Patent Publication Number: US-2022237775-A1

Title: Radiographic imaging system, radiographic imaging apparatus, and inspection method for inspecting radiographic imaging apparatus

Description:
BACKGROUND 
     Field of the Disclosure 
     The present disclosure relates to a radiographic imaging system, a radiographic imaging apparatus, and an inspection method for inspecting a radiographic imaging apparatus. 
     Description of the Related Art 
     Currently, as an imaging apparatus used in medical diagnostic imaging or nondestructive inspection with radiation, a radiographic imaging apparatus using a flat-panel detector (hereinafter “FPD”) formed of a semiconductor material is prevalent. For example, in medical diagnostic imaging, such a radiographic imaging apparatus is used as a digital imaging apparatus capable of performing still image capturing such as general image capturing and moving image capturing such as fluoroscopic image capturing in a radiographic imaging system. 
     The radiographic imaging system has the function of monitoring the irradiation dose of radiation, and in a case where the irradiation dose reaches a target value, ending the emission of the radiation (e.g., outputting a signal for stopping the emission of the radiation to a radiation source). This function is termed automatic exposure control (hereinafter “AEC”), and for example, can prevent the excessive emission of radiation. 
     Japanese Patent Application Laid-Open No. 2019-146039 discusses a radiographic imaging apparatus including, in a dose detection region in a pixel array in which pixels for outputting image signals according to radiation (image output pixels) are disposed in a two-dimensional matrix, pixels for detecting the irradiation dose of the radiation (dose detection pixels). 
     Japanese Patent Application Laid-Open No. 2019-146039 discusses a technique for monitoring the irradiation dose of the radiation by adding signals of dose detection pixels placed in a plurality of rows in the dose detection region in the pixel array. To improve the accuracy of correction of a defective pixel present in the dose detection region using pixels near the defective pixel, Japanese Patent Application Laid-Open No. 2019-146039 also discusses a technique for disposing at least one row of image output pixels between the defective pixel and a row in which dose detection pixels are disposed. 
     In the technique of Japanese Patent Application Laid-Open No. 2019-146039, in a case where a plurality of defective pixels occurs when an FPD is manufactured, a minimum of one row of image output pixels may not be able to be placed between two rows in which dose detection pixels are placed. If such an FPD is used, a defective pixel is not corrected with high accuracy, and the grade of an image decreases. Thus, the FPD cannot normally perform radiographic imaging involving an AEC function. 
     Thus, when an FPD is manufactured, then based on the state of a defective pixel in the dose detection region, it is determined whether the FPD can normally perform radiographic imaging involving the AEC function. If a criterion for normality is set too strictly when the determination is made, normality is determined as abnormality, whereby the yield in the manufacturing of the FPD decreases. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, a method for appropriately determining whether the FPD can normally perform radiographic imaging involving the AEC function is provided, and the above issue is solved by a radiographic imaging system including a radiographic imaging apparatus having a pixel array, the pixel array including a dose detection region where dose detection pixels for outputting signals to be used to detect a dose of emitted radiation is provided, the radiographic imaging system including a determination unit configured to, based on position information regarding positions in the dose detection region of at least either normal pixels or defective pixels among the dose detection pixels, determine whether radiographic imaging involving the detection of the dose of the radiation can be normally performed. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating a configuration of a radiographic imaging system according to a first exemplary embodiment. 
         FIG. 2  is a diagram illustrating a configuration of a radiographic imaging apparatus according to the first exemplary embodiment. 
         FIG. 3  is a flow illustrating processing from extraction of defective pixels to determination according to the first exemplary embodiment. 
         FIG. 4  is a flow for determining the radiographic imaging apparatus according to the first exemplary embodiment. 
         FIGS. 5A and 5B  are diagrams illustrating a method for determining whether center coordinates of normal pixels included in dose detection pixels satisfy a criterion according to the first exemplary embodiment. 
         FIGS. 6A and 6B  are diagrams illustrating a method for determining whether the number of defective pixels included in the dose detection pixels satisfies a criterion with respect to each sub-region according to the first exemplary embodiment. 
         FIG. 7  is a flow illustrating processing from a start to an end of imaging of an object according to the first exemplary embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     With reference to the attached drawings, suitable exemplary embodiments to which the present invention is applied will be described in detail below. 
     In a radiographic imaging system according to the present invention, typically, radiation can be an X-ray. The radiographic imaging system according to the present invention, however, can also be applied to a radiographic imaging system using not only an X-ray but also another type of radiation (e.g., an α-ray, a β-ray, or a γ-ray). 
     First, a first exemplary embodiment of the present invention is described.  FIG. 1  is a diagram illustrating the overall configuration of a radiographic imaging system  200  according to the first exemplary embodiment of the present invention. The radiographic imaging system  200  according to the present invention is particularly used in medical applications. The radiographic imaging system  200  includes a radiation emission unit  201 , a radiographic imaging apparatus  202 , and a console  203 . 
     The radiation emission unit  201  emits radiation to an object P. The radiation emission unit  201  includes a radiation generation unit (an X-ray tube) as a radiation generation device, a collimator that defines the beam spread angle of radiation generated by the radiation generation unit, and a radiation dose measuring device attached to the collimator. 
     The radiographic imaging apparatus  202  is a flat-panel detector (FPD) and includes two-dimensionally distributed image sensors. The details of the configuration of the radiographic imaging apparatus  202  will be described below with reference to  FIG. 2 . The radiographic imaging apparatus  202  detects the two-dimensional distribution of radiation having reached the radiographic imaging apparatus  202  and generates radiographic image data. The radiographic imaging apparatus  202  transmits the generated radiographic image data to an image processing unit  223 . The radiographic imaging apparatus  202  also transmits information regarding the dose of the detected radiation to an image capturing control unit  221  and a determination unit  222 . The details of the image capturing control unit  221 , the determination unit  222 , and the image processing unit  223  will be described below. 
     The console  203  includes a control device  210 , an input device  211 , and an image display device  212 . As the form of the console  203 , a general-purpose computer may be used, or the console  203  may be provided as an operation panel dedicated to the radiographic imaging system  200 . 
     The control device  210  is a device for controlling the radiographic imaging system  200 . As the control device  210 , a central processing unit (CPU) in a computer is used. The control device  210  includes the image capturing control unit  221 , the determination unit  222 , and the image processing unit  223 . As the input device  211 , a keyboard, a mouse, and a touch panel are used, and an operator inputs imaging conditions such as an image capturing part, a target dose of radiation to be emitted to the object P, and a tube voltage. The input imaging conditions are transmitted to the image capturing control unit  221 . 
     The image display device  212  displays a captured radiographic image and a screen for inputting imaging conditions. As the image display device  212 , a general-purpose display is used. Alternatively, the image display device  212  may function also as the input device  211  using a touch panel. 
     Based on information regarding imaging conditions transmitted from the input device  211  and information regarding the dose of radiation received from the radiographic imaging apparatus  202 , the image capturing control unit  221  controls the radiation emission unit  201  and the radiographic imaging apparatus  202 . 
     Based on information regarding the dose of radiation transmitted from the radiographic imaging apparatus  202 , the determination unit  222  determines whether each pixel in the radiographic imaging apparatus  202  is a normal pixel or a defective pixel. Further, based on the result of determining whether each pixel in the radiographic imaging apparatus  202  is a normal pixel or a defective pixel, the determination unit  222  determines whether the radiographic imaging apparatus  202  can normally detect the irradiation dose. The details of the determination will be described below. The determination unit  222  is provided in the console  203  in the present exemplary embodiment, but may be provided in the radiographic imaging apparatus  202 . In this case, the function of the determination unit  222  may be achieved using a CPU provided in the radiographic imaging apparatus  202 . 
     The image processing unit  223  performs processes such as a gradation process and a noise reduction process on radiographic image data transmitted from the radiographic imaging apparatus  202 . The image processing unit  223  transmits the processed radiographic image data to the image display device  212 . The image display device  212  outputs image information transmitted from the image processing unit  223 . 
     With reference to  FIG. 2 , the configuration of the radiographic imaging apparatus  202  is described. The radiographic imaging apparatus  202  includes a pixel array in which image output pixels  20211  and dose detection pixels  20212  are arranged in a two-dimensional array. An effective pixel region  2021  in the radiographic imaging apparatus  202  includes the image output pixels  20211 . The image output pixels  20211  are pixels that detect radiation having reached the radiographic imaging apparatus  202  and generate charges according to the radiation to generate radiographic image data. 
     The effective pixel region  2021  also includes a dose detection region  2022  that detects the irradiation dose of radiation. The dose detection region  2022  includes the image output pixels  20211  and the dose detection pixels  20212  that are pixels for detecting the irradiation dose of emitted radiation. The dose detection pixels  20212  in the dose detection region  2022  are formed in three rows. 
     With reference to  FIG. 3 , the flow of an inspection for determining the radiographic imaging apparatus  202  according to the first exemplary embodiment of the present invention is illustrated below. In the first exemplary embodiment, the processing of this inspection flow is performed in the step of manufacturing the radiographic imaging apparatus  202 . 
     In step S 101 , the operator inputs a tube voltage kV, a tube current mA, and an irradiation time ms as imaging conditions using the input device  211 . The input imaging conditions are transmitted to the image capturing control unit  221 . 
     In step S 102 , based on the information regarding the received imaging conditions, the image capturing control unit  221  controls the radiation emission unit  201  to emit radiation under the conditions of the tube voltage kV, the tube current mA, and the irradiation time ms. 
     Then, the image capturing control unit  221  transmits an image capturing control signal to the radiographic imaging apparatus  202 . Then, based on the received image capturing control signal, the radiographic imaging apparatus  202  controls the image output pixels  20211  and the dose detection pixels  20212  to convert radiation having reached the radiographic imaging apparatus  202  into dose information signals with respect to each pixel. 
     In step S 103 , the radiographic imaging apparatus  202  transmits the dose information signals with respect to each pixel of the dose detection pixels  20212  to the determination unit  222 . 
     In step S 104 , the determination unit  222  determines whether the dose information signals with respect to each pixel of the dose detection pixels  20212  received in step S 103  are greater than or equal to a normal pixel determination threshold Smin determined in advance and is less than or equal to a normal pixel determination threshold Smax determined in advance. The determination unit  222  determines as a defective pixel a pixel that is not a pixel that is greater than or equal to the normal pixel determination threshold Smin and is less than or equal to the normal pixel determination threshold Smax. 
     In step S 105 , the determination unit  222  saves coordinate information regarding the pixels determined as the defective pixels in step S 104  within the determination unit  222 . 
     In step S 106 , the determination unit  222  determines whether the defective pixels extracted in step S 104  are in an acceptable range where the radiographic imaging apparatus  202  detects the irradiation dose. The details of the determination will be described below. 
     In step S 107 , the determination unit  222  transmits information regarding the determination result to the image display device  212 . The image display device  212  displays the information regarding the determination result to the operator. Based on the displayed result, the operator determines whether to capture the object P. By the above processing, the flow from the extraction of defective pixels to the quality determination is completed. 
     With reference to  FIG. 4 , the flow of the determination made by the determination unit  222  in step S 106  is described below. 
     In step S 401 , if the total number of the defective pixels counted in step S 104  is less than or equal to a criterion N 1  as a criterion value (Yes in step S 401 ), the determination unit  222  determines that the defective pixels are acceptable. Then, the processing proceeds to step S 404 . If, on the other hand, the total number of the defective pixels exceeds the criterion N 1  (No in step S 401 ), the processing proceeds to step S 402 . In step S 402 , the image capturing control unit  221  determines whether the deviation of the center coordinates of normal pixels included in the dose detection pixels  20212  in the dose detection region  2022  is less than or equal to a criterion G. This determination method will be described below. If it is determined in step S 402  that the deviation is less than or equal to the criterion G (Yes in step S 402 ), the processing proceeds to step S 403  in  FIG. 4 . 
     In step S 403 , with respect to each of regions obtained by dividing the dose detection region  2022 , the determination unit  222  counts the number of defective pixels included in the dose detection pixels  20212  and determines whether the number of defective pixels included in the dose detection pixels  20212  is less than or equal to a criterion N 2  as a criterion value. Then, the determination unit  222  determines whether the defective pixels are acceptable. If the defective pixels are acceptable (Yes in step S 403 ), the processing proceeds to step S 404 . If the defective pixels are unacceptable (No in step S 403 ), the processing proceeds to step S 405 . In steps S 404  and S 405 , it is determined that the defective pixels are either acceptable or unacceptable. Then, the flow in  FIG. 4  ends. 
     With reference to  FIGS. 5A and 5B , a specific method for the determination made by the determination unit  222  in step S 402  is described below. 
     First, as illustrated in  FIG. 5A , the determination unit  222  sets X-coordinates and Y-coordinates in the dose detection region  2022 . The center of the X-coordinates and the Y-coordinates is matched to the center of the dose detection region  2022 . Then, the image capturing control unit  221  extracts coordinates (Xn, Yn) of normal dose detection pixels  20212  included in the dose detection region  2022 . Then, using formulas illustrated in  FIG. 5B , the determination unit  222  calculates center coordinates (Wx, Wy) of the normal dose detection pixels  20212  included in the dose detection region  2022 . 
     Then, the determination unit  222  determines whether the calculated center coordinates Wx and Wy are both less than or equal to the criterion G as a criterion value for the deviation of the center. If it is determined that the center coordinates Wx and Wy are greater than the criterion G, the determination unit  222  determines that the defective pixels are unacceptable. The reason for the determination that the defective pixels are unacceptable is that the center of the dose detection region  2022  and the center of dose detection pixels  20212  used to detect the dose are shifted from each other, whereby the dose cannot be normally detected. If the dose cannot be normally detected, the dose value of radiation to be actually emitted to the radiographic imaging apparatus  202  is highly likely to exceed a clinically acceptable value. 
     If it is determined that the center coordinates Wx and Wy are less than or equal to the criterion G, the processing proceeds to step S 403  in the flow in  FIG. 4 . 
     With reference to  FIGS. 6A and 6B , a specific method for the determination made in step S 403  is described below. 
     As illustrated in  FIGS. 6A and 6B , the determination unit  222  further divides the dose detection region  2022  into sub-regions, namely regions a, b, c, and d. With respect to each of the regions a, b, c, and d, the determination unit  222  determines whether the number of defective pixels included in the dose detection pixels  20212  is less than or equal to the criterion N 2 . 
     If the number of defective pixels included in the dose detection pixels  20212  is less than or equal to the criterion N 2  in all of the regions a, b, c, and d, the processing proceeds to step S 404  in the flow in  FIG. 4 . In step S 404 , the determination unit  222  that determines that the defective pixels are acceptable. If the number of defective pixels included in the dose detection pixels  20212  exceeds the criterion N 2  in any one of the regions a, b, c, and d, the processing proceeds to step S 405  in the flow in  FIG. 4 . In step S 405 , the determination unit  222  determines that the defective pixels are unacceptable. 
     The reason for the determination that the defective pixels are unacceptable is that if defective pixels concentrate in a particular region, irradiation dose information regarding the particular region cannot be detected, and the dose cannot be normally detected. If the dose cannot be normally detected, the dose value of radiation to be emitted to the radiographic imaging apparatus  202  is highly likely to exceed a clinically acceptable value. 
     In the example illustrated in  FIG. 6A , the number of defective pixels included in the dose detection pixels  20212  exceeds the criterion N 2  in the regions a and d. Thus, the determination unit  222  determines that the defective pixels are unacceptable. In the example illustrated in  FIG. 6B , the number of defective pixels included in the dose detection pixels  20212  is less than or equal to the criterion N 2  in all of the regions a, b, c, and d. Thus, the determination unit  222  determines that the defective pixels are acceptable. By the above processing, it can be determined whether the defective pixels extracted in step S 104  are in the acceptable range where the radiographic imaging apparatus  202  detects the irradiation dose. 
     That is, in the present invention, the determination unit  222  as a determination unit determines whether the dose of radiation can be normally detected. The determination is made based on position information regarding the positions in the dose detection region  2022  of at least either normal pixels or defective pixels among the dose detection pixels  20212 . 
     The position information regarding the positions in the dose detection region  2022  is, as illustrated in  FIG. 5A , information regarding the positions of the normal pixels or the defective pixels relative to the dose detection region  2022  in the radiographic imaging apparatus  202  as a target of the determination. In the present exemplary embodiment, the position information regarding the positions in the dose detection region  2022  is information representing the positions where the normal pixels or the defective pixels are present in the dose detection region  2022 , as XY-coordinates. The position information also includes values calculated based on the XY-coordinates. 
     A method for the determination based on the position information is performed by, for example, obtaining the deviation between the geometric center of the dose detection region  2022  and the geometric center of the normal pixels and comparing the deviation with a criterion value determined in advance. Alternatively, the method for the determination is also performed by comparing the number of defective pixels included in each of the sub-regions obtained by further dividing the dose detection region  2022  with a criterion value determined in advance. Yet alternatively, the method for the determination may be a method other than the above determination methods so long as the method is based on information regarding the positions of the normal pixels or the defective pixels relative to the dose detection region  2022 . 
     With reference to  FIG. 7 , the flow from the start to the end of the imaging of an object according to the first exemplary embodiment of the present invention is illustrated below. 
     In step S 201 , the operator inputs the targets of the tube voltage kV, the tube current mA, and a target dose Yp using the input device  211 . The input imaging conditions are transmitted to the image capturing control unit  221 . 
     In step S 202 , based on the information regarding the received imaging conditions, the image capturing control unit  221  controls the radiation emission unit  201  to emit radiation to the object P under the conditions of the tube voltage kV and the tube current mA. Then, the image capturing control unit  221  transmits an object image capturing control signal to the radiographic imaging apparatus  202 . Then, based on the received image capturing control signal, the radiographic imaging apparatus  202  controls the image output pixels  20211  and the dose detection pixels  20212  to convert radiation having reached the radiographic imaging apparatus  202  into dose information signals Y′p, m, and n with respect to each pixel. At this time, the dose detection pixels  20212  are driven in a shorter accumulation time than the image output pixels  20211  and at a higher frame rate than the image output pixels  20211 . 
     In step S 203 , the radiographic imaging apparatus  202  transmits the dose information signals Y′p, m, and n with respect to each pixel of the dose detection pixels  20212  to the image capturing control unit  221 . Y′p is the value of the dose, and m and n are the X-coordinate and the Y-coordinate, respectively, illustrated in  FIG. 5A . 
     In step S 204 , the image capturing control unit  221  performs a defect correction process on the dose information signals Y′p, m, and n with respect to each pixel of the dose detection pixels  20212  received in step S 203 . Signals output from defective pixels cannot be used for image data, and therefore are excluded. Thus, the image capturing control unit  221  excludes signals of pixels corresponding to the coordinates of the defective pixels among the dose detection pixels  20212  saved in step S 104  from the dose information signals Y′p, m, and n with respect to each pixel of the dose detection pixels  20212  received in step S 203 . Generally, a portion where each defective pixel is excluded is corrected using information regarding pixels around the defective pixel. 
     For example, the average value of signals of eight pixels around the defective pixel may be the output value of the portion where the defective pixel has been present. Alternatively, for example, a value calculated by appropriately weighting the signals of the eight pixels around the defective pixel may be the output value of the portion where the defective pixel has been present. The correction of the defective pixel is not limited to the correction using the eight pixels around the defective pixel, and the number of pixels and a region to be used may be variable. 
     In step S 205 , the image capturing control unit  221  calculates an average value Y′p (average) of all pixel signals of the dose information signals Y′p, m, and n with respect to each pixel of the dose detection pixels  20212 , except the signals excluded in step S 204 . 
     In step S 206 , the image capturing control unit  221  adds Y′p (average) calculated in step S 205  to Y′p (integration) that is information regarding the dose of radiation having reached the radiographic imaging apparatus  202  after having passed through the object P. The initial value of Y′p (integration) is 0. 
     In step S 207 , the image capturing control unit  221  determines whether Y′p (integration) calculated in step S 206  is less than Y′p (target) that is the target dose received in step S 201 . If it is determined that Y′p (integration) is less than the target dose (Yes in step S 207 ), the processes of steps S 203  to S 206  are repeated. If it is determined that Y′p (integration) is greater than or equal to Y′p (target) (No in step S 207 ), the processing proceeds to step S 208 . 
     In step S 208 , the image capturing control unit  221  transmits a radiation emission end signal to the radiation emission unit  201 . Based on the received signal, the radiation emission unit  201  stops emitting the radiation. Then, the image capturing control unit  221  transmits an image capturing control signal to the radiographic imaging apparatus  202 . Then, based on the received image capturing control signal, the radiographic imaging apparatus  202  controls the image output pixels  20211  and the dose detection pixels  20212  to end the conversion of radiation into the dose information signals. 
     In step S 209 , the radiographic imaging apparatus  202  transmits dose information signals Yp, i, and j with respect to each pixel of the image output pixels  20211  after the conversion ends in step S 208  to the image processing unit  223 . Yp is the value of the dose, and i and j are the X-coordinate and the Y-coordinate, respectively, illustrated in  FIG. 5A  similarly to m and n. 
     In step S 210 , the image processing unit  223  performs a gradation process and a noise reduction process on the dose information signals Yp, i, and j with respect to each pixel of the image output pixels  20211  received in step S 209 . Next, the image processing unit  223  transmits the processed signals to the image display device  212 . 
     Next, in step S 211 , the image display device  212  converts received information into a two-dimensional image and displays the two-dimensional image to the operator. Based on the above, the processing of the image capturing of an object ends. 
     In the first exemplary embodiment, the processing from the extraction of defective pixels to the quality determination may be performed when the radiographic imaging system  200  is installed at a use location. In the first exemplary embodiment, the processing from the extraction of defective pixels to the quality determination may be performed periodically such as every month. 
     In the first exemplary embodiment, in step S 106 , the determination may be made using the dispersion or the standard deviation of the coordinates of the defective pixels included in the dose detection pixels  20212  in the dose detection region  2022 . In this case, if the calculated dispersion or standard deviation is less than a criterion value, i.e., if the defective pixels are dense, it may be determined that the radiographic imaging apparatus  202  is a defective product. Similarly, the determination may be made using the dispersion or the standard deviation of the coordinates of the normal pixels included in the dose detection pixels  20212 . 
     The purpose of the determination is as follows. In a case where the defective pixels are dense in a particular portion in the dose detection region  2022 , and even if the geometric center of the normal pixels is close to the center of the dose detection region  2022 , the dose value in the dose detection region  2022  cannot be normally detected. If the dose value cannot be normally detected, the dose value of radiation to be actually emitted to the radiographic imaging apparatus  202  is highly likely to exceed a clinically acceptable value. 
     In the first exemplary embodiment, the dose detection region  2022  is divided into four vertical regions, namely the regions a, b, c, and d. Alternatively, the number of divisions may be changed, and the number of defective pixels may be determined in each region. Alternatively, the direction of divisions may be changed to the horizontal direction or both the vertical and horizontal directions, and the number of defective pixels may be determined in each divided region. 
     In the first exemplary embodiment, in the situation where a determination is made using defective pixels, the determination may be made using normal pixels. For example, in both the determination made by counting the number of defective pixels in step S 401  and the determination made by counting defective pixels in each divided sub-region in step S 403 , the determinations may be made by providing criterion values for the numbers of normal pixels and counting normal pixels. Similarly, in the situation where a determination is made using normal pixels, the determination may be made using defective pixels. For example, in step S 402 , the deviation between the coordinates of the geometric center of the normal pixels in the dose detection region  2022  and the center coordinates of the dose detection region  2022  is obtained. Alternatively, the coordinates of the geometric center of the defective pixels may be used. 
     Only any one of the determination methods described in the first exemplary embodiment, i.e., the determination method in step S 402 , the determination method in step S 403 , and the determination method using the dispersion or the standard deviation of the coordinates of the defective pixels or the normal pixels, may be used. 
     By the above inspection, it can be appropriately determined whether a radiographic imaging apparatus having an automatic exposure control (AEC) function can normally perform radiographic imaging involving the AEC function. 
     Other Exemplary Embodiments 
     The present invention can also be achieved by the process of supplying a program for achieving the above functions to a system or an apparatus via a network or a storage medium, and of causing one or more processors of a computer of the system or the apparatus to read and execute the program. 
     As the storage medium, various storage media such as a flexible disk, an optical disc (e.g., a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc Read-Only Memory (DVD-ROM)), a magneto-optical disc, a magnetic tape, a non-volatile memory (e.g., a Universal Serial Bus (USB) memory), and a read-only memory (ROM) can be used. The program for achieving the above functions may be downloaded via the network and executed by the computer. 
     The present invention is not limited to a case where the functions of the above exemplary embodiments are achieved by executing a program code read by the computer. The present invention also includes a case where based on an instruction from the program code, an operating system (OS) operating on the computer performs a part or all of actual processing, and the functions of the above exemplary embodiments are achieved by the processing. 
     Further, the program code read from the storage medium may be written to a memory included in a function extension board inserted into the computer or a function extension unit connected to the computer. The present invention also includes a case where based on an instruction from the program code, a CPU included in the function extension board or the function extension unit performs a part or all of actual processing, and the above functions are achieved by the processing. 
     According to the present invention, a radiographic imaging system that appropriately determines whether a radiographic imaging apparatus having an AEC function can normally perform radiographic imaging involving the AEC function is provided. 
     Other Embodiment 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)?), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2021-011301, filed Jan. 27, 2021, which is hereby incorporated by reference herein in its entirety.