JPH05224356A - Light shielding device for x-ray sensitive member - Google Patents

Abstract

PURPOSE:To provide a light shielding device capable of picking up a clear precise X-ray image on an X-ray sensitive member and to prevent the occurrence of pinholes in a black light shielding film by improving the black light shielding film. CONSTITUTION:This light shielding device for an X-ray sensitive member 11 shields an accumulative phosphor as the X-ray sensitive member 11 from external light by covering with a black light shielding film 15. This light shielding film 15 is a film of carbon as a simple substance formed by carbonizing a polymer formed into a thin film shape or a carbon-contg. polyimide resin film formed by bonding fine carbon powder with polyimide resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding device for shielding an X-ray photosensitive member such as a photosensitive film, a photosensitive dry plate or a stimulable phosphor from being exposed to sunlight or indoor lighting.

[0002]

2. Description of the Related Art The above X-ray photosensitive member is widely used in X-ray photography and other fields. As is well known, a photosensitive film is a polymer material coated with a photosensitive emulsion.
The photosensitive dry plate is, for example, a glass plate coated with a photosensitive emulsion and dried. The stimulable phosphor is sometimes called a stimulable phosphor, and is a substance having the following properties. That is, when the stimulable phosphor is irradiated with radiation such as X-rays, energy is accumulated as a latent image in the stimulable phosphor corresponding to the irradiated portion, and the stimulable phosphor is further illuminated by a laser beam or the like. When the exhaustion excitation light is irradiated, the latent image energy becomes light and is emitted to the outside. Examples of such substances include BaFX:
There are known phosphors represented by Eu (X is a halogen) or various phosphors listed as visible or infrared stimulable phosphors in JP-A-56-11392.

The following method is known as one of the X-ray imaging methods using the above various X-ray photosensitive members. That is, the X-ray photosensitive member is covered with a cover having a black light-shielding film, and the X-ray photosensitive member is stored in a light-shielded state. Then, during X-ray photography, the X-ray photosensitive member is irradiated with X-rays through the black light-shielding film with the cover still attached,
An X-ray image is formed on the X-ray photosensitive member. The X-ray photosensitive member having an X-ray image is then carried into a dark box or other light-shielding atmosphere, where the cover is removed and the X-ray image reading process is performed in that state.

Conventionally, a so-called black paper, which is produced by mixing pulp fibers and carbon powder and making them with a paper machine, has been used as a black light-shielding film for shielding the X-ray sensitive member from light.

[0005]

However, in the above black paper, when it is attempted to contain a large amount of carbon in order to obtain a sufficient light-shielding property, the pulp fiber is large and the thickness thereof becomes as thick as several hundreds of microns. However, there is a problem that the amount of X-ray absorption increases. If the X-ray absorption amount of black paper is large, a large amount of X-rays will be generated when the X-ray photosensitive member is exposed to X-rays through black paper.
The lines are absorbed by the black paper and do not contribute to the exposure of the photosensitive member, so that a clear X-ray image cannot be obtained.

Since the black paper is thick, the X-ray diffraction peak cannot be ignored. Therefore, when the X-ray photosensitive member is exposed to X-rays through the black paper, the black paper itself is exposed to the diffraction rays. The member is exposed to light, and the accurate X-ray image that is originally desired cannot be obtained. Further, the above black paper is apt to cause pinholes, and therefore, an exposure test had to be performed before actually using it.

The present invention has been made in order to solve the above-mentioned problems in the conventional light-shielding device using black paper. By improving the black light-shielding film, it becomes clear on the X-ray photosensitive member. It is an object of the present invention to provide a light-shielding device capable of capturing an accurate X-ray image. Another object is to prevent pinholes from being generated in the black light shielding film.

[0008]

In order to achieve the above-mentioned object, a first light shielding device for an X-ray photosensitive member according to the present invention comprises an X-ray shielding member.
A light shielding device for an X-ray photosensitive member, which is configured to shield an X-ray photosensitive member from external light by covering it with a black light shielding film,
It is characterized in that the black light-shielding film is constituted by a carbon simple substance film which is a thin film material formed by forming a polymer material into a thin film and subjecting the film to carbonization treatment. This carbon simple substance film is a thin film formed only of carbon and does not include a fiber structure such as pulp fiber.

In the second light-shielding device for an X-ray photosensitive member according to the present invention, the black light-shielding film is composed of a carbon-containing polyimide resin film formed by bonding carbon fine powders with a polyimide resin. It is characterized by This polyimide resin is a resin obtained by polycondensation of an aromatic tetrabasic acid and an aromatic diamine.

[0010]

Both the carbon simple substance film and the carbon-containing polyimide resin film described above have excellent light-shielding properties because they contain carbon, and when they are used as a light-shielding film for an X-ray photosensitive member, the photosensitive member is Be sure to block light. When capturing an X-ray image on the X-ray photosensitive member, the photosensitive member is irradiated with X-rays through the black light-shielding film with the black light-shielding film still attached.
Both of the carbon simple substance film and the carbon-containing polyimide resin film have a small X-ray absorption amount and a good light-shielding efficiency, and therefore a large X-ray diffraction peak does not appear. Therefore, the X-ray photosensitive member is irradiated with a pure X-ray image having high intensity and containing no diffracted X-ray component which becomes noise. Therefore, a clear and accurate X-ray image is formed on the X-ray photosensitive member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the overall structure of a light-shielding device for an X-ray photosensitive member according to the present invention and its usage will be described. FIG. 2 is a view for reading an energy latent image stored in a light-shielding device 2 for an X-ray photosensitive member and a stimulable phosphor (which will be described later in detail) as an X-ray photosensitive member stored in the light-shielding device 2. The reading unit R is shown. The reading unit R includes a rectangular dark box 1 and various devices stored in the dark box 1. Examples of the devices stored therein include a table 3 for mounting the light shielding device 2, a cover attaching / detaching device 4, and a reading device 5. The table 3 is driven by the table drive device 6 and is capable of reciprocating linear translation along the guide rod 7 in the direction of arrow AA ′.

A rectangular opening 8 is formed on the upper surface of the dark box 1, and a dark box cover 10 is provided along one side of the opening 8. This dark box cover 10 is installed on the upper surface of the dark box 1 by means of hinges 9, 9 and has an opening 8
Can be opened and closed as shown by an arrow B between a position for covering the opening and a position for opening the opening 8.

As shown in FIG. 3, the light-shielding device 2 includes a rectangular parallelepiped phosphor base 12 and a rectangular thin storage phosphor 11 bonded to the front surface of the phosphor base 12. , And a light-shielding cover 13 having a size capable of covering the outer peripheral side surface of the phosphor base 12. An opening 14 having substantially the same area as the area of the stimulable phosphor 11 is formed in the light-shielding cover 13, and a black light-shielding film 15 is adhered to the periphery of the opening 14 so as to close the opening 14.

Mounting pressure tips 16 are fixedly disposed on the four peripheral side edges of the light-shielding cover 13 (two of them 13a and 13b are shown in the figure). Further, on the four peripheral side edges (two of them 12a and 12b are shown in the drawing) of the phosphor base 12, concave portions having a triangular cross section are provided at positions corresponding to the respective pressing tips 16. 17 are provided. Each pressing tip 16
As shown in FIG. 4, each of them has a cylindrical housing 18 with a narrowed lower end, a rigid ball 19 provided at the inner tip of the housing 18, and a compression spring 20 for urging the ball 19. It is composed of and.

Around the stimulable phosphor 11, an elastic member such as sponge rubber 21 is provided along the entire outer peripheral edge of the phosphor base 12. A projection 22 having a triangular cross section is provided in an annular shape on the back surface of the light shielding cover 13 corresponding to the sponge rubber 21.

The reading unit R having the above structure will be described below.
And the handling of the shading device 2 will be described. The light shielding device 2 is stored in a state in which the phosphor base 12 to which the stimulable phosphor 11 is adhered is covered with the light shielding cover 13 to which the black light shielding film 15 is adhered. Shading cover 13
When covering the phosphor base 12, the light-shielding cover 13 is attached to the outside of the phosphor base 12 from the direction in which the stimulable phosphor 11 is bonded, as shown by the arrow C in FIG. At the time of this mounting, the ball 19 in the pressing tip 16 (FIG. 4)
First, the side surfaces 12a, 12b of the phosphor base 12 are
For example, it is pushed into the housing 18 against the spring force of the spring 20 (FIG. 4). When the light shielding cover 13 is pushed to a predetermined mounting position for the phosphor base 12,
The pressing tip 16 moves to a position corresponding to the side surface recess 17 of the phosphor base 12. When the pressing tip 16 moves to that position, the side surface 12 of the phosphor base 12 is until then.
The ball 19 pushed into the housing 18 by a, 12b, etc. moves into the recess 17 by the spring force of the spring 20 and fits into the recess 17. As a result, the light shielding cover 13 is firmly connected to the phosphor base 12.

At this time, the projection 22 provided on the light-shielding cover 13
1, as shown in FIG. 1, enters into the sponge rubber 21 provided on the periphery of the phosphor base 12, and the sponge rubber 21
Elastically deform. The elastically deformed sponge rubber 21 completely fills the space between the light-shielding cover 13 and the phosphor base 12 over the entire area, whereby the phosphor base 1 is
The stimulable phosphor 11 adhered to 2 is completely shielded from external light.

When X-ray imaging is performed on the stimulable phosphor 11 in the light shielding device 2, a sample (not shown) to be imaged is irradiated with X-rays, and the X-rays diffracted or scattered by the sample. The stimulable phosphor 11 is irradiated through the black light shielding film 15. As a result, an X-ray latent image is formed in the stimulable phosphor 11.

Storage phosphor 1 having an X-ray latent image
The shading device 2 containing 1 is inserted into the dark box 1 through the dark box opening 8 as shown by an arrow D in FIG.
It is mounted on the table 3 in the dark box 1. Then, the dark box cover 10 is closed as shown by arrow B. A sponge rubber 21 is attached around the dark box opening 8, and an annular protrusion 22 having a triangular cross section is provided on the dark box cover 10 at a portion corresponding to the sponge rubber 21.
Are formed. When the dark box cover 10 is closed as described above, the cover protrusion 22 pushes the sponge rubber 21 from its surface. As a result, the sponge rubber 21 elastically deforms to fill the space between the cover 10 and the dark box 1 without any gap,
As a result, the interior of the dark box 1 in which the light-shielding device 2 and thus the stimulable phosphor stored therein is completely shielded from external light.

When the shading device 2 is mounted and the inside of the dark box 1 is shielded from the external light by further closing the dark box cover 10, the cover attaching / detaching device 4 installed in the dark box 1 is operated and the table 3 is placed on the table 3. The light blocking cover 13 of the light blocking device 2 is automatically removed from the phosphor base 12. As is clear from the above description, the light-shielding cover 13 and the phosphor base 12 are provided.
Are connected to each other only by fitting the pressing tip 16 and the base recess 17 to each other. Therefore, if the light shielding cover 13 is separated from the phosphor base 12 with a slightly strong force, the light shielding cover 13 can be easily removed. Can be removed from.

When the light-shielding cover 13 is removed, the stimulable phosphor 11 bonded to the phosphor base 12 and carrying an X-ray latent image is exposed to the outside in the light-shielded dark box 1. In this state, the table driving device 6 is activated to operate the table 3 and the phosphor base 1 mounted on the table 3.
2 is translated in the direction of arrow A ′, and it is conveyed to the reading stage of the reading device 5.

The reading device 5 is provided with, for example, a laser light source, a laser light scanning device, and a photo-detecting device such as a photomultiplier. When the stimulable phosphor 11 is set on the reading stage of the reader 5, the laser light generated by the laser light source scans the entire surface of the stimulable phosphor 11 by the action of the laser light scanning device, and the X-ray is emitted during the laser scanning. The latent image becomes light and diverges to the outside. The divergent light is detected by the photo detector. By the above operation, the stimulable phosphor 11
The X-ray information formed within is measured.

When the above-mentioned reading process is completed, the X-ray latent image remaining in the stimulable phosphor 11 is erased, and then the table 3 is moved back in the direction A, so that the phosphor base 12 (FIG. 3). Is returned to the position below the dark box opening 8 again. Then, the light shielding cover 13 is put on the phosphor base 12 again by the cover attaching / detaching device 4. After that, the dark box cover 10 is opened to open the dark box opening 8, and the shader 2 is taken out of the dark box 1 by the measurer. Shading device 2
The post-processing for the above, for example, the erasing processing of the X-ray latent image remaining in the stimulable phosphor 11 may be performed in another place other than the dark box 1 after taking out the light blocking device 2.

As described above, the black light-shielding film 15 shown in FIGS. 1 and 3 prevents the stimulable phosphor 11 from being exposed to light when the stimulable phosphor 11 is stored, and further during X-ray imaging. X-rays are transmitted. In the present embodiment, the following two types of film members are used as the black light-shielding film 15 having such an effect. One is a simple carbon film formed of only carbon and containing no pulp fiber or the like. This carbon simple substance film is a thin film material formed by forming a polymer material into a thin film shape and subjecting it to carbonization treatment. The other is a carbon-containing polyimide resin film. This resin film is a thin film material formed by bonding fine carbon powders with a polyimide resin. Usually, a polyimide resin is obtained by polycondensation of an aromatic tetrabasic acid and an aromatic diamine.

Each of the carbon simple substance film and the carbon-containing polyimide resin film has (1) a sufficient light-shielding function for visible light, (2) little X-ray absorption, and (3) X-ray. It has a property that the scattering intensity is small and no particular diffraction peak is exhibited or it is extremely small.

FIG. 8 shows an X-ray optical system used in an experiment conducted to examine the X-ray absorption coefficient and the X-ray scattering state of the light shielding film member. This X-ray optical system includes an X-ray source 31 using a copper target, a divergence slit 32, a Si (101) crystal 33, a scattered radiation blocking slit 34, a light receiving slit 35, and a monochromator 36.
And the X-ray detector 37.
The light-shielding film member S to be measured was placed between the light-receiving slit 35 and the monochromator 36. The light-shielding film members used for the measurement are three types, which are a conventionally used light-shielding film, black paper, a carbon simple substance film, and a carbon-containing polyimide resin film. The black paper is a membrane member manufactured by mixing pulp fibers and carbon powder and making them with a paper machine.

The X-ray absorption coefficient of the light shielding film member was measured from the intensity change of the diffraction line of the Si crystal 33 when the light shielding film member S was placed and when it was removed. The light-shielding film member S was measured with two types, one and two.
Further, the diffraction line intensity was obtained by integrating the count values for 10 seconds 10 times and taking the average value thereof. The results obtained by this measurement are shown in Table 1. As is apparent from Table 1, the X-ray absorption coefficients of the carbon simple substance film and the carbon-containing polyimide resin film are much smaller than those of the conventional black paper. Therefore, if the black light-shielding film 15 (FIG. 3) is formed using them, the stimulable phosphor 11
It is possible to form a clear X-ray image by suppressing the amount of attenuation of X-rays transmitted through the black light shielding film 15 at the time of X-ray exposure.

The measurement of the X-ray scattering state of the light shielding film member is carried out by the method shown in FIG.
In the above optical system, Si33 is held in a fixed state, and the slits 34, 35, the light shielding film member S, the monochromator 36, and the X-ray detector 37 are integrally rotated by 2θ,
It was performed by detecting the X-rays transmitted through the light shielding film member S. The measurement results were obtained as X-ray diffraction patterns shown in FIGS. 5, 6 and 7. FIG. 5 shows an X-ray diffraction pattern when a simple carbon film is used as the light shielding film member S, FIG. 6 shows an X-ray diffraction pattern when a carbon-containing polyimide resin film is used, and FIG. 7 shows a conventional black paper. ing. The curve P in each diffraction pattern represents a diffraction pattern due to air scattering when the light shielding film member S is not interposed. As can be seen from the diffraction patterns, in the black paper (FIG. 7), the diffraction peak Q is generated near 2θ = 20 ° and a large amount of scattered X-rays are generated, whereas the carbon simple substance film (FIG. 5). In the carbon-containing polyimide resin film (FIG. 6), such a diffraction peak does not occur or is extremely small, and the amount of scattered X-rays is kept low over the entire 2θ range. Therefore, if the black light-shielding film 15 (FIG. 3) is configured by using them, scattered X-rays are not generated much from the black light-shielding film 15 itself when the stimulable phosphor 11 is exposed to X-rays. An X-ray image can be formed inside the stimulable phosphor 11. When a conventional black paper is used, an unnecessary X-ray image is formed in the stimulable phosphor 11 due to scattered X-rays generated from the black paper itself, and an accurate X-ray image originally desired is obtained. There is a risk that it will not be obtained.

The X-ray imaging / reading system shown in FIGS. 1 to 4 is a system illustrated for convenience of understanding the structure and handling of the shading device for the X-ray photosensitive member according to the present invention. The shading device according to the present invention can be applied to a system having any structure other than that system.

[0030]

[Table 1]

[0031]

According to the present invention, a clear and accurate X-ray image can be picked up on an X-ray photosensitive member such as a stimulable phosphor. Further, in the manufacturing process, it is difficult for pinholes to occur in the black light-shielding film, and it is not necessary to frequently perform an exposure test as in the case of using conventional black paper.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a light shielding device for an X-ray photosensitive member according to the present invention.

FIG. 2 is a perspective view showing an entire X-ray imaging / reading system including the light shielding device.

FIG. 3 is an exploded perspective view showing a part of the light shielding device for the X-ray photosensitive member.

FIG. 4 is a side sectional view showing a pressing tip for fixing a cover used in the light shielding device.

FIG. 5 is a graph showing a result of an X-ray scattering measurement experiment performed on a carbon simple substance film used as a material of a black light shielding film.

FIG. 6 is a graph showing the results of an X-ray scattering measurement experiment conducted on a carbon-containing polyimide resin film used as a material for a black light shielding film.

FIG. 7 is a graph showing the results of an X-ray scattering measurement experiment performed on a black paper that has been conventionally used as a black light shielding film.

FIG. 8 is a schematic configuration diagram of an X-ray optical system used for performing the above X-ray scattering measurement.

[Explanation of symbols]

 2 Light-shielding device for X-ray photosensitive member 11 Storage phosphor 15 Black light-shielding film

Claims (2)

[Claims] 1. A light-shielding device for an X-ray photosensitive member, wherein the X-ray photosensitive member is covered with a black light-shielding film so as to be shielded from external light, and a polymer material is formed into a thin film and carbonized. A light-shielding device for an X-ray photosensitive member, characterized in that the black light-shielding film is composed of a carbon simple substance film which is a thin film material formed by rubbing. 2. An X-ray photosensitive member shading device in which an X-ray photosensitive member is covered with a black light-shielding film so as to be shielded from external light, and is formed by bonding carbon fine powders with a polyimide resin. A light-shielding device for an X-ray photosensitive member, wherein the black light-shielding film is composed of a carbon-containing polyimide resin film.