JPH03255400A - Non charged intensifying screen for x-ray photograph - Google Patents

Abstract

PURPOSE:To improve protection performance of electrical charging by containing fine particles of a metal oxide of which main constituent is Zn, Ti, Sn, Al, Mg, Ba, W or V, and of a composite of the oxides, into an intesifying screen for X-ray photograph to which a fluorescent layer coated with a protection layer, is provided. CONSTITUTION:An intensifying screen of which carrier body is provided with a fluorescent layer coated with a protection layer on it, and contains fine particles of at least one kind of metal oxides of which main constituent is Zn, Ti, Sn, Al, Mg, Ba, W or V, or composite oxides of aforemetioned metals. Thickness of the layer of the intensifying screen varies according to sensitivity of the intensifying screen to radioactivity, kinds of the fluorescent body and so on, and it is preferable that the thickness is selected from a range of 10 to 1000 mum in case that no binder is contained by a vacuum evaporation forming, and more preferable to be selected from a range of 20 to 800 mum. With those constitution, a non charged intensifying screen having a high electrical charging performance, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intensifying screen for X-ray photography, and more particularly to an intensifying screen for medical X-ray photography that is antistatically charged;

[Background of the invention]

When taking medical X-ray photographs, in order to convert the wavelength of X-rays that have passed through the subject into the wavelength range that silver halide photosensitive materials are sensitive to, the X-rays are first absorbed by a phosphor screen.
It is exposed to light according to the intensity of fluorescence in the sensitive wavelength range generated by the radiation stimulation, and an X-ray image is created by development processing.

The phosphor screen may be an intensifying screen for direct photography depending on the application.
.

There are fluorescent screens for indirect photography (generally called intensifying screens) and fluorescent screens for indirect photography (fluorescent screens, generally called fluorescent screens), in which a phosphor that emits fluorescence when exposed to X-rays is coated on a support that does not interfere with X-ray photography. Generally, a further formed phosphor layer is covered with a protective layer.

An intensifying screen is an X-ray film used for photography, and a photosensitive layer is 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 in a fluorescent screen. has a leaded glass on the camera side to block X-rays.

Both the intensifying screen and the fluorescent screen allow X-rays to pass through an object such as a human body and become an image X-ray flux having a pattern of intensity and weakness, and the image X-ray flux stimulates the phosphor particles in the core layer absorbed by the phosphor layer. The X-ray film generates fluorescence and becomes an image fluorescent flux, and the X-ray film is exposed to the image fluorescent flux to form a fixed image.

The properties required of the intensifying screen include sensitivity for efficient image conversion, luminous properties such as length of afterglow, and durability.

Furthermore, a property necessary for an intensifying screen is non-static property.

Silver halide photographic material (hereinafter simply referred to as film)
In particular, high-sensitivity films such as those for X-rays are extremely susceptible to discharge stimulation of charged charges caused by friction or peeling, and images are damaged by the generation of so-called static marks. Efforts have been made. However, it has not yet reached a satisfactory level.

In addition, in medical X-ray photography, an intensifying screen converts the X-rays that pass through the human body into light and prints it onto the film, so the quality of the image depends on how closely the X-ray film is attached to the intensifying screen. do. Therefore, of course shooting monocassettes is X! Even in TVs and chest changers, sufficient attention is paid to the adhesion. However, if the adhesion is improved, static electricity may be generated when removing the film from a cutter or the like. In particular, this phenomenon occurs frequently in winter in Japan. The static electricity generated when the film is peeled off from the intensifying screen may cause the photosensitive film to fog up, resulting in so-called static marks, which may pose a serious problem in diagnosis.

Frictional charging occurs not only during the separation charging but also during the operation of the intensifying screen until the intensifying screen is brought into close contact with the film, and static marks are created on the film due to this charging.

Therefore, in addition to the insufficient non-charging properties of the film itself, charging failures from the intensifying screen will accumulate, making it difficult to make the intensifying screen itself non-charging.

[Purpose of the invention]

An object of the present invention is to provide a non-static intensifying screen with good antistatic performance in a medical X-ray imaging system.

[Structure and effects of the invention]

The object of the present invention is to provide an intensifying screen for X-ray photography in which a phosphor layer coated with a protective layer is provided on a support using Zn.

Ti, Sn, A2. Si, Mg, Ba, M
This is achieved by an intensifying screen for X-ray photography characterized by containing at least one kind of fine particles of a metal oxide mainly composed of O, W, or (2) or a composite oxide of said metal.

In the embodiment of the present invention, non-stoichiometric oxides lacking oxygen atoms or oxides containing a small amount of foreign atoms that act as donors of metal oxides are preferable to regular stoichiometric oxides, and even in an amorphous state, crystalline fine powder is preferable. But that's fine.

Examples of metal oxides include ZnO, Tie, 5nO1
゜A et al. o3. tn＊o,, StJ, MgO,Ba
d, MoJ, VsOi, etc., or composite oxides thereof, particularly ZnO, Tie.

and SnO are preferred. Examples involving different atoms include:
For example, for ZnO, addition of Al, In, etc., SnO
For TiO2, it is effective to add Sb, Nb, halogen elements, etc., and for TiO2, it is effective to add Nb, Ta, etc. The amount of these different atoms added is 0.01 to 30 mo1
%, particularly preferably 1%.

The metal oxide fine particles of the present invention have electrical conductivity, and have a volume resistivity of 10 7 Ω·cm or less, particularly los Ω·am
It is preferable that it is below.

These oxides are described in JP-A-55-143431, JP-A-56-120519, JP-A-58-62647, and the like.

Furthermore, as described in Japanese Patent Publication No. 59-6235, it is also possible to use a conductive material in which the above metal oxide is attached to other crystalline metal oxide particles or fibrous materials (for example, titanium oxide). good.

The usable particle size is preferably 10 μm or less, but
When the diameter is 2 μm or less, the stability after dispersion is good and it is easy to use.

In addition, in order to minimize light scattering, the thickness of 0.5 μm was
It is very preferable to use the following conductive particles because they become transparent and do not cause any loss in the amount of generated light.

In addition, if the conductive material is acicular or fibrous, its length is 3
The length is preferably 0 μm or less and the diameter is 2 μI or less, particularly preferably the length is 25 μm or less, the diameter is 0.5 μm or less, and the length/diameter ratio is 3 or more.

Further, the present invention can contain conductive polymer compounds, and these compounds include, for example, polyvinylbenzenesulfonic acid salts, polyvinylbenzyltrimethylammonium chloride, U.S. Pat. No. 4,108.802, U.S. Pat.
No. 31, No. 4.126.467, No. 4,137.21
Quaternary salt polymers described in No. 7, U.S. Special Fraud 4.870,
Polymer latexes described in No. 189, 0LS2,830.767, etc. are preferred.

The metal oxide or conductive polymer compound of the present invention is used by being dispersed or contained in a binder.

Examples of binders include hydrophilic colloids such as proteins such as gelatin, colloidal albumin, and casein; cellulose compounds such as carboxymethyl cellulose and hydroxyethyl cellulose; sugar derivatives such as agar, sodium alginate, and starch derivatives; synthetic hydrophilic colloids such as polyvinyl alcohol, poly N-hinylpyrrolidone,
Examples include polyacrylic acid copolymers, polyacrylamides or their derivatives and partially hydrodispersed products, dextran, polyvinyl acetate, polyacrylic esters, rosin, and the like. Mixtures of two or more of these colloids may be used if necessary.

Among these, gelatin is the most used, and gelatin here refers to so-called lime-processed gelatin, acid-processed gelatin, and enzyme-processed gelatin. In addition to being able to replace part or all of gelatin with synthetic polymeric substances, so-called gelatin derivatives, i.e. functional groups contained in molecules such as amino groups, imino groups, hydroxyl groups or carboxyl groups, can be replaced with groups that can react with them. It may be used in place of a reagent treated or modified with a reagent having one or a graft polymer to which molecules of a polymeric substance are bonded.

The volume ratio of the metal oxide 0 according to the present invention to the binder B is 0/
Using a dispersion of B-5/95 to 40/60, 0.05 to 4 g/m'', preferably 0.1=l, is applied onto the phosphor layer.
g/112.

Various polymeric materials can be used as the support for the intensifying screen of the present invention.

Furthermore, materials that can be processed into sheets or webs that are flexible in handling are preferred; from this point of view, plastics such as cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, and polycarbonate film are preferred. Films are preferred.

In addition, the layer thickness of these supports varies depending on the material of the support used, etc., but for boat fishing it is 80μIn-1000μm, and from the viewpoint of handling, it is preferably 80μIn~1000μm.
It is 500 μm.

The surfaces of these supports may be smooth or matte for the purpose of improving adhesion to the phosphor layer.

Furthermore, these supports may be provided with an undercoat layer on the surface on which the phosphor layer is provided for the purpose of improving adhesion to the phosphor layer.

Examples of the phosphor used in the present invention include conventionally known CaWO4, Gdz02SiTb, ZnSiAg, etc.
No. 115685, Special Publication No. 55-33560, No. 58-
Phosphors disclosed in No. 2640, etc., or Japanese Patent Application Laid-open No. 48-8
No. 0487, No. 51-29889, No. 54-4788
No. 3, No. 57-148285 and No. 58-80488
A phosphor is used as disclosed in No. 1, et al.

Specific examples of phosphors used in the intensifying screen of the present invention include YzOxS: Tb, Gd, O, S: Tb, La
zOzS: Tb-(Y, Gd)zOzS: Tb, c
y, ca), o2s: Tb, Tm, YzO2S:Eu
, Gd2O,5: Eu, (Y, Gd)202S: E
uS Y, O,: Eu.

Gd, 03: Eu1 (Y, Gd)! O: E
u, YVO4: Eu1 YPO4: Tb.

GdPO,: Tb, LaPO,: Tb,
YPO, : Eu, La0Br : T
b.

La0Br: Tb, Tm, La0Br:
Ce% La0CI2: Tb, LaO+,
Q: Tb, Tm, La0CQ: Ce, G
d0Br: Tb, Gd0CI2: Tb
.

CaWOj, CaWO: P b s M g
WOi Ba5O4: Pb s-BaS 04
"Eu" (Ba, 5r) So, : Eu", Ba
5CPO*)x: Eu” (Ba.

5r)s(pot)2: Eu”, BaFC(2: E
u”, BaFBr: Eu”BaFCR: Eu”,
Tb, BaFBr: Eu”, Tb% BaF2.B
aCJl,.

KCQ: Eu”, BaF,, BaCQ2.BaSO
4, KC (1: Eu” (Ba, Mg) Fl, BaCQ
2. KCff: Eu”, Csl: NaS Cs
l: T(2°Nal, ZnS: Ag, (Zn, C
d) S: Ags ZnS: Cu, ZnS: Cu
.

kQ, (Zn, Cd)S: Cu, (Zn, Cd)S:
Cu, Al, (Zn, Cd)S: Au, Aff,
HfP2O7: Examples include X-ray phosphors such as Cu.

The average particle size of the phosphor used is o, i-iooμm1, preferably 1 to 30 μm, taking into consideration the sensitivity and granularity of the phosphor. These phosphors may be used in combination.

In the intensifying screen of the present invention, the above-mentioned phosphor is applied by a vapor deposition method such as vapor deposition or by being dispersed in a suitable binder. As the binder, there may be used a binder commonly used for layer formation, such as proteins such as gelatin, polyvinyl butyral, polyvinyl acetate, ethyl cellulose, vinyl chloride-vinyl acetate copolymer, polyurethane, and the like. Generally, the binder is a phosphor 1
It is used in a range of 0.01 to 1 part by weight.

However, in terms of the sensitivity and sharpness that can be obtained, it is preferable to use less binder, and from the viewpoint of ease of application, 0.
A range of 0.03 to 0.2 parts by weight is more preferred.

The layer thickness of the phosphor layer of the intensifying screen of the present invention varies depending on the sensitivity of the intensifying screen to radiation, the type of phosphor, etc., but it is 10 am to 1000 μm when formed by vapor deposition and does not contain a binder.
m, more preferably selected from the range of 20 μm to 800 μm, and 10 μm when containing a binder.
m to 1000 μm, more preferably 50 μm to 500 μm
m, more preferably selected from the range of 90 μm to 300 μm.

The material for the protective layer used in the present invention preferably has moisture resistance, such as cellulose acetate, polycarbonate, polyvinyl acetate, polyacrylic acid, polymethacrylic acid, polyethylene terephthalate, polyethylene, polychloride, etc. Examples include vinyl, polyamide (nylon), polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and polystyrene.

Furthermore, thermosetting resins or photocuring resins such as epoxy resins, alkyd resins, amine resins, unsaturated polyester resins, polyurethane resins, and silicone resins may be used.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples.

Example 1 (1) A slurry-like coating liquid was prepared by mixing 20w% of calcium tungstate, 2wt% of polyvinyl butyral as a binder, and 78vt% of butyl acetate. Next, a white pigment-mixed polyethylene terephthalate film (support, thickness 2.5 mm) was placed on a glass plate.
This coating liquid was applied uniformly onto the surface (0 μm) using a doctor blade. After coating, the support on which the coating film was formed was placed in a dryer, and the temperature inside the dryer was gradually raised from 25° C. to 100° C. to dry the coating film.

In this way, a phosphor layer having a layer thickness of approximately 180 μm was formed on the support.

A transparent protective film is formed by adhering a transparent film of polyethylene terephthalate (thickness: 12μ11 coated with a polyester adhesive) onto this phosphor layer with the adhesive layer side facing downward, and a transparent protective film is formed on the support. , an intensifying screen for medical X-ray photography (s-1) composed of a phosphor and a transparent protective film
)It was created.

After forming a phosphor layer on the support in the intensifying screen S-1, a gelatin solution containing the compounds of the present invention shown in Table 1 was uniformly applied. Thereafter, a transparent protective film of polyethylene terephthalate was formed in the same manner as intensifying screen S-1, and medical intensifying screens S-2 to 5-14 were created.

(2) The intensifying screen obtained in antistatic performance test (1) and the medical X-ray film manufactured by Konica Corporation; Type A was conditioned for 2 hours in a dark room at a temperature of 23°C and a relative humidity of 20%. . Thereafter, the intensifying screen and the film were brought into close contact with each other, and after rubbing it five times with a rubber roller, the film and the intensifying screen were instantly peeled off. The film was processed using developer XD-90 (manufactured by Konica Corporation) and automatic processor KX-5.
00 (manufactured by Konica Corporation). Static marks generated on the film thus obtained were visually evaluated. The results obtained are shown in Table 1. Here, the static mark was evaluated as follows.

5: No total heat is generated.

4: Very little occurrence.

3: Occurred in 1/3 of the sample.

2: Occurred in 273 samples.

table 1 In this way, intensifying screens as shown in Table 2 were prepared.

A static mark test similar to that in Example 1 was conducted using these intensifying screens. However, as a film type A
Instead, MG (manufactured by Konica 0) was used.

Example 2 (2) Creation of ortho-intensifying screen for medical X-ray photography In Example 1, instead of calcium tungstate, (, d,
o, S: An ortho intensifying screen was created using Tb (T-1). Further, as in Example 1, it can be seen that the sample of the present invention has excellent static mark properties.

hand Continued Supplementary Positive book Heisei December 25, 2017

Claims (1)

[Claims] An intensifying screen for X-ray photography, which has a phosphor layer covered with a protective layer on a support, contains Zn, Ti, Sn, Al, Si, Mg,
An intensifying screen for X-ray photography, characterized in that it contains at least one type of fine particles of a metal oxide containing Ba, Mo, W, or V as a main component, or a composite oxide of the metal.