JP2012108052A - Radiation image photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect deterioration of the inside of a radiation image photographing device.SOLUTION: A radiation image photographing device (20, 20A to 20C) comprises: a scintillator (74) for converting radiation to visible light; a light detection substrate (72) for converting the visible light to an electric signal; and a light source (78) capable of selectively irradiating the light detection substrate (72) with at least two lights having different peak wavelengths. In this case, the light source (78) can irradiate the light detection substrate (72) with one light of the at least two lights as a reset light, and irradiate the light detection substrate (72) with the other lights as lights for deterioration detection to detect deterioration of the inside of the radiation image photographing device (20, 20A to 20C).

Description

  The present invention relates to a radiographic imaging apparatus having a scintillator that converts radiation into visible light and a light detection substrate that converts the visible light into an electrical signal.

  In the medical field, a radiation image of a subject is widely acquired by irradiating a subject with radiation from a radiation source and detecting the radiation transmitted through the subject with a radiographic imaging device. In this case, the radiographic image capturing apparatus includes, for example, a scintillator that converts the radiation transmitted through the subject into visible light, and a light detection substrate that converts the visible light into an electrical signal. And a photodetector such as a photodiode capable of detecting the visible light.

  By the way, when a photodetection substrate is configured using a photodiode made of amorphous silicon (a-Si) or the like, a part of charges (electrons) converted from visible light become a-Si impurity levels (defects). Once captured, and then the charge is re-emitted due to temperature rise of the photodiode due to long-time shooting such as movie shooting, unnecessary current such as dark current is generated, and the radiographic image It may cause noise. Therefore, when the radiation is not irradiated (non-imaging), the photodiode is irradiated with reset light, and the charge is pre-filled in the impurity level, and then the visible light is irradiated when the radiation is irradiated (imaging). Patent Documents 1 and 2 propose an optical reset method for reducing the noise by preventing the converted charge from being captured by the impurity level.

  In Patent Document 1, a reflective layer provided with a plurality of pores, a scintillator, and a light detection substrate are arranged in this order, and reset light is applied to the light detection element of the light detection substrate via the pores and the scintillator. Is done. In Patent Document 2, a reflective layer, a reset light source, a scintillator, and a light detection substrate are arranged in this order, and reset light output from the reset light source is applied to the light detection element of the light detection substrate via the scintillator. The

Special table 2010-525359 gazette JP 2007-225598 A

  By the way, if the radiographic imaging apparatus is continuously used, the inside of the radiographic imaging apparatus may be deteriorated.

  For example, when the scintillator and the light detection substrate are bonded with an adhesive layer, or when the adhesive layer or the adhesive layer deteriorates due to radiation when the adhesive layer is adhered with an adhesive layer, the deteriorated adhesive layer Or there exists a possibility that the said adhesion layer may absorb the visible light converted from the said radiation with the said scintillator, and may reduce the light quantity of the said visible light which injects into the said light detection board | substrate.

  More specifically, when the scintillator is made of CsI: Tl (cesium iodide added with thallium) and the scintillator converts the radiation into visible light in a blue wavelength region, the scintillator is compared with the blue wavelength region. If the adhesive layer or the pressure-sensitive adhesive layer having high transparency deteriorates (oxidizes) and colors (yellows) upon irradiation with the radiation, the colored adhesive layer or the pressure-sensitive adhesive layer becomes visible light in the blue wavelength region. Is absorbed, and the sensitivity of the visible light in the light detection substrate is reduced.

  However, Patent Documents 1 and 2 do not propose any countermeasures against deterioration in the radiation image capturing apparatus.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a radiographic imaging apparatus that can detect deterioration in the radiographic imaging apparatus.

  In order to achieve the above object, the present invention provides a radiographic imaging apparatus having a scintillator that converts radiation into visible light and a photodetection substrate that converts the visible light into an electrical signal, the peak wavelengths of which are each other. A light source capable of selectively irradiating the light detection substrate with at least two different lights, wherein the light source irradiates the light detection substrate with one of the at least two lights as a reset light; The other light can be applied to the light detection substrate as deterioration detection light for detecting deterioration in the radiographic imaging apparatus.

  According to this configuration, it is possible to detect deterioration inside the radiographic imaging apparatus by using the light output from the light source for purposes other than optical reset for the light detection substrate. In other words, if the other light is deterioration detection light for detecting deterioration in the radiographic imaging apparatus, it is possible to reliably detect the deterioration in the radiographic imaging apparatus.

  Specifically, in the radiographic imaging device, deterioration detection may be performed by the following (1) and / or (2).

  (1) The radiographic imaging apparatus further includes an adhesive layer that adheres the light detection substrate and the scintillator, or an adhesive layer that adheres the light detection substrate and the scintillator, and the light source includes the adhesive The light detection substrate can be irradiated with the reset light or the deterioration detection light via the layer or the adhesive layer, and the deterioration detection light can be absorbed by the adhesive layer or the adhesive layer deteriorated by the radiation. And light in a wavelength range different from the wavelength range of the reset light.

  If the adhesive layer or the adhesive layer is deteriorated due to the irradiation of the radiation, the deteriorated adhesive layer or the adhesive layer is light in a wavelength region including a specific peak wavelength (for example, in the blue wavelength region). If the light detection substrate is irradiated with the light through the deteriorated adhesive layer or the adhesive layer to absorb light, the light detection substrate is absorbed by the light in the adhesive layer or the adhesive layer. The amount of the light incident on the light source should be reduced.

  Therefore, in (1), the reset light or the degradation detection light (light in the wavelength range including the specific peak wavelength) is selected from the light source to the light detection substrate through the adhesive layer or the adhesive layer. Irradiate. Thereby, if the signal level of the degradation detection light detected by the photodetection substrate is lower than the signal level before degradation, the adhesive layer or the adhesive layer is caused by the radiation irradiation. It can be immediately detected that it has deteriorated. Further, since the light source functions as a reset light source that outputs the reset light and an inspection light source that outputs the deterioration detection light, the reset light source and the inspection light source are prepared separately. There is no need.

  (2) The radiographic imaging apparatus further includes a moisture-proof protective material that seals the scintillator, and the light source detects the reset light or the deterioration detection on the light detection substrate via the moisture-proof protective material and the scintillator. The deterioration detection light can be absorbed by the moisture-proof protective material deteriorated by the radiation and has a wavelength range different from the wavelength range of the reset light.

  If the moisture-proof protective material is deteriorated due to the irradiation of the radiation, the deteriorated moisture-proof protective material may also absorb light in a wavelength region including a specific peak wavelength. If the light detection substrate is irradiated with the light via a material and the scintillator, the amount of the light incident on the light detection substrate should be reduced by the absorption of the light by the moisture-proof protective material.

  Therefore, in (2), the reset light or the degradation detection light (light in the wavelength region including the specific peak wavelength) is selected from the light source to the light detection substrate via the moisture-proof protective material and the scintillator. Irradiate. Even in this case, if the signal level of the deterioration detection light detected by the light detection substrate is lower than the signal level before deterioration, the moisture-proof protective material is deteriorated due to the radiation irradiation. Can be detected immediately. Also in (2), since the light source has the functions of a reset light source and an inspection light source, it is not necessary to prepare these light sources individually.

  Here, the photodetection substrate includes at least one photodetection element that converts the visible light into the electrical signal, and the photodetection element has the light source irradiated the degradation detection light to the photodetection element. In this case, the deterioration detection light is detected as a light detection signal, and the radiation image capturing apparatus detects the signal level of the light detection signal actually detected by the light detection element and the deterioration in the radiation image capturing apparatus. A deterioration determining unit that determines whether there is deterioration in the radiographic imaging device based on the signal level of the light detection signal in a state in which no occurrence occurs.

  Accordingly, it is possible to reliably and efficiently detect the presence / absence of deterioration in the radiation imaging apparatus (for example, deterioration of the adhesive layer, the adhesive layer, or the moisture-proof protective material due to the radiation).

  The light detection element outputs the electrical signal converted from the visible light to the deterioration determination unit as a radiation detection signal, and the deterioration determination unit outputs the radiation detection signal actually detected by the light detection element. Based on the signal level and the signal level of the light detection signal, and the signal level of the radiation detection signal and the signal level of the light detection signal in a state in which no deterioration occurs in the radiation image capturing apparatus, the radiation image You may determine the presence or absence of degradation within an imaging device.

  As a result, among the components of the radiographic imaging device, the components that cause a decrease in the level of the electrical signal detected by the light detection element (for example, the adhesive layer, the adhesive layer, the moisture-proof protection) The material or the scintillator) can be reliably identified.

  The radiographic image capturing apparatus may further include a notification unit that notifies a determination result of the deterioration determination unit to the outside. Thereby, a doctor or a radiographer grasps whether or not deterioration has occurred inside the radiographic imaging apparatus, and in addition, when deterioration has occurred, which component has deteriorated. Thus, an appropriate procedure (for example, a request for repair or replacement of the radiographic apparatus) can be promptly performed.

  In the radiographic imaging apparatus described above, the photodetection substrate, the scintillator, and the light source are sequentially arranged along the radiation irradiation direction.

  In this case, the light source may be an array of light emitting elements, a backlight, or an electroluminescence light source arranged so as to face the light detection substrate via the scintillator.

  Here, the array of the light emitting elements includes a first light emitting element that outputs light in a wavelength region including a first peak wavelength, and a wavelength region including a second peak wavelength different from the first peak wavelength. What is necessary is just to be comprised at least from the 2nd light emitting element which outputs light. For example, the first light emitting element may be a light resetting light emitting element, and the second light emitting element may be a deterioration detecting light emitting element.

In addition, the backlight includes a light guide plate disposed on the scintillator on the opposite side of the light detection substrate, and at least two light sources disposed on the side of the light guide plate and capable of outputting light having different peak wavelengths. A reflection sheet disposed so as to surround the light guide plate and the at least two light sources, and a diffusion sheet disposed on a surface of the light guide plate on the scintillator side,
The at least two light sources make light incident on the light guide plate,
The light incident on the light guide plate may be emitted from the diffusion sheet to the scintillator after repeating surface reflection between the reflection sheet and the diffusion sheet in the light guide plate.

  If the backlight is configured in this way, the at least two light sources can be arranged in the non-irradiation region of the radiation, and deterioration of the at least two light sources due to the radiation can be avoided. The at least two light sources may be light emitting diodes or cold cathode tubes.

  The electroluminescence light source may be composed of at least two light sources that are stacked along the irradiation direction of the radiation and that can output light having different peak wavelengths. In particular, if the electroluminescence light source is an organic electroluminescence light source, it is possible to reduce the thickness of the electroluminescence light source.

  Further, in the above radiographic imaging apparatus, after the scintillator is formed on the vapor deposition substrate, the tip portion of the scintillator and the photodetection substrate are bonded through an adhesive layer, or the adhesive layer is bonded through an adhesive layer. May be.

  Here, when the vapor deposition substrate is impermeable to light from the light source, after forming the scintillator on the vapor deposition substrate through a peeling layer, the tip portion of the scintillator and the light detection substrate are Adhering via the adhesive layer or adhering via the adhesive layer, and then peeling the release layer and the vapor deposition substrate from the scintillator, and placing the light source on the release surface of the scintillator Also good.

  On the other hand, when the vapor deposition substrate can transmit light from the light source, the light source may be arranged through the vapor deposition substrate.

  Further, an oblique light cut layer that cuts the visible light or light from the light source traveling in an oblique direction with respect to the radiation irradiation direction may be interposed between the light detection substrate and the scintillator. . Thereby, both the improvement of the sensitivity of the photodetection substrate with respect to the visible light and the suppression of the image blur of the radiation image can be realized.

  Further, a half mirror may be interposed between the scintillator and the light source.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to detect degradation inside a radiographic imaging apparatus by utilizing the light output from a light source for uses other than the optical reset with respect to a photon detection board | substrate. That is, if the light for purposes other than light reset is deterioration detection light for detecting deterioration in the radiographic imaging apparatus, it is possible to reliably detect deterioration in the radiographic imaging apparatus.

1 is a configuration diagram of a radiographic image capturing system using an electronic cassette (radiological image capturing device) according to the present embodiment. It is a perspective view of the electronic cassette shown in FIG. It is sectional drawing along the III-III line | wire of the electronic cassette of FIG. 4A to 4C are cross-sectional views of the main part in the vicinity of the radiation detector in the electronic cassette of FIG. 3 (electronic cassettes according to the first to third embodiments). FIG. 5A is a cross-sectional view of the main part in the vicinity of the radiation detector, and FIG. 5B is a cross-sectional view of the main part in the vicinity of the light detection substrate. 6A and 6B are cross-sectional views of main parts in the vicinity of the light detection substrate. It is principal part sectional drawing of the optical detection board | substrate vicinity. 8A and 8B are cross-sectional views of the main part in the vicinity of the scintillator and the reset light source. 9A and 9B are cross-sectional views of the main part in the vicinity of the scintillator and the reset light source. It is a graph which shows the fall of the detection amount of a photodiode by deterioration of the contact bonding layer or the adhesion layer resulting from irradiation of a radiation. FIG. 11A is a cross-sectional view of main parts in the vicinity of the scintillator and the reset light source, and FIG. 11B is a plan view of main parts of the reset light source. 12A and 12B are cross-sectional views of the main part in the vicinity of the scintillator and the reset light source. 13A is a cross-sectional view showing the formation of the scintillator on the vapor deposition substrate, FIG. 13B is a cross-sectional view showing the formation of the moisture-proof protective material, and FIG. 13C shows the adhesion or adhesion of the scintillator to the light detection substrate. It is sectional drawing shown. It is sectional drawing which shows the state which peeled the vapor deposition substrate and the peeling layer from the scintillator. It is an electrical schematic block diagram of the electronic cassette of FIG. It is a flowchart which shows the basic operation | movement of the radiography system of FIG. It is a flowchart which shows the basic operation | movement of the radiography system of FIG. It is a flowchart which shows the deterioration detection of an adhesive layer or an adhesion layer, and the deterioration detection of a scintillator. It is a flowchart which shows the deterioration detection of an adhesive layer or an adhesion layer, and the deterioration detection of a scintillator. It is principal part sectional drawing which shows the state which inserted the half mirror between the scintillator and the reset light source.

  A preferred embodiment of a radiographic image capturing apparatus according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a configuration diagram of a radiation image capturing system 10 having an electronic cassette 20 (radiation image capturing apparatus) according to the present embodiment.

  The radiographic imaging system 10 detects a radiation output device 18 that irradiates a subject 16 such as a patient lying on an imaging platform 12 such as a bed, and the radiation 16 that has passed through the subject 14 and converts it into a radiographic image. An electronic cassette 20 that controls the entire radiographic imaging system 10, a console 22 that accepts an input operation of a doctor or a radiographer (hereinafter also referred to as a doctor), and a display device 24 that displays a captured radiographic image and the like Is provided.

  Between the radiation output device 18, the electronic cassette 20, the console 22 and the display device 24, for example, UWB (Ultra Wide Band), IEEE 802.11. Signals are transmitted and received by wireless LAN such as a / b / g / n or wireless communication using millimeter waves or the like. It goes without saying that signals may be transmitted and received by wired communication using a cable.

  The console 22 is connected to a radiology information system (RIS) 26 that centrally manages radiographic images and other information handled in the radiology department in the hospital. The RIS 26 is used to comprehensively manage medical information in the hospital. A medical information system (HIS) 28 to be managed is connected.

  The radiation output device 18 includes a radiation source 30 that irradiates the radiation 16, a radiation control device 32 that controls the radiation source 30, and a radiation switch 34. The radiation source 30 irradiates the electronic cassette 20 with radiation 16. The radiation 16 irradiated by the radiation source 30 may be X-rays, α-rays, β-rays, γ-rays, electron beams, or the like. The radiation switch 34 is configured to have a two-stage stroke, and the radiation control device 32 prepares for irradiation of the radiation 16 when the radiation switch 34 is half-pressed by the doctor, and from the radiation source 30 when the radiation switch 34 is fully pressed. Is irradiated.

  As described above, the radiation output device 18, the electronic cassette 20, the console 22, and the display device 24 can transmit and receive signals. Therefore, in the radiation output device 18, the radiation switch 34 is half pressed. Sometimes, a signal indicating preparation for irradiation may be transmitted to the console 22 or the like, and then a signal indicating the start of irradiation of the radiation 16 may be transmitted to the console 22 or the like when the radiation switch 34 is fully pressed.

  2 is a perspective view of the electronic cassette 20 shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of the electronic cassette 20 shown in FIG.

  The electronic cassette 20 includes a panel unit 40 and a control unit 42 disposed on the panel unit 40. Note that the thickness of the panel unit 40 is set to be thinner than the thickness of the control unit 42.

  The panel unit 40 includes a substantially rectangular casing 44 made of a material that is transmissive to the radiation 16 (see FIG. 1), and the radiation 16 is applied to the irradiation surface 46 that is the surface (upper surface) of the panel unit 40. Is done. A guide line 48 indicating the imaging region and the imaging position of the subject 14 is formed at a substantially central portion of the irradiation surface 46. An outer frame of the guide line 48 becomes a shootable region 50 indicating an irradiation field of the radiation 16. Further, the center position of the guide line 48 (intersection where the guide line 48 intersects in a cross shape) is the center position of the imageable area 50.

  A handle 52 that can be grasped by a doctor is disposed on the side surface of the housing 44 on the control unit 42 side. The doctor can transport the electronic cassette 20 to a desired location (for example, the imaging table 12) by holding the handle 52. Therefore, the electronic cassette 20 is a portable radiographic image capturing device.

  The control unit 42 includes a substantially rectangular casing 54 made of a material that is impermeable to the radiation 16. The housing 54 extends along one end of the irradiation surface 46, and the control unit 42 is disposed outside the imageable region 50 on the irradiation surface 46. In this case, on the upper surface of the housing 54, a captured radiographic image or the like can be displayed, while a display operation unit (notification unit) 56 of a touch panel system in which various information can be input by the doctor, and various types of information for the doctor. And a speaker (notification unit) 58 that outputs the notification as sound. Also, on the side surface of the housing 54, an AC adapter input terminal 60 for charging from the outside and a USB terminal 62 as an interface means capable of transmitting and receiving information between external devices (for example, the console 22). And are provided.

  As shown in FIG. 3, a radiation detector 70 that converts the radiation 16 into a radiation image is accommodated in the housing 44.

  The radiation detector 70 includes a scintillator 74 that converts the radiation 16 that has passed through the subject 14 into fluorescence (visible light 130 shown in FIG. 8B) included in the visible light region, and a light detection substrate that converts the visible light 130 into an electrical signal. 72 and reset for performing light reset on the light detection element 94 (see FIGS. 5A to 7) constituting the light detection substrate 72 by irradiating the light detection substrate 72 with reset light 132 (see FIGS. 8A and 9B). And a light source 78. Therefore, the radiation detector 70 is an indirect conversion type radiation detector.

  The radiation detector 70 is an ISS (Irradiation Side Sampling) type radiation detector as a surface reading method in which a light detection substrate 72, a scintillator 74, and a reset light source 78 are arranged in order along the irradiation direction of the radiation 16. It is. Therefore, the electronic cassette 20 according to the present embodiment is an indirect conversion type radiographic imaging device including the ISS type radiation detector 70.

  Furthermore, in the radiation detector 70, as shown in FIGS. 4A to 4C, the scintillator 74 and the light detection substrate 72 are in close contact with each other via an adhesive layer 88a or an adhesive layer 88b that can transmit the visible light 130 and the reset light 132. I am letting.

  Here, the electronic cassette 20 according to the present embodiment can be classified into the following three examples (electronic cassettes 20 </ b> A to 20 </ b> C according to the first to third examples) according to the configuration of the scintillator 74.

  In the electronic cassette 20A according to the first embodiment shown in FIG. 4A, the scintillator 74 is, for example, CsI: Tl (not shown) via a release layer 242 on a vapor deposition substrate 240 (see FIG. 13A) that is not transparent to the reset light 132. Cesium iodide to which thallium is added) is formed as a strip-like columnar crystal structure 84 by a vacuum vapor deposition method. After the vapor deposition substrate 240 and the peeling layer 242 are peeled off, the base end portion of the scintillator 74 is formed. The columnar crystal portion 82 is disposed on the reset light source 78 side, and on the other hand, the tip portion of the columnar crystal structure 84 is incorporated into the radiation detector 70 by closely contacting the light detection substrate 72 via the adhesive layer 88a or the adhesive layer 88b. .

  In this case, each column constituting the columnar crystal structure 84 is formed along a direction substantially perpendicular to the light detection substrate 72 (the vertical direction in FIG. 4A and the irradiation direction of the radiation 16), and each column adjacent to the columnar crystal structure 84 is formed. A certain amount of gap is secured between them. Further, the scintillator 74 of CsI (CsI: Tl) has a characteristic that the columnar crystal structure 84 is weak against humidity and the non-columnar crystal portion 82 is particularly vulnerable to humidity. Therefore, polyparaxylylene resin (Parylene (registered trademark)) It is sealed with a light-transmitting moisture-proof protective material 86 made of In each drawing after FIG. 4A, the gaps between the columns in the columnar crystal structure 84 are exaggerated for ease of explanation.

  Further, the wavelength range of the visible light 130 (see FIGS. 8B and 9A) emitted by the scintillator 74 is preferably a visible light region having a wavelength of 360 nm to 830 nm, and in order to enable monochrome imaging by the radiation detector 70. More preferably, it includes a green wavelength region. In particular, in CsI: Tl, the emission spectrum when irradiated with radiation 16 is 420 nm to 600 nm, and the emission peak wavelength in the visible light region is 565 nm.

  In addition, the electronic cassette 20B according to the second example shown in FIG. 4B has the scintillator 74 in the state where the non-columnar crystal portion 82 side, which is the base end portion of the scintillator 74, is removed, the reset light source 78 and the adhesive layer 88a or the adhesive layer. It is different from the electronic cassette 20A (see FIG. 4A) according to the first embodiment in that it is disposed between the layer 88b and the electronic cassette 20A.

  In this case, for example, the scintillator 74 is vapor-deposited on a vapor deposition substrate 240 (see FIG. 13A) described later, and then the scintillator 74 is sealed with a moisture-proof protective material 86, and then the scintillator 74 is separated from the vapor deposition substrate 240. The scintillator 74 of FIG. 4B is configured by removing the non-columnar crystal portion 82 side after the front end portion side of the columnar crystal structure 84 and the light detection substrate 72 are brought into close contact with each other via the adhesive layer 88a or the adhesive layer 88b. That's fine. When the scintillator 74 is formed, the scintillator 74 may be vapor deposited on the vapor deposition substrate 240 according to the vapor deposition conditions after determining the vapor deposition conditions so that the non-columnar crystal portion 82 is not formed.

  As described above, in the second embodiment, by forming the scintillator 74 in which the non-columnar crystal portion 82 does not exist, the occurrence of light scattering in the non-columnar crystal portion 82 is avoided.

  Furthermore, in the electronic cassette 20C according to the third embodiment shown in FIG. 4C, the scintillator 74 is formed on the vapor deposition substrate 108 that is transmissive to the reset light 132, the vapor deposition substrate 108 is disposed on the reset light source 78 side, and In the first and second embodiments, the tip portion of the columnar crystal structure 84 in the scintillator 74 sealed with the moisture-proof protective material 86 is brought into close contact with the light detection substrate 72 via the adhesive layer 88a or the adhesive layer 88b. This is different from the electronic cassettes 20A and 20B (see FIGS. 4A and 4B). In the third embodiment, the non-columnar crystal portion 82 is positively formed in order to improve the adhesion between the vapor deposition substrate 108 and the scintillator 74.

  A specific method for manufacturing the electronic cassettes 20A to 20C according to the first to third embodiments will be described later.

  Here, when the adhesion between the tip portion side of the columnar crystal structure 84 and the light detection substrate 72 is enhanced, and the separation of the scintillator 74 and the light detection substrate 72 during use of the electronic cassettes 20A to 20C is to be avoided. It is only necessary to firmly bond the tip portion side of the columnar crystal structure 84 and the light detection substrate 72 using the adhesive layer 88a. Further, when considering replacement of at least one of the scintillator 74 and the light detection substrate 72 due to a failure, the tip portion side of the columnar crystal structure 84 is formed using the adhesive layer 88b that does not require the adhesiveness of the adhesive layer 88a. And the light detection substrate 72 may be adhered to each other.

  In the electronic cassettes 20A to 20C according to the first to third embodiments, the method of fixing the light detection substrate 72 and the reset light source 78 inside the housing 44 is adhesion with an adhesive, adhesion with an adhesive, or fixation. Of course, it can be fixed in the housing 44 by a known fixing method such as fixing by means. 4A to 4C show the scintillator 74 made of CsI: Tl, it may be a scintillator 74 made of GOS (gadolinium oxide sulfur). In this case, for example, the scintillator 74 may be formed by applying GOS to the light detection substrate 72 or the reset light source 78. In addition, as the scintillator 74 used in the electronic cassettes 20A to 20C, when the coloring (for example, yellowing) of the adhesive layer 88a or the adhesive layer 88b occurs due to the irradiation of the radiation 16, the colored adhesive is used. Any scintillator 74 that emits visible light 130 that is absorbed by the layer 88a or the adhesive layer 88b and that reduces the signal level of the electrical signal output from the light detection element 94 may be used.

  Next, a specific configuration of the light detection substrate 72 will be described with reference to FIGS. 5A to 7. 5A to 7, the specific configuration of the light detection substrate 72 in the electronic cassette 20A according to the first embodiment will be described as a representative example. However, the electronic cassette 20B according to the second and third embodiments, Of course, 20C can be applied by appropriately changing the configurations of FIGS. 5A to 7. 5A to 7, some components are schematically illustrated or exaggerated for ease of explanation.

  In FIG. 5A, the photodetection substrate 72 forms an array of TFTs (Thin Film Transistors) 92 as switching elements on the surface of the base 90 on the bottom plate 80 side, and a photo of a-Si or the like on the TFT 92 array. It has a structure in which a plurality of light detection elements 94 using diodes are arranged. If the light detection element 94 includes a-Si, it has a wide absorption spectrum, and the visible light 130 from the scintillator 74 can be efficiently absorbed.

  In this case, the bottom plate 80 side of the light detection substrate 72 is uneven as a plurality of light detection elements 94 are arranged on the array of TFTs 92. For example, a flattening film is formed by a flattening process using a tetrafluoroethylene resin film. It is desirable to form 96. Accordingly, the scintillator 74 of CsI: Tl is in close contact with the planarizing film 96 via the adhesive layer 88a or the adhesive layer 88b after the moisture-proof protective material 86 is applied. As described above, in the configuration of FIG. 5A, the substrate 90, the TFT 92, the light detection element 94, the planarizing film 96, the adhesive layer 88 a, or the direction along the irradiation direction of the radiation 16 (the direction from the top to the bottom of FIG. 5A) The adhesive layer 88b and the scintillator 74 are laminated in order.

  The base material 90 may be a thin-walled substrate having heat resistance enough to withstand the heat generated when the scintillator 74 is formed by vapor deposition. In this case, as the base material 90, a glass substrate is usually adopted, but other materials may be used.

That is, the photodetecting element 94 is composed of an organic photoelectric conversion material or an amorphous oxide semiconductor (for example, a-Si), an organic semiconductor material (for example, a phthalocyanine compound, pentacene, or vanadyl phthalocyanine), an amorphous oxide semiconductor (for example, When the TFT 92 is composed of a-IGZO (InGaZnO ₄ )) or carbon nanotubes, the TFT 92 and the photodetecting element 94 can be formed by low-temperature film formation. Therefore, a polyimide film, a polyarylate film, two A flexible plastic film such as an axially stretched polystyrene film, an aramid film or a bionanofiber can be used as the substrate 90.

  Here, the plastic film that can be used as the substrate 90 will be described more specifically. Polyester such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin It is preferable to employ a flexible substrate such as norbornene resin or poly (chlorotrifluoroethylene) as the base material 90. If such a plastic flexible substrate is used, the weight can be reduced, and for example, it is advantageous for carrying the electronic cassette 20 (20A).

  In addition, the base material 90 includes an insulating layer for ensuring insulation, a gas barrier layer for preventing moisture and oxygen from permeating, an undercoat layer for improving flatness or adhesion to electrodes, and the like. It may be provided.

  Further, when the base material 90 is formed using an aramid film, since aramid can be applied at a high temperature process of 200 ° C. or higher, the transparent electrode material can be cured at a high temperature to reduce resistance, and solder reflow can be performed. It is also possible to deal with automatic mounting of driver ICs including processes. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (Indium Tin Oxide) or a glass substrate, warping after manufacturing is small and it is difficult to crack. Furthermore, aramid can form the base material 90 thinner than a glass substrate or the like. The base material 90 may be formed by laminating an ultra-thin glass substrate and aramid.

  On the other hand, the bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (acetobacterium Xylinum) and a transparent resin. In this case, the cellulose microfibril bundle has a width of 50 nm and a size of 1/10 with respect to the wavelength of visible light 130, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as an acrylic resin or an epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60% to 70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3ppm-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible. The substrate 90 can be formed thinner than the above.

  On the other hand, the photodetection element 94 has a sharp absorption spectrum in the region of the visible light 130 by including the organic photoelectric conversion material, and electromagnetic waves other than the visible light 130 are absorbed by the photodetection element 94. Therefore, noise generated by the radiation 16 being absorbed by the light detection element 94 can be effectively suppressed.

  In addition, the organic photoelectric conversion material preferably absorbs visible light 130 most efficiently so that its absorption peak wavelength is closer to the emission peak wavelength of the scintillator 74. Ideally, the absorption peak wavelength of the organic photoelectric conversion material coincides with the emission peak wavelength of the visible light 130, but if the difference between the two is small, the visible light 130 can be sufficiently absorbed. Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the visible light 130 is preferably within 10 nm, and more preferably within 5 nm.

  Examples of organic photoelectric conversion materials that can satisfy such conditions include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength of quinacridone in the visible light region is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI: Tl is used as the material of the scintillator 74, the difference between the peak wavelengths may be within 5 nm. Thus, the amount of charge generated in the light detection element 94 can be substantially maximized.

  In addition, if the TFT 92 is made of an organic semiconductor material, an amorphous oxide semiconductor, or a carbon nanotube, the radiation 16 is not absorbed, or even if it is absorbed, the amount of noise remains extremely small, so that the generation of noise can be effectively suppressed. it can. In particular, if the TFT 92 is made of carbon nanotubes, the switching speed of the TFT 92 can be increased, and the TFT 92 having a low degree of absorption with respect to the visible light 130 and the reset light 132 can be formed. In addition, when the TFT 92 is constituted by carbon nanotubes, the performance of the TFT 92 is remarkably deteriorated only by mixing a trace amount of metallic impurities. Therefore, the carbon nanotubes are separated and extracted by centrifugation or the like. There is a need.

  5A, the radiation 16 that has passed through the subject 14 passes through the irradiation surface 46 (top plate) of the housing 44, the adhesive layer 88a or the adhesive layer 88b, and the photodetection substrate 72, and enters the scintillator 74. Then, in the columnar crystal structure 84 of the scintillator 74, the radiation 16 is converted into fluorescence in the visible light region (visible light 130), and the converted visible light 130 travels through the columnar portion of the columnar crystal structure 84 and adheres. Each photodetection element 94 is reached via the layer 88a or the adhesive layer 88b and the planarizing film 96 (see FIG. 8B). Therefore, each light detection element 94 converts the visible light 130 into an electric signal (analog signal) and accumulates it as an electric charge. The TFT 92 reads out the electric charge accumulated in each photodetecting element 94 as an image signal.

  The configuration in FIG. 5B is different from the configuration in FIG. 5A in that TFTs 92 and photodetecting elements 94 are alternately formed on the base material 90. In this case, a region for one pixel is constituted by one adjacent TFT 92 and one photodetecting element 94. Even in the configuration of FIG. 5B, the TFT 92 and the light detection element 94 side of the light detection substrate 72 may be uneven, so that the scintillator 74 and the light detection substrate 72 are in close contact via the adhesive layer 88a or the adhesive layer 88b. In order to improve the property, it is preferable to form the planarization film 96.

  In the configuration of FIG. 6A, an array of TFTs 92 made of a-Si, a metal reflective layer 98 made of aluminum or the like, and a plurality of light detection elements 94 are sequentially laminated on a base material 90, and light detection of a light detection substrate 72 is performed. It differs from the configuration of FIGS. 5A and 5B in that a planarizing film 96 is formed on the element 94 side. In this case, each photodetecting element 94 has a structure in which a photodetection portion 94a of a photodiode that converts visible light 130 into an electric signal is sandwiched between two electrodes 94b and 94c in the vertical direction.

  In the configuration of FIG. 6A, by providing the reflective layer 98 on the TFT 92 array, when the visible light 130 from the scintillator 74 or the reset light 132 from the reset light source 78 is incident on the light detection substrate 72, Since all of the light is reflected by the reflective layer 98 toward the light detection element 94, it is possible to avoid the occurrence of switching noise in the TFT 92 due to the incidence of the visible light 130 or the reset light 132. Further, since the reflection layer 98 reflects the visible light 130 or the reset light 132, these reflected lights are incident on the light detection unit 94a of the light detection element 94, and thus the visible light 130 incident on the light detection unit 94a. Or the light quantity of the reset light 132 increases. As a result, the sensitivity of the light detection unit 94a with respect to the visible light 130 is improved, and the light detection element 94 can be efficiently reset by the reset light 132.

  6A shows the case where the reflective layer 98 is laminated on the array of TFTs 92, instead of this configuration, the light detection elements 94 and the TFTs 92 are overlapped with each other so as to overlap the light detection elements 94. A reflective layer 98 may be formed between the array. In this case, the reflection layer 98 having substantially the same area as that of the light detection element 94 is formed in units of pixels in which one light detection element 94 is one pixel. Therefore, the visible light 130 or the reset in the reflection layer 98 is reset. The occurrence of crosstalk between the pixels due to the reflection of the light 132 can be avoided.

  6B, the TFTs 92 made of a-Si and the light detection elements 94 using the photodiodes made of a-Si are alternately formed on the base material 90, and the light shielding layer 100 is formed on the bottom plate 80 side of each TFT 92. Is further formed, and a planarizing film 96 is formed on the light-blocking layer 100 and the light-detecting element 94 side of the light-detecting substrate 72, which is different from the configuration of FIGS.

  In this case, by forming the light shielding layer 100 on the TFT 92, the visible light 130 from the scintillator 74 and the reset light 132 from the reset light source 78 travel toward the light detection element 94 even if they enter the light detection substrate 72. While light is incident on the light detection element 94, all the light traveling toward the TFT 92 is absorbed by the light shielding layer 100. Therefore, in the configuration of FIG. 6B, the visible light 130 or the reset light 132 is efficiently incident on the light detection element 94, and the occurrence of switching noise in the TFT 92 due to the incidence of the visible light 130 or the reset light 132 is reliably avoided. Can do.

  The configuration of FIG. 7 is an oblique light cut that cuts visible light 130 and reset light 132 that travel in an oblique direction with respect to the irradiation direction of the radiation 16 between the adhesive layer 88 a or the adhesive layer 88 b and the planarizing film 96. It differs from the configuration of FIGS. 5A to 6B in that the layer 102 is inserted. The oblique light cut layer 102 includes a light transmitting portion 104 made of a material that transmits visible light 130 or reset light 132 (for example, silicon resin, olefin resin, urethane resin, acrylic resin, cellulose resin, polyester resin, or polycarbonate resin). The light-shielding portions 106 made of a substance having a high absorption rate for the visible light 130 or the reset light 132 (for example, a dark-colored metal oxide, pigment, or dye) are alternately arranged along the surface (horizontal direction) of the planarization film 96. It is configured by arranging.

  In this case, the visible light 130 or the reset light 132 that has traveled within a predetermined angle with respect to the irradiation direction of the radiation 16 passes through the light transmitting portion 104 and enters the light detection substrate 72. On the other hand, the visible light 130 or the reset light 132 that has traveled obliquely beyond the predetermined angle is completely absorbed by the light shielding unit 106 and is prevented from entering the light detection substrate 72. As a result, the sensitivity of the light detecting element 94 with respect to the visible light 130 is improved, and the light resetting of the light detecting element 94 by the reset light 132 can be performed reliably and efficiently. It is possible to suppress the occurrence of the image blur of the radiation image caused.

  Note that the configurations in FIGS. 5A to 7 are examples, and the photodetection substrate 72 and the like may be configured by appropriately combining these configurations. For example, in each configuration of FIGS. 5B to 6B, the oblique light cut layer 102 may be interposed between the surface of the planarizing film 96 and the adhesive layer 88a or the adhesive layer 88b.

  Next, the specific configuration of the reset light source 78 and the characteristic functions of the electronic cassette 20 according to this embodiment using the reset light source 78 (the electronic cassettes 20A to 20C according to the first to third examples) Will be described with reference to FIGS. 8A to 12B. 8A to 12B, the case where the configuration of FIG. 5A in the electronic cassette 20A according to the first embodiment is typically described will be described, but other configurations of the electronic cassette 20A (FIGS. 5B to 7B). Of course, even the electronic cassettes 20B and 20C according to the second and third embodiments can be applied by appropriately changing the illustrated configuration. 8A to 12B, for ease of explanation, some components are schematically illustrated or exaggerated.

  When the reset light source 78 outputs the reset light 132 toward the scintillator 74 when the subject 14 is not irradiated with the radiation 16 (non-imaging), the reset light 132 is transmitted to the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b. Then, the light is incident on the light detection element 94 through the planarizing film 96. In this way, by irradiating the light detection element 94 using a photodiode made of a-Si or the like with the reset light 132, the impurity level of the photodiode is pre-filled with charges, and the radiation 16 is irradiated. At this time (at the time of photographing), it is possible to perform light reset so that charges converted from the visible light 130 by the light detection element 94 are not captured by the impurity level.

  Note that in the case of the ISS type electronic cassette 20 (20A to 20C) as in the present embodiment, the light detection substrate 72 and the adhesive layer 88a or the adhesive layer 88b are arranged along the irradiation direction of the radiation 16 inside the housing 44. Since the scintillator 74 and the reset light source 78 are arranged in this order, most of the radiation 16 is converted into visible light 130 in the scintillator 74, and the radiation 16 that passes through the scintillator 74 and reaches the reset light source 78 is It is thought that it is extremely few. Therefore, in the case of the ISS system, there is no problem that the reset light 132 is generated due to the irradiation of the radiation 16 to the reset light source 78 at the time of photographing, or even if such a problem occurs, Since the amount of the reset light 132 incident on the light detection element 94 is low, the noise generated due to the irradiation of the reset light 132 becomes a low level noise that does not affect the interpretation interpretation of the radiation image by the doctor. Expected.

  Next, characteristic functions of the electronic cassette 20 (20A) according to the present embodiment using the reset light source 78 will be described with reference to FIGS. 8A to 10.

  As described above, the scintillator 74 and the light detection substrate 72 are in close contact with each other through the adhesive layer 88a or the adhesive layer 88b having transparency to the visible light 130 and the reset light 132 (see FIGS. 4A to 7). ). In this case, if the electronic cassette 20 (20A) is continuously used, the adhesive layer 88a or the adhesive layer 88b deteriorates due to the irradiation of the radiation 16, and the deteriorated adhesive layer 88a or the adhesive layer 88b absorbs the visible light 130. As a result, the amount of visible light 130 incident on the light detection element 94 is reduced.

  For example, when the CsI: Tl scintillator 74 converts the radiation 16 into visible light 130 in the blue wavelength region, the adhesive layer 88a or the adhesive layer 88b having a relatively high transparency with respect to the blue wavelength region is irradiated with the radiation 16. More specifically, when the colorless and transparent adhesive layer 88a or the adhesive layer 88b is oxidized and yellowed by irradiation of the radiation 16, the colored adhesive layer 88a or the adhesive layer 88b becomes a blue wavelength. The visible light 130 in the region is absorbed, and as a result, the visible light 130 does not reach the light detection element 94 or the amount of visible light 130 that reaches the light detection element 94 decreases. 9A and 9B, the occurrence of yellowing in the adhesive layer 88a or the adhesive layer 88b is illustrated by hatching.

  Each time when the radiation 16 having the same dose is irradiated, the light detection element 94 detects the visible light 130 and outputs an electrical signal having a signal level (detection amount) corresponding to the amount of the visible light 130. If the signal level (detection amount) of the electric signal output from the photodetecting element 94 is compared before and after the deterioration of the adhesive layer 88a or the adhesive layer 88b (for example, when the electronic cassette 20 starts to be used), As shown in FIG. 10, the detected amount after deterioration is reduced to A1 due to absorption of visible light 130 in the colored adhesive layer 88a or the adhesive layer 88b with respect to the detected amount A0 before deterioration. To do. Accordingly, the deterioration of the adhesive layer 88a or the adhesive layer 88b due to the irradiation of the radiation 16 also decreases the sensitivity of the light detection element 94 with respect to the visible light 130.

  In the case of CsI: Tl, the peak wavelength of the visible light 130 is the wavelength of green light, but the light in the blue wavelength region including the wavelength of the green light is less likely to cause image blur of the radiographic image. Therefore, as described above, when the amount of light in the blue wavelength region incident on the light detection element 94 decreases due to absorption of light in the blue wavelength region in the adhesive layer 88a or the adhesive layer 88b, the image quality of the radiation image is relatively Decreases and image blur is likely to occur.

  As described above, if the adhesive cassette 88a or the adhesive layer 88b is colored (yellowed) and continues to use the electronic cassette 20, a high-quality and high-sensitivity radiation image suitable for doctor's interpretation diagnosis is acquired. It becomes difficult. Accordingly, the deterioration of the adhesive layer 88a or the adhesive layer 88b due to the irradiation of the radiation 16 is reliably detected, and the detection result is notified to a doctor or the like, so that the electronic cassette 20 having the deteriorated adhesive layer 88a or the adhesive layer 88b can be promptly provided. It is desirable that repair or replacement (adhesion by a new adhesive layer 88a or adhesive layer 88b) can be performed.

  In particular, in the ISS type electronic cassette 20, the light detection substrate 72, the adhesive layer 88 a or the adhesive layer 88 b, the scintillator 74, and the reset light source 78 are arranged in this order along the irradiation direction of the radiation 16. Always passes through the adhesive layer 88a or the adhesive layer 88b before reaching the scintillator 74. Therefore, if the electronic cassette 20 is continuously used for radiographing the subject 14, the radiation 16 is irradiated to the adhesive layer 88a or the adhesive layer 88b every time the radiographing is performed. Therefore, the adhesive layer 88a or the adhesive layer 88b due to the radiation 16 irradiation. Deterioration (yellowing due to oxidation) is easily promoted, and the sensitivity of the visible light 130 in the light detection element 94 is significantly reduced due to the deterioration of the adhesive layer 88a or the adhesive layer 88b.

  Therefore, in the electronic cassette 20 (20A) according to the present embodiment, the reset light source 78 functions as a light reset light source that irradiates the reset light 132 to the light detection element 94 via the adhesive layer 88a or the adhesive layer 88b. Also, it has the function of an inspection light source that irradiates the adhesive layer 88a or the adhesive layer 88b with the light for detecting the deterioration of the adhesive layer 88a or the adhesive layer 88b.

  Specifically, the reset light source 78 is a light emitting diode (LED) 3 or the like on the substrate 140 disposed on the bottom plate 80 of the housing 44 so as to face the adhesive layer 88a or the adhesive layer 88b and the light detection element 94. It is comprised by arrange | positioning the light emitting elements 142a-142c of a kind alternately.

  The light emitting element 142a is a red light source that emits red light 132a toward the adhesive layer 88a or the adhesive layer 88b, and the light emitting element 142b is a green light source that emits green light 132b toward the adhesive layer 88a or the adhesive layer 88b. The light emitting element 142c is a blue light source that emits blue light 132c toward the adhesive layer 88a or the adhesive layer 88b.

  Then, the reset light source 78 drives the three types of light emitting elements 142a to 142c at the same time to perform light reset on the photodetecting element 94, so that three colors of light (red light 132a, green light 132b, and blue light) are driven. By simultaneously emitting the light 132c), it is output as reset light 132 (white light for light reset (one light), light of the first wavelength) that combines these three colors of light (see FIG. 8A). Therefore, the white light obtained by synthesizing the red light 132a, the green light 132b, and the blue light 132c is used as the reset light 132 through the scintillator 74, the adhesive layer 88a or the adhesive layer 88b, and the planarizing film 96, thereby detecting the light. By being incident on the light 94, the light detection element 94 is optically reset.

  On the other hand, when the reset light source 78 functions as a detection light source for detecting the deterioration (yellowing) of the adhesive layer 88a or the adhesive layer 88b, the reset light source 78 drives at least the light emitting element 142c to cause blue light 132c ( The other light used for purposes other than the optical reset, the second wavelength light) is emitted, and the blue light 132c is irradiated to the adhesive layer 88a or the adhesive layer 88b through the scintillator 74 as the deterioration detection light. . In this case, if the adhesive layer 88a or the adhesive layer 88b deteriorates and yellowing occurs (see FIGS. 9A and 9B), the blue light 132c is absorbed by the yellowed adhesive layer 88a or the adhesive layer 88b. In this case, the light does not reach the light detection element 94 or is incident on the light detection element 94 in a state where the amount of light is reduced.

  The light detection element 94 detects the blue light 132c that has passed through the adhesive layer 88a or the adhesive layer 88b, and outputs an electrical signal (light detection signal) corresponding to the amount of the blue light 132c. Accordingly, the level of the light detection signal when the adhesive layer 88a or the adhesive layer 88b is not deteriorated (the level of the light detection signal when the electronic cassette 20A starts to be used and the light detection amount A0), and the adhesive layer 88a. Alternatively, by comparing the level of the light detection signal when the blue light 132c is actually irradiated to the adhesive layer 88b (for example, the light detection amount A1 as the current light detection signal level), the adhesive layer 88a or It is possible to grasp (detect) whether or not the deterioration of the adhesive layer 88b has occurred.

  Such a deterioration detection operation is desirably performed, for example, in a form that is added to the periodic maintenance of the electronic cassette 20 or the calibration of the electronic cassette 20 before daily imaging.

  In the above description, a case has been described in which deterioration detection is performed on the adhesive layer 88a or the adhesive layer 88b by irradiating the adhesive layer 88a or the adhesive layer 88b with only the blue light 132c as deterioration detection light.

  In the electronic cassette 20 according to the present embodiment, the deterioration detection light used for the deterioration detection operation has a peak wavelength different from the peak wavelength of the reset light 132 (white light wavelength) output from the reset light source 78 at the time of light reset. The light in the wavelength range including the peak wavelength that includes the peak wavelength that can be absorbed by the adhesive layer 88a or the adhesive layer 88b may be used.

  Therefore, in the deterioration detection operation, it is possible to detect the deterioration of the adhesive layer 88a or the adhesive layer 88b by adopting any of the following operations (1) to (4) including the above-described operation. It is.

  (1) When the adhesive layer 88a or the adhesive layer 88b is irradiated with the blue light 132c as deterioration detection light.

  (2) When irradiating the adhesive layer 88a or the adhesive layer 88b with the green light 132b as deterioration detection light.

  (3) When irradiating the adhesive layer 88a or the adhesive layer 88b simultaneously with the green light 132b and the blue light 132c as deterioration detection light.

  (4) When red light 132a, green light 132b, and blue light 132c are sequentially irradiated at different times.

  When the red light 132a, the green light 132b, and the blue light 132c are sequentially irradiated at different times, if the adhesive layer 88a or the adhesive layer 88b has deteriorated (yellowed), for example, the red light 132a The green light 132b is not absorbed by the layer 88a or the adhesive layer 88b but is incident on the light detecting element 94 as it is, and the green light 132b is partially absorbed by the adhesive layer 88a or the adhesive layer 88b and incident on the light detecting element 94. The light 132c is absorbed by the adhesive layer 88a or the adhesive layer 88b and does not reach the light detection element 94 (see FIG. 9B).

  As a result, in (4), in the light detection element 94, for the red light 132a, the detection amount of the light detection signal does not change regardless of whether the adhesive layer 88a or the adhesive layer 88b is deteriorated (the detection amount A0 is maintained). For the green light 132b, the detection amount of the light detection signal decreases due to the deterioration of the adhesive layer 88a or the adhesive layer 88b (the detection amount changes from A0 to A1), and for the blue light 132c, the adhesive layer 88a or Due to the deterioration of the adhesive layer 88b, the detection amount of the light detection signal becomes substantially zero level. Therefore, in the case of (4), it is possible to determine the presence or absence of deterioration of the adhesive layer 88a or the adhesive layer 88b by comparing the detected amounts at different time points.

  Further, the reset light source 78 may have the configuration of FIGS. 11A to 12B instead of the array of the light emitting elements 142a to 142c of FIGS. 8A to 9B.

  The reset light source 78 in FIGS. 11A and 11B is an edge-light type backlight arranged so as to face the light detection substrate 72 through the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b.

  In this case, in the reset light source 78 of the backlight, the light guide plate 150 is disposed between the bottom plate 80 of the housing 44 and the scintillator 74, and three types of light emitting elements 162a to 162a are disposed on the side of the light guide plate 150. A substrate 160 in which 162c is arranged in a line (in an array) is arranged. In this case, the arrangement locations of the light emitting elements 162 a to 162 c and the substrate 160 are non-irradiated areas of the radiation 16. Further, a diffusion sheet 154 is interposed between the light guide plate 150 and the scintillator 74, and a reflection sheet 156 is disposed so as to surround the light guide plate 150, the three types of light emitting elements 162a to 162c, and the substrate 160. .

  Here, when the red light 132a, the green light 132b, and the blue light 132c are respectively incident on the light guide plate 150 from the three types of light emitting elements 162a to 162c, the red light 132a, the green light 132b, and the blue light 132c that are incident on the light guide plate 150 are After the surface reflection is repeated between the reflection sheet 156 and the diffusion sheet 154 in the light guide plate 150 and spreads over the entire light guide plate 150, the surface emission reset light 132 (white light) is transmitted from the diffusion sheet 154 to the scintillator 74. Emitted. As a result, the reset light source 78 can perform optical reset by uniformly irradiating the light detection elements 94 with the reset light 132 via the scintillator 74, the adhesive layer 88 a or the adhesive layer 88 b, and the planarizing film 96. it can. In FIG. 11A, only one reset light 132 is shown.

  On the other hand, in the case where the backlight reset light source 78 functions as a deterioration detection light source, the light guide plate 150 can be obtained by causing the light emitting elements 162a to 162c to emit light by any one of the methods (1) to (4) described above. The surface emission degradation detection light (light in a wavelength region including a peak wavelength different from the peak wavelength of the white light) can be output to the scintillator 74 through the diffusion sheet 154.

  The reset light source 78 of FIG. 12A is also an edge light type backlight, but in place of the light emitting elements 162a to 162c and the substrate 160, three types of cold cathode tubes 152a to 152c are arranged, and therefore the reset light source 78 of FIG. Different from the configuration. Accordingly, even in this case, the locations where the cold cathode fluorescent lamps 152a to 152c are arranged are the non-irradiated areas of the radiation 16.

  Also in this case, when the red light 132a, the green light 132b, and the blue light 132c are incident on the light guide plate 150 from the three types of cold cathode fluorescent lamps 152a to 152c, the red light 132a, the green light 132b, and the blue light incident on the light guide plate 150, respectively. 132c repeats surface reflection between the reflection sheet 156 and the diffusion sheet 154 in the light guide plate 150 and spreads over the entire light guide plate 150, and then the surface emitting reset light 132 (white light) is transmitted from the diffusion sheet 154 to the scintillator 74. ). When the reset light source 78 functions as a deterioration detection light source, the light guide plate is driven by driving the cold-cathode tubes 152a to 152c based on any one of the methods (1) to (4) described above. 150 can output surface emission deterioration detection light (light in a wavelength region including a peak wavelength different from the peak wavelength of the white light) to the scintillator 74 through the diffusion sheet 154. In FIG. 11B, only one green light 132b is shown.

  The reset light source 78 of FIG. 12B is configured by laminating three electroluminescence light sources 78 a to 78 c in the irradiation direction of the radiation 16. In this case, each of the electroluminescence light sources 78a to 78c is an organic electroluminescence (organic EL) light source or an inorganic electroluminescence (inorganic EL) light source.

  That is, in the reset light source 78, the lowermost electroluminescence light source 78a that emits red light 132a is laminated with the intermediate electroluminescence light source 78b that emits green light 132b through the electrical insulating layer 166, and the electroluminescence light source 78b. Further, an uppermost electroluminescence light source 78c that emits blue light 132c is laminated through an electric insulating layer 168.

  In this case, the electroluminescence light source 78 a includes a light emitting layer 170 a made of an organic EL material or an inorganic EL material, a transparent electrode 172 a made of ITO that can transmit the reset light 132, and a metal electrode that is non-transmissive to the reset light 132. 174a has a sandwiched structure. The electroluminescence light source 78b has a structure in which a light emitting layer 170b made of an organic EL material or an inorganic EL material is sandwiched between two transparent electrodes 172b and 174b made of ITO that can transmit the reset light 132. Further, the electroluminescence light source 78c has a structure in which a light emitting layer 170c made of an organic EL material or an inorganic EL material is sandwiched between two transparent electrodes 172c and 174c made of ITO that can transmit the reset light 132.

  If a voltage (for example, a voltage at which the transparent electrode 172a becomes positive and the metal electrode 174a becomes negative) is applied between the transparent electrode 172a and the metal electrode 174a from a power source (not shown), the light emitting layer 170a is transparent. Surface emitting red light 132a can be output through the electrode 172a. Further, when a voltage (for example, a voltage at which the transparent electrode 172b becomes positive and the transparent electrode 174b becomes negative) is applied between the two transparent electrodes 172b and 174b from the power source, the transparent electrode 172b is changed from the light emitting layer 170b. The surface emitting green light 132b can be output via Furthermore, when a voltage (for example, a voltage at which the transparent electrode 172c becomes positive and the transparent electrode 174c becomes negative) is applied between the two transparent electrodes 172c and 174c from the power source, the transparent electrode 172c is removed from the light emitting layer 170c. Through this, surface-emitting blue light 132c can be output.

  Thus, also in the reset light source 78 configured by laminating the three types of electroluminescence light sources 78 a to 78 c, each light detection element 94 is interposed via the scintillator 74, the adhesive layer 88 a or the adhesive layer 88 b, and the planarizing film 96. The reset light 132 is evenly irradiated to reset the light, or the deterioration detection light is applied to the adhesive layer 88a or the adhesive layer 88b via the scintillator 74 according to any one of the methods (1) to (4). Uniform irradiation is possible.

  13A to 14 illustrate the manufacturing process of the electronic cassette 20A according to the first embodiment.

  First, as shown in FIG. 13A, a scintillator 74 is formed on a vapor deposition substrate 240 with a release layer 242 interposed therebetween. Next, as shown in FIG. 13B, the scintillator 74 is sealed with a moisture-proof protective material 86 so that each column in the columnar crystal structure 84 is covered with polyparaxylylene resin by CVD (chemical vapor deposition). To do. Next, as shown in FIG. 13C, the tip portion of the scintillator 74 and the light detection substrate 72 are adhered by the adhesive layer 88a or adhered by the adhesive layer 88b, using the light detection substrate 72 as a transfer body. Note that adhesion or adhesion (transfer) of the scintillator 74 or the like to the light detection substrate 72 as a transfer body may be performed using a known transfer technique.

  Next, by irradiating the peeling layer 242 with a laser beam (not shown), the deposition substrate 240 and the peeling layer 242 are peeled from the scintillator 74 as shown in FIG. Thereafter, the radiation detector 70 is housed in the housing 44 by incorporating the light detection substrate 72, the scintillator 74, and the reset light source 78 in the housing 44 in the order shown in FIG. 4A.

  When manufacturing the electronic cassette 20B according to the second embodiment, after the step of FIG. 14, the non-columnar crystal portion 82 side of the scintillator 74 is removed, and finally, the housing 44 in the order shown in FIG. 4B. The light detection substrate 72, the scintillator 74, and the reset light source 78 may be incorporated inside. In the case of the second embodiment, the scintillator 74 may be vapor-deposited on the vapor deposition substrate 240 according to the vapor deposition conditions after determining the vapor deposition conditions such that the non-columnar crystal portion 82 is not formed. In this way, the occurrence of light scattering at the non-columnar crystal portion 82 can be avoided.

  Further, when the electronic cassette 20C according to the third embodiment is manufactured, the scintillator 74 is directly formed on the vapor deposition substrate 108 that is transmissive to the reset light 132, and then the housing is arranged in the order shown in FIG. 4C. The light detection substrate 72, the scintillator 74, and the reset light source 78 may be incorporated in the interior 44. The vapor deposition substrate 108 that is transmissive to the reset light 132 is not only a glass substrate but also a light transmissive polyimide film, polyarylate film, biaxially stretched polystyrene film, aramid film, or bio-nanofiber. Any flexible plastic film may be used.

  FIG. 15 is a schematic electrical configuration diagram of the electronic cassette 20 (20A to 20C) shown in FIG.

  The light detection substrate 72 of the electronic cassette 20 (20A to 20C) has a structure in which the light detection elements 94 and the TFTs 92 are arranged in an array form (matrix form) on a base material 90 (see FIGS. 5A to 7). In the following description, the light detection element 94 is also referred to as a pixel 190.

  The pixels 190 arranged in a matrix are driven by being supplied with a bias voltage from a bias power supply 192 of the drive circuit unit 180, and are generated by photoelectrically converting the visible light 130 converted from the radiation 16 in the scintillator 74. Accumulated charge. The charge accumulated in each pixel 190 can be read out as a pixel value (charge signal, electric signal) of an analog signal via each signal line 196 by sequentially turning on the TFT 92 for each column. In FIG. 15, for the sake of convenience, the pixels 190 and the TFTs 92 are arranged in the form of 4 vertical pixels × 4 horizontal pixels, but it is needless to say that a desired number of arrays may be used.

  A gate line 194 extending in the row direction and a signal line 196 extending in the column direction are connected to the TFT 92 connected to each pixel 190. Each gate line 194 is connected to a gate drive unit 198 constituting the drive circuit unit 180, and each signal line 196 is connected to the multiplexer unit 202 constituting the drive circuit unit 180 via the charge amplifier 200. The multiplexer unit 202 is connected to an AD conversion unit 204 that converts an electrical signal of an analog signal into an electrical signal of a digital signal. The AD conversion unit 204 outputs an electrical signal (a pixel value of the digital signal, hereinafter also referred to as a digital value) converted into a digital signal to the cassette control unit 182. The drive circuit unit 180 is disposed in the panel unit 40 or the control unit 42 (see FIG. 2). Further, the cassette control unit 182 is disposed in the control unit 42.

  The cassette control unit 182 controls the entire electronic cassette 20 (20A to 20C). In this case, the computer can function as the cassette control unit 182 by causing an information processing apparatus such as a computer to read a predetermined program.

  A memory 184 and a communication unit (notification unit) 186 are connected to the cassette control unit 182. The memory 184 stores the pixel value of the digital signal, and the communication unit 186 transmits and receives signals to and from the console 22. In this case, the communication unit 186 transmits one image (one frame image) configured by arranging a plurality of pixel values in a matrix to the console 22. The power supply unit 188 supplies power to the cassette control unit 182, the memory 184, the communication unit 186, and the like, and also supplies it to the bias power source 192. Note that the memory 184, the communication unit 186, and the power supply unit 188 are also accommodated in the control unit 42.

  The cassette control unit 182 includes a photographing order determination unit 210, a light reset operation determination unit 214, a light source control unit 218, a coloring detection operation determination unit 220, and a deterioration determination unit 222.

  The imaging order determination unit 210 specifies (determines) an imaging method included in the imaging order when receiving order information (imaging order) related to the irradiation of the radiation 16 (imaging radiographic image) on the subject 14 from the console 22. . Note that the order information (imaging order) is created by a doctor in the RIS 26 or the HIS 28. In addition to subject information for identifying the subject 14 such as the name, age, and sex of the subject 14, the order information (imaging order) is used for photographing. This includes information on the radiation output device 18 and the electronic cassette 20 to be used, an imaging region of the subject 14, a shooting technique, an imaging method (still image shooting, moving image shooting), and the like.

  The light reset operation determination unit 214 determines whether or not to perform a light reset for each light detection element 94 based on the imaging method specified by the imaging order determination unit 210. The light source controller 218 controls the output of the reset light 132 from the reset light source 78 in the light reset operation, or the red light 132a, the green light 132b, and / or the blue light 132c from the reset light source 78 in the deterioration detection operation. Control the output.

  The coloring detection operation determination unit 220 instructs the light source control unit 218 to output deterioration detection light from the reset light source 78 during regular maintenance or before the start of daily photographing.

  The light source control unit 218 controls the reset light source 78 in accordance with an instruction from the coloring detection operation determination unit 220, and deterioration detection light (for example, from the reset light source 78 to the adhesive layer 88a or the adhesive layer 88b via the scintillator 74) When the blue light 132c) is irradiated, the light detection element 94 detects an electric signal (light detection signal) corresponding to the deterioration detection light incident through the adhesive layer 88a or the adhesive layer 88b, and generates a charge. accumulate.

  Therefore, the deterioration determining unit 222 sequentially turns on the TFTs 92 so that the adhesive layer 88a or the adhesive layer 88b is based on the signal level (output level) of the light detection signal read through each signal line 196. It is determined whether or not the radiation 16 has deteriorated.

  It should be noted that the imaging method determination result (determination result) in the imaging order determination unit 210, the determination result in the light reset operation determination unit 214, the status of control of the reset light source 78 by the light source control unit 218, and the color detection operation determination unit 220 The state of the instruction to the light source control unit 218 and the determination result of the deterioration of the adhesive layer 88a or the adhesive layer 88b by the deterioration determination unit 222 are displayed on the screen by the display operation unit 56 and output as sound through the speaker 58. Furthermore, the communication unit 186 transmits (notifies) the console 22 by wireless communication.

  The radiographic imaging system 10 having the electronic cassette 20 (20A to 20C) according to the present embodiment is basically configured as described above. Next, with reference to FIGS. While explaining.

  In the description of FIGS. 16 to 19, the operation of the radiographic imaging system 10 when the electronic cassette 20A according to the first embodiment is used will be described. However, the electronic cassettes 20B and 20C according to the second and third embodiments will be described. Of course, even if it is used, it can be similarly applied.

  Here, first, radiographic imaging of the subject 14 as a basic operation of the radiographic imaging system 10 will be described with reference to FIGS. 16 and 17, and then performed at regular maintenance or before daily imaging. The deterioration detection operation of the adhesive layer 88a or the adhesive layer 88b will be described with reference to FIGS.

  First, in step S1 of FIG. 16, the console 22 (see FIG. 1) acquires the order information (imaging order) created by the doctor in the RIS 26 or the HIS 28. In step S <b> 2, the doctor sets imaging conditions for the subject 14 based on the order information acquired by the console 22. Note that the imaging conditions are various conditions necessary for irradiating the imaging region of the subject 14 with the radiation 16 such as the tube voltage and tube current of the radiation source 30 and the exposure time of the radiation 16.

  In step S3, the doctor grasps the handle 52 (see FIGS. 2 and 3) of the electronic cassette 20 (20A) stored in a predetermined storage location, conveys the electronic cassette 20A, and places it on the imaging table 12. Install. In the next step S <b> 4, the doctor lies the subject 14 on the imaging table 12 and the electronic cassette 20 </ b> A so that the imaging region of the subject 14 is within the imaging region 50, and positions the imaging region with respect to the imaging region 50. I do.

  In this case, the power supply unit 188 (see FIG. 15) constantly supplies power to the cassette control unit 182, the communication unit 186, and the display operation unit 56. Then, after the positioning of the subject 14 is completed, when the doctor operates the display operation unit 56 to instruct the activation of the electronic cassette 20A, the cassette control unit 182 connects the power supply unit 188 to the drive circuit unit 180 and the speaker 58. Start power supply. As a result, the bias power source 192 starts to supply a bias voltage to each pixel 190 (photodetection element 94), so that each pixel 190 is in a state where charge can be accumulated. Further, the speaker 58 reaches a state where the signal from the cassette control unit 182 can be output to the outside as a sound. As a result, the electronic cassette 20A is switched from the sleep state to the activated state.

  Then, the cassette control unit 182 transmits a transmission request signal for requesting transmission of imaging orders and imaging conditions to the console 22 wirelessly via the communication unit 186. When the console 22 receives the transmission request signal, the console 22 wirelessly transmits the imaging order and the imaging conditions to the electronic cassette 20A, and transmits the imaging conditions to the radiation output device 18 by radio. Thereby, in the radiation output device 18, the received imaging condition is registered in the radiation control device 32. In the electronic cassette 20 </ b> A, the received imaging order and imaging conditions are registered in the cassette control unit 182. When the cassette control unit 182 receives the order information and the imaging conditions, the cassette control unit 182 may display the information on the display operation unit 56.

  In step S5, the shooting order determination unit 210 of the cassette control unit 182 determines a shooting method (at least one still image shooting and moving image shooting) included in the shooting order, and the determination result is sent to the light reset operation determination unit 214. In addition to the notification, it is also displayed on the display operation unit 56.

  Based on the determination result notified from the imaging order determination unit 210, the light reset operation determination unit 214 determines whether or not to perform a light reset on each pixel 190 (each light detection element 94). For example, in the case of a determination result indicating still image shooting or moving image shooting at a relatively low frame rate, the light reset operation determination unit 214 determines that the light reset operation for each pixel 190 is unnecessary (step S6: NO), The determination result that the light reset operation is unnecessary is notified to the light source control unit 218 and is also displayed on the display operation unit 56. Furthermore, a sound indicating the determination result may be output from the speaker 58. On the other hand, in the case of a determination result indicating moving image shooting at a relatively high frame rate, the light reset operation determination unit 214 determines that the light reset operation for each pixel 190 is necessary (step S6: YES), and executes the light reset operation. Is notified to the light source control unit 218 and is also displayed on the display operation unit 56, and is further output from the speaker 58 as a sound indicating the determination result.

  If the determination result in step S6 is affirmative, the light source control unit 218 determines that the reset light source 78 (FIGS. 3, 4A, 5A, 8A to 9B, and The output of the reset light 132 is started by driving (see FIGS. 11A to 12B). In this case, the reset light source 78 emits the red light 132a, the green light 132b, and the blue light 132c all at once, and outputs white light obtained by combining these lights as the reset light 132. As a result, the reset light 132 enters the light detection substrate 72 via the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b. As a result, light reset is performed on each pixel 190 (each light detection element 94). Thereafter, the light source control unit 218 terminates the light reset operation by stopping the output of the reset light 132 from the reset light source 78.

  Since the determination results of steps S5 and S6 are displayed on the display operation unit 56, the doctor can visually check the display contents of the display operation unit 56 to perform the imaging method and the light reset operation for each pixel 190. Whether or not it is executed can be grasped. If a sound indicating each determination result in steps S5 and S6 is output from the speaker 58, the doctor can understand the imaging method and the presence or absence of the light reset operation for each pixel 190 by listening to the sound. . Furthermore, each determination result may be transmitted from the communication unit 186 to the console 22 by wireless communication. In this case, since the console 22 can transfer the received determination results to the display device 24 by wireless communication and display the results on the display device 24, the doctor can perform an imaging method or optical reset for each pixel 190. It is possible to reliably grasp the presence or absence of operation.

  In this way, after the light reset operation in step S7 is completed or after the light reset unnecessary determination process in step S6, when the doctor half-presses the radiation switch 34 in step S8 in FIG. 32 prepares for the irradiation of the radiation 16 and transmits a notification signal notifying the preparation for irradiation to the console 22 by radio. The console 22 wirelessly transmits a synchronization control signal for synchronizing with irradiation of the radiation 16 from the radiation source 30 to the electronic cassette 20A. When the cassette control unit 182 of the electronic cassette 20A receives the synchronization control signal, the cassette control unit 182 displays information indicating that the irradiation preparation has been started on the display operation unit 56 and also notifies the outside via the speaker 58 as a sound. Good.

  Thereafter, when the doctor fully presses the radiation switch 34, the radiation control device 32 irradiates the imaging region of the subject 14 with the radiation 16 from the radiation source 30 for a predetermined time set under the imaging conditions (step S9). In this case, the radiation control device 32 may transmit a notification signal for notifying the start of irradiation to the console 22 wirelessly simultaneously with the start of irradiation of the radiation 16. The console 22 transfers the received notification signal to the electronic cassette 20A, and when the cassette control unit 182 of the electronic cassette 20A receives the notification signal, the display operation unit 56 displays information indicating that irradiation is in progress. At the same time, the sound may be notified to the outside through the speaker 58.

  In step S10 in which the radiation 16 passes through the imaging region of the subject 14 and reaches the radiation detector 70 of the electronic cassette 20A, the radiation detector 70 is an ISS radiation detector shown in FIGS. 3 and 4A. Therefore, the radiation 16 reaches the columnar crystal structure 84 of the scintillator 74 through the light detection substrate 72 and the adhesive layer 88a or the adhesive layer 88b.

  The columnar crystal structure 84 emits visible light 130 (see FIG. 8B) having an intensity corresponding to the intensity of the radiation 16, and the visible light 130 passes from the columnar portion of the columnar crystal structure 84 via the adhesive layer 88a or the adhesive layer 88b. Incident on the light detection substrate 72. Each pixel 190 converts visible light 130 incident through the planarization film 96 into an electric signal and accumulates it as an electric charge. Next, charge information that is a radiographic image of the imaging region of the subject 14 held in each pixel 190 is read according to a drive signal supplied from the cassette control unit 182 to the gate drive unit 198.

  That is, the gate driving unit 198 sequentially selects the gate lines 194 from the 0th row, supplies a gate signal to the selected gate line 194, and turns on the TFT 92 to which the gate signal is supplied, so that each pixel is turned on. The charges accumulated in 190 are sequentially read from the 0th row in units of rows. The electric charges sequentially read out in units of rows from the respective pixels 190 are input to the charge amplifiers 200 of the respective columns through the respective signal lines 196, and then the electric signals of the digital signals are transmitted through the multiplexer unit 202 and the AD conversion unit 204. The signal is stored in the memory 184 (step S11). That is, the memory 184 sequentially stores image data for one row obtained in units of rows.

  The radiographic image stored in the memory 184 is transmitted to the console 22 wirelessly through the communication unit 186 together with the cassette ID information for identifying the electronic cassette 20A. The console 22 displays the received radiation image and cassette ID information on the display device 24 (step S12). Further, the cassette control unit 182 may display both the radiation image and the cassette ID information on the display operation unit 56.

  If the doctor confirms that the radiation image has been obtained by visually recognizing the display content of the display device 24 or the display operation unit 56, the doctor completes all the imaging registered in the imaging order (step S13: YES). ), The subject 14 is released from the positioning state (step S14).

  Next, when the doctor operates the display operation unit 56 to instruct to stop the electronic cassette 20 </ b> A, the cassette control unit 182 stops the power supply from the power supply unit 188 to the drive circuit unit 180 and the speaker 58. Thereby, the supply of the bias voltage from the bias power source 192 to each pixel 190 is also stopped. As a result, the electronic cassette 20A shifts from the activated state to the sleep state.

  In step S15, after confirming that the display on the display / operation unit 56 has disappeared and the electronic cassette 20A has shifted to the sleep state, the doctor holds the handle 52 of the electronic cassette 20A and stores the electronic cassette 20A in a predetermined storage state. Transport it to the place.

  In step S13, when all the shootings are not completed (step S13: NO), the determination process in step S6 is performed again before the next shooting. In this case, if the next shooting is a still image shooting, the process of step S8 is performed again after the process of step S6 (and step S7). If the next shooting is shooting at the next frame in the moving image shooting, the process of step S8 is omitted after the process of step S6 (and step S7), and the process of step S9 is performed.

  The basic operation of the radiographic imaging system 10 (radiographic imaging of the subject 14) is as described above.

  Next, the deterioration detection operation of the adhesive layer 88a or the adhesive layer 88b (see FIG. 4A, FIG. 5A to FIG. 9B, FIG. 11A, FIG. This will be described with reference to FIGS. 18 and 19.

  First, before regular imaging or daily imaging, the doctor grasps the handle 52 (see FIGS. 2 and 3) of the electronic cassette 20 (20A) stored in a predetermined storage location and holds the electronic cassette. 20A is transported and installed on the imaging table 12 (see FIG. 1). Next, the doctor operates the display operation unit 56 (see FIGS. 2 and 5) to activate the electronic cassette 20A. Accordingly, the cassette control unit 182 starts power supply from the power supply unit 188 to the drive circuit unit 180 and the speaker 58, and the bias power supply 192 starts supplying bias voltage to each pixel 190, and each pixel 190 Is in a state where charge can be accumulated.

  Further, for example, the doctor operates the display operation unit 56 to instruct the maintenance of the electronic cassette 20A and the execution of calibration before photographing. Thereby, the coloring detection operation determination unit 220 and the deterioration determination unit 222 can grasp that the maintenance or calibration of the electronic cassette 20A is executed.

  Then, in steps S21 to S23 in FIG. 18, the same radiation imaging as in steps S8 to S10 in FIG. As a result, each pixel 190 converts the visible light 130 into an electrical signal and accumulates it as an electric charge (radiation detection amount). Therefore, the charge accumulated in each pixel 190 becomes charge information corresponding to the radiographic image taken without the subject 14.

  Then, the charge information held in each pixel 190 in the absence of the subject 14 is read in accordance with the drive signal supplied from the cassette control unit 182 to the gate drive unit 198 in the same manner as the processing in step S10 described above. The digital signal is stored in the memory 184 as an electrical signal (step S24). In this case, the memory 184 stores a pixel value (radiation detection amount) A2 of a digital signal corresponding to the charge information as a signal level (output level) of each pixel 190.

  Thereafter, in the electronic cassette 20A, an optical reset operation similar to step S7 may be performed as necessary (step S25).

  In the next step S <b> 26, the coloring detection operation determination unit 220 stores the pixel value A <b> 2 for each pixel 190 in the memory 184 and confirms that the light reset operation has been performed as necessary, and then the light source control unit 218. Is instructed to output deterioration detection light from the reset light source 78. The light source controller 218 irradiates the adhesive layer 88a or the adhesive layer 88b with deterioration detection light (for example, blue light 132c) from the reset light source 78 via the scintillator 74 in accordance with an instruction from the coloring detection operation determination unit 220.

  The deterioration detection light that has passed through the adhesive layer 88a or the adhesive layer 88b enters a light detection element 94, and the light detection element 94 converts the incident deterioration detection light into an electrical signal (light detection signal), Accumulated as charges (photodetection amount) (step S27).

  In the next step S28, the gate drive unit 198, similar to steps S10 and S23, in accordance with the drive signal supplied from the cassette control unit 182, the charge corresponding to the deterioration detection light held in each pixel 190. Information is read out and stored in the memory 184 as an electrical signal of a digital signal. In this case, the memory 184 stores a pixel value (photodetection amount) A3 of a digital signal corresponding to the charge information as the signal level (output level) of each pixel 190.

  As a result, in the memory 184, the radiography and the deterioration detection operation without the subject 14 are performed at the time of maintenance or calibration, so that a pixel as a radiation detection amount at the time of maintenance or calibration is obtained. The value A2 and the pixel value A3 as the light detection amount are stored for each pixel 190 (light detection element 94). The memory 184 also stores a pixel value (initial value) A20 of the radiation detection amount and a pixel value (initial value) A30 of the light detection amount for each pixel 190 at the start of use of the electronic cassette 20A.

  Therefore, in the next step S29, the deterioration determination unit 222 reads all the pixel values A2 and initial values A20 for each pixel 190 from the memory 184, and the ratio R (R = A2 / R) between the pixel values A2 and the initial values A20. A20) is calculated for each photodetecting element 94.

  Here, the ratio R is the ratio of the decrease in the pixel value A2 of the radiation detection amount at the present time to the initial value A20 of the radiation detection amount in the electronic cassette 20A at the start of use (initial state), that is, in each pixel 190. The decreasing rate of the detection capability of the visible light 130 converted from the radiation 16 is shown. For example, if the current pixel value A2 is 0.9 × A20 with respect to the initial value A20, then R = A2 / A20 = 0.9 (90%), and the detection capability is reduced by 10%. It shows that.

  In the next step S30, the deterioration determination unit 222 determines, for each pixel 190, whether or not the ratio R obtained as described above is lower than a predetermined threshold value Rth.

  When the total number of pixels 190 with R <Rth exceeds a predetermined number (step S30: YES), the deterioration determination unit 222 determines that some failure has occurred inside the electronic cassette 20A, and then The pixel value A3 and the initial value A30 of each pixel 190 are read from the memory 184. Then, for each pixel 190, the deterioration determination unit 222 multiplies the initial value A30 by the ratio R, and a pixel value threshold A3th (A3th = R ×) corresponding to the light detection amount that can be detected by each pixel 190 at the present time. A30) is calculated (step S31).

  This threshold value A3th is a threshold value for determining whether or not the adhesive layer 88a or the adhesive layer 88b is deteriorated. If the pixel value A3 actually obtained by the deterioration detection operation is lower than the threshold value A3th, the adhesive layer It is determined that the deterioration of the 88a or the adhesive layer 88b has occurred. As described above, if the detection capability of each pixel 190 is reduced, it is assumed that the pixel value A3 for each pixel 190 is also affected by the reduction of the detection capability. Therefore, in the present embodiment, the deterioration of the adhesive layer 88a or the adhesive layer 88b is not performed using the threshold value A3th considering the ratio R indicating the reduction rate of the detection capability, instead of the initial value A30 at the start of use of the electronic cassette 20A. Determine presence or absence.

  That is, in step S <b> 32, the deterioration determination unit 222 compares the pixel value A <b> 3 with the threshold value A <b> 3 th for each photodetecting element 94 and determines whether A <b> 3 << A <b> 3 th (or A <b> 3 <A <b> 3 th).

  When the total number of pixels 190 that satisfy A3 << A3th (or A3 <A3th) exceeds a predetermined number (step S32: YES), the deterioration determination unit 222 determines that the adhesive layer 88a or the adhesive layer 88b has deteriorated. It determines with having generate | occur | produced (step S33), the screen is displayed on the display operation part 56, and it outputs as a sound via the speaker 58 (step S34). Further, the deterioration determination unit 222 transmits (notifies) the wireless communication from the communication unit 186 to the console 22, and the console 22 transfers the received determination result to the display device 24 by wireless communication to the display device 24. It is displayed (step S34).

  Accordingly, the doctor grasps that the deterioration of the adhesive layer 88a or the adhesive layer 88b has occurred by visually recognizing the display content of the display operation unit 56 or the display device 24 or by listening to the sound from the speaker 58. In addition, it is possible to take necessary measures such as requesting repair or replacement of the electronic cassette 20A. Further, if the determination result is transmitted from the electronic cassette 20A to the console 22, or if the determination result is transferred from the console 22 to the RIS 26 or the HIS 28, a specific failure content is provided to the manufacturer of the electronic cassette 20A. Requests for repair or replacement of the electronic cassette 20A including (deterioration of the adhesive layer 88a or the adhesive layer 88b) can also be made promptly.

  On the other hand, when step S32 is not a positive determination result, that is, when the result of A3 ≧ A3th is obtained in a large number of pixels 190 (photodetection elements 94), the deterioration determination unit 222 determines whether the adhesive layer 88a or the adhesive layer 88b is not deteriorated but it is determined that the scintillator 74 is deteriorated (step S35), and the determination result is displayed on the screen by the display operation unit 56 and output as sound through the speaker 58. Furthermore, the communication unit 186 transmits (notifies) the console 22 by wireless communication (step S34). Even in this case, the deterioration determination unit 222 transmits (notifies) the communication unit 186 to the console 22 by wireless communication, and the console 22 transfers the received determination result to the display device 24 by wireless communication, It is displayed on the display device 24 (step S34).

  Thereby, the doctor grasps that the deterioration of the scintillator 74 has occurred by visually recognizing the display contents of the display operation unit 56 or the display device 24, or by listening to the sound from the speaker 58, and the electronic cassette 20A. Necessary measures can be taken, such as requesting repair or replacement. Further, if the determination result is transmitted from the electronic cassette 20A to the console 22, or if the determination result is transferred from the console 22 to the RIS 26 or the HIS 28, a specific failure content is provided to the manufacturer of the electronic cassette 20A. Requests for repair or replacement of the electronic cassette 20A including (deterioration of the scintillator 74) can also be made promptly.

  Further, when step S30 is not a positive determination result, that is, when R ≧ Rth is obtained in a large number of pixels 190 (light detection elements 94), the deterioration determination unit 222 determines that the electronic cassette 20A is normal. It is determined that it is functioning (step S36), and the determination result is displayed on the screen by the display / operation unit 56, output as sound through the speaker 58, and further transmitted from the communication unit 186 to the console 22 by wireless communication. (Notify) (step S34). The console 22 transfers the received determination result to the display device 24 by wireless communication, and displays it on the display device 24 (step S34).

  In this case, the doctor grasps that the electronic cassette 20A functions normally by visually recognizing the display contents of the display operation unit 56 or the console 22 or by listening to the sound from the speaker 58, and the electronic cassette 20 20A can be used for radiography of the subject 14. Further, if the determination result is transmitted from the electronic cassette 20A to the console 22, or if the determination result is transferred from the console 22 to the RIS 26 or the HIS 28, not only the doctor but also other doctors and radiologists in the hospital. In addition, it can be notified that the electronic cassette 20A is an electronic cassette that can be used.

  The operation of the radiographic imaging system 10 having the electronic cassette 20 according to the present embodiment is as described above.

  Next, a modification of the electronic cassette 20 will be described with reference to FIG.

  In FIG. 20, a half mirror 250 is inserted between the scintillator 74 and the reset light source 78.

  That is, the half mirror 250 transmits light from the reset light source 78 (reset light 132 or red light 132a, green light 132b and / or blue light 132c as deterioration detection light) in the direction of the scintillator 74, while The visible light 130 converted from the radiation 16 by the scintillator 74 and traveling in the direction of the reset light source 78 is reflected in the direction of the light detection substrate 72. In this way, by inserting the half mirror 250 between the reset light source 78 and the scintillator 74 and exhibiting the functions of partial reflection and partial transmission with respect to the light, the visible light 130 is reliably incident on the reset light source 78. Therefore, the amount of visible light 130 incident on the light detection element 94 can be increased. On the other hand, by reliably transmitting the light from the reset light source 78 in the direction of the scintillator 74, a light reset operation and a deterioration detection operation for the light detection element 94 can be performed efficiently.

  As described above, according to the electronic cassette 20 (20A to 20C) according to the present embodiment, the electronic cassette 20 can be used by using the light output from the reset light source 78 for purposes other than the optical reset for the light detection substrate 72. 20 It becomes possible to detect deterioration inside. That is, one light (for example, white light obtained by combining red light 132a, green light 132b, and blue light 132c) among at least two lights having different peak wavelengths is irradiated to the light detection substrate 72 as reset light, and the other If the light detection substrate 72 is irradiated with the light (for example, blue light 132c) as deterioration detection light for detecting deterioration inside the electronic cassette 20, the deterioration (failure) inside the electronic cassette 20 is surely performed. Can do.

  Specifically, if the adhesive layer 88a or the adhesive layer 88b is deteriorated due to the irradiation of the radiation 16, the deteriorated adhesive layer 88a or the adhesive layer 88b is light in a wavelength region including a specific peak wavelength (for example, If the light detection substrate 72 is irradiated with light through the deteriorated adhesive layer 88a or adhesive layer 88b to absorb the light in the blue wavelength region), the light absorption in the adhesive layer 88a or adhesive layer 88b The amount of the light incident on the light detection substrate 72 should decrease.

  Therefore, in the present embodiment, the reset light (white light) or the degradation detection light (blue light 132c) is selectively irradiated from the reset light source 78 to the light detection substrate 72 through the adhesive layer 88a or the adhesive layer 88b. Thereby, if the signal level of the deterioration detection light detected by the light detection substrate 72 is lower than the signal level before the deterioration, the adhesive layer 88a or the adhesive layer 88b is deteriorated due to the irradiation of the radiation 16. It can be detected immediately. Further, the reset light source 78 has a function of outputting the reset light 132 and a function of an inspection light source for outputting deterioration detection light (red light 132a, green light 132b and / or blue light 132c). Thus, there is no need to separately prepare the reset light source 78 and the inspection light source.

  In addition, when the reset light source 78 irradiates the light detection element 94 with deterioration detection light via the adhesive layer 88a or the adhesive layer 88b, the deterioration detection light is detected as a light detection signal. The signal level (pixel value A3) of the light detection signal actually detected by the light detection element 94 and the signal level of the light detection signal in a state where the adhesive layer 88a or the adhesive layer 88b is not deteriorated by the radiation 16 ( Since the presence / absence of deterioration of the adhesive layer 88a or the adhesive layer 88b is determined based on the initial value A30), the presence / absence of the deterioration of the adhesive layer 88a or the adhesive layer 88b can be reliably and efficiently detected.

  More specifically, the degradation determination unit 222 includes the signal level (pixel value A2) of the radiation detection signal actually detected by the light detection element 94 and the signal level (pixel value A3) of the light detection signal, and the radiation 16 Based on the signal level (initial value A20) of the radiation detection signal and the signal level (initial value A30) of the light detection signal in a state where the adhesive layer 88a or the adhesive layer 88b is not deteriorated by the adhesive layer 88a or By determining whether or not the adhesive layer 88b and the scintillator 74 have deteriorated, whether the decrease in the level of the electric signal detected by the light detection element 94 is caused by the deterioration of the adhesive layer 88a or the adhesive layer 88b, or the scintillator 74 It is possible to reliably determine whether it is caused by deterioration of

  In the above description, the case where the deterioration of the adhesive layer 88a or the adhesive layer 88b is detected has been described. However, in the present embodiment, the deterioration of the moisture-proof protective material 86 that seals the scintillator 74 can also be detected. . In this case, the deterioration detection light irradiated from the reset light source 78 to the light detection substrate 72 through the moisture-proof protective material 86 and the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b is the moisture-proof protective material 86 deteriorated by the radiation 16. May be light in a wavelength region including a peak wavelength different from that of reset light (white light).

  If the moisture-proof protective material 86 is deteriorated due to the irradiation of the radiation 16, the deteriorated moisture-proof protective material 86 may also absorb the deterioration detection light, so that the deteriorated moisture-proof protective material 86 and the scintillator 74 are interposed. If the light detection substrate 72 is irradiated with the deterioration detection light, the light amount of the deterioration detection light incident on the light detection substrate 72 should be reduced by the absorption of the deterioration detection light by the moisture-proof protective material 86.

  Accordingly, even in this case, the reset light or the degradation detection light is selectively irradiated from the reset light source 78 to the light detection substrate 72 through the moisture-proof protective material 86 and the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b. If the signal level of the degradation detection light detected by the photodetector 94 of the detection substrate 72 is lower than the signal level before degradation, the moisture-proof protective material 86 is degraded due to the irradiation of the radiation 16. It can be detected immediately. Also in this case, since the reset light source 78 also has the function of the inspection light source, it is not necessary to prepare the inspection light source individually.

  In this way, by allowing the reset light source 78 to selectively irradiate the light detection substrate 72 with the reset light or the degradation detection light through the moisture-proof protective material 86 and the scintillator 74 and the adhesive layer 88a or the adhesive layer 88b. In addition, the presence or absence of deterioration inside the electronic cassette 20 due to the radiation 16 (deterioration of the adhesive layer 88a, the adhesive layer 88b, or the moisture-proof protective material 86) is reliably and efficiently detected, and the level of the electric signal detected by the light detection element 94 is The components (adhesive layer 88a, adhesive layer 88b, moisture-proof protective material 86, or scintillator 74) that cause the decrease can be reliably identified.

  The determination result in the deterioration determination unit 222 is displayed on the display operation unit 56, output as a sound from the speaker 58, and further transmitted wirelessly from the communication unit 186 via the console 22 to the display device 24. Therefore, the doctor accurately grasps whether the adhesive layer 88a, the adhesive layer 88b, or the moisture-proof protective material 86 is deteriorated, or whether the scintillator 74 is deteriorated, and takes appropriate measures. (For example, a request for repair or replacement of the electronic cassette 20) can be promptly performed.

  The reset light source 78 is an array of light emitting elements 142 a to 142 c, a backlight, or electroluminescence light sources 78 a to 78 c arranged so as to face the light detection substrate 72 through the scintillator 74.

  In this case, in the backlight type reset light source 78, the cold cathode tube 152 and the light emitting elements 162 a to 162 c can be arranged in the non-irradiation region of the radiation 16. Deterioration of ~ 162c can be avoided. Further, if the reset light source 78 is an organic electroluminescence light source, the reset light source 78 can be thinned.

  In addition, if the light detection element 94 constituting the light detection substrate 72 is made of an organic photoelectric conversion material or an amorphous oxide semiconductor, while the TFT 92 is made of an organic semiconductor material, an amorphous oxide semiconductor or a carbon nanotube, light detection is possible. The element 94 and the TFT 92 can be formed by low temperature film formation.

  Furthermore, by inserting the obliquely incident light cut layer 102 between the light detection substrate 72 and the scintillator 74, both the improvement of the sensitivity of the light detection substrate 72 with respect to the visible light 130 and the suppression of the image blur of the radiation image are achieved. Can be realized.

  In the above description, as an example, the case where the reset light is white light reset light and the deterioration detection light is blue light 132c or the like has been described. However, in the present embodiment, infrared light is more preferable. May use infrared light in a wavelength region including a peak wavelength near 950 nm as reset light. Thereby, compared with the light of a short wavelength, the optical deterioration of a-Si resulting from optical reset can be avoided.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Radiographic imaging system 14 ... Subject 16 ... Radiation 20, 20A-20C ... Electronic cassette 70 ... Radiation detector 72 ... Photodetection board 74 ... Scintillator 78 ... Reset light source 88a ... Adhesive layer 88b ... Adhesive layer 92 ... TFT
94 ... Photodetection element 102 ... Oblique light cut layer 108, 240 ... Deposition substrate 130 ... Visible light 132 ... Reset light 132a ... Red light 132b ... Green light 132c ... Blue light 142a-142c, 162a-162c ... Light emitting element 150 ... Light guide plates 152, 152a to 152c ... Cold cathode tube 154 ... Diffusion sheet 156 ... Reflection sheet 180 ... Drive circuit unit 182 ... Cassette control unit 190 ... Pixel 210 ... Shooting order determination unit 214 ... Light reset operation determination unit 218 ... Light source control unit 220 ... Coloring detection operation determination unit 222 ... Degradation determination unit 242 ... Release layer

Claims (18)

A radiographic imaging apparatus comprising a scintillator that converts radiation into visible light, and a light detection substrate that converts the visible light into an electrical signal,
A light source capable of selectively irradiating the light detection substrate with at least two lights having different peak wavelengths;
The light source irradiates the light detection substrate with one of the at least two lights as reset light, and the other light as deterioration detection light for detecting deterioration in the radiographic apparatus. A radiographic imaging apparatus capable of irradiating a light detection substrate. The apparatus of claim 1.
An adhesive layer that adheres the photodetection substrate and the scintillator, or an adhesive layer that adheres the photodetection substrate and the scintillator;
The light source is capable of irradiating the light detection substrate with the reset light or the deterioration detection light through the adhesive layer or the adhesive layer.
The radiographic imaging apparatus according to claim 1, wherein the deterioration detection light is light having a wavelength range different from a wavelength range of the reset light that can be absorbed by the adhesive layer or the adhesive layer deteriorated by the radiation. The apparatus according to claim 1 or 2,
It further has a moisture-proof protective material for sealing the scintillator,
The light source is capable of irradiating the light detection substrate with the reset light or the deterioration detection light through the moisture-proof protective material and the scintillator.
The radiation image capturing apparatus according to claim 1, wherein the deterioration detection light is light having a wavelength range different from a wavelength range of the reset light, which can be absorbed by the moisture-proof protective material deteriorated by the radiation. The device according to any one of claims 1 to 3,
The light detection substrate includes at least one light detection element that converts the visible light into the electrical signal,
The light detection element detects the deterioration detection light as a light detection signal when the light source irradiates the light detection element with the deterioration detection light,
The radiographic image capturing apparatus is configured such that a signal level of the light detection signal actually detected by the light detection element and a signal level of the light detection signal in a state where no deterioration occurs in the radiographic image capturing apparatus. A radiation image capturing apparatus, further comprising: a deterioration determination unit that determines presence or absence of deterioration in the radiation image capturing apparatus. The apparatus of claim 4.
The light detection element outputs the electrical signal converted from the visible light to the deterioration determination unit as a radiation detection signal,
The deterioration determination unit includes a signal level of the radiation detection signal actually detected by the light detection element and a signal level of the light detection signal, and radiation in a state where no deterioration occurs in the radiation imaging apparatus. A radiographic imaging apparatus, wherein the presence or absence of deterioration in the radiographic imaging apparatus is determined based on a signal level of a detection signal and a signal level of a light detection signal. The device according to claim 4 or 5,
A radiographic imaging apparatus, further comprising: a notification unit that notifies a determination result of the deterioration determination unit to the outside. In the apparatus of any one of Claims 1-6,
The radiographic imaging apparatus, wherein the photodetection substrate, the scintillator, and the light source are sequentially arranged along the radiation direction. The apparatus of claim 7.
The radiographic apparatus according to claim 1, wherein the light source is an array of light emitting elements, a backlight, or an electroluminescence light source disposed so as to face the light detection substrate via the scintillator. The apparatus of claim 8.
The array of light emitting elements outputs a first light emitting element that outputs light in a wavelength region including a first peak wavelength, and light in a wavelength region that includes a second peak wavelength different from the first peak wavelength. And a second light emitting element. The apparatus of claim 8.
The backlight includes a light guide plate arranged on the opposite side of the light detection substrate in the scintillator, at least two light sources arranged on side portions of the light guide plate and capable of outputting light having different peak wavelengths, and A reflection sheet arranged to surround the light guide plate and the at least two light sources, and a diffusion sheet arranged on the surface of the light guide plate on the scintillator side,
The at least two light sources make light incident on the light guide plate,
The light incident on the light guide plate is repeatedly reflected on the surface between the reflection sheet and the diffusion sheet in the light guide plate, and then emitted from the diffusion sheet to the scintillator. apparatus. The apparatus of claim 10.
The at least two light sources are light emitting diodes or cold cathode fluorescent lamps. The apparatus of claim 8.
The electroluminescence light source is composed of at least two light sources that are stacked along the radiation direction of the radiation and that can output light having different peak wavelengths. The apparatus of claim 12.
A radiographic imaging apparatus, wherein the electroluminescence light source is an organic electroluminescence light source. The apparatus according to any one of claims 7 to 13,
After forming the scintillator on a vapor deposition substrate, the scintillator tip portion and the light detection substrate are bonded via an adhesive layer, or are adhered via an adhesive layer. . The apparatus of claim 14.
When the vapor deposition substrate is impermeable to light from the light source, after forming the scintillator on the vapor deposition substrate via a peeling layer, the tip portion of the scintillator and the light detection substrate are bonded to the adhesive layer. Or the adhesive layer is adhered, and then the release layer and the vapor deposition substrate are peeled from the scintillator, and the light source is disposed on the release surface of the scintillator. A radiographic imaging device. The apparatus of claim 14.
The radiographic image capturing apparatus, wherein the light source can be disposed through the vapor deposition substrate when the vapor deposition substrate can transmit light from the light source. The device according to any one of claims 7 to 16,
Between the light detection substrate and the scintillator, an oblique light cut layer that cuts the visible light or the light from the light source traveling in an oblique direction with respect to the radiation irradiation direction is interposed. A radiographic imaging device characterized by the above. The device according to any one of claims 7 to 17,
A radiographic imaging apparatus, wherein a half mirror is interposed between the scintillator and the light source.

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