Radiation imaging apparatus, control method thereof, and program

Abstract

To provide a mechanism capable of performing efficient radiation imaging by stabilizing the imaging time of radiation imaging.SOLUTION: A radiation imaging apparatus 100 includes: a pixel array IR having a plurality of pixels including an imaging pixel 101 that acquires an electrical signal related to a radiation image and a detection pixel 104 that detects a dose of a radiation ray based on the electrical signal; a control unit 180 that performs control to transmit a stop request signal for stopping irradiation of a radiation ray in a radiation generation apparatus to a control apparatus based on the dose of a radiation ray detected by the detection pixel 104 and performs irradiation stop determination in which the irradiation of the radiation ray is stopped; and a readout circuit 160 that reads out the electrical signal related to the radiation image from the imaging pixel 101 in a case where the irradiation stop determination is performed in the control unit 180.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radiation imaging apparatus, a control method thereof, and a program. [Background technology]

[0002] Conventionally, a radiation imaging device having an automatic exposure control (AEC) function has been known as one type of radiation imaging device. This radiation imaging device with the AEC function measures the radiation dose during radiation irradiation and can stop the radiation irradiation based on the measurement result. For example, this radiation imaging device with the AEC function monitors the radiation dose by operating only detection pixels set for detecting the radiation dose at high speed during radiation irradiation, out of a pixel array having a plurality of pixels.

[0003] As an example of such a radiation imaging device, Patent Document 1 describes a radiation imaging device that includes a dose detection unit that detects the dose of radiation reaching the imaging region within the imaging region of the radiation imaging device. Specifically, Patent Document 1 predicts the timing at which radiation irradiation should be stopped in the radiation generating device based on the dose detected by the dose detection unit and a preset dose target value. Patent Document 1 also transmits a stop timing notification to the radiation generating device to inform it of the timing to stop radiation irradiation a predetermined time before the arrival of the stop timing, taking communication delay time into consideration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-138829 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, the communication delay time is a value that varies from time to time due to the influence of the communication environment, etc., and therefore the timing at which radiation irradiation actually stops may differ from the timing at which radiation irradiation should be stopped. In this case, the imaging time for radiation imaging is not stable, which poses a problem in that efficient radiation imaging cannot be performed.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a mechanism for stabilizing the imaging time of radiation imaging and enabling efficient radiation imaging. [Means for solving the problem]

[0007] The radiation imaging device of the present invention is a radiation imaging device configured to be able to communicate with a control device that controls a radiation generation device that irradiates radiation, and includes a pixel array having a plurality of pixels that acquire electrical signals in response to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signals related to a radiation image and detection pixels that detect the radiation dose based on the electrical signals; control means that controls the transmission of a stop request signal to the control device to stop the irradiation of the radiation generation device based on the radiation dose detected by the detection pixels, and that makes an irradiation stop determination that the irradiation of the radiation has stopped; and readout means that, when the irradiation stop determination is made by the control means, reads out the electrical signals related to the radiation image from the imaging pixels. [Effects of the Invention]

[0008] According to the present invention, it is possible to stabilize the imaging time of radiography, and to perform radiography efficiently. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a radiation imaging apparatus according to an embodiment of the present invention. [Figure 2]2 is a diagram illustrating a detailed example of the circuit configuration of an amplifier unit illustrated in FIG. 1. FIG. [Figure 3] 2 is a plan view showing an example of a schematic configuration of imaging pixels, detection pixels, and correction pixels included in a pixel array region (imaging region) of the radiation imaging device shown in FIG. [Figure 4] 4 is a cross-sectional view of an imaging pixel taken along line AA' in FIG. 3, and a cross-sectional view of a correction pixel taken along line BB' in FIG. 3. [Figure 5] 1 is a diagram showing an example of a schematic configuration of a radiation imaging system including a radiation imaging apparatus according to an embodiment of the present invention. [Figure 6] 1 is a timing chart showing an example of the operation of a radiation imaging system including a radiation imaging apparatus according to an embodiment of the present invention. [Figure 7] 10 is a flowchart illustrating an example of a processing procedure in a control method for a radiation imaging apparatus according to an embodiment of the present invention. [Figure 8] 2 shows an embodiment of the present invention and is a diagram for explaining a case where the control unit in FIG. 1 determines whether to stop irradiation of radiation based on an electrical signal (detection pixel signal) acquired from a detection pixel. FIG. [Figure 9] 2 is a diagram illustrating an embodiment of the present invention, illustrating a case where the control unit in FIG. 1 determines whether to stop irradiation of radiation based on an integrated irradiation dose of radiation acquired from a detection pixel. FIG. [Figure 10] 10A and 10B are diagrams for explaining a case where detection of the start and end of radiation irradiation and control of an irradiation stop request signal are performed and radiation irradiation stop determination is made in a radiation imaging apparatus according to an embodiment of the present invention. [Figure 11] FIG. 2 is a diagram showing an example of a radiation measurement field arranged in a radiation imaging apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments of the present invention described below do not limit the scope of the claims, and not all of the combinations of features described in the embodiments of the present invention are necessarily essential to the means for solving the problems of the present invention.

[0011] 1 is a diagram showing an example of a schematic configuration of a radiation imaging apparatus 100 according to an embodiment of the present invention. As shown in FIG. 1, the radiation imaging apparatus 100 includes a pixel array region (imaging region) IR, a power supply circuit 140, a drive circuit 150, a readout circuit 160, a signal processing unit 170, a control unit 180, and a communication unit 190.

[0012] The pixel array region (imaging region) IR is a region in which a plurality of pixels that acquire electrical signals in response to incident radiation are arranged in a plurality of rows and a plurality of columns. The pixel array region (imaging region) IR includes a plurality of imaging pixels 101 that acquire electrical signals related to a radiographic image, a plurality of detection pixels 104 that detect the radiation exposure dose based on the electrical signals, and a plurality of correction pixels 107 that correct the radiation exposure dose. The pixel array region (imaging region) IR also includes a plurality of drive lines 110 (including detection drive lines 111), a plurality of signal lines 120, and a plurality of bias lines 130.

[0013] The drive lines 110 are arranged corresponding to the rows in the pixel array region (imaging region) IR, and each drive line 110 corresponds to one of the pixel rows. The signal lines 120 are arranged corresponding to the columns in the pixel array region (imaging region) IR, and each signal line 120 corresponds to one of the pixel columns.

[0014] Each imaging pixel 101 includes a conversion element 102 that converts incident radiation into an electrical signal related to a radiographic image, and a switch element 103 that connects the conversion element 102 to a corresponding signal line 120. Each detection pixel 104 includes a conversion element 105 that converts incident radiation into an electrical signal related to a radiation exposure dose, and a switch element 106 that connects the conversion element 105 to a corresponding signal line 120. Each correction pixel 107 includes a conversion element 108 that converts incident radiation into an electrical signal for correcting the radiation exposure dose, and a switch element 109 that connects the conversion element 108 to a corresponding signal line 120. In this case, the sensitivity of the correction pixel 107 to radiation is lower than the sensitivity of the detection pixel 104 to radiation. The detection pixel 104 and the correction pixel 107 are arranged so as to be included in a row and a column formed by a plurality of imaging pixels 101. In FIG. 1, the imaging pixels 101, the detection pixels 104, and the correction pixels 107 are distinguished from one another by applying different hatching to the conversion elements 102, the conversion elements 105, and the conversion elements 108.

[0015] The conversion elements 102, 105, and 108 may each be configured with a scintillator that converts incident radiation into light and a photoelectric conversion element that converts the light generated by the scintillator into an electrical signal. In this case, the scintillator is generally formed in a sheet shape so as to cover the pixel array region (imaging region) IR, and is shared by multiple pixels. Note that the conversion elements 102, 105, and 108 may each be configured with a conversion element that directly converts incident radiation into an electrical signal, instead of the configuration of the scintillator and photoelectric conversion element described here.

[0016] The switch element 103, the switch element 106, and the switch element 109 may be configured to include a thin film transistor (TFT) having an active region made of a semiconductor material such as amorphous silicon or polycrystalline silicon.

[0017] The first electrodes of the conversion elements 102 are connected to the first main electrodes of the switch elements 103, and the second electrodes of the conversion elements 102 are connected to a bias line 130. One bias line 130 extends in the column direction and is commonly connected to the second electrodes of the multiple conversion elements 102 arranged in the column direction. The bias line 130 receives a bias voltage Vs from a power supply circuit 140. The second main electrodes of the switch elements 103 of one or more imaging pixels 101 included in one column are connected to one signal line 120. The control electrodes of the switch elements 103 of one or more imaging pixels 101 included in one row are connected to one drive line 110.

[0018] The detection pixels 104 and the correction pixels 107 also have the same pixel configuration as the imaging pixels 101, and are connected to corresponding drive lines 110, corresponding signal lines 120, and corresponding bias lines 130. The detection pixels 104 and the correction pixels 107 are exclusively connected to the signal lines 120. That is, the correction pixel 107 is not connected to the signal line 120 to which the detection pixel 104 is connected. Similarly, the detection pixel 104 is not connected to the signal line 120 to which the correction pixel 107 is connected. The imaging pixel 101 may be connected to the same signal line 120 as the detection pixel 104 or the correction pixel 107.

[0019] The power supply circuit 140 supplies the bias voltage Vs to the bias line 130 under the control of the control unit 180 .

[0020] The drive circuit 150 is configured to supply drive signals to pixels to be driven through multiple drive lines 110 under the control of the control unit 180. In this embodiment, the drive signals are signals for turning on switch elements included in the pixels to be driven. The switch elements of each pixel are turned on by a high-level signal and turned off by a low-level signal. Therefore, this high-level signal is called a drive signal. When the drive signal is supplied to a pixel, the electrical signal (charge) accumulated in the conversion element of that pixel becomes readable by the readout circuit 160. Note that in this embodiment, when a drive line 110 is connected to at least one of the detection pixel 104 and the correction pixel 107, that drive line 110 is called a detection drive line 111.

[0021] The readout circuit 160 is configured to read out electrical signals (charges) from the plurality of pixels through the plurality of signal lines 120 under the control of the control unit 180. In this embodiment, the readout circuit 160 performs readout settings for the electrical signals acquired by the plurality of pixels before reading out the electrical signals related to a radiographic image from the imaging pixels 101. As shown in FIG. 1 , the readout circuit 160 is configured to include a plurality of amplifiers 161, a multiplexer 162, and an analog-to-digital converter (AD converter (ADC)) 163. Each of the plurality of signal lines 120 is connected to a corresponding one of the plurality of amplifiers 161 in the readout circuit 160. One signal line 120 corresponds to one amplifier 161. The multiplexer 162 selects the plurality of amplifiers 161 in a predetermined order and supplies the electrical signal from the selected amplifier 161 to the AD converter 163. The AD converter 163 converts the analog electrical signal supplied from the multiplexer 162 into a digital electrical signal and outputs it.

[0022] The electrical signals read out from the imaging pixels 101 by the readout circuit 160 are supplied to the signal processing unit 170, where they are subjected to processing such as calculation and storage. Specifically, the signal processing unit 170 includes a calculation unit 171 and a storage unit 172 as shown in FIG. 1 , and the calculation unit 171 generates a radiographic image based on the electrical signals read out from the imaging pixels 101 and supplies the radiographic image to the control unit 180.

[0023] Furthermore, the electrical signals read out from the detection pixels 104 and the correction pixels 107 in the readout circuit 160 are supplied to the signal processing unit 170, and are subjected to processing such as calculation and storage by the calculation unit 171. Specifically, the signal processing unit 170 outputs information indicating radiation irradiation to the radiation imaging device 100 (specifically, the pixel array region (imaging region) IR) based on the electrical signals read out from the detection pixels 104 and the correction pixels 107. For example, the signal processing unit 170 outputs, as information indicating radiation irradiation, detection information on radiation irradiation to the radiation imaging device 100 (specifically, the pixel array region (imaging region) IR) and information on the radiation exposure dose and / or cumulative exposure dose.

[0024] The control unit 180 controls the drive circuit 150 and the readout circuit 160, for example, based on information indicating irradiation of radiation from the signal processing unit 170. The control unit 180 controls, for example, the start and end of exposure (accumulation of charges (electrical signals) corresponding to incident radiation by the imaging pixels 101) based on the information indicating irradiation of radiation from the signal processing unit 170. The control unit 180 may be configured with a general-purpose processing circuit such as a microprocessor, or may be configured with a dedicated processing circuit such as an ASIC (Application Specific Integrated Circuit). Furthermore, when the control unit 180 is configured with a general-purpose processing circuit, the control unit 180 may further include a memory.

[0025] In order to detect the radiation exposure dose, the control unit 180 controls the drive circuit 150 to scan only the detection drive lines 111 and set a state in which only the electrical signals from the detection pixels 104 and the correction pixels 107 can be read out. Next, the control unit 180 controls the readout circuit 160 to read out the electrical signals from the columns corresponding to the detection pixels 104 and the correction pixels 107, and detects the radiation exposure dose based on these electrical signals. Through this operation, the control unit 180 of the radiation imaging device 100 can detect the radiation exposure dose during radiation irradiation based on the electrical signals acquired by the detection pixels 104. For example, the control unit 180 may calculate the radiation exposure dose detected by the detection pixels 104 from any one of the average value, integrated value, and differential value of the electrical signals acquired by the detection pixels 104.

[0026] The communication unit 190 is controlled by the control unit 180 and has a function of communicating between the radiation imaging apparatus 100 and an external device. In this case, the communication by the communication unit 190 may use a desired method or standard of communication, such as wired communication or wireless communication, and is not limited to a specific communication standard. Furthermore, the radiation imaging apparatus 100 may be equipped with multiple communication units 190 in order to support multiple communication standards.

[0027] Fig. 2 is a diagram showing a detailed example of the circuit configuration of the amplifier unit 161 shown in Fig. 1. In Fig. 2, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and their description will be omitted.

[0028] As shown in FIG. 2, the amplifier unit 161 includes a differential amplifier circuit AMP and a sample-and-hold circuit SH. The differential amplifier circuit AMP amplifies and outputs an electrical signal appearing on the signal line 120. The control unit 180 can reset the potential of the signal line 120 by supplying a signal φR to the switch element of the differential amplifier circuit AMP. The output from the differential amplifier circuit AMP can be held by the sample-and-hold circuit SH. The control unit 180 causes the sample-and-hold circuit SH to hold the electrical signal by supplying a signal φSH to the switch element of the sample-and-hold circuit SH. The electrical signal held in the sample-and-hold circuit SH is read out by the multiplexer 162.

[0029] Fig. 3 is a plan view showing an example of a schematic configuration of the imaging pixels 101, detection pixels 104, and correction pixels 107 included in the pixel array region (imaging region) IR of the radiation imaging device 100 shown in Fig. 1. In Fig. 3, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The plane of the plan view shown in Fig. 3 is equivalent to an orthogonal projection onto a plane parallel to the pixel array region (imaging region) IR of the radiation imaging device 100. As indicated by hatching in Fig. 3, a metal layer is disposed above the conversion element 108 of the correction pixel 107, and this metal layer shields the conversion element 108 from light.

[0030] Fig. 4 is a cross-sectional view of the imaging pixel 101 taken along line A-A' in Fig. 3, and a cross-sectional view of the correction pixel 107 taken along line B-B' in Fig. 3. Specifically, in Fig. 4, Fig. 4(a) is a cross-sectional view of the imaging pixel 101 taken along line A-A' in Fig. 3, and Fig. 4(b) is a cross-sectional view of the correction pixel 107 taken along line B-B' in Fig. 3. In Figs. 4(a) and 4(b), components similar to those shown in Figs. 1 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0031] As described above, FIG. 4(a) is a cross-sectional view of the imaging pixel 101 taken along line A-A' in FIG. 3. The cross-sectional view of the detection pixel 104 is similar to the cross-sectional view of the imaging pixel 101 shown in FIG. 4(a). As shown in FIG. 4(a), the imaging pixel 101 includes a switch element 103 disposed above an insulating support substrate 400 such as a glass substrate. The switch element 103 may be a TFT (thin film transistor). An interlayer insulating layer 401 is disposed above the switch element 103. A conversion element 102 is disposed above the interlayer insulating layer 401. The conversion element 102 is a photoelectric conversion element capable of converting light into an electrical signal. As shown in FIG. 4(a), the conversion element 102 includes, for example, an electrode 402, a PIN photodiode 403, and an electrode 404. The conversion element 102 may be configured using an MIS sensor instead of a PIN photodiode. Furthermore, a protective film 405, an interlayer insulating layer 406, a bias line 130, and a protective film 407 are arranged in this order above the conversion element 102. Furthermore, a planarizing film and a scintillator (not shown) are arranged above the protective film 407. The electrode 404 is connected to the bias line 130 via a contact hole. For example, ITO, which has optical transparency, is used as the material for the electrode 404, and it is possible for light converted from radiation by the scintillator (not shown) to pass through the material.

[0032] As described above, FIG. 4(b) is a cross-sectional view of the correction pixel 107 taken along line B-B' in FIG. 3. As shown in FIG. 4(b), the correction pixel 107 differs from the imaging pixel 101 and the detection pixel 104 in that the conversion element 108 is covered by a light-shielding member 408, but may be the same as the imaging pixel 101 and the detection pixel 104 in other respects. The light-shielding member 408 is formed, for example, from the same metal layer as the bias line 130. Because the conversion element 108 of the correction pixel 107 is covered by the light-shielding member 408, the sensitivity of the correction pixel 107 to radiation is significantly lower than the sensitivity of the imaging pixel 101 and the detection pixel 104 to radiation. It can also be said that the charge (electrical signal) accumulated in the conversion element 108 of the correction pixel 107 is not caused by radiation.

[0033] Fig. 5 is a diagram showing an example of a schematic configuration of a radiation imaging system 500 including a radiation imaging apparatus 100 according to an embodiment of the present invention. In Fig. 5, components that are the same as those shown in Fig. 1 are given the same reference numerals, and detailed description thereof will be omitted. As shown in Fig. 5, the radiation imaging system 500 includes the radiation imaging apparatus 100, a radiation generation apparatus 510, an information processing apparatus 520, an access point 530, a communication device 540, a synchronization control device 550, a status notification device 560, and an in-hospital LAN 570.

[0034] The radiation imaging device 100 captures a radiation image based on incident radiation 511 (including radiation 511 that has passed through the subject H). The radiation 511 incident on the radiation imaging device 100 is converted into electric charges, which are electrical signals, and further processed as radiation image data and transmitted to the information processing device 520 (wirelessly transmitted in the example shown in FIG. 5).

[0035] The radiation generating device 510 irradiates radiation 511 toward a subject H, such as a patient, and the radiation imaging device 100 under the control of the synchronization control device 550 and the information processing device 520. The radiation generating device 510 has, for example, a radiation tube that accelerates electrons with a high voltage and causes them to collide with an anode in order to generate radiation 511 such as X-rays. Note that, although X-rays are typically used as the radiation 511, α-rays, β-rays, γ-rays, or neutron rays may also be used.

[0036] The information processing device 520 is a control device realized by known technology such as a general-purpose computer, and includes an input unit 521, a control unit 522, a storage unit 523, and a display unit 524. The information processing device 520 performs, for example, image processing for correction, storage, and display of radiation image data received from the radiation imaging device 100. At this time, some or all of the image processing functions may be performed by the radiation imaging device 100. The information processing device 520 also displays a radiation image for the operator S and gives instructions for radiation imaging via the display unit 524. The information processing device 520 also has a function that allows the operator S to input, via the input unit 521, instructions regarding imaging conditions for the subject H and irradiation conditions of radiation 511, and an irradiation field, which is an area in the radiation imaging device 100 where the irradiation dose of radiation 511 is detected. For example, before radiation imaging, the input imaging information such as the imaging conditions, irradiation conditions (including irradiation time), and irradiation field is transmitted to the radiation imaging device 100 and set therein. In addition, the control unit 522 of the information processing device 520 has the functions of comparing the acquired exposure dose of radiation 511 with a threshold value, responding to a connection request, and transmitting information for wireless communication such as wireless information.

[0037] The access point 530 is a device that relays radio waves for wirelessly exchanging information between the radiation imaging apparatus 100 and the information processing device 520. At this time, the radiation imaging apparatus 100 performs wireless communication by having the internal control unit 180 control the communication unit 190. Note that, although the access point 530 is connected to the information processing device 520 via the synchronization control device 550 in FIG. 5, it may also be directly connected to the information processing device 520.

[0038] The communication device 540 is connected to the information processing device 520 and is a device that transmits and receives radio waves for wireless short-range communication between the radiation imaging apparatus 100 and the information processing device 520. For example, the communication device 540 is a dongle connected to the information processing device 520 via a USB (Universal Serial Bus) interface. The communication device 540 is a device that complies with at least one of the Bluetooth (registered trademark) Basic Rate / Enhanced Data Rate (BR / EDR) standard and the Bluetooth Low Energy (BLE) standard. The communication device 540 may also be an RFID (radio frequency IDentifier) ​​device that exchanges information from a tag embedded with ID information via short-range wireless communication using an electromagnetic field, radio waves, or the like. In this case, the RFID communication method may be either an electromagnetic induction method or a radio wave method. The communication device 540 may also have the functionality of the access point 530.

[0039] 5 shows an example in which the communication device 540 is connected to the information processing device 520, but the present embodiment is not limited to this. The communication device 540 may be connected to another external device constituting the radiation imaging system 500, such as the radiation generation device 510. Furthermore, the communication device 540 may be substituted by equipment that is pre-installed in the radiation imaging system 500.

[0040] The synchronization control device 550 has a circuit that mediates communication and monitors the states of the radiation imaging apparatus 100 and the radiation generation apparatus 510. For example, the synchronization control device 550 controls the irradiation of radiation 511 from the radiation generation apparatus 510 and controls the radiation imaging of the subject H by the radiation imaging apparatus 100. The synchronization control device 550 may also include a built-in hub that connects multiple network devices.

[0041] The status notification device 560 is connected to the information processing device 520 as a notification means for the operator S. The status notification device 560 notifies the operator S of the current status of the radiation imaging apparatus 100 or the completion of a specific process based on information about the radiation imaging apparatus 100 received from the radiation imaging apparatus 100 via the access point 530 or received from the communication device 540. The status notification device 560 uses a light-emitting element such as an LED, and notifies the operator S by associating a plurality of lighting patterns with the current status of the radiation imaging apparatus 100 in advance. The status notification device 560 may also use a sound source such as a speaker. In this case, a buzzer sound pattern is associated with the current status of the radiation imaging apparatus 100 in advance, and notifies the operator S. The status notification device 560 may also use a combination of the above-mentioned notification by a light-emitting element such as an LED and notification by a sound source such as a speaker. Although FIG. 5 shows an example in which the status notification device 560 is connected to the information processing device 520, it may be replaced by devices such as the display unit 524 and speaker provided in the information processing device 520.

[0042] The hospital LAN 570 is a local area network established within the hospital, and has the function of transmitting and receiving radiation image data captured by the radiation imaging system 500 to and from various locations within the hospital.

[0043] The radiation imaging system 500 can perform radiation imaging of the subject H using synchronous imaging and asynchronous imaging. Here, synchronous imaging is an imaging method in which the timing of the irradiation of radiation 511 and radiation imaging is synchronized by exchanging an electrical synchronization signal between the radiation imaging apparatus 100 and the radiation generation apparatus 510 via a synchronization control device 550. On the other hand, asynchronous imaging is an imaging method in which the radiation imaging apparatus 100 starts radiation imaging by detecting the incidence of radiation 511, without exchanging an electrical synchronization signal between the radiation imaging apparatus 100 and the radiation generation apparatus 510. In this asynchronous imaging, the radiation imaging apparatus 100 may transfer radiation images to an external device for each radiation imaging, or may store the radiation images internally in the radiation imaging apparatus 100 without transferring them for each radiation imaging.

[0044] 5 can perform imaging under imaging conditions commonly used in radiation imaging, such as fluoroscopic imaging, continuous imaging, still image imaging, DSA imaging, roadmap imaging, programmed imaging, tomography, and tomosynthesis imaging. The imaging frame rate, the tube voltage and tube current of the radiation tube of the radiation generator 510, the readout area and drive binning settings of the pixel array region (imaging region) IR, and the collimator aperture settings can be configured in the radiation imaging system 500. The window width of the radiation 511, whether or not to store radiation images in the radiation imaging device 100, and the like can also be configured in the radiation imaging system 500. Furthermore, the radiation imaging system 500 can also be configured with functions such as automatic dose control (ADC) and automatic exposure control (AEC).

[0045] Furthermore, the information processing device 520 receives input, via the input unit 521, information such as the dose of radiation 511, the upper limit irradiation time (ms), the tube current (mA), the tube voltage (kV), and the region of interest (ROI), which is an area where the radiation 511 should be monitored. When the operator S operates an exposure switch attached to the radiation generation device 510, the information processing device 520 transmits a start request signal to the radiation imaging device 100. This start request signal is a signal requesting the start of irradiation of the radiation 511. In response to receiving the start request signal, the radiation imaging device 100 begins preparations for receiving irradiation of the radiation 511. When preparations are complete, the radiation imaging device 100 transmits a start possible signal to the radiation generation device 510 via the access point 530 or the communication device 540. This start possible signal is a signal notifying that irradiation of the radiation 511 can be started. In response to receiving the start possible signal, the radiation generation device 510 starts irradiating the radiation 511.

[0046] When the cumulative dose of the irradiated radiation 511 (cumulative irradiation dose) reaches a dose threshold, the radiation imaging apparatus 100 transmits an irradiation stop request signal to the radiation generation apparatus 510 via the access point 530 or the communication device 540 and the synchronization control apparatus 550. The irradiation stop request signal is a signal requesting the halt of irradiation of the radiation 511. In response to receiving the irradiation stop request signal, the radiation generation apparatus 510 stops irradiating the radiation 511. Here, the dose threshold is determined, for example, by the control unit 180 of the radiation imaging apparatus 100 based on the input dose value, the irradiation intensity of the radiation 511, communication delays between units, processing delays, etc. When the irradiation time of the radiation 511 reaches the input upper irradiation limit time, the radiation generation apparatus 510 may stop irradiating the radiation 511 even if it has not received the irradiation stop request signal.

[0047] After the irradiation of radiation 511 from the radiation generation device 510 is stopped, the radiation imaging device 100 sequentially scans the drive lines 110 (drive lines 110 other than the detection drive lines 111) to which only the imaging pixels 101 are connected. The radiation imaging device 100 then acquires a radiation image by reading out the electrical signals (image signals) of each imaging pixel 101 using the readout circuit 160. Since the charges (electrical signals) accumulated in the detection pixels 104 are read out during irradiation of radiation 511 and the correction pixels 107 are shielded from light, the electrical signals from these pixels cannot be used to form a radiation image. Therefore, the signal processing unit 170 of the radiation imaging device 100 interpolates pixel values ​​at the positions of the detection pixels 104 and the correction pixels 107 by performing an interpolation process using pixel values ​​of the imaging pixels 101 surrounding these pixels.

[0048] Fig. 6 is a timing chart showing an example of the operation of a radiation imaging system 500 including a radiation imaging apparatus 100 according to an embodiment of the present invention. The operation of the radiation imaging system 500 shown in Fig. 6 is performed by cooperation between a control unit 180 that controls the drive circuit 150 and readout circuit 160 and a signal processing unit 170 in the radiation imaging apparatus 100. The dose of radiation 511 irradiated to the radiation imaging apparatus 100 is determined by this operation.

[0049] 6, "radiation" indicates whether or not radiation 511 is being irradiated to the radiation imaging device 100. When "radiation" is low, radiation 511 is not being irradiated, and when "radiation" is high, radiation 511 is being irradiated.

[0050] In FIG. 6, "Vg1" to "Vgn" indicate drive signals supplied from the drive circuit 150 to the multiple drive lines 110. "Vgk" corresponds to the drive line 110 in the kth row (k=1, ..., total number of drive lines). As described above, some of the multiple drive lines 110 are also called detection drive lines 111. In FIG. 6, the jth detection drive line 111 is represented by "Vdj" (j=1, ..., total number of detection drive lines).

[0051] In FIG. 6, "φSH" indicates the level of the signal supplied to the sample-and-hold circuit SH of the amplifier 161. "φR" indicates the level of the signal supplied to the differential amplifier circuit AMP of the amplifier 161. "Detection pixel signal" indicates the value of the electrical signal read out from the detection pixel 104. "Correction pixel signal" indicates the value of the electrical signal read out from the correction pixel 107. "Cumulative exposure dose" indicates the cumulative dose value of the radiation 511 irradiated to the radiation imaging device 100.

[0052] In FIG. 6, at time t0, the control unit 180 starts a reset operation of a plurality of pixels in the pixel array region (imaging region) IR. Here, the reset operation refers to an operation of removing the charge (electrical signal) accumulated in the conversion element of each pixel, and more specifically, to supplying a drive signal to the drive line 110 to turn on the switch element of each pixel. The control unit 180 resets each pixel connected to the drive line 110 of the first row by controlling the drive circuit 150. Next, the control unit 180 resets each pixel connected to the drive line 110 of the second row. The control unit 180 repeats this operation up to the drive line 110 of the last row.

[0053] In FIG. 6, at time t1, the control unit 180 completes the reset operation of the drive lines 110 in the last row, and then repeats the reset operation again from the drive lines 110 in the first row.

[0054] In FIG. 6, at time t2, the control unit 180 receives a start request signal from the information processing device 520 via the communication unit 190. In response to receiving this start request signal, the control unit 180 performs the reset operation up to the last row and ends the reset operation. Note that the control unit 180 may end the reset operation before performing the reset operation up to the last row and proceed to the next process. For example, when the control unit 180 receives the start request signal during the reset operation of the drive line 110 of the kth row, the control unit 180 may proceed to the next process without performing the reset operation of the drive lines 110 of the (k+1)th row and onwards. In this case, the radiation imaging device 100 may reduce steps that may occur in the radiation image by adjusting the drive for acquiring the radiation image or by performing image processing on the radiation image.

[0055] In FIG. 6 , at time t3, the control unit 180 starts a determination operation for determining the dose of radiation 511 being irradiated to the radiation imaging device 100. In this determination operation, the control unit 180 repeatedly executes a readout operation to read out data from the detection pixels 104 and the correction pixels 107. Of the multiple readout operations from the detection pixels 104 and the correction pixels 107, one or more readout operations in the first half are performed to determine a correction value, and the repeated readout operations in the second half are performed to continuously determine the dose of radiation 511 at each point in time. This readout operation is executed on the detection drive line 111, and is not executed on the other drive lines 110. Specifically, the drive circuit 150 supplies a drive signal to one of the multiple drive lines 110 connected to at least one of the detection pixels 104 and the correction pixels 107 (i.e., the detection drive line 111). For this reason, the drive circuit 150 does not supply drive signals to any of the drive lines 110 that are not connected to either the detection pixel 104 or the correction pixel 107. Furthermore, the drive circuit 150 simultaneously supplies drive signals to any of the drive lines 110 that are connected to at least one of the detection pixel 104 and the correction pixel 107 (i.e., the detection drive line 111). As a result, electrical signals from multiple pixels connected to the same signal line 120 are combined and read out to the readout circuit 160. Because the detection pixel 104 and the correction pixel 107 are exclusively connected to the signal line 120, the readout circuit 160 can separately read out electrical signals from pixels with different sensitivities.

[0056] In FIG. 6, the control unit 180 performs an operation from time t3 to time t4 in one readout operation. Specifically, the control unit 180 temporarily supplies a drive signal to one or more detection drive lines 111. Thereafter, the control unit 180 temporarily sets the signal φSH to a high level, thereby holding in the sample-and-hold circuit SH the electrical signals read out from the pixels to the readout circuit 160 via the signal line 120. Thereafter, the control unit 180 temporarily sets the signal φR to a high level, thereby resetting the readout circuit 160 (specifically, the differential amplifier circuit AMP of the amplifier unit 161). When a region of interest (ROI) is set within the pixel array region (imaging region) IR, it is not necessary to read out electrical signals from detection pixels 104 that are not included in this region of interest (ROI).

[0057] Furthermore, the control unit 180 performs the readout operation one or more predetermined times to determine the above-described correction value. The signal processing unit 170 determines a correction value Od based on the signals read out from the detection pixels 104 by the predetermined number of readout operations, and a correction value Oc based on the signals read out from the correction pixels 107 by the predetermined number of readout operations. Here, the determination of the correction value Od will be described in detail. If the predetermined number is one, only one electrical signal is read out from the detection pixels 104, and the signal processing unit 170 sets the value of that electrical signal as the correction value Od. If the predetermined number is multiple, the signal processing unit 170 sets the average value of the multiple readout electrical signals as the correction value Od. Note that other statistical values ​​may be used instead of the average value. The correction value Oc is also determined based on the signals read out from the correction pixels 107. The signal processing unit 170 stores the correction values ​​Od and Oc determined in this manner in the memory unit 172 so that they can be used for subsequent processing.

[0058] In FIG. 6, after completing one or more readout operations, at time t5, the control unit 180 transmits a start possible signal to the radiation generation device 510 via the communication unit 190, the synchronization control device 550, etc. The determination of the correction values ​​Od and Oc described above may be performed before or after transmitting the start possible signal. After transmitting the start possible signal, the control unit 180 repeatedly executes the readout operation described above. Based on information from the signal processing unit 170, the control unit 180 measures the exposure dose DOSE of the radiation 511 for each readout operation and determines whether the accumulated value exceeds an accumulation threshold.

[0059] In FIG. 6, irradiation of radiation 511 begins at time t6, which is after time t5.

[0060] 6 , at time t8, when the cumulative irradiation dose reaches the cumulative threshold, the control unit 180 transmits an irradiation stop request signal to the synchronization control device 550 via the communication unit 190. Upon receiving this irradiation stop request signal, the synchronization control device 550 controls the radiation generation device 510 to stop irradiating the radiation 511. Note that instead of transmitting the irradiation stop request signal at time t8, the control unit 180 may estimate time t8 at which the cumulative irradiation dose will reach the cumulative threshold and transmit the irradiation stop request signal to the synchronization control device 550. For example, the control unit 180 may calculate an estimated transmission time t7 by taking into account the communication delay time required for a signal to reach the synchronization control device 550 from the communication unit 190 relative to the predicted arrival time of time t8 at which the cumulative irradiation dose will reach the cumulative threshold, and transmit the irradiation stop request signal at this estimated transmission time t7.

[0061] In FIG. 6, at time t9, the radiation generation device 510 stops emitting radiation 511 in response to the emission stop control from the synchronization control device 550.

[0062] In Figure 6, at time t10, the control unit 180 determines whether or not to read out the charge, which is an electrical signal accumulated in the imaging pixel 101, based on the status of the suspension of irradiation of radiation 511 by the radiation generating device 510 detected via the synchronization control device 550 and the accumulated irradiation dose.

[0063] 6, from time t11 to t12, the control unit 180 performs the same operation as from time t3 to time t4. The control unit 180 then controls the readout circuit 160 and the drive circuit 150 to accumulate charge in order to generate a correction image (Fixed Pattern Noise: FPN) for the imaging pixel 101. From the perspective of FPN correction accuracy, it is preferable that the control unit 180 aligns the time from time t11 to t12 with the time from time t3 to t10. Note that the control unit 180 can measure time by using the CPU system time, a timer, or a counter, for example.

[0064] Fig. 7 is a flowchart showing an example of the processing procedure of the control method for the radiation imaging apparatus 100 according to the embodiment of the present invention. In the processing of the flowchart shown in Fig. 7, the control unit 180 determines whether to stop irradiation of the radiation 511 based on information related to irradiation of the radiation 511, such as the start and end of irradiation of the radiation 511 from the radiation generation device 510, and information on the irradiation dose, communicated via the synchronization control device 550. Then, in the processing of the flowchart shown in Fig. 7, when the control unit 180 determines to stop irradiation, the readout circuit 160, which is a readout means, reads out electrical signals (charges) related to the radiographic image from the imaging pixels 101.

[0065] 7 starts, the radiation imaging apparatus 100 is powered on and transitions to a state in which the control unit 180 can communicate with the synchronization control device 550 and the information processing device 520 via the communication unit 190 etc. Then, the control unit 180 starts radiation imaging based on an irradiation request from the radiation generation device 510 via the synchronization control device 550.

[0066] 7, upon receiving an irradiation request from the radiation generation device 510, the control unit 180 resets the electrical signals (charges) of the detection pixels 104 and the correction pixels 107. The control unit 180 then controls the readout circuit 160 and the drive circuit 150 so that the detection pixels 104 can accumulate and read out electrical signals (charges) due to the radiation 511. That is, in step S701, the control unit 180 starts a process of detecting the dose of the radiation 511 using the detection pixels 104 (and the correction pixels 107).

[0067] 7, the control unit 180 resets the electrical signals (charges) of the imaging pixels 101 and controls the readout circuit 160 and drive circuit 150 so that the imaging pixels 101 accumulate the electrical signals (charges). That is, in step S702, the control unit 180 starts accumulating the electrical signals (charges) of the imaging pixels 101. The detection pixels 104, correction pixels 107, and imaging pixels 101 can control the drive circuits 150 in parallel, and it is preferable to process steps S701 and S702 simultaneously in terms of shortening the imaging time and reducing power consumption.

[0068] 7, the control unit 180 determines whether or not there is information related to the irradiation of radiation 511, such as the start or stop of irradiation of radiation 511, based on the communication status between the synchronization control device 550 and the radiation imaging device 100. For example, the information related to the irradiation of radiation 511 is information related to the reception of a start request signal or an irradiation stop signal, or information related to the transmission of a start possible signal or an irradiation stop request signal. Here, by determining whether there is communication including any one of these pieces of information, it is possible to determine whether or not there is information related to the irradiation of radiation 511 in the radiation imaging.

[0069] In step S703 of FIG. 7, if the control unit 180 determines that there is no information related to the irradiation of the radiation 511 (S703 / NO), it is assumed that the radiation generating device 510 has not yet irradiated the radiation 511, and therefore the process returns to step S701.

[0070] Also, in step S703 of FIG. 7, if the control unit 180 determines that there is information related to the irradiation of the radiation 511 (S703 / YES), the process proceeds to step S704. When the process proceeds to step S704 in FIG. 7, the control unit 180 determines whether or not the irradiation of the radiation 511 has stopped, based on the detection pixel signal (the irradiation dose of the radiation 511) read out from the detection pixel 104.

[0071] 7, if the control unit 180 determines that the irradiation of the radiation 511 has not stopped (S704 / NO), the process returns to step S701 because the irradiation of the radiation 511 by the radiation generation device 510 has not stopped due to a communication delay, a malfunction, etc. In this case of S704 / NO, the processes from step S705 onwards are not performed because there is a possibility that artifacts will occur in the radiographic image if the electrical signals of the imaging pixels 101 are read out during the irradiation of the radiation 511.

[0072] Also, in step S704 of FIG. 7, if the control unit 180 determines that the irradiation of the radiation 511 has stopped (S704 / YES), the process proceeds to step S705. 7, the control unit 180 controls the readout circuit 160 and the drive circuit 150 to reset the electrical signals (charges) of the detection pixels 104 and the correction pixels 107. That is, in step S705, the control unit 180 stops detecting the irradiation dose of the radiation 511 using the detection pixels 104.

[0073] 7, the control unit 180 controls the readout circuit 160 and the drive circuit 150 to read out the electrical signal (charge) of the imaging pixel 101. Before reading out the electrical signal (charge) of the imaging pixel 101, operations such as setting registers for the gain of the differential amplifier circuit AMP and for power saving mode are also included. The detection pixel 104, the correction pixel 107, and the imaging pixel 101 can control the drive circuit 150 in parallel, and it is preferable to process steps S705 and S706 simultaneously in terms of shortening the imaging time and reducing power consumption.

[0074] 7, the control unit 180 resets the electrical signals (charges) of the imaging pixels 101 and controls the readout circuit 160 and the drive circuit 150 to accumulate and read out the electrical signals (charges) of the imaging pixels 101. By performing the operation of this step in a state where radiation 511 is not being emitted from the radiation generation device 510, an image for FPN correction (corrected image) can be acquired. This corrected image can also be generated using the optimal accumulation time for each radiation imaging session (the same time as the time taken for steps S701 to S705).

[0075] When the process of step S707 in FIG. 7 is completed, the process of the flowchart shown in FIG. 7 is completed, but the process may return to step S701 in FIG. 7 and repeat the processes from step S701 onwards.

[0076] As described above, the control unit 180 can determine whether to stop irradiation of the radiation 511 (YES in S704 of FIG. 7) regardless of delays in communication with the synchronization control device 550 or the like or the state (failure or type) of the radiation generation device 510. As a result, when the readout circuit 160 determines to stop irradiation, it immediately reads out the electrical signals (charges) of the imaging pixels 101 (S706 of FIG. 7), thereby stabilizing the imaging time for radiation imaging and enabling efficient radiation imaging. In some cases, this can be expected to shorten the imaging time and reduce power consumption.

[0077] FIG. 8 shows an embodiment of the present invention and is a diagram for explaining a case where the control unit 180 in FIG. 1 determines whether to stop irradiation of the radiation 511 based on an electrical signal (detection pixel signal) acquired from the detection pixel 104.

[0078] FIG. 8(a) is a diagram illustrating an example of the relationship between radiation 511 and time. FIG. 8(b) is a diagram illustrating an example of the relationship between time and the electrical signal (detection pixel signal) of the detection pixel 104 for each frame (ROI). As shown in FIG. 8(a), the radiation 511 does not immediately become the desired output due to the performance of the radiation source in the radiation generating device 510, fluctuations in the radiation, and the like. However, the output generally stabilizes after a certain period of time. Therefore, as shown in FIG. 8(b), the detection pixel signal acquired from the detection pixel 104 also stabilizes over time. The irradiation of the radiation 511 is stopped by turning off the exposure switch of the radiation generating device 510 or by receiving an irradiation stop request signal from the radiation imaging device 100. The detection pixel signal shown in FIG. 8(b) decreases as the radiation 511 stops. The control unit 180 can determine whether the irradiation of the radiation 511 has stopped by determining whether the value of the detection pixel signal is less than a threshold value. This threshold value is determined in advance, for example, taking into account the dose value in the dark and afterimage characteristics. It is preferable to store thresholds according to irradiation conditions such as the length of accumulation time, mAs value, and region of interest (ROI) in the information processing device 520 or the like and set them in the radiation imaging device 100 before radiography. The detection pixel signals used in this determination method may be the results of multiple samplings and calculations. For example, noise can be smoothed by using a moving average. It is preferable that the detection pixels 104 to be sampled are those in the region of interest (ROI), which is a selected region selected from the pixel array region (imaging region) IR before radiography. In this case, the detection pixel signals of the detection pixels 104 outside the region of interest (ROI) may be dark or the aperture of the irradiation range may be inappropriate, which may reduce the accuracy of the above-mentioned determination.

[0079] FIG. 9 shows an embodiment of the present invention and is a diagram for explaining a case where the control unit 180 in FIG. 1 determines whether to stop irradiation of the radiation 511 based on the cumulative irradiation dose of the radiation 511 acquired from the detection pixel 104.

[0080] FIG. 9(a) is a diagram showing an example of the relationship between radiation 511 and time. FIG. 9(b) is a diagram showing an example of the relationship between the accumulated exposure dose of radiation 511 per frame (ROI) and time. As shown in FIG. 9(b), the detection pixel signal acquired by the detection pixel 104 increases as the radiation source stabilizes. The irradiation of radiation 511 is stopped when the exposure switch of the radiation generation device 510 is turned off or when an irradiation stop request signal is received from the radiation imaging device 100. The detection pixel signal decreases as the irradiation of radiation 511 stops, and the accumulated exposure dose stops increasing. The control unit 180 can determine whether the irradiation of radiation 511 has stopped by, for example, determining whether the accumulated exposure dose shown in FIG. 9(b) is equal to or greater than a threshold value. This threshold value is determined in advance, taking into account, for example, the dose value in the dark and the afterimage characteristics. It is preferable to store threshold values ​​according to irradiation conditions, such as the length of accumulation time and the mAs value, in the information processing device 520 or the like and set them in the radiation imaging device 100 before radiography.

[0081] FIG. 10 is a diagram for explaining a case where the radiation imaging device 100 according to an embodiment of the present invention controls detection of the start and end of irradiation of the radiation 511 and an irradiation stop request signal, and determines whether to stop irradiation of the radiation 511.

[0082] In FIG. 10, when the radiation generation apparatus 510 transmits an irradiation request to the synchronization control apparatus 550, the synchronization control apparatus 550 receives the irradiation request and transmits to the radiation imaging apparatus 100 information that an irradiation request has been made.

[0083] 10 , when the radiation imaging apparatus 100 receives an irradiation request at time t110, the control unit 180 resets the charge of the imaging pixel 101. Furthermore, the control unit 180 controls the readout circuit 160 and the drive circuit 150 so that the detection pixel 104 detects the dose of radiation 511 and the imaging pixel 101 accumulates charge. Furthermore, in order to improve the accuracy of the accumulated dose, the control unit 180 preferably subtracts the charge of the offset component from the electrical signal read out from the correction pixel 107 so that the charge is not accumulated in the detection pixel 104 as the accumulated dose. Then, the radiation imaging apparatus 100 prepares for imaging and notifies the synchronization control device 550 that imaging is possible.

[0084] In FIG. 10, at time t111, when the synchronization control device 550 determines that there is an irradiation request from the radiation generation device 510 and that imaging is possible with the radiation imaging device 100, it performs irradiation control so that the radiation generation device 510 irradiates radiation 511.

[0085] 10, at time t112, the radiation generation device 510 irradiates radiation 511 in response to an irradiation control signal from the synchronization control device 550. Then, the radiation imaging device 100 detects that the radiation 511 has been irradiated, and accumulates the dose of the radiation 511.

[0086] 10 , at time t113, when the cumulative dose value exceeds the irradiation start threshold, the control unit 180 of the radiation imaging apparatus 100 detects that irradiation of radiation 511 has started. For example, the irradiation start threshold can be determined based on a ratio of a dose target value set in advance by the information processing device 520.

[0087] 10 , at time t114, when the cumulative dose value exceeds the irradiation stop threshold, the control unit 180 of the radiation imaging apparatus 100 transmits an irradiation stop request to the synchronization control device 550, which is a request to stop the irradiation of the radiation 511. The irradiation stop threshold is a threshold for stopping the radiation 511 emitted from the radiation generation device 510 via the synchronization control device 550, and is determined, for example, taking into account a dose target value set in advance by the information processing device 520 and the amount of communication delay of each device. The control unit 180 determines whether the irradiation stop request has been transmitted to the synchronization control device 550, and if transmitted, starts determining whether the radiation 511 is being generated based on the detection pixel signals read from the detection pixels 104.

[0088] In FIG. 10, at time t115, the control unit 180 of the radiation imaging apparatus 100 detects the time when the cumulative dose value exceeds the dose target value.

[0089] In FIG. 10, at time t116, the synchronization control device 550 receives an irradiation stop request from the radiation imaging apparatus 100 and performs control to stop the irradiation of the radiation 511.

[0090] In FIG. 10, at time t117, when the radiation generation device 510 receives the irradiation stop control from the synchronization control device 550, the radiation generation device 510 stops irradiating the radiation 511.

[0091] 10, at time t118, the radiation imaging apparatus 100 receives from the radiation generation apparatus 510 via the synchronization control device 550 a notification that the irradiation of radiation 511 has stopped. At this time, the radiation imaging apparatus 100 receives the notification that the irradiation request has ended late due to a communication delay or the like. As a result, even though no radiation 511 is being generated, the charge of the imaging pixel 101 cannot be read out, resulting in unnecessary power consumption and imaging time (time t117 to time t118). For this reason, in this embodiment, it is preferable that the control unit 180 of the radiation imaging apparatus 100 reads the electrical signal (charge) of the imaging pixel 101 after determining to stop irradiation at time t117, regardless of the fact that the irradiation request has ended.

[0092] In particular, in the case of radiography in which the time for generating radiation 511 is short, unnecessary radiography time becomes large in the time taken up by one radiography, so it is possible to switch whether or not to make an irradiation stop determination depending on the irradiation time.

[0093] Furthermore, for example, the control unit 180 of the radiation imaging apparatus 100 may switch whether or not to make an irradiation stop determination based on the irradiation conditions and imaging conditions from the information processing device 520 before radiation imaging. For example, the control unit 180 may adopt a configuration in which, as the radiation irradiation condition, the control unit 180 does not make an irradiation stop determination when the radiation irradiation time is equal to or shorter than a predetermined time, and makes an irradiation stop determination in other cases. Furthermore, the control unit 180 may adopt a configuration in which, as the imaging condition, the control unit 180 does not make an irradiation stop determination in the case of the asynchronous imaging described above, and makes an irradiation stop determination in other cases of synchronous imaging.

[0094] Furthermore, for example, the control unit 180 of the radiation imaging apparatus 100 may switch whether or not to make a determination to stop irradiation based on a parameter such as the accumulation time.

[0095] As an example, the case has been described in which the determination of whether radiation 511 is being generated is started at time t114 based on the detection pixel values ​​read from the detection pixels 104. However, it is also possible to perform this determination at a timing that includes at least one of times t110 to t116 as information related to the irradiation of radiation 511. Furthermore, the synchronization control device 550 may transmit a response to the radiation imaging apparatus 100 at time t116 notifying that the irradiation stop request has been received. In this case, the radiation imaging apparatus 100 may perform the determination of whether to stop irradiation of radiation 511 after receiving the response to the irradiation stop request.

[0096] As another example, the control unit 180 may make the determination to stop irradiation of the radiation 511 even in a configuration in which the control unit 180 does not compare the cumulative dose value with the irradiation stop threshold and transmit a command to stop irradiation to the synchronization control device 550 .

[0097] The radiation imaging apparatus 100 can also be battery-powered, and the control unit 180 may switch whether or not to make an irradiation stop determination depending on the power supply and charge level of the battery. For example, the control unit 180 may be configured not to make an irradiation stop determination when the charge level of the battery, which is an example of information on power supply, is less than a predetermined level, and to make an irradiation stop determination in other cases.

[0098] Furthermore, the control unit 180 of the radiation imaging apparatus 100 may switch whether to make an irradiation stop determination depending on the form of communication with the synchronization control device 550 via the communication unit 190. For example, the control unit 180 may switch whether to make an irradiation stop determination depending on whether the communication is wireless or wired communication and the communication state (RSSI, transmission / reception rate, packet RTT (Round Trip Time), etc.) Specifically, for example, the control unit 180 may not make an irradiation stop determination when the form of communication with the synchronization control device 550 via the communication unit 190 is wired communication, and may make an irradiation stop determination when the communication is wireless communication or other wireless communication.

[0099] Furthermore, for example, the control unit 180 can determine whether to stop irradiation only if the RTT between the communication unit 190 and the synchronization control device 550 is longer than a certain time before radiation imaging begins, such as at time t110, thereby making it possible to perform the next imaging regardless of communication delays.

[0100] Fig. 11 is a diagram showing an example of a measurement field 1100 arranged in the radiation imaging device 100 according to an embodiment of the present invention. In Fig. 5, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0101] The measurement field 1100 shown in FIG. 11(a) is an area where the dose of radiation 511 is detected during radiography. As shown in FIG. 11(b), the dose of radiation 511 is detected by multiple detection pixels 104 arranged within the measurement field 1100. There are various methods for arranging multiple measurement fields 1100 in the radiation imaging device 100 (pixel array region (imaging region) IR). However, by arranging them symmetrically about the center of the radiation imaging device 100, the same arrangement can be achieved regardless of the orientation of the radiation imaging device 100. The shape of the measurement field 1100 may be a quadrilateral such as a square or rectangle, or a circle or ellipse. The shape of the measurement field 1100 may also be a shape that follows the shape of the subject H. In AEC, the dose of radiation 511 irradiated into the measurement field 1100 can be detected by reading out the outputs of the multiple detection pixels 104 arranged within the measurement field 1100 during radiation irradiation. The control unit 180 may perform the above-described irradiation stop determination based on the dose of radiation 511 detected by the detection pixels 104 of the measurement field 1100, which is a region selected in the pixel array region (imaging region) IR. Alternatively, the control unit 180 may perform the above-described irradiation stop determination based on the dose of radiation 511 detected by the detection pixels 104 of the measurement field 1100 other than the measurement field 1100 (other than the selected region) that was selected and set before radiography. For example, if the central measurement field 1100 is selected in radiography of a subject H such as a hand, using the other measurement fields 1100 allows the irradiation stop determination to be made based on the radiation 511 in the region where the subject H is not present, which is preferable in terms of accuracy as there is less blurring of the subject H and scattered radiation.

[0102] The radiation imaging apparatus 100 according to this embodiment is configured to be able to communicate with a synchronization control device 550 that controls a radiation generation device 510 that irradiates radiation 511. The radiation imaging apparatus 100 has a pixel array region (imaging region) IR that includes a plurality of pixels, including imaging pixels 101 that acquire electrical signals related to a radiation image and detection pixels 104 that detect the dose of the radiation 511 based on the electrical signals. The control unit 180 of the radiation imaging apparatus 100 according to this embodiment controls the transmission of a stop request signal to the synchronization control device 550 to stop the radiation generation device 510 from irradiating the radiation 511, based on the dose of the radiation 511 detected by the detection pixels 104. At the same time, the control unit 180 of the radiation imaging apparatus 100 according to this embodiment determines whether irradiation of the radiation 511 has been stopped. The readout circuit 160, which is a readout means of the radiation imaging apparatus 100 according to this embodiment, reads out electrical signals related to the radiation image from the imaging pixels 101 when the control unit 180 determines to stop irradiation. This configuration stabilizes the imaging time of radiation imaging, enabling efficient radiation imaging, and in some cases, can reduce imaging time and power consumption.

[0103] Furthermore, the control unit 180 of the radiation imaging apparatus 100 according to this embodiment performs an irradiation stop determination (YES in S704 of FIG. 7 ) based on the presence of information related to the irradiation of radiation 511 (YES in S703 of FIG. 7 ). Here, in this embodiment, for example, the control unit 180 may determine that information related to the irradiation of radiation 511 has been received when the control unit 180 transmits a stop request signal for irradiation of radiation 511 to the synchronization control device 550 or when the synchronization control device 550 receives the stop request signal. Alternatively, the control unit 180 may determine that information related to the irradiation of radiation 511 has been received when the control unit 180 transmits a start request signal for causing the radiation generation device 510 to start irradiating radiation 511 to the synchronization control device 550 or when the synchronization control device 550 receives the start request signal. Alternatively, the control unit 180 may determine that information related to the irradiation of radiation 511 has been received when the radiation generation device 510 receives the start request signal or when the radiation generation device 510 transmits a response to the start request signal to the synchronization control device 550. In addition, the control unit 180 may determine that there is information related to the irradiation of radiation 511 when it receives from the synchronization control device 550 that the irradiation of radiation has stopped, or when it detects that the irradiation of radiation has stopped based on the dose of radiation detected by the detection pixel 104.

[0104] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. This program and a computer-readable storage medium storing the program are included in the present invention.

[0105] It should be noted that the above-described embodiments of the present invention are merely illustrative examples of the implementation of the present invention, and the technical scope of the present invention should not be construed as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0106] The disclosure of this embodiment includes the following configuration, method, and program. [Configuration 1] A radiation imaging device configured to be able to communicate with a control device that controls a radiation generation device that irradiates radiation, a pixel array including a plurality of pixels that acquire electrical signals corresponding to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signals related to a radiographic image and detection pixels that detect the dose of the radiation based on the electrical signals; a control means for performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and for performing irradiation stop determination that the irradiation of the radiation has stopped; a readout means for reading out the electrical signals relating to the radiation image from the imaging pixels when the control means determines that the irradiation should be stopped; A radiation imaging apparatus comprising: [Configuration 2] The control means compares the radiation dose detected by the detection pixel with a preset threshold value to make the irradiation stop determination. 2. The radiation imaging device according to configuration 1, [Configuration 3] The control means calculates the radiation dose detected by the detection pixel from any one of an average value, an integrated value, and a differential value of the electrical signal acquired by the detection pixel. 3. The radiation imaging apparatus according to configuration 2. [Configuration 4] The control means determines whether to stop the irradiation based on the information related to the irradiation of the radiation. 4. The radiation imaging device according to any one of configurations 1 to 3. [Configuration 5] The control means determines that there is information related to the irradiation of radiation when the stop request signal is transmitted to the control device or when the control device receives the stop request signal. 5. The radiation imaging apparatus according to configuration 4. [Configuration 6] The control means determines that there is information related to the irradiation of radiation when it transmits a start request signal to the control device to start the irradiation of radiation in the radiation generating device, or when the control device receives the start request signal. 5. The radiation imaging apparatus according to configuration 4. [Configuration 7] When the radiation generating device receives a start request signal for starting irradiation of the radiation in the radiation generating device, or when the radiation generating device transmits a response to the start request signal to the control device, It is determined that there is information relating to the irradiation of radiation. 5. The radiation imaging apparatus according to configuration 4. [Configuration 8] The control means determines that there is information related to the radiation irradiation when it receives from the control device that the radiation irradiation has been stopped, or when it detects that the radiation irradiation has been stopped based on the dose of the radiation detected by the detection pixel. 5. The radiation imaging apparatus according to configuration 4. [Configuration 9] The control means switches whether or not to perform the irradiation stop determination based on the imaging conditions using the radiation or the irradiation conditions of the radiation. 9. The radiation imaging device according to any one of configurations 1 to 8. [Configuration 10] The control means switches whether or not to perform the irradiation stop determination based on information about power supply. 9. The radiation imaging device according to any one of configurations 1 to 8. [Configuration 11] The control means switches whether or not to perform the irradiation stop determination based on a communication mode with the control device. 9. The radiation imaging device according to any one of configurations 1 to 8. [Configuration 12] The control means determines whether to stop irradiation based on the amount of radiation detected by the detection pixels in the selected region of the pixel array. 9. The radiation imaging device according to any one of configurations 1 to 8. [Configuration 13] The control means determines whether to stop irradiation based on the amount of radiation detected by the detection pixels in an area other than the selected area in the pixel array. 9. The radiation imaging device according to any one of configurations 1 to 8. [Configuration 14] The readout means performs readout setting of the electrical signals acquired by the plurality of pixels before reading out the electrical signals related to the radiation image from the imaging pixels. 14. The radiation imaging device according to any one of configurations 1 to 13. [Method 1] The radiation generating device is configured to be able to communicate with a control device that controls the radiation generating device that irradiates radiation, a plurality of pixels that acquire an electrical signal corresponding to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signal related to a radiographic image and detection pixels that detect the dose of the radiation based on the electrical signal; A method for controlling a radiation imaging device including a pixel array comprising: a control step of performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and performing an irradiation stop determination that the irradiation of the radiation has stopped; a readout step of reading out the electrical signals relating to the radiation image from the imaging pixels when the irradiation stop determination is made in the control step; A method for controlling a radiation imaging apparatus, comprising: [Program 1] The radiation generating device is configured to be able to communicate with a control device that controls the radiation generating device that irradiates radiation, a plurality of pixels that acquire an electrical signal corresponding to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signal related to a radiographic image and detection pixels that detect the dose of the radiation based on the electrical signal; A program for causing a computer to execute a control method for a radiation imaging apparatus including a pixel array comprising: a control step of performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and performing an irradiation stop determination that the irradiation of the radiation has stopped; a readout step of reading out the electrical signals relating to the radiation image from the imaging pixels when the irradiation stop determination is made in the control step; A program that causes a computer to execute the following. [Explanation of symbols]

[0107] 100: Radiation imaging device, IR: pixel array region (imaging region), 101: imaging pixel, 104: detection pixel, 107: correction pixel, 110: drive line, 111: detection drive line, 120: signal line, 130: bias line, 140: power supply circuit, 150: drive circuit, 160: readout circuit, 170: signal processing unit, 180: control unit, 190: communication unit

Claims

1. A radiation imaging device configured to be able to communicate with a control device that controls a radiation generation device that irradiates radiation, a pixel array including a plurality of pixels that acquire electrical signals corresponding to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signals related to a radiographic image and detection pixels that detect the dose of the radiation based on the electrical signals; a control means for performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and for performing irradiation stop determination that the irradiation of the radiation has stopped; a readout means for reading out the electrical signals relating to the radiation image from the imaging pixels when the control means determines that the irradiation should be stopped; A radiation imaging apparatus comprising:

2. The control means compares the radiation dose detected by the detection pixel with a preset threshold value to make the irradiation stop determination.

2. The radiation imaging apparatus according to claim 1.

3. The control means calculates the radiation dose detected by the detection pixel from any one of an average value, an integrated value, and a differential value of the electrical signal acquired by the detection pixel.

3. The radiation imaging apparatus according to claim 2.

4. The control means determines whether to stop the irradiation based on the information related to the irradiation of the radiation.

2. The radiation imaging apparatus according to claim 1.

5. The control means determines that there is information related to the irradiation of radiation when the stop request signal is transmitted to the control device or when the control device receives the stop request signal.

5. The radiation imaging apparatus according to claim 4.

6. The control means determines that there is information related to the irradiation of radiation when it transmits a start request signal to the control device to start the irradiation of radiation in the radiation generating device, or when the control device receives the start request signal.

5. The radiation imaging apparatus according to claim 4.

7. The control means determines that there is information related to the radiation irradiation when the radiation generating device receives a start request signal for starting the radiation irradiation in the radiation generating device, or when the radiation generating device transmits a response to the start request signal to the control device.

5. The radiation imaging apparatus according to claim 4.

8. The control means determines that there is information related to the radiation irradiation when it receives from the control device that the radiation irradiation has been stopped, or when it detects that the radiation irradiation has been stopped based on the dose of the radiation detected by the detection pixel.

5. The radiation imaging apparatus according to claim 4.

9. The control means switches whether or not to perform the irradiation stop determination based on the imaging conditions using the radiation or the irradiation conditions of the radiation.

2. The radiation imaging apparatus according to claim 1.

10. The control means switches whether or not to perform the irradiation stop determination based on information about power supply.

2. The radiation imaging apparatus according to claim 1.

11. The control means switches whether or not to perform the irradiation stop determination based on a communication mode with the control device.

2. The radiation imaging apparatus according to claim 1.

12. The control means determines whether to stop irradiation based on the amount of radiation detected by the detection pixels in the selected region of the pixel array.

2. The radiation imaging apparatus according to claim 1.

13. The control means determines whether to stop irradiation based on the amount of radiation detected by the detection pixels in an area other than the selected area in the pixel array.

2. The radiation imaging apparatus according to claim 1.

14. The readout means performs readout setting of the electrical signals acquired by the plurality of pixels before reading out the electrical signals related to the radiation image from the imaging pixels.

2. The radiation imaging apparatus according to claim 1.

15. A control method for a radiation imaging device including a pixel array configured to be able to communicate with a control device that controls a radiation generation device that irradiates radiation, the pixel array including a plurality of pixels that acquire electrical signals corresponding to incident radiation, the pixels including imaging pixels that acquire the electrical signals related to a radiographic image and detection pixels that detect a dose of the radiation based on the electrical signals, a control step of performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and performing an irradiation stop determination that the irradiation of the radiation has stopped; a readout step of reading out the electrical signals relating to the radiation image from the imaging pixels when the irradiation stop determination is made in the control step; A method for controlling a radiation imaging apparatus, comprising:

16. A program for causing a computer to execute a control method for a radiation imaging device including a pixel array configured to be able to communicate with a control device that controls a radiation generation device that irradiates radiation, the pixel array including a plurality of pixels that acquire electrical signals corresponding to the incident radiation, the plurality of pixels including imaging pixels that acquire the electrical signals related to a radiographic image and detection pixels that detect a dose of the radiation based on the electrical signals, the program comprising: a control step of performing control to transmit a stop request signal to the control device to stop the irradiation of the radiation in the radiation generation device based on the dose of the radiation detected by the detection pixel, and performing an irradiation stop determination that the irradiation of the radiation has stopped; a readout step of reading out the electrical signals relating to the radiation image from the imaging pixels when the irradiation stop determination is made in the control step; A program that causes a computer to execute the following.

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