JP2012073230A - Radiation imaging device and radiation imaging system - Google Patents

Abstract

A radiation imaging apparatus and a radiation imaging system capable of detecting radiation applied to a specific area without providing defective pixels.
A scintillator that emits light from a region irradiated with radiation is disposed so as to overlap an imaging region of a TFT substrate in which a pixel including a sensor section that detects light in the imaging region is two-dimensionally provided. Then, the light guide member 170 is disposed in the detection target region 172 in the scintillator 71 where radiation is detected, and the light generated in the detection target region is detected by the light guide member 170.
[Selection] Figure 8

Description

  The present invention relates to a radiation imaging apparatus and a radiation imaging system, and more particularly to a radiation imaging apparatus and a radiation imaging system that capture a radiation image indicated by radiation emitted from a radiation source and transmitted through a subject.

  In recent years, radiation detectors such as FPD (Flat Panel Detector) that can arrange radiation sensitive layers on TFT (Thin Film Transistor) active matrix substrates and convert radiation such as X-rays directly into digital data have been put into practical use. A radiation imaging apparatus that takes a radiation image represented by irradiated radiation using this radiation detector has been put into practical use. The radiography apparatus using this radiation detector can see images immediately, compared with conventional radiography apparatuses using X-ray film or imaging plate, and radiographic imaging (moving image) (Photographing) can also be performed.

  Various types of radiation detectors of this type have been proposed. For example, radiation is once converted into light by a scintillator such as CsI: Tl or GOS (Gd2O2S: Tb), and the converted light is a photodiode or the like. There is an indirect conversion method in which the sensor unit converts the charges into charges and stores them. In the radiation imaging apparatus, the electric charge accumulated in the radiation detector is read as an electric signal, and the read electric signal is amplified by an amplifier and then converted into digital data by an A / D (analog / digital) converter.

By the way, in the radiation imaging apparatus, a technique is known in which the start and end of radiation irradiation, the amount of radiation irradiation is detected, and the radiation source for irradiating the radiation is controlled.
For example, Patent Document 1 includes an irradiation detection element that detects radiation next to a radiation detector (described as a solid-state imaging device), detects the start and end of radiation emission by the irradiation detection element, and then moves to the radiation detector. A technique for controlling the accumulation of electric charges and the reading of the accumulated electric charges is disclosed.

  By the way, in radiographic image capturing, in order to reduce the exposure dose of the subject or the X-ray technician, the radiation irradiation region is usually narrowed down and the radiation that is necessary for the examination is irradiated.

  For this reason, in a radiation imaging apparatus in which an irradiation detection element is provided beside the radiation detector as in Patent Document 1, when the radiation irradiation area is narrowed, X-rays cannot be sufficiently detected by the irradiation detection element. , X-ray irradiation may not be detected and image acquisition may not be possible.

  Therefore, Patent Document 2 proposes a radiation imaging apparatus in which some of a plurality of pixels provided in a radiation detector are used as pixels for detecting an irradiation amount.

  Further, Patent Document 3 discloses a radiography including a scintillator that converts incident radiation into light, and a photoelectric conversion element substrate in which a plurality of photoelectric conversion elements that convert light into electrical signals are arranged in a two-dimensional array. In the apparatus, a light guide plate is disposed on the surface opposite to the scintillator side of the photoelectric conversion element substrate, and a photodetector for detecting light through the light guide plate and a light source for irradiating light through the light guide plate are provided. A radiation imaging apparatus has been proposed. In the radiation imaging apparatus of Patent Document 3, the amount of radiation is detected by detecting the light of the scintillator with a photodetector through a light guide plate. In addition, dark current is generated in the photoelectric conversion element due to past radiation irradiation history, bias application history, residual charge due to transfer residue remaining in the photoelectric conversion element, trap charge trapped in internal defects, and the like. In some cases, the device characteristics are changed, which adversely affects the image characteristics. As a countermeasure, the radiation imaging apparatus of Patent Document 3 performs optical calibration that improves the characteristics of the photoelectric conversion element by irradiating each photoelectric conversion element of the photoelectric conversion element substrate with light from the light source via the light guide plate. Is going.

JP 2002-181942 A Japanese Patent Laid-Open No. 11-155847 JP 2007-147370 A

  The radiation imaging apparatus of Patent Document 2 can detect radiation even when the radiation irradiation range is narrowed down. However, in the captured image, the pixel portion for detecting the irradiation amount becomes a defective pixel, and image correction is required. .

  In addition, the radiation imaging apparatus of Patent Document 3 needs to be arranged so that the light guide plate covers the entire surface in order to perform optical calibration of the photoelectric conversion element. In the photodetector, the light guide plate is integrated from the entire surface by the light guide plate. It can only detect the amount of light.

  The present invention has been made in view of the above-described facts, and an object thereof is to provide a radiation imaging apparatus and a radiation imaging system that can detect radiation applied to a specific region without providing defective pixels. And

  In order to achieve the above object, the radiation imaging apparatus according to claim 1 is configured so that an imaging panel in which pixels including a sensor unit for detecting light are provided in an imaging area is provided in a two-dimensional manner and the imaging area. A light-emitting layer that is disposed and emits light from a region irradiated with radiation, and a light guide that is partially disposed in a detection target region that detects radiation in the light-emitting layer and guides light generated in the detection target region A member, and a light detection unit that detects light guided by the light guide member.

  According to the first aspect of the present invention, the imaging panel is provided with pixels including a sensor unit for detecting light in a two-dimensional shape in the imaging region so that a light emitting layer emitting light from the region irradiated with radiation overlaps the imaging region. Is arranged.

  And a part of light guide member is arrange | positioned in the detection object area | region which detects a radiation among light emitting layers, the light which generate | occur | produced in the detection object area | region is light-guided by the light guide member, and a light detection part by a light guide member The guided light is detected.

  As described above, according to the first aspect of the present invention, the region irradiated with radiation is emitted from the imaging region of the imaging panel in which pixels including the sensor unit for detecting light are provided in the imaging region in a two-dimensional manner. Since the light emitting layer is arranged so as to overlap, the light guide member is arranged in the detection target region for detecting radiation in the light emitting layer, and the light guided by the light guide member is detected. It is possible to detect radiation applied to a specific area in the imaging area.

  In the present invention, as in the invention according to claim 2, a plurality of the detection target regions are provided, and a plurality of the light guide members and the light detection units are provided corresponding to the detection target regions. Good.

  According to a second aspect of the present invention, as in the third aspect of the present invention, the photographing region is provided with an exposed portion that is not covered with the light emitting layer, and at least one of the light guide members is the photographing member. A part of the exposed portion of the region may be disposed to guide light to the exposed portion, and the pixel of the exposed portion of the photographing panel may function as the light detection unit.

  According to a third aspect of the present invention, as in the fourth aspect of the present invention, it is preferable that a light shielding member is provided on a surface of the light emitting layer facing the pixel functioning as the light detection unit.

  Further, in the invention described in claim 2 to claim 4, as in the invention described in claim 5, at least one of the light detection parts is configured to include an organic photoelectric conversion material, and is disposed on the side surface side of the light emitting layer. May be.

  Further, in the invention described in claims 2 to 5, as in the invention described in claim 6, the detection target area may be provided in at least two sizes.

  In the inventions according to claims 2 to 6, as in the invention according to claim 7, at least one of the detection target regions may be provided in a central portion and a peripheral portion of the imaging region.

  Further, according to the present invention, as in the invention described in claim 8, the detection is performed to detect any one of the radiation irradiation start, the radiation irradiation end, and the radiation irradiation amount based on the detection result by the light detection unit. Means may further be provided.

  Further, according to the first to eighth aspects of the present invention, as in the ninth aspect of the present invention, the imaging panel is light-transmitting, and radiation that has passed through the imaging panel is incident on the light emitting layer. The light guide member is disposed on the opposite side of the light emitting layer with the imaging panel interposed therebetween, and a gap is formed between the irradiated surface side member forming the irradiated surface of the housing and the imaging panel. May be sandwiched between the irradiated surface side member and the imaging panel.

  Further, according to a ninth aspect of the present invention, as in the tenth aspect of the present invention, the light incident on the light emitting layer side is arranged on the opposite side of the photographing panel with the light emitting layer interposed therebetween. You may further provide the 1st reflection part reflected to the side.

  Further, according to the first to eighth aspects of the present invention, as in the eleventh aspect of the present invention, the light emitting layer is formed by vapor deposition on a substrate having light transmittance and heat resistance, and is transmitted through the photographing panel. The radiation is incident, and the substrate is disposed on the opposite side of the photographing panel with the light emitting layer interposed therebetween, and the light guide member is disposed on the opposite side of the light emitting layer with the substrate interposed therebetween. May be.

  Further, according to an eleventh aspect of the present invention, as in the twelfth aspect of the present invention, a part of the light that is disposed between the substrate and the light guide member and is incident from the light emitting layer side is emitted. You may further provide the 2nd reflection part reflected in the layer side.

  The invention according to claims 1 to 12 includes an organic photoelectric conversion material as in the invention according to claim 13, and a plurality of second sensor units for detecting each irradiated light. And a detection panel arranged so as to overlap the light emitting layer or the imaging panel.

  Further, according to a thirteenth aspect of the present invention, as in the fourteenth aspect of the present invention, the imaging panel and the light emitting layer are configured such that the irradiated radiation passes through the imaging panel and enters the light emitting layer. The detection panel may be disposed on a surface of the photographing panel opposite to the light emitting layer.

  Further, in the invention of claim 13 or claim 14, as in the invention of claim 15, the irradiation start of radiation, the end of irradiation of radiation, and the irradiation of radiation are selectively performed using the light detection unit and the detection panel. You may further provide the detection means which detects either of quantity.

  On the other hand, in order to achieve the above object, the radiation imaging system according to claim 16 is configured to overlap an imaging panel in which pixels including a sensor unit for detecting light are provided in an imaging area in a two-dimensional manner, and the imaging area. A light emitting layer that emits light from a region irradiated with radiation, and a part of the light emitting layer that is disposed in a detection target region that detects radiation, and that guides light generated in the detection target region. One of a light member, a light detection unit that detects light guided by the light guide member, and a radiation irradiation start, a radiation irradiation end, and a radiation irradiation amount based on a detection result by the light detection unit Detecting means for performing detection.

  Therefore, according to the present invention, since it operates in the same manner as in the first aspect, it is possible to detect radiation irradiated to a specific region without providing defective pixels.

  According to the present invention, it is possible to detect radiation irradiated to a specific area without providing defective pixels.

It is a block diagram which shows the structure of the radiation information system which concerns on 1st Embodiment. It is a side view which shows an example of the arrangement | positioning state of each apparatus in the radiography room of the radiographic imaging system which concerns on 1st Embodiment. It is a permeation | transmission perspective view which shows the internal structure of the electronic cassette concerning 1st Embodiment. It is sectional drawing which showed typically the structure of the radiation detector and radiation detection part which concern on 1st Embodiment. It is sectional drawing which showed the structure of the thin-film transistor and capacitor | condenser of the radiation detector which concern on 1st Embodiment. It is a top view which shows the structure of the TFT substrate which concerns on 1st Embodiment. It is a top view which shows the arrangement configuration of the radiation detector inside the electronic cassette concerning 1st Embodiment. It is a side view which shows the structure inside the electronic cassette concerning 1st Embodiment. It is a block diagram which shows the principal part structure of the electric system of the electronic cassette concerning 1st Embodiment. It is a block diagram which shows the principal part structure of the electrical system of the console and radiation generator which concern on 1st Embodiment. It is a flowchart which shows the flow of a process of the imaging | photography control program which concerns on 1st Embodiment. It is a side view which shows the structure inside the electronic cassette concerning 2nd Embodiment. It is a block diagram which shows the principal part structure of the electric system of the electronic cassette concerning 2nd Embodiment. It is a flowchart which shows the flow of a process of the imaging | photography control program which concerns on 2nd Embodiment. It is a side view which shows the structure inside the electronic cassette concerning 3rd Embodiment. It is sectional drawing which showed typically the structure of the radiation detection part which concerns on 3rd Embodiment. It is a top view which shows the arrangement configuration of the sensor part of the radiation detection part which concerns on 3rd Embodiment. It is a block diagram which shows the principal part structure of the electric system of the electronic cassette concerning 3rd Embodiment. 12 is a flowchart illustrating a flow of processing of a shooting control program according to a third embodiment. It is a graph which shows the change of the value of the digital data of the electric signal output from a sensor part at the time of irradiation. It is a graph which shows the change of the total value when radiation is irradiated. It is a top view which shows the arrangement configuration of the radiation detector inside the electronic cassette which concerns on another form. It is a side view which shows the structure inside the electronic cassette which concerns on another form. It is a side view which shows the structure inside the electronic cassette which concerns on another form. It is a side view which shows the structure inside the electronic cassette which concerns on another form. It is a top view which shows the arrangement configuration of the sensor part of the radiation detection part which concerns on another form. It is sectional drawing which shows the arrangement configuration of the imaging | photography area | region and scintillator of the radiation detector which concerns on another form. It is a top view which shows the arrangement configuration of the imaging | photography area | region and scintillator of the radiation detector which concerns on another form. It is a side view which shows the structure inside the electronic cassette concerning 4th Embodiment. It is a side view which shows the structure inside the electronic cassette concerning 5th Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Here, a description will be given of an example in which the present invention is applied to a radiation image capturing system that captures a radiation image using a portable radiation imaging apparatus (hereinafter also referred to as “electronic cassette”).

[First Embodiment]
First, the configuration of a radiation information system (hereinafter referred to as “RIS (Radiology Information System)”) 10 according to the present embodiment will be described with reference to FIG.

  The RIS 10 is a system for managing information such as medical appointments and diagnosis records in the radiology department, and constitutes a part of a hospital information system (hereinafter referred to as “HIS (Hospital Information System)”). .

  The RIS 10 includes a plurality of radiography requesting terminal devices (hereinafter referred to as “terminal devices”) 12, a RIS server 14, and a radiographic imaging system (or an operating room) installed in a hospital. (Hereinafter referred to as “imaging system”) 18, which are connected to an in-hospital network 16, such as a wired or wireless LAN (Local Area Network). The RIS 10 constitutes a part of the HIS provided in the same hospital, and an HIS server (not shown) that manages the entire HIS is also connected to the in-hospital network 16.

  The terminal device 12 is used by doctors and radiographers to input and browse diagnostic information and facility reservations, and radiographic image capturing requests and imaging reservations are also made via the terminal device 12. Each terminal device 12 includes a personal computer having a display device, and is capable of mutual communication via the RIS server 14 and the hospital network 16.

  On the other hand, the RIS server 14 receives an imaging request from each terminal device 12 and manages a radiographic imaging schedule in the imaging system 18, and includes a database 14A.

  Database 14A includes patient (subject) attribute information (name, sex, date of birth, age, blood type, weight, patient ID (Identification), etc.), medical history, medical history, radiation images taken in the past, etc. Information related to the patient, identification number (ID information) of the electronic cassette 32 (to be described later) used in the imaging system 18, model, size, sensitivity, usable imaging part (content of imaging request that can be supported), date of start of use , Information on the electronic cassette 32 such as the number of times of use, and environment information indicating an environment in which a radiographic image is taken using the electronic cassette 32, that is, an environment in which the electronic cassette 32 is used (for example, a radiographic room or an operating room) It is comprised including.

  The imaging system 18 captures a radiographic image by an operation of a doctor or a radiographer according to an instruction from the RIS server 14. The imaging system 18 includes a radiation generator 34 that irradiates a subject with radiation X (see also FIG. 3) that is a dose according to the exposure conditions from a radiation source 130 (see also FIG. 2), and a subject. An electronic cassette incorporating a radiation detector 60 (see also FIG. 3) that generates radiation by absorbing the radiation X transmitted through the imaging region of the person and generates image information indicating a radiation image based on the amount of the generated charge. 32, a cradle 40 that charges a battery built in the electronic cassette 32, and an electronic cassette 32, a radiation generator 34, and a console 42 that controls the cradle 40.

  The console 42 acquires various types of information included in the database 14A from the RIS server 14 and stores them in an HDD 110 (see FIG. 10) described later. Based on the information, the electronic cassette 32, the radiation generator 34, and the cradle 40 are stored. Control.

  FIG. 2 shows an example of the arrangement state of each device in the radiation imaging room 44 of the imaging system 18 according to the present embodiment.

  As shown in the figure, the radiation imaging room 44 has a standing table 45 used when performing radiography in a standing position and a prone table 46 used when performing radiography in a lying position. The space in front of the standing base 45 is set as a subject imaging position 48 when performing radiography in the standing position, and the upper space of the prong position 46 is used in performing radiography in the prone position. The imaging position 50 of the subject.

  The standing base 45 is provided with a holding unit 150 that holds the electronic cassette 32, and the electronic cassette 32 is held by the holding unit 150 when a radiographic image is taken in the standing position. Similarly, a holding unit 152 that holds the electronic cassette 32 is provided in the prone position table 46, and the electronic cassette 32 is held by the holding unit 152 when radiographic images are taken in the prone position.

  Further, in the radiation imaging room 44, the radiation source 130 is arranged around a horizontal axis (see FIG. 5) in order to enable radiation imaging in a standing position and in a standing position by radiation from a single radiation source 130. 2 is provided, and a support moving mechanism 52 is provided which can be rotated in the vertical direction (arrow B direction in FIG. 2) and supported so as to be movable in the horizontal direction (arrow C direction in FIG. 2). It has been. Here, the support moving mechanism 52 includes a drive source that rotates the radiation source 130 about a horizontal axis, a drive source that moves the radiation source 130 in the vertical direction, and a drive source that moves the radiation source 130 in the horizontal direction. Each is provided (not shown).

  On the other hand, the cradle 40 is formed with an accommodating portion 40 </ b> A capable of accommodating the electronic cassette 32.

  When the electronic cassette 32 is not in use, the built-in battery is charged in a state of being accommodated in the accommodating portion 40A of the cradle 40. When a radiographic image is captured, the electronic cassette 32 is taken out from the cradle 40 by a radiographer or the like, and the imaging posture is established. If it is in the upright position, it is held in the holding part 150 of the standing table 45, and if it is in the upright position, it is held in the holding part 152 of the standing table 46.

  Here, in the imaging system 18 according to the present embodiment, the radiation generator 34 and the console 42 are connected by cables and various types of information are transmitted and received by wired communication. In FIG. The cable connecting 42 is omitted. Various information is transmitted and received between the electronic cassette 32 and the console 42 by wireless communication. The communication between the radiation generator 34 and the console 42 may be performed by wireless communication.

  The electronic cassette 32 is not used only in the state of being held by the holding portion 150 of the standing base 45 or the holding portion 152 of the standing base 46, and is not held by the holding portion because of its portability. It can also be used in the state.

  FIG. 3 shows an internal configuration of the electronic cassette 32 according to the present exemplary embodiment.

  As shown in the figure, the electronic cassette 32 includes a housing 54 made of a material that transmits the radiation X, and has a waterproof and airtight structure. When the electronic cassette 32 is used in an operating room or the like, there is a risk that blood and other germs may adhere. Therefore, one electronic cassette 32 can be used repeatedly by sterilizing and cleaning the electronic cassette 32 as necessary with a waterproof and airtight structure.

  A radiation detector 60 that captures a radiation image of the radiation X that has passed through the subject is disposed inside the housing 54.

  In addition, a case 31 that houses an electronic circuit including a microcomputer and a rechargeable battery 96 </ b> A is arranged on one end side inside the housing 54. The radiation detector 60 and the electronic circuit are operated by electric power supplied from the battery 96 </ b> A disposed in the case 31. In order to avoid various circuits housed in the case 31 from being damaged due to the radiation X, it is desirable to arrange a lead plate or the like on the imaging surface 56 side of the case 31. In addition, the electronic cassette 32 according to the present embodiment is a rectangular parallelepiped whose photographing surface 56 has a rectangular shape, and the case 31 is disposed at one end in the longitudinal direction.

  Further, at a predetermined position on the outer wall of the housing 54, a display unit 56A that displays an operation mode of the electronic cassette 32 such as an operation mode such as “ready state” and “data transmitting” and a remaining capacity of the battery 96A. Is provided. In the electronic cassette 32 according to the present embodiment, a light emitting diode is applied as the display unit 56A. However, the present invention is not limited to this, and other light emitting elements other than the light emitting diode, a liquid crystal display, an organic EL display, and the like are used. It may be a display means.

  FIG. 4 is a cross-sectional view schematically showing the configuration of the radiation detector 60 according to the present embodiment.

  The radiation detector 60 includes a TFT active matrix substrate (hereinafter referred to as “TFT substrate”) 66 in which a thin film transistor (TFT) 70 and a storage capacitor 68 are formed on an insulating substrate 64. I have.

  On the TFT substrate 66, a scintillator 71 that converts incident radiation into light is disposed.

  As the scintillator 71, for example, CsI: Tl, GOS (Gd2O2S: Tb) can be used. The scintillator 71 is not limited to these materials.

  The insulating substrate 64 may be any substrate as long as it has light transparency and low radiation absorption. For example, a glass substrate, a transparent ceramic substrate, or a light transmissive resin substrate can be used. The insulating substrate 64 is not limited to these materials.

  The TFT substrate 66 is formed with a sensor portion 72 that generates charges when light converted by the scintillator 71 is incident thereon. A flattening layer 67 for flattening the TFT substrate 66 is formed on the TFT substrate 66. An adhesive layer 69 for bonding the scintillator 71 to the TFT substrate 66 is formed between the TFT substrate 66 and the scintillator 71 and on the planarizing layer 67.

  The sensor unit 72 includes an upper electrode 72A, a lower electrode 72B, and a photoelectric conversion film 72C disposed between the upper and lower electrodes.

  The photoelectric conversion film 72 </ b> C absorbs light emitted from the scintillator 71 and generates a charge corresponding to the absorbed light. The photoelectric conversion film 72C may be formed of a material that generates charges when irradiated with light. For example, the photoelectric conversion film 72C may be formed of amorphous silicon, an organic photoelectric conversion material, or the like. The photoelectric conversion film 72C containing amorphous silicon has a wide absorption spectrum and can absorb light emitted by the scintillator 71. If the photoelectric conversion film 72C includes an organic photoelectric conversion material, it has a sharp absorption spectrum in the visible range, and electromagnetic waves other than light emitted by the scintillator 71 are hardly absorbed by the photoelectric conversion film 72C, and radiation such as X-rays. Is effectively suppressed by the photoelectric conversion film 72C being absorbed.

  In the present embodiment, the photoelectric conversion film 72C includes an organic photoelectric conversion material. Examples of the organic photoelectric conversion material include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength in the visible region of quinacridone is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 71, the difference in peak wavelength can be made within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 72C can be substantially maximized. Since the organic photoelectric conversion material applicable as the photoelectric conversion film 72C is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  FIG. 5 schematically shows the configuration of the TFT 70 and the storage capacitor 68 formed on the TFT substrate 66 according to the present embodiment.

  On the insulating substrate 64, corresponding to the lower electrode 72B, a storage capacitor 68 for storing the charge transferred to the lower electrode 72B, and a TFT 70 for converting the charge stored in the storage capacitor 68 into an electric signal and outputting it. Is formed. The region where the storage capacitor 68 and the TFT 70 are formed has a portion that overlaps with the lower electrode 72B in a plan view. With such a configuration, the storage capacitor 68 and the TFT 70 in each pixel portion, the sensor portion 72, and the like. Therefore, the storage capacitor 68, the TFT 70, and the sensor unit 72 can be arranged with a small area.

  The storage capacitor 68 is electrically connected to the corresponding lower electrode 72B through a wiring made of a conductive material formed through an insulating film 65A provided between the insulating substrate 64 and the lower electrode 72B. Yes. Thereby, the charges collected by the lower electrode 72B can be moved to the storage capacitor 68.

  In the TFT 70, a gate electrode 70A, a gate insulating film 65B, and an active layer (channel layer) 70B are stacked, and a source electrode 70C and a drain electrode 70D are formed on the active layer 70B at a predetermined interval. In the radiation detector 60, the active layer 70B is formed of an amorphous oxide. As the amorphous oxide constituting the active layer 70B, an oxide containing at least one of In, Ga, and Zn (for example, In—O-based) is preferable, and at least two of In, Ga, and Zn are used. An oxide containing In (for example, In—Zn—O, In—Ga, or Ga—Zn—O) is more preferable, and an oxide containing In, Ga, and Zn is particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO 3 (ZnO) m (m is a natural number of less than 6) is preferable, and InGaZnO 4 is particularly preferable. More preferred.

  If the active layer 70B of the TFT 70 is formed of an amorphous oxide, it will not absorb radiation such as X-rays, or even if it absorbs it, it will remain extremely small, effectively suppressing the generation of noise. Can do.

  Here, both the amorphous oxide constituting the active layer 70B of the TFT 70 and the organic photoelectric conversion material constituting the photoelectric conversion film 72C can be formed at a low temperature. Therefore, the insulating substrate 64 is not limited to a highly heat-resistant substrate such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate such as plastic, aramid, or bio-nanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. If such a plastic flexible substrate is used, it is possible to reduce the weight, which is advantageous for carrying around, for example. The insulating substrate 64 includes an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, and the like. May be provided.

  Since aramid can be applied at a high temperature process of 200 ° C. or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and can also be used for automatic mounting of a driver IC including a solder reflow process. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (indium tin oxide) or a glass substrate, warping after production is small and it is difficult to crack. In addition, aramid can form a substrate thinner than a glass substrate or the like. Note that the insulating substrate 64 may be formed by stacking an ultrathin glass substrate and aramid.

  Bionanofiber is a composite of cellulose microfibril bundles (bacterial cellulose) produced by bacteria (Acetobacter Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, 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 60-70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible, compared to glass substrates, etc. A thin insulating substrate 64 can be formed.

  FIG. 6 is a plan view showing the configuration of the TFT substrate 66 according to this embodiment.

  The TFT substrate 66 includes a pixel 74 including the sensor unit 72, the storage capacitor 68, and the TFT 70 described above in a certain direction (row direction in FIG. 6) and a crossing direction with respect to the certain direction (column direction in FIG. 6). Are provided two-dimensionally.

  The TFT substrate 66 includes a plurality of gate wirings 76 extending in a certain direction (row direction) for turning on / off the TFTs 70, and an on-state TFT 70 extending in a crossing direction (column direction). A plurality of data wirings 78 are provided for reading out charges through the wirings.

  The radiation detector 60 is flat and has a quadrilateral shape with four sides on the outer edge in plan view. Specifically, it is formed in a rectangular shape.

  As shown in FIG. 4, the radiation detector 60 according to this embodiment is formed by attaching a scintillator 71 to the surface of such a TFT substrate 66.

  The scintillator 71 is formed by vapor deposition on the vapor deposition substrate 73 when it is intended to be formed of columnar crystals such as CsI: Tl. Thus, when forming the scintillator 71 by vapor deposition, the vapor deposition substrate 73 is often an Al plate in terms of X-ray transmittance and cost, handling properties during vapor deposition, prevention of warpage due to its own weight, and deformation due to radiant heat. Therefore, a certain thickness (about several mm) is required. Note that when GOS is used as the scintillator 71, the scintillator 71 may be formed by applying GOS to the surface of the TFT substrate 66 without using the vapor deposition substrate 73.

  FIG. 7 is a plan view showing an arrangement configuration of the radiation detector 60 inside the electronic cassette 32 according to the first embodiment, and FIG. 8 shows a configuration inside the electronic cassette 32 according to the first embodiment. A side view is shown. In FIG. 8, the scintillator 71 is shown thicker than the actual thickness in order to make it easy to distinguish. Further, in FIG. 8, the imaging region 66 </ b> A is illustrated as a layer in order to easily identify the imaging region 66 </ b> A in which a plurality of pixels 74 of the TFT substrate 66 are provided two-dimensionally.

  As shown in FIG. 8, in the electronic cassette 32, a radiation detector 60 is affixed to the top plate portion constituting the imaging surface 56 of the housing 54 so that the TFT substrate 66 side is the top plate side.

  When the radiation detector 60 is irradiated with radiation (surface irradiation) from one surface side (upper side in FIG. 8) to which the scintillator 71 is attached, one surface side of the scintillator 71 (opposite side of the TFT substrate 66). When radiation is emitted from the other side (lower side in FIG. 8) (backside illumination), the radiation transmitted through the radiation detection unit 62 and the TFT substrate 66 enters the scintillator 71 and enters the scintillator 71. The TFT substrate 66 side emits light more intensely. Electric charges are generated by the light generated by the scintillator 71 in each sensor unit 72 provided on the TFT substrate 66. For this reason, the image capturing unit 21 is closer to the light emission position of the scintillator 71 with respect to the TFT substrate 66 when the radiation is irradiated from the other surface side than when the radiation is irradiated from the one surface side. The resolution of the obtained radiographic image is high.

  For this reason, a radiographic image with high resolution can be taken by attaching the radiation detector 60 to the top plate portion so that the TFT substrate 66 side becomes the top plate side.

  In the radiation detector 60, as shown in FIG. 7, the scintillator 71 is formed in a smaller size than the rectangular imaging region 66A in which a plurality of pixels 74 of the TFT substrate 66 are two-dimensionally provided. An exposed portion that is not covered with the scintillator 71 is provided in the periphery of the region 66A.

  A plurality of light guide members 170 are disposed on the surface of the scintillator 71 opposite to the TFT substrate 66 side. Each light guide member 170 is partly in contact with a detection target region 172 for detecting radiation in the imaging region 66A on the scintillator 71, and the other part is in contact with an exposed portion of the imaging region 66A of the TFT substrate 66. The light of the detection target region 172 of the scintillator 71 is guided to the exposed portion of the imaging region 66A of the TFT substrate 66. In order to prevent the light leaked from the light guide member 170 from entering the scintillator 71, the scintillator 71 is provided with the light shielding member 71A on the facing surface facing the contact portion between the light guide member 170 and the imaging region 66A. It may be.

  In general, the light guide member is made of acrylic or another material, and is a member that is subjected to special processing for preventing light leakage in a region other than a portion where light is incident or emitted on the surface of the member. In the first embodiment, the light guide member 170 is configured such that light incident from the portion in contact with the detection target region 172 is guided to the portion in contact with the radiation detector 60, and the radiation detector. The portion in contact with 60 is configured to emit light.

  By the way, when imaging is performed, the imaging region is generally arranged at the center of the rectangular imaging region 66A.

  For this reason, in the present embodiment, as shown in FIG. 7, detection target regions 172 </ b> A to 172 </ b> A including five central portions of the imaging region 66 </ b> A at predetermined intervals along one diagonal line of the rectangular imaging region 66 </ b> A. 172E, the size of the detection target region 172C in the central part is made larger than the other detection target regions 172A, 172B, 172D, and 172E, and the radiation dose is detected by the detection target region 172C in the central part, and the detection target region 172A , 172B, 172D, and 172E detect the start of radiation irradiation.

  In the TFT substrate 66 shown in FIG. 7, the direction of arrow A is the extending direction of the data wiring 78 (not shown), and the direction of arrow B is the extending direction of the gate wiring 76 (not shown). The light guide member 170C that guides light in the detection target region 172C contacts an exposed portion on one end side in the arrow A direction of the imaging region 66A of the radiation detector 60, and guides light in the detection target regions 172A, 172B, 172D, and 172E. The light guide members 170 </ b> A, 170 </ b> B, 170 </ b> D, and 170 </ b> E are in contact with the exposed portion on the other end side in the arrow A direction of the imaging region 66 </ b> A of the radiation detector 60.

  The exposed portions of the TFT substrate 66 that are in contact with the light guide members 170A, 170B, 170D, and 170E are not covered with the scintillator 71, but are provided with the pixels 74 because they are the imaging region 66A. The region 66A is connected to a predetermined number of gate wirings 76 on one end side and the other end side in the arrow A direction.

  FIG. 9 is a block diagram showing the main configuration of the electrical system of the electronic cassette 32 according to the first embodiment.

  As described above, the radiation detector 60 includes a plurality of pixels 74 including the sensor unit 72, the storage capacitor 68, and the TFT 70 arranged in a matrix, and the sensor unit according to the irradiation of the radiation X to the electronic cassette 32. The charges generated at 72 are stored in the storage capacitors 68 of the individual pixels 74. As a result, the image information carried on the radiation X irradiated to the electronic cassette 32 is converted into charge information and held in the radiation detector 60.

  The individual gate lines 76 of the radiation detector 60 are connected to a gate line driver 80, and the individual data lines 78 are connected to a signal processing unit 82.

  The gate line driver 80 according to the present embodiment can output a control signal for sequentially turning on the TFTs 70 to all the gate wirings 76 under the control of a cassette control unit 92 described later. As a result, a signal can be sequentially output to each gate wiring 76 of the radiation detector 60 to read out the accumulated charges from all the pixels 74. When charges are accumulated in the storage capacitors 68 of the individual pixels 74, the TFTs 70 of the individual pixels 74 are sequentially turned on in units of rows by a signal supplied from the gate line driver 80 through the gate wiring 76, and the TFTs 70 are turned on. The charges stored in the storage capacitor 68 of the pixel 74 are transmitted through the data wiring 78 as an analog electric signal and input to the signal processing unit 82. Therefore, the charges accumulated in the accumulation capacitors 68 of the individual pixels 74 are read out in order in row units.

  In addition, the gate line driver 80 according to the present embodiment can output a control signal for turning on the TFT 70 for a specific gate wiring 76 under the control of a cassette control unit 92 described later. In addition, each gate wiring 76 provided at an exposed portion on one end side of the imaging region 66A with which the light guide member 170C contacts, or exposure on the other end side of the imaging region 66A with which the light guide members 170A, 170B, 170D, and 170E contact. A control signal for turning on the TFT 70 can be individually output to each gate wiring 76 provided in the portion. Thereby, it is also possible to read out the accumulated charge from each pixel 74 in a region where the light guide member 170C is in contact and each pixel 74 in a region where the light guide members 170A, 170B, 170D, and 170E are in contact. .

  The signal processing unit 82 includes an amplifier and a sample-and-hold circuit provided for each data wiring 78, and an electric signal transmitted through each data wiring 78 is amplified by the amplifier and then held in the sample-and-hold circuit. The Further, a multiplexer and an A / D (analog / digital) converter are connected in order to the output side of the sample and hold circuit, and the electric signals held in the individual sample and hold circuits are sequentially (serially) input to the multiplexer. The digital data is converted by an A / D converter.

  An image memory 90 is connected to the signal processing unit 82, and digital data output from the A / D converter of the signal processing unit 82 is sequentially stored in the image memory 90. The image memory 90 has a storage capacity capable of storing image data for a plurality of frames. Every time a radiographic image is taken, digital data of each pixel 74 of the radiation detector 60 is used as image data. Are sequentially stored.

  The image memory 90 is connected to a cassette control unit 92 that controls the operation of the entire electronic cassette 32. The cassette control unit 92 includes a microcomputer, and includes a CPU (central processing unit) 92A, a memory 92B including a ROM (Read Only Memory) and a RAM (Random Access Memory), an HDD (Hard Disk Drive), and a flash memory. A non-volatile storage unit 92 </ b> C is provided.

  A wireless communication unit 94 is connected to the cassette control unit 92. The wireless communication unit 94 according to the present embodiment corresponds to a wireless LAN (Local Area Network) standard represented by IEEE (Institute of Electrical and Electronics Engineers) 802.11a / b / g and the like. Controls the transmission of various information to and from external devices. The cassette control unit 92 can wirelessly communicate with the console 42 via the wireless communication unit 94, and can transmit and receive various information to and from the console 42.

  The electronic cassette 32 is provided with a power supply unit 96, and the various circuits and elements described above (gate line driver 80, signal processing unit 82, image memory 90, wireless communication unit 94, cassette control unit 92, etc.) The power is supplied from the power supply unit 96. The power supply unit 96 incorporates the above-described battery (secondary battery) 96A so as not to impair the portability of the electronic cassette 32, and supplies power from the charged battery 96A to various circuits and elements. In FIG. 9, illustration of wirings connecting the power supply unit 96 to various circuits and elements is omitted.

  FIG. 10 is a block diagram showing the main configuration of the electrical system of the console 42 and the radiation generator 34 according to the present embodiment.

  The console 42 is configured as a server computer, and includes a display 100 that displays an operation menu, a captured radiation image, and the like, and a plurality of keys, and an operation panel on which various information and operation instructions are input. 102.

  The console 42 according to the present embodiment includes a CPU 104 that controls the operation of the entire apparatus, a ROM 106 that stores various programs including a control program in advance, a RAM 108 that temporarily stores various data, and various data. It includes an HDD 110 that stores and holds, a display driver 112 that controls display of various types of information on the display 100, and an operation input detection unit 114 that detects an operation state of the operation panel 102. In addition, the console 42 includes a communication interface (I / F) unit 116 that transmits and receives various types of information such as an exposure condition to be described later to and from the radiation generator 34 via the connection terminal 42A and the communication cable 35, and an electronic cassette. And a wireless communication unit 118 that transmits and receives various types of information such as exposure conditions and image data by wireless communication.

  The CPU 104, ROM 106, RAM 108, HDD 110, display driver 112, operation input detection unit 114, communication interface unit 116, and wireless communication unit 118 are connected to each other via a system bus BUS. Therefore, the CPU 104 can access the ROM 106, RAM 108, and HDD 110, controls display of various information on the display 100 via the display driver 112, and the radiation generator 34 via the communication I / F unit 116. And control of transmission / reception of various information to / from the radiation generator 34 via the wireless communication unit 118. Further, the CPU 104 can grasp the operation state of the user with respect to the operation panel 102 via the operation input detection unit 114.

  On the other hand, the radiation generator 34 controls the radiation source 130 based on the received radiation conditions and the communication I / F unit 132 that transmits and receives various information such as the radiation conditions between the radiation source 130 and the console 42. A radiation source control unit 134.

  The radiation source control unit 134 is also configured to include a microcomputer, and stores the received exposure conditions and the like. The exposure conditions received from the console 42 include information on tube voltage and tube current. The radiation source controller 134 irradiates the radiation X from the radiation source 130 based on the received exposure conditions.

  Next, the operation of the imaging system 18 according to the present embodiment will be described.

  The imaging system 18 according to the present embodiment can perform still image shooting that performs shooting one by one and fluoroscopic shooting that performs continuous shooting, and can select still image shooting or fluoroscopic shooting as a shooting mode. Has been.

  The terminal apparatus 12 (refer FIG. 1) receives the imaging request from a doctor or a radiographer, when imaging | photography of a radiographic image. In the imaging request, a patient to be imaged, an imaging region to be imaged, and an imaging mode are designated, and tube voltage, tube current, and the like are designated as necessary.

  The terminal device 12 notifies the RIS server 14 of the contents of the accepted imaging request. The RIS server 14 stores the contents of the imaging request notified from the terminal device 12 in the database 14A.

  The console 42 accesses the RIS server 14 to acquire the content of the imaging request and the attribute information of the patient to be imaged from the RIS server 14, and displays the content of the imaging request and the attribute information of the patient on the display 100 (see FIG. 10). .).

  The photographer starts radiographic image capturing based on the content of the imaging request displayed on the display 100.

  For example, as shown in FIG. 2, when photographing the affected part of the subject lying on the prone table 46, the electronic cassette 32 is disposed on the holding unit 152 of the prone table 46.

  Then, the photographer designates still image photographing or fluoroscopic photographing as the photographing mode for the operation panel 102, and further designates a tube voltage, a tube current, and the like when the operation panel 102 is irradiated with the radiation X.

  Here, for example, when the imaging system 18 connects the electronic cassette 32 and the console 42 or between the console 42 and the radiation generator 34 with a communication cable and transmits and receives information by wired communication, the layout of the apparatus is performed with the communication cable. It is preferable to transmit and receive information by wireless communication. However, when information is transmitted / received by wireless communication as described above, communication delay in wireless communication becomes a problem when shooting is performed in synchronization with each other by wireless communication.

  In the radiation detector 60, charges are generated in the sensor unit 72 due to dark current or the like even when X-rays are not irradiated, and the charges are stored in the storage capacitors 68 of the respective pixels 74.

  For this reason, in the electronic cassette 32 according to the present embodiment, when radiographic images are captured, the radiographic images are accumulated from the pixels 74 in the region where the light guide members 170A, 170B, 170D, and 170E are in contact with each other in the imaging region 66A. After detecting the start of radiation irradiation by repeatedly reading out the charged charges and detecting the start of radiation irradiation, after performing a reset operation to take out and remove the charge accumulated in the storage capacitor 68 of each pixel 74 of the radiation detector 60 Start shooting.

  Further, in the imaging system 18 according to the present embodiment, during imaging, the electric cassette 32 is repeatedly read out and the electronic cassette 32 is irradiated with the electric charge accumulated from the pixels 74 in the area where the light guide member 170C contacts in the imaging area 66A. The radiation amount is detected, and automatic irradiation control (so-called AEC (automatic exposure control)) is performed to control radiation irradiation from the radiation source 130 based on the detected radiation amount. Specifically, in the case of still image shooting, in the case of fluoroscopic imaging, when the detected radiation dose reaches an allowable amount, the irradiation end of radiation from the radiation source 130 and reading of the image from the radiation detector 60 are started. The imaging is continuously performed at a predetermined frame rate, and the radiation irradiation from the radiation source 130 is terminated when the radiation amount detected in the detection target region 172C in the central portion becomes an allowable amount. The allowable amount of still image shooting is an appropriate dose for taking a radiographic image of the imaging region clearly, and the allowable amount of fluoroscopic imaging is a dose for suppressing the exposure of the subject within an appropriate range, Each has a different purpose.

  The allowable amount of still image shooting and the allowable amount of fluoroscopic shooting may be input from the operation panel 102 by the photographer at the time of shooting. In addition, the permissible amount for still image photographing and the permissible amount for fluoroscopic photographing are stored in advance in the HDD 110 as per-photographing region permissible amount information for each photographing part, and the photographer designates the photographing part on the operation panel 102. When the imaging region is specified, the imaging mode and the allowable amount corresponding to the imaging region may be obtained from the imaging region allowable amount information. In addition, the permissible amount of fluoroscopic imaging is stored in the database 14A of the RIS server 14 so that the daily exposure dose is stored for each patient, and the RIS server 14 determines the exposure dose during a predetermined period (for example, the latest three months). The allowable exposure dose of the patient may be obtained from the total value, and the allowable exposure dose may be notified to the console 42 as the allowable dose.

  The console 42 transmits the specified tube voltage and tube current to the radiation generator 34 as exposure conditions, and transmits the specified imaging mode, tube voltage, tube current, and allowable amount to the electronic cassette 32 as imaging conditions. When the radiation source control unit 134 of the radiation generator 34 receives the exposure condition from the console 42, the received exposure condition is stored, and when the cassette control unit 92 of the electronic cassette 32 receives the imaging condition from the console 42, The received shooting conditions are stored in the storage unit 92C.

  When the photographer completes preparation for photographing, the photographer performs a photographing instruction operation for instructing photographing on the operation panel 102 of the console 42.

  When an imaging start operation is performed on the operation panel 102, the console 42 transmits instruction information for instructing the start of exposure to the radiation generator 34 and the electronic cassette 32.

  The radiation generator 34 starts generating and emitting radiation with a tube voltage and a tube current corresponding to the exposure conditions received from the console 42.

  When the cassette control unit 92 of the electronic cassette 32 receives the instruction information instructing the start of exposure, the cassette control unit 92 performs shooting control according to the shooting mode stored as the shooting condition in the storage unit 92C.

  FIG. 11 is a flowchart showing a flow of processing of the photographing control program executed by the CPU 92A of the cassette control unit 92. The program is stored in advance in a predetermined area of the memory 92B (ROM).

  In step S10 in the figure, the charge is read from each pixel 74 in the region where the light guide members 170A, 170B, 170D, and 170E are in contact.

  Specifically, the gate line driver 80 is controlled so that each gate wiring 76 provided at the exposed portion on the other end side of the imaging region 66A where the light guide members 170A, 170B, 170D, and 170E come into contact with the gate line driver 80 is connected. A control signal for turning on the TFT 70 is sequentially output. Thereby, in the radiation detector 60, the charges accumulated in the storage capacitors 68 of the respective pixels 74 connected to the gate wiring 76 passing through the exposed portion on the other end side of the imaging region 66A are supplied to the respective data wirings 78 as electric signals. The data is flown out, converted into digital data by the signal processing unit 82, and stored in the image memory 90.

  When the electronic cassette 32 is irradiated with radiation on any of the imaging surfaces 56, the radiation is converted into light in the region irradiated with the radiation of the scintillator 71. The light guide members 170A, 170B, 170D, and 170E guide the light converted in the detection target areas 172A, 172B, 172D, and 172E of the scintillator 71 to the periphery of the imaging area 66A, respectively. For this reason, it is possible to detect radiation in the detection target regions 172A, 172B, 172D, and 172E based on the digital data values of the pixels in the regions that are in contact with the light guide members 170A, 170B, 170D, and 170E.

  In the next step S12, among the digital data of each pixel 74 stored in the image memory 90, the digital data of each pixel 74 in the area where the light guide members 170A, 170B, 170D, and 170E are in contact is read and read. The digital data values are summed for each region where the light guide members 170A, 170B, 170D, and 170E are in contact. That is, binning is performed for each area by software. In this way, the sum of the digital data values of each pixel 74 for each region in which the light guide members 170A, 170B, 170D, and 170E are in contact improves the sensitivity to radiation.

  In the next step S14, the total value of the digital data for each region in contact with the light guide members 170A, 170B, 170D, 170E obtained in step S12 is compared with a predetermined radiation detection threshold value. The start of radiation irradiation is detected based on whether or not the threshold value is equal to or greater than the threshold value. If the total value of the digital data is equal to or greater than the threshold value, it is determined that radiation irradiation has started and the process proceeds to step S16. If the value of the digital data is less than the threshold value, the process shifts again to step S10 to wait for the start of radiation irradiation.

  In the next step S <b> 16, the gate line driver 80 is controlled so that the gate line driver 80 sequentially outputs a control signal for turning on the TFTs 70 to all the gate lines 76, and each TFT 70 connected to each gate line 76 is set to 1. The charge is taken out by sequentially turning on each line. As a result, in the radiation detector 60, the charges accumulated in the storage capacitors 68 of the respective pixels 74 in order line by line flow out to the respective data lines 78 as electric signals, and are accumulated in the storage capacitors 68 of the respective pixels 74 by dark current or the like. Charge is removed.

  In the next step S18, it is determined whether still image shooting is designated as the shooting mode under the shooting conditions stored in the storage unit 92C. If the determination is affirmative, the process proceeds to step S20, and in the case of a negative determination ( If fluoroscopic shooting is designated as the shooting mode), the process proceeds to step S40.

  In step S20, a control signal for controlling the gate line driver 80 to turn on the TFT 70 in each gate wiring 76 provided at an exposed portion on one end side of the imaging region 66A with which the light guide member 170C contacts from the gate line driver 80. Are sequentially output, and a control signal for turning off the TFT 70 is output to the other gate wirings 76. Thereby, in the radiation detector 60, the electric charge accumulated in the storage capacitor 68 of each pixel 74 connected to the gate wiring 76 that passes through the region in contact with the light guide member 170C flows out to each data wiring 78 as an electric signal, It is converted into digital data by the signal processing unit 82 and stored in the image memory 90.

  In the next step S22, among the digital data of each pixel 74 stored in the image memory 90, the values of the digital data of each pixel 74 in the area in contact with the light guide member 170C are summed.

  In the next step S24, the total value of the digital data of each pixel 74 in the region in contact with the light guide member 170C obtained in step S22 is accumulated. This cumulative value can be regarded as the radiation dose irradiated to the detection target region 172C.

  In the next step S26, it is determined whether or not the cumulative value obtained in step S22 is equal to or greater than the value according to the allowable amount of radiation. If the determination is affirmative, the process proceeds to step S28 and the determination is negative. If yes, the process proceeds to step S20.

  In step S28, instruction information for instructing the end of exposure to the console 42 is transmitted.

  When the console 42 receives the instruction information for instructing the end of exposure from the electronic cassette 32, the console 42 transmits the instruction information for instructing the end of exposure to the radiation generator 34. When receiving the instruction information for instructing the end of the exposure, the radiation generator 34 ends the radiation irradiation.

  In the next step S <b> 30, the gate line driver 80 is controlled so that an ON signal is sequentially output from the gate line driver 80 to all the gate lines 76 line by line.

  In the radiation detector 60, when the TFTs 70 connected to the gate wirings 76 are sequentially turned on line by line, the charges accumulated in the storage capacitors 68 sequentially line by line flow out to the data wirings 78 as electric signals. The electric signal flowing out to each data wiring 78 is converted into digital image data by the signal processing unit 82 and stored in the image memory 90.

  In the next step S32, the image data stored in the image memory 90 is transmitted to the console 42, and the process ends.

  On the other hand, in step S40, an imaging cycle corresponding to the perspective imaging frame rate is obtained.

  In the next step S42, the gate line driver 80 is controlled to turn on the TFT 70 in each gate wiring 76 provided on the exposed portion on one end side of the imaging region 66A where the light guide member 170C contacts from the gate line driver 80. The control signals are sequentially output, and the control signals for turning off the TFTs 70 are output to the other gate wirings 76. Thereby, in the radiation detector 60, the electric charge accumulated in the storage capacitor 68 of each pixel 74 connected to the gate wiring 76 that passes through the region in contact with the light guide member 170C flows out to each data wiring 78 as an electric signal, It is converted into digital data by the signal processing unit 82 and stored in the image memory 90.

  In the next step S44, among the digital data of each pixel 74 stored in the image memory 90, the values of the digital data of each pixel 74 in the region in contact with the light guide member 170C are summed.

  In the next step S46, the total value of the digital data of each pixel 74 in the region in contact with the light guide member 170C obtained in step S44 is accumulated. This cumulative value can be regarded as the radiation dose irradiated to the detection target region 172C.

  In the next step S48, it is determined whether or not the cumulative value obtained in step S46 is greater than or equal to the value according to the allowable amount of radiation. If the determination is affirmative, the process proceeds to step S60, and the determination is negative. If yes, the process proceeds to step S50.

  In step S50, it is determined whether or not a period equal to or longer than the imaging cycle has elapsed since the charge of each pixel 74 of the radiation detector 60 was read last time. If the determination is affirmative, the process proceeds to step S52. When it becomes negative determination, it transfers to step S42.

  In the next step S52, the gate line driver 80 is controlled to output an ON signal to each gate wiring 76 in order from the gate line driver 80 line by line.

  As a result, the radiation detector 60 sequentially turns on the TFTs 70 connected to the gate lines 76 line by line, and the charges accumulated in the storage capacitors 68 line by line flow out to the data lines 78 as electric signals. . The electric signal flowing out to each data wiring 78 is converted into digital image data by the signal processing unit 82 and stored in the image memory 90.

  In the next step S54, the digital data of each pixel 74 of the radiation detector 60 stored in the image memory 90 is transmitted as image data to the console 42. After the image data is transmitted, the process proceeds to step S42.

  On the other hand, in step S60, the instruction information for instructing the end of exposure is transmitted to the console 42, and the process is terminated.

  When receiving the instruction information for instructing the end of exposure, the radiation generator 34 ends the generation and emission of radiation. In the present embodiment, a case has been described in which the fluoroscopic imaging is stopped when the amount of radiation applied to the detection target region 172C provided in the central portion of the imaging region becomes an allowable amount during fluoroscopic imaging. However, the console 42 may be notified that the allowable amount has been exceeded, and a warning may be displayed on the console 42. Further, the console 42 transmits an exposure condition in which at least one of the tube voltage and the tube current is reduced to the radiation generator 34 to reduce the radiation dose per unit time irradiated from the radiation source 130 of the radiation generator 34. You may do it.

  When the console 42 receives image information from the electronic cassette 32, the console 42 performs various types of image processing such as shading correction on the received image information, and stores the image information after the image processing in the HDD 110.

  The image information stored in the HDD 110 is displayed on the display 100 for confirmation of the captured radiographic image, and is transferred to the RIS server 14 and stored in the database 14A. Thereby, it becomes possible for a doctor to perform interpretation, diagnosis, and the like of a radiographic image taken.

  Note that the radiation dose irradiated to the detection target region 172C can be regarded as the exposure dose of the subject. For this reason, when the daily exposure dose is stored for each patient in the database 14A of the RIS server 14, the electronic cassette 32 is transmitted to the RIS server 14 via the console 42 and stored in the database 14A. Thus, by storing and managing the daily exposure amount for each patient, the total exposure amount for a specific period can be grasped. Further, the exposure amount and the photographing conditions may be stored together in the database 14A. In this case, the electronic cassette 32 transfers the cumulative value (exposure amount) to the console 42, and the console 42 stores the cumulative amount (exposure amount) and the imaging conditions in association with each other in the database 14B. Thus, when the exposure amount and the imaging conditions are stored together, the utility value of the database 14B is further increased.

  As described above, according to the present embodiment, a region in which radiation is irradiated to the imaging region of the TFT substrate 66 in which the pixels 74 including the sensor unit 72 that detects light are two-dimensionally provided in the imaging region emits light. Since the scintillator 71 is arranged so as to overlap, the light guide member 170 is arranged in the detection target region 172 in which radiation is detected in the scintillator 71, and the light generated in the detection target region is detected by the light guide member 170. Without providing pixels, it is possible to detect radiation applied to a specific area in the imaging area.

  Further, according to the present embodiment, the light guide member 170 guides the light in the detection target region 172 to the exposed portion of the imaging region 66A of the radiation detector 60, and the pixel 74 in the exposed portion of the imaging region 66A is detected. Since it functions as a light detection unit that detects light in the region 172, it is possible to detect radiation without providing a separate light detection unit.

  Further, according to the present embodiment, the size of the detection target region 172C in the central portion of the imaging region 66A of the radiation detector 60 is larger than the detection target regions 172A, 172B, 172D, and 172E in the peripheral portion of the imaging region 66A. Therefore, it is possible to accurately detect the radiation dose transmitted through the imaging region.

[Second Embodiment]
Next, a second embodiment will be described.

  Since the configurations of the RIS 10, the imaging system 18, the electronic cassette 32, and the radiation detector 60 according to the second embodiment are the same as those in the first embodiment (see FIGS. 1 to 7 and FIG. 10), The description here is omitted.

  FIG. 12 is a side view showing the configuration inside the electronic cassette 32 according to the second embodiment. Note that the same parts as those in the first embodiment (FIG. 8) are denoted by the same reference numerals and description thereof is omitted.

  Inside the electronic cassette 32 according to the present exemplary embodiment, a light detection unit 180 that detects light is provided on the side surface. The light detection unit 180 may be a one-chip photodiode, a phototransistor, or a sensor that includes an organic photoelectric conversion material. In this embodiment, the light detection unit 180 is a sensor including an organic photoelectric conversion material.

  Since the light detection unit 180 configured to include such an organic photoelectric conversion material can be formed thin, it can be disposed in a small gap on the side surface, and can be formed at a low temperature, and thus can be formed on a flexible substrate such as plastic. it can. In addition, the light detection unit 180 configured to include an organic photoelectric conversion material is less deteriorated by radiation, has a stable performance, and is resistant to a drop impact.

  The other end side of the light guide member 170 </ b> C is in contact with the light detection unit 180. The light detection unit 180 detects light in the detection target region 172C via the light guide member 170C.

  FIG. 13 is a block diagram showing the main configuration of the electrical system of the electronic cassette 32 according to the first exemplary embodiment. Note that the same parts as those in the first embodiment (FIG. 9) are denoted by the same reference numerals and description thereof is omitted.

  The light detection unit 180 is connected to the cassette control unit 92. The cassette control unit 92 can grasp the detection result by the light detection unit 180.

  Further, in the electronic cassette 32 according to the present embodiment, at the time of shooting, the radiation amount irradiated is detected by detecting the light irradiated to the detection target region 172C by the light detection unit 180 via the light guide member 170C. Automatic irradiation control is performed to detect and control irradiation of radiation from the radiation source 130 based on the detected radiation dose.

  FIG. 14 is a flowchart showing the flow of processing of the shooting control program according to the second embodiment. Note that the same parts as those of the first embodiment (FIG. 11) are denoted by the same reference numerals and description thereof is omitted, and different parts are denoted by reference numeral A for description.

  In step S20A, the gate line driver 80 is controlled to output a control signal from the gate line driver 80 to each gate wiring 76 to turn off the TFT 70.

  In step S22A, the light detection unit 180 detects the amount of light.

  In step S24A, the amount of light detected in step 21A is accumulated. This cumulative value can be regarded as the exposure dose of the subject.

  In step S26A, it is determined whether or not the cumulative value of the light amount is equal to or larger than a value corresponding to the allowable amount. If the determination is affirmative, the process proceeds to step S28, and if the determination is negative, the process proceeds to step S22A. .

  On the other hand, in step S42A, the gate line driver 80 is controlled to output a control signal for turning off the TFT 70 to each gate wiring 76 from the gate line driver 80.

  In step S44A, the light detection unit 180 detects the amount of light.

  In step S46A, the amount of light detected in step 21A is accumulated.

  In step S48A, it is determined whether or not the cumulative value of the light amount is equal to or greater than a value corresponding to the allowable amount of radiation. If the determination is affirmative, the process proceeds to step S60, and if the determination is negative, the process proceeds to step S50A. Transition.

  In step S50A, it is determined whether or not a period equal to or longer than the imaging cycle has elapsed since the previous reading of the charge of each pixel 74 of the radiation detector 60. If the determination is affirmative, the process proceeds to step S52. If a negative determination is made, the process proceeds to step S44A.

  In step S54A, the digital data of each pixel 74 of the radiation detector 60 stored in the image memory 90 is transmitted as image data to the console 42. After the image data is transmitted, the process proceeds to step S44A.

  As described above, according to the present embodiment, the light guide member 170 guides the light in the detection target region 172 to the light detection unit 180, and the light detection unit 180 detects the light in the detection target region 172. The radiation applied to a specific region can be detected without providing defective pixels.

  Further, according to the present embodiment, by providing the light detection unit 180, it is possible to detect radiation without using the radiation detector 60.

[Third Embodiment]
Next, a third embodiment will be described.

  Since the configurations of the RIS 10, the imaging system 18, the electronic cassette 32, and the radiation detector 60 according to the third embodiment are the same as those of the first embodiment (see FIGS. 1 to 7 and FIG. 10), The description here is omitted.

  FIG. 15 is a side view showing the configuration inside the electronic cassette 32 according to the third embodiment. Note that the same parts as those in the first embodiment (FIG. 8) are denoted by the same reference numerals and description thereof is omitted. Further, in FIG. 15, a layer provided with a later-described sensor unit 146 of the radiation detection unit 62 is illustrated as a sensor layer 62A.

  The electronic cassette 32 according to the present embodiment is provided with only the light guide member 170C corresponding to the detection target region 172C in the center of the imaging region 66A. In the electronic cassette 32, a radiation detection unit 62 is disposed on the scintillator 71 side of the radiation detector 60 inside the housing 54.

  FIG. 16 is a cross-sectional view schematically showing the configuration of the radiation detection unit 62 according to the present embodiment.

  In the radiation detection unit 62, for example, a wiring layer 142 and an insulating layer 144 in which a wiring 160 (FIG. 18) described later is patterned are formed on a resin support substrate 140, and the radiation is detected thereon. A plurality of sensor portions 146 are formed. The sensor unit 146 includes an upper electrode 147A, a lower electrode 147B, and a photoelectric conversion film 147C disposed between the upper and lower electrodes. The photoelectric conversion film 147 </ b> C generates a charge when light converted by the scintillator 71 is incident thereon. The photoelectric conversion film 147C is preferably a photoelectric conversion film containing the above-described organic photoelectric conversion material, rather than a PIN-type or MIS-type photodiode using amorphous silicon. This is because it is better to use a photoelectric conversion film containing an organic photoelectric conversion material in terms of reduction in manufacturing cost and flexibility in comparison with the case of using a PIN type photodiode or a MIS type photodiode. Because it is advantageous. The sensor unit 146 of the radiation detector 62 does not need to be formed as finely as the sensor unit 72 provided in each pixel 74 of the radiation detector 60, and is formed with a size of tens to hundreds of pixels of the radiation detector 60. That's fine.

  FIG. 17 is a plan view showing a region where the sensor unit 146 of the radiation detection unit 62 is provided for the imaging region 66 </ b> A of the TFT substrate 66.

  The radiation detection unit 62 is provided with four sensor units 146 at positions near the four corners of the imaging region 66 </ b> A of the TFT substrate 66 when arranged inside the housing 54. Each sensor unit 146 is formed in the same size, and has substantially the same sensitivity to radiation. In the present embodiment, four sensor units 146 are provided, but the present invention is not limited to this. In addition, although the sensor unit 146 is disposed so as to be near the four corners of the imaging region 66A of the TFT substrate 66, the arrangement of the sensor unit 146 is not limited to this.

  FIG. 18 is a block diagram showing a main configuration of the electrical system of the electronic cassette 32 according to the third exemplary embodiment. Note that the same parts as those in the first embodiment (FIG. 8) are denoted by the same reference numerals and description thereof is omitted.

  The radiation detection unit 62 includes four sensor units 146. The radiation detection unit 62 is provided with a plurality of wirings 160 individually connected to the sensor unit 146, and each wiring 160 is connected to the signal detection unit 162.

  The signal detection unit 162 includes an amplifier and an A / D converter provided for each wiring 160, and is connected to the cassette control unit 92. The signal detection unit 162 performs sampling of each wiring 160 at a predetermined cycle by the control from the cassette control unit 92, converts the electrical signal transmitted through each wiring 160 into digital data, and sequentially converts the converted digital data, Output to the cassette control unit 92.

  FIG. 19 is a flowchart showing the flow of processing of the shooting control program according to the third embodiment. Note that the same parts as those of the first embodiment (FIG. 11) are denoted by the same reference numerals and description thereof is omitted, and different parts are denoted by reference numeral B for description.

  In step S10B, the signal detection unit 162 is controlled to start sampling of each wiring 160.

  As a result, the signal detection unit 162 samples each wiring 160 at a predetermined cycle, converts the electrical signal transmitted through each wiring 160 into digital data, and sequentially outputs the converted digital data to the cassette control unit 92. To do.

  Here, even when the imaging part is arranged on the imaging surface 56 of the electronic cassette 32, the imaging region of the imaging surface 56 is rarely covered with the imaging part, and is not covered with any imaging part of the four corners. This is a so-called blank region. In this blank area, since radiation does not pass through the imaging region, high energy radiation is irradiated. When each sensor unit 146 provided in the radiation detection unit 62 is irradiated with radiation, an electric charge is generated, and in particular, a large amount of electric charge is generated in the sensor unit 146 in the unexposed region. The generated charges flow out as electric signals to the wiring 160, respectively.

  In step S14B, the value of each digital data input from the signal detection unit 162 is compared with a predetermined threshold value for radiation detection, and the start of radiation irradiation is detected based on whether or not the threshold value is exceeded. If the digital data value is equal to or greater than the threshold value, the process proceeds to step S16 on the assumption that radiation irradiation has started. If the digital data value is less than the threshold value, the process proceeds to step S14B again. Wait for the start of irradiation.

  As described above, according to the present embodiment, the radiation detection unit 62 is disposed so as to overlap the scintillator 71, and light is detected by each sensor unit 146 of the radiation detection unit 62, thereby providing no defective pixels. Detection of radiation irradiated to a specific area can be performed.

  Further, according to the present embodiment, by providing the radiation detection unit 62, it is possible to detect radiation without using the radiation detector 60.

[Fourth Embodiment]
Next, a fourth embodiment will be described. The configurations of the radiation detector 60 of the RIS 10, the imaging system 18, and the electronic cassette 32 according to the fourth embodiment are the same as those in the first embodiment (see FIGS. 1 to 7 and 10). Therefore, the same reference numerals are given to the respective parts, and the description thereof is omitted. Hereinafter, the configuration of the electronic cassette 32 according to the fourth embodiment has been described in the first embodiment with reference to FIG. Only portions different from the electronic cassette 32 will be described.

  The scintillator 71 provided in the electronic cassette 32 preferably has a visible light wavelength range (wavelength 360 nm to 830 nm). In order to enable the radiation detector 60 to capture a monochrome radiographic image, More preferably, it includes a wavelength range. In the electronic cassette 32 according to the fourth exemplary embodiment, CsI (Tl) (thallium activated cesium iodide) having an emission spectrum of 420 nm to 700 nm at the time of X-ray irradiation is used as the scintillator 71. Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm.

  In the fourth embodiment, as shown in FIG. 29, the scintillator 71 is formed with a columnar crystal region including a columnar crystal 71A on the radiation incident side (radiation detector 60 side), opposite to the radiation incident side. The non-columnar crystal region including the non-columnar crystal 71B is formed on the side. In the scintillator 71 according to the fourth embodiment, the average diameter of the columnar crystal 71A is approximately uniform along the longitudinal direction of the columnar crystal 71A, and the tip of the columnar crystal 71A passes through the adhesive layer 120. Are adhered to the surface of the radiation detector 60. In addition, a partial reflection layer 122 is provided between the scintillator 71 and the vapor deposition substrate 73 to reflect a part of light incident from the scintillator 71 side to the scintillator 71 side and transmit the rest. The scintillator 71 having the above configuration is obtained by vapor-depositing CsI (Tl) on the vapor deposition substrate 73 on which the partial reflection layer 122 is formed.

  As described above, the scintillator 71 has a structure in which a columnar crystal region and a non-columnar crystal region are formed, and a columnar crystal region composed of the columnar crystal 71A from which high-efficiency light emission is obtained is disposed on the radiation detector 60 side. Thus, the light generated by the scintillator 71 travels through the columnar crystal 71A and is emitted to the radiation detector 60, and the diffusion of the light emitted to the radiation detector 60 side is suppressed, so that it is detected by the electronic cassette 32. The reduction in the sharpness of the radiographic image is suppressed. Further, the light reaching the deep part (non-columnar crystal region) of the scintillator 71 is partially reflected by the non-columnar crystal 71B and the partial reflection layer 122 toward the radiation detector 60, and is incident on the radiation detector 60. The amount of light (the detection efficiency of light emitted by the scintillator 71) is improved.

When the thickness of the columnar crystal region located on the radiation incident side of the scintillator 71 is t1, and the thickness of the non-columnar crystal region located on the vapor deposition substrate 73 side of the scintillator 71 is t2, t1 and t2 have the following relationship: It is preferable to satisfy the formula.
0.01 ≦ (t2 / t1) ≦ 0.25

  When the thickness t1 of the columnar crystal region and the thickness t2 of the non-columnar crystal region satisfy the above relational expression, a region that has high luminous efficiency and prevents light diffusion (columnar crystal region), and a region that reflects light (noncolumnar) The ratio of the scintillator 71 along the thickness direction of the scintillator 71 becomes a suitable range, and the light emission efficiency of the scintillator 71, the detection efficiency of the light emitted by the scintillator 71, and the resolution of the radiation image are improved. If the thickness t2 of the non-columnar crystal region is too thick, the region with low light emission efficiency increases and the sensitivity of the electronic cassette 32 is lowered. Therefore, (t2 / t1) is more preferably in the range of 0.02 or more and 0.1 or less. .

  The scintillator 71 has a structure in which a columnar crystal region and a non-columnar crystal region are continuously formed. For example, a partial reflection layer 122 is provided instead of the non-columnar crystal region, and only the columnar crystal region is formed. Other configurations may be used. In the fourth embodiment, the tip of the columnar crystal 71A is adhered to the surface of the radiation detector 60 via the adhesive layer 120, so that the radiation detector 60, the scintillator 71, and the vapor deposition in an integrated state are integrated. The outer periphery of the substrate 73 is covered with a sealing film 124.

  Further, in the electronic cassette 32 according to the fourth embodiment, similarly to the electronic cassette 32 according to the first embodiment described above, the back surface of the vapor deposition substrate 73 (opposite to the surface on which the scintillator 71 is formed). The light guide member 170 is provided in the detection target region on the side surface. For this reason, in the fourth embodiment, the vapor deposition substrate 73 is a substrate having light transmittance in addition to heat resistance so that a part of the light emitted from the scintillator 71 enters the light guide member 170. Is used. The light guide member 170 guides incident light to a portion of the imaging region 66A of the radiation detector 60 that is not covered with the scintillator 71, as in the first embodiment, and the first Similarly to the second embodiment, any configuration of guiding light to the light detection unit 180 may be used.

  As materials applied to the vapor deposition substrate 73 having heat resistance and light transmittance, the materials listed below are suitable. For example, transparent polyimide film (AIST Co., Ltd., “Highly transparent plastic film that can withstand −150 ° C. to 300 ° C.”, [online], [searched July 26, 2011], Internet <URL: http: // www. istcorp.jp/div_el_cpifl.htm>, <URL: http://www.kiis.or.jp/number1/pdf/10_rntHg.pdf>) is preferable. Also, for example, U polymer (PAR) (Unitika Ltd., “What is U polymer”, [online], [searched July 26, 2011], Internet <URL: http://www.unitika.co.jp /plastics/upolymer/index.html>) is also suitable. Also, for example, transparent plastic substrate material for flexible display (OPS) (Tosoh Corporation, “Development of transparent plastic substrate material for flexible display”, [online], [searched July 26, 2011], Internet <URL: http http://www.tosoh.co.jp/technology/report/pdfs/2006_03_02.pdf>) is also suitable. Also, for example, a flame-retardant colorless and transparent aramid film (Nikkei BP, "Nanotech Exhibition" Can be used for flexible display substrates "), Toray develops a halogen-free and flame-retardant colorless and transparent aramid film ”, [Online], [Search July 26, 2011], Internet <URL: http://techon.nikkeibp.co.jp/article/NEWS/20100210/180135/?ST=print>) is also suitable Needless to say, the material applied to the vapor deposition substrate 73 may be a material having heat resistance and light transmittance, and materials other than those described above can also be applied.

  As described above, since the vapor deposition substrate 73 has light transmittance, a part of the light emitted from the scintillator 71 is transmitted through the partial reflection layer 122 and the vapor deposition substrate 73 in order, and among these, the detection target region is defined. The transmitted light is incident on the light guide member 170. As a result, the light that has passed through the detection target region and is incident on the light guide member 170 is guided by the light guide member 170 and detected by the radiation detector 60 or the light detection unit 180, so that the detection target region is detected. The radiation applied to the corresponding specific area is detected.

[Fifth Embodiment]
Next, a fifth embodiment will be described. The configurations of the radiation detector 60 of the RIS 10, the imaging system 18, and the electronic cassette 32 according to the fifth embodiment are the same as those of the first embodiment (see FIGS. 1 to 7 and 10). Therefore, the same reference numerals are given to the respective parts, and the description thereof is omitted. Hereinafter, the configuration of the electronic cassette 32 according to the fifth embodiment has been described in the fourth embodiment with reference to FIG. Only portions different from the electronic cassette 32 will be described.

  As shown in FIG. 30, in the scintillator 71 according to the fifth embodiment, a columnar crystal region is formed on the radiation incident side (radiation detector 60 side), as in the fourth embodiment. A non-columnar crystal region is formed on the side opposite to the side. In the electronic cassette 32 according to the fifth embodiment, the light guide member 170 is provided on the opposite side of the scintillator 71 with the radiation detector 60 interposed therebetween, and a part of the light emitted from the scintillator 71 is obtained. There is no need to inject the vapor deposition substrate to the opposite side.

  For this reason, in the fifth embodiment, as the vapor deposition substrate 128 on which the scintillator 71 is formed, instead of having heat resistance and not light transmittance, a low-cost material (for example, aluminum is suitable). Is used. Further, in the fifth embodiment, instead of the partial reflection layer 122 described in the fourth embodiment, total reflection that reflects light transmitted through the non-columnar crystal region of the scintillator 71 to the radiation detector 60 side. A layer 126 is provided. As a result, the amount of light incident on the radiation detector 60 (detection efficiency of light emitted by the scintillator 71) is further improved.

  Also in the fifth embodiment, the tip of the columnar crystal 71A is bonded to the surface of the radiation detector 60 via the adhesive layer 120, so that the radiation detector 60 and the scintillator are in an integrated state. 71 and the outer periphery of the vapor deposition substrate 128 are covered with a sealing film 124.

  In the electronic cassette 32 according to the fifth embodiment, the light guide members 170 are attached to a plurality of locations on the back surface of the radiation detector 60 (the surface opposite to the scintillator 71 with the radiation detector 60 in between). It has been. For this reason, in the fifth embodiment, the radiation detector 60 is configured to have optical transparency (for example, as the insulating substrate 64, a glass substrate having optical transparency and low radiation absorption, Transparent ceramic substrate, light transmissive resin substrate, etc.). Thereby, in the fifth embodiment, a part of the light emitted from the scintillator 71 passes through the radiation detector 60 and enters the light guide member 170.

  The light guide member 170 guides incident light to a portion of the imaging region 66A of the radiation detector 60 that is not covered with the scintillator 71, as in the first embodiment, and the first Similarly to the second embodiment, any configuration of guiding light to the light detection unit 180 may be used. As a result, light transmitted through the radiation detector 60 and incident on the individual light guide members 170 is guided by the individual light guide members 170 and detected by the radiation detector 60 or the light detection unit 180. Thus, radiation exposure is detected.

  In addition, each light guide member 170 attached to the back surface of the radiation detector 60 has the back surface of the top plate 31 </ b> A of the case 31 in which the surface opposite to the surface attached to the radiation detector 60 forms the imaging surface 56. The adhesive layer 136 is adhered to (the surface opposite to the imaging surface 56). Thereby, the radiation detector 60 is affixed on the back surface of the top plate 31 </ b> A via the light guide member 170. As described above, when the radiation detector 60 to which the scintillator 71 is bonded is attached to the back surface of the top board 31A, the weight of the patient (subject) body weight is passed through the radiation detector 60 when the radiation image is taken. 71 is applied as a load.

  In contrast, in the fifth embodiment, light guide members 170 are provided at a plurality of locations between the top plate 31A and the radiation detector 60. Thereby, at the time of taking a radiographic image, the top plate 31A of the part where the light guide member 170 is not provided between the radiation detector 60 is slightly bent by the weight of the body of the patient (subject), The load applied to the scintillator 71 is reduced. Therefore, it is possible to prevent damage to the columnar crystal region of the scintillator 71 due to the load applied to the scintillator 71.

  Further, when the radiation detector 60 is attached to the back surface of the top plate 31 </ b> A, the body temperature of the patient (subject) is conducted to the radiation detector 60 when a radiation image is taken. Here, when the insulating substrate 64 of the radiation detector 60 is formed of a glass substrate having low thermal conductivity, temperature unevenness occurs in the radiation detector 60, and dark current unevenness of the sensor unit 72 that changes depending on the temperature is generated. As a result, there arises a problem that the image quality of the radiation image is uneven.

  In contrast, in the fifth embodiment, light guide members 170 are provided at a plurality of locations between the top plate 31A and the radiation detector 60, and between the top plate 31A and the radiation detector 60. A gap is formed. Thereby, the heat conducted from the top plate 31A side is diffused by the light guide member 170 and the gap existing between the top plate 31A and the radiation detector 60, and the temperature unevenness of the radiation detector 60 is reduced. The unevenness of the image quality of the radiation image is also remarkably suppressed.

  In addition, in the 4th and 5th embodiment mentioned above, you may further provide the radiation detection part 62 demonstrated in 3rd Embodiment. In this case, similarly to the third embodiment, the radiation start may be detected by the radiation detection unit 62, and the accumulated radiation dose may be detected by the light guided by the light guide member 170. Alternatively, the start of radiation irradiation may be detected by the light guided by the light guide member 170, and the cumulative radiation dose may be detected by the radiation detection unit 62.

  As mentioned above, although this invention was demonstrated using the 1st-5th embodiment, the technical scope of this invention is not limited to the range as described in each said embodiment. Various modifications or improvements can be added to the above-described embodiments without departing from the gist of the invention, and embodiments to which the modifications or improvements are added are also included in the technical scope of the present invention.

  The above embodiments do not limit the invention according to the claims (claims), and all the combinations of features described in the embodiments are essential for the solution means of the invention. Is not limited. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in each of the above embodiments, the case where the present invention is applied to the electronic cassette 32 which is a portable radiation imaging apparatus has been described. However, the present invention is not limited to this, and a stationary radiation imaging apparatus is provided. You may apply to.

  Moreover, although each said embodiment demonstrated the case where the irradiation start of a radiation and the irradiation amount of a radiation were detected, this invention is not limited to this. For example, the end of radiation irradiation may be detected. As shown in FIG. 20A, the end of radiation irradiation is the total value of digital data for each region that the light guide members 170A, 170B, 170D, and 170E are in contact with, and each sensor unit 146 that is input from the signal detection unit 162. The value of the digital data is compared with a predetermined threshold value for radiation detection, and detection can be made based on whether or not the value is less than the threshold value. As shown in FIG. 20B, the threshold value may be made different depending on the detection of the start of irradiation and the end of irradiation. In FIG. 20B, the irradiation start threshold is larger than the irradiation end threshold, but the irradiation start threshold may be smaller than the irradiation end threshold. In this way, by providing hysteresis to the detection of the start and end of irradiation, it is possible to detect the start and end of irradiation while suppressing the influence of noise and the like. For example, charges are generated in the sensor unit 72 and the sensor unit 146 by irradiation of irradiation rays, but a part of the charges generated in the sensor unit 72 and the sensor unit 146 is temporarily trapped, and radiation irradiation ends. When charges trapped from the sensor unit 72 and the sensor unit 146 later flow out as electrical signals to the wiring 160, the irradiation end can be detected quickly by increasing the irradiation end threshold.

  Further, as shown at T1 in FIG. 21, the end of irradiation can be detected when there is an inflection point at which the increase amount of the cumulative value greatly decreases.

  In the first embodiment, as shown in FIG. 7, a light guide member 170C that guides light in the detection target region 172C by disposing a scintillator 71 having a size smaller than that of the shooting region 66A in the center of the shooting region 66A. Is brought into contact with an exposed portion on one end side in the arrow A direction of the imaging region 66A, and the light guide members 170A, 170B, 170D, and 170E that guide light in the detection target regions 172A, 172B, 172D, and 172E are in the arrow A direction of the imaging region 66A. Although the case where it was made to contact along with the exposed part of the other end side of this was demonstrated, this invention is not limited to this. For example, as shown in FIG. 22, a light guide member that arranges a scintillator 71 having a size smaller than that of the imaging region 66A toward one end side in the direction of arrow A of the imaging region 66A and guides light in the detection target region 172C in the center portion. 170C and light guide members 170A, 170B, 170D, and 170E that guide light in the detection target regions 172A, 172B, 172D, and 172E are brought into contact with each other along the exposed portion on the other end side in the arrow A direction of the imaging region 66A. Good. Thus, the detection of the radiation in the detection target regions 172A to 172E is performed by sequentially outputting a control signal for turning on the TFT 70 to each gate wiring 76 provided in the exposed portion on the other end side in the arrow A direction. be able to.

  In each of the above embodiments, when the radiation image is read, the ON signal is sequentially applied to all the gate wirings 76 in order, including all the gate wirings 76 including the gate wiring 76 provided in the exposed portion of the imaging region 66A. However, the present invention is not limited to this. For example, the ON signal may be output in order for each gate wiring 76 excluding the exposed portion one line at a time. In such a case, for example, a gate line driver for controlling the gate wiring 76 provided in the exposed portion may be provided separately from the gate line driver 80.

  In each of the above-described embodiments, the case where the ON signal is sequentially output to each gate wiring 76 provided in the exposed portion on one end side and the other end side of the imaging region 66A has been described. It is not limited to. For example, when detecting radiation in the detection target regions 172A, 172B, 172D, and 172E, an ON signal is simultaneously output to each gate wiring 76 provided in the exposed portion on the other end side of the imaging region 66A, and the detection target When detecting radiation in the region 172C, an ON signal may be simultaneously output to each gate wiring 76 provided in the exposed portion on one end side of the imaging region 66A. When ON signals are simultaneously output to the plurality of gate wirings 76, the TFTs 70 of the respective pixels 74 are turned on by the plurality of gate wirings 76 through which the ON signals flow, and are stored in the storage capacitors 68 of the plurality of pixels 74 in the respective data wirings 78. Since the generated charges collectively flow as an electric signal, binning is performed in an analog manner.

  Further, in the third embodiment, as shown in FIG. 15, only the light guide member 170C corresponding to the detection target region 172C in the central portion of the imaging region 66A is provided, and the radiation in the peripheral portion of the imaging region 66A is radiated. Although the case of detecting by the detection unit 62 has been described, the present invention is not limited to this. For example, as shown in FIG. 23, only the light guide member 170A corresponding to the detection target region 172A in the peripheral portion of the imaging region 66A may be provided, and the radiation in the central portion of the imaging region 66A may be detected by the radiation detection unit 62. Good. When the radiation detector 60 has optical transparency, the radiation detector 62 may be disposed on the surface opposite to the scintillator 71 as shown in FIGS. The radiation detector 62 detects the light of the scintillator 71 that has passed through the radiation detector 60. By forming the sensor unit 146 with a photoelectric conversion film containing an organic photoelectric conversion material, absorption of radiation by the sensor unit 146 of the radiation detection unit 62 can be suppressed.

  In the first embodiment, the case where five detection target regions 172 are provided has been described. However, the present invention is not limited to this. Further, the present invention is not limited to the arrangement of the detection target region 172, and it is sufficient that at least one of the central portion and the peripheral portion of the imaging region is disposed.

  In the above description, the case where the cassette control unit 92 of the electronic cassette 32 starts radiation irradiation, ends radiation irradiation, and detects the radiation dose is described, but the present invention is not limited to this. . For example, it is assumed that the cassette control unit 92 transmits digital data input from the signal detection unit 162 to the console 42 as needed, and the console 42 performs radiation irradiation start, radiation irradiation end, and radiation dose detection. Also good.

  In the third embodiment, the case where four sensor units 146 are provided in the radiation detection unit 62 has been described. However, the present invention is not limited to this. Further, the present invention is not limited to the arrangement of the sensor unit 146, and it is sufficient that at least one of the central part and the peripheral part of the imaging region is arranged. For example, as shown in FIG. 26, the sensor units 146 may be arranged in a matrix in the imaging region. FIG. 26 shows an example in which the sensor units 146 are arranged in a 4 × 5 matrix.

  Further, in each of the above embodiments, for example, as shown in FIG. 7, the scintillator 71 is formed in a size smaller than the imaging region 66A, and an exposed portion that is not covered with the scintillator 71 is provided around the imaging region 66A. However, the present invention is not limited to this. For example, even when the scintillator 71 is formed in a size larger than the imaging area 66A, as shown in FIG. 27, the scintillator 71 is shifted to one side in parallel with the imaging area 66A, thereby arranging the other side of the imaging area 66A. The peripheral portion may be an exposed portion not covered with the scintillator 71. In addition, as shown in FIG. 28, the shape of the scintillator 71 may be deformed to provide the recess 200 so that an exposed portion that is not covered by the scintillator 71 is provided at the periphery of the imaging region 66A.

  Moreover, although each said embodiment demonstrated the case where this invention was applied to the radiography apparatus which image | photographs a radiographic image by detecting an X-ray as a radiation, this invention is not limited to this. For example, the radiation to be detected may be any of visible light, ultraviolet rays, infrared rays, gamma rays, particle rays, etc. in addition to X-rays.

  In addition, the configuration described in each of the above embodiments is an example, and an unnecessary part is deleted, a new part is added, or a connection state is changed without departing from the gist of the present invention. It goes without saying that you can do it.

  Furthermore, the processing flow of the various programs described in the above embodiments is also an example, and unnecessary steps can be deleted, new steps can be added, and the processing order can be added without departing from the gist of the present invention. Needless to say, can be replaced.

18 Imaging System 32 Electronic Cassette 56 Imaging Surface 60 Radiation Detector 62A Sensor Layer 62 Radiation Detection Unit (Detection Panel)
66 TFT substrate (photographing panel)
66A Shooting area 71 Scintillator (light emitting layer)
71A Light-shielding member 72 Sensor part 74 Pixel (light detection part)
92 Cassette control unit (detection means)
92A CPU
146 Sensor unit (second sensor unit)
170 Light guide member 172 Detection target region 180 Photodetection unit

Claims (16)

An imaging panel in which pixels including a sensor unit for detecting light in an imaging area are provided in a two-dimensional manner;
A light emitting layer disposed so as to overlap the imaging region and emitting a region irradiated with radiation;
A light guide member that guides light generated in the detection target region, a part of which is disposed in the detection target region that detects radiation in the light emitting layer,
A light detection unit for detecting light guided by the light guide member;
A radiography apparatus comprising: A plurality of the detection target regions are provided,
The radiation imaging apparatus according to claim 1, wherein a plurality of the light guide member and the light detection unit are provided corresponding to the detection target region. The shooting area is provided with an exposed portion not covered with the light emitting layer,
At least one of the light guide members is partially disposed in the exposed portion of the imaging region and guides light to the exposed portion,
The radiation imaging apparatus according to claim 2, wherein pixels of the exposed portion of the imaging panel function as the light detection unit. The radiation imaging apparatus according to claim 3, wherein the light emitting layer is provided with a light shielding member on a surface facing the pixel functioning as the light detection unit. The radiation imaging apparatus according to claim 2, wherein at least one of the light detection units includes an organic photoelectric conversion material and is disposed on a side surface side of the light emitting layer. The radiation imaging apparatus according to claim 2, wherein the detection target area is provided in at least two sizes. The radiation imaging apparatus according to any one of claims 2 to 6, wherein at least one of the detection target areas is provided in a central part and a peripheral part of the imaging area. The detector according to any one of claims 1 to 7, further comprising detection means for detecting any one of radiation start, radiation end, and radiation dose based on a detection result by the light detection unit. The radiation imaging apparatus described. The photographing panel has light transparency,
The light emitting layer is disposed so that radiation transmitted through the imaging panel is incident thereon,
The light guide member is disposed on the opposite side of the light emitting layer with the photographing panel interposed therebetween, and a gap is formed between the photographing surface side member forming the illuminated surface of the housing and the photographing panel. The radiation imaging apparatus according to claim 1, wherein the radiation imaging apparatus is sandwiched between the irradiated surface side member and the imaging panel.   The radiation imaging apparatus according to claim 9, further comprising a first reflecting unit that is disposed on the opposite side of the imaging panel with the light emitting layer interposed therebetween and reflects light incident from the light emitting layer side to the light emitting layer side. The light emitting layer is formed by vapor deposition on a light transmissive and heat resistant substrate, the radiation transmitted through the imaging panel is incident, and the substrate is positioned on the opposite side of the imaging panel with the light emitting layer interposed therebetween. Arranged as
The radiation imaging apparatus according to claim 1, wherein the light guide member is disposed on the opposite side of the light emitting layer with the substrate interposed therebetween.   The radiographic imaging according to claim 11, further comprising a second reflecting portion that is disposed between the substrate and the light guide member and reflects part of light incident from the light emitting layer side to the light emitting layer side. apparatus. A plurality of second sensor units configured to include an organic photoelectric conversion material, each of which detects irradiated light, and further including a detection panel disposed so as to overlap the light emitting layer or the imaging panel. The radiation imaging apparatus according to any one of claims 1 to 12. The imaging panel and the light emitting layer are arranged such that irradiated radiation passes through the imaging panel and enters the light emitting layer,
The radiation imaging apparatus according to claim 13, wherein the detection panel is disposed on a surface of the imaging panel opposite to the light emitting layer. The radiographic imaging according to claim 13 or 14, further comprising a detection unit that detects any one of radiation start, radiation end, and radiation dose by properly using the light detection unit and the detection panel. apparatus. An imaging panel in which pixels including a sensor unit for detecting light in an imaging area are provided in a two-dimensional manner;
A light emitting layer disposed so as to overlap the imaging region and emitting a region irradiated with radiation;
A light guide member that guides light generated in the detection target region, a part of which is disposed in the detection target region that detects radiation in the light emitting layer,
A light detection unit for detecting light guided by the light guide member;
Detecting means for detecting any one of radiation start, radiation end, and radiation dose based on a detection result by the light detection unit;
A radiation imaging system having

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