JP2006329860A - Radiographic image conversion panel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a radiographic image conversion panel that obtains the whole physical properties of a photostimulable phosphor film and always satisfies a certain quality level. <P>SOLUTION: In this manufacturing method of the radiographic image conversion panel, the photostimulable phosphor film is formed on a predetermined substrate (step S1), and ultra-short ultraviolet rays are radiated to the photostimulable phosphor film to make the photostimulable phosphor film instantaneously emit light and to form a latent image on the photostimulable phosphor film, phosphor light instantaneously emitted is detected, then photostimulable exciting light is radiated to the photostimulable phosphor film to stimulably emit light, and phosphor light stimulably emitted is detected(step S2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiographic image conversion panel used for forming a radiographic image of a subject and a manufacturing method thereof.

  Conventionally, radiographic images such as X-ray images have been widely used for diagnosis of medical conditions in the medical field. In particular, radiographic images using intensifying screen-film systems have been developed as an imaging system that combines high reliability and excellent cost performance as a result of high sensitivity and high image quality in the long history. Used in the medical field. In recent years, computed radiography (CR (computed radiography)) using a stimulable phosphor as a main part of a radiation image conversion panel has been commercialized, and high sensitivity and improvement in image quality have been continued day and night. .

The above “stimulable phosphor” is a substance that accumulates radiation transmitted through a subject and stimulates the stored radiation to emit light at an intensity corresponding to the dose by irradiation with stimulating excitation light, etc. The radiation image conversion panel is formed in a film shape on a predetermined substrate. An example of a method for manufacturing such a radiation image conversion panel is disclosed in Patent Document 1. In the manufacturing method described in Patent Document 1, a photostimulable phosphor film is formed on a predetermined substrate, and the photostimulable phosphor film is irradiated with an electron beam such as X-rays. Is emitted instantaneously, the emission intensity of the photostimulable phosphor film is measured, and the photostimulable phosphor film is evaluated from the measurement results (see paragraphs 0041 to 0045).
JP 2004-12419 A

  However, in the evaluation of the photostimulable phosphor film in the manufacturing method described in Patent Document 1, the photostimulable phosphor film cannot be evaluated with high accuracy, and in order to satisfy certain quality standards, it is more accurate. In addition, it was necessary to quickly evaluate the photostimulable phosphor film.

  An object of the present invention is to grasp the overall physical properties of the photostimulable phosphor film and to manufacture a radiation image conversion panel that always satisfies a certain quality standard.

In order to solve the above-mentioned problem, the manufacturing method of the radiation image conversion panel according to claim 1,
A photostimulable phosphor film is formed on a predetermined substrate, and the stimulable phosphor film is irradiated with excitation light to cause the stimulable phosphor film to emit light instantaneously and to the photostimulable phosphor film. After forming a latent image and detecting the instantaneously emitted fluorescence, the stimulable phosphor film is irradiated with stimulated excitation light to cause stimulated emission, and the stimulated emission fluorescence is detected. It is a feature.

The invention described in claim 2
In the manufacturing method of the radiation image conversion panel according to claim 1,
The excitation light with which the photostimulable phosphor film is irradiated is ultra-short ultraviolet rays.

The invention according to claim 3
In the manufacturing method of the radiation image conversion panel according to claim 1 or 2,
Detecting the instantaneously emitted fluorescence and measuring the instantaneous emission amount and spectral distribution of the fluorescence,
The stimulated emission fluorescence is detected and the amount of stimulated emission of the fluorescence is measured.

The radiation image conversion panel of the invention according to claim 4 is,
It was manufactured by the manufacturing method of the radiographic image conversion panel as described in any one of Claims 1-3.

  According to the present invention, since both instantaneous light emission and stimulated light emission are detected, the photostimulable phosphor film can be reliably and rapidly evaluated. In addition, because of the use of ultrashort ultraviolet rays, it is possible to evaluate a large-sized photostimulable phosphor film, which is difficult with X-ray irradiation, and the measuring apparatus itself is smaller and less expensive than using X-rays. It can be. In addition, since the photostimulable phosphor film can be evaluated in a large size state during production before separation, defective products can be identified before the product is completed, improving work efficiency and reducing costs. It can be carried out. In addition, by evaluating the photostimulable phosphor film in a large size, it is possible to specify a pass / fail location in the photostimulable phosphor film and manufacture a product using a portion from which the defective portion is removed. The method of cutting the photostimulable phosphor film can be changed, and the photostimulable phosphor film can be used without waste. As a result, the yield rate and yield can be increased.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for carrying out the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

FIG. 1 is a cross-sectional view showing a schematic configuration of the radiation image conversion panel 1.
As shown in FIG. 1, the radiation image conversion panel 1 has a predetermined substrate 2, and a photostimulable phosphor film 3 is formed on the substrate 2.

  The substrate 2 is made of a polymer material, glass, metal, etc., and in particular, a plastic film such as cellulose acetate film, polyester film, polyethylene terephthalate, polyamide film, polyimide film, triacetate film, polycarbonate film, quartz, borosilicate It is good to be comprised by glass sheets, such as glass, chemically tempered glass, or a metal sheet which has a coating layer of metal sheets, such as aluminum, iron, copper, chromium, or those metal oxides.

  The photostimulable phosphor film 3 is made of a europium-activated cesium halide-based photostimulable phosphor such as CsBr: Eu, and is formed by a known vapor deposition process.

  In the radiation image conversion panel 1, a substrate 2 and a stimulable phosphor film 3 are sealed between two moisture-proof protective films 4 and 4. Specifically, the peripheral portions of the protective films 4 and 4 are fused together over the entire circumference of the substrate 2 and the photostimulable phosphor film 3, and the substrate 2 and the photostimulable phosphor film 3 are bonded to the protective film 4 and 4. 4 is completely sealed, and moisture can be surely prevented from entering the photostimulable phosphor film 3.

FIG. 2 is a block diagram showing a schematic configuration of a manufacturing system 5 for manufacturing the radiation image conversion panel 1.
As shown in FIG. 2, in the manufacturing system 5, the stimulable phosphor film 3 is deposited on the substrate 2 by depositing the stimulable phosphor film 3 to form the stimulable phosphor film 3 on the substrate 2. An activation device 20 that is chemically activated and a sealing device 30 that seals the substrate 2 on which the photostimulable phosphor film 3 is formed with a resin film are provided.

  The vapor deposition apparatus 10 is provided with a measuring device 40, which irradiates the stimulable phosphor film 3 with excitation light (ultrashort ultraviolet light in the present embodiment) and emits the stimulable fluorescence. A light emission amount and a spectral distribution of instantaneous luminescence emitted from the body film 3 are measured, and a latent image is formed by irradiating the photostimulable phosphor film 3 with the ultrashort ultraviolet ray. The phosphor film 3 is irradiated with photostimulated excitation light, and the amount of stimulated luminescence emitted from the photostimulable phosphor film 3 is measured. Here, the ultrashort ultraviolet rays refer to ultraviolet rays having a wavelength of about 1 to 200 nm. In the manufacturing system 5 of the radiation image conversion panel 1, the conditions for the vapor deposition process by the vapor deposition apparatus 10 and the conditions for the activation process by the activation apparatus 20 can be appropriately changed from the measurement result of the measurement apparatus 40. It has become.

  When ultrashort ultraviolet rays are used as excitation light, an action close to that of X-rays (having the energy to pull electrons up to the conduction band) can be obtained, and the measuring apparatus can be made smaller and less expensive than X-rays. It is easy to do, and cost and efficiency are also good. In addition, since ultra-short ultraviolet rays are not complicated, it is possible to evaluate a large-size photostimulable phosphor film, which is difficult with X-ray irradiation. Evaluation of the stimulable phosphor film can be performed. Therefore, a defective product can be specified before being completed as a product, and work efficiency can be improved and costs can be reduced. In addition, by evaluating the photostimulable phosphor film in a large size, it is possible to specify a pass / fail location in the photostimulable phosphor film and manufacture a product using a portion from which the defective portion is removed. The method of cutting the photostimulable phosphor film can be changed, and the photostimulable phosphor film can be used without waste. As a result, the yield rate and yield can be increased.

FIG. 3 is a diagram showing a schematic configuration of the vapor deposition apparatus 10 and the measurement apparatus 40.
As shown in FIG. 3, the vapor deposition apparatus 10 has a vapor deposition furnace 11. A crucible 12 is disposed inside the vapor deposition furnace 11, and a light transmissive transmission window 13 is disposed on the side of the vapor deposition furnace 11.

  The measuring device 40 includes an ultraviolet light source 41 that emits ultrashort ultraviolet light having a wavelength of about 1 to 200 nm. The ultraviolet light source 41 emits excitation light for exciting the photostimulable phosphor film 3. Specifically, in the CsBr crystal used in the photostimulable phosphor film 3 of this embodiment, the wavelength 169 is set. It emits light of around 5nm. Further, when a BaFBr crystal is used in the photostimulable phosphor film, light having a wavelength of about 150 nm is emitted. The ultraviolet light source 41 is disposed outside the vapor deposition furnace 11 and at a position facing the transmission window 13. Ultrashort ultraviolet light emitted from the ultraviolet light source 41 passes through the transmission window 13 and propagates into the vapor deposition furnace 11. It is supposed to be.

  A polygon mirror 42 is disposed inside the vapor deposition furnace 11. The polygon mirror 42 is arranged at a position where the ultraviolet light source 41 can receive the ultrashort ultraviolet light, and irradiates the photostimulable phosphor film 3 while rotating the ultrashort ultraviolet light of the ultraviolet light source 41 itself ( (See the solid line in FIG. 3). When the photostimulable phosphor film 3 receives ultrashort ultraviolet rays and emits light instantaneously, the polygon mirror 42 receives the light (fluorescence) and propagates it from the inside of the vapor deposition furnace 11 to the outside through the transmission window 13. (Refer to the dotted line in FIG. 3).

  An optical sensor 43 is disposed near the ultraviolet light source 41 and at a position facing the transmission window 13. The optical sensor 43 is a sensor that detects the fluorescence transmitted through the transmission window 13, and detects the amount of fluorescent light instantaneously emitted by the photostimulable phosphor film 3. A computer 45 is connected to the optical sensor 43, and the computer 45 measures and calculates the instantaneous emission spectrum of the photostimulable phosphor film 3 based on the detection result of the optical sensor 43.

Further, in the vicinity of the ultraviolet light source 41 and the optical sensor 43, a stimulating light that emits a stimulating light for stimulating the stimulable phosphor film 3 that has been excited by the ultrashort ultraviolet light of the ultraviolet light source 41 is shown. A light source 44 is arranged. Examples of the excitation light from the excitation light source 44 include a He—Ne laser (633 nm), a semiconductor laser (LD: 660 nm, 685 nm), and the like. The stimulable phosphor film 3 is irradiated through the polygon mirror 42 (see the alternate long and short dash line in FIG. 3). The polygon mirror 42 receives the light (fluorescence) when the stimulable phosphor film 3 receives stimulated excitation light such as an LD and receives the light (fluorescence), as in the case of the ultrashort ultraviolet rays. The light is propagated from the inside to the outside through the transmission window 13 (see the dotted line in FIG. 3).
Further, the optical sensor 43 of the present embodiment also serves as a sensor that detects the fluorescence that has been stimulated to emit light, and detects the amount of fluorescence that has been emitted by the stimulable phosphor film 3.

  The measuring device 40 includes the above-described ultraviolet light source 41, polygon mirror 42, optical sensor 43, stimulating light source 44, and computer 45, and is mainly composed of these members.

  Then, the manufacturing method of the radiographic image conversion panel 1 which concerns on this invention is demonstrated, referring FIG.

FIG. 4 is a flowchart showing an outline of a method for manufacturing the radiation image conversion panel 1.
The manufacturing method of the radiation image conversion panel 1 uses the manufacturing system 5 of the radiation image conversion panel 1 described above, and is first set in advance using a vapor deposition apparatus 10 as a stimulable phosphor film forming apparatus. The stimulable phosphor film 3 is formed on the substrate 2 under the deposited conditions (step S1).

  Specifically, as shown in FIG. 3, the substrate 2 is installed inside the vapor deposition furnace 11 of the vapor deposition apparatus 10, and the inside of the vapor deposition furnace 11 is evacuated to a vacuum state in a hydrogen halide atmosphere. Thereafter, the photostimulable phosphor film 3 is formed on the substrate 2 by evaporating the photostimulable phosphor from the crucible 12 using the photostimulable phosphor as an evaporation source by a resistance heating method, an electron beam method, or the like. .

  When the processing of step S1 is completed, the amount of emitted fluorescence and the spectral distribution of the instantaneous phosphorescent film 3 emitted by the stimulable phosphor film 3 are measured using the measuring device 40, and the fluorescent light emitted from the stimulable phosphor film 3 is stimulated. Is measured (step S2).

  Specifically, as shown in FIG. 3, in a state where ultrashort ultraviolet rays are emitted from the ultraviolet light source 41, the polygon mirror 42 is rotated to irradiate the photostimulable phosphor film 3 with the ultrashort ultraviolet rays. At this time, since the photostimulable phosphor film 3 receives ultrashort ultraviolet rays and emits light instantaneously, the fluorescence is detected by the optical sensor 43. In response to the detection result of the optical sensor 43, the computer 45 measures and calculates the light emission amount and the spectral distribution of the fluorescence instantaneously emitted by the stimulable phosphor film 3.

  Further, by irradiating the ultrashort ultraviolet light from the ultraviolet light source 41, the photostimulable phosphor film 3 emits light instantaneously and forms a latent image. Then, after measuring the amount of light emission and spectral distribution of the instantaneous light emission of the photostimulable phosphor film 3, the irradiation of the ultrashort ultraviolet rays from the ultraviolet light source 41 is stopped, and then the excitation light from the stimulating light source 44 is stimulated. (In this embodiment, a semiconductor laser) is emitted, and in this state, the polygon mirror 42 is rotated to irradiate the photostimulable phosphor film 3 with the photostimulable excitation light. At this time, the photostimulable phosphor film 3 receives photostimulated excitation light and emits photostimulated light, and the fluorescence is detected by the optical sensor 43. In response to the detection result of the optical sensor 43, the computer 45 measures and calculates the amount of fluorescence emitted by the stimulable phosphor film 3.

  In the process of step S2, the spectral distribution of the photostimulable phosphor film 3 is calculated from the detected fluorescence using the computer 45 as a calculation device, and the Eu concentration is calculated to calculate the photostimulable phosphor. The film thickness and the light emitting element amount (Eu amount) of each part of the film 3 may be calculated over the entire stimulable phosphor film 3. That is, in the process of step S2, the measuring device 40 (including the computer 45) detects fluorescence, and the computer 45 also calculates the spectral distribution, film thickness, and light emitting element amount of the stimulable phosphor film 3 from the result. You may come to do.

  When the process of step S2 is completed, it is determined whether or not the result measured and calculated in the process of step S2 satisfies a certain standard (step S3). That is, (1) whether the spectral distribution calculated in step S2 is a predetermined distribution, (2) whether the light emission amount of instantaneous light emission is a predetermined value, or (3) the light emission amount of stimulated light emission is a predetermined value. Each of them is judged.

  In the process of step S3, if it is determined that all the conditions (1) to (3) are satisfied and the result is good, the activation activity set in advance for the stimulable phosphor film 3 using the activation device 30 is used. The stimulable phosphor film 3 is activated by performing a known heat treatment, plasma treatment or the like under the crystallization conditions (step S4).

  If it is determined in step S3 that the condition (1) is not satisfied and the result is not good, step S1 is performed on the substrate 2 subsequent to the substrate 2 on which the photostimulable phosphor film 3 is formed in step S1. The vapor deposition process similar to the process of step S1 is performed under the vapor deposition conditions different from those of the process (step S5). That is, if the photostimulable phosphor film 3 is formed on the n-th substrate 2 in the process of step S1, the deposition conditions of the process of step S1 are changed, and the (n + 1) The vapor deposition process similar to the process of step S1 is performed on the second substrate 2 (the process of step S1 is replaced with the process of step S5).

  “Vapor deposition conditions” are the degree of vacuum inside the vapor deposition furnace 11, the partial pressure of hydrogen halide, the temperature of the crucible 12, the temperature inside the vapor deposition furnace 11, the temperature of the substrate 2, and the like. Then, the vapor deposition process is performed in a state where at least one of the plurality of conditions is changed.

  Furthermore, in the process of step S3, when it is determined that the condition (1) is not satisfied and the result is not good, the activation condition (previously set for the photostimulable phosphor film 3 using the activation device 30 ( The stimulable phosphor film 3 is activated by performing a known heat treatment, plasma treatment or the like under an activation condition different from the activation condition of the treatment in step S4 (step S6). That is, the activation condition set in advance is changed, and the activation process is executed under the changed activation condition.

  “Activation conditions” are heating time in heat treatment, heating temperature, plasma irradiation time in plasma processing, plasma irradiation intensity, and the like. In the process of step S6, at least one of the plurality of conditions is set. The activation process is executed in a state changed from the initial condition.

If the conditions (2) and (3) are not satisfied, an abnormality in the material surface of the photostimulable phosphor film 3 can be considered. For example, when the amount of instantaneous light emission that is the condition of (2) is not a predetermined value, there may be a case where the Eu ²⁺ amount is abnormal, which is caused by a shortage of the Eu ²⁺ amount. In addition, when the amount of instantaneous light emission that is the condition of (2) is not a predetermined value, there may be a case where the light emission is abnormal, and in this case, the crystal transparency abnormality is the cause. Furthermore, when the light emission amount of the stimulated light emission that satisfies the condition (2) but does not satisfy the condition (3) is not a predetermined value, an abnormality in a portion that forms a latent image is considered. This is because impurities are mixed into the portion forming the latent image.

  In these cases, a part that does not satisfy the condition is cut out, and a product is manufactured using only a good part that satisfies the condition. Here, the computer 45 of the measuring device 40 calculates the final product size and shape of the photostimulable phosphor film 3 to be produced based on the size and shape of a good portion, and the optimal separation without waste is performed. To be done. Thereby, the yield rate and yield of a product can be improved. Further, abnormalities in the conditions (2) and (3) are accumulated and analyzed so as to be improved in terms of material. In the case of a manufacturing system in which material conditions are included in the feedback of the manufacturing process, feedback is made so as to improve.

  When the processes of steps S4 and S6 are completed, the substrate 2 and the photostimulable phosphor film 3 are sealed between the two protective films 4 and 4 using the sealing device 30 (step S7). Thus, the radiation image conversion panel 1 can be manufactured by performing each process from step S1 to step S7.

  In the above embodiment, in the process of step S2, the fluorescence when the stimulable phosphor film 3 emits light instantaneously is detected, and the fluorescence when the stimulable phosphor film 3 emits stimulating light is also detected. Therefore, it is possible to measure the light emission amount and spectral distribution at the time of instantaneous light emission and the light emission amount at the time of stimulating light emission, and to reliably and quickly recognize the quality of the stimulable phosphor film 3 during the manufacturing process, This knowledge can be effectively used for the processing after step S3. If the quality of the photostimulable phosphor film 3 is inferior in the judgment in the process in step S3, the process is changed to a condition different from the preset condition and the processes in steps S5 and S6 are executed. It is also possible to improve the performance of the photostimulable phosphor film 3 during the manufacturing process. Therefore, it is possible to use an inexpensive material for the substrate 2 or the stimulable phosphor film 3 or the like, or to expand the range of use conditions of the vapor deposition apparatus 10 or the activation apparatus 20, etc. The radiation image conversion panel 1 that satisfies the quality standard can be manufactured.

  The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.

1 is a cross-sectional view illustrating a schematic configuration of a radiation image conversion panel 1. FIG. 1 is a block diagram showing a schematic configuration of a production system 5 for a radiation image conversion panel 1. FIG. 1 is a diagram showing a schematic configuration of a vapor deposition apparatus 10 and a measurement apparatus 40. 3 is a flowchart showing an outline of a method for manufacturing the radiation image conversion panel 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation image conversion panel 2 Substrate 3 Stimulable phosphor film 4 Protective film 5 Manufacturing system 10 Vapor deposition apparatus 20 Activation apparatus 30 Sealing apparatus 40 Measuring apparatus 41 Ultraviolet light source 42 Polygon mirror 43 Optical sensor 44 Stimulation light source 45 Computer

Claims (4)

  A photostimulable phosphor film is formed on a predetermined substrate, and the stimulable phosphor film is irradiated with excitation light to cause the stimulable phosphor film to emit light instantaneously and to the photostimulable phosphor film. After forming a latent image and detecting the instantaneously emitted fluorescence, the stimulable phosphor film is irradiated with stimulated excitation light to cause stimulated emission, and the stimulated emission fluorescence is detected. A method for producing a radiation image conversion panel. In the manufacturing method of the radiation image conversion panel according to claim 1,
A method for producing a radiation image conversion panel, wherein the excitation light applied to the photostimulable phosphor film is ultrashort ultraviolet rays. In the manufacturing method of the radiation image conversion panel according to claim 1 or 2,
Detecting the instantaneously emitted fluorescence and measuring the instantaneous emission amount and spectral distribution of the fluorescence,
A method for producing a radiation image conversion panel, wherein the stimulated emission fluorescence is detected and the amount of stimulated emission of the fluorescence is measured.   A radiation image conversion panel manufactured by the method for manufacturing a radiation image conversion panel according to claim 1.

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