JP2018202043A - Radiographic apparatus, radiographic system, radiographic method, and program - Google Patents

Abstract

To reduce the effect of an artifact that may occur due to the last imaging mode before switching.SOLUTION: Provided is a radiographic apparatus operable in a plurality of imaging modes and including a radiation detector which captures a radiographic image based on electric charge accumulated by irradiation in an imaging mode selected by switching from any one imaging mode among the plurality of imaging modes. The radiographic apparatus includes: an image acquisition unit for acquiring an offset image corresponding to a combination of the last imaging mode before the switching and a wait time between the end of the last imaging mode and the beginning of an imaging in the imaging mode selected by switching; and an offset correction unit for correcting the offset components of the radiographic image using the acquired offset image.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radiation imaging apparatus, a radiation imaging system, a radiation imaging method, and a program.

  2. Description of the Related Art A radiation imaging apparatus that obtains a radiation image by irradiating a subject with radiation from a radiation generation apparatus and performing image processing on image data obtained by digitizing a radiation intensity distribution transmitted through the subject has been commercialized.

  In the radiation imaging apparatus, a certain amount of signal charge (dark charge) is generated even when radiation is not irradiated. In order to prevent deterioration in image quality due to dark charges superimposed on signal charges due to radiation irradiation, an image in which radiation is irradiated (hereinafter referred to as a radiation image) and an image in which radiation is not irradiated (hereinafter referred to as an offset image) The component of the difference (hereinafter referred to as offset component) is corrected. Since the offset image can change according to the use environment of the radiation imaging apparatus, the energization time, the change of the imaging mode, etc., it is necessary to hold the offset image corresponding to the use environment etc. while updating it as needed. In radiation imaging devices that support various imaging modes such as fluoroscopy and still image imaging, the offset component can be corrected according to differences in image size, frame rate, amplifier gain, etc. by changing (switching) the imaging mode. I need it.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a configuration in which offset data of an imaging mode is controlled stepwise during a transition period from the imaging mode to the fluoroscopic mode when a radiographic image is obtained by switching from the imaging mode to the fluoroscopic mode.

JP 2004-194702 A

  However, in the configuration of Patent Document 1, an offset component corresponding to the passage of time after the change of the imaging mode can be corrected, but artifacts generated due to the influence of the imaging mode before switching may remain.

  In view of the above-described problems, the present invention can reduce the influence of artifacts that may occur due to the influence of the imaging mode before switching by performing offset correction using an offset image that takes into account the imaging mode before switching. The purpose is to provide a radiological imaging technology.

A radiation imaging apparatus according to an aspect of the present invention is operable in a plurality of imaging modes, and switches a radiographic image based on charges accumulated by irradiation of radiation from any one of the plurality of imaging modes. A radiation imaging apparatus having radiation detection means for acquiring based on the obtained imaging mode,
Image acquisition means for acquiring an offset image corresponding to a combination of the imaging mode before switching and the standby time from the end of the imaging mode to the start of imaging in the switched imaging mode;
Offset correction means for correcting an offset component of the radiographic image using the acquired offset image.

  According to the present invention, it is possible to reduce the influence of artifacts that may occur due to the influence of the imaging mode before switching.

The figure which shows the structural example of the radiation imaging system in embodiment. The figure which shows the structural example of the radiation detection part in a radiation imaging device. The figure which illustrates roughly offset correction in a radiographic imaging apparatus. The figure which shows the example of a table of the use condition of a radiographic imaging apparatus. FIG. 5 is a diagram for exemplarily explaining an imaging operation in the embodiment. FIG. 5 is a diagram for exemplarily explaining an imaging operation in the embodiment. The figure which illustrates the structure of an offset table.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the components described in this embodiment are merely examples, and the technical scope of the present invention is not limited by the following embodiments.

(Configuration example of radiation imaging system)
FIG. 1 is a diagram illustrating a configuration example of a radiation imaging system according to an embodiment. The radiation imaging system includes a radiation imaging apparatus 100 having a radiation detection unit 200, a radiation generation apparatus 300 that controls a radiation source 301 that emits radiation, and a control apparatus 400 that controls the radiation imaging apparatus 100 and the radiation generation apparatus 300. Have.

  The control device 400 is connected to a network 500 such as a LAN (Local Area Network). The network 500 is connected to a radiation information system RIS (Radiology Information System) or a hospital information system HIS (Hospital Information System) (HIS / RIS 501). The control device 400 and the HIS / RIS 501 can communicate with each other, and can exchange an imaging order of radiographic images, imaging information including patient information, and captured image data, for example.

  The radiation imaging apparatus 100 includes a radiation detection unit 200 that detects radiation and generates image data, a control unit 101 that controls imaging and communication operations performed by the radiation imaging apparatus 100, and a power supply unit 116. Here, the control unit 101 has the following functional configuration. The drive control unit 102 controls driving of the radiation detection unit 200 and acquisition of a radiation image and an offset image. The image processing unit 107 performs image processing on the image acquired from the radiation detection unit 200. The offset image collection control unit 109 controls timing for acquiring an offset image. For example, the offset image collection control unit 109 (collection control unit) sets the acquisition timing of the offset image for correcting the offset component of the radiation image based on the determination result of the use state of the radiation imaging apparatus 100 by the use state monitoring unit 114. Is possible. The storage unit 110 stores the acquired image data (radiation image, offset image).

  The communication control unit 113 controls communication with the control device 400. The usage state monitoring unit 114 monitors the usage state of the radiation imaging system (radiation imaging apparatus). The internal clock 115 (timer) acquires the imaging time, the elapsed time from the time when the imaging mode is switched, time information for periodically acquiring (collecting) the offset image, and the like.

  For example, the control unit 101 can read a program or the like stored in the storage unit, and control the entire radiation imaging apparatus based on the program. Alternatively, device control may be performed by a control signal generation circuit such as an ASIC, or control of the entire device may be realized by both a program and a control circuit.

  The control device 400 has the following functional configuration. The imaging control unit 402 controls the image acquisition timing and imaging conditions of the radiation imaging apparatus 100. The generation control unit 403 controls the irradiation timing and irradiation conditions of the radiation generation apparatus 300. The communication control unit 401 controls communication with the radiation imaging apparatus 100, communication with the radiation generation apparatus 300, and communication with the network 500. The radiation imaging application 404 is an application that controls processing such as collection and display of captured images from the radiation imaging apparatus 100, reception of imaging orders, and registration of imaging information. The display unit 406 displays captured images and imaging information. The operation UI 407 functions as a user interface for operating the radiation imaging system.

  Here, between the control device 400 and the radiation imaging device 100, and between the control device 400 and the radiation generation device 300, wired communication by cable connection using standards such as RS232C, USB, Ethernet (registered trademark), Information communication can be performed using either a dedicated signal line, wireless communication, or a combination thereof. For example, the control device 400 and the radiation imaging device 100 exchange control signals such as image data, image acquisition condition setting and device state acquisition, and synchronization signals such as notification of image acquisition timing and radiation irradiation possible timing. Is possible. Further, between the control device 400 and the radiation generation device 300, for example, exchange of synchronization signals such as setting of radiation irradiation conditions, acquisition of device state, control communication of actual irradiation information, and notification of radiation irradiation timing is performed. It is possible.

(Configuration example of radiation detection unit 200)
FIG. 2 is a diagram illustrating a configuration example of the radiation detection unit 200. The radiation detection unit 200 can operate in a plurality of imaging modes with different frame rates, and a radiation image based on the charge accumulated by radiation irradiation is switched from any one of the plurality of imaging modes. It is possible to acquire based on the imaging mode. The radiation detection unit 200 includes a sensor array 204 including a plurality of pixels arranged in a two-dimensional array so as to form a plurality of rows and a plurality of columns. Each pixel 207 on the sensor array includes, for example, a switch element 208 such as a TFT and a photoelectric conversion element 209, and a phosphor is provided on each pixel 207, for example.

  In this case, the radiation incident on the radiation detection unit 200 is converted into visible light by the phosphor, and the converted visible light is incident on the photoelectric conversion element 209 of each pixel, and each photoelectric conversion element 209 responds to visible light. Charge is generated. In the present embodiment, the phosphor and the photoelectric conversion element described above constitute a conversion element that converts incident radiation into electric charges. However, for example, a configuration in which a so-called direct conversion type conversion element that directly converts incident radiation into electric charges without providing a phosphor may be used. A radiographic image can be acquired by executing charge accumulation and charge readout by switching on and off the switch element 208 (TFT).

  The pixels on a certain row on the two-dimensional sensor array of the radiation detection unit 200 apply the ON voltage of the switch element 208 (TFT) to the drive line 211 by the drive circuit 201 (drive unit), thereby The TFT of the pixel is turned on, and the charge is held in the sample hold circuit 202 (holding unit) through each signal line 210. Thereafter, the held charge of the pixel output is sequentially read out through the multiplexer 203 (output control unit), amplified by the amplifier 205 (amplification unit), and then converted into a digital value by the A / D converter 206 (conversion unit). Converted to image data.

  Further, in the row where the readout of the charge is completed, the drive circuit 201 applies the OFF voltage of the TFT to the drive line 211, so that each pixel on the row returns to the accumulation of the charge. In this way, the drive circuit 201 sequentially scans the rows on the sensor array to perform scanning, and finally, the charges of all pixel outputs are converted into digital values. Thereby, radiation image data can be read. The drive control unit 102 controls the radiation detection unit 200 such as driving and reading operations. The image data converted into the digital value is stored in the storage unit 110 in FIG.

  The drive control unit 102 is configured to be able to switch a plurality of controls. That is, the drive control unit 102 prepares an imaging preparation drive control 103 that prepares a radiation imageable state, a standby drive control 104 that controls a standby drive state, a radiation image acquisition control 105 that acquires a radiation image, and an offset image. The offset image acquisition control 106 to be acquired can be switched and controlled. By executing the offset image acquisition control 106, the drive control unit 102 performs the imaging mode before switching in the radiation detection unit 200 (pre-driving mode) and the imaging mode from the end of the imaging mode to the start of imaging in the switched imaging mode. It functions as an image acquisition unit that acquires an offset image corresponding to a combination with time (standby time).

  The imaging preparation drive control 103 is a control that periodically reads out charges while resetting the dark charges accumulated in each pixel while applying the same voltage to the radiation detection unit 200 as during imaging. The charges read at this time are not handled as image data and do not have to be stored in the storage unit 110.

  The radiation image acquisition control 105 is a control for irradiating radiation during accumulation of each pixel while performing the same drive as the imaging preparation drive control 103. At this time, by switching on and off the switch element 208 (TFT) in the radiation detection unit 200, charge accumulation and charge read are executed, and the read charge is amplified by the amplifier 205 (amplification unit). The A / D converter 206 (converter) converts the image data into digital image data and outputs the image data from the radiation detector 200. The drive control unit 102 stores the image data output from the radiation detection unit 200 in the storage unit 110 as the radiation image 111 by executing the radiation image acquisition control 105. The drive control unit 102 can perform imaging as a moving image by continuously executing the radiation image acquisition control 105. Further, the drive control unit 102 can perform imaging as a still image by executing the radiation image acquisition control 105 once (non-continuously).

  Similarly to the imaging preparation drive control 103, the drive control unit 102 executes the control at a predetermined timing for the offset image acquisition control 106, so that the image data output from the radiation detection unit 200 without being irradiated with radiation is obtained. The offset image 112 is stored in the storage unit 110. The storage unit 110 can store a plurality of offset images acquired by executing the offset image acquisition control 106 by the drive control unit 102.

(Outline explanation of offset correction)
FIG. 3 is a diagram schematically illustrating offset correction. The radiation detection unit 200 of the radiation imaging apparatus 100 can operate in a plurality of imaging modes, and a radiographic image based on charges accumulated by radiation irradiation can be switched from any one of the plurality of imaging modes. Can be acquired based on the imaging mode. The drive control unit 102 stores, in the storage unit 110, an offset image acquired in advance when radiation is not irradiated by executing the offset image acquisition control 106. The drive control unit 102 acquires an offset image corresponding to a combination of the imaging mode before switching and the standby time from the end of the imaging mode to the start of imaging in the switched imaging mode from the storage unit 110.

  The offset correction unit 108 of the image processing unit 107 corrects the offset component of the radiation image using the offset image acquired by the drive control unit 102. The offset correction unit 108 performs offset correction by taking a difference between the radiation image 111 acquired from the radiation detection unit 200 at the time of imaging and the offset image 112 acquired at the time of non-imaging (at the time of non-irradiation of radiation) in advance. Then, after obtaining the corrected image 117 and executing the offset correction process, the offset correction unit 108 transfers the corrected image 117 to the control device 400 through the communication control unit 113.

  Although the offset correction processing has been described here, the functional configuration of the image processing unit 107 includes correction processing such as correction of defective pixels and gain correction for correcting gain variations of amplifiers in the radiation detection unit, for example. An executable processing unit may be included.

  Further, these correction processes are not limited to execution by the radiation imaging apparatus 100. For example, the acquired radiation image 111 and offset image 112 are transferred to the control apparatus 400 without being corrected by the radiation imaging apparatus 100, and controlled. Correction processing may be performed in the apparatus 400. Further, as the offset image used for the offset correction process, for example, an offset image obtained by using a plurality of offset images and performing a noise component reduction process by averaging or the like may be used as the offset image.

  The control unit 101 of the radiation imaging apparatus 100 includes a usage state monitoring unit 114 that monitors the usage state of the radiation imaging system (radiation imaging apparatus). As a use state of the radiation imaging system, for example, a use state as shown in FIG. 4 exists. FIG. 4 is a diagram illustrating the usage state of the radiation imaging apparatus, and the usage state monitoring unit 114 performs radiation imaging from information indicating the communication state between the radiation imaging apparatus 100 and the control device 400 or the state of the radiation imaging apparatus. The use state of the system (radiation imaging apparatus) is determined. The usage state monitoring unit 114 determines the usage state of the radiation imaging apparatus based on information indicating the state of the radiation imaging apparatus, and the drive control unit 102 and the offset image collection control unit 109 (collection control unit) monitor the usage state. Based on the determination result of the unit 114, the offset image is acquired (collected) at a predetermined timing.

  Depending on the usage state of the radiation imaging apparatus determined by the usage state monitoring unit 114, the driving control method of the radiation detection unit 200 and the offset image acquisition (collection) method during non-imaging are switched. Hereinafter, the operation of the radiation imaging apparatus 100 during imaging will be described with reference to FIG. Here, the operation of the radiation imaging apparatus 100 will be described mainly focusing on the points related to the acquisition (collection) of offset images.

(Not in use)
The usage state monitoring unit 114 determines the usage state of the radiation imaging system. For example, when only the radiation imaging apparatus 100 is activated and the control apparatus 400 is in a power-off state, the use state monitoring unit 114 determines that the system is not in use (use state A). In this case, the usage state monitoring unit 114 sets system state information so that the offset image acquisition control unit 109 and the drive control unit 102 do not acquire (collect) the offset image. In the usage state A, for example, when the radiation imaging apparatus 100 is not used at night, the power is turned on to keep warm air on the radiation imaging apparatus 100 side, while the power supply on the control apparatus 400 side is unused and is turned off. is assumed. In the system non-use state (use state A), offset images are not collected (OFF).

(Temporary suspension)
As a use state of the radiation imaging system, for example, the radiation imaging apparatus 100 and the control apparatus 400 are both activated, but the operator (operator) is not operating each apparatus (for example, in a waiting time between examinations). In a corresponding state, a state where the operator is temporarily away, or the like), the use state monitoring unit 114 determines a temporary use stop state (use state B). In this case, the use state monitoring unit 114 sets system state information in the offset image collection control unit 109 so as to periodically acquire (collect) an offset image as a temporary use stop state of the system.

  The internal clock 115 (timing unit) acquires time information for periodically acquiring (collecting) the offset image, and in the usage state B, when the timing for acquiring the offset image periodically is reached. Under the control of the offset image collection control unit 109, the drive control unit 102 releases the standby drive control 104 and starts the imaging preparation drive control 103. As described above, since the charge of the sensor array 204 is not stable immediately after switching from the standby drive control 104 to the imaging preparation drive control 103, the drive control unit 102 performs the offset image acquisition control 106 after waiting for a certain period of time. Get an offset image. In the temporary use stop state (use state B), the collection of the offset image is in the automatic collection mode (automatic collection of the offset image).

  The drive control unit 102 returns to the standby drive control 104 again after the offset image acquisition control 106 completes the acquisition of the offset image. In the use state B, when the offset image acquisition timing is not reached, the drive control unit 102 performs standby drive control 104. In the usage state B, the standby drive control 104 suppresses the TFT characteristic deterioration and periodically acquires (collects) the offset image, thereby reducing the standby time when the use is resumed.

(In use)
The use state monitoring unit 114 determines that the use state (use state C) is in use when the radiation imaging system is in use, for example, during inspection or preparation for inspection. In this case, the use state monitoring unit 114 sets the system state information in the offset image collection control unit 109 so as to periodically acquire (collect) the offset image, and the drive control unit 102 sets the radiation detection unit 200. Imaging preparation drive control 103 is performed.

  In the usage state C, when it is time to acquire the offset image periodically, the drive control unit 102 performs the offset image acquisition control 106 under the control of the offset image acquisition control unit 109 to acquire the offset image. In the in-use state (use state C), the offset image is collected in the automatic acquisition mode (offset image automatic acquisition). If the timing for obtaining the offset image is not reached, the drive control unit 102 continues the imaging preparation drive control 103 as it is.

  The use state D is a state in which the system state is the same as the use state C, but for example, an operation of manually acquiring an offset image by instructing from the operation UI 407 through the control device 400 from the outside. In the in-use state (use state D), the collection of the offset image is in the manual collection mode based on the input from the operation UI 407 (manual collection of the offset image).

  In the usage state D, the drive control unit 102 acquires an offset image corresponding to the combination of the standby time based on the input from the operation UI 407 and the imaging mode before switching based on the determination result of the usage state monitoring unit 114. . In the offset image manual acquisition mode, the drive control unit 102 performs the offset image acquisition control 106 and combines the imaging mode before switching (previous drive mode) and the time based on the input from the operation UI 407 (standby time T). An offset image corresponding to is acquired (collected). In the manual image acquisition mode, the drive control unit 102 can acquire from the storage unit 110 an offset image that has been acquired in advance during non-imaging (when radiation is not irradiated). In addition, after capturing a radiographic image in the switched imaging mode, the drive control unit 102 captures an image output from the radiation detection unit 200 (an image based on charges accumulated in a non-irradiated state) after imaging. It can be acquired as an offset image.

  In the use state D, it is assumed that the inspection is being performed, the preparation for the inspection is being performed, and therefore, it is necessary to immediately move to imaging, and stable image quality with little influence of temperature fluctuation is required in imaging. Therefore, it is possible to suppress the influence on the image quality due to the temperature fluctuation or the like while maintaining the state where the imaging preparation drive control 103 can move to imaging at any time. By performing offset correction using an offset image that takes into account the imaging mode before switching, it is possible to reduce the influence of artifacts that may occur due to the effect of the imaging mode before switching.

  Next, an offset correction method according to an embodiment of the present invention will be described with reference to FIGS. 5A, 5B, and 6. FIG. FIG. 5A is a diagram for exemplarily explaining the imaging operation in the embodiment, in which a still image is captured as an imaging mode switched from the imaging mode before switching (pre-driving mode) in the radiation detection unit 200. It is shown as an example.

  In FIG. 5A, a pulse waveform indicates an image readout drive signal controlled by the drive control unit 102. When the first switch (first-stage switch) provided in the operation UI 407 is pressed (ON), the drive control unit 102 switches the imaging mode. The imaging mode that was being driven before the first switch (first stage switch) was pressed ends when the first switch (first stage switch) is pressed, and the switched imaging mode (for example, still image mode). Switching to is performed. When the first switch (first-stage switch) is pressed, the drive control unit 102 performs the imaging preparation drive control 103. After the first switch (first stage switch) is pressed, when the second switch (second stage switch) provided in the operation UI 407 is pressed (ON), the drive control unit 102 ends the imaging preparation drive control 103. The radiographic image acquisition control 105 starts capturing a still image.

  The drive control unit 102 is switched based on the imaging mode switching timing (end of the previous driving mode) acquired based on the first input from the operation UI 407 and the second input from the operation UI 407. The standby time is acquired based on the timing of starting imaging in the imaging mode. The time between the pressing timing (first input) of the first switch (first stage switch) and the pressing timing (second input) of the second switch (second stage switch) varies depending on the user's operation. It's time. The time between the pressing timing of the first switch (first stage switch) and the pressing timing of the second switch (second stage switch) is expressed as a standby time (T) based on an input from the operation UI 407 (operation unit). To do.

  FIG. 6 is a diagram illustrating a configuration of the offset table 118 stored in the storage unit 110. The offset table 118 of the storage unit 110 illustrated in FIG. 6 includes a combination of an imaging mode before switching (a type of the previous drive mode) and a standby time (T), and identification information of an offset image corresponding to this combination. It is associated. Here, the identification information of the offset image is described as “imaging mode before switching (type of previous drive mode) −standby time”. In the offset table 118 shown in FIG. 6, the combination of the imaging mode before switching (the type of the previous drive mode) and the standby time can be arbitrarily set by the user according to the actual use situation.

  Further, the storage unit 110 stores an offset image 112 corresponding to the identification information of the offset image. Based on the identification information of the offset table, the drive control unit 102 acquires an offset image 112 corresponding to a combination of the imaging mode before switching (previous drive mode) and the standby time (T).

  The waiting time (T) is a time that varies depending on the user's operation, and the drive control unit 102 has different offset images corresponding to the different waiting times (Ti) acquired based on the first input and the second input. To get. For example, when the type of the imaging mode (previous drive mode) before switching is “1” and the standby time T = 1 (seconds), the identification information of the offset image is “1-1”, and the identification information “1” The offset image 112 corresponding to “−1” is acquired from the storage unit 110. Similarly, when the type of the imaging mode (previous drive mode) before switching is “1” and the standby time T = 5 (seconds), the identification information of the offset image is “1-5”, and the identification information “ An offset image 112 corresponding to “1-5” is acquired from the storage unit 110.

  In addition, the drive control unit 102 acquires different offset images corresponding to different imaging modes before switching (types of different previous drive modes).

  For example, when the waiting time T = 3 (seconds) and the type of the imaging mode before switching (previous drive mode) is “1”, the identification information of the offset image is “1-3”, and the identification information “1” −3 ”is acquired from the storage unit 110. Similarly, the type of the imaging mode (previous drive mode) before switching is “1”, the standby time T = 3 (seconds), and the type of the imaging mode (previous drive mode) before switching is “4”. In some cases, the identification information of the offset image is “4-3”, and the offset image 112 corresponding to the identification information “4-3” is acquired from the storage unit 110. In the offset table 118, information (1, 2,... N) indicating types of a plurality of imaging modes (pre-driving modes) having different bit rates is provided as the type of the imaging mode (pre-driving mode) before switching. It is remembered. Moreover, although T = 1 to 5 (seconds) is exemplarily shown as the standby time, the gist of the present invention is not limited to this example, and the standby time (Ti corresponding to an arbitrary time) ) Is stored in the offset table 118.

  The drive control unit 102 periodically reads out charges while applying a voltage at the time of imaging to the radiation detection unit 200 by the imaging preparation drive control 103 in the standby time (T). The dark charge accumulated in the pixel is reset.

  In the still image capturing illustrated in FIG. 5A, the drive control unit 102 acquires, from the storage unit 110, the offset image 112 corresponding to the combination of the type of the imaging mode before switching (previous drive mode) and the standby time (T). The offset correction unit 108 corrects the offset component of the radiation image 111 using the acquired offset image 112. According to this configuration, it is possible to reduce the influence of artifacts that may occur due to the influence of the imaging mode before switching by performing offset correction using an offset image that takes into account the imaging mode before switching.

  FIG. 5B is a diagram illustrating an example in which an offset image is acquired under the same conditions as those for capturing a still image after capturing a still image in FIG. 5A. After capturing a radiographic image in the switched imaging mode (still image mode in the example of FIG. 5A), the radiation detection unit 200 outputs an image based on the charge accumulated in a non-irradiated state, and the drive control unit 102 Can acquire an image output from the radiation detection unit 200 as an offset image after imaging. In addition, when acquiring the offset image after imaging, it is not limited to the structure of FIG. 5B, The drive control part 102 may acquire an offset image after abandoning a predetermined pulse number after imaging of a radiographic image. The offset correction unit 108 can correct the offset component of the radiographic image using the offset image corresponding to the combination of the imaging mode before switching and the standby time and the offset image after imaging. The offset image corresponding to the combination of the imaging mode before switching and the standby time is acquired from the storage unit 110 by referring to the offset table 118 as described with reference to FIGS. 5A and 6. In offset correction, the offset component in the radiographic image is corrected with higher accuracy by using the offset image corresponding to the combination of the imaging mode before switching and the standby time and the offset image after imaging. It becomes possible.

  According to the configuration of the present embodiment, it is possible to reduce the influence of artifacts that may occur due to the influence of the imaging mode before switching.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100: radiation imaging apparatus, 101: control unit, 102: drive control unit,
103: imaging preparation drive control, 104: standby drive control,
105: Radiation image acquisition control, 106: Offset image acquisition control,
107: Image processing unit, 108: Offset correction unit,
110: Storage unit, 113: Communication control unit, 114: Usage state monitoring unit,
200: radiation detection unit, 300: radiation generator,
301: Radiation source, 400: Control device, 500: Network

Claims (14)

Radiation detection capable of operating in a plurality of imaging modes and acquiring a radiological image based on the charge accumulated by radiation irradiation based on an imaging mode switched from any one of the plurality of imaging modes A radiation imaging apparatus having means,
Image acquisition means for acquiring an offset image corresponding to a combination of the imaging mode before switching and the standby time from the end of the imaging mode to the start of imaging in the switched imaging mode;
Offset correction means for correcting an offset component of the radiation image using the acquired offset image;
A radiation imaging apparatus comprising:   The image acquisition means is an imaging mode switching timing acquired based on a first input from the operating means and an imaging based on the switched imaging mode acquired based on a second input from the operating means. The radiation imaging apparatus according to claim 1, wherein the standby time is acquired based on a start timing.   2. The storage device according to claim 1, further comprising a storage unit that stores a table in which a combination of the imaging mode before switching, the standby time, and identification information of an offset image corresponding to the combination are associated. The radiation imaging apparatus according to 2.   The radiographic imaging apparatus according to claim 3, wherein an offset image corresponding to identification information of the offset image is stored in the storage unit.   The said image acquisition means acquires the said offset image corresponding to the combination of the imaging mode before the said switching, and the said waiting time based on the identification information of the said table. Radiation imaging device.   The radiographic imaging according to claim 2, wherein the image acquisition unit acquires different offset images corresponding to different standby times acquired based on the first input and the second input. apparatus.   The radiation imaging apparatus according to claim 1, wherein the image acquisition unit acquires different offset images corresponding to different imaging modes before switching. Drive control means for controlling the drive of the radiation detection means,
The drive control means periodically reads out charges while applying a voltage at the time of imaging to the radiation detection means by the imaging preparation drive control during the standby time, and accumulates it in each pixel of the radiation detection means. The radiation imaging apparatus according to claim 1, wherein dark charges to be reset are reset. After capturing a radiographic image in the switched imaging mode, the radiation detection means outputs an image based on the charge accumulated in a non-irradiated state,
The radiation imaging apparatus according to claim 1, wherein the image acquisition unit acquires the image output from the radiation detection unit as an offset image after imaging.   The offset correction means corrects an offset component of the radiographic image using an offset image corresponding to a combination of the imaging mode before switching and the standby time, and the offset image after imaging. The radiation imaging apparatus according to claim 9. Based on information indicating the state of the radiation imaging apparatus, further comprising a state monitoring means for determining the usage state of the radiation imaging apparatus,
The image acquisition means, based on the determination result of the state monitoring means, an offset image corresponding to a combination of the standby time based on the first input and the second input from the operation means and the imaging mode before the switching The radiation imaging apparatus according to claim 1, further comprising:   A radiation imaging system comprising the radiation imaging apparatus according to claim 1. Radiation detection capable of operating in a plurality of imaging modes and acquiring a radiological image based on the charge accumulated by radiation irradiation based on an imaging mode switched from any one of the plurality of imaging modes A radiation imaging method for a radiation imaging apparatus having means,
Obtaining an offset image corresponding to a combination of the imaging mode before switching and the standby time from the end of the imaging mode to the start of imaging in the switched imaging mode;
Correcting the offset component of the radiation image using the acquired offset image;
A radiation imaging method comprising:   A program for causing a computer to execute each step of the radiation imaging method according to claim 13.

Images