RU98889U1 - X-ray fluorography camera - Google Patents

Abstract

 An X-ray fluorography camera comprising a light-proof casing protected by lead with an entrance window covered by a plate of X-ray transparent and opaque material, to which a flat-screen screen consisting of a substrate, a binder layer and a phosphor adjoins; inside the body there is a fast lens and a photorecorder, characterized in that an additional Fresnel ring lens is optically coupled to it, optically conjugated with the lens, while the optical input of the Fresnel lens is adjacent to the phosphor.

Description

The alleged technical solution relates to the field of medical technology, more specifically to x-ray fluorographs used for screening the diagnosis of diseases of the organs of the chest cavity.

Known X-ray fluorography camera KF-70T, developed by the Zagorsk Optical-Mechanical Plant. (Chikirdin EG X-ray fluorographic apparatus. - M: Medicine, 1970. - P.7) [1].

X-ray fluorography camera KF-70T contains a light-tight case, protected by lead, with an entrance window closed by a plate of X-ray transparent and light-tight material, which is adjacent to a flat-shaped screen, consisting of a substrate, a bonding layer and a phosphor; Inside the body there is a fast lens and a photo recorder. The photorecorder contains a tape drive mechanism and an automatic control circuit connected to it with a photo exposure meter. Fluorography is performed on a roll film of a width of 70 mm.

The main disadvantage of film cameras [1] is the unacceptably large radiation load on the patient. Currently, film fluorographs are discontinued.

Known x-ray fluorography camera, in which the photodetector uses a storage screen deposited on the surface of the drum. After exposure, the reading of the latent image is carried out using an infrared laser (Copyright certificate No. 1018623, dated 13.10.82, АВВ 6/00) [2].

The use of a photo detector with a storage screen [2] allows one to reduce the radiation load on the patient by an order of magnitude. However, this X-ray technology is extremely expensive.

In our country, photo detectors with a memory screen are not available and are not used in the practice of phthisiopulmonology.

An X-ray fluorography camera is also known, comprising a light-proof casing protected by lead, with an entrance window closed by a plate of X-ray transparent and light-tight material, to which a flat-shaped fluorescent screen is adjacent. Inside the case is a photo recorder. The optical connection between the fluorescent screen and the photorecorder is carried out using a fiber optic focon, the optical input of which is closely adjacent to the surface of the phosphor of the fluorescent screen (Copyright certificate for the invention No. 633173 from 04/28/07, IPC А61В 6/00) [3].

For X-ray fluorographic examination of an adult's lungs, the diameter of the optical input of the focon in the analogue [3] should be at least 57 cm. The optical industry could not master the production of such focons. In addition, such foci have a huge mass, which complicates their practical use. For these reasons, the invention [3] has not found clinical application.

An X-ray fluorography camera is also known, comprising a light-proof casing protected by lead, with an entrance window closed by a plate of X-ray transparent and opaque material, to which a flat-screen screen consisting of a substrate, a binder layer and a phosphor is adjacent. Inside the body there is a fast lens and a photorecorder with a CCD matrix, which is connected to a readout and signal processing board (X-ray diagnostic devices edited by N.N. Blinov and B.I. Leonov. - M .: VNIIMT, 2001, p.198) [four]. Fluorographic cameras of the type [4] are called digital. It is the closest constructively to the claimed object, and therefore was chosen by us as a prototype.

When photographing from a fluorescent screen, only 1% of the light flux enters the camera lens and is involved in image formation. This is due to the wide radiation pattern of the phosphor under the action of x-ray radiation (VV Dmokhovsky, EG Chikirdin Physicotechnical fundamentals of fluorography / Fundamentals of fluorography. - Leningrad: Medicine, 1965. - P.11). This circumstance is a great drawback of all types of fluoroscopes, in the design of which fluorescent screens are used, since it forces to increase the exposure time, which leads to excessive exposure of the patient.

The aim of our proposal is to reduce the radiation dose to the patient. This goal is achieved by focusing the light flux from the fluorescent screen using an annular Fresnel lens. For this, in a fluorographic camera containing a light-tight housing protected by lead, with an entrance window closed by a plate of X-ray transparent and opaque material, which is adjacent to a flat-shaped screen, consisting of a substrate, a bonding layer and a phosphor, inside which a fast lens and a photo recorder are installed, additionally An Fresnel ring lens is introduced, which is optically conjugated to the lens, while the optical input of the Fresnel lens is adjacent to the phosphor.

Studies on patent and scientific and technical information sources have shown that the design of the proposed X-ray fluorography camera 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 a drawing and an explanation to it (figure 1).

The X-ray fluorography camera contains a light-tight housing 1, protected by lead, with an entrance window 2, a closed plate 3 made of X-ray transparent and light-tight material, for example carbon fiber, adjacent to the fluorescent screen 4. The screen has a flat shape and consists of a substrate 5, a bonding layer 6 and a phosphor 7 having an epitaxial structure. Such a phosphor is a system of needle crystals of CsI-Na, acting as optical fibers. A phosphor with a zpppxial structure combines a high energy output of luminescence with a higher resolution.

Inside the housing, a fast aperture 8 and a photo recorder with a CCD array 9 are installed, which is connected to the read and signal processing board 10.

The optical input of the Fresnel ring lens 11 adjacent to the surface of the phosphor 7 is comprised of a central part 12 and side rings 13. The Fresnel ring lens 11 is optically coupled to the lens 8. Most of the radiation of CsI-Na needle crystals propagates normally to the output plane of the phosphor 7. These rays they are refracted by a Fresnel ring lens and sent to the lens 8, where they are assembled at the axial point S of the plane of the field diaphragm of the lens 8, which is at a distance f from the output plane of the phosphor.

This design of the optical part of the X-ray fluorography camera allows you to direct most of the luminous flux of the fluorescent screen 7 into the lens 8 of the photographic recorder, resulting in reduced exposure time and radiation load on the patient, at least twice.

The light quanta, passing through the lens 8, fall into the CCD matrix 9, where they are converted into an electrical signal, which is fed to the read-out and signal processing board 10 and then to the fluorograph computer (not shown in Fig.).

The proposed design of the X-ray fluorography camera can be widely used in pulmonology and phthisiology, especially when examining children, as it provides a significant reduction in radiation exposure to the patient.

Claims (1)

An X-ray fluorography camera comprising a light-proof casing protected by lead with an entrance window covered by a plate of X-ray transparent and opaque material, to which a flat-screen screen consisting of a substrate, a binder layer and a phosphor adjoins; inside the body there is a fast lens and a photorecorder, characterized in that an additional Fresnel ring lens is optically coupled to it, optically conjugated with the lens, while the optical input of the Fresnel lens is adjacent to the phosphor.