KR101131151B1 - A tapered focus grid and the manufacturing method thereof - Google Patents

Abstract

The present invention relates to a tapered focused grid and a method of manufacturing the same, and more particularly, the upper portion of the grid is processed to be rounded to form a tapered shape so that the height of the grid is lowered toward both ends from the center. The absorber strip made of X-ray absorbing material is formed to be inclined toward the center from the center to the left and right sides of the grid, thereby effectively preventing the transmission of scattered radiation and at 1.0M to 1.8M, which is currently required in clinical practice. The present invention relates to a tapered focused grid capable of reducing the occurrence of cut off within a multi focal length and providing a stable image with homogeneity.
According to the present invention, the X-ray grid used in the X-ray image detector is formed in a tapered shape such that the upper part is rounded and the height of the grid is lowered from the center to the left and right ends thereof, and the absorption strip is formed in the grid. It provides a tapered focused grid characterized in that it is formed to be inclined toward the center toward both left and right from the center.

Description

A tapered focus grid and the manufacturing method

The present invention relates to a tapered focused grid and a method of manufacturing the same, and more particularly, the upper portion of the grid is processed to be rounded to form a tapered shape so that the height of the grid is lowered toward both ends from the center. The absorber strip made of X-ray absorbing material is formed to be inclined toward the center from the center to the left and right sides of the grid, thereby effectively preventing the transmission of scattered radiation and at 1.0M to 1.8M, which is currently required in clinical practice. The present invention relates to a tapered focused grid capable of reducing the occurrence of cut off within a multi focal length and providing a stable image with homogeneity.

With the recent development of the digital industry, medical imaging equipments are also being converted and improved digitally. As part of this aspect, recently, digital radiography (DR), which acquires digital X-ray images using existing X-ray tubes and digital radiation image detectors, has been developed to replace existing X-ray films. In order to improve the diagnostic ability, higher quality X-ray images are required.

The digital X-ray image detector detects the energy and position of the absorbed X-rays by directly or indirectly detecting the energy of X-rays absorbed at each position by the pixel-type small photo detectors arranged in a matrix form. Digitize and send to microprocessor for storage or imaging.

1 is a configuration schematically showing a digital X-ray imaging system according to the prior art.

As shown in FIG. 1, the subject 130 is positioned between the X-ray source 110 and the digital X-ray detector 140, and is a conical beam emitted from the X-ray source 110 in response to a signal from the microprocessor 150. Type X-ray 120 is irradiated to the subject 130, the X-ray 120 passing through the subject 130 is detected through the digital X-ray detector 140 and connected to the digital X-ray detector 140 A process of acquiring an image through the display of the microprocessor 150 is shown. The digital X-ray detector 140 includes a photo detector (not shown) in a matrix arrangement, and a parallel grid 142 for absorbing scattered X-rays on the front surface thereof.

As described above, in the digital X-ray detector 140 according to the related art, the scattered X-rays generated while the X-rays 120 pass through the subject are provided by installing the parallel grid 142 in front of the photo detectors arranged in a matrix form. The problem that the contrast of the X-ray image is lowered by preventing the noise from being detected by another photo detector adjacent to the photo detector at the predetermined position is reduced.

However, when the parallel grid 142 is installed in order to prevent noise caused by scattered X-rays while passing through the subject 130, the frequency of the grid line and the frequency of the pixel of the digital X-ray detector 140 generally coincide. Since the grid lines are superimposed on the pixels of the digital X-ray detector 140, the grid lines appear in the image obtained by the digital X-ray detector, or the pixels of the digital light detector provided in the form of a matrix and the frequency of the grid lines. There has been a problem in that a moire pattern is generated due to an aliasing effect on grid lines due to the frequency difference.

In order to solve this problem, a focused grid has been introduced, which has a structure in which individual strips inside the grid form a constant angle toward the X-ray source. 2 is a configuration schematically showing a digital X-ray imaging system using a focused grid according to the prior art.

As shown in FIG. 2, when the X-ray 220 emitted from the X-ray source 210, which is a point light source, reaches the digital X-ray detector 240 installed at a predetermined distance, the light beam is diffused radially. Therefore, in the case of using the focused grid 242 having a structure in which the individual strips inside the grid form a constant angle toward the X-ray source 210, since the line image of the grid is uniformly projected on all pixels, the moire pattern is formed. It does not occur.

However, even when using such a focused grid, when the focal length of the grid is 1.0M to 1.8M, which is usually required by the clinic, image quality due to scattered radiation caused by X-ray imaging is deteriorated. It still occurs, and to solve this, it is preferable to apply the ratio of the width and depth of the permeable material constituting the grid to at least 1/8 or less.

However, when the ratio of the width and depth of the transmission material is applied to 1/8 or less, it is possible to prevent the deterioration of the image quality due to the scattered radiation. (Cut off) is a serious problem that causes the image to turn white at both ends of the image.

Therefore, when using the focused grid as described above, it was difficult to apply all of them to the focal length range between 1.0M and 1.8M, which is required by a conventional clinic. There was an inconvenience in using at least two grids alternately depending on the focal length.

The present invention is to solve the above problems according to the prior art. That is, an object of the present invention is formed in a tapered shape so that the upper part of the grid is rounded as a whole and the height of the grid is lowered from the center to both left and right ends thereof, and the absorber strip made of X-ray absorbing material is formed in the grid. It is formed to be inclined toward the center from the center to the left and right ends, thereby effectively preventing scattered radiation and at the same time, the cut-off occurs within the multi focal length range of 1.0M to 1.8M, which is currently required in clinical practice. The present invention provides a tapered focused grid and a method of manufacturing the same, which can alleviate the problem and provide a stable image.

As a technical idea for achieving the above object, the present invention, the X-ray grid used in the X-ray image detector is a tapered shape so that the upper portion is rounded and the height of the grid is lowered from the center to both ends It is formed in, the absorption strip provides a tapered focused grid characterized in that the inclined toward the center toward the left and right ends at the center of the grid.

In addition, the present invention comprises the steps of mounting a planar grid consisting of the transmission strip and the absorption strip sequentially arranged in a mold having a concave round (round) shape of the upper surface, by connecting a vacuum absorber to the lower portion of the mold, the vacuum Vacuum adsorbing the planar grid mounted on the upper part of the mold through an adsorber to the upper part of the mold, cutting the upper part of the vacuum adsorbed grid flat by a milling facility, and cutting the cut grid Tapered focused grid manufacturing characterized in that it comprises a step of positioning the flat surface to the bottom by rotating the grid 180 ° after separating from, and cutting to the required size according to the specifications of the product (cutting) Provide a method.

In the case of using the tapered focused grid according to the present invention, the cut-off occurrence caused by the change in focal length from 1.0M to 1.8M, which is usually required by the clinic, is remarkably low, and is characterized by each focal length. Even without using a plurality of grids, a single grid has an advantage of obtaining a stable image evenly without degrading image quality. In addition, it is possible to effectively prevent the transmission of scattered radiation caused by X-ray imaging by maintaining the characteristics of the existing focusing grid.

1 is a configuration schematically showing a digital X-ray imaging system using a planar grid according to the prior art.
2 schematically illustrates a digital X-ray imaging system using a focused grid according to the prior art.
3 is a perspective view of a tapered focused grid according to an embodiment of the present invention.
4 is a diagram illustrating an X-ray image for each focal length using a tapered focused grid according to an embodiment of the present invention.
5 is a flowchart illustrating a method of manufacturing a tapered focused grid according to an embodiment of the present invention.
6 is a view showing a grid manufactured according to the tapered focused grid manufacturing method shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a perspective view of a tapered focused grid according to an embodiment of the present invention.

As shown in FIG. 3, the upper portion of the tapered focused grid 300 according to the present invention is formed in a tapered shape such that the height thereof is lowered toward the left and right ends from the center, so that the whole is processed round. Both ends of the grid are formed to have a thickness relatively thinner than the center portion.

Inside the grid, the transmission strip 320 made of X-ray transmissive material and the absorption strip 310 made of X-ray absorptive material are repeatedly arranged. In the present invention, the absorption strip 310 is the center of the grid 300. It is formed to be inclined toward the center toward both ends from the left and right, because the X-rays emitted from the X-ray source, which is a point light source, spread radially when they reach a flat digital X-ray detector installed at a predetermined distance. In order to prevent the X-rays from being absorbed by the absorbing strip, the effective X-rays are obtained.

As the tapered focused grid 300 formed as described above is formed in a tapered shape such that its height is lowered from the center to the left and right ends thereof, the ratio of the width and the depth of the transmission strip 320 is the left and right ends from the center of the grid. As it increases in size, it is possible to prevent a problem that the image is turned white due to a cutoff caused by the absorption strip 310 on the left and right sides of the X-ray image.

The transmission strip may use a material capable of transmitting X-rays such as plastic, polymer, ceramic, graphite, and carbon fiber, and the absorption strip may be X-ray. High absorption rate lead, gold, barium, tungsten, platinum, mercury, indium, thallium, palladium, tin tin, zinc, alloys thereof, and the like.

In addition, the tapered focused grid 300 according to the present invention may be used to prevent breakage of the grid such as separation and damage of the absorption strip 310 and the transmission strip 320 on the upper and / or lower surface of the grid. It is possible to attach a protective film in the form of a thin plate (slice) made of a light transmissive material.

4 is a diagram illustrating an X-ray image for each focal length using a tapered focused grid according to an embodiment of the present invention.

Figure 4 is to adjust the focal length of the digital X-ray imaging system to 1.0M, 1.3M and 1.8M in order to test the image quality of the image according to the focal length of the digital X-ray imaging system to which the tapered focused grid according to the present invention The test screen according to the results is shown as a), b) and c) of FIG. 4, respectively.

As shown in a), b), and c) of FIG. 4, although there is a slight difference in image quality according to the focal length, the homogeneity of the image is very stable, and it can be seen that the occurrence of cutoff is significantly lowered.

As such, in the case of using the tapered focused grid according to the present invention, the problem of scattered radiation transmittance, which is an advantage of the conventional focused grid, is solved, and at the same time without changing the X-ray focal length without using a plurality of grids. By solving the problem of cut off caused by the grid left and right absorbing strips, it is possible to prevent a problem that the images of both the left and right sides are turned white during X-ray imaging.

5 is a flowchart illustrating a method of manufacturing a tapered focused grid according to an embodiment of the present invention, and FIG. 6 is a diagram illustrating a grid manufactured according to the method of manufacturing a tapered focused grid shown in FIG. 5.

In order to manufacture a tapered focused grid according to the present invention, first, as shown in FIG. 6 (a), a mold having a concave rounded shape having a relatively large radius of curvature on the upper surface is prepared, and FIG. 6. As shown in (b) of the present invention, a transmissive strip made of an X-ray transmissive material and an absorptive strip made of an X-ray absorptive material are arranged in order to prepare a planar grid. The use of a mold having a concave rounded upper surface is to form a tapered shape such that the upper part of the grid is processed to be rounded entirely so that the height of the grid is lowered from the center to the left and right ends thereof. The round formed on the upper surface of the mold is usually formed to have a radius of curvature in the range of 40,000 mm to 80,000 mm. In this embodiment, a mold having a radius of curvature of 58,000 mm was used.

Subsequently, as shown in (c) of FIG. 6, a flat grid is mounted on the mold (S510), and a vacuum sucker is positioned below the mold to vacuum suction the flat grid mounted on the mold (S520). To this end, a plurality of through-holes are formed in the mold to be connected to the lower vacuum absorber. The lower surface of the grid is processed into a rounded convex shape downward through the vacuum adsorption process, and the absorption strip is left and right at the center of the grid. It is formed to be inclined toward the center toward both ends.

Next, as shown in (d) of FIG. 6, when the vacuum adsorption process is completed, the grid is cut flat by the milling equipment (S530). Subsequently, as shown in (e) of FIG. 6, the grid is separated from the mold, and then the grid is turned upside down so that the flat surface is positioned at the bottom (S540). The left and right cutoffs of the grid are inspected by X-rays (S550).

Subsequently, a protective film having excellent X-ray transmittance is attached to the upper and / or lower surface of the grid to prevent breakage of the grid (S560), and a cutting process is performed to cut the grid to an appropriate size in order to meet the required specifications of the product. (S570).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

110, 210: X-ray source 120, 220: X-ray
130, 230: Subject 140, 240: Digital X-ray detector
142: flat grid 150: microprocessor
242: focused grid 300: tapered focused grid
310: absorption strip 320: transmission strip

Claims (9)

In the X-ray grid used for the X-ray image detector, the transmission strip made of X-ray transmissive material and the absorption strip made of X-ray absorptive material are sequentially arranged.
The grid,
The upper part is rounded to form a tapered shape so that the height of the grid is lowered from the center to the left and right ends,
The absorption strip,
Tapered focused grid, characterized in that the inclined toward the center toward the left and right both ends from the center of the grid.
The method of claim 1,
The absorption strip,
Lead, gold, barium, tungsten, platinum, mercury, indium, thallium, palladium, tin, A tapered focused grid comprising at least one material selected from the group consisting of zinc and alloys thereof.
The method of claim 1,
The transmission strip,
A tapered focused grid comprising at least one material selected from the group consisting of plastic, polymer, ceramic, graphite, and carbon fiber.
The method of claim 1,
The grid,
Tapered focused grid, characterized in that the upper surface and / or the lower surface is formed of a thin film (slice) protective film made of an X-ray transmitting material.
In the method of manufacturing a tapered focused grid,
Mounting a planar grid composed of sequentially arranged permeable strips and absorbing strips in a mold having a concave round top surface;
Connecting a vacuum suction unit to the lower part of the mold to vacuum suction the flat grid mounted on the upper part of the mold to the upper part of the mold through the vacuum suction machine;
Cutting the upper portion of the vacuum-adsorbed grid flat by a milling facility;
Separating the cut grid from the mold, and then flipping the grid up and down to position the flat surface at the bottom;
Cutting to a required size according to the specification of the product;
Tapered focused grid manufacturing method characterized in that it comprises a.
6. The method of claim 5,
The upper surface of the mold,
Tapered focused grid manufacturing method characterized in that the concave round (round) form to have a radius of curvature of 40,000mm ~ 80,000mm.
The method of claim 6,
In the mold,
Tapered focused grid manufacturing method characterized in that at least one through hole connecting the upper surface of the mold and the vacuum absorber connected to the lower mold is formed.
6. The method of claim 5,
Before the cutting step,
Tapered focused grid manufacturing method further comprises the step of inspecting the left and right cutoff of the grid by X-rays.
6. The method of claim 5,
Before or after the cutting step,
And attaching a protective film of X-ray transmissive material to the top and / or bottom surfaces of the grid.

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