Radiation imaging apparatus, radiation imaging system, method for operating radiation imaging apparatus, and program

Abstract

To provide a radiation imaging apparatus that determines the end of fluorography to allow imaging processing without synchronous communication with a radiation generator.SOLUTION: A radiation imaging apparatus includes: a radiation detection part in which a plurality of pixels for radiation detection is disposed and which is used for generating image data on the basis of emitted radiation ray; and a determination part for determining that emission of a radiation ray is stopped when a reduction amount of exposure of a radiation ray which is obtained from a detection pixel included in the plurality of pixels is larger than a reduction threshold.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a radiation imaging apparatus, a radiation imaging system, an operation method of a radiation imaging apparatus, and a program. [Background technology]

[0002] Radiation imaging devices that perform synchronous communication with a radiation generating device to capture video are known. The connection of communication cables used for synchronous communication is cumbersome, and hinders the flexibility of system upgrades in video diagnostic vehicles and the like. In contrast, radiation imaging devices that capture still images without synchronous communication are also known. With these radiation imaging devices, users can capture images without being restricted by cable length in the capture location.

[0003] When synchronous communication is not performed, the radiation generating device and the radiation imaging device must perform processing at the same timing, and in order to perform continuous fluoroscopic imaging, it is necessary to determine the timing of the start and end of imaging. Patent Document 1 discloses a radiation imaging device that performs still image imaging without synchronous communication. This radiation imaging device performs standby driving to detect irradiation of radiation using a bias power supply of a power supply circuit, and starts imaging in response to detection of irradiation of radiation. Patent Document 2 discloses a radiation imaging device that determines the start and end of irradiation of radiation based on changes in the charge output signal of a radiation detection element, and performs accumulation (irradiation start) operation and readout (irradiation end) operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-192062 A [Patent Document 2] JP 2014-020971 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the radiation imaging device disclosed in Patent Document 1, it is necessary to perform standby driving for detecting irradiation of radiation before imaging. Therefore, it is not easy to handle processing in which imaging operations are performed continuously, such as continuous fluoroscopy. Similarly, in the radiation imaging device disclosed in Patent Document 2, it is not easy to handle processing in which imaging operations are performed continuously, such as continuous fluoroscopy.

[0006] Therefore, an object of the present disclosure is to enable an imaging process in a radiation imaging apparatus that determines the end of fluoroscopic imaging without performing synchronous communication with a radiation generation apparatus. [Means for solving the problem]

[0007] In order to achieve the above object, a radiation imaging apparatus according to an aspect of the present disclosure includes: a radiation detection unit in which a plurality of pixels for detecting radiation are arranged and used to generate image data based on the irradiated radiation; a determination unit that determines that the irradiation of radiation has been stopped when a decrease in the amount of irradiation of radiation obtained from a detection pixel included in the plurality of pixels is greater than a decrease threshold; Equipped with. Effect of the Invention

[0008] According to one aspect of the present disclosure, in a radiation imaging apparatus, imaging processing for determining the end of fluoroscopic imaging can be performed without performing synchronous communication with a radiation generation apparatus. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram illustrating an example of the configuration of a radiation imaging system according to a first embodiment of the present disclosure. [Diagram 2] 2 is a block diagram showing an example of the configuration of a radiation detection unit of the radiation imaging system of FIG. 1. [Diagram 3] 4 is a flowchart showing a series of imaging operations executed during fluoroscopic imaging by pulse irradiation in the first embodiment. [Figure 4]4 is a flowchart showing the imaging operation of fluoroscopic imaging in the flowchart shown in FIG. 3. [Diagram 5] 4 is a flowchart showing the imaging operation of fluoroscopic imaging by continuous irradiation of radiation in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, examples of a radiation imaging device, a radiation imaging system including the imaging device, and an operation method of the imaging device according to the present disclosure will be described with reference to the drawings. Note that the following examples do not limit the present disclosure according to the claims. Although the examples describe a number of features, not all of these features are essential to the present disclosure, and the features may be combined in any manner.

[0011] Furthermore, the dimensions, materials, shapes, and relative positions of components described in the following examples are arbitrary and can be changed according to the configuration of the device to which the present disclosure is applied or various conditions. In the drawings, the same or similar configurations are given the same reference numbers, and duplicated explanations are omitted. In the following explanation, X-rays are exemplified as radiation, but radiation to which the present disclosure is applicable also includes α-rays, β-rays, γ-rays, particle rays, cosmic rays, and the like.

[0012] Example 1 As a first embodiment of the present disclosure, a schematic configuration of a radiation imaging system including a radiation imaging apparatus according to the present disclosure and an operational process of the radiation imaging apparatus will be described below with reference to the accompanying Figs. 1 to 4.

[0013] <Configuration of the Radiation Imaging System of the Present Embodiment> 1 illustrates an example of the configuration of a radiation imaging system according to this embodiment. The radiation imaging system 1 includes a radiation imaging device 100 including a radiation detection unit 200, and a control device 400 which is a processing device that acquires image data from the radiation imaging device 100 and processes the acquired image data. It is more preferable that the radiation imaging system 1 further includes a radiation source 301 that irradiates radiation, and a radiation generating device 300 that controls the radiation source 301. The radiation imaging system 1 may also include an operation UI (User Interface) 302 that allows a user to operate the radiation generating device 300. The above-mentioned control device 400 and a display monitor 500 may be connected to the radiation imaging device 100.

[0014] The radiation imaging device 100 includes a radiation detection unit 200 that detects radiation and generates image data, and a control unit 101 that controls imaging and communication operations, and the control unit 101 controls the entire radiation imaging device. The control unit 101 includes a drive control unit 102, an image processing unit 104, a storage unit 106, a communication control unit 111, and an internal clock 113. The drive control unit 102 controls the drive of the radiation detection unit 200 and the acquisition of a radiation image, and includes an image acquisition control unit 103, an irradiation dose measurement unit 115, and a frame rate management unit 116. The image acquisition control unit 103 acquires the amount of charge accumulated due to irradiation of radiation, which is obtained when radiation is irradiated in a state in which charge can be accumulated in each pixel of the radiation detection unit 200 described later. This amount of charge is read out by the irradiation dose measurement unit 115 as image data to be used for generating a radiation image. The irradiation dose measurement unit 115 further includes a determination unit 117, which determines whether the radiation dose obtained from the detection pixels 204 and the detection drive lines 211 described below is larger than a predetermined increase and decrease in the radiation dose. Note that the determination by the determination unit is not limited to determining whether the radiation dose is larger than the increase and decrease in the radiation dose, but may be a determination of an increase or decrease in the rate of change in the radiation dose, a comparison of the radiation dose with a threshold, or any other known determination method. The frame rate management unit 116 manages the imaging cycle of fluoroscopic imaging.

[0015] The image processing unit 104 performs image processing on the image acquired from the radiation detection unit 200. The storage unit 106 includes an image data storage unit 107 for storing acquired image data, and a dose information storage unit 108 for storing dose information corresponding to imaging, and is configured from a volatile memory. The communication control unit 111 controls communication between the radiation generation device 300 and the control unit 101. The internal clock 113 is used to acquire the imaging time, elapsed time, etc. The image data, etc. stored in the storage unit 106 are transmitted to the control device 400, and further image processing and analysis of the image data are performed as necessary, and the results are displayed on the display monitor 500.

[0016] The imaging cycle (hereinafter referred to as the frame rate) managed by the frame rate management unit 116 is registered before fluoroscopic imaging is performed by the radiation imaging device 100. In this case, as a method of registration, the frame rate may be transmitted from the control unit 101 and registered, or an input screen for the frame rate may be provided on the display monitor 500 and the user may directly input the frame rate via the screen. Furthermore, the method of registering the frame rate is not limited to these methods and may be realized by other known methods.

[0017] Here, the control unit 101 can be configured by a computer provided with a processor and a memory. The control unit 101 may be configured by a general computer, or may be configured by a computer dedicated to a radiation imaging system. The control unit 101, together with the control device 400 and the display monitor 500, may be, for example, a personal computer, and a desktop PC, a notebook PC, a tablet PC (portable information terminal), or the like may be used. Furthermore, the control device 400 may be configured as a cloud-type computer in which some of the components are arranged in an external device.

[0018] Further, each component of the control unit 101 other than the memory unit 106 may be configured by a software module executed by a processor such as a central processing unit (CPU) or a micro processing unit (MPU) arranged in the control device 400. The processor may be a graphical processing unit (GPU) or a field-programmable gate array (FPGA). Each component may be configured by a circuit performing a specific function such as an ASIC. The memory unit 106 may be configured by any storage medium such as an optical disk such as a hard disk or a memory arranged in association with the control device 400.

[0019] The display monitor 500 can be configured with any display or the like, and displays various information such as subject information, various images, and a mouse cursor in accordance with a user's operation under the control of the control device 400. The display monitor 500 can also be an input device that issues instructions to the control unit 101, and specifically, a keyboard and a mouse can be attached to it. The display monitor 500 may be configured with a touch panel display. Also, the function of the operation UI 302 described later may be realized using the touch panel of the display monitor 500.

[0020] <Radiation Generator> The radiation generating device 300 includes an operation UI 302 for operating the radiation generating device 300. A user sets radiation irradiation conditions and the like via the operation UI 302. In response to this operation, the radiation generating device 300 continuously irradiates radiation in a pulsed manner. Note that in the present disclosure, no wired connection is made between the radiation generating device 300 and the radiation imaging device 100 for exchanging synchronization signals such as notifications of the start and end of radiation irradiation and notifications of timing when radiation irradiation is possible.

[0021] <Radiation detection section> Next, the radiation detection section 200 according to this embodiment will be described with reference to FIG. 2. FIG. 2 shows an example of the configuration of the radiation detection section 200. The radiation detection section 200 has an imaging region IR in which a plurality of radiation detection pixels are arranged, and a power supply circuit 240, a drive circuit 250, and a readout circuit 260 connected to the imaging region IR. In the imaging region IR, a plurality of pixels are arranged to form a plurality of rows and a plurality of columns, and generate electric charges by receiving irradiation of pulsed radiation irradiated by a radiation generating device 300. A plurality of drive lines 210 connecting the drive circuit 250 and the pixels are arranged so that each of them corresponds to one of the plurality of pixel rows. A plurality of signal lines 220 connecting the readout circuit 260 and the pixels are arranged so that each of them corresponds to one of the plurality of pixel columns. The read circuit 260 includes an amplifier 261 corresponding to the signal line 220, a multiplexer 262 connected to the amplifier 261, and an analog-to-digital converter (hereinafter, referred to as an AD converter) 263.

[0022] <Pixels for monitoring radiation dose> The multiple pixels arranged in the imaging region IR include multiple imaging pixels 201 used to acquire a radiation image, and one or more detection pixels 204 used to monitor the radiation exposure dose.

[0023] <Image acquisition using multiple pixels> The imaging pixel 201 includes a conversion element 202 that converts radiation into an electric signal, and a switch element 203 that connects the corresponding signal line 220 and the conversion element 202 to each other. The detection pixel 204 includes a conversion element 205 that converts radiation into an electric signal, and a switch element 206 that connects the corresponding signal line 220 and the conversion element 205 to each other. The detection pixel 204 is arranged so as to be included in a row and a column that are configured by a plurality of imaging pixels 201. In FIG. 2, the imaging pixel 201 and the detection pixel 204 are distinguished by applying different hatching to the conversion element 202 and the conversion element 205. In the illustrated example, the detection pixel 204 is arranged in the same row and column as the imaging pixel 201, but the arrangement of the detection pixel 204 is not limited to this example, and at least one detection pixel 204 may be arranged in the imaging region IR.

[0024] The conversion element 202 and the conversion element 205 may be composed of a scintillator that converts radiation into light and a photoelectric conversion element that converts light into an electrical signal. The scintillator is generally formed in a sheet shape so as to cover the imaging region IR, and is shared by a plurality of pixels. Alternatively, the conversion element 202 and the conversion element 205 may be composed of a conversion element that directly converts radiation into an electrical signal. The switch element 203 and the switch element 206 may include a thin film transistor (TFT) whose active region is composed of a semiconductor such as amorphous silicon or polycrystalline silicon. The detection pixel 204 also has a pixel configuration similar to that of the imaging pixel 201, and is connected to a corresponding drive line 210 and a corresponding signal line 220. The imaging pixel 201 may be connected to the same signal line 220 as the detection pixel 204.

[0025] <Radiation detection> A bias line 230 is connected to the power supply circuit 240, and the power supply circuit 240 includes a refresh power supply 241, a bias power supply 242, and an exposure detection means 243 in the circuit, and is configured to detect a change in bias current during radiation irradiation. More specifically, the power supply circuit 240 is driven by the drive control unit 102 so that the exposure detection means detects a change in bias current supplied to the conversion elements 202 and 205 via the bias line 230 during radiation irradiation. In this embodiment, the exposure detection means includes a current-voltage conversion circuit including an OP (Operational) amplifier and a resistor, and an AD converter that converts the converted voltage into a digital value. However, the aspect of the exposure detection means is not limited to this example, and other known current-voltage conversion circuits may be used, or the output voltage of the current-voltage conversion circuit may be used as it is. In addition, the current information output from the bias line 230 may be used as it is. The change in bias current detected by the power supply circuit 240 using the radiation exposure detection means, that is, the information on the start of radiation irradiation obtained in response thereto, is notified to the control unit 101 .

[0026] The power supply circuit 240 also supplies a voltage for refresh from a refresh power supply 241 to the conversion elements 202 and 205 via a bias line 230. The voltage for refresh is applied to the conversion elements 202 and 205 during the period of the refresh operation of these elements, and during the other periods, a bias voltage for obtaining the above-mentioned change in bias current is applied to these conversion elements.

[0027] <Detection line using pixels for radiation dose monitoring> Next, the operation of measuring the radiation dose using the radiation detection unit 200 will be described. The drive circuit 250 supplies drive signals to the pixels to be driven through the multiple drive lines 210 according to control signals from the drive control unit 102. By supplying the drive signals to the pixels to be driven, the signals stored in the conversion elements of the pixels become readable by the readout circuit 260. Note that, here, when the drive line 210 is connected to at least one of the detection pixels 204, the drive line 210 is referred to as a detection drive line 211. The drive control unit 102 monitors the change in the exposure dose by repeatedly reading out only each pixel in the pixel row connected to the detection drive line 211 including the detection pixel 204 while controlling the imaging pixel 201 to be in an accumulation state. Then, the exposure dose measurement unit 115 measures the increase or decrease in the exposure dose based on the dose information that is repeatedly read out.

[0028] <Radiation imaging> The readout circuit 260 is configured to read out signals from a plurality of pixels through a plurality of signal lines 220. As described above, the readout circuit 260 includes a plurality of amplifiers 261, a multiplexer 262, and an AD converter 263. Each of the plurality of signal lines 220 is connected to a corresponding one of the plurality of amplifiers 261 of the readout circuit 260. One signal line 220 corresponds to one amplifier 261. The multiplexer 262 selects the plurality of amplifiers 261 in a predetermined order, and supplies a signal from the selected amplifier 261 to the AD converter 263. The AD converter 263 converts the supplied signal into a digital signal. The image data converted into a digital value is stored in the storage unit 106 in FIG. 1.

[0029] The image acquisition control unit 103 acquires a radiographic image based on image data acquired by irradiating radiation, and an offset image or other image based on image data acquired without irradiating radiation. More specifically, the image acquisition control unit 103 reads out image data acquired by irradiating radiation during accumulation of each pixel, and stores this as a radiographic image in the storage unit 106. By continuously performing this operation, it becomes possible to capture a radiographic image as a moving image.

[0030] By executing the above-described process, charges corresponding to radiation are accumulated from the irradiation of radiation by the radiation generating device 300 to the radiation imaging device 100, and one still image is obtained by reading out the accumulated charges. On the other hand, when performing moving image capture, if radiation is irradiated at a timing when the radiation imaging device 100 cannot acquire an image, this will result in ineffective exposure, which is harmful to the subject. Therefore, moving image capture is possible by periodically and alternately repeating the irradiation of radiation for acquiring a radiation image and the readout of charges. In moving image capture, one radiation irradiation and one readout of charges constitute one frame process, and the frame process is periodically maintained during radiation irradiation, and a series of starts and stops of the alternating operations must be performed.

[0031] <Shooting process> Next, an imaging operation using the radiation generating apparatus 300 and the radiation imaging apparatus 100 in this embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing a series of operations executed by the control unit 101 during fluoroscopic imaging by irradiation of radiation in this embodiment. Although not shown in the figure, a subject such as a person is placed between the radiation source 301 and the radiation detection unit 200 during the imaging process described below. The radiation irradiated from the radiation source 301 passes through this subject, and the radiation detection unit 200 detects the radiation that has passed through the subject or the radiation that has not passed through the subject.

[0032] <Imaging device starts up ~ standby for shooting> For example, when the radiation imaging apparatus 100 is powered on, the control unit 101 executes an imaging preparation operation, and the imaging operation described below is started. When the imaging operation is started, first, in step S301, the control unit 101 starts radiation detection using the power supply circuit 240, more specifically, the radiation exposure detection means 243. Specifically, as described above, the radiation exposure detection means 243 starts detection of a change in current in the bias line 230. The power supply circuit 240 sequentially performs a refresh operation and a process of detecting a change in current in the bias line 230 for each pixel row. The process of detecting a change in current due to radiation irradiation in step S302 is periodically repeated until the radiation generation device 300 irradiates the radiation imaging apparatus 100 with radiation. Note that the imaging cycle managed by the frame rate management unit 116 is changed during the period from power-on to detection of radiation irradiation. When the current value changes and the radiation irradiation is detected by the radiation exposure detection means 243, the flow proceeds to step S303, and the detection of radiation by the control unit 101 using the power supply circuit 240 is stopped.

[0033] <Radiation exposure~photography> After the radiation detection is stopped, the flow proceeds to step S304, and the irradiation dose measurement unit 115, more specifically the determination unit 117, starts monitoring the increase or decrease of the irradiation dose using the detection pixel 204 and the detection drive line 211. After the start of the irradiation dose monitoring, the flow proceeds to step S305, and the image acquisition control unit 103 starts fluoroscopic imaging of the subject in step S305. In this embodiment, fluoroscopic imaging is performed in which the radiation generator 300 irradiates pulses of radiation, but the radiation irradiation may be continuous irradiation. In this embodiment, the irradiation dose is monitored using the detection drive line 211, but the dose may be monitored by individually operating the detection pixel 204. Alternatively, the dose may be monitored by disposing another means for measuring the irradiation dose without using the detection drive line 211 or the detection pixel 204.

[0034] <Shooting in progress> Next, the fluoroscopic imaging process performed in step S305 will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the imaging operation of fluoroscopic imaging. When fluoroscopic imaging is started, the flow proceeds to step S401. In step S401, first, the image acquisition control unit 103 starts the accumulation operation of charges by each pixel of the radiation detection unit 200. When the accumulation operation is started, the flow proceeds to step S402.

[0035] After the accumulation starts, in step S402, the determination unit 117 monitors the increase in the irradiation dose at the detection pixel 204 using the detection drive line 211. When the determination unit 117 detects an increase in the irradiation dose equal to or greater than the increase threshold, it is determined that radiation is being irradiated, and the image acquisition control unit 103 shifts the flow to step S403. When the determination unit 117 detects that the increase in the irradiation dose is smaller than the increase threshold, it is determined that radiation is not being irradiated, and the image acquisition control unit 103 shifts the flow to step S406.

[0036] In step S406, the image acquisition control unit 103 judges whether or not a time corresponding to one frame rate has elapsed since the start of accumulation based on information on the frame rate (imaging cycle) managed by the frame rate management unit 116. If it is judged that the time corresponding to one frame rate has not elapsed, the flow returns to step S402, and the judgment unit 117 monitors the increase in the radiation dose again. Note that this increase threshold value may be a fixed value or a variable value. If it is judged that the time corresponding to one frame rate has elapsed, it is determined that the subject is not irradiated with radiation, and the fluoroscopic imaging is terminated. Note that if it is judged that the time corresponding to one frame rate has elapsed in step S406 after the flow passes through step S405 described later, the last image captured is stored in the image data storage unit 107 as imaging data, and the fluoroscopic imaging is terminated.

[0037] In step S403, the determination unit 117 monitors the amount of reduction in the irradiation dose at the detection pixel 204 using the detection drive line 211. When the determination unit 117 detects a reduction in the irradiation dose equal to or greater than the reduction threshold, it is determined that the irradiation of radiation has been stopped, and the image acquisition control unit 103 transitions the flow to step S404.

[0038] In step S403, when the determination unit 117 detects that the amount of decrease in the exposure dose is smaller than the decrease threshold, it is determined that radiation is being irradiated, and the image acquisition control unit 103 moves the flow to step S407. In step S407, based on the information on the frame rate (shooting cycle) managed by the frame rate management unit 116, the image acquisition control unit 103 determines whether or not a time corresponding to one frame rate has elapsed since the start of accumulation. If it is determined that the time corresponding to one frame rate has not elapsed, it is determined that the accumulation operation is being performed, and the flow returns to step S403, and the amount of decrease in the radiation dose is monitored again. If it is determined that the time corresponding to one frame rate has not elapsed, the image acquisition control unit 103 moves the flow to step S408.

[0039] If it is determined in step S407 that the time corresponding to one frame rate has elapsed, it can be determined that no reduction in the irradiation dose was detected when pulsed radiation was being irradiated from the radiation generating device 300. In this case, the drive control unit 102 stores the last captured image in the image data storage unit 107, and in step S408, notifies the user that the end of irradiation could not be detected, for example, using the display monitor 500, and ends the fluoroscopic imaging. Note that the method of notifying the user that detection could not be detected is not limited to the embodiment using the display monitor 500, and any known notification method such as a buzzer or a voice message can be used.

[0040] In step S404, the image acquisition control unit 103 ends the accumulation operation in the radiation detection unit 200. By detecting the end of radiation irradiation in step S403 and ending the accumulation operation accordingly, the radiation generation device 300 and the radiation imaging device 100 are synchronized with each other with respect to the end of radiation irradiation. Note that the threshold value of the amount of decrease in the radiation dose in step S403 may be a fixed value or a variable value. When the accumulation operation ends, the image acquisition control unit 103 shifts the flow to step S405, reads out the accumulated charges, and performs image acquisition. When the image acquisition control unit 103 ends image acquisition for one frame in step S405, the flow returns to step S401, and the processing of each subsequent step is repeated.

[0041] <After the shoot> After the fluoroscopic imaging is completed, the drive control unit 102 shifts the flow from step S305 to step S306 in Fig. 3 and stops the irradiation dose monitoring by the detection drive line 211. In the subsequent step S306, the drive control unit 102 judges whether or not an instruction to continue imaging after stopping the irradiation dose monitoring by the detection drive line 211 has been received from the control device 400 (step S307). If it is judged that an instruction to perform imaging has been received, the flow returns to step S301, the operation of detecting radiation irradiation using the power supply circuit 240 is started again, and the next imaging is awaited. If it is judged that an instruction to perform imaging has not been received, the imaging ends as it is.

[0042] In this embodiment, a decision to continue imaging is made after the monitoring of the increase or decrease in the irradiation dose by the detection drive line 211 is stopped, but the radiation detection operation using the power supply circuit 240 may be started without making any particular decision. Also, the radiation imaging apparatus 100, instead of the control apparatus 400, may have an input device for imaging instructions, and may start the radiation detection operation using the power supply circuit 240 based on instructions from the input device.

[0043] In general, in radiography, the radiation irradiation device and the radiation imaging device perform synchronous communication to operate in sync. Even if synchronous communication is not performed, it is necessary to operate in sync, but the timing will gradually shift due to a difference in the management accuracy of the timing of both devices, and pace adjustment will be necessary. For example, if the irradiation section and the readout start process overlap, it is possible to determine whether a synchronization error has occurred by re-reading the readout process based on whether charge has accumulated in the corresponding part. In this method, it is constantly checked whether the operations are performed in sync, and the start and end of imaging are determined by transmitting a signal notifying the timing. In such a case, the power consumption for synchronization becomes large, which increases battery consumption, and imaging becomes impossible without synchronization.

[0044] By using the configuration according to the present disclosure, it is possible to detect the start of irradiation by detecting a change in a bias current that operates with a lower power than the power used when performing irradiation dose detection. Therefore, it is possible to detect irradiation while suppressing power consumption during standby for imaging, which leads to an improvement in the battery life of the radiation imaging device. Furthermore, by making it possible to determine the end of imaging, it is possible to know which image was last acquired, and it is possible to perform a last image hold that displays the last image at the end of fluoroscopic imaging. In addition, since the end of imaging can be reliably grasped, it is possible to immediately move to shooting standby driving for the next imaging after the last imaging. In addition, by determining the end of video imaging based on irradiation dose detection and frame rate, it is possible to stop the imaging drive in a short time after imaging, and it is possible to obtain effects such as a reduction in power consumption and an improvement in image quality by making it easier to secure time for preparation for the next imaging, for example, updating correction data. For example, when still image imaging is performed following fluoroscopic imaging, when there is a large change in the imaging operation situation, time is required for preparation driving in the operating environment of the new imaging (still image imaging in this example). Therefore, since it is necessary to quickly end the current imaging (fluoroscopic imaging in this example), the imaging end determination by this technology is useful. The end of video capture refers to the end of continuous irradiation of pulsed radiation (the end of irradiation of pulsed radiation at a certain frame rate).

[0045] (Modification of the first embodiment) In the first embodiment, a case is described in which radiation is irradiated in pulses, and one frame of image data is obtained corresponding to one pulse of irradiation. In contrast, in this modified example, a case is described in which fluoroscopic imaging is performed by continuously irradiating radiation. Note that, regarding the configuration described in the first embodiment and each step in the flowchart during imaging, the same or similar parts as those in the first embodiment are denoted by the same reference numerals, etc., and detailed explanations thereof will be omitted here.

[0046] This modification is different from the first embodiment in the process corresponding to step S403 in the fluoroscopic imaging of the first embodiment. Here, this different process will be described. The processes in other steps performed during the fluoroscopic imaging are the same as those in the first embodiment shown in FIG. 4. In this modification, as shown in FIG. 5, instead of step S403, a process of comparing the decrease in the radiation dose with a threshold value shown in step S503 is performed. Specifically, the irradiation dose measurement unit 115 monitors the decrease in the irradiation dose in the detection pixel 204 using the detection drive line 211. When the determination unit 117 detects an amount of decrease in the irradiation dose equal to or greater than the threshold value, it is determined that the irradiation of radiation has been stopped, and the image acquisition control unit 103 shifts the flow to step S404. The subsequent processes and threshold values ​​are the same as those described in the first embodiment.

[0047] When the determination unit 117 detects that the decrease in the exposure dose is smaller than the threshold, it is determined that the radiation exposure is continuing, and the process of step S503 is repeated again. The process of step S503 is repeated until the exposure dose measurement unit 115 detects a decrease in the exposure dose equal to or greater than the threshold. By executing such a process, it becomes possible to obtain image data by continuous radiation exposure.

[0048] Example 2 In the above-described first embodiment, after the radiation imaging apparatus 100 is started, the start of fluoroscopic imaging is determined by radiation detection using the power supply circuit 240. However, the application example of the present disclosure is not limited thereto. In the configuration of the radiation imaging apparatus 100 etc. described in the first embodiment, the detection pixel 204 and the detection drive line 211 may be used to monitor the irradiation dose from the first time and detect an increase in the irradiation dose to start fluoroscopic imaging.

[0049] However, constant monitoring of the radiation dose consumes a lot of power, so it is preferable in terms of power consumption to initially determine when to start fluoroscopy based on radiation detection, which consumes less power.

[0050] As described above, the radiation imaging device 100 according to an embodiment of the present disclosure includes the radiation detection unit 200, the detection unit (243), and the determination unit 117. The radiation detection unit 200 includes a plurality of radiation detection pixels 201, 204 arranged therein, and is used to generate image data based on the irradiated radiation. The detection unit exemplified by the exposure detection means 243 detects that irradiation of radiation from the radiation source 301 has started based on a change in bias current supplied to the plurality of pixels 201, 204. The determination unit 117 determines that irradiation of radiation has stopped when the amount of decrease in the amount of irradiation of radiation obtained from the detection pixel 204 included in the plurality of pixels 201, 204 is greater than a decrease threshold. In this manner, the detection unit detects that irradiation of radiation has started, and the determination unit 117 detects that irradiation of radiation has stopped, thereby making it possible to specify the timing of the start and stop of irradiation. With this configuration, it is possible to specify the timing of the stop of pulse irradiation of radiation, in particular, and thus to capture a radiation image corresponding to pulse irradiation of radiation without performing synchronous communication.

[0051] The radiation imaging device 100 may further include a frame rate management unit 116 that manages a frame rate related to the acquisition timing of image data. The determination unit 117 determines that radiation is not being irradiated when the increase in the amount of radiation irradiation obtained from the detection pixel 204 is smaller than an increase threshold. In this case, if the determination that irradiation is not being performed within one frame time managed by the frame rate management unit 116 is not changed, an instruction to end the acquisition of image data can be generated for the image acquisition control unit 103. If the determination that irradiation is not being performed within the frame rate is changed, the determination unit 117 can determine whether or not the decrease in the amount of radiation irradiation obtained from the detection pixel 204 is greater than a decrease threshold. In this manner, in the present disclosure, after the detection unit detects irradiation of radiation, the detection pixel 204 is used to first confirm the irradiation state of radiation, specifically, whether irradiation is being performed, based on the frame rate. The power supply circuit 240 supplies a bias voltage and a refresh voltage to the multiple pixels 201 and 204 using the same bias line 230. When detecting irradiation, the power supply circuit 240 performs a refresh operation and a bias line current monitoring operation sequentially for each pixel column. Therefore, if the bias current monitoring operation is performed after the start of image data acquisition, there is a possibility that the image data for each column may be destroyed. As described above, after the detection unit detects the start of irradiation, the detection pixel 204 is used to check the continuation of irradiation, etc., and the exposure detection means 243 is stopped, thereby eliminating the possibility of such data destruction.

[0052] Furthermore, when the determination unit 117 determines that irradiation is not performed within the frame rate, the determination unit 117 determines whether or not the increase in the amount of radiation irradiation obtained from the detection pixel 204 is smaller than the increase threshold within the frame rate after the determination. In this case, when it is determined that the increase is equal to or greater than the increase threshold, the generation of image data by the radiation detection unit 200 is continued. Then, when the decrease in the amount of radiation irradiation obtained from the detection pixel 204 is smaller than the decrease threshold, the determination unit 117 determines that radiation irradiation is being performed. Then, when the determination that irradiation is being performed within the frame rate managed by the frame rate management unit 116 is not changed, an instruction to end the acquisition of image data can be generated for the image acquisition control unit 103. Furthermore, when an instruction to end the acquisition of image data is generated, the radiation imaging device 100 can further include a means, such as a display monitor 500, for notifying the user that it has not been detected that irradiation of radiation has stopped.

[0053] The radiation imaging device 100 according to the embodiment of the present disclosure described above further includes a control unit (drive control unit 102) that controls the operation of the detection unit. When the detection unit detects that irradiation of radiation has started, the control unit stops the operation of the detection unit. Then, the determination unit 117 determines the irradiation state of radiation while the operation of the detection unit is stopped. As described above, it is not appropriate to monitor the bias current after the acquisition of image data has started. In this way, by stopping the detection operation of the detection unit by the control unit, it is possible to eliminate the possibility of such data destruction. In addition, there are cases where the amount of decrease in the amount of irradiation of radiation is greater than the decrease threshold, and the determination that irradiation is not being performed within the managed frame rate is not changed after the determination unit 117 determines that irradiation of radiation has stopped. In such a case, the control unit operates the detection unit to wait for the next irradiation of radiation. This allows the next frame to be continuously captured during pulse irradiation.

[0054] In the radiation imaging device 100 according to the embodiment of the present disclosure described above, the detection pixel 204 is disposed in the radiation detection section 200 as a pixel other than the pixel (other than 201) used to generate image data among the multiple pixels 201, 204 disposed two-dimensionally. The detection pixel 204 may be provided at a specific position among the two-dimensionally disposed pixels, or may be disposed randomly. The number of the detection pixel 204 is also not particularly limited. Although image data cannot be obtained from the portion where the detection pixel 204 is disposed, image data corresponding to this pixel can be generated by a known interpolation technique or the like and used.

[0055] Moreover, one aspect of the present disclosure can also configure a radiation imaging device 100 that enables moving image capture by receiving radiation that is continuously irradiated in a pulsed form (hereinafter, pulse radiation). The radiation imaging device 100 capable of capturing moving images includes a conversion element (220, 225), an acquisition unit (image acquisition control unit 103), a readout unit (readout circuit 260), and a determination unit 117. The conversion element is capable of generating charges in response to irradiation with pulsed radiation. The readout unit reads out the charges generated by the conversion element. The image acquisition control unit 103, which is exemplified as one aspect of the acquisition unit, can acquire information on the frame rate of moving image capture that is managed by the frame rate management unit 116. The determination unit 117 can determine the end of moving image capture based on the change in the charges read out by the readout unit and the information on the frame rate acquired by the acquisition unit.

[0056] In such a configuration, the information on the frame rate can include the time required to acquire one frame (one frame time). In such a case, when one frame time has elapsed without the increase in the charge read by the readout unit exceeding the threshold, the determination unit 117 can determine that the moving image capture has ended. Furthermore, the determination unit 117 can determine the end of the irradiation of the pulsed radiation. In such a case, the readout unit can determine the end of the irradiation of the pulsed radiation based on a change in the readout charge. More specifically, the determination unit 117 can determine the end of the irradiation of the pulsed radiation when the decrease in the charge read by the readout unit exceeds a threshold. Furthermore, the determination unit 117 can also determine the start of the moving image capture. In such a case, the determination unit 117 can determine the start of the moving image capture based on a change in the bias current supplied to the multiple pixels.

[0057] The present disclosure can also configure a radiation imaging system 1. In this case, the radiation imaging system 1 includes the above-described radiation imaging device 100 and a radiation generating device 300 capable of emitting radiation independently of the radiation imaging device 100. The present disclosure can also configure an operating method for causing the radiation imaging device 100 to perform the processes executed by the detection unit (243) and the determination unit 117 for the above-described radiation detection unit 200.

[0058] As described above, according to the radiation imaging device of the present disclosure, before the start of imaging, the start of radiation irradiation is detected by driving the power supply circuit 240. After the radiation irradiation is detected and it is determined that imaging has started, the exposure dose is monitored by the detection pixel 204 and the detection drive line 211, and the end of imaging is determined. By determining the start and end of imaging in this manner, radiation imaging can be performed without synchronous communication. Furthermore, by monitoring the exposure dose by the detection pixel 204 and the detection drive line 211 only during imaging, power consumption during standby for imaging can be reduced. Furthermore, by determining the end of imaging by monitoring the exposure dose by the detection pixel 204 and the detection drive line 211, it is possible to quickly move to standby driving for the next imaging. Furthermore, by being able to determine the end of imaging, it is possible to determine the final image, and it is possible to perform a last image hold that displays the last image at the end of fluoroscopic imaging.

[0059] The above disclosure includes the following configurations. (Configuration 1) a radiation detection unit in which a plurality of pixels for detecting radiation are arranged and used to generate image data based on the irradiated radiation; a determination unit that determines that the irradiation of radiation has been stopped when a decrease in the amount of irradiation of radiation obtained from a detection pixel included in the plurality of pixels is greater than a decrease threshold; A radiation imaging apparatus comprising: (Configuration 2) A frame rate management unit that manages a frame rate related to the acquisition timing of the image data, The radiation imaging device of configuration 1, wherein the determination unit determines that radiation is not being irradiated when an increase in the amount of radiation irradiation obtained from the detection pixel is smaller than an increase threshold, and generates an instruction to terminate acquisition of the image data when the determination that the irradiation is not being performed is not changed within a frame rate managed by the frame rate management unit. (Configuration 3) A radiation imaging device as described in configuration 2, wherein when the judgment that the irradiation is not performed within the frame rate is changed, the judgment unit judges whether the decrease in the irradiation amount of radiation obtained from the detection pixel is greater than a decrease threshold value. (Configuration 4) A radiation imaging device as described in configuration 2 or 3, wherein if it is determined that the irradiation is not occurring within the frame rate, the determination unit determines whether or not an increase in the amount of irradiation of radiation obtained from the detection pixel is smaller than the increase threshold within the frame rate after the determination, and if it is determined that the increase is equal to or greater than the increase threshold, the generation of the image data by the radiation detection unit continues. (Configuration 5) A frame rate management unit that manages a frame rate related to the acquisition timing of the image data, A radiation imaging device described in any one of configurations 1 to 4, wherein the determination unit determines that the radiation is being irradiated when the amount of decrease in the radiation irradiation amount obtained from the detection pixel is smaller than a decrease threshold, and generates an instruction to terminate acquisition of the image data when the determination that the irradiation is being performed within the frame rate managed by the frame rate management unit is not changed. (Configuration 6) 6. The radiation imaging apparatus according to claim 5, further comprising: a means for notifying a user that it has not been possible to detect that the irradiation of radiation has stopped when an instruction to end the acquisition of the image data is generated. (Configuration 7) 7. The radiation imaging apparatus according to any one of configurations 1 to 6, further comprising a detection unit configured to detect start of irradiation of radiation based on a change in bias current supplied to the plurality of pixels. (Configuration 8) a frame rate management unit that manages a frame rate related to the acquisition timing of the image data; A control unit that controls the operation of the detection unit, The control unit stops the operation of the detection unit when the detection unit detects that the irradiation of the radiation has started, 8. The radiation imaging apparatus according to configuration 7, wherein the determination unit performs the determination in a state in which the operation of the detection unit is stopped. (Configuration 9) a frame rate management unit that manages a frame rate related to the acquisition timing of the image data; A control unit that controls the operation of the detection unit, The radiation imaging device of configuration 7 or 8, wherein, after the determination unit determines that the decrease in the radiation irradiation dose is greater than a decrease threshold and that the irradiation of the radiation has been stopped, if the determination that the irradiation is not being performed within the frame rate managed by the frame rate management unit is not changed, the control unit operates the detection unit to wait for the next radiation irradiation. (Configuration 10) The radiation imaging device according to any one of configurations 1 to 9, wherein the detection pixels are arranged in the radiation detection section as pixels other than pixels used to generate image data among a plurality of pixels arranged two-dimensionally. (Configuration 11) A radiation imaging device capable of capturing moving images by receiving continuous irradiation of pulsed radiation, A conversion element capable of generating electric charges in response to irradiation with pulsed radiation; An acquisition unit that acquires information regarding a frame rate of video shooting; a readout unit that reads out the charges generated by the conversion element; a determination unit that determines the end of video capture based on the change in the charge read by the readout unit and information related to the frame rate obtained by the acquisition unit; and, A radiation imaging apparatus comprising: (Configuration 12) The radiation imaging device of configuration 11, wherein the information regarding the frame rate acquired by the acquisition unit is one frame time, and the determination unit determines that video recording has ended when the one frame time has elapsed without the increase in the amount of charge read by the readout unit exceeding a threshold value. (Configuration 13) 13. The radiation imaging device according to configuration 11 or 12, wherein the determination unit is capable of determining whether to stop the irradiation of the pulsed radiation, and determines whether to stop the irradiation of the pulsed radiation based on a change in the electric charge read by the readout unit. (Configuration 14) 14. The radiation imaging apparatus according to configuration 13, wherein the determination section determines that the irradiation of the pulsed radiation has stopped when a decrease in the electric charge read by the read section exceeds a threshold value. (Configuration 15) 15. The radiation imaging apparatus according to any one of configurations 11 to 14, wherein the determination unit is capable of determining a start of moving image capture and determines the start of moving image capture based on a change in bias current supplied to the plurality of pixels. (Configuration 16) A radiation imaging device according to any one of configurations 1 to 15, a processing device that acquires image data from the radiation imaging device and processes the acquired image data; A radiation imaging system comprising: (Method 1) 1. A method for operating a radiation imaging apparatus including a radiation detection unit in which a plurality of pixels for detecting radiation are arranged and used to generate image data based on irradiated radiation, comprising the steps of: determining that the irradiation of the radiation has been stopped when a decrease in the amount of irradiation of the radiation obtained from a detection pixel included in the plurality of pixels is greater than a decrease threshold value; A method of operating a radiation imaging device, comprising: (Method 2) The method for operating a radiation imaging device according to Method 1, further comprising detecting that irradiation of radiation has started based on a change in bias current supplied to the plurality of pixels. (program) A program which, when executed by a computer, causes the computer to carry out each step of the operating method according to method 1 or 2.

[0060] (Other Examples) The present invention also includes a program that realizes one or more functions of the above-described embodiments, and can also be realized by providing the program 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. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. A computer has one or more processors or circuits, and can include separate computers or a network of separate processors or circuits to read and execute computer-executable instructions.

[0061] The processor or circuitry may include a central processing unit (CPU), a microprocessing unit (MPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), or a field programmable gateway (FPGA), and the processor or circuitry may include a digital signal processor (DSP), a data flow processor (DFP), or a neural processing unit (NPU).

[0062] Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above embodiments and modifications. The present invention also includes inventions that have been modified within the scope of the present invention and inventions equivalent to the present invention. In addition, the above embodiments and modifications can be appropriately combined within the scope of the present invention. [Explanation of symbols]

[0063] 100: Radiation imaging device 101: Control unit 102: Drive control unit 200: Radiation detection unit 300: Radiation Generator 301:Radiation source

Claims

1. a radiation detection unit in which a plurality of pixels for detecting radiation are arranged and used to generate image data based on the irradiated radiation; a determination unit that determines that the irradiation of radiation has been stopped when a decrease in the amount of irradiation of radiation obtained from a detection pixel included in the plurality of pixels is greater than a decrease threshold; A radiation imaging apparatus comprising:

2. A frame rate management unit that manages a frame rate related to the acquisition timing of the image data, 2. The radiation imaging device of claim 1, wherein the determination unit determines that radiation is not being irradiated when an increase in the amount of radiation irradiation obtained from the detection pixel is smaller than an increase threshold, and generates an instruction to terminate acquisition of the image data when the determination that the irradiation is not being performed is not changed within a frame rate managed by the frame rate management unit.

3. The radiation imaging device according to claim 2 , wherein when the determination that the irradiation is not being performed within the frame rate is changed, the determination unit determines whether or not a decrease in the irradiation amount of the radiation obtained from the detection pixel is greater than a decrease threshold value.

4. 3. The radiation imaging device of claim 2, wherein, when it is determined that the irradiation is not being performed within the frame rate, the determination unit determines whether or not an increase in the amount of irradiation of radiation obtained from the detection pixel is smaller than the increase threshold within the frame rate after the determination, and when it is determined that the increase is equal to or greater than the increase threshold, the generation of the image data by the radiation detection unit is continued.

5. A frame rate management unit that manages a frame rate related to the acquisition timing of the image data, 2. The radiation imaging device of claim 1, wherein the determination unit determines that the radiation is being irradiated when the amount of decrease in the radiation irradiation dose obtained from the detection pixel is smaller than a decrease threshold, and generates an instruction to terminate acquisition of the image data when the determination that the irradiation is being performed within a frame rate managed by the frame rate management unit is not changed.

6. The radiation imaging apparatus according to claim 5 , further comprising: a unit for notifying a user that it has not been possible to detect that the irradiation of radiation has stopped when an instruction to end the acquisition of the image data is generated.

7. The radiation imaging apparatus according to claim 1 , further comprising a detection unit configured to detect the start of irradiation of radiation based on a change in bias current supplied to the plurality of pixels.

8. a frame rate management unit that manages a frame rate related to the acquisition timing of the image data; A control unit that controls the operation of the detection unit, The control unit stops the operation of the detection unit when the detection unit detects that the irradiation of the radiation has started, The radiation imaging apparatus according to claim 7 , wherein the determination section performs the determination in a state in which the operation of the detection section is stopped.

9. a frame rate management unit that manages a frame rate related to the acquisition timing of the image data; A control unit that controls the operation of the detection unit, 8. The radiation imaging device of claim 7, wherein, after the determination unit determines that the amount of decrease in the radiation irradiation dose is greater than a decrease threshold and that the irradiation of the radiation has been stopped, if the determination that the irradiation is not being performed within a frame rate managed by the frame rate management unit is not changed, the control unit operates the detection unit to wait for the next radiation irradiation.

10. The radiation imaging apparatus according to claim 1 , wherein the detection pixels are arranged on the radiation detection section as pixels other than pixels used to generate image data among a plurality of pixels arranged two-dimensionally.

11. The radiation imaging apparatus according to claim 1 , a processing device that acquires image data from the radiation imaging device and processes the acquired image data; A radiation imaging system comprising:

12. 1. A method for operating a radiation imaging apparatus including a radiation detection unit in which a plurality of pixels for detecting radiation are arranged and used to generate image data based on irradiated radiation, comprising the steps of: determining that the irradiation of the radiation has been stopped when a decrease in the amount of irradiation of the radiation obtained from a detection pixel included in the plurality of pixels is greater than a decrease threshold value; A method of operating a radiation imaging device, comprising:

13. The method of claim 12, further comprising detecting that irradiation of radiation has started based on a change in bias current supplied to the plurality of pixels.

14. A program which, when executed by a computer, causes the computer to carry out each step of the operating method according to claim 12 or 13.

15. A radiation imaging device capable of capturing moving images by receiving continuous irradiation of pulsed radiation, A conversion element capable of generating electric charges in response to irradiation with pulsed radiation; An acquisition unit that acquires information regarding a frame rate of video shooting; a readout unit that reads out the charges generated by the conversion element; a determination unit that determines an end of video capture based on the change in the charge read by the readout unit and information regarding the frame rate obtained by the acquisition unit; A radiation imaging apparatus comprising:

16. 16. The radiation imaging device according to claim 15, wherein the information about the frame rate acquired by the acquisition unit is one frame time, and the determination unit determines that video capture has ended when the one frame time has elapsed without the increase in the amount of charge read by the readout unit exceeding a threshold value.

17. The radiation imaging apparatus according to claim 15 , wherein the determination section is capable of determining whether or not to stop the irradiation of the pulsed radiation, and determines whether or not to stop the irradiation of the pulsed radiation based on a change in the electric charge read out by the readout section.

18. The radiation imaging apparatus according to claim 17 , wherein the determination section determines that the irradiation of the pulsed radiation has stopped when a decrease in the electric charge read by the readout section exceeds a threshold value.

19. The radiation imaging apparatus according to claim 15 , wherein the determination section is capable of determining a start of moving image capture, and determines the start of moving image capture based on a change in bias current supplied to the plurality of pixels.

20. The radiation imaging apparatus according to claim 15 , a processing device that acquires image data from the radiation imaging device and processes the acquired image data; A radiation imaging system comprising:

Images