctor of Technical Sciences. - M, 1988. P.207 ) [3]. This device was selected as a prototype.

The known device [3] is intended to assess the accuracy of stereoscopic x-ray photography and cannot be used to determine the elements of the internal orientation of the x-ray image.

The purpose of this proposal is to create a design that provides the ability to determine elements of the internal orientation of the x-ray image.

This goal is achieved by the fact that in the device for radiometry containing a coordinate system of radiopaque material mounted on vertical posts connected to a base made in the form of a plane-parallel plate and made, like the stands, of hard radiolucent material, the vertical posts have They are cylindrical in shape and consist of two parts, the upper and lower, interconnected by a thread with a fine pitch, and each rack has two coordinate marks fixed to it ends, at points through which the geometric axis of the cylindrical column passes, and the lower coordinate marks of adjacent columns are located on the axes parallel to the x or y axes of the device coordinate system.

Studies on patent and scientific-technical information sources have shown that the design of the proposed X-ray unit is unknown and does not follow explicitly from the studied prior art, i.e. meets the criteria of "novelty" and "inventive step".

Further, our proposal is accompanied by drawings and explanations to them. Figure 1 shows a General view of the device, figure 2 shows the design of the vertical rack, and figure 3 - geometry of shooting.

The device for x-ray diffraction has a base 1 made of a hard x-ray transparent material, such as plexiglass, in the form of a square plane-parallel plate (figure 1). Four coordinate risks 2 are applied on the sides of the base 1, designed to orient the device on the X-ray table deck. At the base 1 there are four through holes 3 (see FIG. 2) in which the lower ends 4 of the uprights 5, made of hard X-ray-transparent material, such as plexiglass, are tightly fixed. Racks 5 have a cylindrical shape and consist of two parts, the upper 6 and lower 7, interconnected by a thread 8 with a small pitch. Each rack 5 has two coordinate marks, the upper 9 and the lower 10. As the coordinate marks are used balls of small diameter, for example 2 mm, from radiopaque material, for example lead. Paired marks 9 and 10 are fixed at the ends of the uprights 5, at the points through which the geometric axis ii of the cylindrical upright passes. Moreover, the lower marks 10 of the adjacent racks are on lines parallel to the x and y axes of the coordinate system of the base 1 of the device. The threaded connection 8 is designed to align the racks 5 in height, which is carried out by rotating the upper part 6 of the rack. For these purposes, the hole 11 is intended, into which a special key is inserted.

The device for x-ray is installed on the deck of the x-ray table and oriented according to coordinate risks 2 so that the coordinate axes x and y of its base 1 are parallel to the corresponding axes of the deck of the x-ray table. The approximate value of the shooting height is set on the x-ray tripod height scale, after which the x-ray tube is moved horizontally to the x-ray position.

The device for x-ray is intended to determine the elements of the internal orientation of the image. These elements are the coordinates of the main point of the image x _o , y _o and its focal length f = Fo (the distance between the focus of the x-ray tube F and the main point of the x-ray image o (see figure 3)).

The position of the main point of the x-ray image is most easily determined graphically as the vanishing point of the projection of the straight lines AA ′, BB ′ ... For this, points a, a ′, b, b ′, m, m ′, which are the image of the coordinate marks A, A ′, are recognized on the radiograph , B, B ′, M, M ′, and straight lines are drawn through them (see FIG. 3). The intersection point of lines o is the main point of the image.

The coordinates of the main point of the image can also be calculated by the formulas obtained by solving the system of equations of lines aa ′ and bb ′:

Where

In expressions (1), (2) and (3) x _a , y _a , x _{a ′} , y _{a ′} , x _b , y _b , x _{b ′} , y _{b ′} are the coordinates of the paired coordinate labels a and a ′, b and b ′ in the image coordinate system. The focal length of the image can be determined by the formula

or

where l is the distance between the paired coordinate labels 9 and 10; c and d are the intervals for setting coordinate labels along the x and y axes of the device; x _am , y _ab and x ′ _am , y ′ _ab - the distance in the image between the images of the closest marks, respectively, of the upper and lower groups.

The proposed device can be used for stereoscopic radiography in phthisiology and other areas of medicine.

Claims (2)

1. The device for x-ray containing a coordinate system of radiopaque material mounted on vertical posts connected to a base made in the form of a plane-parallel plate and made as well as a rack of hard radiolucent material, characterized in that the vertical columns are cylindrical and consist of two parts, the upper and lower, interconnected by a thread with a fine pitch, and each rack has two coordinate marks fixed to its ends, while Kah, through which the geometric axis of the cylindrical strut, the lower fiducial marks adjacent struts are in the axes parallel to the axes x and y coordinate system devices. 2. The device according to claim 1, characterized in that in the upper part of each rack is made through a transverse hole.