RU2276578C1 - Radiodiagnosing screen - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: radiodiagnosing screen has case made of hard X-ray transparent material. Lamellas of definite mutual orientation are fixed inside the case. Two groups of lamellas are made in form of top and bottom flat parallel walls of chamber filled with inert gas under pressure. Lamellas of top wall have to be at the same plane with corresponding lamellas of bottom wall. Edges of lamellas are mounted for contact with inert gas inside chamber. Lamellas of any group are electrically connected together and are connected to electric circuit, which has high voltage source, reservoir capacitor, amplifier and microprocessor.

EFFECT: optimal exposition at radiography.

2 cl, 4 dwg

Description

The present invention relates to medical equipment and is intended to improve the quality of x-ray images with minimal radiation exposure to the patient. Rasters refer to X-ray filtering devices that are introduced into a direct beam to selectively absorb scattered radiation.

Known x-ray raster, which is a plate composed of alternating transparent and low transparency for radiation lamellas. Low-transparent lamellas are made of metal with a high atomic number and are arranged in parallel. The raster plate is fixed in a holder connected to a mechanical drive. The movement mechanism of the raster is made in the form of an electric drive with a cam. It is intended to eliminate the image of the raster lamellas on an X-ray image [1, p.325].

The disadvantage of the analogue [1] is the presence in its design of a mechanical drive, which increases the cost of the product and limits its use in a number of special studies.

A known X-ray diagnostic raster containing lamellas made of metal with a high atomic number, for example lead, is fixed at a certain relative orientation in a hard X-ray transparent material, for example carbon fiber. The lamella planes are directed to a certain point in space, with which, when using a raster, the focus of the emitter is combined [2, p.41]. Modern technology makes it possible to produce lead lamellas quite thin, which makes them practically invisible in the x-ray image. Therefore, thin-structure rasters [2] are rigidly fixed on an X-ray tripod in front of an X-ray cassette or digital X-ray image receiver.

The analogue [2] was chosen by us as a prototype.

The disadvantage of the prototype is that in its design there is no exposure meter that provides optimal radiography. This drawback can lead to loss of image quality and to excessive exposure of the patient.

The aim of the invention is to ensure optimal exposure during radiography.

This goal is achieved by the fact that in an X-ray diagnostic raster containing a housing made of hard X-ray opaque material, in which lamellas are fixed at a certain mutual orientation, two groups of lamellas are made in the form of upper and lower plane-parallel walls of the chamber filled with inert gas under pressure, while the lamellas of the upper wall are in the same plane with the corresponding lamellas of the bottom wall, and the ends of the lamellas are installed with the possibility of contact with the inert gas of the chamber, the lamellas of each group are electrically are closed to each other and respectively connected to an electric circuit including a high voltage source, a storage capacitor, an amplifier and a microprocessor, the groups are electrically closed to each other and connected to opposite poles of an electric power source connected to an amplifier and a microprocessor.

The invention is further illustrated by drawings and a description thereof.

Figure 1 shows the x-ray diagnostic raster (side view in section); figure 2 is a top view. Figure 3 shows the electrical circuit of the x-ray raster, and figure 4 shows the position of the raster in the composition of the x-ray device.

The X-ray diagnostic raster has a rectangular housing 1 made of a rigid X-ray transparent dielectric material, such as plexiglass. Inside the housing 1 is a chamber 2 filled with an inert gas 3, for example argon, under pressure. The upper 4 and lower 5 walls of the chamber 2 are plane-parallel plates consisting of alternating transparent and low-transparent lamellas for radiation. The opaque lamellas 6 and 7, respectively, of the upper 4 and lower 5 walls of the chamber 2, are made of metal with a high atomic number, for example, lead. The ends of the lamellas 6 and 7 are in contact with the inert gas 3 of the chamber 2. The planes of the lamellas 6 and 7 have a central projection orientation and are directed to the focus F of the x-ray tube 8. The lamellae 7 are geometrically conjugated with the corresponding lamellas 6, i.e. are in the same plane. All lamellas 6 are connected by electric wire 9 to terminal 10 of connector 11. All lamellas 7 are connected by electric wire 12 to terminal 13 of connector 11. The housing 1 of the X-ray diagnostic raster is mounted in a case 14 made of an X-ray transparent dielectric, such as plexiglass.

The chamber 2, filled with an inert gas 3 under pressure, with which the metal lamellas 6 and 7 are in contact, is an ionization chamber. Through terminals 10 and 13, it is connected to an electrical circuit that contains a high voltage source V, a storage capacitor C (the voltage change across the capacitor is a measure of the amount of electricity accumulated as a result of gas ionization in the chamber), an amplifier 15, and a microprocessor 16 (Fig. 3) .

An x-ray diagnostic raster is located under the deck 17 of the x-ray table above the x-ray receiver 18, for example, an x-ray cassette (figure 4). Patient 19 is located on deck 17, above which an X-ray emitter 20 is located with an X-ray tube 8. An X-ray emitter 20 is connected to the X-ray supply device 21. The X-ray diagnostic raster is also connected to the X-ray supply device 21 through the electronic unit 21. The electrical circuit of the electronic unit 22 is shown in FIG. .3.

During exposure, direct X-rays (a in FIG. 4) pass between the lead rails 6 and 7 of the raster towards the radiation receiver 18. The scattered radiation (b in FIG. 4) is delayed by the lead rails 6. Under the action of direct x-rays, ionization of the gas 3 of the chamber 2 occurs and an electric current arises in the electric circuit of the ionization chamber, increasing the charge of the storage capacitor C (Fig. 3). At a certain level of this charge, the microprocessor 16, included in the electronic unit 22, gives a signal to turn off the high voltage.

The implementation of the x-ray raster in the form of an ionization chamber of the passage type reduces the radiation load on the patient and improves the quality of the x-ray image.

Sources of information (analogues)

[1] Chikirdin EG, Mishkinis A.B. Technical encyclopedia of the radiologist. - M.: "MNPI", 1996.

[2] Fundamentals of X-ray diagnostic technology. - Edited by N.N. Blinov, M .: Medicine, 2002.

Claims (2)

1. X-ray diagnostic raster containing a housing made of hard X-ray-transparent material, in which lamellas are fixed at a certain mutual orientation, characterized in that the two groups of lamellas are made in the form of upper and lower plane-parallel walls of the chamber filled with inert gas under pressure, while the lamellas of the upper wall are in the same plane with the corresponding lamellas of the bottom wall, and the ends of the lamellas are installed with the possibility of contact with the inert gas of the chamber, the lamellas of each group are electrically closed between other and respectively connected to the electric circuit comprising a high voltage source, a storage capacitor, an amplifier, and a microprocessor. 2. The X-ray diagnostic raster according to claim 1, characterized in that the inert gas filling the chamber is argon.

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