JP4492288B2 - Radiation image conversion panel - Google Patents

Description

The present invention relates to a radiation image conversion panel, and more particularly, to a radiation image conversion panel including a phosphor layer formed using an alkali halide phosphor .

  Conventionally, radiographic images represented by X-ray images have been used for the purpose of disease diagnosis and the like. As a method for obtaining such a radiation image, in recent years, a radiation image reading method employing a stimulable phosphor has been proposed and put into practical use. In this method, the radiation transmitted through the subject is irradiated to the stimulable phosphor layer of the radiation image conversion panel, and radiation energy corresponding to the radiation transmittance of each part of the subject is accumulated. Then, the radiation energy accumulated by scanning the photostimulable phosphor layer with stimulated excitation light is emitted as stimulated emission light, and this stimulated emission light is converted into an image signal using a photoelectric conversion means. Thus, a radiographic image is obtained as digital image data.

As a radiation image conversion panel used in such a radiation image reading method, a radiation image conversion panel in which a photostimulable phosphor layer is formed on a support is known (for example, see Patent Document 1).
In general, photostimulable phosphors are sensitive to humidity, and their characteristics deteriorate due to moisture absorption. Therefore, the stimulable phosphor must be protected from the outside air, and this radiation image conversion panel has a structure in which a phosphor plate having a stimulable phosphor layer formed on a support is covered with a protective film. Thus, the photostimulable phosphor layer is shielded from the outside air to improve the moisture resistance.

Alternatively, when manufacturing a radiation image conversion panel by vacuum vapor deposition, the storage and handling of the material used when manufacturing the radiation image conversion panel in the stage before performing vacuum vapor deposition is defined as a dew point of 0 ° C. or less, The improvement of moisture resistance was aimed at (for example, refer patent document 2).
JP 2002-277598 A JP 2004-93243 A

  However, in either case of Patent Document 1 and Patent Document 2, since the light emission luminance of the stimulable phosphor itself is not improved, the stimulable phosphor is altered by absorbing moisture over time, and the radiation image It was insufficient to fundamentally prevent the function and performance of the conversion panel from being deteriorated.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to provide a radiation image conversion panel having excellent moisture resistance.

A radiation image conversion panel according to the invention of claim 1 is provided.
A radiation image conversion panel in which an alkali halide phosphor layer is formed in a columnar shape by a gas-phase growth method on a support provided with a light reflection layer and an undercoat layer, and is included in the support and includes water The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix eluting in the phosphor is 0.01 to 50 ppm , and the phosphor contained in the phosphor layer and the phosphor contained in the support are the same. The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the phosphor layer is 0.01 to 30 ppm .

According to the invention of claim 1,
A radiation image conversion panel in which an alkali halide phosphor layer is formed in a columnar shape by a gas-phase growth method on a support provided with a light reflection layer and an undercoat layer, and is included in the support and includes water The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix eluting in the phosphor is 0.01 to 50 ppm , and the phosphor contained in the phosphor layer and the phosphor contained in the support are the same. Since the total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the phosphor layer is 0.01 to 30 ppm , the stimulable phosphor panel is supported by The total concentration of alkali metal impurities and alkaline earth metal impurities contained in the body layer can be suppressed within a certain range.

The invention described in claim 2
The radiation image conversion panel according to claim 1 , wherein the phosphor matrix is CsBr, an alkali metal impurity other than the phosphor matrix is Na, and an alkaline earth metal impurity other than the phosphor matrix is Ca. It is characterized by.

According to the invention described in claim 2 , since the phosphor matrix is CsBr, the alkali metal impurity other than the phosphor matrix is Na, and the alkaline earth metal impurity other than the phosphor matrix is Ca, In particular, in a phosphor matrix made of CsBr, the concentrations of Na and Ca contained in the support can be suppressed within a certain range.

The invention according to claim 3
The radiation image conversion panel according to claim 1 or 2 , wherein the total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the support and eluted into water is 0.01. It is characterized by being 20 ppm or less.

According to invention of Claim 3 ,
The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the support and eluting in water is 0.01 to 20 ppm, compared with the invention according to claim 1. Thus, the photostimulable phosphor panel can further suppress the total concentration of alkali metal impurities and alkaline earth metal impurities within a certain range.

According to the first aspect of the present invention, the photostimulable phosphor panel can suppress the total concentration of alkali metal impurities and alkaline earth metal impurities contained in the support layer within such a certain range. By reducing the alkali metal impurities and alkaline earth metal impurities eluted to the support and absorbing moisture, the phosphor can be prevented from being deactivated, and the moisture resistance can be improved.

According to the second aspect of the present invention, in particular, in the phosphor matrix made of CsBr, the concentration of Na and Ca contained in the support can be suppressed within such a certain range, and thus the composition is such. The photostimulable phosphor panel can improve the moisture resistance by preventing the phosphor from being deactivated by absorbing moisture.

According to the invention described in claim 3 , compared with the invention described in claim 1, the stimulable phosphor panel further suppresses the total concentration of alkali metal impurities and alkaline earth metal impurities within a certain range. Therefore, it is possible to improve the moisture resistance by preventing the phosphor from being deactivated by absorbing moisture.

  Hereinafter, a radiation image conversion panel according to a specific embodiment of the present invention will be described with reference to FIGS. However, the scope of the present invention is not limited to the illustrated examples.

  As shown in FIG. 1, the radiation image conversion panel 1 of the present invention has a phosphor panel 4 in which a stimulable phosphor layer 3 is formed on a predetermined support 2, and the phosphor panel 4. Is completely sealed with two protective films 5 and 5.

  As the support 2 used in this embodiment, the total concentration of alkali metal impurities contained in addition to the stimulable phosphor matrix constituting the stimulable phosphor layer 3 is 0.01 to 50 ppm, preferably 0. A material in which the total concentration of alkali metal impurities existing in the support 2 is defined so as to be 0.01 or more and 20 ppm or less is used.

  Here, the alkali metal impurity refers to a compound composed of an alkali metal, an alkaline earth metal, or both, and is a compound composed of group Ia (excluding hydrogen) or group IIa or both of the periodic table of elements. Pointing. For example, in the case of a stimulable phosphor made of CsBr: Eu, it is preferable that Na or Ca or both of them are contained as alkali metal impurities.

The total concentration of alkali metal impurities present in the support 2 can be defined as the total concentration (elution amount) of alkali metal impurities eluted into water. Specifically, the amount of elution is determined by immersing the support 2 in a beaker containing pure water and measuring the total concentration of alkali metal impurities eluted in pure water after 10 minutes. The support was in units of 100 cm ² (10 cm × 10 cm).

  As described above, the total concentration of the alkali metal impurities present in the support 2 is defined by the alkali metal contained in the support 2 when the support 2 is heated when the radiation image conversion panel is manufactured. Suppression of system impurities to the surface of the support 2 is suppressed within a certain range, and the crystal structure of the photostimulable phosphor is disturbed between the support 2 and the photostimulable phosphor layer 3. This is to prevent the inactive phosphor from being deactivated.

  The support 2 is preferably made of a material having a low moisture permeability among the above-mentioned ones whose total concentration of alkali metal impurities is defined, such as a polymer material, glass or metal. In particular, cellulose acetate film, polyester film, polyethylene terephthalate, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, plate glass such as quartz, borosilicate glass, chemically tempered glass, or aluminum, iron, It is preferable to use a metal sheet such as copper or chromium or a metal sheet having a coating layer of the metal oxide.

  The surface 2a (upper surface in FIG. 1) of the support 2 may be a smooth surface, or may be a mat surface for the purpose of improving the adhesiveness with the stimulable phosphor layer 3, and on the surface 2a. May be provided with an undercoat layer for the purpose of improving the adhesion to the photostimulable phosphor layer 3, and on the surface 2 a, the support 2 is transmitted to form the photostimulable phosphor layer 3. A light reflecting layer may be provided for the purpose of preventing excitation light from entering.

  Moreover, although the layer thickness of these support bodies 2 changes with thickness of the support body 2 to be used, it is generally 80 micrometers-5000 micrometers, and it is 80 micrometers-3000 micrometers more preferably from the point on handling.

  The stimulable phosphor layer 3 has a layer thickness of 50 μm or more, preferably 300 to 500 μm, depending on the purpose of use of the radiation image conversion panel 1 and the type of stimulable phosphor.

FIG. 2 is an enlarged cross-sectional view of the phosphor panel 4.
As shown in FIG. 2, the photostimulable phosphor layer 3 has a columnar structure in which a large number of columnar crystals 3a, 3a,. Each columnar crystal 3 a may be inclined at a predetermined angle with respect to the normal line R of the surface 2 a of the support 2.

  As the photostimulable phosphor used for such photostimulable phosphor layer 3, an alkali halide photostimulable phosphor represented by the general formula (1) can be used.

M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA (1)

Here, M ¹ is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and in particular, is at least one alkali metal selected from the group consisting of K, Rb and Cs. preferable.

M ² is at least one divalent metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu, and Ni, and in particular, selected from Be, Mg, Ca, Sr, and Ba. It is preferably at least one divalent metal.

M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Al, Ga and In, at least one trivalent metal selected from the group consisting of Y, La, Ce, Sm, Eu, Gd, Lu, Al, Ga and It is preferably at least one trivalent metal selected from the group consisting of In.

  X, X ′ and X ″ are at least one halogen selected from the group consisting of F, Cl, Br and I, and particularly X is preferably at least one halogen selected from the group consisting of Br and I. .

  A is selected from the group consisting of Eu, Tb, In, Ga, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. At least one metal selected from the group consisting of Eu, Cs, Sm, Tl and Na.

a, b, and e are numerical values in the range of 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 <e ≦ 1.0, respectively, and in particular, b is in the range of 0 ≦ b ≦ 10 ⁻² It is preferable to show a numerical value.

  Among these, it is particularly preferable to have a stimulable phosphor represented by the following general formula (2).

  CsBr: eEu (2)

  Here, e represents a numerical value in the range of 0.0001 <e ≦ 1.0.

  The stimulable phosphor contains alkali metal impurities contained in addition to the matrix constituting the stimulable phosphor, the total concentration of which is 0.01 to 100 ppm, preferably 0.01 to 30 ppm. It is included as follows.

  Thus, the fact that the stimulable phosphor contains an alkali metal impurity other than the base as an impurity reduces the initial luminance of the stimulable phosphor layer 3 to be formed by adding the impurity. Even if it is, the stimulable phosphor is prevented from being deactivated due to disturbance of the crystal structure of the photostimulable phosphor due to moisture absorption of the alkali metal impurities contained in the photostimulable phosphor layer 3. Because.

  The photostimulable phosphor is manufactured by the following manufacturing method using, for example, the following phosphor materials (a) to (d).

  (A) At least one selected from the group consisting of LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CSBr, and CsI Species or two or more compounds.

(B) BeF ₂ , BeCl ₂ , BeBr ₂ , BeI ₂ , MgF ₂ , MgCl ₂ , MgBr ₂ ,
_{MgI 2, CaF 2, CaCl 2} , CaBr 2, CaI 2, SrF 2, SrCl 2, SrBr 2, SrI 2, BaF 2, BaCl 2, BaBr 2, BaI 2, ZnF 2, ZnCl 2, ZnBr 2, ZnI 2 _{, CdF 2, CdCl 2, CdBr} 2, CdI 2, CuF 2, CuCl 2, CuBr 2, CuI 2, NiF 2, NiCl 2, from NiBr ₂ and the group consisting of NiI ₂ at least one or more selected Compound.

_{(C) ScF 3, ScCl 3} , ScBr 3, ScI 3, YF 3, YCl 3, YBr 3, YI 3, LaF 3, LaCl 3, LaBr 3, LaI 3, CeF 3, CeCl 3, CeBr 3, CeI 3 _{, PrF 3, PrCl 3, PrBr} 3, PrI 3, NdF 3, NdCl 3, NdBr 3, NdI 3, PmF 3, PmCl 3, PmBr 3, PmI 3, SmF 3, SmCl 3, SmBr 3, SmI 3, EuF _{3, EuCl 3, EuBr 3,} EuI 3, GdF 3, GdCl 3, GdBr 3, GdI 3, TbF 3, TbCl 3, TbBr 3, TbI 3, DyF 3, DyCl 3, DyBr 3, DyI 3, HoF 3, _{HoCl 3, HoBr 3, HoI 3} , ErF 3, ErCl 3, ErBr 3, ErI 3, TmF 3, TmCl 3, TmBr 3, TmI 3, YbF 3 _{YbCl 3, YbBr 3, YbI 3} , LuF 3, LuCl 3, LuBr 3, LuI 3, AlF 3, AlCl 3, AlBr 3, AlI 3, GaF 3, GaCl 3, GaBr 3, GaI 3, InF 3, InCl 3 , InBr ₃ , and In
At least one or two or more compounds selected from the group consisting of I ₃ ;

  (D) From the group consisting of Eu, Tb, In, Ga, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. At least one or two or more metals selected.

  The phosphor materials of the above (a) to (d) are weighed so as to satisfy the ranges of a, b and e in the general formula (1) and mixed with pure water. In mixing, it is preferable to mix thoroughly using a mortar, ball mill, mixer mill or the like.

As a method for adjusting the total concentration of alkali metal impurities, the precision of purification may be adjusted, or a small amount may be added to a phosphor material with high purity. When a trace amount is added, the alkali metal is adjusted so that the total concentration of alkali metal impurities contained other than the matrix constituting the photostimulable phosphor is 0.01 to 100 ppm, preferably 0.01 to 30 ppm. The phosphor raw material is weighed and mixed in consideration of the total concentration of system impurities. For example, when producing a photostimulable phosphor made of CsBr: Eu, NaBr or CaBr ₂ or both of them may be mixed as an alkali metal impurity.

  Thus, the total concentration of alkali metal impurities contained in the phosphor raw material is defined, and the alkali metal impurities contained in the stimulable phosphor layer 3 are controlled by controlling the alkali metal impurities within a certain range. It suppresses moisture absorption of impurities and prevents the stimulable phosphor from being deactivated due to disorder of the crystal structure of the stimulable phosphor.

  Next, a predetermined acid is added so that the pH value C of the raw material mixture obtained by mixing the phosphor raw materials is adjusted to 0 <C <7, and then water is evaporated.

  Next, a raw material mixture obtained by evaporating and evaporating water from the raw material mixture is filled in a heat-resistant container such as a quartz crucible or an alumina crucible and fired in an electric furnace.

  Next, the obtained raw material mixture is filled in a heat-resistant container such as a quartz crucible or an alumina crucible and fired in an electric furnace. The firing temperature is preferably 500 to 1000 ° C. The firing time varies depending on the filling amount of the raw material mixture, the firing temperature and the like, but is preferably 0.5 to 6 hours.

  The firing atmosphere includes a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide gas atmosphere containing a small amount of carbon monoxide, a neutral atmosphere such as a nitrogen gas atmosphere and a rare gas atmosphere, or a small amount of oxygen gas. A weak oxidizing atmosphere is preferred.

  After firing once under the above firing conditions, the obtained fired product is taken out from the electric furnace and pulverized, and then the fired product powder is again filled in a heat-resistant container and placed in the electric furnace, and the same firing as described above. Re-firing under the conditions can further increase the luminous brightness of the photostimulable phosphor, and when the fired product is cooled from the firing temperature to room temperature, the fired product is taken out of the electric furnace and allowed to cool in the air. The desired photostimulable phosphor can also be obtained by this, but it may be cooled in the same weak reducing atmosphere, neutral atmosphere or weak oxidizing atmosphere as in the firing.

  In addition, by moving the fired product from the heating part to the cooling part in an electric furnace and quenching in a weakly reducing atmosphere, neutral atmosphere or weakly oxidizing atmosphere, the resulting stimulable phosphor is excited. The light emission luminance can be further increased.

  In the radiation image conversion panel according to the present invention, the photostimulable phosphor layer 3 is formed on one surface of the support 2 by the vapor deposition method using the photostimulable phosphor thus produced. It is manufactured by. As the vapor deposition method, a vacuum deposition method can be used.

  In the vacuum deposition method, for example, the support 2 is installed in a conventionally known deposition apparatus, and after the stimulable phosphor is installed in a conventionally known deposition source, the interior of the deposition apparatus is evacuated and evacuated. The stimulable phosphor is heated and evaporated to deposit the vapor on the surface of the support 2 in the form of a thin film, and the stimulable phosphor layer 3 formed by forming a layered structure has a desired thickness. Grow.

  At this time, there are no particular limitations on the vapor deposition method and vapor deposition conditions, which may be appropriately selected according to the layer thickness of the intended stimulable phosphor layer 3 and the speed at which the stimulable phosphor layer 3 is formed.

  Therefore, the vapor deposition source and its heating means are not particularly limited, and may be electron beam (EB) heating using an electron gun or the like, resistance heating, or induction heating. Further, a plurality of vapor deposition sources may be provided for vapor deposition.

  Further, the output of the heating means is not particularly limited, and may be appropriately selected according to the speed at which the photostimulable phosphor layer 3 is formed.

  Moreover, as a preferable example of the vapor deposition method and vapor deposition conditions, vapor deposition while heating the support 2 can be mentioned. At this time, the temperature of the support 2 may be set to 50 ° C. to 400 ° C., and is preferably 100 ° C. to 250 ° C. in terms of the characteristics of the stimulable phosphor. Considering the heat resistance of the film, it is preferably 50 ° C to 150 ° C, more preferably 50 ° C to 100 ° C.

Further, the surface of the support 2 shines at a speed of about 0.05 μm / min to 300 μm / min while keeping the inside of the vapor deposition apparatus at a vacuum of 1.0 × 10 ⁻⁵ Pa to 1.0 × 10 ⁻² Pa. It is possible to grow the stimulable phosphor layer 3.

FIG. 2 is a diagram showing a state in which the photostimulable phosphor layer 3 is formed on the support 2 by vapor deposition.
The incident angle of the vapor flow of the stimulable phosphor with respect to the normal direction (R) of the surface of the support 2 fixed to the support holder 6 that supports the support ₂ is θ ₂ (60 ° in the figure). Assuming that the angle of the columnar crystal 3a with respect to the normal direction (R) of the support surface is θ ₁ (30 ° in the figure), empirically θ ₁ is about half of θ ₂ , and the columnar crystal 3a is formed at this angle. Is done. Note that θ ₁ is preferably 0 ° or more and 60 ° or less, and more preferably 0 ° or more and 30 ° or less.

  In addition, the gap formed between the columnar crystals 3a may be filled with a filler such as a binder, and in addition to reinforcing the stimulable phosphor layer 3, a highly light-absorbing substance and a highly light-reflecting substance may be used. It may be filled. In addition to providing the reinforcing effect, this is effective in reducing the light diffusion in the lateral direction of the stimulated excitation light incident on the stimulable phosphor layer 3.

  At this time, on the surface 2a of the support 2 on which the photostimulable phosphor layer 3 is formed, the alkali metal contained in the support 2 is defined by defining the concentration of alkali metal impurities contained in the support 2. The system impurities are prevented from eluting to the surface 2a of the support 2 by heating the support 2 within a certain range, the crystal structure of the stimulable phosphor is disturbed, and the stimulable phosphor is deactivated. There is no end.

  Further, in the photostimulable phosphor layer 3, the alkali metal impurities contained in the photostimulable phosphor layer 3 absorb moisture by defining the concentration of alkali metal impurities contained in the photostimulable phosphor. This prevents the stimulable phosphor from being deactivated by disturbing the crystal structure of the stimulable phosphor.

  After the photostimulable phosphor layer 3 having a desired thickness is provided through such a process, the phosphor panel 4 is taken out from the vapor deposition apparatus 6 and the taken-out phosphor panel 4 is sandwiched between two protective films 5. The periphery is heated and fused with an impulse sealer and sealed. Thereby, manufacture of the radiation image conversion panel 1 is completed.

  When sealing, the protective film 5 may be simply attached to the support 2 so as to cover the stimulable phosphor layer 3 to complete the production of the radiation image conversion panel 1.

  In this way, a radiation image conversion panel containing an alkali metal impurity defined at a certain concentration as described above is produced in the stimulable phosphor layer and the support of the radiation image conversion panel. This prevents the stimulable phosphor from being deactivated due to disturbance of the crystal structure of the body.

  As described above, in the radiation image conversion panel of the present invention, the total concentration of alkali metal impurities other than the phosphor matrix contained in the support 2 and the photostimulable phosphor layer 3 formed on the support 2 are provided. By defining the total concentration of alkali metal impurities other than the included phosphor matrix, it is possible to prevent the stimulable phosphor from being deactivated due to moisture absorption by the stimulable phosphor. Therefore, it can have excellent moisture resistance, such as suppressing a decrease in light emission luminance even in a high humidity environment.

  Hereinafter, the present invention will be described with reference to examples. In addition, this invention is not limited by these Examples. In the examples, according to the method described below, a sample No. assuming a radiation image conversion panel was used. 1 to sample no. 3 and sample no. 5 Sample No. No. 7 and a sample No. assuming a radiation image conversion panel as a comparative example. 4 and sample no. 8 was prepared, and the relative luminance deterioration rate of each sample was measured and evaluated.

<Preparation of sample>
(1) Sample No. Production of 1 Using a glass substrate having a size of 10 cm × 10 cm, a square shape and a thickness of 2 mm, a support having a Na concentration of 1 ppm contained in the support was prepared as follows.

  First, a light reflecting layer is provided on one surface of the glass substrate. After that, a silicone resin to which NaBr is added is applied onto the light reflection layer with a known bar coater so as to have a thickness of 1 μm so that the Na elution amount is 1 ppm, and an undercoat layer is provided. In the following description, a glass substrate provided with a light reflecting layer and an undercoat layer on a glass substrate is referred to as a support, and in this example, Na is eluted from the undercoat layer, but is eluted from the support itself. Is also envisaged.

  Thereafter, a phosphor having a photostimulable phosphor layer formed on the light reflecting layer of the support was vapor-deposited on the light reflecting layer of the support by vapor deposition of a stimulable phosphor based on CsBr. A body plate was formed.

  Specifically, first, CsBr (manufactured by Kanto Chemical Co., Ltd.) and NaBr (manufactured by Kanto Chemical Co., Ltd.), which are raw materials of the stimulable phosphor, are included in the stimulable phosphor layer formed on the support. NaBr is added and mixed so that the Na concentration becomes 1 ppm, and dissolved in pure water to obtain a raw material mixture. Next, the water in the raw material mixture is evaporated to obtain a raw material mixture, and then the raw material mixture is baked at 800 ° C. for 60 minutes to obtain a fired product. Thereby, the Na concentration in the fired product is adjusted. Next, vapor deposition is performed using this fired product. First, the fired product is filled into a deposition source in a vacuum chamber of a deposition apparatus.

After that, the support is fixed with the surface of the support on which the light reflecting layer is formed facing the vapor deposition source, and the vacuum chamber is evacuated to 1 × 10 ⁻⁵ Pa, and then Ar gas is introduced. The vacuum degree in the vacuum chamber was adjusted to 1 × 10 ⁻² Pa.

  Thereafter, the support is heated to 100 ° C., the deposition source is heated in a state where the support is held, CsBr is deposited on the support, and a stimulable phosphor layer having a 1 mm thick columnar structure is formed on the light of each support. After forming on the reflective layer, the vapor deposition was finished, and after cooling, the phosphor plate was taken out and used as Sample 1.

(2) Sample No. Sample No. 2 1 except that when mixing the raw materials of the stimulable phosphor, NaBr was added and mixed so that the concentration of Na contained in the stimulable phosphor layer formed on the support was 30 ppm. In the same manner as in the above (1), the produced phosphor plate was used as a sample No. 2.

(3) Sample No. Sample No. 3 1 except that when mixing the raw materials of the stimulable phosphor, NaBr was added and mixed so that the concentration of Na contained in the stimulable phosphor layer formed on the support was 80 ppm. In the same manner as in the above (1), the produced phosphor plate was used as a sample No. It was set to 3.

(4) Sample No. As a comparative example, sample No. 4 was prepared. 1 except that when mixing the raw materials of the photostimulable phosphor, NaBr was added and mixed so that the concentration of Na contained in the photostimulable phosphor layer formed on the support was 200 ppm. In the same manner as in the above (1), the produced phosphor plate was used as a sample No. It was set to 4.

(5) Sample No. Sample No. 5 The phosphor plate produced in the same manner as in (2) above except that vapor deposition was performed using a support having a Na concentration of 5 ppm in the support and the support used was changed. Sample no. It was set to 5.
In addition, the preparation method of the support body to be used is sample No. 1 was prepared in the same manner as in (1) except that NaBr was added and the silicone resin was applied onto the light reflection layer so that the amount of Na eluted was 5 ppm.

(6) Sample No. Sample No. 6 In the production of 2, the phosphor plate produced by the same method as in (2) above, except that vapor deposition was performed using a support having a Na concentration of 30 ppm contained in the support, and the support used was changed. Sample no. It was set to 6.
In addition, the preparation method of the support body to be used is sample No. 1 was prepared in the same manner as in (1) except that NaBr was added and the silicone resin was applied onto the light reflecting layer so that the Na elution amount was 30 ppm.

(7) Sample No. Preparation of Sample No. 7 In the production of 2, the phosphor plate produced by the same method as in (2) above, except that vapor deposition was performed using a support having a Na concentration of 45 ppm contained in the support, and the support used was changed. Sample no. It was set to 7.
In addition, the preparation method of the support body to be used is sample No. 1 was prepared in the same manner as in (1) except that NaBr was added and the silicone resin was applied onto the light reflection layer so that the Na elution amount was 45 ppm.

(8) Sample No. As a comparative example, sample No. 8 was prepared. The phosphor plate produced in the same manner as in (2) above except that vapor deposition was performed using a support having a Na concentration of 100 ppm in the support and the support used was changed. Sample no. It was set to 8.
In addition, the preparation method of the support body to be used is sample No. 1 was prepared in the same manner as in (1) except that NaBr was added and the silicone resin was applied onto the light reflecting layer so that the Na elution amount was 100 ppm.

<Evaluation of sample>
(1) Measurement of relative luminance deterioration rate under high humidity environment Sample No. 1 to sample no. 8 After irradiating X-rays with a tube voltage of 80 kVp from the side on which the photostimulable phosphor layer of each sample was formed, the panel was excited by scanning with He-Ne laser light (633 nm). The stimulated luminescence emitted is received by a photoreceiver (photoelectron image multiplier of spectral sensitivity S-5), and the emission intensity is measured. Note that. The light emission intensity at this time is called initial luminance. Thereafter, each sample is left in a room kept at 40 ° C. and 80% humidity for 1 hour to cause deterioration due to humidity. Thereafter, the emission intensity (the luminance after deterioration) was measured again, and the relative luminance deterioration rate (%), which is the luminance after deterioration with respect to the initial luminance, was determined for each sample and listed in Table 1 below.

As can be seen from Table 1, as the concentration of Na contained in the phosphor layer increases, the relative luminance deterioration rate increases. In particular, Sample No. in which the Na concentration contained in the phosphor layer is 1,30,80 ppm. . 1 to sample no. 3 shows that the relative luminance deterioration rate is within 0 to 8%, and the relative luminance deterioration rate is hardly lowered even in a high humidity environment, and excellent humidity resistance is exhibited.
Further, it can be seen that when the Na concentration contained in the support is also increased, the luminance deterioration rate is increased. 2 and sample no. 5 Sample No. 7 shows that the luminance deterioration rate is within 3 to 9%, and the relative luminance deterioration rate is hardly lowered even in a high humidity environment, and excellent humidity resistance is exhibited.

It is typical sectional drawing of the radiographic image conversion panel to which this invention is applied. It is typical sectional drawing of the fluorescent substance layer of the radiographic image conversion panel to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation image conversion panel 2 Support body 3 Stimulable phosphor layer 4 Phosphor panel 5 Protective film

Claims (3)

A radiation image conversion panel in which an alkali halide phosphor layer is formed in a columnar shape by a gas-phase growth method on a support provided with a light reflection layer and an undercoat layer, and is included in the support and includes water The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix eluting in the phosphor is 0.01 to 50 ppm , and the phosphor contained in the phosphor layer and the phosphor contained in the support are the same. A radiation image conversion panel , wherein the total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the phosphor layer is 0.01 to 30 ppm .   The radiographic image according to claim 1, wherein the phosphor matrix is CsBr, an alkali metal impurity other than the phosphor matrix is Na, and an alkaline earth metal impurity other than the phosphor matrix is Ca. Conversion panel.   The total concentration of alkali metal impurities and alkaline earth metal impurities other than the phosphor matrix contained in the support and eluted in water is 0.01 or more and 20 ppm or less. The radiation image conversion panel according to 2.

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