JP2014068882A - Radiation image photographing control device, radiation moving image photographing system, defect determination method for radiation image photographing apparatus and radiation image photographing control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a defect of a pixel for detecting a radiation dose with good accuracy.SOLUTION: A defect of a pixel for detecting a radiation dose is determined on the basis of a defect occurrence status of a pixel for photographing a radiation image in the periphery of the pixel for detecting a radiation dose. To be concrete, when the pixel for photographing a radiation image in the periphery of the marked pixel for detecting a radiation dose is a defective pixel, the marked pixel for detecting a radiation dose is determined to be also a defective pixel. Thus, a defect or the like caused by a foreign matter on a vertical can be detected.

Description

  The present invention relates to a radiographic imaging control device, a radiographic imaging system, a defect determination method for a radiographic video imaging device, and a radiographic imaging control program.

  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 dose into digital data (electrical signals) In some cases, a radiation image capturing apparatus that captures a radiation image represented by the amount of irradiated radiation using this radiation detector has been put into practical use.

  Some of such radiographic imaging apparatuses are provided with a radiation irradiation amount detection pixel for monitoring radiation in order to control the start and stop of radiation irradiation.

  For example, in the technique described in Patent Document 1, radiation that is uniformly arranged in a predetermined radiation detection region and that is applied to a subject is detected, and an electrical image signal corresponding to the detected radiation is transmitted via a switching element. A plurality of image radiation detection elements to be output to the wiring and a plurality of image radiation detection elements are disposed adjacent to each other, and are disposed in the radiation detection region uniformly and in a predetermined repeating pattern to irradiate the subject. There has been proposed a radiation detection device including a plurality of monitoring radiation detection elements that detect the detected radiation and directly output a monitoring electrical signal corresponding to the detected radiation to a signal wiring.

  Similarly to the radiation detection element for imaging, in order to detect the radiation dose by outputting an electrical signal to the signal wiring via the switching element, or to start or stop radiation by providing another sensor Some have been proposed for detecting the radiation dose.

JP 2012-164745 A

  However, in the technique described in Patent Document 1, since signals detected by each pixel of a plurality of radiation dose detection pixels (monitoring radiation detection elements) for detecting the radiation dose flow to the same signal wiring, When a defect occurs in the radiation dose detection pixel, it may be difficult to detect the defective pixel.

  Further, as in the technique described in Patent Document 1, when the irradiation amount detection amount pixel (radiation monitor detection element) is smaller than the radiation image capturing pixel (image radiation detection element), the S / N ratio is reduced. It is difficult to identify defects from the viewpoint.

  Moreover, even when detecting the radiation dose using another sensor or the like, it is possible to detect a defect based on a signal in a state where no radiation is irradiated, It is impossible to detect a defect caused by a defect of a scintillator that converts radiation into visible light.

  The present invention has been made in consideration of the above-described facts, and an object of the present invention is to make it possible to accurately detect a defect in a radiation dose detection pixel.

  In order to achieve the above object, a radiographic imaging apparatus according to the present invention includes a plurality of radiographic image capturing pixels for capturing a radiographic image, a radiation irradiation amount detecting pixel for detecting a radiation irradiation amount, Determination means for determining a defect of the radiation dose detection pixel based on a defect occurrence state of the radiation image pixel around the radiation dose detection pixel.

  According to the radiographic image capturing apparatus of the present invention, the plurality of radiographic image capturing pixels are used to capture a radiographic image, and the radiation dose detection pixels are used to detect the radiation dose.

  Then, the determination unit determines the defect of the radiation dose detection pixel based on the defect occurrence state of the radiation image capturing pixel around the radiation dose detection pixel. For example, in the case of a defect due to a vertical foreign matter or the like, the radiation image capturing pixels around the radiation dose detection pixels are likely to be defective, and therefore can be determined as defects. As a result, defects due to vertical foreign matter or the like can be detected, so that it is possible to accurately detect defects in the radiation dose detection pixels.

  In addition, when one pixel is configured with the radiation imaging pixel and the radiation irradiation amount detection pixel as sub-pixels, the determination unit has a defect occurrence state of the radiation imaging pixel constituting one pixel. Based on the above, the defect of the radiation dose detection pixel in the same pixel may be determined. That is, when the radiation image capturing pixel in one pixel is defective, the radiation irradiation amount detection pixel in the same pixel is likely to be defective, and may be determined as a defect.

  In addition, the determination unit predicts a value of a pixel photographed by the radiation dose detection pixel from a value of the surrounding radiation image pixel when there is no defect in the surrounding radiation image pixel, The defect of the radiation dose detection pixel may be determined based on the measured value and the value of the radiation dose detection pixel.

  Further, in the case of further comprising a signal line to which the radiation image capturing pixel and the radiation dose detection pixel are respectively connected, the determination unit is connected to the same signal line as the radiation dose detection pixel. In addition, the defect of the radiation dose detection pixel may be determined based on the defect occurrence status of the radiation image pixel read before and after the radiation dose detection pixel.

  The radiation image capturing pixel includes a sensor unit that generates a charge corresponding to the irradiated radiation, and a switching element that reads the charge generated by the sensor unit and outputs the charge to a signal line. The detection pixel may include a sensor unit that generates a charge corresponding to the irradiated radiation and outputs the generated charge to the signal line.

  In addition, this invention is good also as a radiographic imaging system provided with the above-mentioned radiographic imaging apparatus and the radiation irradiation means to irradiate the said radiographic imaging apparatus through a subject.

  On the other hand, the defect determination method of the radiographic image capturing apparatus of the present invention includes a plurality of radiographic image capturing pixels for capturing a radiographic image and a radiation dose detection pixel for detecting the radiation dose. In the radiographic imaging device, an acquisition step of acquiring a defect occurrence state of the radiation image pixel around the radiation exposure amount detection pixel, and the radiation irradiation amount detection pixel based on an acquisition result of the acquisition step A determination step of determining a defect of

  According to the defect determination method of the radiographic image capturing apparatus of the present invention, the plurality of radiographic image capturing pixels of the radiographic image capturing apparatus are used for capturing a radiographic image, and the radiation dose detection pixel is irradiated with radiation. Used to detect quantity.

  In the acquisition step, the defect occurrence status of the radiation image pixels around the radiation dose detection pixels is acquired.

  In the determination step, the defect of the radiation dose detection pixel is determined based on the acquisition result of the acquisition step. For example, in the case of a defect due to a vertical foreign matter or the like, the radiation image capturing pixels around the radiation dose detection pixels are likely to be defective, and therefore can be determined as defects. As a result, defects due to vertical foreign matter or the like can be detected, so that it is possible to accurately detect defects in the radiation dose detection pixels.

  In addition, when the radiation imaging pixel and the radiation irradiation amount detection pixel are subpixels to form one pixel, the determination step includes a defect in the radiation imaging pixel constituting one pixel. You may make it determine the defect of the said radiation irradiation amount detection pixel in the same pixel based on the generating condition. That is, when the radiation image capturing pixel in one pixel is defective, the radiation irradiation amount detection pixel in the same pixel is likely to be defective, and may be determined as a defect.

  Further, the determination step predicts a value of a pixel photographed by the radiation dose detection pixel from a value of the surrounding radiation image pixel when there is no defect in the surrounding radiation image pixel, The defect of the radiation dose detection pixel may be determined based on the measured value and the value of the radiation dose detection pixel.

  Furthermore, when the radiographic image capturing apparatus further includes a signal line to which the radiographic image capturing pixel and the radiation irradiation amount detection pixel are respectively connected, the determination step includes the radiation irradiation amount detection pixel and The defect of the radiation dose detection pixel is determined based on the defect occurrence status of the radiation image pixel connected to the same signal line and read out before and after the radiation dose detection pixel. Also good.

  In addition, this invention is good also as a radiographic imaging program for functioning a computer as the said determination means in the above-mentioned radiographic imaging apparatus.

  As described above, the present invention has an excellent effect that it is possible to detect a defect of a radiation dose detection pixel with high accuracy.

It is a schematic block diagram which shows schematic structure of an example of the radiographic imaging system which concerns on this Embodiment. It is a block diagram which shows an example of the whole structure of the electronic cassette concerning this Embodiment. It is a top view which shows an example of a structure of the radiation detector concerning this Embodiment. It is line sectional drawing of an example of the radiation detector which concerns on this Embodiment. It is line sectional drawing of an example of the radiation detector which concerns on this Embodiment. It is a schematic block diagram which shows an example of schematic structure of the signal detection circuit of the radiographic imaging apparatus which concerns on this Embodiment. It is a functional block diagram which shows the structural example of the control part in the electronic cassette of this Embodiment. (A) is a diagram showing a plurality of radiation dose detection pixels on one line, and (B) is a diagram showing a case where the radiation image capturing pixels around the radiation dose detection pixels are defective pixels. is there. It is a flowchart which shows an example of the defective pixel detection process of the radiation irradiation amount detection pixel performed in a control part. It is a figure for demonstrating the defect determination method of the radiation irradiation amount detection pixel of a 1st modification. It is a flowchart which shows an example of the defective pixel detection process of the radiation irradiation amount detection pixel performed by the control part of a 1st modification. (A) is a figure which shows the pixel structure of a 2nd modification, (B) is a figure which shows the circuit structure of the pixel of a 2nd modification, (C) is a figure which shows the modification of a pixel structure. . It is a flowchart which shows an example of the defective pixel detection process of the radiation irradiation amount detection pixel performed by the control part of a 2nd modification.

  Hereinafter, an example of the present embodiment will be described with reference to the drawings.

  First, a schematic configuration of the entire radiographic image capturing system including the radiographic image processing apparatus of the present embodiment will be described. FIG. 1 shows a schematic configuration diagram of an overall configuration of an example of a radiographic imaging system according to the present exemplary embodiment. The radiographic image capturing system 10 of the present embodiment can capture still images in addition to radiographic images as moving images. Note that in this embodiment, a moving image refers to displaying still images one after another at a high speed and recognizing them as moving images. The still images are captured, converted into electric signals, transmitted, and transmitted. The process of replaying a still image is repeated at high speed. Therefore, so-called “frame advance”, in which the same area (part or all) is photographed a plurality of times within a predetermined time and continuously reproduced depending on the degree of “high speed”, is also included in the moving image. Shall. Moreover, the radiographic imaging system 10 of this Embodiment has the function in which the electronic cassette 20 itself detects a radiation irradiation start (imaging start) and a radiation irradiation stop (imaging end). .

  The radiographic imaging system 10 of the present exemplary embodiment is based on an instruction (imaging menu) input from an external system (for example, RIS: Radiology Information System) via the console 16 and a doctor or radiographer. It has a function of taking a radiographic image by an operation such as the above.

  The radiographic image capturing system 10 of the present embodiment has a function of causing a doctor, a radiographer, or the like to interpret a radiographic image by displaying the captured radiographic image on the display 50 of the console 16 or the radiographic image interpretation device 18. It is what you have.

  The radiographic imaging system 10 according to the present exemplary embodiment includes a radiation generation device 12, a radiographic image processing device 14, a console 16, a storage unit 17, a radiographic image interpretation device 18, and an electronic cassette 20.

  The radiation generator 12 includes a power supply 22, a radiation irradiation controller 23, and a high voltage generator 24. The radiation irradiation control unit 23 has a function of irradiating the imaging target region of the subject 30 on the imaging table 32 from the radiation irradiation source 25 based on the control of the radiation control unit 62 of the radiation image processing apparatus 14. ing. The radiation irradiation control unit 23 according to the present embodiment supplies the current supplied from the power supply 22 to the high voltage generator 24, supplies the high voltage generated by the high voltage generator 24 to the radiation irradiation source 25, and generates radiation. X is generated. The power source 22 may be either an AC power source or a DC power source. Moreover, the high voltage generator 24 may be any of a single-phase transformer system, a three-phase transformer system, an inverter system, and a capacitor system. In addition, FIG. 1 shows a stationary radiation generator 12, but the invention is not limited to this, and the radiation generator 12 may be of a mobile type.

  The radiation X transmitted through the subject 30 is applied to the electronic cassette 20 held by the holding unit 34 inside the imaging table 32. The electronic cassette 20 has a function of generating a charge corresponding to the dose of the radiation X transmitted through the subject 30, generating image information indicating a radiation image based on the generated charge amount, and outputting the image information. The electronic cassette 20 according to the present embodiment includes a radiation detector 26. In the present embodiment, “dose” refers to radiation intensity, for example, radiation applied at a predetermined tube voltage and a predetermined tube current per unit time.

  In the present embodiment, image information indicating a radiographic image output from the electronic cassette 20 is input to the console 16 via the radiographic image processing device 14. The console 16 according to the present embodiment uses the radiographing device 12 and the electronic cassette 20 using an imaging menu and various information acquired from an external system (RIS) or the like via wireless communication (LAN: Local Area Network) or the like. It has a function to perform control. In addition, the console 16 according to the present embodiment has a function of transmitting / receiving various information including image information of a radiographic image to / from the radiographic image processing apparatus 14 and a function of transmitting / receiving various information to / from the electronic cassette 20. have.

  The console 16 of the present embodiment is configured as a server computer, and includes a control unit 49, a display driver 48, a display 50, an operation input detection unit 52, an operation panel 54, an I / O unit 56, and an I / F unit 57. , And an I / F unit 58.

  The control unit 49 has a function of controlling the operation of the entire console 16 and includes a CPU, a ROM, a RAM, and an HDD. The CPU has a function of controlling the operation of the entire console 16, and various programs including a control program used by the CPU are stored in advance in the ROM. The RAM has a function of temporarily storing various data, and the HDD (hard disk drive) has a function of storing and holding various data.

  The display driver 48 has a function of controlling display of various information on the display 50. The display 50 according to the present embodiment has a function of displaying an imaging menu, a captured radiographic image, and the like. The operation input detection unit 52 has a function of detecting an operation state with respect to the operation panel 54. The operation panel 54 is used by a doctor, a radiographer, or the like to input operation instructions related to radiographic image capturing. In the present embodiment, the operation panel 54 includes, for example, a touch panel, a touch pen, a plurality of keys, a mouse, and the like. When configured as a touch panel, it may be configured the same as the display 50.

  The I / O unit 56 and the I / F unit 58 transmit and receive various types of information to and from the radiographic image processing apparatus 14 and the radiation generation apparatus 24 through wireless communication, and also perform image information with the electronic cassette 20. And the like. The I / F unit 57 has a function of transmitting / receiving various types of information to / from the RIS.

  The control unit 49, the display driver 48, the operation input detection unit 52, the I / F unit 58, and the I / O unit 56 are connected so that information can be exchanged with each other via a bus 59 such as a system bus or a control bus. Has been. Therefore, the control unit 49 controls the display of various information on the display 50 via the display driver 48 and controls the transmission / reception of various information with the radiation generator 12 and the electronic cassette 20 via the I / F unit 58. Can be performed respectively.

  The radiographic image processing apparatus 14 according to the present embodiment has a function of controlling the radiation generating apparatus 12 and the electronic cassette 20 based on an instruction from the console 16 and also stores the radiographic image received from the electronic cassette 20 into the storage unit 17. And the function of controlling the display on the display 50 of the console 16 and the display on the radiographic image interpretation device 18.

  The radiographic image processing apparatus 14 according to the present embodiment includes a system control unit 60, a radiation control unit 62, a panel control unit 64, an image processing control unit 66, and an I / F unit 68.

  The system control unit 60 has a function of controlling the entire radiographic image processing apparatus 14 and a function of controlling the radiographic image capturing system 10. The system control unit 60 includes a CPU, ROM, RAM, and HDD. The CPU has a function of controlling operations of the entire radiographic image processing apparatus 14 and the radiographic imaging system 10, and various programs including a control program used by the CPU are stored in advance in the ROM. The RAM has a function of temporarily storing various data, and the HDD has a function of storing and holding various data. The radiation control unit 62 has a function of controlling the radiation irradiation control unit 23 of the radiation generator 12 based on an instruction from the console 16 or the like. The panel control unit 64 has a function of controlling the electronic cassette 20 based on an instruction from the console 16 or the like. The image processing control unit 66 has a function of performing various image processing on the radiation image.

  The system control unit 60, the radiation control unit 62, the panel control unit 64, and the image processing control unit 66 are connected to each other via a bus 69 such as a system bus or a control bus so that information can be exchanged.

  The storage unit 17 of the present embodiment has a function of storing a captured radiographic image and information related to the radiographic image. An example of the storage unit 17 is an HDD.

  The radiographic image interpretation device 18 according to the present embodiment is a device having a function for a radiographer to interpret a captured radiographic image, and is not particularly limited, and examples thereof include a so-called radiogram interpretation viewer and console. The radiographic image interpretation apparatus 18 of this embodiment is configured as a personal computer, and, like the console 16 and the radiographic image processing apparatus 14, a CPU, ROM, RAM, HDD, display driver, display 40, and operation input detection. Unit, operation panel 42, I / O unit, and I / F unit. In FIG. 1, only the display 40 and the operation panel 42 are shown, and other descriptions are omitted in order to avoid complicated description.

  Next, a schematic configuration of the electronic cassette 20 according to the present embodiment will be described. In FIG. 2, the schematic block diagram of an example of the electronic cassette 20 of this Embodiment is shown. In the present embodiment, a case will be described in which the present invention is applied to an indirect conversion radiation detector 26 that once converts radiation such as X-rays into light and converts the converted light into electric charges. In the present embodiment, the electronic cassette 20 includes an indirect conversion type radiation detector 26. In FIG. 2, description of a scintillator that converts radiation into light is omitted.

  The electronic cassette 20 according to the present embodiment detects synchronization of radiographic image capturing operations, such as detecting the start of radiation and starting radiographic imaging when radiation X irradiation to the radiation detector 26 is started. Perform control processing. In addition, the electronic cassette 20 detects an irradiation amount of the radiation X to the radiation detector 26 and terminates the capturing of the radiation image based on the accumulated irradiation amount, for example, AEC (Automatic Exposure Control) for controlling the capturing operation of the radiation image. Perform control processing.

  The radiation detector 26 includes a sensor unit 103 that receives light to generate electric charge, accumulates the generated electric charge, and a TFT switch 74 that is a switching element for reading out the electric charge accumulated in the sensor unit 103. A plurality of pixels 100 constituted by the above are arranged in a matrix. In the present embodiment, the sensor unit 103 generates electric charges when irradiated with light converted by the scintillator.

  A plurality of pixels 100 are arranged in a matrix in one direction (gate wiring direction in FIG. 2) and in a direction intersecting with the gate wiring direction (signal wiring direction in FIG. 2). In FIG. 2, the arrangement of the pixels 100 is shown in a simplified manner. For example, 1024 × 1024 pixels 100 are arranged in the gate wiring direction and the signal wiring direction.

  In the present embodiment, among the plurality of pixels 100, a radiation image capturing pixel 100A and a radiation irradiation amount detection pixel 100B are determined in advance. In FIG. 2, the radiation dose detection pixel 100B is surrounded by a broken line. The radiation image capturing pixel 100A is used to detect the radiation X and generate an image indicated by the radiation X. The radiation irradiation amount detection pixel 100B is a pixel used for detection of the radiation X for detecting the start or stop of irradiation of the radiation X, and is a charge accumulation period regardless of whether the TFT switch 74 is on or off. However, it is a pixel that outputs electric charge, and in this embodiment, the source and drain of the TFT switch 74 are short-circuited.

  The radiation detector 26 has a plurality of gate wirings 101 for turning on / off the TFT switch 74 and a plurality for reading out the charges accumulated in the sensor unit 103 on the substrate 71 (see FIG. 4). The signal wiring 73 is provided so as to cross each other. In this embodiment, one signal wiring 73 is provided for each pixel column in one direction, and one gate wiring 101 is provided for each pixel column in the cross direction. For example, the pixel 100 is arranged in the gate wiring direction. When 1024 × 1024 are arranged in the signal wiring direction, 1024 signal wirings 73 and 1024 gate wirings 101 are provided.

  Further, the radiation detector 26 is provided with a common electrode wiring 95 in parallel with each signal wiring 73. The common electrode wiring 95 has one end and the other end connected in parallel, and one end connected to a bias power supply 110 that supplies a predetermined bias voltage. The sensor unit 103 is connected to the common electrode wiring 95, and a bias voltage is applied via the common electrode wiring 95.

  A scan signal for switching each TFT switch 74 flows through the gate wiring 101. In this way, each TFT switch 74 is switched by the scan signal flowing through each gate wiring 101.

  An electric signal corresponding to the electric charge accumulated in each pixel 100 flows through the signal wiring 73 in accordance with the switching state of the TFT switch 74 of each pixel 100. More specifically, an electric signal corresponding to the amount of charge accumulated by turning on any TFT switch 74 of the pixel 100 connected to the signal wiring 73 flows through each signal wiring 73.

  Each signal wiring 73 is connected to a signal detection circuit 105 that detects an electrical signal flowing out to each signal wiring 73. Each gate line 101 is connected to a scan signal control circuit 104 that outputs a scan signal for turning on / off the TFT switch 74 to each gate line 101. In FIG. 2, the signal detection circuit 105 and the scan signal control circuit 104 are shown in a simplified form. However, for example, a plurality of signal detection circuits 105 and a plurality of scan signal control circuits 104 are provided (for example, 256). The signal wiring 73 or the gate wiring 101 is connected every time. For example, when 1024 signal wirings 73 and 1024 gate wirings 101 are provided, four scan signal control circuits 104 are provided, 256 gate wirings 101 are connected, and four signal detection circuits 105 are provided 256. The signal wiring 73 is connected one by one.

  The signal detection circuit 105 incorporates an amplification circuit 120 (see FIG. 6) for amplifying an input electric signal for each signal wiring 73. In the signal detection circuit 105, an electric signal input from each signal wiring 73 is amplified by an amplifier circuit and converted into a digital signal by an ADC (analog / digital converter) (details will be described later).

  The signal detection circuit 105 and the scan signal control circuit 104 are subjected to predetermined processing such as noise removal on the digital signal converted by the signal detection circuit 105, and the signal detection circuit 105 is provided with a signal detection timing. A control unit 106 that outputs a control signal indicating the timing of outputting the scan signal is connected to the scan signal control circuit 104.

  The control unit 106 according to the present embodiment is configured by a microcomputer, and includes a nonvolatile storage unit including a CPU (Central Processing Unit), a ROM and a RAM, a flash memory, and the like. The control unit 106 performs control for radiographic imaging by executing a program stored in the ROM by the CPU. Further, the control unit 106 performs a process (interpolation process) for interpolating the image data of each radiation irradiation amount detection pixel 100B on the image data on which the predetermined process has been performed, so that the irradiated radiation X is obtained. Generate the image shown. That is, the control unit 106 generates an image indicated by the irradiated radiation X by interpolating the image data of each radiation irradiation amount detection pixel 100B based on the image data subjected to the predetermined processing.

  3 is a plan view showing the structure of the radiation detector 26 of the indirect conversion type according to the present embodiment, and FIG. 4 is a cross-sectional view taken along line AA of the radiographic image capturing pixel 100A of FIG. FIG. 5 is a sectional view taken along line BB of the radiation dose detection pixel 100B of FIG. As shown in FIG. 4, the pixel 100A of the radiation detector 26 includes a gate wiring 101 (see FIG. 3) and a gate electrode 72 formed on an insulating substrate 71 made of non-alkali glass or the like. 101 and the gate electrode 72 are connected (see FIG. 3). The wiring layer in which the gate wiring 101 and the gate electrode 72 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 85 is formed on one surface of the first signal wiring layer, and a portion located on the gate electrode 72 functions as a gate insulating film in the TFT switch 74. The insulating film 85 is made of, for example, SiN _X or the like, and is formed by, for example, CVD (Chemical Vapor Deposition) film formation.

  A semiconductor active layer 78 is formed in an island shape on the gate electrode 72 on the insulating film 85. The semiconductor active layer 78 is a channel portion of the TFT switch 74 and is made of, for example, an amorphous silicon film.

  On these upper layers, a source electrode 79 and a drain electrode 83 are formed. In the wiring layer in which the source electrode 79 and the drain electrode 83 are formed, a signal wiring 73 is formed together with the source electrode 79 and the drain electrode 83. The source electrode 79 is connected to the signal wiring 73 (see FIG. 3). The wiring layer in which the source electrode 79, the drain electrode 83, and the signal wiring 73 are formed (hereinafter, this wiring layer is also referred to as a “second signal wiring layer”) is a laminated layer mainly composed of Al or Cu or Al or Cu. The film is formed using, but is not limited to these. Between the source electrode 79 and the drain electrode 83 and the semiconductor active layer 78, an impurity doped semiconductor layer (not shown) made of impurity doped amorphous silicon or the like is formed. These constitute a switching TFT switch 74. In the TFT switch 74, the source electrode 79 and the drain electrode 83 are reversed depending on the polarity of charges collected and accumulated by the lower electrode 81 described later.

In order to protect the TFT switch 74 and the signal wiring 73, a TFT protective film layer 98 is provided on almost the entire area (substantially the entire area) where the pixels 100 are provided on the substrate 71 so as to cover these second signal wiring layers. Is formed. The TFT protective film layer 98 is made of, for example, SiN _X or the like, and is formed by, for example, CVD film formation.

  A coating type interlayer insulating film 82 is formed on the TFT protective film layer 98. This interlayer insulating film 82 is a photosensitive organic material having a low dielectric constant (relative dielectric constant εr = 2 to 4) (for example, a positive photosensitive acrylic resin: a base made of a copolymer of methacrylic acid and glycidyl methacrylate). It is formed with a film thickness of 1 to 4 μm by a material obtained by mixing a polymer with a naphthoquinonediazide positive photosensitive agent.

  In the radiation detector 26 of the present embodiment, the capacitance between the metals arranged in the upper layer and the lower layer of the interlayer insulating film 82 is suppressed by the interlayer insulating film 82. In general, such a material also has a function as a flattening film, and has an effect of flattening a lower step. In the radiation detector 26 of the present embodiment, a contact hole 87 is formed at a position facing the drain electrode 83 of the interlayer insulating film 82 and the TFT protective film layer 98.

  A lower electrode 81 of the sensor unit 103 is formed on the interlayer insulating film 82 so as to cover the pixel region while filling the contact hole 87, and the lower electrode 81 is connected to the drain electrode 83 of the TFT switch 74. ing. If the semiconductor layer 91 described later is as thick as about 1 μm, the material of the lower electrode 81 is not limited as long as it has conductivity. For this reason, there is no problem if it is formed using an Al-based material, a conductive metal such as ITO.

  On the other hand, when the thickness of the semiconductor layer 91 is thin (around 0.2 to 0.5 μm), light is not sufficiently absorbed by the semiconductor layer 91, so that an increase in leakage current due to light irradiation to the TFT switch 74 is prevented. An alloy mainly composed of a light-shielding metal or a laminated film is preferable.

  A semiconductor layer 91 that functions as a photodiode is formed on the lower electrode 81. In the present embodiment, a PIN structure photodiode in which an n + layer, an i layer, and a p + layer (n + amorphous silicon, amorphous silicon, p + amorphous silicon) are stacked is employed as the semiconductor layer 91, and the n + layer 21A is formed from the lower layer. , I layer 21B and p + layer 21C are sequentially stacked. The i layer 21 </ b> B generates charges (a pair of free electrons and free holes) when irradiated with light. The n + layer 21A and the p + layer 21C function as contact layers, and electrically connect the lower electrode 81 and an upper electrode 92 described later to the i layer 21B.

  An upper electrode 92 is individually formed on each semiconductor layer 91. For the upper electrode 92, for example, a material having high light transmittance such as ITO or IZO (zinc oxide indium) is used. In the radiation detector 26 according to the present exemplary embodiment, the sensor unit 103 includes the upper electrode 92, the semiconductor layer 91, and the lower electrode 81.

  On the interlayer insulating film 82, the semiconductor layer 91, and the upper electrode 92, a coating type interlayer insulating film 93 is formed so as to have a part of the opening 97 </ b> A corresponding to the upper electrode 92 and cover each semiconductor layer 91. Yes.

  On the interlayer insulating film 93, the common electrode wiring 95 is formed of Al or Cu, or an alloy or laminated film mainly composed of Al or Cu. The common electrode wiring 95 has a contact pad 97 formed in the vicinity of the opening 97 </ b> A and is electrically connected to the upper electrode 92 through the opening 97 </ b> A of the interlayer insulating film 93.

  On the other hand, as shown in FIG. 5, in the radiation dose detection pixel 100B of the radiation detector 26, the TFT switch 74 is formed so that the source electrode 79 and the drain electrode 83 are in contact with each other. That is, in the pixel 100B, the source and drain of the TFT switch 74 are short-circuited. As a result, in the pixel 100 </ b> B, the charges collected by the lower electrode 81 flow out to the signal wiring 73 regardless of the switching state of the TFT switch 74.

In the radiation detector 26 formed in this way, a protective film is formed of an insulating material having a low light absorption as required, and radiation conversion is performed using an adhesive resin having a low light absorption on the surface. A layer scintillator is affixed. Alternatively, the scintillator is formed by a vacuum deposition method. As the scintillator, a scintillator that generates fluorescence having a relatively wide wavelength region that can generate light in an absorbable wavelength region is desirable. Examples of such a scintillator include CsI: Na, CaWO ₄ , YTaO ₄ : Nb, BaFX: Eu (X is Br or Cl), LaOBr: Tm, and GOS. Specifically, when imaging using X-rays as the radiation X, those containing cesium iodide (CsI) are preferable, and CsI: Tl (thallium is added) having an emission spectrum at 420 nm to 700 nm at the time of X-ray irradiation. It is particularly preferable to use cesium iodide) or CsI: Na. Note that the emission peak wavelength in the visible light region of CsI: Tl is 565 nm. Moreover, when using the scintillator containing CsI as a scintillator, it is preferable to use what was formed as a strip-like columnar crystal structure by the vacuum evaporation method.

  As shown in FIG. 4, the radiation detector 26 is irradiated with radiation X from the side on which the semiconductor layer 91 is formed, and reads a radiation image with a TFT substrate provided on the back side of the incident surface of the radiation X. In the case of a so-called back side scanning method (PSS (Pentation Side Sampling) method), light is emitted more strongly on the upper surface side of the scintillator provided on the semiconductor layer 91 in the figure. On the other hand, radiation X is irradiated from the TFT substrate side, and a radiation image is read by a TFT substrate provided on the surface side of the incident surface of the radiation X, which is a so-called surface reading method (ISS (Irradiation Side Sampling) method). In this case, the radiation X transmitted through the TFT substrate enters the scintillator, and the TFT substrate side of the scintillator emits light more strongly. Electric charges are generated in the sensor portion 103 of each pixel 100 provided on the TFT substrate by light generated by the scintillator. For this reason, the radiation detector 26 has a higher resolution of the radiographic image obtained by photographing because the light emission position of the scintillator with respect to the TFT substrate is closer when the front surface reading method is used than when the rear surface reading method is used.

  The radiation detector 26 is not limited to those shown in FIGS. 3 to 5 and can be variously modified. For example, in the case of the back side scanning method, since there is a low possibility that the radiation X will reach, in place of the above, other imaging elements such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor having low resistance to the radiation X You may combine with TFT. Further, it may be replaced with a charge-coupled device (CCD) image sensor that transfers charges while shifting them with a shift pulse corresponding to a TFT scan signal.

  For example, a flexible substrate may be used. In order to improve the transmittance | permeability of the radiation X, it is preferable to apply what uses the ultra-thin glass by the float method developed recently as a base material as a flexible substrate. As for the ultra-thin glass that can be applied at this time, for example, “Asahi Glass Co., Ltd.,“ Successfully developed the world's thinnest 0.1 mm-thick ultra-thin glass by the float process ”, Aug. 20 search], Internet <URL: http://www.agc.com/news/2011/0516.pdf> ”.

  Next, a schematic configuration of the signal detection circuit 105 of the present embodiment will be described. FIG. 6 is a schematic configuration diagram of an example of the signal detection circuit 105 according to the present embodiment. The signal detection circuit 105 according to the present embodiment includes an amplification circuit 120 and an ADC (analog / digital converter) 124. Although not shown in FIG. 6, the amplifier circuit 120 is provided for each signal wiring 73. In other words, the signal detection circuit 105 includes a plurality of amplifier circuits 120 that are the same number as the number of signal wirings 73 of the radiation detector 26.

  The amplifier circuit 120 includes a charge amplifier circuit, and includes an amplifier 122 such as an operational amplifier, a capacitor C connected in parallel to the amplifier 122, and a charge reset switch SW1 connected in parallel to the amplifier 122. It is prepared for.

  In the amplifying circuit 120, the charge (electric signal) is read by the TFT switch 74 of the pixel 100 with the charge reset switch SW1 turned off, and the charge read by the TFT switch 74 is accumulated in the capacitor C. The voltage value output from the amplifier 122 increases in accordance with the amount of stored charge.

  The control unit 106 applies a charge reset signal to the charge reset switch SW1 to control on / off of the charge reset switch SW1. When the charge reset switch SW1 is turned on, the input side and output side of the amplifier 122 are short-circuited, and the capacitor C is discharged.

  The ADC 124 has a function of converting an electrical signal that is an analog signal input from the amplifier circuit 120 into a digital signal when the S / H (sample hold) switch SW is in an ON state. The ADC 124 sequentially outputs electrical signals (charge information) converted into digital signals to the control unit 106.

  Note that the ADC 124 of this embodiment receives the electrical signals output from all the amplifier circuits 120 provided in the signal detection circuit 105. That is, the signal detection circuit 105 of this embodiment includes one ADC 124 regardless of the number of amplifier circuits 120 (signal wiring 73).

  In the present embodiment, it is configured to perform detection related to irradiation of the radiation X without requiring a control signal from the outside (for example, the radiation image processing apparatus 14). In the present embodiment, an electrical signal (charge information) of the signal wiring 73 (in the case of FIG. 2, at least one of D2 and D3, for example, D2) connected to the radiation dose detection pixel 100B is supplied to the signal detection circuit 105. The signal is detected by the amplifier circuit 120 and converted into a digital signal. In the present embodiment, the control unit 106 is configured to acquire the digital signal converted by the signal detection circuit 105 and detect the start and stop of irradiation of the radiation X based on the set parameters. ing. In this embodiment, “detection” of an electric signal indicates sampling of the electric signal.

  FIG. 7 is a functional block diagram showing a configuration example of the control unit 106 in the electronic cassette 20 of the present embodiment.

  The control unit 106 includes a CPU 160, a ROM 161, a RAM 162, and an input / output unit 163, and each is connected to a bus such as a system bus or a data bus.

  The CPU 160 has a function of controlling the operation of the entire electronic cassette 20, and various programs used by the CPU 160 are stored in the ROM 161 in advance. The RAM 162 has a function of temporarily storing various data, and has a function of developing and storing programs and the like stored in the ROM 161.

  A hard disk (HDD) 165, an I / F unit 166, a scan signal control circuit 104, and a signal detection circuit 105 are connected to the input / output unit 163.

  The HDD has a function of storing and holding various data, and the I / F unit 166 has a radiography or wired communication with the radiographic image processing device 14, the console 16, or the like to obtain an imaging menu or radiographic image. It has a function of transmitting and receiving various information including image information.

  The control unit 106 according to the present embodiment activates various programs, controls the scan control circuit 104 and the signal detection circuit 105, and performs imaging by the radiation detector 26. Further, the control unit 106 has a function of acquiring the electrical signal (charge information) output from the radiation dose detection pixel 100B and detecting the start and stop of radiation irradiation.

  Incidentally, in the electronic cassette 20 configured as described above, it may be difficult to detect a defect in the radiation dose detection pixel 100B.

  For example, as in the present embodiment, in the radiation dose detection pixel 100B in which the source and drain of the TFT switch 74 are short-circuited, as shown in FIG. 8A, one line (one signal wiring 73) is provided. Since there are a plurality (two in FIG. 8A) of radiation dose detection pixels 100B and the values of the radiation dose detection pixels 100B of all the lines are added and output, which pixel is defective. I can not identify. Further, when the output of the radiation dose detection pixel 100B is smaller than the output of the radiation image capturing pixel 100A, it is difficult to determine the defect from the viewpoint of the S / N ratio.

  In addition, even when a separate sensor is used, a defect that occurs due to other factors (for example, a foreign object vertically above the sensor) can be detected even if a sensor defect can be detected from the offset output of the sensor. Can not do it.

  Therefore, in the present embodiment, the control unit 106 determines the defect of the radiation dose detection pixel 100B based on the defect occurrence status of the radiation image capturing pixel 100A around the radiation dose detection pixel 100B. It has become.

  Specifically, as shown in FIG. 8B, when the radiation image capturing pixel 100A around the focused radiation dose detection pixel 100B is a defective pixel, the focused radiation dose detection pixel 100B. Are also determined as defective pixels. As a result, it is possible to detect a defect or the like due to the presence of a foreign object vertically.

  In the example of FIG. 8B, when all (eight) radiation image capturing pixels around the radiation dose detection pixel 100B are defective, the target radiation dose detection pixel 100B is also defective. An example of determination will be shown. When a predetermined number of surrounding radiographic image capturing pixels 100A are defective but not all of the peripheral radiographic image capturing pixels 100A, the radiation dose detection pixel 100B is determined to be defective. You may make it do.

  Next, an example of processing performed by the control unit 106 of the electronic cassette 20 according to the present embodiment will be described. FIG. 9 is a flowchart illustrating an example of the defective pixel detection process for the radiation dose detection pixels performed by the control unit 106.

  In step S100, defect detection of the radiographic image capturing pixel 100A is performed, and the process proceeds to step S102. The defect detection of the radiation image capturing pixel 100A is performed by, for example, reading the value of the radiation image capturing pixel 100A in a state in which no radiation is irradiated and determining a pixel having a value different from other pixels by a predetermined value or more as a defective pixel. Alternatively, the value of the radiographic image capturing pixel 100A when radiation is irradiated under a predetermined imaging condition is read, and a value different from a reference value for the imaging condition by a predetermined threshold or more is output. The pixel may be determined as a defective pixel, or the defective pixel may be determined by applying another method.

  In step S102, the defect result of the radiographic imaging pixels around the target radiation dose detection pixel 100B is acquired, and the process proceeds to step S104.

  In step S104, it is determined whether the target radiation irradiation amount detection pixel 100B is a defective pixel. This determination may determine whether or not all surrounding radiographic image capturing pixels 100A are defective pixels, or determine whether or not a predetermined number or more of the surrounding radiographic image capturing pixels 100A are defective pixels. You may make it do. If the determination is affirmative, the process proceeds to step S106, and if the determination is negative, the process proceeds to step S108.

  In step S106, the target radiation irradiation amount detection pixel 100B is set as a defective pixel, and the process proceeds to step S108. That is, in the present embodiment, the surrounding radiation image capturing pixel 100A is a defective pixel, and the target radiation irradiation amount detection pixel 100B is also likely to be defective, so that it is determined as a defective pixel. It becomes possible to detect defective pixels due to foreign matter or the like on the vertical direction of the vessel 26. Although it may not actually be a defective pixel, the reliability of post-processing (for example, post-processing such as stopping irradiation when radiation reaches a predetermined amount) can be improved.

  In step S108, it is determined whether or not the defect determination has been completed for all the radiation dose detection pixels 100B. If the determination is negative, the process proceeds to step S110. The defective pixel detection process for the detection pixel is terminated.

  In step S110, the target radiation irradiation amount detection pixel is changed, the process returns to step S102, and the above-described processing is repeated.

  Thus, in the present embodiment, by determining the defect of the radiation dose detection pixel 100B based on the defect occurrence status of the radiation image capturing pixel 100A around the radiation dose detection pixel 100B, the vertical It is possible to detect a defective pixel even when there is a foreign substance on the top or when the values of a plurality of radiation dose detection pixels 100B are added to one line.

  Note that the configuration and method for detecting the start and stop of radiation X by the electronic cassette 20 itself are not limited to the present embodiment. For example, in the above description, the pixel including the TFT switch 74 in which the source and the drain are short-circuited has been described as the radiation dose detection pixel 100B, but is not limited thereto. For example, a connection wiring may be formed in the middle of the drain electrode 83 and connected to the signal wiring 73. Also in this case, the source and drain of the TFT switch 74 are substantially short-circuited. Further, when the source and drain of the TFT switch 74 are short-circuited, the gate electrode 72 may be formed away from the gate wiring 101. Further, for example, in the radiation dose detection pixel 100 </ b> B, by connecting the sensor unit 103 and the signal wiring 73 via the connection wiring 82 and the contact hole 87, the drain electrode 83 and the contact hole 87 are electrically connected. It may be cut.

  In the present embodiment, the case where a pixel with the TFT switch 74 short-circuited is used as the radiation dose detection pixel 100B. However, the radiation dose detection pixel 100B is not particularly limited. For example, as a radiation image capturing pixel 100A, a pixel in which the TFT switch 74 is not short-circuited may be used as the radiation dose detection pixel 100B. In this case, the control of the TFT switch 74 of the pixel 100B is controlled independently of the control of the TFT switch 74 of the pixel 100A. In this case, as the pixel 100B, the predetermined pixel 100 of the radiation detector 26 may be used, or a pixel different from the pixel 100 in the radiation detector 26 may be provided.

  Furthermore, when a defective pixel of the radiation irradiation amount detection pixel 100B is detected by the above process (the process according to the flowchart of FIG. 9), an electron is detected according to the number of defects of the defective pixel and the amount of deviation of the output value of the defective pixel. The cassette 20 may not be used, may be interpolated using the output value of the adjacent or nearby radiation dose detection pixel, or used only when calculating the region of interest. Alternatively, the dose (radiation dose) may be calculated by excluding the detected defective line or block. Further, in the case of the radiation dose detection pixel 100B having the same configuration as the radiation image capturing pixel 100A, the pixel arrangement of the radiation dose detection pixel 100B may be changed and used.

  Next, a first modification example regarding defect determination of the radiation dose detection pixel 100B will be described. FIG. 11 is a diagram for explaining a defect determination method for a radiation dose detection pixel according to a first modification.

  In the above embodiment, the defect occurrence state of the surrounding eight radiation image capturing pixels 100A adjacent to the radiation irradiation amount detection pixel 100B is used as the periphery of the radiation irradiation amount detection pixel 100B. In the modification, as shown in FIG. 10, normal radiation image capturing pixels 100 </ b> A (hatched above and below the hatched pixels in FIG. 10) that are read out in the same line and before and after the radiation irradiation amount detection pixels 100 </ b> B. Based on the value of the (pixel), the defect of the radiation dose detection pixel 100B is determined.

  In the first modification, the value of the radiation dose detection pixel 100B is predicted from the value of the normal radiation image capturing pixel 100A read before and after the target radiation dose detection pixel 100B, and the prediction result and the actual The value of the radiation dose detection pixel 100B is compared. As a result, even if a plurality of pixels are added, if the predicted value exceeds a predetermined threshold value or more, it can be determined that the pixel is a defective pixel, so that a defect can be determined.

  In the first modification, the radiation image capturing pixels 100A on the same line are used, but they may not be on the same line. Further, when predicting the value of the radiation dose detection pixel, if there is a difference in reading gain of the radiation image capturing pixel, it is necessary to consider the difference in gain.

  In the first modification, the defect of the radiation dose detection pixel 100B is determined based on the same line of the radiation dose detection pixel 100B and the value of the normal radiation image capturing pixel 100A read before and after. However, as in the above-described embodiment, the defect of the radiation dose detection pixel 100B is determined based on the defect occurrence state of the radiation image capturing pixel 100A read before and after the same line of the radiation dose detection pixel 100B. You may make it determine. For example, when the radiation image capturing pixels 100A read before and after the same line of the radiation dose detection pixel 100B are both defective pixels, it is determined that the radiation dose detection pixel 100B is also defective, When one of the radiation image capturing pixels 100A read before and after the same line of the irradiation amount detection pixel 100B is defective, the radiation irradiation amount detection pixel 100B may be determined to be defective.

  Here, an example of processing performed by the control unit 106 of the electronic cassette 20 in the first modification will be described.

  FIG. 11 is a flowchart illustrating an example of a defective pixel detection process for a radiation dose detection pixel performed by the control unit 106 according to the first modification. Note that the same processes as those in the above embodiment will be described with the same reference numerals.

  In step S100, the defect detection of the radiographic image capturing pixel 100A is performed, and the process proceeds to step S101. The defect detection of the radiation image capturing pixel 100A is performed by, for example, reading the value of the radiation image capturing pixel 100A in a state in which no radiation is irradiated and determining a pixel having a value different from other pixels by a predetermined value or more as a defective pixel. Alternatively, the value of the radiographic image capturing pixel 100A when radiation is irradiated under a predetermined imaging condition is read, and a value different from a reference value for the imaging condition by a predetermined threshold or more is output. The pixel may be determined as a defective pixel, or the defective pixel may be determined by applying another method.

  In step S101, the radiation dose of interest is calculated from the values of surrounding normal radiation image capture pixels 100A (in the first modification, the radiation image capture pixels 100A read before and after the focused radiation dose detection pixel 100B). A process of predicting the value of the detection pixel 100B is performed, and the process proceeds to step S104. In this process, it is determined from the defect detection result of the radiographic image capturing pixel 100A in step S100 whether there is a normal radiographic image capturing pixel 100A having no defect read before and after the target radiation dose detection pixel 100B. When there is a normal radiographic image capturing pixel 100A, the value of the target radiation dose detection pixel 100B is predicted from the value of the normal radiographic image capturing pixel 100A. When there is no normal radiation image capturing pixel, the target radiation irradiation amount detection pixel 100B is also determined to be defective.

  In step S104, it is determined whether the target radiation irradiation amount detection pixel 100B is a defective pixel. The determination is made, for example, by determining whether or not the value predicted from the radiographic image capturing pixel 100A differs from the actual value of the radiation irradiation amount detection pixel 100B by a predetermined threshold value or more. In the case, the process proceeds to step S106, and in the case of negative, the process proceeds to step S108.

  In step S106, the target radiation irradiation amount detection pixel 100B is set as a defective pixel, and the process proceeds to step S108.

  In step S108, it is determined whether or not the defect determination has been completed for all the radiation dose detection pixels 100B. If the determination is negative, the process proceeds to step S110. The defective pixel detection process for the detection pixel is terminated.

  In step S110, the target radiation irradiation amount detection pixel is changed, the process returns to step S102, and the above-described processing is repeated.

  Subsequently, a second modification example regarding defect determination of the radiation dose detection pixel 100B will be described. 12A is a diagram illustrating a pixel configuration of the second modification, FIG. 12B is a diagram illustrating a circuit configuration of the pixel of the second modification, and FIG. 12C is a modification of the pixel configuration. It is a figure which shows an example.

  In the above embodiment, the defect occurrence state of the surrounding eight radiation image capturing pixels 100A adjacent to the radiation irradiation amount detection pixel 100B is used as the periphery of the radiation irradiation amount detection pixel 100B. In the modified example, a case where a radiation dose detection pixel is configured as a sub-pixel will be described.

  In the above-described embodiment and the first modification, the radiation image capturing pixel 100A and the radiation irradiation amount detection pixel 100B exist as one pixel, but the radiation detector 26 of the second modification has one pixel. In addition, the radiation image capturing pixel 100A and the radiation dose detection pixel 100B exist as sub-pixels, respectively.

  That is, in the second modified example, as shown in FIGS. 12A and 12B, the radiation image capturing pixel 100A and the radiation irradiation amount detection pixel 100B are configured as a pair of sub-pixels. Yes. In the second modification, the radiation dose detection pixel 100 </ b> B has a configuration in which the sensor unit 103 is directly connected to the signal wiring 73 without providing the TFT switch 74. As a result, the charge of each sensor unit 103 can be read directly, and therefore, compared with the case where the sensor unit 106 and the signal wiring 73 are connected via the TFT switch 74, the radiation dose detection (AEC) can be quickly performed. It can be carried out.

  In addition, this modification is good also as a structure which has the pixel 100B for one radiation irradiation amount detection as a sub pixel with respect to the pixel 100A for several radiographic imaging, as shown in FIG.12 (C).

  Here, an example of processing performed by the control unit 106 of the electronic cassette 20 in the second modification will be described.

  FIG. 13 is a flowchart illustrating an example of a defective pixel detection process for a radiation dose detection pixel performed by the control unit 106 according to the second modification. Note that the same processes as those in the above embodiment will be described with the same reference numerals.

  In step S100, defect detection of the radiographic image capturing pixel 100A is performed, and the process proceeds to step S103. The defect detection of the radiation image capturing pixel 100A is performed by, for example, reading the value of the radiation image capturing pixel 100A in a state in which no radiation is irradiated and determining a pixel having a value different from other pixels by a predetermined value or more as a defective pixel. Alternatively, the value of the radiographic image capturing pixel 100A when radiation is irradiated under a predetermined imaging condition is read, and a value different from a reference value for the imaging condition by a predetermined threshold or more is output. The pixel may be determined as a defective pixel, or the defective pixel may be determined by applying another method.

  In step S103, the defect detection result of the radiation image capturing pixel 100A paired with the target radiation irradiation amount detection pixel 100B is acquired, and the process proceeds to step S104. That is, the defect detection result of the radiation image capturing pixel 100A that constitutes one pixel with the target radiation irradiation amount detection pixel 100B is acquired.

  In step S104, it is determined whether the target radiation irradiation amount detection pixel 100B is a defective pixel. In this determination, it is determined whether or not the radiation irradiation amount detection pixel 100B of interest and the radiographic image capturing pixel 100A constituting one pixel are defective pixels. If the determination is affirmative, the process proceeds to step S106, and the determination is negative. If so, the process proceeds to step S108. That is, when the target radiation irradiation amount detection pixel 100B and the radiation image capturing pixel 100A constituting one pixel are defective, they are the same pixel, so the radiation irradiation amount detection pixel 100B is also highly likely to be defective. Therefore, it is possible to determine the defect of the radiation dose detection pixel 100B from the surrounding radiation image capturing pixel 100A.

  In step S106, the target radiation irradiation amount detection pixel 100B is set as a defective pixel, and the process proceeds to step S108.

  In step S108, it is determined whether or not the defect determination has been completed for all of the radiation dose detection pixels. If the determination is negative, the process proceeds to step S110. If the determination is affirmative, a series of radiation dose detection is performed. The defective pixel detection process for the working pixel is terminated.

  In step S110, the target radiation irradiation amount detection pixel is changed, the process returns to step S102, and the above-described processing is repeated.

  In the above description, the embodiment and each modification have been described individually. However, the defect determination may be performed by combining the defect determination methods of the respective radiation dose detection pixels 100B. For example, the defective pixel determination of the radiation dose detection pixel of the first embodiment and the first modification may be performed, and the defective pixel may be set when the defective pixel is determined by both methods, If it is determined as a defective pixel by any method, it may be set as a defective pixel. Further, in the case of the pixel configuration as in the second modified example, the defective pixel determination of the radiation dose detection pixels in the embodiment, the first modified example, and the second modified example is performed, respectively, and the defect is detected in all methods When it is determined as a pixel, it may be set as a defective pixel, or when it is determined as a defective pixel by any method, it may be set as a defective pixel, or two or more If it is determined as a defective pixel by the method, it may be set as a defective pixel.

  In the above-described embodiment and each modification, the case where the present invention is applied to the radiation detector 26 of the indirect conversion type that converts the converted light into electric charges has been described, but the present invention is not limited to this. For example, the present invention may be applied to a direct-conversion radiation detector that uses a material that directly converts radiation X into charge, such as amorphous selenium, as a photoelectric conversion layer that absorbs radiation and converts it into charges.

  In addition, the configurations, operations, and the like of the radiographic imaging system 10, the radiation generator 12, the electronic cassette 20, and the radiation detector 26 described in the present embodiment are examples, and the scope of the present invention is not deviated. Needless to say, it can be changed according to the situation.

  Moreover, the radiation X in this Embodiment is not specifically limited, X-ray, a gamma ray, etc. can be applied.

  The processing shown in the flowcharts in the above embodiments may be stored and distributed as various programs in various storage media.

  Furthermore, in the above description, the defective pixel detection process of the radiation dose detection pixel has been described as a process performed by the control unit 106. However, the present invention is not limited to this, and may be a process performed by the radiation image processing device 14, for example. The processing performed by the console 16 may be performed.

DESCRIPTION OF SYMBOLS 10 Radiation imaging system 12 Radiation generator 14 Radiation image processing apparatus 16 Console 20 Electronic cassette 26 Radiation detector 100 Pixel 100A Radiation imaging pixel 100B Radiation irradiation amount detection pixel 106 Control part

Claims (11)

A plurality of radiation image capturing pixels for capturing a radiation image;
A radiation dose detection pixel for detecting the radiation dose,
Determination means for determining a defect of the radiation dose detection pixel based on a defect occurrence state of the radiation image pixel around the radiation dose detection pixel;
A radiographic imaging apparatus comprising: One pixel is configured with the radiation imaging pixel and the radiation dose detection pixel as sub-pixels,
The radiographic imaging device according to claim 1, wherein the determination unit determines a defect of the radiation dose detection pixel in the same pixel based on a defect occurrence state of the radiation imaging pixel constituting one pixel.   The determination means predicts a value of a pixel imaged by the radiation irradiation amount detection pixel from a value of the surrounding radiation image pixel when the surrounding radiation image pixel has no defect, and a predicted value The radiographic imaging device according to claim 1, wherein a defect of the radiation dose detection pixel is determined based on a pixel value of the radiation dose detection pixel. A signal line to which the radiation image capturing pixel and the radiation dose detection pixel are respectively connected;
The determination unit is connected to the same signal line as the radiation dose detection pixel, and is based on a defect occurrence state of the radiation image pixel read before and after the radiation dose detection pixel. The radiographic imaging apparatus of any one of Claims 1-3 which determine the defect of the pixel for irradiation amount detection.   The radiation image capturing pixel includes a sensor unit that generates a charge corresponding to the irradiated radiation, and a switching element that reads the charge generated by the sensor unit and outputs the charge to a signal line. The radiation image capturing apparatus according to claim 1, wherein the pixel includes a sensor unit that generates a charge corresponding to the irradiated radiation and outputs the generated charge to the signal line. The radiographic imaging apparatus according to any one of claims 1 to 5,
Radiation irradiating means for irradiating the radiation imaging apparatus with radiation through a subject;
Radiographic imaging system equipped with. In the radiation image capturing apparatus, comprising: a plurality of radiation image capturing pixels for capturing a radiation image; and a radiation irradiation amount detection pixel for detecting a radiation irradiation amount. An acquisition step of acquiring a defect occurrence status of the surrounding radiation image pixel;
A determination step of determining a defect of the radiation dose detection pixel based on the acquisition result of the acquisition step;
A method for determining a defect in a radiographic image capturing apparatus. The radiation imaging pixel and the radiation dose detection pixel are sub-pixels to form one pixel,
The radiographic imaging device according to claim 7, wherein the determination step determines a defect of the radiation dose detection pixel in the same pixel based on a defect occurrence state of the radiation imaging pixel constituting one pixel. Defect determination method.   The determination step predicts a value of a pixel imaged by the radiation irradiation amount detection pixel from a value of the surrounding radiation image pixel when the surrounding radiation image pixel has no defect, and a predicted value The defect determination method of the radiographic imaging apparatus of Claim 7 or Claim 8 which determines the defect of the said radiation irradiation amount detection pixel based on the value of the said radiation irradiation amount detection pixel. The radiographic image capturing apparatus further includes a signal line to which the radiographic image capturing pixel and the radiation irradiation amount detection pixel are connected,
The determination step is based on a defect occurrence state of the radiation image pixel connected to the same signal line as the radiation dose detection pixel and read before and after the radiation dose detection pixel. The defect determination method of the radiographic imaging apparatus of any one of Claims 7-9 which determines the defect of the pixel for irradiation amount detection.   A radiographic imaging program for causing a computer to function as the determination unit in the radiographic imaging apparatus according to any one of claims 1 to 5.