Radiography system, image processing method, and program

Abstract

To enable obtaining of a long image with preferable visibility even when long imaging is performed with a plurality of radiographic apparatuses having different response characteristics.SOLUTION: A control unit of a console acquires information on response characteristics of a plurality of radiographic apparatuses, and processes a radiographic image captured by at least one of the plurality of radiographic apparatuses 3 on the basis of the acquired information on the response characteristics. Specifically, the control unit performs processing of adjusting image quality of a radiographic image with image quality of another radiographic image. Then, the control unit causes a display unit to display a long image based on the processed radiographic image.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a radiation imaging system, an image processing method, and a program. [Background technology]

[0002] In the medical field, long-length radiography is performed to obtain radiographic images (long-length images) of a relatively wide range, such as the entire spine or the entire length of the lower limbs of a human body. For example, Patent Document 1 describes a technology in which long-length photography is performed by arranging multiple radiation imaging devices, generating a long-length image by combining the radiation images obtained from each of the multiple radiation imaging devices, and performing scattered radiation correction on the long-length image for each imaging location. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-189392 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional long-length imaging is based on the premise that long-length imaging is performed using multiple radiation imaging devices with the same response characteristics. However, when long-length imaging is performed using multiple radiation imaging devices with different response characteristics, there is a problem in that the visibility of the obtained long-length image is poor.

[0005] An object of the present invention is to provide a long image with good visibility even when long-length imaging is performed using a mixture of a plurality of radiation imaging devices with different response characteristics. [Means for solving the problem]

[0006] In order to solve the above problems, a radiation imaging system according to the present invention comprises: a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; A radiography system comprising: an acquisition unit that acquires information about the response characteristics of the plurality of radiation imaging devices; an image processing unit that processes a radiographic image captured by at least one of the plurality of radiographic devices based on information about the response characteristics acquired by the acquisition unit; a display unit that displays a long image based on the plurality of radiation images including the radiation image processed by the image processing unit; Equipped with.

[0007] Further, the image processing method according to the present invention comprises: a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; An image processing method in a radiation imaging system comprising: acquiring information about the response characteristics of the plurality of radiation imaging devices; processing a radiation image captured by at least one of the plurality of radiation imaging devices based on the acquired information about the response characteristics; displaying a long image based on the plurality of radiographic images including the processed radiographic image; Includes:

[0008] In addition, the program according to the present invention is a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; a computer of a radiography system including the an acquisition unit that acquires information about the response characteristics of the plurality of radiation imaging devices; an image processing unit that processes a radiographic image captured by at least one of the plurality of radiographic devices based on the information about the response characteristics acquired by the acquisition unit; a display unit that displays a long image based on the plurality of radiation images including the radiation image processed by the image processing unit; Function as. [Effects of the Invention]

[0009] According to the present invention, even when long-length imaging is performed using a mixture of a plurality of radiation imaging devices with different response characteristics, a long-length image with good visibility can be obtained. [Brief explanation of the drawings]

[0010] Advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for illustrative purposes only and are not intended to limit the scope of the invention. [Figure 1] 1 is a diagram showing the overall configuration of a radiation imaging system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the functional configuration of the console of FIG. 1. [Figure 3] 3 is a diagram showing an example of a target value table stored in a storage unit of FIG. 2. FIG. [Figure 4] FIG. 2 is a block diagram showing the functional configuration of the radiation imaging apparatus of FIG. [Figure 5] 3 is a flowchart showing the flow of a long image generation process executed by the control unit in FIG. 2. [Figure 6] This figure shows how images with pixel sizes of 150 μm and 100 μm are combined into a pixel size of 300 μm by binning processing. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the scope of the invention is not limited to the illustrated examples.

[0012] [Configuration of Radiography System 100] First, the configuration of this embodiment will be described. Fig. 1 is a diagram showing an example of the overall configuration of a radiation imaging system 100 according to this embodiment. As shown in Fig. 1, the radiation imaging system 100 includes a radiation irradiating device 1, a console 2, and a radiation imaging device 3. The console 2 is connected to the radiation irradiating device 1 so as to be able to transmit and receive data. The console 2 is also connected to the radiation imaging device 3 attached to a holder 11a so as to be able to transmit and receive data.

[0013] The radiation irradiator 1 is disposed in a position facing a plurality of radiation imaging devices 3 mounted on a holder 11a of an imaging table 11 across a subject H. The radiation irradiator 1 irradiates radiation to the plurality of radiation imaging devices 3 mounted on the holder 11a via a patient, who is the subject H, based on radiation irradiation conditions input from a console 2. The radiation irradiation conditions input from the console 2 include, for example, a tube current value, a tube voltage value, radiation irradiation time, a mAs value, and a SID. In this embodiment, the radiation irradiator 1 irradiates radiation to the multiple radiation imaging devices 3 attached to the holder 11a in a single irradiation, but the present invention is not limited to this. For example, the radiation irradiator 1 may be configured to irradiate radiation individually to the multiple radiation imaging devices 3 by changing the orientation of the tube. Alternatively, the radiation irradiator 1 may be configured to irradiate radiation individually to the multiple radiation imaging devices 3 by moving the tube.

[0014] The imaging table 11 is configured so that multiple radiation imaging devices 3 can be mounted in the holder 11a so that they are aligned vertically with some of them overlapping each other. In this embodiment, the radiation imaging device 3 mounted in the upper row of the holder 11a is referred to as radiation imaging device 3A. The radiation imaging device 3 mounted in the middle row of the holder 11a is referred to as radiation imaging device 3B. The radiation imaging device 3 mounted in the lower row of the holder 11a is referred to as radiation imaging device 3C. In this embodiment, the radiation imaging devices 3A to 3C have different response characteristics. The holder 11a has a detection unit that detects ID information of the radiation imaging devices 3A to 3C mounted in each of the upper, middle, and lower rows. For example, the holder 11a has a barcode reader in each row, and detects the ID information of the radiation imaging devices 3A to 3C by reading barcodes indicating ID information affixed to the radiation imaging devices 3A to 3C. The holder 11a transmits the ID information detected in each row to the console 2. Note that the above-described method of detecting ID information is merely an example and is not particularly limited. 1, the present embodiment will be described with reference to a case where the holder 11a of the imaging table 11 is configured to be able to mount three radiation imaging devices, but the present invention is not limited to a case where the number of radiation imaging devices mounted on the imaging table 11 is three. The number of radiation imaging devices mounted on the imaging table 11 may be two, four or more.

[0015] The console 2 outputs radiation irradiation conditions to the radiation irradiating device 1 to control radiation irradiation. The console 2 also outputs image reading conditions to the radiation imaging devices 3A to 3C to control the operation of reading radiation images. The console 2 also functions as an image processing device, performing image processing on the radiation images generated by the radiation imaging devices 3A to 3C. For example, the console 2 acquires information on the response characteristics of each of the radiation imaging devices 3A to 3C, and processes the radiation image acquired by at least one of the radiation imaging devices 3A to 3C based on the acquired information on the response characteristics. This makes the image quality of the generated multiple radiation images consistent due to the response characteristics. The console 2 then synthesizes the multiple radiation images to generate a long image.

[0016] Here, the information relating to the response characteristics of the radiation imaging device 3 is an index value indicating the response characteristics of the radiation imaging device 3. Examples of information relating to the response characteristics include DQE (Detective Quantum Efficiency), MTF (Modulation Transfer Function), pixel size, etc. DQE is detective quantum efficiency, and is an index indicating the ratio of a signal that can be output relative to an incident dose. The higher the DQE, the better the response and the better the image quality of the resulting radiation image. MTF is an index indicating sharpness. The higher the MTF, the sharper the resulting radiation image. Pixel size is an index indicating fineness. The smaller the pixel size, the finer the radiation image.

[0017] As shown in FIG. 2, the console 2 comprises a control unit 21, a storage unit 22, an operation unit 23, a display unit 24, and a communication unit 25, and each unit is connected by a bus .

[0018] The control unit 21 is composed of a CPU (Central Processing Unit), RAM (Random Access Memory), etc. In response to operations on the operation unit 23, the CPU of the control unit 21 reads out system programs and various processing programs stored in the storage unit 22, loads them into the RAM, and performs centralized control of the operations of the various units of the console 2 according to the loaded programs. The CPU of the control unit 21 also controls the radiation irradiation operation of the radiation irradiation device 1 and the reading operation of the radiation imaging device 3. The CPU of the control unit 21 also executes long image generation processing A (described later) and the like, using radiation images transmitted from the radiation imaging devices 3A to 3C. In this embodiment, the control unit 21 functions as an acquisition unit and an image processing unit.

[0019] The storage unit 22 is configured with a non-volatile semiconductor memory, a hard disk, etc. The storage unit 22 stores various programs executed by the control unit 21, parameters required for executing processes by the programs, data such as processing results, etc. The various programs are stored in the storage unit 22 in the form of readable program code. The control unit 21 sequentially executes operations in accordance with the program code. The storage unit 22 also stores radiation irradiation conditions and image reading conditions corresponding to the imaging region. Furthermore, the storage unit 22 stores imaging order information transmitted from a RIS (Radiology Information System) or the like (not shown). The imaging order information includes patient information and examination information. The examination information includes an examination ID, imaging region, examination date, etc. The imaging region may be the imaging region of the entire long image, or may be the imaging region of each image obtained by the radiation imaging devices 3A to 3C.

[0020] The storage unit 22 also stores the ID information and address information (such as IP address) of each of the radiation imaging devices 3 used in the radiation imaging system 100 in association with each other.

[0021] The storage unit 22 also stores a target value table 221. As shown in Fig. 3, the target value table 221 stores combinations of values ​​of information relating to response characteristics (DQE, MTF, pixel size) in association with values ​​of information relating to response characteristics that serve as targets (standards) for aligning the image quality of radiographic images obtained by the radiographic imaging apparatuses 3A to 3C of that combination. The target DQE may be the highest DQE among the DQEs of the radiation imaging apparatuses 3A to 3C, or the lowest DQE among the DQEs of the radiation imaging apparatuses 3A to 3C. Alternatively, it may be a DQE between the highest and lowest DQEs. The target MTF may be the highest MTF among the MTFs of the radiation imaging apparatuses 3A to 3C, or the lowest MTF among the MTFs of the radiation imaging apparatuses 3A to 3C. Alternatively, it may be an MTF between the highest and lowest MTFs. The target pixel size may be, for example, the least common multiple of the pixel sizes of the radiation imaging apparatuses 3A to 3C. However, since the larger the pixel size, the more information is lost. Therefore, for example, when the least common multiple of the pixel sizes of the radiation imaging apparatuses 3A to 3C is equal to or greater than a predetermined threshold value, or when the pixel size is sufficient for diagnosis without adjustment, pixel size adjustment may be omitted.

[0022] The operation unit 23 includes a keyboard having cursor keys, numeric input keys, and various function keys, and a pointing device such as a mouse. The operation unit 23 outputs instruction signals input by operating the keyboard or the mouse to the control unit 21. The operation unit 23 may also be a touch screen provided on the display screen of the display unit 24. In this case, the operation unit 23 outputs instruction signals input via the touch screen to the control unit 21. The operation unit 23 also includes an exposure switch for instructing the radiation irradiator 1 to perform dynamic imaging.

[0023] The display unit 24 is composed of a monitor such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube). The display unit 24 displays various input screens, processed radiographic images (long images), etc. in accordance with instructions of display signals input from the control unit 21. The display unit 24 functions as a display unit and a notification unit.

[0024] The communication unit 25 transmits and receives data to and from the radiation irradiating device 1 and the radiation imaging devices 3A to 3C attached to the holder 11a. Note that the communication between the console 2 and the radiation irradiating device 1 and the radiation imaging device 3 may be wired or wireless. The communication unit 25 includes a LAN adapter, a modem, a TA (Terminal Adapter), and the like, and controls data transmission and reception with a RIS (not shown) and the like connected to the communication network.

[0025] The radiation imaging device 3 is composed of a semiconductor image sensor such as an FPD (Flat Panel Detector). The radiation imaging device 3 is attached to a holder 11a of an imaging table 11, and faces the radiation irradiator 1 across the subject H. The radiation imaging device 3 detects radiation (X-rays) that has been irradiated from the radiation irradiator 1 and passed through at least the subject H, according to its intensity, and obtains image data (radiation image) according to the detected radiation.

[0026] 4 is a block diagram showing the functional configuration of the radiation imaging device 3. The radiation imaging device 3 is configured to include a control unit 31, a storage unit 32, a radiation detection unit 33, and a communication unit 34, and each unit is connected via a bus 35.

[0027] The control unit 31 is configured with a CPU (Central Processing Unit), RAM (Random Access Memory), etc. The CPU of the control unit 31 reads out the system program and various processing programs stored in the storage unit 32, expands them in the RAM, and performs centralized control of the operations of each unit according to the expanded programs.

[0028] The storage unit 32 is configured with a non-volatile semiconductor memory, a hard disk, etc. The storage unit 32 stores various programs executed by the control unit 31, parameters required for executing processes by the programs, data such as processing results, etc. The various programs are stored in the storage unit 32 in the form of readable program code. The control unit 31 sequentially executes operations in accordance with the program code. The storage unit 32 also stores ID information and information relating to response characteristics of the radiation imaging apparatus 3 (its own apparatus).

[0029] The radiation detection unit 33 is configured with a matrix of multiple detection elements (pixels) that detect radiation irradiated from the radiation irradiator 1 and transmitted through at least the subject H according to its intensity, convert the detected radiation into an electrical signal, and store the signal. Each pixel has a switching unit such as a TFT (Thin Film Transistor). The radiation detection unit 33 acquires image data by reading the electrical signal stored in each pixel under the control of the switching unit of each pixel based on image reading conditions input from the console 2. The radiation detection unit 33 then attaches ID information to the acquired image data and outputs it to the console 2.

[0030] The communication unit 34 transmits and receives data to and from the console 2. The communication with the console 2 may be wired communication or wireless communication.

[0031] [Operation of the Radiography System 100] Next, the operation of the radiation imaging system 100 will be described. When performing long-length imaging in the radiation imaging system 100, the imaging implementer mounts the radiation imaging devices 3A to 3C in the holder 11a, and then operates the operation unit 23 on the console 2 to select imaging order information for the imaging target. When the radiation imaging devices 3A to 3C are attached, the imaging stand 11 detects the ID information of the radiation imaging devices 3A to 3C attached to each stage of the holder 11a, and transmits the ID information detected for each stage to the console 2. The control unit 21 of the console 2 stores the ID information detected for each stage in RAM in association with the top, middle, or bottom position. When the imaging order information for long imaging is selected by operating the operation unit 23 on the console 2, the control unit 21 executes the long image generation process.

[0032] 5 is a flowchart showing the flow of the long image generation process executed by the control unit 21 in the console 2. The long image generation process will be described below with reference to FIG.

[0033] First, the control unit 21 acquires information about the response characteristics of the radiation imaging devices 3A to 3C attached to each stage of the holder 11a (step S1). For example, the control unit 21 requests and acquires information relating to response characteristics from each of the radiation imaging apparatuses 3A to 3C. In this embodiment, the control unit 21 acquires DQE, MTF, and pixel size as information relating to response characteristics.

[0034] Next, the control unit 21 sets the imaging conditions based on the selected imaging order information (step S2). For example, the control unit 21 determines the imaging conditions (radiation irradiation conditions and image reading conditions) based on the imaging region and the like included in the imaging order information. The imaging conditions may be determined based on information on the response characteristics of the radiation imaging devices 3A to 3C. The control unit 21 transmits the determined radiation irradiation conditions to the radiation irradiating device 1 via the communication unit 25. The control unit 21 also transmits the image reading conditions to the radiation imaging devices 3A to 3C via the communication unit 25.

[0035] Next, the control unit 21 determines whether or not radiation irradiation has been instructed by the exposure switch of the operation unit 23 (step S3). If it is determined that radiation irradiation has not been instructed (step S3; NO), the control unit 21 returns to step S3. If it is determined that radiation irradiation has been instructed (step S3; YES), the control unit 21 causes the radiation irradiating device 1 and the radiation imaging devices 3A to 3C to perform long-length imaging (step S4) and acquire multiple radiation images (step S5). The radiation irradiating device 1 irradiates radiation in accordance with the instruction from the console 2. The control units 31 of the radiation imaging devices 3A to 3C each detect and accumulate radiation using the radiation detection units 33, and read out the accumulated radiation to generate radiation images. Then, the control units 31 of the radiation imaging devices 3A to 3C each associate the generated radiation images with ID information and transmit them to the console 2 via the communication units 34.

[0036] Next, the control unit 21 executes a process for adjusting the image quality of the radiographic images acquired from the radiographic apparatuses 3A to 3C based on the information relating to the response characteristics acquired in step S1 (step S6). In step S6, the control unit 21 performs a process of adjusting the image quality of the plurality of radiographic images acquired from the radiography devices 3A to 3C based on the information on the response characteristics acquired in step S1 so that the image quality is consistent. That is, the control unit 21 performs a process of adjusting the image quality of at least one radiographic image to be consistent with the image quality of the other radiographic images based on the information on the acquired response characteristics.

[0037] For example, the control unit 21 performs binning (pixel addition) on at least one radiographic image based on information related to the pixel sizes of the radiographic devices 3A to 3C, and adjusts the pixel sizes of the radiographic images acquired from the radiographic devices 3A to 3C so that they are uniform. Binning processing is processing for integrating multiple pixels into one pixel. For example, the control unit 21 refers to the target value table 221 in the storage unit 22 and identifies a target pixel size for adjustment based on the combination of pixel sizes of the radiation imaging devices 3A to 3C. Then, the control unit 21 integrates (adds or averages) pixel values ​​of multiple adjacent pixels for at least one of the acquired radiographic images so that the pixel size of each radiographic image becomes the target pixel size. For example, as shown in FIG. 6, when images with pixel sizes of 150 μm and 100 μm are integrated into a pixel size of 300 μm by binning processing, the control unit 21 integrates four adjacent pixels in the image with a pixel size of 150 μm. Furthermore, the control unit 21 integrates nine adjacent pixels in the image with a pixel size of 100 μm. Alternatively, the control unit 21 may perform a reduction or enlargement process on at least one of the radiographic images acquired from the radiographic imaging devices 3A to 3C based on the information on the pixel size acquired in step S1 so that the pixel sizes of the radiographic images are uniform.

[0038] Furthermore, the control unit 21 adjusts the sharpness of at least one radiographic image based on information relating to the MTF of the radiographic apparatuses 3A to 3C, so that the sharpness of the radiographic images acquired from the radiographic apparatuses 3A to 3C is uniform. For example, the control unit 21 refers to the target value table 221 in the storage unit 22 and specifies the target MTF for adjustment based on the combination of the MTFs of the radiation imaging devices 3A to 3C. Then, the control unit 21 performs sharpness adjustment processing on at least one of the radiation images acquired from the radiation imaging devices 3A to 3C so that the MTF of each radiation image becomes the target MTF. For example, convolution processing using a filter can be used as a sharpness adjustment process. Because the signal and noise change by the same amount, it is possible to adjust to the target MTF without changing the DQE.

[0039] Furthermore, the control unit 21 adjusts the gain of at least one radiographic image based on information relating to the DQE of the radiographic apparatuses 3A to 3C, and adjusts the image quality of the radiographic images acquired from the radiographic apparatuses 3A to 3C so that they are uniform. For example, the control unit 21 refers to the target value table 221 in the storage unit 22 and identifies a DQE to be adjusted based on the combination of DQEs of the radiation imaging devices 3A to 3C. Then, the control unit 21 performs gain adjustment processing on at least one of the radiation images acquired from the radiation imaging devices 3A to 3C so that the DQE of each radiation image becomes the target DQE. For example, gain correction data adjusted in advance so that the radiographic image after gain adjustment has a target DQE is stored for each radiographic apparatus 3 used in the radiographic system 100. The gain correction data is data of correction coefficients for each pixel of the radiographic image obtained by each radiographic apparatus 3 when radiation is uniformly irradiated. The control unit 21 performs gain adjustment processing on the radiographic images obtained from each of the radiographic apparatuses 3A to 3C using the gain correction data according to the target DQE.

[0040] After the adjustment of the response characteristics is completed, the control unit 21 synthesizes (combines) the multiple radiation images acquired from the radiation imaging devices 3A to 3C to generate a long image (step S7). Before or after combining, the control unit 21 may correct density differences that occur due to the relative positions of the radiation imaging devices 3A to 3C. For example, since the radiation dose reaching the radiation imaging device 3 at the back is reduced by the radiation imaging device 3 at the front relative to the tube, the control unit 21 adds a density value corresponding to the reduced radiation dose to the pixel value of the radiation image of the radiation imaging device 3 at the back. Furthermore, the control unit 21 corrects any reflection of the board portion of the radiation imaging device overlapping in front. Furthermore, when radiography is performed using the radiation imaging devices 3A to 3C with different pixel sizes, the control unit 21 unifies the image sizes before generating a long image.

[0041] Next, the control unit 21 performs image processing on the generated long image (step S8). The control unit 21 performs image processing such as tone correction, frequency emphasis, and scattered radiation correction on the long image.

[0042] Next, the control unit 21 causes the display unit 24 to display the long image that has undergone image processing (step S9), and ends the long image generation process.

[0043] In this way, the control unit 21 performs processing to align the image quality of multiple radiation images acquired from the radiation imaging devices 3A to 3C based on information about the response characteristics of the radiation imaging devices 3A to 3C. Therefore, even when long-length imaging is performed using a mixture of multiple radiation imaging devices 3 with different response characteristics, long-length images with good visibility can be obtained. Furthermore, since long-length imaging is possible using a mixture of radiation imaging devices 3 with different response characteristics, the user does not need to purchase multiple radiation imaging devices 3 with the same response characteristics, improving convenience.

[0044] <Variation 1> In the above embodiment, an example has been described in which the image quality of a radiographic image is adjusted based on the information relating to response characteristics at the console 2. However, the process of adjusting the image quality of a radiographic image based on the information relating to response characteristics may be performed at each of the radiographic apparatuses 3A to 3C.

[0045] For example, in step S1 of the long image generation processing shown in Fig. 5, when information on response characteristics is acquired from each of the radiation imaging apparatuses 3A to 3C, the control unit 21 derives target MTF, DQE, and pixel size based on the acquired information. The control unit 21 transmits the derived MTF, DQE, and pixel size to the radiation imaging apparatuses 3A to 3C via the communication unit 25. The control unit 31 of each of the radiation imaging apparatuses 3A to 3C performs image processing such as sharpness adjustment, gain adjustment, and binning on the radiation image generated by long imaging so that the radiation image matches the target MTF, DQE, and pixel size received from the console 2. The control unit 31 transmits the processed radiation image to the console 2 via the communication unit 25. When the console 2 receives the radiation image via the communication unit 25, the control unit 21 combines the received radiation images to generate a long image, performs image processing such as gradation correction, and displays the image on the display unit 24.

[0046] <Variation 2> In the above embodiment, the DQEs of multiple radiographic images are made uniform by performing gain adjustment processing on the radiographic images obtained by imaging, but the DQE adjustment method is not limited to this. For example, when the radiation irradiator 1 irradiates the radiographic imaging devices 3A to 3C individually with radiation three times by changing the tube angle, the control unit 21 may adjust the radiation dose irradiated by the radiation irradiator 1 to each of the radiographic imaging devices 3A to 3C according to the DQE. For example, when irradiating the radiographic imaging device 3 with a low DQE, the control unit 21 sets the imaging conditions so that a higher radiation dose is irradiated than when irradiating the radiographic imaging device 3 with a higher DQE. The same applies when the radiation irradiator 1 irradiates the radiographic imaging devices 3A to 3C individually with radiation three times by changing the tube position.

[0047] When adjusting the DQE by adjusting the radiation dose, it is preferable to adjust the DQE to the lowest DQE among the DQEs of the radiation imaging devices 3A to 3C within a range that does not affect diagnosis, from the viewpoint of reducing radiation exposure dose.

[0048] Furthermore, when the radiation irradiating device 1 irradiates radiation to the radiation imaging devices 3A to 3C at once by irradiating radiation once, the mounting positions of the radiation imaging devices 3A to 3C may be adjusted so that the SID of the radiation imaging device 3 with the lowest DQE is shortened. The SID is the distance between the tube and the radiation imaging device 3. For example, the control unit 21 issues a notification urging the radiation imaging devices 3A to 3C to be mounted so that the radiation imaging device 3 with the lowest DQE is positioned in the middle where the SID is shortest.

[0049] <Variation 3> In the above embodiment, it has been described that information relating to the response characteristics of the radiation imaging apparatus 3 is stored in the storage unit 32 of the radiation imaging apparatus 3, and that the console 2 acquires this information from the radiation imaging apparatus 3. Alternatively, information relating to the response characteristics of the radiation imaging apparatus 3 may be stored in the storage unit 22 of the console 2 in association with ID information of the radiation imaging apparatus 3. Then, in step S1 of the long image generation processing, the information relating to the response characteristics may be read out and acquired from the storage unit 22.

[0050] <Variation 4> In the above embodiment and modified examples, the control unit 21 has been described as performing a process for aligning the image quality of a plurality of radiographic images separately from the final image processing (step S9) in the console 2. However, the above-described process may not be performed, and the visibility of the long image may be improved by frequency enhancement processing in the final image processing in the console 2. The frequency enhancement processing may be performed on each of the plurality of radiographic images using parameters according to the response characteristics of each radiographic device 3 before combining the radiographic images. Alternatively, after combining the radiographic images, frequency enhancement processing may be performed on each of the regions of the radiographic device 3 in the long image using parameters according to the response characteristics of the radiographic device 3.

[0051] <Variation 5> In the above embodiment, when the pixel sizes of the radiation imaging devices 3A to 3C are different, the image is acquired at the original pixel size, and the pixel size is adjusted by image processing in the console 2. Alternatively, the control unit 21 may adjust the pixel size by adjusting the binning number (number of pixels added) when the radiation imaging devices 3A to 3C acquire the image. For example, the control unit 21 of the console 2 calculates the least common multiple of the pixel sizes of the radiation imaging devices 3A to 3C and sets the image reading conditions (number of pixels added) for the radiation imaging devices 3A to 3C so that the image is acquired at the pixel size of the least common multiple. For example, as shown in FIG. 6, when the pixel sizes are 150 μm and 100 μm, a radiation imaging device with a pixel size of 150 μm acquires an image at a pixel size of 300 μm by 2×2 binning. A radiation imaging device with a pixel size of 100 μm acquires an image at a pixel size of 300 μm by 3×3 binning. This eliminates the need to adjust the pixel size of the radiation image.

[0052] <Other variations> In addition, the following modifications may be implemented. (1) When radiography is performed using radiographic imaging devices 3A to 3C with different pixel sizes, the control unit 21 selects the binning number (number of pixels added) so that the pixel sizes are close to each other and the data volume is small. For example, when pixel sizes of 100 μm and 150 μm are mixed, the binning number is set to 2 for radiographic images with 100 μm pixel sizes and no binning is performed for radiographic images with 150 μm pixel sizes. Furthermore, when pixel sizes of 125 μm and 150 μm are mixed, no binning is performed for radiographic images with either pixel size. Alternatively, no binning may be selected for all pixel size combinations, with priority given to image quality. Whether or not no binning is performed for all combinations with priority given to image quality may be set by the user by operating the operation unit 23.

[0053] (2) When radiography is performed using the radiation imaging devices 3A to 3C with different pixel sizes, the control unit 21 performs interpolation processing to match the pixel size to that of the radiation imaging device 3 with the coarsest pixel size.

[0054] (3) Depending on the pixel size, the radiation imaging device 3 may have compatible grids or incompatible grids. For example, a radiation imaging device 3 with a pixel size of 150 μm only supports a 40-line grid, while a radiation imaging device 3 with a pixel size of 100 μm supports 30, 40, or 60-line grids. Therefore, the control unit 21 determines the type (number) of grids installed on the imaging table 11 corresponding to the radiation imaging devices 3A to 3C, and outputs a notification (warning) if it determines that a grid of a type incompatible with the pixel size is installed. For example, if a radiation imaging device 3 with a pixel size of 150 μm is attached to an imaging table 11 with 60 grids installed on each of the upper, middle, and lower rows and an attempt is made to perform imaging, the control unit 21 outputs a warning that an incompatible grid is installed on the radiation imaging device 3. The notification can be, for example, displayed on the display unit 24 or output as an audio message. This prevents imaging from being performed using an incompatible grid. As a method for identifying the type of grid installed corresponding to the radiation imaging devices 3A to 3C, for example, each stage of the holder 11a is provided with a detection means for detecting the type of grid attached thereto, and the control unit 21 identifies the type of grid based on a signal from the detection means. For example, each grid is provided with a barcode indicating the grid type, and the holder 11a detects the type of grid attached to each stage by reading the barcode on the grid attached to each stage. The holder 11a transmits the grid type detected for each stage to the console 2. The storage unit 22 of the console 2 stores a table linking the pixel size of the radiation imaging device 3 with the grid type corresponding to that pixel size. The control unit 21 determines whether a grid of a type corresponding to the pixel size is installed based on the type of grid attached to each stage of the imaging table and the pixel size of the radiation imaging device 3.

[0055] (4) When the basic image quality of the radiation imaging devices 3A to 3C is different from one another, the control unit 21 may adjust image processing parameters such as gradation correction processing for each radiation image (each radiation imaging device 3) so that the visibility of each image becomes similar.

[0056] (5) The console 2 may be provided with a machine learning model for erasure processing to erase predetermined structures, such as screws inside the radiation imaging device 3, that appear in the radiation image for each type of radiation imaging device 3. The control unit 21 of the console 2 may then switch the machine learning model to be used depending on the type of radiation imaging device 3 that is the sender of the radiation image received from the radiation imaging device 3, and perform the erasure processing.

[0057] (6) The appearance of screw holes in a radiographic image may differ depending on the type of radiographic device. Therefore, the control unit 21 switches between multiple screw hole removal processes for each radiographic image depending on the combination, arrangement, and overlapping of the types of radiographic devices 3A to 3C attached to the holder 11a. Note that the screw hole removal process may use a machine learning model as described above.

[0058] (7) The saturation dose, which is the upper limit dose, differs for each type of radiation imaging device 3. Therefore, when the saturation doses of the radiation imaging devices 3A to 3C differ, the control unit 21 of the console 2 may adjust (set) the radiation dose irradiated by the radiation irradiating device 1 to match that of the radiation imaging device 3 with the lowest saturation dose. Note that, for example, if information about the saturation dose is stored in the storage unit 22 in association with the ID information of each radiation imaging device 3, the control unit 21 can easily identify the information about the saturation dose of the attached radiation imaging device 3A to 3C based on the ID information.

[0059] (8) If a grid is used during imaging, grid stripes will be drawn on the radiation image. Therefore, when a grid is used during imaging, it is preferable that the control unit 21 of the console 2 perform grid moiré removal processing to remove the grid stripes. To perform grid moiré removal processing, it is necessary to specify the number and orientation of the grid. However, specifying the number and orientation of each grid used for long-length imaging is cumbersome. Therefore, grids with a predetermined number and orientation are installed on each stage of the holder 11a, and when performing grid moiré removal processing on a radiation image, the control unit 21 performs grid moiré removal processing on grids with a predetermined number and orientation. The grid moiré removal process is preferably performed at a predetermined timing, for example, after the defective pixel correction and before the screw hole removal process.

[0060] (9) When combining radiographic images obtained by long-length imaging, the user may be notified of the radiographic imaging devices 3 that are recommended to be attached to each stage of the holder 11a so that the joining parts (joints) look as natural as possible. For example, the control unit 21 of the console 2 may display, on the display unit 24, the pixel sizes and ID information, etc., of the radiographic imaging devices 3 that are recommended to be attached to each stage of the holder 11a. For example, it is preferable to recommend that the pixel sizes of adjacent radiographic imaging devices 3 in the upper, middle, and lower stages be similar. Alternatively, the radiographic imaging devices 3 recommended for attachment to each stage of the holder 11a may be notified so that a radiographic imaging device 3 with good image quality is assigned to the stage (position) of the holder 11a corresponding to the region of interest. For example, the control unit 21 of the console 2 causes the display unit 24 to display the pixel size, ID information, etc. of the radiographic imaging devices 3 recommended for attachment to each stage of the holder 11a. The stage (position) corresponding to the region of interest can be identified, for example, based on the body part to be imaged.

[0061] (10) In order to reduce the radiation dose to the patient, it is preferable that the control unit 21 determines the radiation irradiation conditions in accordance with the image quality performance of the radiation imaging device 3. For example, when a high-image-quality radiation imaging device 3 is used, it is preferable to reduce the radiation dose compared to when a low-image-quality radiation imaging device 3 is used.

[0062] (11) When performing calibration before imaging, parameters may be adjusted for each radiation imaging apparatus 3. Furthermore, imaging conditions during calibration may be changed for each radiation imaging apparatus 3.

[0063] As described above, the radiation imaging system 100 includes a plurality of radiation imaging devices 3 with different response characteristics, and a console 2 that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices 3. The control unit 21 of the console 2 acquires information related to the response characteristics of the plurality of radiation imaging devices 3, and processes the radiation image captured by at least one of the plurality of radiation imaging devices 3 based on the acquired information on the response characteristics. Specifically, the control unit 21 executes processing to adjust the image quality of the radiation image to match the image quality of the other radiation images. The control unit 21 then causes the display unit 24 to display a long image based on the processed radiation image.

[0064] Therefore, even when long-length imaging is performed using a mixture of multiple radiation imaging devices 3 with different response characteristics, a long-length image with good visibility can be obtained. Furthermore, since long-length imaging is possible using a mixture of radiation imaging devices 3 with different response characteristics, the user does not need to purchase multiple radiation imaging devices 3 with the same response characteristics, improving convenience.

[0065] The above-described embodiments and modifications are preferred examples of the present invention, and the present invention is not limited to these.

[0066] For example, in the above description, examples have been disclosed in which a hard disk or a semiconductor nonvolatile memory is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to these examples. Other computer-readable media include portable recording media such as CD-ROMs. Furthermore, carrier waves are also applicable as a medium for providing data for the program according to the present invention via a communication line.

[0067] While embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are made for purposes of illustration and example only, and not limitation, the scope of the invention being to be construed by the appended claims. [Explanation of symbols]

[0068] 100 Radiography System 1 Radiation irradiation device 11. Photo stand 11a holder 2 Console 21 Control section 22 Memory section 23 Control section 24 Display section 25 Communications Department 26 Bus 3. Radiography equipment 31 Control Unit 32 Storage section 33 Radiation detection unit 34 Communications Department

Claims

1. a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; A radiography system comprising: an acquisition unit that acquires information about the response characteristics of the plurality of radiation imaging devices; an image processing unit that processes a radiographic image captured by at least one of the plurality of radiographic devices based on information about the response characteristics acquired by the acquisition unit; a display unit that displays a long image based on the plurality of radiation images including the radiation image processed by the image processing unit; A radiography system comprising:

2. The radiation imaging system according to claim 1 , wherein the image processing unit performs processing to adjust the image quality of the radiation image to match the image quality of other radiation images of the plurality of radiation images based on the information about the response characteristics acquired by the acquisition unit.

3. the information about the response characteristics is information about an MTF (Modulation Transfer Function), The radiation imaging system according to claim 1 , wherein the image processing unit adjusts the sharpness of the radiation image based on the information relating to the MTF acquired by the acquisition unit.

4. the information on response characteristics is information on DQE (Detective Quantum Efficiency), The radiation imaging system according to claim 1 , wherein the image processing unit adjusts a gain of the radiation image based on the information on the DQE acquired by the acquisition unit.

5. the information on response characteristics is information on DQE (Detective Quantum Efficiency), The radiation imaging system further includes a control unit that controls a radiation irradiation device that irradiates radiation, The radiation imaging system according to claim 1 , wherein the control unit adjusts the radiation dose irradiated by the radiation irradiation device based on the information on the DQE acquired by the acquisition unit.

6. the information about the response characteristics is information about a pixel size, The radiation imaging system according to claim 1 , wherein the image processing unit performs pixel addition on the radiation image based on the information about the pixel size acquired by the acquisition unit.

7. the information about the response characteristics is information about a pixel size, The radiation imaging system further includes a control unit that controls the radiation imaging device, The radiation imaging system according to claim 1 , wherein the control unit adjusts the number of pixels to be added when the radiation imaging apparatus acquires an image based on the information about the pixel size acquired by the acquisition unit.

8. the information about the response characteristics is information about pixel sizes of the plurality of radiation imaging devices, The radiation imaging system further includes a discrimination unit that discriminates types of grids installed corresponding to the plurality of radiation imaging devices; a notification unit that notifies the user when a grid type that does not correspond to the pixel size is set as a result of the determination by the determination unit; The radiation imaging system according to claim 1 , comprising:

9. the information about the response characteristic is information about a saturation dose, The radiation imaging system further includes a control unit that controls a radiation irradiation device that irradiates radiation, The radiation imaging system according to claim 1 , wherein the control unit adjusts the radiation dose of the radiation irradiation device based on the information about the saturation dose acquired by the acquisition unit.

10. a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; An image processing method in a radiation imaging system comprising: acquiring information about the response characteristics of the plurality of radiation imaging devices; processing a radiation image captured by at least one of the plurality of radiation imaging devices based on the acquired information about the response characteristics; displaying a long image based on the plurality of radiographic images including the processed radiographic image; An image processing method comprising:

11. a plurality of radiation imaging devices each having a different response characteristic; and an image processing device that generates a long image by combining a plurality of radiation images captured by the plurality of radiation imaging devices; a computer of a radiography system including the an acquisition unit that acquires information about the response characteristics of the plurality of radiation imaging devices; an image processing unit that processes a radiographic image captured by at least one of the plurality of radiographic devices based on the information about the response characteristics acquired by the acquisition unit; a display unit that displays a long image based on the plurality of radiation images including the radiation image processed by the image processing unit; A program to function as a

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