JPS60173500A - Screen for x-ray photograph and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to an intensifying screen for direct imaging or a fluorescent screen for indirect imaging of medical X-ray photography, and a method for manufacturing the same. (Prior art) Intensifying Nuclean for direct imaging
(commonly called intensifying screen) and fluorescent screen for indirect photography (fluorescent screen)
A phosphor plate (generally called a phosphor plate) is made by coating a phosphor that emits fluorescence with X-rays on a support that does not interfere with X-ray shadowing, and then coating the formed phosphor layer with a protective layer. That's what he overturned. The X-ray film used for photography has photosensitive layers coated on the front and back sides of the film support, so the intensifying screen is applied to each photosensitive layer to increase the light receiving efficiency, and the fluorescent plate In order to block X radiation, a leaded glass is installed on the camera side. 7. The intensifying screen and the fluorescent plate (hereinafter collectively referred to as the screen) produce an image X-ray flux having a pattern of intensity when X-rays pass through a subject such as a human body. ``The image X-ray flux stimulates the phosphor particles in the phosphor layer and generates fluorescence to become an image fluorescence flux, and the X-ray film is exposed to the image fluorescence flux to act as an intermediary to form a sand image. In the conventional screen having the above-mentioned structure, the irradiation caused by the phosphor particle surface in the phosphor layer and the halation at the layer interfaces of the insulating layer, the support, etc. The fluorescent light spreads out relatively thickly, causing
The sharpness and contrast of images produced on the ray film are reduced. To prevent harmful effects caused by light scattering such as irradiation and halation, Japanese Patent Application Laid-Open No. 55-67700 discloses that a fluorescent substance is installed in a large number of small compartments made by intersecting a large number of partition members that absorb or reflect fluorescent light. A method of independent filling is disclosed. The disclosed method attempts to improve sharpness by restricting the spread of light emitted by the phosphor using a partition member, but according to studies by the present inventors, the screen manufactured according to the disclosed method does not It became clear that a decrease in sensitivity occurred. In addition, since it is difficult to form lobules of sufficient depth depending on the material of the partition wall member, it is possible to take measures to increase the sensitivity by making the lumen deeper and thickening the phosphor layer. The first object of the present invention is to provide a screen that can produce a fluorescent image on the phosphor layer surface and an X-ray image or a dye image on the lumen surface with good sharpness without causing a decrease in sensitivity. It is to provide. A second object of the present invention is to provide a screen having a honeycomb structure of partition members, which is free from restrictions on the materials used to form the partition members. Furthermore, a third object is to provide a method for manufacturing a screen that satisfies the above objects. (Structure of the Invention) The objects of the invention described above are as follows: (1) A honeycomb structure consisting of a large number of lobes separated by partition members, each of which is filled with a fluorescent material. X to make the light layer
An X-ray photographic screen characterized in that the phosphor layer is a layer made of a rare earth phosphor, and (2) a partition wall member υ (- Honeycomb consisting of many locules (k+ol+ey co
mb) A method for manufacturing an X-ray photography screen having a phosphor layer filled with fluorophores each having a structure, characterized in that a rare earth phosphor is used as the phosphor. The present invention is satisfied by a method for manufacturing an X-ray photographic screen. The present invention will be explained in detail below. Figures 1 and 2 are
1 shows one embodiment of the screen of the present invention. 10 is a fluorescent support substrate, 11 is a protective plate, and 12 is a partition member for forming a cell having a thickness wl and a volume hlXd, Xd. As shown in FIG. 2, the partition wall member 12 has a structure in which a large number of partition wall members are joined to form a large number of cells. The shape of the small chamber 13 is not limited to the shape shown in FIG. 2, but may be circular as shown in FIG. It may also have a curved shape. Furthermore, the arrangement of the locules 13 is not limited to the arrangement shown in FIG. 2, but may be another arrangement as shown in FIG. 3, or any other arrangement as long as it is divided into one locule. good. Each of these cells is filled with a rare earth phosphor 14 to form a phosphor layer 15. In addition, the substrate 0 can be any material that transmits, absorbs, or reflects the emitted light of the phosphor.
A material that reflects emitted light is more preferable because it increases the sensitivity. Note that in order to make the substrate JO absorbing or reflecting emitted light, the substrate 10 itself does not need to have these properties, and a emitted light absorbing layer or an emitted light reflecting layer may be provided on the surface of the substrate. It may be formed by a method such as coating or vapor deposition. The wall surface of the cell 13 formed by the partition wall member 12 may have absorbency or reflectivity for emitted light, and even if the base material of the partition wall itself does not have these properties. Alternatively, an emitted light absorbing layer or an emitted light reflecting layer may be formed on the wall surface of the cell by coating or vapor deposition. In addition, when a material with good X-ray absorption is used as the partition member 12, in particular, a metal or a matched metal suitably arranged for X-ray absorption, such as a laminated structure of metals obtained by metals, alloys thereof, plating, etc., is used. Scattered X-rays scattered in the object are absorbed by the partition wall member] 2, and the amount of scattered X-rays can be reduced. Therefore, there is no need to use a grid for removing scattered X-rays, and X-ray imaging becomes easier. . In the screen having such a configuration, the emitted light from the phosphor 14 travels in all directions due to scattering by the phosphor particles, but the emitted light directed toward the partition member 12 is not applied to the wall surface of the partition member 12. be absorbed or reflected by physical-optical properties. Similarly, the emitted light directed toward the substrate 0 is absorbed or reflected by the substrate. Therefore, the spread of the light emitted by the phosphor due to the X-rays irradiated to one point on the screen is limited, and a radiographic image with good sharpness can be obtained without reducing sensitivity due to the low luminous efficiency of the rare earth phosphor. is obtained. The dimensions d, +tl11hl of the lumen filled with the phosphor are determined approximately by the size determined by setting the image quality required for the screen system. That is, as a guideline, d, , d is 10 μm to 6
00I'm N The thickness width W of the partition wall is 10 to 300ttm
and depth. (In other words, the thickness of the material plate used as the material for the partition wall members constituting the honeycomb structure) is set to about 30 #m to 1000 μm, which is balanced in terms of both production and performance, and compared to the conventional method using phosphors. This provides improved performance compared to other screens. As shown in FIG. 4, in the screen of the present invention, even if the phosphor is made higher than the partition wall member 12 and the phosphor is formed uniformly in appearance, the height from the partition wall h2 If is small, the image quality will be slightly lower than that in the case where the partition wall surface and the phosphor surface are the same as shown in FIG. 1, but an image quality improvement effect close to that of FIG. 1 will be obtained. Further, even when the surface of the phosphor is lower than the upper surface of the partition wall as shown in FIG. 5, the same effect of improving image quality as in the case of FIG. 1 can be obtained. Furthermore, even when the partition wall member is included in the phosphor layer as shown in FIG. 6, the same image quality improvement effect as shown in FIG. 4 can be obtained. Examples of materials that can be used for the phosphor support substrate IO of the screen of the present invention include various UK molecular materials, glass, cool,
Items made from a single layer of material such as cotton, paper, or metal may be used, but are limited to those listed above (
jNo. Furthermore, the phosphor support substrate jO need not be limited to one type of glaze material, but may be made of two or more glaze types. These phosphor support substrates 10 may have an undercoat layer adhesive to the phosphor on the surface in contact with the phosphor in order to more firmly hold the phosphor layer. Examples of materials used for the partition members include various polymeric materials containing pigments or dyes that are opaque to emitted light, glass, ceramics, metals, etc. Metals include not only single metals but also alloys, that is, 1
It may also be a mixture of a seed metal and one or more metals or non-metals. In addition, the partition wall member may be surface-treated to a depth of Φ, or a layer may be formed of two or more materials, but in consideration of workability, price, Fe-C alloy, When considering the effect of removing scattered X-rays, pb is preferable. However, the material of the partition member used in the screen according to the present invention is not limited to the above-mentioned materials. Rare earth phosphors used in the screen of the present invention include Y20J: Tb% Gd201S: Tb
% La101B :'rb % (Y + Gd)
1028”, Tb z (Y + Gd) 102
8: 'rb +Tm %Y102S: Eu N
Gd2028: Eu z (Y +' Gd)
tows: Eu %Y, O,: Eu % Gd, 0
1:Eus, (YtGd)20. :Eu%
YVO4: Eu% ypo4: 'rb% GdP
O4: TbN LaPO4: Tb% YPO4
:Eu-s La0Br :Tb5LaOBr :
Tb+Tms La0Br :Tm5LaOC4! :
Tb-I La0Cl: Tb+Tms La0(J
:Tms La0Br :Ce, La0(J:Ca
, Gd0Br:TbXGaocl:'rbMBaSO
4: Eu'', (Ba, Sr) 804: Eu''+
, Bmg(PO4)琶2+Eu"+,BaFCA':Eu-I BaFBr:
EuzBaFCl:Eu. Tb % BaFBr: Eu t Tb % Ba
F, + BaC6R, KCI: Eu-5BaF
1 t BaCl21 BaSO4j KCl: Eu
”, (Ba+Mg)Ft 1Ba(Jt + KCl:
Eu”% (Ba+Sr)s(PO4)g :E
The average particle size of the phosphor used is preferably 0.1 to 100111nz, taking into consideration the sensitivity and granularity of the phosphor. A particle size of 1 to 30 μm is used. However, a particle size larger than the lobule formed by the partition member is not preferred. In the screen of the present invention, the above-mentioned phosphor is generally attached to a suitable binder. The binding agent may be a protein such as gelatin, a polysaccharide such as dextran, or gum arabic, polyvinyl butyral, polyvinyl acetate, nitrohyulose, ethyl cellulose, etc. , vinylidene chloride-vinyl dioxide copolymer, polymethyl methacrylate), vinyl mide-vinyl acetate copolymer, polyurethane, cellulose acetate phthalate, polyvinyl alcohol, etc. may be used. Generally, the amount of binder is 0.01 to 1
However, in terms of the screen sensitivity and sharpness obtained, the binder is less

[0.03 to 0.02 is preferable, considering the ease of application.
The range of heavy i parts is more preferable. Furthermore, in the screen of the present invention, the externally exposed surface of the phosphor layer (phosphor support substrate) is generally made of a material such as dichlorocellulose, ethylcellulose, cellulose acetate, polyester, polyethylene terephthalate, etc. 7) FFL crotch/G material is used. The thickness of the protective layer formed from such material is 0.01~
3ollrIL1 is particularly preferably 1 to 8 μm. As a method for manufacturing a partition wall member having a honeycomb structure according to the present invention, an fM manufacturing method by etching matching metal plates will be described first. For example, a photosensitive resin AZ-1350 sold by Silaplay Co., Ltd., is uniformly coated on both sides of a nickel plate as a matching metal plate. Next, a mask having an island-like pattern in the light-transmitting portion is brought into close contact with both surfaces of the nickel plate so that the front and back patterns are aligned, and exposed to ultraviolet light. After exposure, this photosensitive resin is printed. σ) The exposed areas of the photosensitive resin are washed away by development. Next, the nickel plate is baked at 120 DEG C. for 30 minutes, and then the nickel plate is etched with acid to form a partition wall member. In addition, a screen with very fine pores can be produced by methods such as temporary punching of gold or drilling holes using a carbon dioxide laser. Next, a manufacturing method (molding method) for forming a No Nikamui structure using a matrix will be explained. First, as shown in FIG. 7, a matrix having the same shape as the phosphor support substrate shown in FIG. 1 is prepared. This matrix is made of silicon crystal material and has a flat surface as shown in FIG. A ura with a width and depth of Wl l h4, which is slightly larger than h, is formed by a diamond blade. Next, a molding agent is poured into this mold. This molding agent is made of white silicone rubber containing titanium dioxide as a pigment, and after finishing, almost no emitted light passes through the partition walls, has good fluidity during molding, has excellent mold releasability, and has good shrinkage. A material with a small amount of After the molding agent has solidified, it is released from the matrix to form a partition member. Next, a manufacturing method in which a material plate is formed by erosion will be explained. For example, when using a photosensitive resin, first apply a mask with an island-like pattern on the opaque part to the light. Believe me,
Violet evening eyes that include wavelengths in the photosensitive wave range 250-400 nm! Irradiate with a). After exposure, develop this A&9 resin.
! 14). In the case of the photosensitive resin, the non-exposed area is 6 (6) and the partition wall member is formed as shown in Figure 8. haj
Since the light is bright, a light absorber or a light reflector 26 is coated or deposited on the inner surface of the partition wall of the locule as shown in FIG. Next, the method for manufacturing the screen of the present invention will be explained. First, a Hoto layer film is formed separately and placed in a horizontal V (-1).Next, after adhering the partition member to the north of this protective layer film, a phosphor dispersed in a suitable binder is applied (-1 and then It is manufactured by adhering the supporting substrate.Also, as a variation of this manufacturing method, the partition wall member of the phosphor supporting base & Co/Main φI is closely attached horizontally, and an appropriate binder is applied. It is manufactured by forming a protective layer wave film on the edge coated with a phosphor dispersed in an agent.In the screen having the configuration shown in Fig. 6, the partition member is tightly attached to the phosphor support substrate. The screen of the present invention is manufactured by applying and drying the above-mentioned phosphor coating liquid before applying the phosphor coating liquid, and then applying the phosphor coating liquid again to the partition wall member on the adhesion edge to form a protective layer. As shown in FIG. The present invention will be explained with examples.Example 1 A partition member made by etching nickel is placed on a transparent protective film of polyethylene terephthalate with a thickness of about 6 μm which was formed separately.The size of the locule of this member is d, =
d, = 120 μm, z hl = 190 μm, and the thickness of the partition wall was approximately 1 μm at its minimum. Next, 8 parts by weight of a Gd, O, S: Tb phosphor with an average particle size of 5 μm and polyvinyl butyral (resistance>ff agent) were added.
] Parts by weight were mixed and separated using cyclohegisanone (solvent) to prepare a phosphor coating solution. The phosphor coating solution was coated on the protective film at a rate of approximately 4G wry/cr.
A phosphor layer is formed by coating the phosphor layer uniformly so as to give a thickness of 200 μm, and leaving it to stand day and night.Furthermore, a polyethylene tere/phthalate support with a thickness of about 200 μm is adhered to the phosphor layer, and an intensifying screen is formed. I got admission. Separately, an intensifying screen B A' was obtained in the same manner as described above except that the partition wall member described above was not used. Further, an intensifying screen C was obtained in the same manner as described above except that CILWO4 was used as the phosphor. In addition, sensitization and MD were obtained in the same manner as above except that the nickel wall member was not used and CaWO4 was used as the phosphor. Next, we cover the fluorescent spectral range of the phosphor. can receive light. 1, Sea urchin'' 2 Intensifying screens A and B were each covered with ortho and type X-ray photographic films, and each of the above 1sm papers C and D was covered with L/Gular type Xm photographic film. However, the tube voltage is 100 TCVp z 'Gl
After irradiating the film with X-rays at a current of 100 mA for 06 seconds through an aluminum step wedge, the film was developed to determine sharpness and sensitivity. Table 1 shows imported products. Note that the sharpness is determined by the spatial frequency D2. At M1'F in O book/1111, the sensitivity is compared with Jjs on the X-ray certificate required to achieve optical 0 (and fog +1.0) on the film, and j:I photosensitive paper is 10
It is shown as a relative value with 0. Table 1 From Table 1 above, it is clear from the comparison between intensifying screen B and intensifying screen that merely using a rare earth phosphor increases sensitivity but does not improve sharpness. From a comparison between intensifying screen C and intensifying screen R, it is clear that the honeycomb structure lowers the sensitivity. However, the intensifying screen according to the present invention has significantly increased sensitivity and improved sharpness compared to the conventional intensifying screen with a honeycomb structure (intensifying screen C), and because it has a honeycomb structure, it can produce images without decreasing sensitivity. It is temporary. Example 2 A partition wall member made by chemically etching photoresist on the surface of PB alloy foil (PB 95 ES, Si 20) was
Polyethylene terephthalate of Am J♀ is placed on a support. The size of the locule of this member is d, = d, 08
04m111h1=120μm and the thickness of the partition wall is Wl
= additional μm. Then, (YO. 5+ Gd) with an average particle size of 4.5 μm
O. 5) tols: 'rb fluorescent fluorescent material 8 to 5 1
Mix and disperse polyvinyl butyral heptadone and polyvinyl butyral 1 (i) using cyclohegisanone to prepare a phosphor coating solution, and coat the phosphor coating solution on the support at a rate of approximately 30 tries/cH.
After coating and drying, a protective layer with a thickness of about 6μ7n was provided to obtain an intensifying screen E. On the other hand, apart from this, the phosphor is CaWO4 K L=%
An intensifying screen F was obtained in the same manner as above except that the weight of the phosphor coating was changed to 60' rv/ctlt. Next, for the above +g paper E, I used Orthotype
υShakai film is used closely, tube voltage 90 KVp% tube'
After irradiating the film with an X-head for 0.10 seconds at an Id current of 100 mA, the film was developed and evaluated for sharpness and sensitivity. The result is 1
It is shown in Table 2. In Table 2, the sharpness is the MTF value at a spatial frequency of 2.0 lines/angle, and the sensitivity is the intensifying screen F at 300
It is expressed as a relative value. Table 2 As is clear from Table 2 above, it can be seen that the sharpness of the photosensitive paper according to the present invention is significantly improved without decreasing the sensitivity.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the intensifying screen of the present invention, Fig. 2 is a plan view of Fig. 1, Fig. 3 is a plan view showing another 5AM example of the invention, Figs. 5 and 2116 are cross-sectional views showing embodiments of the pond of the present invention. FIG. 7 is a 1417-sided view of the matrix used for manufacturing the screen shown in FIG. 1. FIG. 8 is a cross-sectional view of a phosphor layer substrate made using a photosensitive resin. DESCRIPTION OF SYMBOLS 10... Fluorescent material support substrate 11... Mutual protection layer 12... Partition member 14... Fluorescent material 15... Fluorescence Representative Patent Attorney Noguchi 1 Parent-in-law Figure 1 Figure 2 Figure 3 Figure 4 112 5R1

Claims (2)

[Claims] (1) An X-ray photographic screen having a phosphor layer formed by filling each lobule with a phosphor in a honeycomb structure consisting of a large number of lobes separated by partition members. An X-ray photographic screen characterized in that the phosphor layer is a layer made of a rare earth phosphor. (2) A method for manufacturing an X-ray photographic screen having a phosphor layer formed by filling each lobule of a honeycomb structure with a phosphor in a honeycomb structure consisting of a large number of lobes separated by partition members, wherein A method for manufacturing an X-ray photographic screen, characterized in that a rare earth phosphor is used as a light body.