RU43087U1 - DEVICE FOR VISUALIZATION OF THE X-RAY IMAGE - Google Patents

Abstract

The utility model relates to x-ray technology, namely to x-ray devices and can be used in medical x-ray devices to obtain digital x-ray images. A device for visualizing an X-ray image is made in the form of a pyramidal tube, in the larger base of which there is a scintillation screen installed in the front focal plane of the optical lens, in the rear focal plane of which there is a photodiode array, the output of which is connected to the image processing device. What is new is that a heat shield is installed in the device, which is installed between the optical lens and the photodiode array.

Description

The utility model relates to x-ray technology, namely to x-ray devices and can be used in medical x-ray devices to obtain digital x-ray images.

To serve bedridden patients, as well as patients in private clinics or small hospitals that need accurate x-ray diagnostics, a new generation of x-ray machines (RA) has appeared, capable of obtaining high-quality film images directly in the ward by the patient's bed. Recently, however, digital images have been widely used, which have a number of advantages over conventional images.

Firstly, they can be examined in detail, highlighting individual fragments of the image on a computer display and changing their scale, for example, to study the structure of the bone (in the diagnosis of osteoporosis, etc.) or to determine the structure of tissues in mammography.

Secondly, digital pictures can be easily stored in electronic archives and, if necessary, quickly search for a picture.

Thirdly, digital images are easily transmitted over the Internet to specialized centers for consultation.

Fourth, devices for directly converting spatially modulated X-ray radiation into a digital image can eliminate the procedure for processing exposed film and generally eliminate the need for a darkroom.

To convert conventional X-ray images to digital images, there are special devices - digitizers, which allow you to convert them to digital format. However, it makes sense to purchase such devices if the number of images is several hundred per day. For those medical institutions where the number of images is only a few pieces per day, it is not economically feasible to purchase a device. In this case, it is economically feasible to equip the X-ray machine with an autonomous image converter obtained on a scintillation screen into a digital image.

A device for visualizing an X-ray image is known (see US patent No. 4598369, MKI G 06 F 15/42, 1986), including a scintillation screen onto which the x-ray radiation transmitted through the object is incident, reflecting a mirror directing the light image obtained on the scintillation a screen to the input of a television camera, the output of which is connected to an image processing device that allows, after further computer processing, to save the resulting images in digital form.

The main disadvantage of the known device is the low quality of digital images obtained, associated with the resolution of a television camera. Good modern digital video cameras have a resolution of about 2,000,000 pixels, which allows them to get a very high-quality digital video image, but when shooting frame-by-frame, it’s enough only to obtain an image of 1400 × 1400 pixels. Thus, on a screen of 400 × 400 mm (16 × 16 inches), we will have a resolution of only about 90 pixels / inch or about 3.5 pixels / mm, while conventional film x-rays with amplifying screens have a resolution of at least 6 pairs of lines / mm or 12 pixels / mm. Those. the resulting digital image is almost 4 times lower resolution than the film image.

Closest to the claimed technical solution (prototype) is a device for obtaining digital x-ray images (see US patent No. 4598369, MKI G 06 F 15/42, 1986), in which the radiation transmitted through the object is sent to a special device made in in the form of a pyramidal tube, in the larger base of which there is a scintillation screen mounted in the front focal plane of the optical lens, in the rear focal plane of which there is a cooled photodiode array, the output of which is connected n with the image processing device. To protect the photo diode array from spurious X-ray illumination, a protective filter made of lead glass is installed between the scintillation screen on the lens. Thanks to the cooled photodiode array, it is possible to provide a significant dynamic range of output signals, because when the matrix crystal is cooled, dark currents and thermal noise are significantly reduced.

The main disadvantage of the known device is the complexity of its compact implementation. This is due to the fact that the compact design of the device requires the use of a short-focus lens capable of converting a light image of a scintillation screen (400 × 400 mm) into an image equal to the size of the matrix (24 × 24) mm. At the same time, the proximity of the lens to a deeply cooled matrix (temperature

of the matrix should not be higher than minus 60 ° С) leads to heterogeneity of the temperature field inside it, therefore, to a change in geometric characteristics due to inhomogeneous thermal expansion and a decrease in image quality on the matrix surface.

The problem solved by this useful model is the creation of a compact device capable of converting an x-ray image of an object into its digital image.

The specified task in the device for visualization of the x-ray image, made in the form of a pyramidal tube, in the larger base of which there is a scintillation screen installed in the front focal plane of the optical lens, in the rear focal plane of which there is a photodiode array, the output of which, connected to the image processing device, is achieved the fact that a heat shield is additionally inserted into the device, installed between the optical lens and the photodiode array.

The introduction of a heat-shielding screen between the optical lens and the photodiode array allows their thermal isolation to be carried out, and thereby compactly implement the device using a short-focus lens, and thereby improve the quality of the resulting digital image.

As a heat shield, we can use glass, the surface of which is equipped with a heating element in the form of a conductive film. By adjusting the temperature of the heat shield, it is possible to achieve complete thermal isolation between the lens and the photodiode array.

The heat shield is made in the form of a glass plate, on one of the surfaces of which a discrete heating element is glued. With a small glass thickness (0.5-1.0 mm), a discrete heating element is glued to the edge of the base of the plate. With a glass thickness of 2 mm or more, a discrete heating element can be glued to the side surface of the plate. This embodiment of the heat shield is the easiest to manufacture and provides almost 100% transmission of light to the photodiode array.

The heat shield is made in the form of a glass plate, on one of the base surfaces of which a resistive film is applied. The specified implementation of the heat shield allows for high uniformity of heating of the glass plate with a transmittance of light on the photodiode array up to 98%.

A lead glass plate can be used as a glass plate of a heat shield. Such glass can serve as an additional

a screen that protects the photo-diode array from spurious x-ray illumination. In this case, there is no need to install an additional filter to eliminate spurious X-ray radiation transmitted through the scintillation screen.

Figure 1 presents a figure explaining the use of the inventive device in the composition of the x-ray apparatus.

Figure 2 presents a figure explaining the design of a heat shield with a discrete heating element.

Figure 3 presents a figure explaining the construction of a heat shield with a sprayed resistive heating element.

The figure shown in Fig. 1 includes: an x-ray emitter 1, an irradiated object 2, a scintillation screen 3 placed in a light-tight tube 4, an optical lens 5, a heat shield 6 and a photo-diode array 7.

Presented in figure 2, the design of the heat shield using a discrete heating element includes: glass 8 and a heating element 9 glued to one of its surfaces.

The design of a heat shield with a deposited resistive heating element shown in FIG. 3 includes: glass 8, a resistive heating layer 10, and electrical input contacts 11.

The device operates as follows.

An X-ray emitter 1 irradiates the object 2 and the x-ray radiation transmitted through it makes the scintillation screen 3. The lens 5 projects an optical image from the screen 3 onto a deeply cooled photodiode array 7. To exclude the influence of the cooled matrix 7 on the lens 5, a heat shield 6 is installed. Suppose that as the screen used coated with a resistive film 10 glass 8 (figure 3). To heat the glass 8, a constant or alternating regulated voltage is applied to contacts 11. The electric current passing through the resistive coating 10 heats the glass 7 and thereby prevents exposure to the cooled matrix 7. The current strength is selected experimentally depending on the thermal power released by the coating 10, the cooling temperature of the matrix, and also external temperature conditions.

As the receiving photodiode array, the Fillfactory matrix, model IBIS 4-14000, with a size of 24 × 30 mm and a volume of 14000000 pixels, which allows you to get an image of about 3000 × 3000 pixels or about 7 pixels / mm, was used.

Design options for the heat shield are given in the following examples.

Example 1

A heat-resistant (tempered) lead glass 2 mm thick was used as a heat shield, on which a transparent resistive film of tin oxide was applied by resistive evaporation. The technology for applying the film is similar to the resistive film used in the manufacture of heated glasses for the production of double-glazed windows. As electrodes, copper sprayed electrodes with a thickness of 0.1 mm were used. With a 30 × 30 mm heat shield, about 1 W of supplied electric power is enough to eliminate the influence of the cooled matrix on the lens.

Example 2

A heat-resistant (tempered) lead glass with a thickness of 2 mm and a size of 30 × 30 mm was used on which a discrete resistive heater with a power of 1 W and a size of 2 × 5 × 30 mm was glued from one edge (see Fig. 3).

Thus, the claimed technical solution eliminates the influence of the cooled matrix on the lens, which ensures high quality of the obtained x-ray images.

Claims (4)

1. A device for visualizing an X-ray image, made in the form of a pyramidal tube, in the larger base of which there is a scintillation screen installed in the front focal plane of the optical lens, in the rear focal plane of which there is a photodiode array, the output of which is connected to the image processing device, characterized in that the device additionally introduced a heat shield installed between the optical lens and the photodiode array. 2. The device according to claim 1, characterized in that the heat shield is made in the form of a glass plate, on one of the surfaces of which a discrete heating element is glued. 3. The device according to claim 1, characterized in that the heat shield is made in the form of a glass plate, on one of the base surfaces of which a resistive film is applied. 4. The device according to claim 1, characterized in that a lead glass plate is used as the glass plate of the heat shield.