JP2012032182A - Radiographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiographic device capable of detecting radiation and controlling a radiation source even when narrowing an irradiation range of the radiation down to a photograph area or a part of the photograph area.SOLUTION: In the radiographic device provided with a scintillator 71 which generates light by irradiation of radiation to a photograph area, a plurality of pixels 74a are provided in a matrix form so that the pixels are overlapped with the scintillator 71 and at least a part of a sensor portion 72 for photographing a radiation image and a sensor portion 146 for detecting radiation are not overlapped with each other.

Description

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

  In recent years, radiation detectors such as flat panel detectors (FPDs) that can arrange radiation sensitive layers on TFT (Thin Film Transistor) active matrix substrates and convert radiation directly into digital data have been put into practical use. A radiographic apparatus that captures a radiographic image represented by irradiated radiation has been put to 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, GOS (Gd ₂ O ₂ S: Tb), and converted light. Materials that can be used for the semiconductor layer in each method, such as an indirect conversion method that converts the charge into a charge using a sensor such as a photodiode, and a direct conversion method that converts radiation into a charge in a semiconductor layer such as amorphous selenium. There are various types. 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 radiography apparatus, there is a technology for providing a sensor unit for detecting radiation separately from the radiation detector, detecting the start and end of radiation irradiation, detecting the radiation dose, and controlling the radiation source for radiating the radiation. For example, in Patent Document 1, a sensor unit that detects radiation is provided beside a radiation detector (described as a solid-state imaging device), and the start and end of radiation emission are detected by the sensor unit to detect radiation. A technique for controlling the accumulation of electric charges in a vessel and the reading of accumulated electric charges is disclosed.

JP 2002-181942 A

  However, when a sensor unit for detecting radiation is provided beside the radiation detector as in Patent Document 1, the radiation irradiation range is narrowed down to an imaging region for capturing a radiation image of the radiation detector or a part of the imaging region. In the case of radiation.

  The present invention has been made in view of the above-described facts, and even when the radiation irradiation range is narrowed down to an imaging region or a part of the imaging region, radiation imaging capable of detecting radiation and controlling the radiation source An object is to provide an apparatus.

  In order to achieve the above object, the radiation imaging apparatus according to claim 1 is provided with a light emitting layer that generates light by irradiating radiation to an imaging region where a radiographic image is captured, and each is irradiated with light. A plurality of pixels formed so that at least a portion of the first sensor unit for radiographic imaging and the second sensor unit for radiation detection that generate electric charges do not overlap at least partially overlap with the light emitting layer. An imaging unit is provided.

  According to the first aspect of the present invention, the imaging unit is provided with a light emitting layer that generates light when radiation is applied to an imaging region where radiographic images are captured.

  The imaging unit is at least partially overlapped with a first sensor unit for radiographic imaging and a second sensor unit for radiation detection that generate electric charges when irradiated with light so as to overlap the light emitting layer. A plurality of pixels formed so as not to be formed are provided in a matrix.

  As described above, according to the first aspect of the present invention, the first sensor for radiographic imaging is provided so that the imaging region is provided with the light emitting layer that generates light when irradiated with radiation, and overlaps the light emitting layer. Since the plurality of pixels formed so that at least a part of the first sensor unit and the second sensor unit for detecting radiation do not overlap each other are provided in a matrix, the radiation irradiation range is limited to the imaging region or a part of the imaging region. Even in such a case, the radiation source can be controlled by detecting the radiation with the second sensor unit.

  In the present invention, as in the invention described in claim 2, it is preferable that the second sensor unit includes an organic photoelectric conversion material.

  Further, according to the present invention, as in the invention described in claim 3, each pixel of the imaging unit is provided with a switch element for reading out the electric charge generated in the first sensor unit, and the first sensor unit or It is preferable that the second sensor unit and the switch element are formed to overlap each other.

  Further, according to the present invention, as in the invention according to claim 4, the first sensor unit, the switch element, and the two sensor unit overlap each other on another support substrate. It may be formed as follows.

  Further, according to the present invention, as in the invention described in claim 5, the switch element, the first sensor unit, and the two sensor unit overlap each other on a separate support substrate. It may be formed as follows.

  According to a sixth aspect of the present invention, as in the sixth aspect of the present invention, at least one of the radiation irradiation start, the radiation irradiation end, and the radiation irradiation amount is detected based on the detection result by the second sensor unit. Detection means is further provided.

  According to the present invention, even when the radiation irradiation range is limited to an imaging region or a part of the imaging region, an effect is obtained that the radiation source can be controlled by detecting the radiation.

It is a block diagram which shows the structure of the radiation information system which concerns on 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 embodiment. It is a permeation | transmission perspective view which shows the internal structure of the electronic cassette concerning embodiment. It is sectional drawing which showed typically schematic structure of the imaging | photography part which concerns on 1st Embodiment. It is sectional drawing which showed the structure of the TFT substrate which concerns on 1st Embodiment. It is a top view which shows the structure of the TFT substrate which concerns on embodiment. (A) is a top view which shows schematic arrangement structure of TFT70 of the imaging | photography part which concerns on 1st Embodiment, the sensor part 72, and the sensor part 146, (B) is TFT70 of the imaging | photography part, and a sensor part 72 is a cross-sectional view showing a schematic arrangement configuration of 72 and sensor unit 146. It is a block diagram which shows the principal part structure of the electric system of the electronic cassette concerning embodiment. It is a block diagram which shows the principal part structure of the electrical system of the console which concerns on embodiment, and a radiation generator. It is a flowchart which shows the flow of a process of the imaging | photography control program which concerns on embodiment. It is sectional drawing which showed typically schematic structure of the imaging | photography part which concerns on 2nd Embodiment. It is sectional drawing which showed the structure of the TFT substrate which concerns on 2nd Embodiment. (A) is a top view which shows schematic arrangement structure of TFT70 of the imaging | photography part, sensor part 72, and sensor part 146 which concern on 2nd Embodiment, (B) is TFT70 of the imaging | photography part, and sensor part 72 is a cross-sectional view showing a schematic arrangement configuration of 72 and sensor unit 146. 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.

  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 32 that captures a radiographic image indicated by the radiation X transmitted through the imaging region of the person, a cradle 40 that charges a battery built in the electronic cassette 32, an electronic cassette 32, a radiation generator 34, and a cradle And a console 42 for controlling 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. 9) 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 hermetic structure.

  Inside the casing 54, an imaging unit 21 that captures a radiographic image is disposed at a position facing the irradiation surface 56 of the casing 54 irradiated with the radiation X.

  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 imaging unit 21 and the electronic circuit are operated by electric power supplied from a battery 96 </ b> A disposed in the case 31. In order to avoid various circuits housed in the case 31 from being damaged by the radiation X irradiation, it is desirable to arrange a lead plate or the like on the irradiation surface 56 side of the case 31. The electronic cassette 32 according to the present embodiment is a rectangular parallelepiped whose irradiation surface 56 has a rectangular shape, and a 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.

  Next, the configuration of the imaging unit 21 that captures radiographic images will be described.

  FIG. 4 is a cross-sectional view illustrating a schematic configuration of the imaging unit 21 according to the first embodiment.

  The imaging unit 21 according to the present embodiment includes a thin film transistor (TFT) 70, a storage capacitor 68, and a sensor unit 72 that generates charges when light is incident on an insulating substrate 64. The TFT active matrix substrate (hereinafter referred to as “TFT substrate”) 66 is formed.

  On one surface of the TFT substrate 66, a radiation detection unit 62 in which a sensor unit 146 to be described later is formed is disposed, and a scintillator 71 is attached on the radiation detection unit 62. In the present embodiment, the imaging unit 21 is arranged in the housing 54 so that the scintillator 71 side faces the irradiation surface 56, and the radiation X transmitted through the irradiation surface 56 passes through the scintillator 71 and the radiation detection unit 62. Then, the light enters the TFT substrate 66.

  As the scintillator 71, for example, CsI: Tl, GOS 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 provided so that the sensor portion 72 and the TFT 70 do not overlap each other, and an insulating film 65A for flattening the TFT substrate 66 is formed.

  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 this embodiment, the photoelectric conversion film 72C is configured to include amorphous silicon.

  FIG. 5 schematically shows the configuration of the TFT substrate 66 according to the present embodiment.

  In the TFT substrate 66, an electrode 67 and a gate electrode 70 </ b> A are formed on an insulating substrate 64. In the wiring layer in which the electrode 67 and the gate electrode 70A are formed, a gate wiring 76 (see FIG. 4) is formed together with the electrode 67 and the gate electrode 70A. The gate electrode 70A is connected to the gate wiring 76. The wiring layer in which the electrode 67 and the gate electrode 70A are formed (hereinafter, this wiring layer is also referred to as “first signal wiring layer”) uses Al or Cu, or a laminated film mainly composed of Al or Cu. Although formed, it is not limited to these.

  An insulating film 65B is formed on one surface on the first signal wiring layer. In the insulating film 65B, the portion located on the gate electrode 70A functions as a gate insulating film in the TFT 70. The insulating film 65B is made of, for example, SiNX, and is formed by, for example, CVD (Chemical Vapor Deposition) film formation.

  An active layer (channel layer) 70B made of amorphous silicon is formed on the insulating film 65B at a position corresponding to the gate electrode 70A.

  A source electrode 70C and a drain electrode 70D are formed in these upper layers. In the wiring layer in which the source electrode 70C and the drain electrode 70D are formed, the data wiring 78 (see FIG. 4) is formed together with the source electrode 70C and the drain electrode 70D, and the lower electrode of the sensor unit 72 is formed. 72B is formed. The source electrode 70C is connected to the data wiring 78 (see FIG. 4), and the drain electrode 70D is connected to the lower electrode 72B. The wiring layer in which the source electrode 70C, the drain electrode 70D, the data wiring 78, and the lower electrode 72B are formed (hereinafter, this wiring layer is also referred to as “second signal wiring layer”) is also Al or Cu, or Al or Cu. However, the present invention is not limited to this.

  On the second signal wiring layer, a photoelectric conversion film 72C made of amorphous silicon is formed at a position corresponding to the lower electrode 72B.

  An upper electrode 72A is formed on the photoelectric conversion film 72C. The wiring layer in which the upper electrode 72A is formed (hereinafter, this wiring layer is also referred to as “third signal wiring layer”) is also formed using Al or Cu, or a laminated film mainly composed of Al or Cu. However, it is not limited to these.

  In the TFT substrate 66 according to the present embodiment, the gate electrode 70A, the insulating film 65B, the source electrode 70C, the drain electrode 70D, and the active layer 70B constitute the TFT 70, and the electrode 67 and the lower electrode 72B constitute the storage capacitor 68. Is done.

  Then, an insulating film 65A is formed on almost the entire surface (substantially the entire region) of the region where the pixels of the insulating substrate 64 are provided so as to cover them. The step of the lower layer is flattened by the insulating film 65A, and the capacitance between the metals disposed in the upper layer and the lower layer of the insulating film 65A is kept low.

  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 in a matrix.

  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.

  On such a TFT substrate 66, as shown in FIG. 4, a radiation detector 62 is arranged.

  On the other hand, as shown in FIG. 4, the radiation detection unit 62 includes, for example, a wiring layer 142 and an insulating layer 144 in which a wiring 160 (FIG. 8) to be described later is patterned on one surface of a resinous support substrate 140. A plurality of sensor portions 146 are formed on the TFT substrate 66 so as to correspond to the respective pixels 74.

  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 148 is incident thereon. The photoelectric conversion film 147C absorbs light emitted from the scintillator 71 and generates electric charges according to the absorbed light. The photoelectric conversion film 147C may be formed using a material that generates charges when irradiated with light. For example, the photoelectric conversion film 147C can be formed using amorphous silicon, an organic photoelectric conversion material, or the like. A photoelectric conversion film containing an organic photoelectric conversion material is preferable to the MIS photodiode. 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. If the photoelectric conversion film 147C contains 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. Can be effectively suppressed noise generated by the absorption by the photoelectric conversion film 147C. In addition, the organic photoelectric conversion material can be formed into a film by a droplet discharge device (so-called inkjet device) that discharges droplets containing the organic photoelectric conversion material from the recording head, and is supported by using the droplet discharge device. By forming the sensor unit 146 on the substrate 140, the manufacturing cost of the radiation detection unit 62 can be reduced.

  In this embodiment mode, the photoelectric conversion film 147C is configured to include 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 (Ti) 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.

  7A is a plan view showing a schematic arrangement configuration of the sensor unit 72, the TFT 70, and the sensor unit 146 in each pixel 74 of the imaging unit 21 according to the present embodiment, and FIG. 1 is a cross-sectional view illustrating a schematic arrangement configuration of the sensor unit 72, the TFT 70, and the sensor unit 146 in each pixel 74 of the imaging unit 21. In the present embodiment, as shown in FIG. 7A, the sensor portion 72 and the sensor portion 146 are formed in substantially the same size in each pixel 74, but the size of the sensor portion 72 and the sensor portion 146 is the same. (The area of the light receiving surface) may be different. Since the sensor unit 72 is used for image acquisition, the sensor unit 72 is preferably highly sensitive. On the other hand, the sensor unit 146 is not necessarily required to have high sensitivity because it is only necessary to detect radiation. Therefore, it is preferable that the sensor unit 72 has a larger light receiving surface area than the sensor unit 146.

  In the present embodiment, the sensor portion 72 and the TFT 70 are provided on the TFT substrate 66 so as not to overlap each other for each pixel 74 as described above, and the sensor portion 146 is disposed so as to cover the upper portion of the TFT 70 portion. ing.

  FIG. 8 is a block diagram showing the main configuration of the electrical system of the electronic cassette 32 according to the present embodiment.

  As described above, the TFT substrate 66 has a large number of pixels 74 including the sensor unit 72, the storage capacitor 68, and the TFT 70 arranged in a matrix, and the sensor unit 72 is associated with the irradiation of the radiation X to the electronic cassette 32. The electric charges generated in (1) 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 on the TFT substrate 66 of the imaging unit 21.

  The individual gate lines 76 of the TFT substrate 66 are connected to the gate line driver 80, and the individual data lines 78 are connected to the signal processing unit 82. 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.

  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 image data is converted by an A / D converter.

  An image memory 90 is connected to the signal processing unit 82, and image 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, and image data obtained by imaging is sequentially stored in the image memory 90 every time a radiographic image is captured.

  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.

  On the other hand, in the radiation detection unit 62, a plurality of sensor units 146 are formed in a matrix corresponding to each pixel 74 of the TFT substrate 66 as described above. In addition, the radiation detection unit 62 is provided with a plurality of wirings 160.

  In the radiation detection unit 62 according to the present embodiment, a plurality of sensor units 146 are connected in parallel to the wiring 160. FIG. 8 shows an example in which four sensor units 146 of 2 rows × 2 columns are connected in parallel to one wiring 160 as sensor groups 180, but M rows × N columns (M, N is a natural number, and several tens to several hundreds of sensor units 146 are connected in parallel to one wiring 160 as a sensor group 180. By connecting a plurality of sensor units 146 in parallel to one wiring 160 in this way, the plurality of sensor units 146 connected in parallel to one wiring 160 function as one sensor, and thus sensitivity to radiation. Will improve. 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.

  In addition, 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, signal detection). The unit 162 and the like are operated by the electric power supplied from the power source 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. 8, illustration of wirings connecting the power supply unit 96 to various circuits and elements is omitted.

  FIG. 9 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. 9). .).

  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. In the case of fluoroscopic imaging, the photographer designates a lower radiation dose per unit time than in the case of still image shooting in order to suppress the exposure of the subject (for example, 1 in the case of still image shooting). / 10).

  Here, even if the TFT substrate 66 of the imaging unit 21 is not irradiated with X-rays, a charge is generated in the sensor unit 72 due to dark current or the like, and the charge is stored in the storage capacitor 68 of each pixel 74. .

  For this reason, in the electronic cassette 32 according to the present embodiment, when the radiation image is taken, the radiation detection unit 62 detects the radiation, and when the start of radiation irradiation is detected, the accumulation of each pixel 74 of the TFT substrate 66 is performed. Imaging is started after a reset operation for taking out and removing the electric charge accumulated in the capacitor 68 is performed.

  Further, in the imaging system 18 according to the present embodiment, during the imaging, the radiation detection unit 62 detects the radiation dose applied to the electronic cassette 32 and controls the irradiation with radiation from the radiation source 130 ( So-called AEC (automatic exposure control) is performed. Specifically, in the case of still image shooting, when the detected radiation dose reaches an allowable amount, radiation irradiation from the radiation source 130 is terminated and image reading is started from the TFT substrate 66. 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 by the radiation detection unit 62 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.

  By the way, in the electronic cassette 32 according to the present embodiment, as described above, when the radiation image is taken, the radiation detection unit 62 detects the radiation, and the reset operation is performed when the irradiation start is detected. After performing, imaging is started, and the radiation dose irradiated to the electronic cassette 32 is detected during imaging.

  FIG. 10 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 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.

  When each sensor unit 146 provided in the radiation detection unit 62 is irradiated with radiation, an electric charge is generated. The generated charges flow out as electric signals to the wiring 160, respectively.

  In the next step S12, the value of the digital data input from the signal detection unit 162 is compared with a predetermined threshold value for radiation detection, and detection of the start of radiation irradiation is performed depending on whether or not the threshold value is exceeded. If the value of the digital data is equal to or greater than the threshold value, the process proceeds to step S14 assuming that radiation irradiation has started. If the value of the digital data is less than the threshold value, the process returns to step S12. Transition to wait for the start of radiation irradiation.

  In the next step S14, the gate line driver 80 is controlled to output a control signal from the gate line driver 80 to turn on the TFT 70 to each gate wiring 76, and each TFT 70 connected to each gate wiring 76 is line by line. The charge is taken out by turning it on in order. As a result, the charges accumulated in the storage capacitor 68 of each pixel 74 sequentially flow out to each data wiring 78 as an electric signal, and the charges accumulated in the storage capacitor 68 of each pixel 74 are removed by dark current or the like. .

  In the next step S16, 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 S18, and in the case of a negative determination ( If fluoroscopic shooting is designated as the shooting mode), the process proceeds to step S30.

  In step S18, 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 the next step S20, the value of the digital data input from the signal detection unit 162 is corrected according to the sensitivity of the sensor unit 146, and the corrected value is accumulated for each sensor group 180. This cumulative value can be regarded as the radiation dose irradiated.

  In the next step S22, it is determined whether or not the cumulative value of any one of the sensor groups 180 has exceeded the allowable amount. If the determination is affirmative, the process proceeds to step S24. If the determination is negative, step S20 is performed. Migrate to

  In step S24, 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> 26, 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.

  In the TFT substrate 66, 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 in order 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 S28, 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 S30, an imaging cycle corresponding to the fluoroscopic frame rate is obtained.

  In the next step S <b> 32, the value of the digital data input from the signal detection unit 162 is corrected according to the sensitivity of the sensor unit 146, and the corrected value is accumulated for each sensor group 180.

  In the next step S34, it is determined whether or not the cumulative value of the digital data of any one of the sensor groups 180 has exceeded the allowable amount. If the determination is affirmative, the process proceeds to step S50, and the determination is negative. Proceeds to step S36.

  In step S36, 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 TFT substrate 66 was read last time. If the determination is affirmative, the process proceeds to step S38, and negative. When it becomes determination, it transfers to step S32.

  In the next step S38, 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 TFT substrate 66 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 S40, the image data stored in the image memory 90 is transmitted to the console 42. After the image data is transmitted, the process proceeds to step S32.

  On the other hand, in step S50, 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, the case where the fluoroscopic imaging is stopped when the cumulative value of any one of the sensor units 146 becomes an allowable amount during fluoroscopic imaging has been described. However, the console 42 has exceeded the allowable amount. This may be notified, 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.

  The cumulative value of the digital data values detected by each sensor unit 146 of the sensor group 180 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.

  As described above, according to the present embodiment, the scintillator 71 that generates light by irradiating the imaging region with radiation is provided, and the radiographic imaging sensor unit 72 and the radiation detection so as to overlap the scintillator 71. Since the plurality of pixels 74 formed so that the sensor unit 146 for use does not overlap is provided in a matrix, the sensor can be used even when the radiation irradiation range is limited to the imaging region or a part of the imaging region. The radiation source can be controlled by detecting radiation with the unit 146.

  In addition, according to the present embodiment, since the sensor unit 146 includes the organic photoelectric conversion material, radiation detection is performed by forming the sensor unit 146 on the support substrate 140 using a droplet discharge device. The manufacturing cost of the part 62 can be reduced.

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

  Since the configurations of the RIS 10, the imaging system 18, and the electronic cassette 32 according to the second embodiment are the same as those of the first embodiment (see FIGS. 1 to 3, 8, and 9), here. Description of is omitted.

  FIG. 11 is a cross-sectional view illustrating a schematic configuration of the imaging unit 21 according to the second embodiment.

  In the imaging unit 21 according to the present embodiment, for each pixel 74, an electrode 190 is formed on the TFT substrate 66 for electrical connection with the TFT 70, the storage capacitor 68, and the sensor unit 72. 72 and the sensor unit 146 are formed in parallel so as not to overlap each other.

  FIG. 12 schematically shows the configuration of the TFT substrate 66 according to the present embodiment.

  In the TFT substrate 66, the electrode 190 is formed on the surface on the side where the radiation detection unit 62 is arranged for each pixel 74, and the storage capacitor 68 for storing the electric charge moved to the electrode 190 and the storage capacitor 68. A TFT 70 is formed that converts the generated charges into an electric signal and outputs the electric signal.

  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 TFT substrate 66 according to the present embodiment, 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 less than 6) is preferable, and InGaZnO is particularly preferable. ₄ is more preferable.

  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, the amorphous oxide constituting the active layer 70B of the TFT 70 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.

  13A is a plan view showing a schematic arrangement configuration of the sensor unit 72, the TFT 70, and the sensor unit 146 in each pixel 74 of the imaging unit 21 according to the present embodiment, and FIG. 1 is a cross-sectional view illustrating a schematic arrangement configuration of the sensor unit 72, the TFT 70, and the sensor unit 146 in each pixel 74 of the imaging unit 21. Also in this embodiment, as shown in FIG. 13A, the sensor portion 72 and the sensor portion 146 are formed in substantially the same size in each pixel 74, but the sensor portion 72 and the sensor portion 146 have the same size. The size (area of the light receiving surface) may be different. Since the sensor unit 72 is used for image acquisition, the sensor unit 72 is preferably highly sensitive. On the other hand, the sensor unit 146 is not necessarily required to have high sensitivity because it is only necessary to detect radiation. Therefore, it is preferable that the sensor unit 72 has a larger light receiving surface area than the sensor unit 146.

  In the present embodiment, a TFT 70 is provided for each pixel 74 on the TFT substrate 66, a sensor unit 72 and a sensor unit 146 are provided on the radiation detection unit 62, and the sensor unit 146 covers the upper part of the TFT 70 part. Is arranged.

  The sensor part 72 and the sensor part 146 can reduce the manufacturing cost of the radiation detection part 62 by forming a film with a droplet discharge device (so-called inkjet device) using an organic photoelectric conversion material.

  As described above, according to the present embodiment, the sensor unit 72 and the sensor unit 146 are configured to include the organic photoelectric conversion material and are formed in the radiation detection unit 62, thereby reducing the sensor unit 72 and the sensor unit 146. Can be formed at a cost.

  Further, according to the present embodiment, since the sensor part 72 is not formed on the TFT substrate 66, the TFT substrate 66 can be easily manufactured.

  As mentioned above, although this invention was demonstrated using 1st and 2nd 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. 14, the end of radiation irradiation is performed by comparing the digital data value of each sensor unit 146 input from the signal detection unit 162 with a predetermined threshold value for detecting radiation. If the value of the digital data of each sensor unit 146 is accumulated, as shown at T1 in FIG. 15, an inflection point at which the increase amount of the accumulated value decreases greatly is detected. In such a case, it can be detected that the irradiation has ended.

  In the above-described one embodiment, the case where the sensor portion 72 and the sensor portion 146 are arranged so as not to overlap each pixel 74 as shown in FIG. 7A has been described, but the present invention is limited to this. It is not a thing. For example, the sensor unit 72 and the sensor unit 146 may partially overlap. That is, the sensor part 72 and the sensor part 146 should just be formed so that at least one part may not overlap.

  In each of the above embodiments, as shown in FIGS. 4 and 11, the imaging unit 21 is disposed in the housing 54 so that the scintillator 71 side faces the irradiation surface 56, and is transmitted through the irradiation surface 56. Although the case where the radiation X passes through the scintillator 71 and the radiation detection unit 62 and enters the TFT substrate 66 has been described, the present invention is not limited to this. For example, the imaging unit 21 may be arranged in the housing 54 so that the TFT substrate 66 side faces the irradiation surface 56, and the radiation X may enter the imaging unit 21 from the TFT substrate 66 side.

  In each of the above embodiments, as shown in FIGS. 4 and 11, the radiation detection unit 62 on one surface side of the TFT substrate 66 is provided, and the scintillator 71 is pasted on the radiation detection unit 62 to perform imaging. Although the case where the part 21 was comprised was demonstrated, this invention is not limited to this. For example, the imaging unit 21 may be configured by arranging the radiation detection unit 62 on one surface of the TFT substrate 66 and attaching the scintillator 71 to the other surface of the TFT substrate 66. In this case, the imaging unit 21 may be disposed in the housing 54 so that either the scintillator 71 side or the radiation detection unit 62 side faces the irradiation surface 56. The imaging unit 21 emits light more strongly on one surface side of the scintillator 71 (opposite side of the TFT substrate 66) when radiation is irradiated (surface irradiation) from the one surface side to which the scintillator 71 is attached. When radiation is irradiated (backside irradiation) from the other surface side where the detection unit 62 is provided, the radiation that has passed through the radiation detection unit 62 and the TFT substrate 66 is incident on the scintillator 71, and the TFT substrate 66 side of the scintillator 71 is more Emits strong light. 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.

Further, in each of the above embodiments, as shown in FIG. 8, a plurality of sensor units 146 are connected in parallel as sensor groups 180 to the respective wirings 160 of the radiation detection unit 62, and the signal detection unit 162 for each sensor group 180. Although the case where the values of the digital data input from are accumulated is described, the present invention is not limited to this. For example, the radiation detector 62
The wiring 160 individually connected to the sensor unit 146 is provided, and the electric signal of each wiring 160 is converted into digital data in the signal detection unit 162, and the value of the digital data of each sensor unit 162 constituting the sensor group 180 is accumulated. It is good also as what to do.

  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 X-rays, visible light, ultraviolet rays, infrared rays, gamma rays, particle rays, or the like.

  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 first embodiment (see FIG. 10) is also an example, and unnecessary steps may be deleted or new within the scope of the gist of the present invention. It goes without saying that steps can be added and the processing order can be changed.

21 Imaging unit 32 Electronic cassette 64 Insulating substrate (supporting substrate)
70 TFT (switch element)
71 Scintillator (light emitting layer)
72 Sensor part (first sensor part)
74 pixels 92 cassette control unit 140 support substrate 146 sensor unit (second sensor unit)

Claims (6)

  A light emitting layer that generates light when irradiated with radiation is provided in an imaging region for capturing a radiation image, and a first sensor unit for radiation image capturing and radiation detection that generate charges when irradiated with light, respectively. A radiation imaging apparatus comprising: an imaging unit provided in a matrix so that a plurality of pixels formed so that at least part of the second sensor unit does not overlap at least partially overlap the light emitting layer. The radiation imaging apparatus according to claim 1, wherein the second sensor unit includes an organic photoelectric conversion material. Each pixel of the imaging unit is provided with a switch element for reading out electric charges generated in the first sensor unit, and is formed so that the first sensor unit or the second sensor unit and the switch element overlap each other. The radiation imaging apparatus according to claim 1 or 2. The radiation imaging apparatus according to claim 3, wherein the first sensor unit, the switch element, and the two sensor unit are formed so that the second sensor unit and the switch element overlap each other on a separate support substrate. The radiation imaging apparatus according to claim 3, wherein the switch element, the first sensor unit, and the second sensor unit are formed so that the second sensor unit and the switch element overlap each other on a separate support substrate. The detector according to any one of claims 1 to 5, further comprising detection means for detecting at least one of radiation start, radiation end, and radiation dose based on a detection result by the second sensor unit. The radiation imaging apparatus according to the item.