Dynamic quality control device, dynamic quality control program, and dynamic quality control method

Abstract

To properly perform quality management of dynamic state imaging consisting of a plurality of frame images.SOLUTION: A dynamic state quality management device 2 for performing quality management about dynamic state imaging of imaging a dynamic state of a subject by irradiating the subject with radiation comprises: generation means which determines a frame image being an object of quality management from a plurality of frame images constituting a dynamic state image obtained by dynamic state imaging and generates information about quality of the dynamic state imaging using the determined frame image (at least one of information indicating a low contrast resolution of the dynamic state image and information indicating presence / absence of at least one of stripes and irregularities); and output means which outputs information about the quality of the dynamic state imaging.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a dynamic quality control device, a dynamic quality control program, and a dynamic quality control method. [Background technology]

[0002] Conventionally, various techniques have been proposed for quality control (QC) and quality assurance (QA) related to radiography of still images. For example, Patent Document 1 describes a radiographic image reading system that evaluates display dimensional accuracy, linearity, sharpness, etc. by performing calculations on image data obtained by radiography of a quality control phantom, determines whether the evaluation result for each evaluation item exceeds a threshold value, and determines whether each evaluation item passes or fails based on the results of the determination. Furthermore, Non-Patent Document 1 describes a quality control program that takes an image of a QC phantom, analyzes all test items including system sensitivity by automatic calculation, determines whether the value obtained by the calculation is within or outside the control range, and notifies the user of the result of the determination. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-283531 [Non-patent literature]

[0004] [Non-Patent Document 1] Tsuyoshi Haraguchi, "Development of CR Quality Control Program "SimpleCheck QC"", KONICA MINOLTA TECHNOLOGY REPORT, 2009, Vol. 6, pp. 69-72 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, various devices have been developed for performing dynamic radiography, which generates dynamic images made up of a plurality of frame images by sequentially irradiating radiation. As with still imaging, it is desirable for dynamic radiography to have a certain level of quality in order to prevent problems such as misdiagnosis by doctors, increased workload for technicians due to retakes, and increased radiation exposure for patients due to retakes. However, because dynamic radiography is a technology that has only recently been used in medical settings, there has not been sufficient research and development into QC and QA for dynamic radiography. For example, much of the regular QC after product delivery is performed manually and subjectively by engineers, but because dynamic photography provides a wider range of QC information than still photography, improvements in work efficiency are desired.

[0006] Furthermore, while still photography only captures one frame image, dynamic photography captures multiple frames in succession, which means that the radiation source cannot be cooled sufficiently due to the longer radiation exposure time, and the temperature of the radiation source may rise due to the trapped heat. As the temperature of the radiation source increases, the dose of radiation emitted by the radiation source increases or decreases over time (dose fluctuation), resulting in a problem in that the pixel values ​​read by the radiation detector based on the dose also increase or decrease. As described above, problems specific to dynamic photography can arise when performing dynamic photography. However, the number of frame images that make up one dynamic image can reach several hundred, and it is necessary to check the quality of all the frame images. It takes too much time to check.

[0007] Furthermore, in dynamic imaging, there is an idea to apply quality control for still image imaging, for example, to perform quality control on an averaged image obtained by averaging a plurality of frame images. However, such quality control does not allow for accurate evaluation of, for example, low-contrast resolution (how finely objects with different radiation absorption can be distinguished). Specifically, for safety reasons, the evaluation of low contrast resolution must be based on the minimum value rather than the average value, but if multiple frame images are averaged, the noise components are also averaged, making it impossible to obtain the minimum value. Furthermore, when quality control is performed using images obtained by dynamic imaging of a dynamic phantom, the averaged image will contain residual images of the metal disc 62b and dial 62c attached to the movable member 62 of the dynamic phantom 6, as shown in Figure 3(b), making it difficult to perform accurate evaluation.

[0008] The present invention has been made in view of the above-mentioned problems, and has as its object to enable appropriate quality control of dynamic photography consisting of a plurality of frames. [Means for solving the problem]

[0009] In order to solve the above problems, the dynamic quality control device according to the present invention comprises: A dynamic quality control device for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: a generation means for determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; an output means for outputting information relating to the quality of the dynamic radiography; Equipped with The frame image to be subjected to the quality control is This is a frame image between the middle and the end. , The information regarding the quality of the dynamic imaging includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks.

[0010] In addition, the dynamic quality control program according to the present invention includes: A dynamic quality control program for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: On the computer, a process of determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; a process of outputting information relating to the quality of the dynamic imaging; Execute The frame image to be subjected to the quality control is This is a frame image between the middle and the end. , The information regarding the quality of the dynamic imaging includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks.

[0011] Further, the dynamic quality control method according to the present invention comprises: 1. A dynamic quality control method for performing quality control on dynamic radiography in which a dynamic state of a subject is captured by irradiating the subject with radiation, the method comprising: determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic radiography, and generating information regarding the quality of the dynamic radiography using the determined frame image; outputting information relating to the quality of the dynamic imaging; Equipped with The frame image to be subjected to the quality control is This is a frame image between the middle and the end. , The information regarding the quality of the dynamic imaging includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks. [Effects of the Invention]

[0012] According to the present invention, quality control of dynamic radiography consisting of a plurality of frames can be appropriately performed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram illustrating an example of a radiation imaging system according to an embodiment of the present invention. [Figure 2] 2 is a transparent plan view showing the inside of an example of a quality control phantom used for quality control of the radiation imaging system of FIG. 1. FIG. [Figure 3] 2 is a plan view showing an example of a dynamic phantom for quality control used for quality control of the radiation imaging system of FIG. 1. FIG. [Figure 4] 2 is a block diagram showing a dynamic quality control device provided in the radiation imaging system of FIG. 1. FIG. [Figure 5] 5 is a flowchart showing the flow of dynamic quality control processing executed by the dynamic quality control device of FIG. 4. [Figure 6] 6 is a conceptual diagram showing an example of an operation performed by a dynamic quality control device in the dynamic quality control process of FIG. 5. FIG. [Figure 7] 7 is a conceptual diagram showing another example of the operation performed by the dynamic quality control device in the dynamic quality control process of FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments and illustrated examples.

[0015] <1. Radiography System> First, the schematic configuration of a radiation imaging system (hereinafter referred to as system 100) according to this embodiment will be described. FIG. 1 is a block diagram showing an example of system 100, FIG. 2 is a transparent plan view showing the interior of an example of a quality control phantom used for quality control of system 100, and FIG. 3 is a plan view showing an example of a quality control dynamic phantom used for quality control of system 100.

[0016] As shown in FIG. 1, the system 100 includes a radiation detector (hereinafter, detector 1) and a dynamic quality control device (hereinafter, control device 2). The system 100 according to this embodiment further includes a radiation generating device (hereinafter referred to as a generating device 3) and a console 4. The devices 1 to 4 are capable of communicating with each other via, for example, a communication network N (such as a local area network (LAN), a wide area network (WAN), or the Internet).

[0017] In addition, system 100 may be capable of communicating with a Hospital Information System (HIS), a Radiology Information System (RIS), a Picture Archiving and Communication System (PACS), a dynamic analysis device, etc., which are not shown.

[0018] [1-1. Radiation Generator] The generating device 3 includes a generator 31 , an irradiation instruction switch 32 , and a radiation source 33 . The generator 3 may be installed in the radiography room, or may be configured together with the console 4 and the like as a movable device called a medical cart.

[0019] When the irradiation instruction switch 32 is operated, the generator 31 applies a voltage to the radiation source 33 (tube) according to the preset imaging conditions (for example, conditions related to the subject S, such as the imaging region, imaging direction, and physique, and conditions related to the irradiation of radiation X, such as the tube voltage, tube current, irradiation time, and current-time product (mAs value)).

[0020] When a voltage is applied from the generator 31, the radiation source 33 generates radiation X (for example, X-rays) at a dose corresponding to the applied voltage. Furthermore, radiation source 33 can move in the X-axis direction (radiation irradiation direction, left-right direction in FIG. 1), the Y-axis direction perpendicular to the X-axis (direction perpendicular to the paper surface in FIG. 1), and the Z-axis direction perpendicular to the X-axis and Y-axis (up-down direction in FIG. 1), and can also rotate around rotation axes parallel to the Y-axis and Z-axis to change the orientation of the radiation irradiation port.

[0021] The generator 3 is also configured to generate radiation X in a manner that corresponds to the form of the radiation image to be generated (a still image, a dynamic image made up of a plurality of frame images). In the case of a still image, radiation X is irradiated only once per depression of the irradiation instruction switch 32. In the case of dynamic images, each time the irradiation instruction switch 32 is pressed, the irradiation of pulsed radiation X is repeated multiple times per predetermined time (for example, 15 times per second), or the irradiation of radiation X is continued for a predetermined time. That is, in the present invention, "sequential irradiation with radiation" includes continuous irradiation in which radiation is continuously irradiated, and pulse irradiation in which radiation is irradiated intermittently or not.

[0022] [1-2. Radiation detector] Although not shown in the figure, the detector 1 includes a sensor substrate on which radiation detection elements that generate an electric charge according to the dose when exposed to radiation X and switch elements that accumulate and release the electric charge are arranged two-dimensionally (in a matrix), a scanning circuit that switches each switch element on and off, a readout circuit (hereinafter referred to as ROIC) that reads out the amount of electric charge released from each pixel as a pixel value, a control unit that generates a radiographic image from the multiple pixel values ​​read out by the ROIC, and a communication unit that transmits data on the generated radiographic image and various signals to the outside and receives various information and signals.

[0023] The detector 1 stores and releases electric charges and reads out pixel values ​​in synchronization with the timing at which radiation X is irradiated from the generator 3, thereby generating a radiological image according to the dose of the irradiated radiation X. When a still image is to be generated, a radiographic image is generated only once per depression of the irradiation instruction switch 32. When a dynamic image is generated, frame images constituting the dynamic image are generated multiple times per predetermined time (for example, 15 times per second) for each depression of the irradiation instruction switch 32.

[0024] The detector 1 may be configured to store and transfer the generated dynamic image in the form of image data, or to display it in real time on a display device connected to the detector 1. An example of real-time display is fluoroscopy.

[0025] [1-3. Console] The console 4 sets various imaging conditions (tube voltage, tube current, irradiation time (mAs value), imaging region, imaging direction, etc.) for at least one of the detector 1 and the generator 3. The console 4 is composed of a PC, dedicated devices, etc. Furthermore, the console 4 sets the imaging conditions based on imaging order information acquired from other systems (such as an HIS or RIS) or on operations performed by a user (such as a technician).

[0026] [1-4. Dynamic quality control device] The management device 2 performs quality control regarding dynamic radiography. Here, "dynamic imaging" refers to imaging the dynamic state of the subject S by sequentially irradiating the subject S with radiation. Furthermore, "dynamic photography" includes video photography, but does not include taking still images while displaying a video. Furthermore, "dynamic images" include moving images, but do not include images obtained by capturing still images while displaying a moving image. Furthermore, the management device 2 targets for "quality control" at least a part of the series of operations (program execution) of the system 100 when performing dynamic imaging (for example, at least one of the operations of irradiating radiation X by the radiation generating device 3, generating dynamic images by the detector 1, transferring dynamic images between devices, analyzing by the dynamic analysis device, and saving dynamic images to a data storage device (cloud server, PACS, etc.)). In addition, "quality control" includes not only quality control through regular quality checks after product delivery, but also quality assurance at the time of product delivery.

[0027] The management device 2 is configured by a PC, a dedicated device, or the like. Although FIG. 1 illustrates the system 100 in which the management device 2 and the console 4 are provided separately, the management device 2 and the console 4 may be integrated. Furthermore, if the system 100 includes a dynamic analysis device, a PACS, or the like (not shown), the management device 2 may be integrated with these devices. The management device 2 will be described in detail later.

[0028] [1-5. Quality control phantom] In quality control using the management device 2, a quality control phantom (hereinafter referred to as phantom 5) may be used. That is, the system 100 may use the phantom 5 as the subject S. As shown in FIG. 2, the phantom 5 according to this embodiment has a rectangular substrate 51 (e.g., an acrylic plate) that is transparent to radiation, multiple types of evaluation members arranged on the substrate 51, and a sealing plate (e.g., an acrylic plate) (not shown) that is transparent to radiation and seals the evaluation members. The multiple types of evaluation members according to this embodiment are metal disks 52a to 52c, an edge pattern 53, a step wedge 54, and jitters 55a and 55b.

[0029] The metal disks 52a to 52c are made of circular metal plates. The metal constituting the metal disks 52a to 52c includes, for example, copper. The metal disks 52a to 52c are located at the three corners of the substrate 51, respectively.

[0030] The edge pattern 53 is made of a metal plate having sharp edges formed thereon. The metal forming the edge pattern 53 includes, for example, tungsten. The edge portion of the edge pattern 53 is slightly inclined with respect to one side of the substrate 51 .

[0031] The step wedge 54 has a plurality of (for example, four) rectangular metal plates 54a to 54d that differ from each other in thickness. The metal constituting each of the metal plates 54a to 54d includes, for example, copper. The metal plates 54a to 54d are arranged so that their thicknesses become thicker or thinner in stages.

[0032] The jitters 55a and 55b are made of rectangular metal (for example, copper) plates with straight edges. In addition, one of the long sides of the jitters 55a and 55b is aligned along one side of the substrate 51. The other long side is along another side of the substrate 51 that is perpendicular to the one side.

[0033] Although the phantom 5 having four types of evaluation members is exemplified here, the number of types of evaluation members that the phantom 5 has may be three or less, or may be five or more. Furthermore, although one phantom 5 is used for quality control here, a plurality of phantoms with different evaluation members disposed thereon may also be used for quality control.

[0034] Furthermore, a quality control dynamic phantom (hereinafter, dynamic phantom 6) may be used in quality control using the management device 2. That is, the system 100 may use the dynamic phantom 6 as the subject S. As shown in FIG. 3(a), the dynamic phantom 6 according to this embodiment has a power source 61 and a movable member 62 that performs a predetermined movement by the power source. The movable member 62 according to this embodiment has a disk 62a (for example, an acrylic plate) that has a property of transmitting radiation, a plurality of metal disks 62b, and a plurality of dials 62c.

[0035] The plurality of metal disks 62b are made of circular metal plates. The metal that constitutes the metal disk 62b includes, for example, copper. The metal disks 62b are arranged at equal intervals along the periphery of the disk 62a.

[0036] The plurality of dial plates 62c are made of metal plates shaped like numbers (for example, 1 to 6), and there are the same number of them as the metal disks 62b. The metal that constitutes the multiple dials 62c includes, for example, copper. The multiple dials 62c are arranged at equal intervals at positions closer to the center than the periphery of the disk 62a so as to correspond to the metal disks 62b.

[0037] Although the dynamic phantom 6 in which the movable member 62 rotates has been exemplified here, the movable member 62 of the dynamic phantom 6 may be one that reciprocates. The dial 62c may also be shaped like the alphabet.

[0038] [1-6. Outline of operation of the radiography system] The system 100 configured in this manner operates as follows. First, the generator 3 irradiates radiation X to the subject S (the area to be diagnosed of the examinee) located between the radiation source 33 of the generator 3 and the detector 1, which are arranged opposite each other with a gap between them. The detector 1 then generates a radiological image (still image, dynamic image) showing the area to be diagnosed, and transmits the image data to at least one of the management device 2 and the console 4. When performing quality control, the generator 3 irradiates radiation X onto phantoms 5 and 6 located between the radiation source 33 and the detector 1, and the detector 1 generates quality control images (still images, dynamic images: hereinafter referred to as QC images) containing the phantoms 5 and 6, and transmits the image data to the management device 2. When the management device 2 receives the image data of the QC image, it executes dynamic quality control processing (described in detail later) and outputs information relating to the quality of dynamic imaging (described in detail later).

[0039] <2. Details of dynamic quality control equipment> Next, the management device 2 included in the system 100 will be described in detail. FIG. 4 is a block diagram showing the management device 2, FIG. 5 is a flowchart showing the flow of the dynamic quality control process executed by the management device 2, and FIGS. 6 and 7 are conceptual diagrams showing the operations performed by the management device 2 in the dynamic quality control process.

[0040] [2-1. Configuration of dynamic quality control device] As shown in FIG. 4, the management device 2 includes a control unit 21, a storage unit 22, a communication unit 23, a display unit 24, and an operation unit 25. The units 21 to 25 are electrically connected by a bus or the like.

[0041] The control unit 21 is composed of a CPU (Central Processing Unit), RAM (Random Access Memory), and the like. The CPU of the control unit 21 reads out various programs stored in the memory unit 22, expands them in the RAM, executes various processes in accordance with the expanded programs, and centrally controls the operations of each unit of the management device 2.

[0042] The storage unit 22 is configured by a non-volatile memory, a hard disk, or the like. Furthermore, the storage unit 22 stores various programs (including a dynamic quality control program) executed by the control unit 21, parameters required for executing the programs, and the like. The storage unit 22 may be capable of storing image data of radiographic images acquired from other devices.

[0043] The communication unit 23 is composed of a communication module and the like. The communication unit 23 is configured to send and receive various signals and data to and from other devices (detector 1, console 4, etc.) connected by wire or wirelessly via a communication network N (LAN (Local Area Network), WAN (Wide Area Network), Internet, etc.).

[0044] The display unit 24 displays various screens used for diagnosis by the user. The display unit 24 is configured by, for example, an LCD (Liquid Crystal Display), an ELD (Electronic Luminescent Display), a CRT (Cathode Ray Tube), or the like. The display unit 24 displays a radiographic image or the like in accordance with the image signal received from the control unit 21 .

[0045] The operation unit 25 is an operation means configured to be operable by the user. The operation unit 25 includes a keyboard (cursor keys, numeric input keys, various function keys, etc.), a pointing device (mouse, etc.), a touch panel laminated on the surface of the display unit 24, etc. The operation unit 25 outputs a control signal to the control unit 21 in response to an operation performed by the user.

[0046] In addition, the management device 2 may not be equipped with a display unit 24 or an operation unit 25, and may be configured to receive control signals from an input device provided separately from the management device 2, for example, via a communication unit 23, or to output image signals to a display device (monitor) provided separately from the management device 2. Furthermore, if the other device (console 4, etc.) has a display unit and an operation unit, it may be configured to receive control signals from the operation unit of the other device and output image signals to the display unit of the other device (the display unit and operation unit may be shared with the other device).

[0047] [2-2. Operation of dynamic quality control device] The control unit 21 of the management device 2 configured as above executes a dynamic quality management process as shown in FIG. 5, for example, when a predetermined condition is met. The specified conditions include, for example, that the power of the management device 2 has been turned on, that image data has been acquired from another device, that a specified control signal has been received from another device, and that a specified operation has been performed on the operation unit 25 (for example, an operation to start dynamic quality control processing, an operation to select the quality check to be performed, etc.).

[0048] (Image data acquisition) In this dynamic quality control process, the control unit 21 first executes an acquisition process (step S1). In this acquisition process, the control unit 21 acquires image data according to the content of the quality check that is about to be performed. For example, the control unit 21 acquires image data of a QC image obtained by dynamic imaging of the phantom 5, a QC image obtained by dynamic imaging of a phantom having one evaluation component corresponding to the content of the quality check to be performed, a QC image obtained by dynamic imaging of the dynamic phantom 6, or a solid image obtained by dynamic imaging without the subject S present. In the acquisition process according to this embodiment, the control unit 21 receives image data via the communication unit 23.

[0049] In this acquisition process, the control unit 21 may read the image data from the storage unit 22 or from a medium. In addition, in this acquisition process, the control unit 21 may acquire image data of an image (medical image) obtained by dynamic imaging of an actual subject as the subject S. Furthermore, when the dynamic quality control process is started in response to the acquisition of image data, it is not necessary to execute the acquisition process during the dynamic quality control process.

[0050] (Generation of information on dynamic imaging quality) After acquiring the image data, the control unit 21 executes a generation process (step S2). In this generation process, the control unit 21 determines the frame image to be subject to quality control from among the multiple frame images that make up the dynamic image obtained by dynamic photography, and uses the determined frame image to generate information regarding the quality of the dynamic photography (hereinafter referred to as quality information). This "quality information" includes information indicating low contrast resolution of the dynamic image, and at least one of information indicating streaks and information indicating unevenness. The quality information according to this embodiment further includes at least one of information indicating the presence or absence of at least one of ROIC block unevenness and pixel value differences (hereinafter referred to as pixel value differences) at the boundaries of each sensor substrate, information indicating the presence or absence of motion artifacts, and information indicating the falling response of radiation X-rays. The "quality information" is output in the form of at least one of a numerical value indicating the quality, an image indicating the quality, and a quality judgment result (pass / fail, etc.).

[0051] In the generation process according to this embodiment, the control unit 21 first determines a frame image (hereinafter, referred to as a target frame image F) that is to be the target of quality control (used to generate quality information). Specifically, the control unit 21 first receives a selection of a predetermined frame image from the user via the operation unit 25. Then, the control unit 21 determines a target frame image F according to the selection received by the operation unit 25 from among the multiple frame images. For example, if the user selects at least one of the first and last frame images as the specified frame, the control unit 21 may be configured to determine at least one frame image excluding the selected frame image (e.g., the remaining frame images excluding at least one first frame image, the remaining frame images excluding at least one last frame image, the remaining frame images excluding at least one first and one last frame image, etc.) as the target frame image F.

[0052] Furthermore, if the user selects, for example, an intermediate frame image (for example, a frame image with a serial number closest to the median) as the predetermined frame image, the control unit 21 selects at least one frame image including the selected frame image (for example, several frame images before and after the intermediate frame image, or multiple frame images after the intermediate frame image (from the intermediate to the last frame image)). The target frame image F may be determined to be a frame image (including a frame image). Furthermore, if the user selects, for example, the first half of all the frame images as the predetermined frame image, the control unit 21 may determine the first 30% of all the frame images as the target frame image F.

[0053] In this way, by narrowing down the frame images used to generate the quality information, it is possible to shorten the time required for subsequent processing and reduce the amount of image data. Furthermore, since the radiation X generated by the generator 3 becomes stable from the latter half of the dynamic imaging, if a frame image between the middle and the end is used as the target frame image F, various calculations for generating quality information can be performed stably.

[0054] In this generation process, the control unit 21 may first determine, as the target frame image F, a frame image that satisfies a specific criterion from among a plurality of frame images. Specifically, the control unit 21 may be configured to determine the target frame image F from among the frame images captured at a predetermined dose or less (particularly, the one captured at the lowest dose). This is because the lower the dose, the more noticeable the contrast resolution, streaks, ROIC block irregularities, etc. Furthermore, if the specific criterion is, for example, "do not use the first frame image," then the first 10 to 30% of the image, excluding the first frame image, may be determined as the target frame image F. Furthermore, in this generation process, the control unit 21 may be configured to determine one target frame image F. Furthermore, in this generation process, the control unit 21 may be configured to omit accepting the user's selection of a predetermined frame image, if necessary.

[0055] In addition, the control unit 21 may be configured to automatically determine the target frame image F, or may be configured to receive information about the target frame image F from the user via the operation unit 25, and (manually) determine the frame image to be subject to quality control based on the information received by the operation unit 25. This "information regarding the target frame image F" includes at least one of the frame number of the target frame image F, quality check items (low contrast resolution, etc.), radiation dose at the time of imaging, and whether or not a phantom 5 or a dynamic phantom 6 was used. In this case, the operation unit 25 serves as a reception unit.

[0056] Furthermore, in the generation process according to this embodiment, the control unit 21 sets the partial region R in parallel with, before, or after determining the frame image. For example, if the image data acquired in the above acquisition process is a QC image obtained by dynamic imaging of the phantom 5, the control unit 21 sets the area in the QC image that shows the evaluation component corresponding to the content of the quality check to be performed as the partial area R. Specifically, for example, when checking low contrast resolution, the area in the QC image in which the metal disks 52a to 52c are captured is set as the partial area R.

[0057] Furthermore, if the image data acquired in the acquisition process is a QC image obtained by dynamic imaging of the dynamic phantom 6, the control unit 21 sets the region in the QC image in which the movable member 62 is captured as the partial region R.

[0058] The control unit 21 may be configured to set the partial area R automatically, or may be configured to set it (manually) in response to an operation performed on the operation unit 25 by the user. Furthermore, when a medical image is acquired in the acquisition process, the control unit 21 may, for example, A region of interest (ROI: Region of Interest, a region where a certain level of image quality is required) or an element that affects image quality (ROIC block, etc.) may be set in the partial region R. Furthermore, if the above acquisition process acquires a QC image in which only one evaluation component is captured across the entire frame image, or if the acquisition process acquires a solid image and the control unit 21 has sufficient processing capacity (it is acceptable to perform calculations on all pixels of each frame), there is no need to set this partial area R.

[0059] In the dynamic quality control process according to this embodiment, the control unit 21 sets a partial region R, and then generates quality information using the determined single target frame image F (with noise included in the pixel values).

[0060] (low contrast resolution) For example, when generating information indicating low contrast resolution as quality information (acquiring a QC image using an acquisition means, and setting the area in which the metal discs 52a to 52c appear in the target frame image F of the acquired QC image as the partial area R), the control unit 21 calculates the contrast ratio of the partial area R set in one target frame image F, as shown in Figure 6, for example. Furthermore, if necessary, an image according to the calculated ratio is generated, and it is determined whether the calculated ratio indicates that the image has sufficient low contrast resolution. At this time, it is possible to average the contrast ratios of the frame images. In this case, the control unit 21 generates the quality information using at least two frame images.

[0061] (with or without streaks) When generating the presence or absence of streaks in a single frame image as quality information, the control unit 21 acquires a pixel value profile of the single frame image in a direction perpendicular to the extension direction of the streaks, and determines whether or not there is a fluctuation in the pixel values ​​using techniques such as frequency analysis, amplitude analysis, and SD analysis. At this time, it is possible to average the analysis results of the pixel value profiles of the frame images. In this case, the control unit 21 generates quality information using at least two frame images. The same method as that for checking the presence or absence of streaks as described above can also be used to detect the presence or absence of electromagnetic noise, disturbance streaks, etc.

[0062] (ROIC block unevenness / pixel price difference) The detector 1 may have multiple ROICs on one sensor substrate, with each ROIC reading out a signal value from a different column. When using such a detector 1, differences in pixel values ​​between rows (ROIC block unevenness) may occur due to differences in the characteristics of each ROIC. Furthermore, the detector 1 may include a plurality of sensor substrates. In this case, since each sensor substrate has its own ROIC, differences in pixel values ​​(pixel value differences) may occur at the boundaries of each sensor substrate. Therefore, information indicating the presence or absence of at least one of ROIC block unevenness and pixel value difference is generated as quality information (when an unexposed image (especially a frame image generated some time after the start of acquisition of a dark image for offset correction: a frame image in which ROIC block unevenness is significant) is acquired during the acquisition process), the control unit 21 acquires a pixel value profile in the target frame image F in a direction perpendicular to the extension direction of the signal line of the sensor board connected to the ROIC. Then, ROIC block irregularities are detected from the acquired pixel value profile. The pixel value difference can also be detected in the same manner as the ROIC block unevenness.

[0063] (Presence or absence of motion artifacts) If a dynamic image is affected by motion artifacts, the shape of the subject S shown in the frame image will be distorted (for example, if the dynamic phantom 6 is the subject S, the image of the circular movable member 62 will appear elliptical). Therefore, when generating information indicating the presence or absence of motion artifacts as quality information, the control unit 21 measures values ​​indicating the shape of the movable member 62 of the dynamic phantom 6 (for example, the vertical diameter and horizontal diameter, the ratio between these, etc.). Furthermore, if necessary, an image corresponding to the measured values ​​is generated, and it is determined whether or not the measured values ​​indicate deformation of the image.

[0064] (with or without lugs) When generating information indicating the presence or absence of lag (afterimage) as quality information, the control unit 21 identifies an area in one frame image that is located on the same coordinates as the area in which the movable member of the dynamic phantom 6 was captured in the previous frame image, based on, for example, how the movable member 62 is captured in one frame image, the movement speed of the dynamic phantom 6, the frame rate, etc. Then, it calculates the ratio between the pixel values ​​of the pixels that make up the identified area and the pixel values ​​of the pixels surrounding the identified area. Furthermore, if necessary, an image corresponding to the calculated ratio is generated, and it is determined whether or not the calculated ratio indicates the presence of an afterimage.

[0065] (Falling response of radiation) If the fall of the radiation X is slow (the wave tail of the radiation X is large), density unevenness appears in the pixel value profile in the signal line direction of the first frame image. Therefore, when generating information indicating the fall response of radiation X as quality information (when the first frame image is acquired in the acquisition process), the control unit 21 acquires a pixel value profile of the target frame image F. Then, it is determined whether the acquired pixel value profile is similar to the pixel value profile of the last frame image.

[0066] (Linearity of pixel values) For example, when generating quality information indicating the linearity of pixel values ​​read by detector 1 (acquiring a QC image in the acquisition process and setting the area in the acquired QC image where the step wedge 54 appears as partial area R), control unit 21 calculates average information (average value) of pixel values ​​obtained from partial area R in one of at least two target frame images F, and pixel values ​​obtained from a corresponding area located on the same coordinates as partial area R in the remaining target frame image F of at least two target frame images F, as shown in Fig. 7(a), for example. This reduces noise contained in the pixel values ​​in the area where the step wedge 54 appears. Then, based on the calculated average information, the control unit 21 calculates a value indicating the linearity between the dose of radiation (transmission dose) that has passed through each of the metal plates 54a to 54d of the step wedge 54 and the pixel values ​​of the area in which each of the metal plates 54a to 54d is imaged. Furthermore, if necessary, an image corresponding to the calculated value is generated, and it is determined whether the calculated value exhibits sufficient linearity.

[0067] (Uniformity of pixel values) When generating information indicating the uniformity of pixel values ​​read by the detector 1 as quality information (acquiring a QC image in the acquisition process and setting the area in the acquired QC image where the edge pattern 53 appears as the partial area R), the control unit 21 may, for example, as shown in FIG. 7(b), set the pixel values ​​obtained from the partial area R in one of the at least two target frame images F and the pixel values ​​obtained from the partial area R in the remaining target frame image F of the at least two target frame images F. Average information (average value) of pixel values ​​obtained from a corresponding region located on the same coordinates as the partial region R in the image F is calculated. This reduces noise contained in the pixel values ​​of the region where the edge pattern 53 appears. Then, based on the calculated average information, the control unit 21 calculates a value indicating the variation in pixel values ​​of the pixels that make up the area where the edge pattern 53 appears. Furthermore, if necessary, an image corresponding to the calculated value is generated, and it is determined whether or not the calculated value indicates sufficient uniformity.

[0068] If quality information indicating that the required quality is not met is generated in the generation process described above, the control unit 21 may be configured to generate at least one of a confirmation item for the quality information indicating that the required quality is not met and a reason why the quality information indicating that the required quality is not met has been generated. The check items may be generated, for example, by referring to a table stored in advance in the memory unit 22 that shows the relationship between quality information indicating that the required quality is not met and the check items (possible causes), or by inputting the quality information indicating that the required quality is not met that has been generated this time into a trained model that has been machine-learned with the quality information as input and the check items as output.

[0069] The control unit 21 according to this embodiment serves as a generating means by executing the generating process described above. The step of the control unit 21 executing the generation process corresponds to the step of generating information about the quality of dynamic imaging in the dynamic quality control method.

[0070] [Output of information on the quality of dynamic photography] After generating the quality information, the control unit 21 executes an output process (step S3). In this output process, the control unit 21 outputs the generated quality information. In the output process according to this embodiment, the control unit 21 causes the display unit 24 to display quality information (numerical values, images, judgment results, etc.). In this output process, the control unit 21 may transmit the quality information to another device (for example, the console 4, a mobile terminal, a printer, etc.) (to display or print on the other device). Furthermore, if the management device 2 is provided with a means for writing to a recording medium, the control unit 21 may write the quality information to the recording medium in this output process.

[0071] In this output process, the control unit 21 may output the quality information generated in the previous or previous generation process. In this case, the control unit 21 may be configured to output (for example, display in the form of a graph) the latest quality information and the past quality information together. In this way, it is possible to easily check whether any changes have occurred in the state of the system 100 between a quality check performed at a certain timing and a quality check performed at a later timing. In addition, in this output process, the control unit 21 may compare past quality information with the latest quality information, and output an alert if it determines that the quality has deteriorated by more than a predetermined amount.

[0072] Furthermore, if the above generation process generates quality information indicating that the required quality is not met, and at least one of a confirmation item for the quality information indicating that the required quality is not met and a reason why the quality information indicating that the required quality is not met is generated is generated, the control unit 21 may be configured to output at least one of the confirmation item and the reason in this output process.

[0073] Furthermore, if all of the quality information or a specified portion of the quality information generated in the above generation process indicates that the required quality is met, the control unit 21 may be configured to output in this output process that dynamic photography is possible. This prevents the user from taking dynamic images when there is a problem with at least a part of the system 100.

[0074] The control unit 21 according to this embodiment serves as an output unit by executing the output process described above. Furthermore, the step of the control unit 21 executing the output process corresponds to the step of outputting information about the quality of dynamic imaging in the dynamic quality control method.

[0075] <3. Effects> As explained above, the management device 2 according to this embodiment or the system 100 including this management device 2 performs quality control for dynamic imaging, which captures the dynamic state of a subject S by sequentially irradiating the subject S with radiation, and includes a control unit 21 (generation means, output means) that determines a frame image to be subject to quality control from a plurality of frame images that constitute a dynamic image obtained by dynamic imaging, generates quality information using the determined frame image, and outputs the quality information. Therefore, the management device 2 or the system 100 can appropriately manage the quality of dynamic photography consisting of a plurality of frame images.

[0076] <4.Other> It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention.

[0077] For example, the management device 2 or system 100 in the above embodiment only performs quality control for dynamic photography, but the management device 2 or system 100 may also perform quality control for both still image photography and dynamic photography. Furthermore, the management device 2 in the above embodiment is configured to execute the generation process and the output process, but if the system 100 is equipped with a dynamic analysis device, the generation process may be executed by the dynamic analysis device, and the management device 2 may execute the output process based on the analysis results.

[0078] Furthermore, 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 this example. Portable recording media such as CD-ROMs can also be used as other computer-readable media. Furthermore, carrier waves can also be used as a medium for providing data for the program according to the present invention via a communication line. [Explanation of symbols]

[0079] 100 Radiography System 1. Radiation detector 2 Dynamic quality control device 21 Control section 22 Memory section 23 Communications Department 24 Display 25 Control section 3. Radiation Generator 31 Generator 32 Irradiation instruction switch 33 Radiation source 4 Console 5. Phantom 51 PCB 52a~52c Metal disc 53 Edge Pattern 54 Step Wedge 54a~54d Metal plate 55a, 55b Jitter 6 Dynamic Phantom 61 Power 62 Movable parts 62a Disk 62b Metal disc 62c dial F Target frame image N Communication Network R Partial area S Subject X radiation

Claims

1. A dynamic quality control device for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: a generating means for determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; an output means for outputting information relating to the quality of the dynamic radiography; Equipped with The frame images to be subjected to the quality control are frame images between the middle and the last frame images, The dynamic image quality control device is characterized in that the information regarding the quality of the dynamic image capture includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks.

2. A dynamic quality control device for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: a generating means for determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; an output means for outputting information relating to the quality of the dynamic radiography; Equipped with A dynamic quality control device characterized in that the frame images to be subject to the quality control are frame images between the middle and the last, and include those taken at a predetermined dose or less.

3. 2. The dynamic quality control device according to claim 1, wherein the information relating to the quality of the dynamic image capture includes information indicating unevenness in the dynamic image.

4. 4. The dynamic quality control device according to claim 1, wherein the generating means determines, from among the plurality of frame images, a frame image that satisfies a specific standard as a frame image to be subject to quality control.

5. 5. The dynamic quality control device according to claim 4, wherein the generating means determines frame images to be subject to quality control from frame images captured at a predetermined dose or less.

6. The dynamic quality management device described in claim 1 or 2, characterized in that when the generation means generates quality information indicating that the predetermined required quality is not met, it further generates at least one of a confirmation item for the quality information indicating that the predetermined required quality is not met and a reason why the quality information indicating that the predetermined required quality is not met was generated.

7. 7. The dynamic quality control device according to claim 1, wherein the generating means determines one frame image to be the object of quality control.

8. a reception unit that receives information about a frame image to be subject to quality control from a user; the generating means determines frame images to be subject to quality control based on the information received by the receiving unit; The dynamic quality control device according to any one of claims 1 and 3 to 7, characterized in that:

9. A dynamic quality control program for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: On the computer, a process of determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; a process of outputting information relating to the quality of the dynamic imaging; Execute The frame images to be subjected to the quality control are frame images between the middle and the last frame images, A dynamic image quality control program, wherein the information regarding the quality of the dynamic image capture includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks.

10. A dynamic quality control program for performing quality control regarding dynamic radiography for capturing dynamic images of a subject by irradiating the subject with radiation, comprising: On the computer, a process of determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic imaging, and generating information on the quality of the dynamic imaging using the determined frame image; a process of outputting information relating to the quality of the dynamic imaging; Execute A dynamic quality control program characterized in that the frame images to be quality controlled are frame images between the middle and the last, and include those taken at a predetermined dose or less.

11. 10. The dynamic image quality control program according to claim 9, wherein the information relating to the quality of the dynamic image capture includes information indicating unevenness in the dynamic image.

12. The dynamic quality control program of claim 9 or claim 11, characterized in that the computer is caused to execute a process of determining, from among the plurality of frame images, frame images that meet specific criteria as frame images to be subject to quality control.

13. The dynamic quality control program according to claim 12, characterized in that the computer is caused to execute a process of determining frame images to be subject to quality control from among frame images taken at a predetermined dose or less.

14. The dynamic quality control program described in claim 9 or 10, characterized in that when the computer generates quality information indicating that the predetermined required quality is not met, it executes a process to further generate at least one of a confirmation item for the quality information indicating that the predetermined required quality is not met and a reason why the quality information indicating that the predetermined required quality is not met was generated.

15. 15. The dynamic quality control program according to claim 9, further comprising causing the computer to execute a process of determining one frame image to be the object of quality control.

16. 1. A dynamic quality control method for performing quality control on dynamic radiography in which a dynamic state of a subject is captured by irradiating the subject with radiation, the method comprising: determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic radiography, and generating information regarding the quality of the dynamic radiography using the determined frame image; outputting information about the quality of the dynamic imaging; Equipped with The frame images to be subjected to the quality control are frame images between the middle and the last frame images, A dynamic quality control method, characterized in that the information regarding the quality of the dynamic image capture includes at least one of information indicating low contrast resolution of the dynamic image and information indicating streaks.

17. 1. A dynamic quality control method for performing quality control on dynamic radiography in which a dynamic state of a subject is captured by irradiating the subject with radiation, the method comprising: determining a frame image to be subjected to quality control from among a plurality of frame images constituting the dynamic image obtained by the dynamic radiography, and generating information regarding the quality of the dynamic radiography using the determined frame image; outputting information about the quality of the dynamic imaging; Equipped with A dynamic quality control method characterized in that the frame images to be subject to the quality control are frame images between the middle and the last, and include those taken at a predetermined dose or less.

18. 17. The dynamic quality control method according to claim 16, wherein the information relating to the quality of the dynamic image capture includes information indicating unevenness in the dynamic image.

19. 19. The dynamic quality control method according to claim 16 or 18, wherein frame images that satisfy a specific standard are determined from the plurality of frame images as frame images to be subject to quality control.

20. 20. The dynamic quality control method according to claim 19, wherein frame images to be subject to quality control are determined from frame images captured at a predetermined dose or less.

21. A dynamic quality control method as described in claim 16 or 17, characterized in that if, in the step of generating information regarding the quality of the dynamic photography, quality information indicating that the predetermined required quality is not met is generated, the method further comprises a step of generating at least one of a confirmation item regarding the quality information indicating that the predetermined required quality is not met and a reason why the quality information indicating that the predetermined required quality is not met was generated.

22. 22. The dynamic quality control method according to claim 16, further comprising determining one frame image to be the object of quality control.

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