JP2013096730A - Radiographic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute reset processing so as to prevent a state where a radiographic image cannot be obtained.SOLUTION: A radiographic imaging device (10A) comprises: one or more radiation conversion panels (28a, 28b) capable of converting radiation (16) to a radiographic image; a reset processing units (30, 32) capable of executing reset processing for suppressing occurrence of an afterimage on the radiation conversion panels (28a, 28b); and a reset control unit (45) for controlling the reset processing units (30, 32) so as to execute the reset processing for at least two areas in the radiation conversion panels (28a, 28b) in time zones different from each other.

Description

  The present invention relates to a radiation imaging apparatus having a radiation conversion panel capable of converting radiation into a radiation image and capable of executing a reset process for suppressing the occurrence of an afterimage on the radiation conversion panel.

  In a radiation imaging apparatus having a radiation conversion panel capable of converting radiation into a radiation image, for example, Patent Documents 1 to 3 disclose that after-image generation is suppressed by executing reset processing on the radiation conversion panel. It is disclosed.

  The afterimage as an artifact with respect to the radiographic image acquired by the radiographic apparatus relates to the detection of radiation in the radiation conversion panel depending on the temperature, the driving time, the magnitude of the bias, and the magnitude of the tube voltage of the radiation source that outputs the radiation. This occurs due to a change in response characteristics. In addition, in an indirect conversion type radiation conversion panel that converts radiation into fluorescence and then converts it into electric charge, in the photoelectric conversion element that converts fluorescence into electric charge, the impurity level (defect) of the semiconductor constituting the photoelectric conversion element is one. Once the captured charge is captured and the captured partial charge is output together with the charge corresponding to the original image information, the afterimage is displayed on the display device together with the image information. Sometimes it ends up. Furthermore, the charge resulting from the dark current also causes afterimages.

JP 2009-5374 A JP 2010-246835 A JP 2011-66514 A

  By the way, in radiation imaging (moving image capturing) in which radiation irradiation is repeatedly performed on the radiation imaging apparatus, the above-described afterimage may be superimposed on the radiation image (moving image) unless the reset process is performed a certain number of times. is there.

  However, if the frame rate of moving image shooting is increased and the shooting interval is shortened, it is difficult to execute the reset process when radiation is not irradiated, and the reset process must be performed during radiation irradiation.

  The reset processes of Patent Documents 1 to 3 described above all read out charges accumulated in the radiation conversion panel and discharge them to the ground. Such reset processes are performed during radiation irradiation in an arbitrary frame. When executed, a desired moving image cannot be acquired in the frame.

  Therefore, for example, when an operator performs a predetermined operation while watching a moving image (for example, when a doctor performs an operation of inserting a catheter into a patient while watching a moving image), during irradiation of radiation in an arbitrary frame When the reset process is executed, the work must be interrupted until the next moving image is acquired.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a radiation imaging apparatus that can execute a reset process so that a state in which a radiation image cannot be acquired does not occur. .

  In order to achieve the above object, a radiation imaging apparatus according to the present invention includes at least one radiation conversion panel capable of converting radiation into a radiation image, and a reset for suppressing generation of an afterimage for the radiation conversion panel. A reset processing unit capable of executing processing, and a reset control unit that controls the reset processing unit to execute the reset processing for at least two regions in the radiation conversion panel in different time zones. It is said.

  According to this configuration, when performing radiography using the radiation conversion panel, the reset processing timings for the at least two regions in the radiation conversion panel are shifted, and the reset processing is executed in different time zones. I am doing so. As described above, in the present invention, the reset control unit controls the reset processing unit so that time zones for executing the reset processing on the at least two regions do not overlap each other. Thereby, it is possible to acquire a radiation image in the other region while executing the reset process on the one region. As a result, it is possible to avoid a state in which a radiation image cannot be acquired by the reset process.

  Here, when a moving image as the radiation image is acquired by repeatedly performing the irradiation of the radiation, the reset control unit switches an area in which the reset process is executed every predetermined number of frames. The reset processing unit may be controlled.

  As a result, in each frame, a moving image in which only the area where the reset process is executed is acquired, but the area where the reset process is executed is switched for each predetermined number of frames. It is possible to avoid a situation in which the reset process is repeatedly executed only on the area, and a moving image of the specific area cannot be obtained.

  That is, in the present invention, the reset process is not performed on the entire image area in the radiation conversion panel, but only on a part of the area, so the frame rate of the moving image is increased. However, it is possible to avoid the occurrence of a frame in which the entire image area is lost, and it is possible to reliably acquire moving images in all frames.

  Therefore, if the moving image is displayed on an external display device or the like, an operator who performs a predetermined operation while viewing the moving image (for example, performing an operation of inserting a catheter into a patient while viewing the moving image) Doctor) can complete the work without interrupting the work.

  In addition, since the area where the reset process is executed is switched every predetermined number of frames, the missing area of the image in the moving image moves every predetermined number of frames.

  Here, the radiation conversion panel has a plurality of pixels arranged in a matrix for converting the radiation into electric charges and storing them. In this case, the reset processing for each pixel and the acquisition of the moving image may be performed as described in [1] to [3] below.

  [1] The at least two areas each include one or more pixels, and when a moving image of one frame is acquired, the reset process is performed on one area, and the other area It is preferable that a moving image is acquired.

  [2] In the case of [1], the at least two regions are a region composed of pixels of odd lines and a region composed of pixels of even lines among the plurality of pixels arranged in a matrix. The reset control unit performs reset processing on the odd-line pixels and acquisition of moving images at the even-line pixels, and acquisition of moving images at the odd-line pixels and the even-line pixels for each frame. It is preferable to control the reset processing unit so as to alternately switch to the reset processing for.

  [3] In the case of [1], the at least two regions are each configured by pixels of at least one line among the plurality of pixels arranged in the matrix, and intersect with each line. The reset control unit, for each frame, the reset processing for the odd-numbered area, the acquisition of the moving image in the even-numbered area, and the odd-numbered area It is preferable to control the reset processing unit so as to switch alternately between acquisition of a moving image and reset processing for the even-numbered region.

  In any of the cases [1] to [3], the acquisition of a moving image from the pixels in one region and the reset processing for the pixels in the other region are performed in an interlaced manner. In addition, in the case of moving image shooting, if any one of the processes [1] to [3] is performed, the reset process for all the regions (all pixels) is completed with a predetermined number of shootings, so that the occurrence of afterimages is suppressed. High-quality moving images can be easily acquired.

  With regard to the moving image shooting described above, if image signals corresponding to the moving images of the two frames before and after are added by the image processing unit provided in the radiation imaging apparatus or an external image processing apparatus, there is no image missing area. In addition, a high-quality moving image can be formed. As a result, the operator can smoothly perform a predetermined operation while viewing the moving image displayed on the display device.

  In each of the above inventions, the radiation imaging apparatus may have a configuration in which two radiation conversion panels are stacked. Therefore, if each radiation conversion panel has the above-described configuration and functions, the above-described effects can be easily obtained.

  In this case, in the radiation imaging apparatus, a first radiation conversion panel and a second radiation conversion panel are sequentially stacked along the incident direction of the radiation, and the reset control unit is configured to perform the radiation conversion in a plan view. What is necessary is just to control the said reset process part so that the said reset process with respect to the same area | region of a panel may not be performed in the same time slot | zone.

  According to this configuration, when performing radiography using the two radiation conversion panels, the reset processing timing is shifted for the same region in plan view, and the reset processing is executed in different time zones. Like to do. That is, the reset control unit controls the reset processing unit so that the time zones for executing the reset processing on the same region do not overlap each other. Thereby, it is possible to acquire a radiation image in the region of the other radiation conversion panel while executing the reset process for the region of one radiation conversion panel. As a result, it is possible to avoid a state in which the radiation image cannot be acquired in the same region by the reset process.

  Furthermore, in the radiographic apparatus having the two radiation conversion panels, each of the radiation conversion panels includes a plurality of pixels arranged in a matrix that converts the radiation into electric charges and stores the charges. The pixel density of the radiation conversion panel and the pixel density of the second radiation conversion panel may be different from each other.

  Even in this case, it is possible to execute moving image acquisition from one region (each pixel) and reset processing for the other region (each pixel) by the interlace method. In the case of moving image shooting, a high-quality moving image in which the occurrence of afterimages is suppressed can be easily acquired by performing the above-described reset process.

  Further, an image signal corresponding to the radiation image acquired by the first radiation conversion panel and the second radiation conversion panel is added by an image processing unit provided in the radiation imaging apparatus or an external image processing apparatus. For example, a high-quality moving image that does not include an image-missing frame can be formed. As a result, the operator can smoothly perform a predetermined operation while viewing the moving image displayed on the display device.

  Further, in the above radiographic apparatus, the reset processing unit includes: a driving circuit unit that switches the pixels to a storage state in which the charge can be stored or a read state in which the stored charge can be read; A readout circuit unit that reads out charges from a pixel in a state, and the drive circuit unit switches the pixels to the readout state, and the readout circuit unit reads out the charges accumulated in the pixels and discharges them to the ground. Thus, a reset process for each pixel may be executed.

  As described above, if the reset process for reading out the electric charge accumulated in each pixel and releasing it to the ground is performed, the occurrence of an afterimage in each pixel can be effectively suppressed.

  According to the present invention, when performing radiography using a radiation conversion panel, the reset processing timing for at least two regions in the radiation conversion panel is shifted, and the reset processing is executed in different time zones. ing. Thus, in the present invention, the reset control unit controls the reset processing unit so that the time zones in which the reset processing is performed on the at least two areas do not overlap each other. Thereby, it is possible to acquire a radiation image in the other region while executing the reset process on the one region. As a result, it is possible to avoid a state in which a radiation image cannot be acquired by the reset process.

1 is a configuration diagram of a radiation imaging system having a radiation imaging apparatus according to a first embodiment. It is a typical circuit block diagram of the radiography apparatus of FIG. It is a perspective view which shows typically the electrical connection in the radiation detector of FIG. It is a circuit diagram which shows the electrical connection for 1 pixel of a 1st radiation conversion panel. It is a circuit diagram which shows the electrical connection for 1 pixel of a 2nd radiation conversion panel. It is explanatory drawing which shows schematic structure of the radiation detector of FIG. It is explanatory drawing which showed typically the structure for 1 pixel (for 1 pixel of the 1st radiation conversion panel and for 1 pixel of the 2nd radiation conversion panel) of the radiation detector of FIG. It is explanatory drawing which showed typically irradiation of the radiation | emission with respect to the structure for 1 pixel of FIG. It is explanatory drawing which showed typically irradiation of the radiation | emission with respect to the structure for 1 pixel of FIG. It is explanatory drawing which showed typically execution of the reset process with respect to each pixel. It is a time chart which shows irradiation of radiation, acquisition of the radiation image in a radiation conversion panel, and execution of the reset process with respect to a radiation conversion panel. It is a time chart which shows irradiation of radiation, acquisition of the radiation image in a radiation conversion panel, and execution of the reset process with respect to a radiation conversion panel. It is explanatory drawing which showed typically execution of the reset process for every area | region. It is a block diagram of the radiography system which has the radiography apparatus which concerns on 2nd Embodiment. 15A and 15B are explanatory diagrams schematically showing the execution of the reset process for each pixel. It is a time chart which shows irradiation of radiation, acquisition of the radiation image in a radiation conversion panel, and execution of the reset process with respect to a radiation conversion panel.

  A preferred embodiment (first and second embodiments) of a radiation imaging apparatus according to the present invention will be described in detail below with reference to FIGS.

[Configuration of First Embodiment]
As shown in FIG. 1, a radiation imaging system 12A including a radiation imaging apparatus 10A according to the first embodiment includes a radiation output device 18 that irradiates a subject 16 with radiation 16 and radiation 16 that has passed through the subject 14. A radiation imaging apparatus 10A that detects and converts to a radiation image, a console 20 that controls the radiation imaging apparatus 10A and the radiation output apparatus 18, and a display device 22 that displays the radiation image are provided.

  Between the console 20 and the radiation imaging apparatus 10A, the radiation output apparatus 18 and the display apparatus 22, for example, UWB (Ultra Wide Band), IEEE802.60. Signals are transmitted / received by wireless LAN (Local Area Network) such as a / b / g / n or wireless communication using millimeter waves or the like. It goes without saying that signals may be transmitted and received by wired communication using a cable.

  The console 20 is connected to a radiology information system (RIS) 24 that comprehensively manages radiographic images and other information handled in the radiology department in the hospital. Connected to the RIS 24 is a medical information system (HIS) 26 that comprehensively manages medical information in the hospital.

  The radiation imaging apparatus 10A according to the first embodiment includes, for example, a radiation detector 28 that is disposed between an imaging table (not shown) and a subject 14 and converts radiation 16 transmitted through the subject 14 into a radiation image. It is a portable electronic cassette housed in a transmissive case.

  The radiation imaging apparatus 10 </ b> A controls the radiation detector 28 through the radiation detector 28 and the drive circuit unit 30 described above, and an image signal (in accordance with the radiation image from the radiation detector 28 through the readout circuit unit 32). A cassette control unit 34 for reading out charge signals and electrical signals), a communication unit 36 that transmits and receives signals to and from the console 20, and a battery 38 that supplies power to each unit in the radiation imaging apparatus 10A are accommodated in the housing. doing.

  The radiation detector 28 sequentially stacks a first radiation conversion panel (one radiation conversion panel) 28 a and a second radiation conversion panel (the other radiation conversion panel) 28 b along the incident direction of the radiation 16. Configured.

  The first radiation conversion panel 28a mainly absorbs a low energy component of the radiation 16 and directly converts the absorbed energy component into a charge, thereby generating a first radiation image (moving image or still image) corresponding to the charge. It is a direct conversion type radiation conversion panel to be formed. The second radiation conversion panel 28b mainly absorbs the high energy component of the radiation 16, temporarily converts the absorbed energy component into fluorescence, and converts the converted fluorescence into electric charge. It is an indirect conversion type radiation conversion panel which forms a radiation image (moving image).

  The low energy component of the radiation 16 is an energy component of the radiation 16 corresponding to the low voltage when the tube voltage of the radiation source constituting the radiation output device 18 is relatively low. It is easily absorbed by mammo, soft tissue or tumor. The high energy component of the radiation 16 is an energy component of the radiation 16 corresponding to the high voltage when the tube voltage of the radiation source is relatively high, and is easily absorbed by the bone portion of the subject 14. .

  Further, the radiation imaging apparatus 10A includes a voltage supply unit 42 that supplies a DC voltage necessary for taking out the charges converted in the first radiation conversion panel 28a to the first radiation conversion panel 28a, and a second radiation. A bias power source 40 is also provided for supplying a bias voltage (DC voltage) necessary for converting fluorescence into electric charge in the conversion panel 28b to the second radiation conversion panel 28b.

  The cassette control unit 34 reads an address signal for instructing the radiation detector 28 to read out a radiation image to the drive circuit unit 30, and reads out from the radiation detector 28 under the control of the drive circuit unit 30. An image memory 46 that stores the radiation image read out via the circuit unit 32 and a cassette ID memory 48 that stores cassette ID information for specifying the radiation imaging apparatus 10A are provided.

  The cassette control unit 34 further includes a reset control unit 45 and an image processing unit 47. The reset control unit 45 controls the drive circuit unit 30 and the readout circuit unit 32 via the address signal generation unit 44, thereby performing a predetermined reset process on the first radiation conversion panel 28a or the second radiation conversion panel 28b. Let it run. Therefore, the drive circuit unit 30 and the readout circuit unit 32 function as a reset processing unit that can execute a reset process on the first radiation conversion panel 28a or the second radiation conversion panel 28b. Details of the reset process will be described later. On the other hand, the image processing unit 47 applies the radiation image of the first radiation conversion panel 28a and the radiation image of the second radiation conversion panel 28b read out from the radiation detector 28 via the readout circuit unit 32. Then, predetermined image processing such as addition processing is performed.

  The console (image processing apparatus) 20 includes a communication unit 50, a control processing unit 52, an order information storage unit 54, an imaging condition storage unit 56, an image processing unit 58, and an image memory 60.

  The communication unit 50 transmits / receives signals to / from the communication unit 36, the radiation output device 18, the display device 22, and the RIS 24. The control processing unit 52 executes predetermined control processing for controlling each unit in the console 20. The order information storage unit 54 stores order information for requesting radiographic imaging (radiographic imaging) of the subject 14. The imaging condition storage unit 56 stores imaging conditions for irradiating the subject 14 with the radiation 16 and the like. The image processing unit 58 performs predetermined image processing (for example, addition processing similar to the addition processing in the image processing unit 47) on the radiation image received by the communication unit 50 from the communication unit 36. The image memory 60 stores a radiation image or the like that has been subjected to image processing by the image processing unit 58.

  Note that the order information is created by a doctor in the RIS 24 or HIS 26 and used for radiographic imaging in addition to subject information for identifying the subject 14 such as the name, age, and sex of the subject 14. Information of the radiation output device 18 and the radiation imaging apparatus 10A, the imaging region and imaging method of the subject 14, and the like. The imaging conditions are various conditions necessary for irradiating the imaging region of the subject 14 with the radiation 16 such as the tube voltage and tube current of the radiation source and the exposure time of the radiation 16.

  FIG. 2 is a schematic circuit configuration diagram of the radiation detector 28 and the like constituting the radiation imaging apparatus 10A.

  As described above, the radiation detector 28 has a stacked structure in which the first radiation conversion panel 28a and the second radiation conversion panel 28b are sequentially stacked in the incident direction of the radiation 16 (see FIG. 1). The radiation detector 28 has a structure in which a plurality of pixels 62 (62a, 62b) are arranged in a matrix in the plan view of FIG.

  In this case, each pixel 62 includes a part of the first radiation conversion panel 28a (pixel 62a) and a part of the second radiation conversion panel 28b (pixel 62b) along the incident direction of the radiation 16. It is configured (see FIG. 1). That is, the first radiation conversion panel 28a has a plurality of pixels 62a arranged in a matrix, and the second radiation conversion panel 28b has a plurality of pixels 62b arranged in a matrix. Accordingly, the pixel 62a directly converts the low energy component of the radiation 16 into electric charge, and the pixel 62b converts the high energy component of the radiation 16 into fluorescent light and then converts it into electric charge.

  In the radiation detector 28 (each radiation conversion panel 28a, 28b), a plurality of gate lines 64a, 64b extend in parallel to the row direction, and a plurality of signal lines 66a, 66b extend in parallel to the column direction. . The gate lines 64 a and 64 b are connected to the drive circuit unit 30, and the signal lines 66 a and 66 b are connected to the readout circuit unit 32.

  In FIG. 2, for ease of explanation, the gate line 64a and the gate line 64b are illustrated so as not to overlap with each other, and the signal line 66a and the signal line 66b are illustrated not to overlap with each other. As shown in FIG. 3, the pixel 62a and the pixel 62b, the gate line 64a and the gate line 64b, and the signal line 66a and the signal line 66b are arranged so as to overlap each other.

  Specifically, in the first radiation conversion panel 28a, for each pixel 62a arranged in the row direction, one gate line connected to the thin film transistor (TFT) 82a (see FIG. 4) of each pixel 62a. 64a is arranged, and for each pixel 62a arranged in the column direction, one signal line 66a connected to the TFT 82a of each pixel 62a is arranged. Therefore, in the first radiation conversion panel 28a in which the plurality of pixels 62a are arranged in a matrix, gate lines 64a corresponding to the number of rows and signal lines 66a corresponding to the number of columns are disposed.

  Similarly to the first radiation conversion panel 28a, the second radiation conversion panel 28b is connected to the TFT 82b (see FIG. 5) of each pixel 62b with respect to each pixel 62b arranged in the row direction. One gate line 64b is provided, and one signal line 66b connected to the TFT 82b of each pixel 62b is provided for each pixel 62b arranged in the column direction. Therefore, also in the second radiation conversion panel 28b, gate lines 64b corresponding to the number of rows and signal lines 66b corresponding to the number of columns are provided.

  4 and 5 illustrate electrical connections to one pixel 62a and 62b, respectively. 4 and 5 have substantially the same configuration except that the internal configurations of the pixels 62a and 62b are different.

  In FIG. 4, the pixel 62a includes a first radiation detection unit 72a and a TFT 82a. The first radiation detection unit 72a includes a semiconductor made of amorphous selenium (a-Se), and is connected to the voltage supply unit 42 and the TFT 82a. When the radiation 16 is incident on the pixel 62a, the a-Se semiconductor constituting the first radiation detection unit 72a directly converts the incident radiation 16 into an electric charge and accumulates it. The accumulated charge can be taken out to the TFT 82a side due to the supply of the DC voltage from the voltage supply unit 42 to the first radiation detection unit 72a.

  When an address signal is supplied from the address signal generation unit 44 of the cassette control unit 34 (see FIGS. 1 and 2) to the drive circuit unit 30, the drive circuit unit 30 arranges the gate lines 64a in the row direction. A control signal for ON / OFF control of the TFT 82a is supplied. When the TFT 82a is turned on, the charge held in the first radiation detection unit 72a connected to the TFT 82a flows out to the readout circuit unit 32 as a charge signal through the TFT 82a and the signal line 66a.

  The read circuit unit 32 includes a charge amplifier 110a and an A / D converter 112a. The charge amplifier 110a includes an operational amplifier 116a, a capacitor 118a, and a switch 120a. When the switch 120a is off, the charge amplifier 110a converts the charge signal input to the operational amplifier 116a into a voltage signal, and amplifies the voltage signal with a preset gain or a gain set by the reset control unit 45. And output. The output voltage signal is A / D converted by the A / D converter 112 a and supplied to the cassette control unit 34.

  By the way, the reset control unit 45 can control the drive circuit unit 30 and the readout circuit unit 32 via the address signal generation unit 44 to execute a reset process on the first radiation conversion panel 28a. In the following description, the reset process executed due to the control of the drive circuit unit 30 and the read circuit unit 32 by the reset control unit 45 is also referred to as an electrical reset process for convenience.

  Specifically, when the electrical reset process is executed on the first radiation conversion panel 28a, the reset control unit 45 controls the address signal generation unit 44 to send an address signal instructing the drive circuit unit 30 to start the reset process. By supplying it, a control signal is supplied from the drive circuit unit 30 to the gate line 64a to turn on the TFT 82a. The reset control unit 45 also turns on the switch 120a of the charge amplifier 110a constituting the readout circuit unit 32 via the address signal generation unit 44.

  Thereby, the electric charge accumulated in the capacitor 118a is discharged by the closed circuit of the capacitor 118a and the switch 120a, and the electric charge accumulated in the pixel 62a (the semiconductor of the first radiation detection unit 72a constituting) is The light is discharged to the ground through the TFT 82a, the switch 120a, and the operational amplifier 116a.

  That is, the response characteristics regarding the radiation detection in the first radiation conversion panel 28a change depending on the temperature, the driving time, the magnitude of the DC voltage, and the magnitude of the tube voltage of the radiation source that outputs the radiation 16. In some cases, an afterimage may occur as an artifact with respect to the first radiation image. Even in a state where the radiation 16 is not irradiated on the pixel 62a, the charge due to the dark current is accumulated in the pixel 62a, which may cause an afterimage.

  Therefore, the TFT 82a and the switch 120a are turned on under the control of the reset control unit 45, and electric charges that cause the afterimage are discharged to the ground, thereby preventing the pixel 62a from generating afterimages. Processing can be performed. In the electrical reset process, the voltage signal corresponding to the charge accumulated in the pixel 62a is discarded without being output to the A / D converter 112a. That is, the charge signal read to the readout circuit unit 32 by the electrical reset process is not output to the cassette control unit 34 as an image signal indicating a radiation image.

  On the other hand, in FIG. 5, the pixel 62 b includes a scintillator that is a second radiation detection unit 72 b (see FIGS. 6 and 7), a photodiode (light detection element) 86 b, and a TFT 82 b. The photodiode 86b includes a semiconductor such as amorphous silicon (a-Si), and is connected to the bias power supply 40 and the TFT 82b. When the radiation 16 is incident on the pixel 62b, the scintillator of the pixel 62b converts the radiation 16 into fluorescence, and the photodiode 86b converts the fluorescence into electric charge and accumulates it. The accumulated charge can be extracted to the TFT 82b side due to the supply of the bias voltage from the bias power supply 40 to the photodiode 86b.

  A control signal for controlling on / off of the TFTs 82b arranged in the row direction from the drive circuit unit 30 to the gate line 64b due to the supply of the address signal from the address signal generation unit 44 (see FIG. 1) to the drive circuit unit 30. Is turned on, the charge of the photodiode 86b connected to the TFT 82b flows out to the readout circuit portion 32 through the TFT 82b and the signal line 66b.

  The read circuit unit 32 further includes a charge amplifier 110b and an A / D converter 112b. Similarly to the charge amplifier 110a, the charge amplifier 110b includes an operational amplifier 116b, a capacitor 118b, and a switch 120b. Therefore, when the switch 120b is off, the charge amplifier 110b converts the charge signal input to the operational amplifier 116b into a voltage signal, and the voltage signal with a preset gain or a gain set by the reset control unit 45. Is amplified and output. The output voltage signal is A / D converted by the A / D converter 112 b and supplied to the cassette control unit 34.

  Similarly to the case of the first radiation conversion panel 28a, the electrical reset process can be executed for the second radiation conversion panel 28b.

  In this case, the reset control unit 45 controls the address signal generation unit 44 to supply an address signal instructing the drive circuit unit 30 to start the reset process, so that the control signal is sent from the drive circuit unit 30 to the gate line 64b. Then, the TFT 82b is turned on, and the switch 120b of the charge amplifier 110b is also turned on via the address signal generator 44.

  As a result, the charge accumulated in the capacitor 118b is discharged by the closed circuit of the capacitor 118b and the switch 120b, and the charge accumulated in the photodiode 86b constituting the pixel 62b is passed through the TFT 82b, the switch 120b, and the operational amplifier 116b. To the ground.

  That is, also in the second radiation conversion panel 28b, the radiation detection in the second radiation conversion panel 28b depends on the temperature, the driving time, the magnitude of the bias voltage, and the magnitude of the tube voltage of the radiation source that outputs the radiation 16. Due to the change in the response characteristics, an afterimage may occur as an artifact with respect to the second radiation image. Further, some charges are once captured by impurity levels (defects) of the semiconductor (for example, a-Si) constituting the photodiode 86b, and the captured charges are captured in the next image. By outputting together with the charge corresponding to the information, it may be displayed on the display device 22 together with the image information as an afterimage. Further, in a state where the radiation 16 is not irradiated to the pixel 62b, the charge due to the dark current is accumulated in the pixel 62b, which may cause afterimage.

  Therefore, the TFT 82b and the switch 120b are turned on under the control of the reset control unit 45, and the charge causing the afterimage is discharged to the ground, thereby suppressing the afterimage from being generated even for the pixel 62b. Electrical reset processing can be performed. Even in the electrical reset processing for the second radiation conversion panel 28b, the voltage signal corresponding to the electric charge accumulated in the pixel 62b is discarded without being output to the A / D converter 112b, and the radiation image is converted. The image signal is not output to the cassette control unit 34.

  4 and 5, the charge accumulation and readout in one pixel 62a and 62b and the electric reset process for one pixel 62a and 62b have been described.

  The radiation conversion panels 28a and 28b actually have a plurality of pixels 62a and 62b arranged in a matrix as shown in FIG. 2 and FIG. In one reset process, (1) all the pixels 62a of the first radiation conversion panel 28a are targeted, or (2) some (specific) pixels of the first radiation conversion panel 28a 62a, or (3) all pixels 62b of the second radiation conversion panel 28b, and / or (4) a (specific) part of the second radiation conversion panel 28b. This is performed for the pixel 62b.

  In the case of the electrical reset process, for example, the reset process can be performed as follows. That is, each of the pixels 62a and 62b can be switched between the accumulation state and the readout state by the on / off control (line control for each row) of the TFTs 82a and 82b by the drive circuit unit 30 and the readout circuit unit 32. Therefore, the reset control unit 45 may perform the reset process as in the following (1) to (5) in one electric reset process.

  (1) The reset control unit 45 may perform the electrical reset process for all the pixels 62a and 62b at the same time by turning on all the TFTs 82a and 82b.

  (2) The reset control unit 45 may turn on the TFTs 82a and 82b sequentially for each row and sequentially perform the electrical reset processing for the pixels 62a and 62b for each row.

  (3) If the reset controller 45 sequentially turns on the TFTs 82a and 82b for each odd row or even row and performs the electrical reset process for the pixels 62a and 62b sequentially for every odd row or even row by the interlace method. Good.

  (4) One or more lines of pixels 62a and 62b (in the case of FIGS. 2 and 3, one or more rows of pixels 62a and 62b) are combined to form one region, and such regions are orthogonal to the lines. Arrange multiple in the direction. Then, the reset control unit 45 may perform the electrical reset process for each region (the pixels 62a and 62b) sequentially for each region.

  (5) For the plurality of areas described in (4) above, the reset control unit 45 uses the interlace method to generate electricity for each area (pixels 62a and 62b) for each odd-numbered area or even-numbered area. The reset process may be performed sequentially.

  In the following description, unless otherwise specified, the electrical reset process is described as being performed by any one of the methods (3) to (5).

  FIG. 6 schematically shows a laminated structure of the radiation detector 28. That is, FIG. 6 shows the first radiation conversion panel 28a of the direct conversion type of the ISS (Irradiation Side Sampling) method as the surface reading method and the PSS (Penetration) as the back surface reading method along the incident direction of the radiation 16. A configuration in which second radiation conversion panels 28b of an indirect conversion type of Side Sampling method are sequentially stacked is illustrated.

  The first radiation conversion panel 28a sequentially stacks an insulating substrate 68a, a first charge detection unit (charge extraction unit) 70a, and a first radiation detection unit 72a along the incident direction of the radiation 16. Configured. In addition, the second radiation conversion panel 28b is directed toward the first radiation conversion panel 28a (from the lower direction to the upper direction in FIG. 6) and the second charge detection unit (the second charge detection unit). An optical detection unit) 70b and a second radiation detection unit 72b are sequentially stacked.

  Since the insulating substrate 68a absorbs the radiation 16 in the first radiation detecting unit 72a and the second radiation detecting unit 72b, the insulating substrate 68a has a low electric absorption property of the radiation 16 and has a thin and electrically insulating property. A substrate (a substrate having a thickness of about several tens of μm), specifically, a synthetic resin, aramid, bionanofiber, or a film-like glass (ultra-thin glass) that can be wound into a roll. preferable.

  The first radiation detector 72a includes a semiconductor layer 74a made of a-Se, a plurality of pixel electrodes 76a formed on one surface of the semiconductor layer 74a on the first charge detector 70a side, and the other surface of the semiconductor layer 74a. And a common electrode 78a formed so as to cover the entire surface.

  The pixel electrode 76a is formed for each pixel 62 (62a), has a low absorbability with respect to the radiation 16, and does not generate electromigration with a-Se (for example, Au). Preferably it consists of. When the radiation 16 is incident, the a-Se semiconductor layer 74a absorbs a low energy component of the radiation 16 and converts it into electric charges. While the common electrode 78a detects the high energy component of the radiation 16 in the second radiation detection unit 72b, at least a of the fluorescence converted from the radiation 16 by the second radiation conversion panel 28b as described later. In order to transmit light in the sensitivity wavelength region of Se (for example, light in the blue wavelength region), the absorption of the radiation 16 is low, electromigration does not occur with a-Se, and the sensitivity wavelength It is preferably made of a conductive material that can transmit light in the region, for example, ITO (Indium Tin Oxide).

  Note that when the pixel electrode 76a and the common electrode 78a are formed, a-Se may be crystallized depending on the formation temperature. Therefore, in order to suppress crystallization of a-Se, it is necessary to form the pixel electrode 76a and the common electrode 78a at as low a temperature as possible. Therefore, the pixel electrode 76a and the common electrode 78a are desirably formed as an organic film or an organic conductor containing a metal filler by coating, roll-to-roll, ink jet, or the like.

  The first charge detection unit 70a is configured to include the TFT 82a (see FIGS. 4 and 7) described above, and the charge generated in the semiconductor layer 74a is taken out for each pixel 62a via each pixel electrode 76a. Is output as an electrical signal (analog signal) to the readout circuit section 32 via a signal line 66a (see FIGS. 2 to 4). In addition, the first charge detection unit 70a is preferably made of a material having low absorption of the radiation 16 so that the first radiation detection unit 72a and the like detect the radiation 16. Further, since the gate line 64a and the signal line 66a are connected to the TFT 82a, the gate line 64a and the signal line 66a also have a low resistance to radiation 16 and a low resistance conductive material (for example, Al) is preferred.

The 2nd radiation detection part 72b consists of a scintillator which converts the high energy component of the incident radiation 16 into fluorescence. As the scintillator, light in the a-Se sensitivity wavelength region or light in a wavelength region that can be absorbed by the second charge detection unit 70b (light having a longer wavelength than light in the a-Se sensitivity wavelength region) can be generated. Such a scintillator that generates fluorescence having a relatively wide wavelength range 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 the like, and CsI: Na is more preferable.

  The second charge detection unit 70b includes a TFT 82b (see FIGS. 5 and 7) and a photodiode 86b. The second charge detection unit 70b converts the fluorescence converted by the scintillator into a charge, and converts the converted charge into an electric signal as a signal line 66b. Is output to the readout circuit section 32 via The low energy component of the radiation 16 is absorbed by the a-Se semiconductor layer 74a and converted into electric charges, and the high energy component of the radiation 16 is absorbed by the scintillator of the second radiation detection unit 72b and converted into fluorescence. Therefore, the TFT 82b and the photodiode 86b of the second charge detection unit 70b may not use a material having low radiation 16 absorption. Further, the gate line 64b and the signal line 66b connected to the TFT 82b may not use a conductive material having low radiation 16 absorption.

  Further, the second charge detection unit 70b that is unlikely to reach the radiation 16 is replaced with the combination of the TFT 82b and the photodiode 86b described above, and has a low resistance to the radiation 16 (CMOS (Complementary Metal-Oxide Semiconductor). Another imaging element such as an image sensor may be combined with the TFT 82b. Further, it can be replaced by a CCD (Charge-Coupled Device) image sensor that transfers charges while shifting the charges by a shift pulse corresponding to the gate signal referred to in the TFT 82b.

  The insulating substrate 68b is preferably a flexible, electrically insulating thin substrate. For example, the insulating substrate 68b may be made of the same material as the insulating substrate 68a described above. Note that since the possibility that the radiation 16 reaches the insulating substrate 68b is low, the insulating substrate 68b may not use a material having low absorbability with respect to the radiation 16.

  FIG. 7 schematically illustrates the radiation detector 28 of FIG. 6 in an enlarged manner to one pixel 62 (pixels 62a and 62b).

  As described above, one pixel 62 includes the pixel 62a including a part of the first radiation conversion panel 28a and the pixel 62b including a part of the second radiation conversion panel 28b.

  Specifically, one pixel electrode 76a configuring the first radiation detection unit 72a is assigned to one pixel 62a.

  The first charge detection unit 70 a has an array of TFTs 82 a disposed on the surface of the insulating substrate 68 a on the first radiation detection unit 72 a side, and one TFT 82 a is assigned to one pixel 62. It has been. In this case, when an array of TFTs 82a is formed on the insulating substrate 68a, the first radiation detecting portion 72a side of the insulating substrate 68a becomes uneven, so that, for example, a flattening process using a tetrafluoroethylene resin film is performed. It is desirable to form the planarizing film 84a.

The TFT 82a connected to the gate line 64a and the signal line 66a (see FIGS. 2 to 4) has an a-Si, amorphous oxide (e.g., a-IGZO (for example) in order to suppress absorption of the radiation 16 in the TFT array. InGaZnO ₄ )), an organic semiconductor material, and an active layer made of carbon nanotubes are preferably included.

  In this case, since a-Si needs to be formed at a substrate temperature of about 300 ° C., a glass substrate is used as the insulating substrate 68a. On the other hand, since a-IGZO and organic semiconductor can be formed by a low temperature process at a substrate temperature of about 200 ° C., a resin substrate such as polyimide or aramid can be used as the insulating substrate 68a. As a result, a flexible TFT array can be realized.

  The pixel electrode 76a and the common electrode 78a are electrically connected to the voltage supply unit 42.

  On the other hand, the second charge detection unit 70b has an array of TFTs 82b and photodiodes 86b disposed on the surface of the insulating substrate 68b on the second radiation detection unit 72b side, and one for one pixel 62b. One TFT 82b and one photodiode 86b are allocated. Also in this case, when the array of the TFTs 82b and the photodiodes 86b is formed on the insulating substrate 68b, the second radiation detector 72b side of the insulating substrate 68b becomes uneven, so that the same planarization as the planarizing film 84a is performed. It is desirable to form the film 84b.

  The TFT 82b connected to the gate line 64b and the signal line 66b preferably includes an active layer similar to the TFT 82a.

  Further, in FIG. 7, a scintillator of CsI: Na (sodium-activated cesium iodide) is illustrated as the second radiation detection unit 72b. The CsI: Na scintillator is formed by forming CsI: Na as a strip-like columnar crystal structure 88b by a vacuum evaporation method, and the base end portion of the scintillator on the flattened film 84b side is a non-columnar crystal portion 90b. It is in close contact with the planarizing film 84b. By providing the non-columnar crystal portion 90b, the adhesion between the scintillator of the second radiation detection unit 72b and the second charge detection unit 70b and the insulating substrate 68b can be improved. Moreover, the reflection of the fluorescence 98 (refer FIG. 8) mentioned later can be suppressed by making the porosity of the non-columnar crystal part 90b close to 0% or reducing the thickness thereof (for example, up to about 10 μm).

  Each column constituting the columnar crystal structure 88b is formed along the incident direction of the radiation 16, and a certain gap is secured between adjacent columns. The CsI: Na scintillator has a characteristic that the columnar crystal structure 88b is weak against humidity and the non-columnar crystal portion 90b is particularly vulnerable to humidity. Therefore, the CsI: Na scintillator is a light-transmitting moistureproof protective material 92b made of polyparaxylylene resin. It is sealed. And the tip part of the columnar crystal structure 88b and the common electrode 78a are in close contact with the scintillator sealed with the moisture-proof protective material 92b.

  Thus, the radiation detection which consists of the laminated structure of the 1st radiation conversion panel 28a containing the semiconductor layer 74a of a-Se, and the 2nd radiation conversion panel 28b containing the scintillator of the columnar crystal structure 88b of CsI: Na. 8, when radiation 16 is incident, first, the a-Se semiconductor layer 74a absorbs the low energy component of the radiation 16 and becomes a charge pair of a positive charge 94a and a negative charge 96a. Convert.

  The radiation 16 (high energy component) that has not been absorbed by the a-Se semiconductor layer 74a passes through the common electrode 78a and reaches the second radiation detection unit 72b.

  In the second radiation detection unit 72 b, the columnar crystal structure 88 b (the light emission portion 100) absorbs the high energy component of the radiation 16 and converts it into fluorescence 98. A part of the fluorescence 98 generated at the light emitting portion 100 (light in the sensitivity wavelength region of the photodiode 86b, for example, light in the long wavelength region of 500 nm or more) was formed substantially parallel to the incident direction of the radiation 16. The columnar crystal propagates linearly (goes straight) to the photodiode 86b, and the photodiode 86b converts a part of the fluorescence 98 into electric charge and accumulates it.

  In addition, another part of the fluorescence 98 generated at the light emitting portion 100 travels straight through the columnar crystal in the direction of the common electrode 78a, and passes through the common electrode 78a made of a transparent electrode such as ITO as transmitted light 102. The semiconductor layer 74a of a-Se is reached. If the transmitted light 102 is light in the sensitivity wavelength region of a-Se (for example, light in a short wavelength region of 500 nm or less), the semiconductor layer 74a absorbs the transmitted light 102 and has positive charges 94b and negative charges 96b. Convert to pair.

  The DC power supply 106 and the switch 108 of the voltage supply unit 42 are electrically connected to each pixel electrode 76a and the common electrode 78a. Here, when the switch 108 is turned on and a DC voltage is applied from the DC power source 106 such that each pixel electrode 76a has a positive polarity and the common electrode 78a has a negative polarity, a DC electric field is generated in the semiconductor layer 74a. According to this DC electric field, the positive charges 94a and 94b move to the negative common electrode 78a side, and the negative charges 96a and 96b move to the positive pixel electrode 76a side. As a result, the first charge detection unit 70a can take out the negative charges 96a and 96b through the pixel electrodes 76a. When the TFT 82a is turned on by the control signal from the drive circuit unit 30, the first charge detection unit 70a passes through the signal line 66a. Thus, an electrical signal corresponding to the negative charges 96a and 96b can be output to the readout circuit section 32.

  Further, when a DC voltage that causes an avalanche effect in the semiconductor layer 74a is applied between each pixel electrode 76a and the common electrode 78a, the positive charges 94a, 94b and Negative charges 96a and 96b are amplified. As a result, the number of charges taken out by the first charge detector 70a (the TFT 82a) via each pixel electrode 76a can be increased.

  In FIG. 8, a case where a DC voltage is applied so that each pixel electrode 76a has a positive polarity and the common electrode 78a has a negative polarity is illustrated. However, each pixel electrode 76a has a negative polarity and a common electrode 78a. Of course, the above effect can be obtained even when a positive DC voltage is applied.

  Further, in the above description, the case where the fluorescence 98 that goes straight through the columnar crystal structure 88b from the light emitting portion 100 toward the common electrode 78a passes through the common electrode 78a as it is and enters the semiconductor layer 74a as transmitted light 102 is described. did. Actually, part of the fluorescence 98 that goes straight toward the common electrode 78 a is reflected toward the second charge detection unit 70 b at the interface between the common electrode 78 a and the columnar crystal structure 88 b, and is reflected as the second light 104. The columnar crystal structure 88b goes straight toward the charge detection unit 70b and reaches the photodiode 86b. Therefore, the photodiode 86b can also convert the incident reflected light 104 into charges and store it.

  The common electrode 78a also functions as a dichroic filter that transmits the fluorescence 98 in the short wavelength region of 500 nm or less as the transmitted light 102 and reflects the fluorescence 98 in the long wavelength region longer than 500 nm as the reflected light 104. Good. Alternatively, a dichroic filter having such a function may be interposed between the common electrode 78a and the columnar crystal structure 88b.

  In the radiation imaging apparatus 10A according to the first embodiment, the direct conversion type first radiation conversion panel 28a (without synchronization with the irradiation timing of the radiation 16) regardless of the presence or absence of irradiation of the radiation 16 (of the radiation imaging apparatus 10A). It is possible to perform an electrical reset process on the semiconductor layer 74a) or the indirect conversion type second radiation conversion panel 28b (the photodiode 86b).

  In the radiation imaging apparatus 10A, the radiation 16 is unexpectedly output from the radiation output device 18 by not synchronizing with the irradiation timing of the radiation 16, and the radiation imaging of the subject 14 is suddenly performed. The electric reset process is not executed in the same time zone for the same region in the first radiation conversion panel 28a and the second radiation conversion panel 28b.

  That is, the timing and time zone when the electric reset process is performed on a predetermined region (region including a plurality of pixels 62a) in the first radiation conversion panel 28a, and the predetermined region in the second radiation conversion panel 28b. The timing and time zone when the electric reset process is executed for the region overlapping with the region (a region composed of a plurality of pixels 62b and in the same row or column as the pixel in the predetermined region) is shifted. ing.

  That is, in the first embodiment, the electrical reset process for all the pixels 62a and 62b of each radiation conversion panel 28a and 28b is not performed in a single reset process, but all the pixels 62a and 62b are one or more pixels 62a. , 62b is divided into a plurality of regions, and one electric reset process is executed for only one region in each of the radiation conversion panels 28a, 28b.

  Therefore, the electrical reset process for the plurality of regions of the radiation conversion panels 28a and 28b is performed at different times, and the electrical reset process for all the pixels 62a and 62b is completed by performing the electrical reset process a plurality of times. . Therefore, each time the number of electrical resets is repeated, the region where the electrical reset process is executed and the region where the electrical reset process is not executed are switched.

  The timing and time zone for executing the electrical reset processing for the plurality of regions are all determined and controlled by the reset control unit 45. Therefore, the reset control unit 45 does not overlap in time with respect to the same region between the two radiation conversion panels 28a and 28b in time, and the electrical reset with respect to a plurality of regions in the two radiation conversion panels 28a and 28b. By controlling the drive circuit unit 30 and the readout circuit unit 32 so that the processing is performed in different time zones, a desired electrical reset process is performed on each of the radiation conversion panels 28a and 28b. For this reason, the above-described electrical reset process is performed on the two radiation conversion panels 28a and 28b even during irradiation of the radiation 16 or during non-irradiation of the radiation 16.

  Next, the electrical reset process described above will be described more specifically with reference to FIG. FIG. 10 schematically illustrates the execution of an electrical reset process for the radiation conversion panels 28a and 28b.

  FIG. 10 illustrates an electrical reset process at a predetermined time. That is, the gate lines 64a and 64b indicated by bold lines indicate that a control signal indicating the start of the electrical reset process is supplied, and the hatched pixels 62a and 62b indicate pixels that are the target of the electrical reset process. ing.

  In this case, the reset control unit 45 applies the odd-numbered rows (first row and third row in FIG. 10) to the pixels 62a and the second radiation conversion panel 28b with respect to the first radiation conversion panel 28a in plan view. On the other hand, an electric reset process by line control is performed on the pixels 62b in even-numbered rows (second row in FIG. 10). That is, in the case of FIG. 10, the electrical reset process is executed by an interlace method in which one line is skipped so that the same line between the radiation conversion panels 28 a and 28 b is not the target of the electrical reset process.

  When the electrical reset processing for the odd-numbered pixels 62a of the first radiation conversion panel 28a and the even-numbered pixels 62b of the second radiation conversion panel 28b shown in FIG. The electric reset process is executed by line control on the even-numbered pixels 62a of the first radiation conversion panel 28a and the odd-numbered pixels 62b of the second radiation conversion panel 28b. Therefore, the electrical reset process for all the pixels 62a and 62b of the radiation conversion panels 28a and 28b is completed by performing the electrical reset process twice.

  7 to 9 show the states of the radiation conversion panels 28a and 28b during irradiation of the radiation 16 or when the radiation 16 is not irradiated.

  FIG. 7 illustrates a state of the radiation detector 28 when the radiation 16 is not irradiated.

  Here, when the electrical reset process is executed on the first radiation conversion panel 28a, the TFT 82a and the switch 120a may be turned on as described with reference to FIGS. As a result, charges accumulated in the semiconductor layer 74a (charges due to dark current) can be discharged to the ground via the TFT 82a, the switch 120a, and the operational amplifier 116a.

  Further, when the electrical reset process is performed on the second radiation conversion panel 28b, the TFT 82b and the switch 120b may be turned on as described with reference to FIG. Thereby, the charge accumulated in the photodiode 86b (charge due to dark current) can be discharged to the ground via the TFT 82b, the switch 120b, and the operational amplifier 116b.

  8 and 9 illustrate the state of the radiation detector 28 when the radiation 16 is irradiated.

  In FIG. 8, when the electrical reset process is executed on the first radiation conversion panel 28a, the TFT 82a and the switch 120a may be turned on. Thereby, charges accumulated in the semiconductor layer 74a (various charges including positive charges 94a and 94b and negative charges 96a and 96b) can be discharged to the ground via the TFT 82a, the switch 120a, and the operational amplifier 116a. At this time, since the electrical reset process is not performed on the second radiation conversion panel 28b, the photodiode 86b can convert the fluorescence 98 and the reflected light 104 into electric charges and store them. Therefore, the second radiation conversion panel 28b can output the charge as a charge signal corresponding to the radiation image.

  On the other hand, in FIG. 8, as in the case of FIG. 7, it is possible to execute the electrical reset process for the second radiation conversion panel 28b.

  In the time zone in which the electrical reset process is performed on the second radiation conversion panel 28b, the electrical reset process is not performed on the first radiation conversion panel 28a as described above. . Therefore, in the first radiation conversion panel 28a, the semiconductor layer 74a can convert the radiation 16 into positive charges 94a and negative charges 96a and store them. In addition, the radiation 16 can be converted into fluorescence 98 at the light emitting portion 100 of the columnar crystal structure 88b regardless of whether or not the electric reset process is performed on the second radiation conversion panel 28b. Therefore, the semiconductor layer 74a can also store the transmitted light 102 that has been transmitted through the common electrode 78a and incident on the semiconductor layer 74a into positive charges 94b and negative charges 96b. Accordingly, the first radiation conversion panel 28a can output the charges 96a and 96b as charge signals corresponding to the radiation image.

  In FIG. 9, when performing the electrical reset process on the first radiation conversion panel 28 a during irradiation of the radiation 16, the TFT 82 a and the switch 120 a are turned on, and the switch 108 of the voltage supply unit 42 is turned off. Yes. That is, even if positive charges 94a and 94b and negative charges 96a and 96b are generated in the semiconductor layer 74a during execution of the electrical reset process, these charges 94a, 94b, 96a and 96b are all released to the ground. The amplification operation of the charges 94a, 94b, 96a, 96b due to the avalanche effect in the semiconductor layer 74a is unnecessary. Therefore, power consumption may be reduced by turning off the switch 108 for the pixel 62a on which the electrical reset process is performed.

[Operation of First Embodiment]
Next, the operation of the radiation imaging system 12A including the radiation imaging apparatus 10A according to the first embodiment will be described.

  Here, the basic operation of the radiation imaging system 12A (for example, imaging of one radiation image (still image imaging)) will be described first, and then the characteristic operation (moving image imaging) of the first embodiment will be described. The control of reset processing in FIG. 11 will be described with reference to FIGS.

  First, the control processing unit 52 of the console 20 (see FIG. 1) acquires order information from the RIS 24 or the HIS 26, and stores the acquired order information in the order information storage unit 54.

  Next, the control processing unit 52 changes the imaging region of the subject 14 from the radiation output device 18 to the imaging region of the subject 14 based on the imaging region and imaging method of the subject 14 included in the order information and the information of the radiation imaging apparatus 10A and the radiation output device 18. Imaging conditions (tube voltage, tube current, exposure time) for irradiating the radiation 16 are set, and the set imaging conditions and order information are stored in the imaging condition storage unit 56.

  Next, the doctor or engineer inserts the radiation imaging apparatus 10A between the subject 14 and the imaging table, and then positions the imaging region of the subject 14 with respect to the radiation imaging apparatus 10A and the radiation output device 18.

  In this case, the radiation output device 18 requests the console 20 to transmit imaging conditions and the like, and the control processing unit 52 performs the imaging condition storage unit 56 based on the transmission request of the radiation output device 18 received via the communication unit 50. The radiographing conditions stored in is transmitted to the radiation output device 18 via the communication unit 50 by radio.

  On the other hand, if power is supplied from the battery 38 to the cassette control unit 34 and the communication unit 36 in the radiation imaging apparatus 10 </ b> A, the cassette control unit 34 transmits order information and the like to the console 20 via the communication unit 36. Request. Based on the transmission request of the cassette control unit 34 received via the communication unit 50, the control processing unit 52 wirelessly transmits the order information, the shooting conditions, and the instruction information stored in the shooting condition storage unit 56 via the communication unit 50. Transmit to the radiation imaging apparatus 10A. The cassette control unit 34 stores the order information, imaging conditions, and instruction information received via the communication unit 36 in the image memory 46 and / or the cassette ID memory 48.

  Further, a bias voltage is supplied from the bias power supply 40 to the photodiode 86b constituting each pixel 62b, so that each photodiode 86b uses the fluorescence 98 or reflected light 104 converted from the high energy component of the radiation 16 as a charge. It reaches the state where it can be converted and stored.

  Then, on the assumption that preparation for photographing such as positioning of the subject 14 is completed, the doctor or engineer turns on an exposure switch (not shown). Thereby, the control processing unit 52 captures the subject 14 by synchronizing the start of the output of the radiation 16 from the radiation output device 18 with the detection of the radiation 16 by the radiation detector 28 and the conversion to the radiation image. A synchronization control signal for executing radiography for the region is generated. The control processing unit 52 transmits the generated synchronization control signal to the radiation imaging apparatus 10 </ b> A and the radiation output apparatus 18 via the communication unit 50 by radio.

  Thus, when receiving the synchronization control signal, the radiation output device 18 irradiates the imaging region of the subject 14 with radiation 16 having a predetermined dose according to the imaging conditions.

  When the radiation 16 passes through the imaging region of the subject 14 and reaches the radiation detector 28 in the radiation imaging apparatus 10A, the a-Se semiconductor layer 74a absorbs the low energy component of the radiation 16 to absorb positive charges 94a and negative. A charge pair of charge 96a is generated. The high energy component of the radiation 16 that has not been absorbed by the semiconductor layer 74a reaches the second radiation detection unit 72b, and the columnar crystal structure 88b absorbs the high energy component of the radiation 16 and generates fluorescence 98.

  In this case, since the columnar crystal is formed along the vertical direction of FIGS. 7 to 9, a part of the fluorescence 98 generated at the light emitting portion 100 propagates through the columnar crystal toward the photodiode 86b (straightly traveling). The other part goes straight through the columnar crystal toward the common electrode 78a.

  A part of the fluorescence 98 that has traveled straight toward the common electrode 78 a passes through the common electrode 78 a as transmitted light 102 and enters the semiconductor layer 74 a, and another part as reflected light 104 toward the photodiode 86 b. The light is reflected and goes straight through the columnar crystal toward the photodiode 86b. Therefore, the photodiode 86b converts the incident fluorescence 98 and reflected light 104 into electric charges and accumulates them. Further, the semiconductor layer 74a absorbs the incident transmitted light 102 and generates a charge pair of a positive charge 94b and a negative charge 96b.

  Here, if a DC voltage is applied from the voltage supply unit 42 between each pixel electrode 76a and the common electrode 78a and a DC electric field is generated in the semiconductor layer 74a, the positive charges 94a and 94b and the negative charges 96a and 96b are In accordance with the direct current electric field, the pixel electrode 76a or the common electrode 78a is moved. If the DC voltage (DC electric field) is sufficient to generate the avalanche effect, the positive charges 94a and 94b and the negative charges 96a and 96b are amplified by the avalanche effect, and thus the first charge is passed through each pixel electrode 76a. The number of charges taken out by the charge detection unit 70a can be increased.

  Next, since the cassette control unit 34 receives the synchronization control signal via the communication unit 36, the address signal generation unit 44 supplies an address signal to the drive circuit unit 30, whereby each pixel 62 a in the accumulated state is received. , 62b, the charge information which is the radiation image of the subject 14 is read out.

  In this case, according to the address signal supplied from the address signal generation unit 44, the drive circuit unit 30 first passes through the two gate lines 64a and 64b connected to the pixels 62a and 62b in the first row. Control signals are supplied to the gates of the TFTs 82a and 82b of the pixels 62a and 62b in the first row, respectively.

  On the other hand, the readout circuit unit 32 converts the radiation image, which is the charge information held in the pixels 62a and 62b in the first row connected to the gate lines 64a and 64b selected by the drive circuit unit 30, into signal lines 66a, Read sequentially through 66b.

  The radiographic images read from the respective pixels 62a and 62b in the first row connected to the selected gate lines 64a and 64b are amplified by the charge amplifiers 110a and 110b of the read circuit unit 32, and then the A / D converter 112a. 112b are converted into digital signals. The radiographic image converted into the digital signal is temporarily stored in the image memory 46 of the cassette control unit 34.

  The drive circuit unit 30 sequentially performs such an operation on the pixels 62a and 62b in each row in accordance with the address signal supplied from the address signal generation unit 44. Thereby, the readout circuit unit 32 reads out the radiation image, which is the charge information held in the pixels 62a and 62b connected to the gate lines 64a and 64b, via the signal lines 66a and 66b, and the cassette control unit 34 image memories 46.

  In this way, the radiation image obtained by the irradiation of the radiation 16 from the radiation output device 18 is stored in the image memory 46.

  After storing the radiation image in the image memory 46, the image processing unit 47 of the cassette control unit 34 stores the two radiation images (first radiation image acquired from the first radiation conversion panel 28a) stored in the image memory 46. Then, addition processing is performed on the second radiation image acquired from the second radiation conversion panel 28b, and the radiation image (addition image) after the addition processing is also stored in the image memory 46. Then, the cassette control unit 34 stores each radiation image (first radiation image, second radiation image, addition image) stored in the image memory 46 and the cassette ID information stored in the cassette ID memory 48. The data is transmitted to the console 20 wirelessly via the communication unit 36.

  The control processing unit 52 of the console 20 stores each radiation image received via the communication unit 50 and the cassette ID information in the image memory 60 in association with each other. Then, the control processing unit 52 transmits the addition image stored in the image memory 60 to the display device 22 wirelessly via the communication unit 50 as an interpretation image that can be interpreted by a doctor according to the order information. The device 22 displays the received interpretation image.

  If a doctor or an engineer visually recognizes the interpretation image displayed on the display device 22 and obtains a desired radiographic image, the doctor or the engineer releases the subject 14 from the positioning state and ends the photographing with respect to the subject 14. On the other hand, if the interpretation image displayed on the display device 22 is not a desired radiation image, re-imaging is performed on the subject 14.

  When the image processing unit 47 of the cassette control unit 34 does not perform addition processing on the first radiation image and the second radiation image, the control processing unit 52 performs the first radiation on the image processing unit 58. Control is performed to generate an added image by performing an addition process of the image and the second radiation image.

  Next, characteristic operations of the first embodiment will be described with reference to FIGS. 11 and 12.

  As shown in FIGS. 11 and 12, this characteristic operation is that moving images can be acquired in all frames in moving image shooting (radiation shooting in which the subject 14 is repeatedly irradiated with radiation 16). In addition, for each frame, the regions (even-row pixels 62a and 62b and odd-row pixels 62a and 62b) in the radiation detector 28 (radiation conversion panels 28a and 28b) are alternately switched. Is.

  First, the example of FIG. 11 will be described.

  As shown in FIG. 11, in moving image shooting for the subject 14, radiation 16 is repeatedly irradiated (pulse irradiation) to the subject 14 at a predetermined cycle.

  In the odd-numbered pulse irradiation shown in FIG. 11 (first and third radiation irradiation in FIG. 11), the first radiation conversion panel 28a (panel 1) obtains a moving image with even-numbered pixels 62a, and On the other hand, in the second radiation conversion panel 28b (panel 2), the electric reset process is performed on the even-numbered pixels 62b and the odd-numbered pixels 62b. To get the video.

  Further, in the even-numbered pulse irradiation (second and fourth radiation irradiation in FIG. 11), the first radiation conversion panel 28a (panel 1) acquires a moving image with the odd-numbered pixels 62a and the even-numbered rows. On the other hand, in the second radiation conversion panel 28b (panel 2), an electrical reset process is performed on the odd-numbered pixels 62b and a moving image is generated on the even-numbered pixels 62b. Get a statue.

  In the time chart of FIG. 11, each pulse (pulse waveform indicated by a solid line) of panel 1 and panel 2 is in an accumulated state, that is, a state where a radiation image can be acquired. Further, the pulse indicated by the broken line is in a state in which a radiographic image cannot be acquired even if the radiation 16 is incident because the accumulated charge signal is discarded by executing the reset process during the irradiation of the radiation 16. This is illustrated.

  In the example of FIG. 11, as described above, in each frame, since the electrical reset process by the interlace method is performed on each radiation conversion panel 28a, 28b, the readout circuit unit 32 is provided with each radiation conversion panel 28a, 28b. If a charge signal is read out from the pixels 62a and 62b, a moving image is substantially acquired by the interlace method.

  That is, the moving image acquired by the odd-numbered pulse irradiation is a moving image (first radiation image) in which odd lines are missing for the first radiation conversion panel 28a, and for the second radiation conversion panel 28b. , A moving image (second radiation image) in which even-numbered rows are missing is obtained. In addition, the moving image acquired by even-numbered pulse irradiation is a moving image in which even-numbered rows are missing for the first radiation conversion panel 28a, and a moving image in which odd-numbered rows are missing for the second radiation conversion panel 28b. Become a statue.

  Therefore, the image processing unit 47 or the image processing unit 58 performs addition processing of the first radiation image and the second radiation image for each frame. In this case, of the two moving images, one moving image is a moving image in which even-numbered rows are missing, and the other moving image is a moving image in which odd-numbered rows are missing, but the two moving images are added. Thus, it is possible to obtain a moving image (addition image) having image information for all rows (areas). Therefore, it is possible to obtain an added image suitable for diagnostic interpretation by a doctor without performing special interpolation processing.

  In the example of FIG. 12, a moving image is acquired by the first radiation conversion panel 28a (panel 1) in odd-numbered pulse irradiation (first and third radiation irradiation in FIG. 12), and even-numbered pulse irradiation ( FIG. 12 illustrates a case where a moving image is acquired by the second radiation conversion panel 28b (panel 2) in the second and fourth radiation irradiations in FIG.

  In this case, in each of the radiation conversion panels 28a and 28b, a moving image acquisition region and an electric reset process are performed on the odd-numbered pixels 62a and 62b and the even-numbered pixels 62a and 62b for each frame in which the moving images are acquired. The area to be executed is switched alternately.

  That is, in FIG. 12, when a moving image is acquired by the first radiation conversion panel 28a by the first pulse irradiation, the first radiation conversion panel 28a acquires a moving image by the pixels 62a in the even rows, An electrical reset process is performed on the pixels 62a in the row.

  In addition, when a moving image is acquired by the second radiation conversion panel 28b by the second pulse irradiation, the second radiation conversion panel 28b acquires a moving image by the even-numbered pixels 62b and also the odd-numbered pixels 62b. An electrical reset process is executed on

  Further, when a moving image is acquired by the first radiation conversion panel 28a by the third pulse irradiation, the first radiation conversion panel 28a acquires a moving image by the odd-numbered pixels 62a and the even-numbered pixels 62a. An electrical reset process is executed on

  Furthermore, when a moving image is acquired by the second radiation conversion panel 28b by the fourth pulse irradiation, the second radiation conversion panel 28b acquires a moving image by the odd-numbered pixels 62b and also the pixels of the even-numbered rows. An electrical reset process is executed for 62b.

  As described above, in the example of FIG. 12, each of the radiation conversion panels 28a and 28b acquires an interlaced moving image in which odd or even rows are missing every two frames.

  Incidentally, since the radiation imaging apparatus 10A according to the first embodiment uses the two radiation conversion panels 28a and 28b, it is possible to acquire a high-quality moving image. Therefore, if the image processing unit 47 or the image processing unit 58 performs an interpolation process on a row that has been lost due to the electrical reset process on the acquired interlaced moving image, the image processing unit 47 or the image processing unit 58 has a high image quality without image loss. An added image can be obtained.

  In addition, the signal level of a moving image including a row that has been lost due to the electric reset process is higher than that of a moving image that has not been subjected to the electric reset process or an added image obtained by adding two moving images. Is small.

  Therefore, the reset control unit 45 sets the gain of the operational amplifier (the operational amplifier 116a or the operational amplifier 116b) that amplifies the charge signal of the moving image acquired by the pixel in the row where the reset process has not been performed higher than the gain in the normal time. The charge signal may be controlled to be amplified with a set gain. As a result, even if one moving image including a missing row is acquired in an arbitrary frame due to the electrical reset process, the signal level increases due to amplification, and thus the image processing unit 47 or the image processing unit 58 Image processing such as interpolation processing in can be easily performed.

  As described above, since moving images of the same radiation conversion panel are acquired every two frames, the image processing unit 47 or the image processing unit 58 may perform addition processing on the acquired moving images before and after. . Also in this case, as in the example of FIG. 11, one of the two moving images is a moving image in which even-numbered rows are missing, and the other moving image is a moving image in which odd-numbered rows are missing. Therefore, by adding two moving images, it is possible to obtain a moving image (added image) having image information for all rows (regions). Also in this case, it is possible to obtain an added image suitable for interpretation interpretation by a doctor without performing special interpolation processing.

  The example of FIG. 13 includes a first radiation conversion panel 28a for still image shooting having a large number of pixels (high pixel density) and a second radiation conversion panel for moving image shooting having a small number of pixels (low pixel density). The case where an electrical reset process is performed with respect to 28b is illustrated.

  In FIG. 13, unlike FIGS. 1 to 12, gate lines 64 a and 64 b extend in the column direction, and signal lines 66 a and 66 b extend in the row direction.

  As for the two radiation conversion panels 28a and 28b having different pixel densities as described above, the regions 132a, 132b, 134a and 134b overlapping between the two radiation conversion panels 28a and 28b are the same as those in FIGS. Similarly, electrical reset processing is not performed on the same region in the same time zone.

  That is, as shown in FIG. 13, the electrical reset process is performed on the region 134a of the first radiation conversion panel 28a and the region 134b of the second radiation conversion panel 28b that do not overlap each other at a certain time. Run. Then, after the electric reset process for these areas 134a and 134b is completed, the electric reset process may be executed for the areas 132a and 132b.

[Effect of the first embodiment]
As described above, according to the radiation imaging apparatus 10A according to the first embodiment, when radiation imaging is performed using the radiation conversion panels 28a and 28b, electricity to at least two regions in the radiation conversion panels 28a and 28b is obtained. The timing of the reset process is shifted, and the electric reset process is executed in different time zones. As described above, in the first embodiment, the reset control unit 45 controls the drive circuit unit 30 and the readout circuit unit 32 so that the time zones in which the electrical reset process is performed on at least two regions do not overlap each other. Thereby, it is possible to acquire a radiographic image in the other region while performing the electrical reset process on the one region. As a result, it is possible to avoid a state in which a radiographic image cannot be acquired due to the electrical reset process.

  In addition, since the reset control unit 45 switches the area where the electrical reset process is executed for each predetermined number of frames, a moving image in which only the area where the electrical reset process is executed is acquired in each frame. Since the area where the electric reset process is executed is switched every predetermined number of frames, the electric reset process is repeatedly executed only for a specific area, and a situation in which a moving image of the specific area cannot be obtained is avoided. be able to.

  That is, in the first embodiment, in one electrical reset process, the electrical reset process is not performed on the entire image area in the radiation conversion panels 28a and 28b, but only on a partial area. Since the process is executed, even if the frame rate of the moving image increases, it is possible to avoid the occurrence of a frame in which the entire image area is lost, and to reliably acquire the moving image in all the frames. Can do.

  Therefore, if a moving image is displayed on the display device 22, an operator who is performing a predetermined operation while viewing the moving image (for example, a doctor performing an operation of inserting a catheter into a patient while viewing the moving image). The work can be completed without interrupting the work.

  In addition, since the area where the electric reset process is executed is switched every predetermined number of frames, the missing area of the image in the moving image moves every predetermined number of frames.

  In addition, at least two areas described above each include one or more pixels 62a and 62b, and when a moving image of one frame is acquired, an electrical reset process is performed on one area. At the same time, a moving image is acquired in the other region.

  Furthermore, at least two regions are a region composed of pixels 62a and 62b of odd lines (odd rows and odd columns) and a plurality of pixels 62a and 62b arranged in a matrix, and even lines (odd rows and even rows). ) Of the pixels 62a and 62b. Therefore, for each frame, the reset control unit 45 performs electrical reset processing on the odd-line pixels 62a and 62b, obtains moving images at the even-line pixels 62a and 62b, and moves-images at the odd-line pixels 62a and 62b. It is also possible to control the drive circuit unit 30 and the readout circuit unit 32 so as to be switched alternately between the acquisition of the above and the electric reset processing for the pixels 62a and 62b of the even lines.

  The at least two regions are each composed of at least one line of pixels 62a and 62b among the plurality of pixels 62a and 62b arranged in a matrix, and are sequentially arranged along the direction intersecting each line. A plurality of regions 132a, 132b, 134a, 134b may be used. In this case, the reset control unit 45 resets the odd-numbered areas 132a, 132b, 134a, and 134b for each frame, acquires moving images in the even-numbered areas 132a, 132b, 134a, and 134b, The drive circuit unit 30 and the readout circuit unit 32 are controlled so as to be switched alternately between acquisition of moving images in the regions 132a, 132b, 134a, and 134b and reset processing for the even-numbered regions 132a, 132b, 134a, and 134b. It becomes possible to do.

  In any of these cases, it is possible to execute moving image acquisition from the pixels 62a and 62b in one region and electric reset processing for the pixels 62a and 62b in the other region by the interlace method. Become. In addition, in the case of moving image shooting, if any one of the processes is performed, the electric reset process for all the regions (all the pixels 62a and 62b) is completed with a predetermined number of shootings, so that the occurrence of afterimages is suppressed. Can be easily acquired.

  Further, if image signals corresponding to the moving images acquired by the two radiation conversion panels 28a and 28b are added by the image processing unit 47 or the image processing unit 58, there is no image missing region and a high-quality moving image (addition). Image). As a result, the operator can smoothly perform a predetermined operation while viewing the addition image displayed on the display device 22.

  Furthermore, in the first embodiment, the electric reset process for the same region of each radiation conversion panel 28a, 28b is performed at the same time in plan view between the first radiation conversion panel 28a and the second radiation conversion panel 28b. I don't want to run it. That is, even between the two radiation conversion panels 28a and 28b, the electrical reset process is performed at different time zones for the same region in plan view by shifting the timing of the electrical reset process. That is, the reset control unit 45 controls the drive circuit unit 30 and the readout circuit unit 32 so that the time zones for performing the electrical reset process on the same region do not overlap each other. In this way, it is possible to acquire a radiographic image in the region of the other radiation conversion panel while executing the electrical reset process on the region of one radiation conversion panel. Even in this case, it is possible to avoid a state in which the radiation image cannot be acquired in the same region as described above due to the electrical reset process.

  The interval between the electrical reset processes of the two radiation conversion panels 28a and 28b described with reference to FIGS. 11 to 13 is an example, and any radiation conversion panel having different characteristics such as the radiation conversion panels 28a and 28b may be used. Of course, the interval between the electrical reset processes may be appropriately adjusted according to the difference in the characteristics.

[Description of Second Embodiment]
Next, a radiation imaging apparatus 10B according to the second embodiment will be described with reference to FIGS. In the following description, the same reference numerals are assigned to the same components as those described above, and the detailed description thereof is omitted.

  As shown in FIG. 14, the radiation imaging system 12B including the radiation imaging apparatus 10B according to the second embodiment is configured so that the radiation detector 28 included in the radiation imaging apparatus 10B includes one radiation conversion panel. Different from the imaging system 12A. Accordingly, the one radiation conversion panel may be a direct conversion type radiation conversion panel or an indirect conversion type radiation conversion panel, but in FIG. 14, an indirect conversion type radiation conversion panel is used. Some cases are illustrated. Therefore, in FIG. 14, the voltage supply unit 42 does not exist.

  In the radiation imaging apparatus 10A according to the first embodiment, the case where there are two radiation conversion panels 28a and 28b has been described. However, in the second embodiment, since there is only one radiation conversion panel, the radiation described above is used. When the reference numerals “a” and “b” are omitted in the description of each component of the imaging apparatus 10A, each component of the radiation imaging apparatus 10B of the second embodiment is described. Therefore, in the second embodiment, description of each component in the radiation imaging apparatus 10B is omitted.

  In the second embodiment, since there is only one radiation conversion panel (radiation detector 28) as described above, for example, an electrical reset process is performed on the pixels 62 in the odd-numbered rows as shown in FIG. Then, as shown in FIG. 15B, the electrical reset process is executed for the pixels 62 in the even-numbered rows.

  When the irradiation of the radiation 16 on the subject 14 is pulse irradiation, as shown in FIG. 16, for example, in an odd-numbered frame, a moving image is acquired with an even-numbered pixel 62 and an odd-numbered pixel. The electric reset process is performed on the pixels 62, and in the even-numbered frame, a moving image is acquired with the pixels 62 on the odd-numbered rows and the electric reset process is performed on the pixels 62 on the even-numbered rows. It should be noted that, if the image processing unit 47 or the image processing unit 58 adds the moving images of two frames that move back and forth in time, it is a matter of course that a high-quality added image without image omission can be obtained.

  Thus, even in the radiation imaging apparatus 10B according to the second embodiment provided with the radiation detector 28 having one radiation conversion panel, if the electric reset process is performed by the interlace method, the electricity in the first embodiment is obtained. Each effect obtained by the reset process can be easily achieved.

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

10A, 10B ... Radiation imaging devices 12A, 12B ... Radiation imaging system 14 ... Subject 16 ... Radiation 18 ... Radiation output device 20 ... Console 22 ... Display device 28 ... Radiation detector 28a ... First radiation conversion panel 28b ... Second Radiation conversion panel 30 ... drive circuit unit 32 ... readout circuit unit 34 ... cassette control unit 40 ... bias power supply 44 ... address signal generation unit 45 ... reset control units 47, 58 ... image processing units 62, 62a, 62b ... pixel 70a ... first 1 electric charge detection part 70b ... 2nd electric charge detection part 72a ... 1st radiation detection part 72b ... 2nd radiation detection part 82a, 82b ... TFT
86b ... Photodiodes 94a, 94b ... Positive charges 96a, 96b ... Negative charges 98 ... Fluorescence 102 ... Transmitted light 104 ... Reflected light 110a, 110b ... Charge amplifiers 112a, 112b ... A / D converters 116a, 116b ... Operational amplifiers 118a, 118b ... Capacitors 120a, 120b ... Switches 132a, 132b, 134a, 134b ... area

Claims (10)

At least one radiation conversion panel capable of converting radiation into a radiation image;
A reset processing unit capable of executing a reset process for suppressing the occurrence of an afterimage for the radiation conversion panel;
A reset control unit for controlling the reset processing unit so as to execute the reset processing for at least two regions in the radiation conversion panel in different time zones;
A radiation imaging apparatus comprising: The apparatus of claim 1.
When the moving image as the radiation image is acquired by repeatedly performing the irradiation of the radiation, the reset control unit performs the reset processing so as to switch an area in which the reset processing is executed every predetermined number of frames. The radiation imaging apparatus characterized by controlling a part. The apparatus of claim 2.
The radiation conversion panel has a plurality of pixels arranged in a matrix for converting and storing the radiation into electric charges,
Each of the at least two regions includes one or more pixels, and
The radiographic apparatus according to claim 1, wherein when a moving image of one frame is acquired, the reset process is performed on one area and the moving image is acquired on the other area. The apparatus of claim 3.
The at least two regions are a region composed of pixels of odd lines and a region composed of pixels of even lines among the plurality of pixels arranged in a matrix.
The reset control unit performs reset processing on the odd-line pixels and acquisition of moving images with the even-line pixels and acquisition of moving images with pixels on the odd-line and the even-line pixels for each frame. The radiation imaging apparatus characterized by controlling the said reset process part so that it may switch alternately with a reset process. The apparatus of claim 3.
The at least two regions are each composed of at least one line of the plurality of pixels arranged in a matrix, and a plurality of regions sequentially arranged along a direction intersecting each line. Yes,
The reset control unit, for each frame, reset processing for odd-numbered areas, acquisition of moving images in even-numbered areas, acquisition of moving images in odd-numbered areas, and reset processing for even-numbered areas In addition, the radiographic apparatus is characterized in that the reset processing unit is controlled so as to be switched alternately. In the apparatus of any one of Claims 2-5,
A radiation imaging apparatus comprising: an image processing unit provided in the radiation imaging apparatus; or an external image processing apparatus that adds image signals corresponding to moving images of two frames before and after. In the apparatus of any one of Claims 1-6,
A first radiation conversion panel and a second radiation conversion panel are sequentially laminated along the incident direction of the radiation,
The radiographic imaging apparatus, wherein the reset control unit controls the reset processing unit so that the reset processing for the same region of each radiation conversion panel in a plan view is not executed in the same time zone. The apparatus of claim 7.
Each of the radiation conversion panels has a plurality of pixels arranged in a matrix for converting and storing the radiation into electric charges,
The radiation imaging apparatus, wherein a pixel density of the first radiation conversion panel and a pixel density of the second radiation conversion panel are different from each other. The device according to claim 7 or 8,
By an image processing unit provided in the radiation imaging apparatus or an external image processing apparatus,
A radiation imaging apparatus, wherein image signals corresponding to radiation images acquired by the first radiation conversion panel and the second radiation conversion panel are added. In the apparatus of any one of Claims 3-5 and 8,
The reset processing unit includes a drive circuit unit that switches the pixels to an accumulation state in which the charge can be accumulated or a read state in which the accumulated charge can be read, and a readout circuit that reads out the charge from the pixel in the readout state And
The drive circuit unit switches each pixel to the readout state, and the readout circuit unit reads out the electric charge accumulated in each pixel and discharges it to the ground, whereby the reset process for each pixel is executed. A characteristic radiographic apparatus.

Images