Radiation imaging device, radiation imaging system, control device, control method, and program

Abstract

To provide a technique advantageous for properly detecting irradiation of radiation to an imaging region regardless of a rotation angle of the imaging region with respect to a subject in a radiation imaging apparatus.SOLUTION: A radiation imaging apparatus comprises: an imaging region for generating a signal for acquiring a radiation image according to the incident radiation; a control unit for setting a detection region used for detecting the radiation separately from the acquisition of the radiation image in the imaging region; and a rotation detection unit. When the imaging region is arranged so as to face the subject, the rotation detection unit detects the rotation angle of a reference part of the imaging region with respect to the reference azimuth of the subject about an axis in the normal direction of the imaging region. The control unit decides a side located in the same direction as the reference azimuth of the subject among the plurality of sides defining the outer edge of the imaging region in accordance with the imaging object portion and the rotation angle of the subject, sets the detection region at a position apart by a predetermined distance for imaging the imaging object portion from the side, and performs control of the imaging on the basis of the dose of the radiation incident on the detection region.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a radiation imaging apparatus, a radiation imaging system, a control apparatus, a control method, and a program. [Background technology]

[0002] In medical image diagnosis and non-destructive testing, radiation imaging devices using flat panel detectors (FPDs) made of semiconductor materials are widely used. It is known that such radiation imaging devices monitor radiation incident on the radiation imaging device. Patent Document 1 shows a radiation imaging device equipped with a rotation detection unit that detects the direction of a side 5001 of a rectangular radiation imaging device 1001 as seen from the subject 1011 side, as shown in FIG. 4. The radiation imaging device 1001 of Patent Document 1 selects an area to be used for radiation detection from among a plurality of areas 5005 set for detecting radiation, based on the imaging site of the subject and the direction of the radiation imaging device 1001 as seen from the subject side, detected by the rotation detection unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-127444 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, as shown in Fig. 4, a case where the radiation imaging device 1001 is fixed to a gantry 5004 or the like and imaging is performed in an upright position is considered. In this case, four states are possible: a first state in which the side 5001 of the radiation imaging device 1001 is the left side when viewed from the subject 1011 side; a second state in which the radiation imaging device 1001 is rotated 90° counterclockwise from the first state; a third state in which the radiation imaging device 1001 is further rotated 90° counterclockwise from the second state; and a fourth state in which the radiation imaging device 1001 is rotated 90° counterclockwise from the third state. In this case, as shown in Fig. 4, the distance from the side 5011 on the head side of the subject 1011 in upright imaging of the radiation imaging device 1001 to the area closest to the side 5011 among multiple areas (detection areas 5005) for detecting radiation may differ between the first state and the second state. Similarly, the distance from the side 5011 on the head side of the subject 1011 in upright imaging by the radiation imaging device 1001 to the area closest to the side 5011 among the multiple areas for detecting radiation may differ between the first state and the fourth state, and between the third state and the fourth state. When the radiation imaging device 1001 is fixed to the gantry 5004 in the first state, if the subject is placed in accordance with the radiation imaging device 1001 fixed to the gantry 5004 in the orientation of the second state, the area used for detecting radiation irradiation may be shifted from the target part of the subject. If the position of the radiation irradiation detection area and the target part of the subject is shifted, the accuracy of detecting radiation irradiation may decrease.

[0005] An object of the present invention is to provide an advantageous technique for properly detecting irradiation of an imaging region with radiation, regardless of the rotation angle of the imaging region with respect to a subject, in a radiation imaging apparatus. [Means for solving the problem]

[0006] In consideration of the above-mentioned problems, a radiation imaging device according to an embodiment of the present invention is a radiation imaging device including: an imaging area in which a plurality of pixels are arranged that generate signals for acquiring a radiation image in response to incident radiation; a control unit for setting a detection area which is an area used for detecting the radiation separately from acquiring the radiation image in the imaging area; and a rotation detection unit, wherein when the imaging area is arranged to face a subject, the rotation detection unit detects a rotation angle of a reference part of the imaging area relative to a reference orientation of the subject around an axis in a normal direction of the imaging area, and the control unit determines, in accordance with a target part of the subject and the rotation angle, a side which is located in the same direction as the reference orientation of the subject among a plurality of sides defining an outer edge of the imaging area, and sets the detection area at a position separated by a predetermined distance from the side for imaging the target part, and controls imaging based on a dose of radiation incident on the detection area. Effect of the Invention

[0007] The above means provides an advantageous technique for properly detecting irradiation of an imaging region with radiation, regardless of the rotation angle of the imaging region with respect to a subject, in a radiation imaging apparatus. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of the arrangement of a radiation imaging system using a radiation imaging apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of the appearance of the radiation imaging apparatus in FIG. 1; [Diagram 3] 2 is a diagram showing an example of a circuit configuration of the radiation imaging apparatus shown in FIG. 1; [Figure 4] 2 is a diagram for explaining upright position imaging using the radiation imaging system of FIG. 1; [Diagram 5] 2A to 2C are diagrams for explaining a method of setting a detection region of the radiation imaging apparatus of FIG. 1; [Figure 6] 2A to 2C are diagrams for explaining a method of setting a detection region of the radiation imaging apparatus of FIG. 1; [Figure 7] 2A to 2C are diagrams for explaining a method of setting a detection region of the radiation imaging apparatus of FIG. 1; [Figure 8] 2 is a flow diagram of upright position imaging performed by the radiation imaging apparatus of FIG. 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] Furthermore, radiation in the present invention may include α-rays, β-rays, γ-rays, and other beams produced by particles (including photons) emitted by radioactive decay, as well as beams having the same or greater energy, such as X-rays, particle beams, and cosmic rays.

[0011] The configuration and operation of a radiation imaging apparatus and a radiation imaging system according to the present embodiment will be described with reference to Figs. 1 to 8. Fig. 1 shows an example of the configuration of a radiation imaging system 1000 using a radiation imaging apparatus 1001 according to the present embodiment. The radiation imaging system 1000 can be used, for example, to capture radiation images in a hospital. The radiation imaging system 1000 includes the radiation imaging apparatus 1001, a control device 1002, a radiation source 1003, a radiation generating device 1004, an in-hospital LAN 1005, and an exposure switch 1006.

[0012] The radiation imaging apparatus 1001 detects radiation transmitted through a subject 1011, which is a patient or a subject, and generates a signal for forming an image. The control device 1002 is communicably connected to the radiation imaging apparatus 1001 and the radiation generating apparatus 1004. The control device 1002 can perform, for example, setting imaging conditions and controlling the operation of the radiation imaging apparatus 1001. The radiation imaging apparatus 1001 can perform, for example, transfer of image signals, transmission of information on the dose of incident radiation, and transmission of signals for implementing automatic exposure control (AEC) to the control device 1002. In this embodiment, the control device 1002 has, for example, a mouse and a keyboard as input devices that enable setting of imaging conditions, operation control, and input of information such as image information, and also has a display as an output device. The control device 1002 can also perform, for example, radiation irradiation control for the radiation generating apparatus 1004 that generates radiation from a radiation source 1003. The control device 1002 can be a device for controlling the radiation imaging device 1001 and a radiation generating device 1004 for irradiating the radiation imaging device 1001 with radiation.

[0013] The radiation source 1003 includes, for example, a radiation tube (X-ray tube) that accelerates electrons with a high voltage and causes them to collide with an anode in order to generate radiation, and a rotor. The exposure switch 1006 requests the control device 1002 to emit radiation when the user turns it on by pressing the switch or performing other operations.

[0014] The control device 1002 includes a communication control unit 1021 that controls communication, and a control unit 1022 that performs operation control, dose control, etc. The communication control unit 1021 may be configured as a unit separate from the control device 1002. The control unit 1022 monitors the states of the radiation imaging device 1001 and the radiation generation device 1004, and controls radiation irradiation and imaging. The radiation irradiated from the radiation source 1003 is irradiated onto an object. The radiation imaging device 1001 detects the radiation irradiated from the radiation source 1003 and transmitted through the object, and generates a signal for forming an image.

[0015] The radiation imaging device 1001 includes a wireless communication unit and a wired communication unit (not shown), and can communicate with the communication control unit 1021 of the control device 1002. The wired communication unit enables information exchange with the communication control unit 1021 of the control device 1002 by a cable connection according to a known communication standard. The wireless communication unit also includes, for example, a circuit board including a communication IC and the like. The circuit board including the communication IC and the like is electrically connected to an antenna (not shown), and the antenna transmits and receives radio waves. The circuit board including the communication IC and the like performs communication processing of a protocol based on a wireless LAN via the antenna. There is no particular limitation on the frequency band, standard, or method of wireless communication in the wireless communication, and a method such as a known close-proximity wireless or UWB may be used. The wireless communication unit may have a plurality of wireless communication methods, and may perform communication by appropriately selecting one of them. Only one of the wired communication unit and the wireless communication unit may be provided. Any configuration may be used between the radiation imaging device 1001 and the control device 1002 as long as communication is possible.

[0016] Between the control device 1002 and the radiation imaging device 1001, settings of imaging conditions, operation control, transfer of image signals, the reaching dose of radiation incident on the radiation imaging device 1001, AEC signals, etc. are exchanged. Furthermore, between the control device 1002 and the radiation generation device 1004, dose information, irradiation control signals, etc. are exchanged. Here, dose information refers to the dose of radiation irradiated from the radiation source 1003. The reaching dose refers to the dose of radiation irradiated from the radiation source 1003 that reaches the radiation imaging device 1001.

[0017] The radiation imaging device 1001 may be, for example, a portable cassette-type flat panel detector. FIG. 2 shows an external view of the radiation imaging device 1001 in the embodiment. The radiation imaging device 1001 includes a power button 1007 for turning the power on and off, a battery unit 1008 for supplying power, and a connector 1009. For example, the battery unit 1008 is removable, and the battery body can be charged by a battery charger. The radiation imaging device 1001 may be connected to the control device 1002 via a sensor cable 1010. In this case, one end of the sensor cable 1010 is connected to the radiation imaging device 1001 via the connector 1009. When the radiation imaging device 1001 and the control device 1002 are connected via the sensor cable 1010, communication between the radiation imaging device 1001 and the control device 1002 is switched to wired communication automatically or by a user's operation, and information is exchanged between them via wired communication. In this manner, in this embodiment, the radiation imaging apparatus 1001 and the control device 1002 are configured as separate devices, but the present invention is not limited to this. The radiation imaging apparatus 1001 may be configured as an integrated device including a control unit having the functions of the control device 1002. When the radiation imaging apparatus 1001 includes the functions of the control device 1002, the control unit of the radiation imaging apparatus 1001 may be configured, for example, with an ASIC.

[0018] FIG. 3 shows an example of the internal configuration of a radiation imaging device 1001 in this embodiment. The radiation imaging device 1001 has a plurality of pixels 101 arranged in a matrix shape to form a plurality of rows and a plurality of columns in an imaging region 100, which generate signals corresponding to incident radiation. The plurality of pixels 101 are arranged to generate signals for acquiring a radiation image. In addition, a detector element 121 for detecting radiation incident on the imaging region 100 is arranged in the imaging region 100. The pixel 101 includes a conversion element 102 for converting radiation into an electric signal, and a switch 103 arranged between a column signal line 106 and the conversion element 102. The detector element 121 includes a conversion element 122 for converting radiation into an electric signal, and a switch 123 arranged between a detection signal line 125 and the conversion element 122. In this embodiment, as shown in FIG. 3, a plurality of detector elements 121 for detecting radiation incident on the imaging region 100 are arranged in addition to a plurality of pixels 101 for forming a radiation image. For example, the signal output from the detector element 121 does not have to be used as a signal indicating the luminance of the pixel in the radiation image at the position where the detector element 121 is arranged. However, this is not limited to this, and the detector element 121 may not be arranged separately from the pixel 101, and some of the multiple pixels 101 may function as the detector element 121.

[0019] The conversion element 102 and the conversion element 122 may be composed of a scintillator that converts radiation into light and a photoelectric conversion element that converts light into an electrical signal. The scintillator is generally formed in a sheet shape so as to cover the imaging region 100, and may be shared by a plurality of pixels 101 and detector elements 121. The conversion element 102 and the conversion element 122 may be composed of a conversion element that directly converts radiation into an electrical signal. The switch 103 and the switch 123 may include, for example, a thin film transistor (TFT) whose active region is composed of a semiconductor such as amorphous silicon or polycrystalline silicon.

[0020] The radiation imaging device 1001 includes a plurality of column signal lines 106 and a plurality of driving lines 104. Each of the plurality of column signal lines 106 corresponds to one of a plurality of columns in the imaging region 100. Each of the plurality of driving lines 104 corresponds to one of a plurality of rows in the imaging region 100. Each of the plurality of driving lines 104 is driven by a driving circuit 221.

[0021] One of the two electrodes of the conversion element 102 is connected to one of the two main electrodes of the switch 103, and the other electrode of the conversion element 102 is connected to a bias line 108. As shown in FIG. 3, the bias line 108 extends in the column direction and can be commonly connected to the multiple conversion elements 102 arranged in the column direction. The bias line 108 receives a bias voltage Vs from a power supply circuit 226 and supplies it to each conversion element 102. The other main electrodes of the switches 103 of the multiple pixels 101 constituting one column are connected to one of the multiple column signal lines 106. The control electrodes of the switches 103 of the multiple pixels 101 constituting one row are connected to one of the multiple drive lines 104.

[0022] The column signal lines 106 are connected to a readout circuit 222. The readout circuit 222 may include a plurality of detection units 132, a multiplexer 134, and an AD converter 136. Each of the column signal lines 106 is connected to a corresponding one of the detection units 132 of the readout circuit 222. In this embodiment, one column signal line 106 corresponds to one detection unit 132. The detection unit 132 includes, for example, a differential amplifier. The multiplexer 134 selects the detection units 132 in a predetermined order, and supplies a signal output from the selected detection unit 132 to the AD converter 136. The AD converter 136 converts the supplied analog signal into a digital signal and outputs the digital signal.

[0023] One of the two electrodes of the conversion element 122 is connected to one of the two main electrodes of the switch 123, and the other electrode of the conversion element 122 is connected to the bias line 108. The other main electrode of the switch 123 is electrically connected to a detection signal line 125. A control electrode of the switch 123 is electrically connected to a drive line 124. The radiation imaging device 1001 may have a plurality of detection signal lines 125. One or more detection elements 121 may be connected to one detection signal line 125. The drive line 124 is driven by a drive circuit 241. One or more detection elements 121 may be connected to one drive line 124.

[0024] The detection signal line 125 is connected to the readout circuit 242. The readout circuit 242 may include a plurality of detection units 142, a multiplexer 144, and an AD converter 146. Each of the plurality of detection signal lines 125 may be connected to a corresponding one of the plurality of detection units 142 of the readout circuit 242. In this embodiment, one detection signal line 125 corresponds to one detection unit 142. The detection unit 142 includes, for example, a differential amplifier. The multiplexer 144 selects the plurality of detection units 142 in a predetermined order, and supplies a signal output from the selected detection unit 142 to the AD converter 146. The AD converter 146 converts the supplied analog signal into a digital signal and outputs the digital signal.

[0025] The output of the readout circuit 242 (AD converter 146) is supplied to the signal processing unit 224 and processed by the signal processing unit 224. The signal processing unit 224 outputs information indicating irradiation of radiation to the radiation imaging device 1001 based on the output of the readout circuit 242 (AD converter 146). Specifically, the signal processing unit 224 may detect, for example, whether or not radiation has been irradiated to the radiation imaging device 1001, and may calculate at least one of the amount of radiation (dose) and the accumulated amount of radiation (accumulated amount of dose). The control unit 225 controls the driving circuit 221, the driving circuit 241, and the readout circuit 242 based on the information from the signal processing unit 224. The control unit 225 controls, for example, the start and end of exposure (accumulation of charges by the pixels 101 corresponding to the irradiated radiation) based on the information from the signal processing unit 224. The communication unit 227 is responsible for communication with the control device 1002. The communication unit 227 may have two communication units, a wired communication unit and a wireless communication unit, for communicating with the control device 1002. As described above, in this embodiment, the detector element 121 is arranged independently of the pixel 101. However, the pixel 101 and the detector element 121 may have the same structure and be controlled using the same drive circuit and readout circuit.

[0026] Next, the rotation of the imaging region 100 of the radiation imaging device 1001 with respect to the reference orientation of the subject will be described with reference to the case of performing upright imaging. When performing upright imaging of the subject, the radiation imaging device 1001 is fixed to a stand 5004 or the like and installed upright. FIG. 4 shows an example of the configuration of the radiation imaging system 1000 when performing upright imaging of the subject 1011. The radiation imaging device 1001 can be installed on the stand 5004 in, for example, four orientations. One is a first state in which the side 5001 of the radiation imaging device 1001 is the left side when viewed from the subject side 1011. The other is a second state in which the radiation imaging device 1001 is rotated 90° counterclockwise with respect to the first state, and the side 5001 of the radiation imaging device 1001 is the bottom side. Similarly, although not shown in Figure 4, the radiation imaging device 1001 can be installed on the stand 5004 in a third state in which the radiation imaging device 1001 is further rotated 90 degrees counterclockwise from the second state so that side 5001 becomes the right side, and in a fourth state in which the radiation imaging device 1001 is rotated 90 degrees counterclockwise from the third state so that side 5001 becomes the top side.

[0027] Further, in the imaging region 100 of the radiation imaging device 1001, a plurality of detection areas 5005 are set in advance, each of which includes a detector element 121 and detects incident radiation. There is no limitation on the number or arrangement of the detection areas 5005, and each of the detection areas 5005 may correspond to each of the assumed imaging target parts. Here, for the sake of simplicity, it is assumed that five detection areas 5005 are set in advance as shown in FIG. 4. The five detection areas 5005 are, in the first state shown in FIG. 4, a detection area A located at the upper left, a detection area B located at the upper right, a detection area C located at the center, a detection area D located at the lower left, and a detection area E located at the lower right, as viewed from the subject 1011 side. Hereinafter, when a specific detection area is indicated, it is indicated by adding the symbols A to E, such as "detection area A", and when a specific detection area is not indicated, it is indicated as "detection area 5005".

[0028] In each detection area 5005, incident radiation is detected, and for example, control such as AEC is performed in the radiation imaging device 1001 (radiation imaging system 1000). The control unit 225 of the radiation imaging device 1001 or the control device 1002 may control the radiation generation device 1004 based on the dose of radiation detected in the radiation detection area 5005 in the imaging region 100. For example, the control device 1002 may control the radiation generation device 1004 based on the arrival dose detected in each detection area 5005 so as not to irradiate excess radiation from the radiation source 1003. However, the optimal arrival dose differs depending on the imaging target site of the subject 1011. In addition, when the orientation of the radiation imaging device 1001 is in each of the first to fourth states, the position of the detection area 5005 with respect to the imaging target site of the subject 1011 positioned with respect to the gantry 5004 may change. Therefore, the radiation imaging apparatus 1001 of this embodiment includes a rotation detection unit 5003 that detects a rotation angle of a reference part of the imaging area 100 with respect to a reference orientation of the subject 1011 around an axis in the normal direction of the imaging area 100 when the imaging area 100 is disposed to face the subject 1011. The control unit 225 of the radiation imaging apparatus 1001 sets a detection area of ​​radiation in the imaging area 100 according to an imaging target part 5006 of the subject 1011 and the rotation angle detected by the rotation detection unit 5003. For example, the control unit 225 selects an appropriate detection area (e.g., detection area A) from the above-mentioned multiple detection areas 5005, and adjusts the position of the selected detection area A to set the detection area of ​​radiation. This reduces the possibility that the detection area, which is an area used for detecting irradiation of radiation separately from obtaining a radiation image, may deviate from the target part of the subject 1011. In other words, excessive radiation irradiation or insufficient radiation irradiation from the radiation source 1003 can be suppressed, and a radiological image using an appropriate dose can be obtained.

[0029] As shown in Fig. 4, in this specification, a case will be described in which the chest is imaged as the imaging target part 5006 of the subject 1011 in upright position imaging. For this reason, the reference orientation of the subject 1011, which is the reference for rotation of the imaging region 100 of the radiation imaging device 1001, will be described as a direction toward the head of the subject 1011. Also, a reference part for obtaining a rotation angle of the imaging region 100 of the radiation imaging device 1001 with respect to the reference orientation of the subject 1011 will be described as the side 5001 on the left side as seen from the subject 1011 in the above-mentioned first state. However, this is not limited to this, and the present embodiment described below can be applied to imaging in a supine position and other imaging target parts such as the head, abdomen, and placenta. That is, the respective functions of the radiation imaging apparatus 1001 and the radiation imaging system 1000 described in this embodiment can be realized by appropriately setting the reference portion of the radiation imaging apparatus 1001 and the reference orientation of the subject 1011 according to the positioning of the subject 1011 and the part to be imaged when imaging is performed using the radiation imaging apparatus 1001. As described above, the radiation imaging apparatus 1001 can be placed on the gantry 5004 in four states, the first state to the fourth state, but the following description focuses on the first state and the second state.

[0030] 4, the radiation imaging device 1001 is fixed to a stand 5004 so as to be aligned with the position of an imaging target part 5006 of a subject 1011. The radiation imaging device 1001 also includes an imaging region 100 in which the above-mentioned five detection areas 5005 are set in advance as a radiation detection region. The radiation imaging device 1001 also includes a rotation detection unit 5003 for detecting a rotation angle of a reference part (side 5001 in this embodiment) of the imaging region 100 relative to a reference orientation of the subject 1011 (direction toward the head in this embodiment) around an axis in the normal direction of the imaging region 100.

[0031] The rotation detection unit 5003 may detect the rotation angle of the side 5001, which is the reference part, by detecting the orientation of the side 5001, which is the reference part, with respect to the vertical direction. In this case, for example, the rotation detection unit 5003 may be an acceleration sensor that detects acceleration in the gravity direction. When the rotation detection unit 5003 includes a one-axis acceleration sensor, the acceleration sensor may be installed so that the output is large in the first state and the output is small in the second state. Also, for example, when the rotation detection unit 5003 includes a two-axis acceleration sensor, the acceleration sensor may be installed so that the output is large for the first axis in the first state and the output is large for the second axis in the second state. Also, the rotation detection unit 5003 may include a three-axis acceleration sensor.

[0032] Also, for example, the rotation detection unit 5003 may detect a rotation angle of the side 5001, which is a reference part, by detecting a detection object fixed to the gantry 5004 on which the radiation imaging device 1001 is attached. In this case, the detection object may be a convex-shaped object (for example, a protrusion) arranged at a predetermined position on the gantry 5004. The rotation detection unit 5003 may include a pressure sensor that detects a pressure pressed by the protrusion arranged as the detection object, so that the rotation angle of the side 5001, which is a reference part, can be detected. Similarly, the rotation detection unit 5003 may have a convex shape, and a recess may be provided as the detection object at a predetermined position on the gantry 5004. Also, for example, a magnetic body such as a magnet may be arranged on the gantry 5004 as the detection object, and the rotation detection unit 5003 may be a magnetic sensor. When the radiation imaging device 1001 is set on the gantry 5004, the magnetic sensor, which is the rotation detection unit 5003, detects a magnetic material arranged at a predetermined position on the gantry 5004, thereby detecting the rotation angle of the side 5001, which is the reference part.

[0033] In this way, when the imaging region 100 is disposed to face the subject 1011, the rotation detection unit 5003 can detect the rotation angle of the reference portion of the imaging region 100 with respect to the reference orientation of the subject 1011 around the axis in the normal direction of the imaging region 100. The radiation imaging device 1001 outputs information on the rotation angle detected by the rotation detection unit 5003 to the control unit 225, and the control unit 225 generates information on the detection area 5005 to be used (information designating whether each detection area is valid / invalid). Here, a case will be described in which the control unit 225 of the radiation imaging device 1001 sets the detection area 5005, but these controls may be performed by the control device 1002. Similarly, the controls described below will be described as being controlled by the control unit 225, but may be controlled by the control device 1002. After setting the detection area 5005 to be used as a radiation detection area, the control unit 225 of the radiation imaging device 1001 controls imaging based on the dose of incident radiation, based on information about the detection area 5005 to be used as a detection area. For example, the control unit 225 outputs information about the reaching dose in the detection area 5005 to be used as a detection area to the control device 1002.

[0034] 5 is a diagram focusing on the imaging region 100 in the configuration example of the radiation imaging system 1000 shown in FIG. 4. FIG. 5 shows the positions of the detection areas 5005 preset in the imaging region 100 when the radiation imaging device 1001 is stored in the gantry 5004 in the first state and the second state in the case of imaging in a standing position. In the first state, the detection areas A and B used as the detection region in chest imaging are located at a distance 5501 from a side 5011 (upper side in this case) located in the same direction as the direction toward the head, which is the reference orientation of the subject 1011, among the multiple sides defining the outer edge of the imaging region 100. Similarly, in the second state, the detection areas B and E used as the detection region in chest imaging are located at a distance 5502 from a side 5011 (upper side) located in the same direction as the direction toward the head, which is the reference orientation of the subject 1011, among the multiple sides defining the outer edge of the imaging region 100.

[0035] In this way, the position of the detection area 5005 used as the detection area of ​​radiation when imaging the chest in a standing position may differ between the first state and the second state. In the case shown in FIG. 5, the distance from the side 5011 in the first state to the detection areas A and B used as the detection area and the distance from the side 5011 in the second state to the detection areas B and E used as the detection area are shifted by a distance 5503. In other words, when the radiation imaging device 1001 is fixed to the gantry 5004 in the first state, if the subject 1011 is placed in accordance with the radiation imaging device 1001 fixed to the gantry 5004 in the orientation of the second state, the detection area 5005 used as the detection area of ​​radiation may be shifted from the target part of the subject 1011. For example, when imaging the chest, the chin of the subject 1011 may be placed in accordance with the upper part of the gantry 5004. Therefore, the distance from the upper part of the gantry 5004 to the chest is approximately constant. On the other hand, when the radiation imaging device 1001 is stored with its upper part flush with the gantry 5004, the distance from the upper part of the gantry 5004 to the detection areas A and B in the first state and the distance from the upper part of the gantry 5004 to the detection areas B and E in the second state will differ by a distance 5503. If the positional relationship between the radiation detection area and the target part of the subject 1011 is shifted, there is a possibility that the accuracy of control such as AEC performed by detecting the irradiation of radiation will decrease.

[0036] Therefore, in this embodiment, the control unit 225 (or the control device 1002) of the radiation imaging device 1001 first determines, among the multiple sides defining the outer edge of the imaging region 100, a side 5011 located in the same direction as the reference orientation of the subject 1011, in accordance with the imaging target part 5006 of the subject 1011 and the rotation angle detected by the rotation detection unit 5003. In this embodiment, the imaging target part 5006 of the subject is the chest. Therefore, from information on the rotation angle of the side 5001, which is the reference part of the imaging region 100 detected by the rotation detection unit 5003, the control unit 225 can determine the side 5011 corresponding to the upper side as the direction toward the head, which is the reference orientation of the subject 1011.

[0037] Next, the control unit 225 sets a detection area at a position separated from the side 5011 by a predetermined distance (for example, distance 5501) for imaging the imaging target part 5006. Specifically, from the rotation angle detected by the rotation detection unit 5003, the control unit 225 selects a detection area 5005 to be used as the detection area from among the multiple detection areas 5005 according to the imaging target part 5006 and the rotation angle. In the case of imaging the chest, for example, the control unit 225 may select, from among the multiple detection areas 5005, the detection area 5005 closest to the side 5011, which is the upper side as seen from the subject 1011, as the detection area to be used as the detection area. Next, the control unit 225 adjusts the position of the selected detection area 5005 so that the position of the selected detection area 5005 is separated from the side 5011 by a predetermined distance.

[0038] In the first state, the control unit 225 selects the detection areas A and B as the detection areas 5005 to be used as the detection area, and since the detection areas A and B are separated from the side 5011 by a distance 5501 that is predetermined for imaging the chest, it is not necessary to adjust the positions. In the second state, the control unit 225 selects the detection areas B and E as the detection areas 5005 to be used as the detection area. Next, the detection areas B and E are located at a distance 5502 away from the side 5011, not the distance 5501 that is predetermined for imaging the chest. Therefore, the control unit 225 adjusts the positions of the detection areas B and E to be used as the detection area to a position 5010 that is separated by a distance 5501 from the side 5011, which is the upper side in the second state. In this embodiment, it has been described that the position of the preset detection area 5005 is adjusted to an appropriate position as the detection area, but the control unit 225 may directly set an appropriate position as the detection area.

[0039] In this way, irradiation of radiation is detected in the detection region set by the control unit 225, and the control unit 225 controls imaging based on the dose of radiation incident on the detection region. For example, the control unit 225 may obtain an integrated value of the dose of radiation incident on the detection region, and when the integrated value exceeds a predetermined threshold, may supply a signal to the radiation generating device 1004 to stop irradiation of radiation. In this case, the control unit 225 may supply a signal to the control device 1002 to stop irradiation of radiation based on information on the integrated value, and in response to this signal, the control device 1002 may supply a signal to the radiation generating device 1004 to stop irradiation of radiation. Also, for example, the control unit 225 may transmit information on the dose of radiation incident on the detection region to the control device 1002, and supply a signal to the radiation generating device 1004 to stop irradiation of radiation based on the dose information received by the control device 1002.

[0040] In this embodiment, the control unit 225 sets the detection region at a position spaced from the side 5011 by a predetermined distance for imaging the imaging target region 5006 in accordance with the imaging target region 5006 of the subject 1011 and the rotation angle. This allows the position of the detection area 5005 used as the radiation detection region to coincide with the imaging target region 5006 of the subject 1011 positioned relative to the gantry 5004, regardless of the rotation angle of the imaging region 100 as viewed from the subject 1011. This prevents misalignment between the radiation detection region and the imaging target region 5006 of the subject 1011, thereby preventing a decrease in the accuracy of detecting irradiation of radiation. In other words, a radiation imaging device 1001 that properly detects irradiation of radiation to the imaging region 100, regardless of the rotation angle of the imaging region 100 relative to the subject 1011, can be realized.

[0041] As described above, a plurality of detector elements 121 for detecting incident radiation are arranged in the imaging region 100. The control unit 225 detects the incident radiation using the detector elements 121 arranged in the detection area 5005 used as the detection region among the plurality of detector elements 121. Fig. 6 is a diagram for explaining a method for adjusting the detection area 5005 used as the radiation detection region in the horizontal direction relative to the drive line 124. When adjusting the detection region in the horizontal direction, the position of the detection region may be adjusted by changing the range of the signals of the detector elements 121 read out by the readout circuit 242 that are used for detecting irradiation of radiation.

[0042] For example, it is assumed that signals output from the detector elements 121 via the detection signal lines 125-3 to 125-6 among the detection signal lines 125 connected to the detector 142 are used as the preset detection area A. When the detection area A is moved horizontally to the left position 5010a, the range used for detecting the irradiation of radiation is changed to signals output from the detector elements 121 via the detection signal lines 125 with smaller numbers after the hyphen, such as the detection signal lines 125-1 to 125-4. When the detection area A is moved horizontally to the right position 5010b, the range used for detecting the irradiation of radiation is changed to signals output from the detector elements 121 via the detection signal lines 125 with larger numbers after the hyphen, such as the detection signal lines 125-5 to 125-8. This makes it possible to adjust the radiation detection region to an appropriate position for the preset detection area A. In this way, the controller 225 controls the imaging based on signals output from the detector elements 121 arranged in the detection region (set as the detection region) among the multiple detector elements 121. On the other hand, the control unit 225 does not need to use signals output from the detector elements 121 that are not arranged in the detection region among the multiple detector elements 121 for controlling imaging.

[0043] It is also possible to change the range of the detection signal lines 125 used when detecting irradiation of radiation on both the left and right sides to enlarge or reduce the size of the radiation detection region itself. For example, for a preset detection area A, the detection region can be expanded in the horizontal direction by setting the range used for detecting irradiation of radiation to signals output from the detection elements 121 via the detection signal lines 125-2 to 125-7. Conversely, for a preset detection area A, the detection region can be reduced in the horizontal direction by setting the range used for detecting irradiation of radiation to signals output from the detection elements 121 via the detection signal lines 125-4 to 125-5.

[0044] 7 is a diagram illustrating a method for adjusting the detection area 5005 used as a radiation detection region in a vertical direction relative to the driving lines 124. When adjusting the detection region in the vertical direction, the position of the detection region may be adjusted by changing the driving lines 124 driven by the driving circuit 241.

[0045] For example, it is assumed that the signal output from the detector element 121 by driving the drive lines 124-3 to 125-8 of the drive lines 124 connected to the drive circuit 241 is used as the preset detection area A. When the detection area A is vertically moved to the upper position 5010a, the range used for detecting the irradiation of radiation is changed to the signal output from the detector element 121 by driving the drive lines 124 with smaller numbers after the hyphen, such as the drive lines 124-1 to 124-6. Also, when the detection area A is vertically moved to the lower position 5010b, the range used for detecting the irradiation of radiation is changed to the signal output from the detector element 121 by driving the drive lines 124 with larger numbers after the hyphen, such as the drive lines 124-5 to 124-10. This makes it possible to adjust the radiation detection region to an appropriate position for the preset detection area A. In this way, the control unit 225 controls the imaging by outputting a signal from the detector element 121 arranged in the detection region (set as the detection region) among the multiple detector elements 121. On the other hand, the control unit 225 may not output signals from the detector elements 121 that are not arranged in the detection region among the multiple detector elements 121.

[0046] It is also possible to change the range of drive lines 124 that are driven when detecting irradiation of radiation on both the top and bottom sides, thereby expanding or reducing the size of the radiation detection region itself. For example, for a preset detection area A, the range used to detect irradiation of radiation is set as a signal output from detection element 121 by driving drive lines 124-2 to 124-9. This makes it possible to expand the detection region in the vertical direction. Conversely, for a preset detection area A, the range used to detect irradiation of radiation is set as a signal output from detection element 121 by driving drive lines 124-4 to 124-4. This makes it possible to reduce the detection region in the vertical direction.

[0047] By combining the horizontal and vertical adjustments of the preset detection area 5005, it is also possible to change the range used as the detection area in an oblique direction. The shape of the detection area 5005 (detection area) is not limited to a square as shown in Figs. 5 to 7. The shape of the detection area 5005 (detection area) may be a rectangular shape such as a rectangle, a polygon, or a substantially round shape, as well as a square. The shape of the imaging area is not limited to a rectangle as shown in Figs. 5 to 7, and may be a square or the like. The arrangement of the drive circuit 241 is not limited to being connected to the long side of the imaging area 100 as shown in Figs. 5 to 7, and may be connected to the short side. In this case, the readout circuit 242 may be connected to the long side of the imaging area 100.

[0048] 8 is a flow chart showing the operation procedure of the control unit 225 (control device 1002) in this embodiment. First, the user sets the radiation imaging device 1001 on a stand 5004 for standing position imaging, and aligns the subject 1011 with the stand 5004. This positions the imaging region 100 facing the subject 1011. In addition, the user uses the control device 1002 as an input device to set the chest as the imaging target region 5006 of the subject 1011 (S1).

[0049] Next, the control unit 225 (control device 1002) causes the rotation detection unit 5003 to detect a rotation angle of a reference part of the imaging region 100 with respect to a reference orientation of the subject 1011, around an axis in the normal direction of the imaging region 100. Since the subject 1011 is stored on a stand 5004 for standing position imaging and the chest is set as the imaging target part, the rotation detection unit 5003 detects a rotation angle of the side 5001 with respect to a direction toward the head of the subject 1011, and transmits the orientation of the imaging region 100 to the control unit 225 (control device 1002) (S2).

[0050] Upon receiving the information on the rotation angle from the rotation detector 5003, the controller 225 (controller 1002) sets a detection region for detecting irradiation of radiation according to the portion 5006 to be imaged of the subject 1011 and the rotation angle. First, the controller 225 (controller 1002) determines the state of the relationship between the imaging region 100 and the subject 1011 (S3). Then, the controller 225 (controller 1002) determines a side that is located in the same direction as the reference orientation of the subject 1011, among the multiple sides that define the outer edge of the imaging region 100. Next, a detection region is set at a position spaced a predetermined distance from the determined side for imaging the portion 5006 to be imaged.

[0051] More specifically, it is assumed that the control unit 225 (control device 1002) determines that the imaging target area 5006 is in the first state based on the rotation angle detected by the rotation detection unit 5003 and the imaging target area 5006. In this case, the control unit 225 (control device 1002) selects, as the detection area, detection areas A and B adjacent to side 5011 which is the upper side of the imaging area 100 as seen from the subject 1011, in accordance with the imaging target area 5006 being the chest (S4A). In addition, since the detection areas A and B are arranged at positions separated from the side 5011 by a distance 5501 predetermined for imaging the chest in the first state, it is not necessary to adjust the positions of the detection areas A and B.

[0052] Also, it is assumed that the control unit 225 (control device 1002) has determined that the imaging target part 5006 is in the second state based on the rotation angle detected by the rotation detection unit 5003. In this case, the control unit 225 (control device 1002) selects, as the detection area, the detection areas B and E adjacent to the side 5011 that is the upper side of the imaging region 100 as seen from the subject 1011, according to the imaging target part 5006, that is, the chest (S4Ba). Also, in the second state, the detection areas B and E are arranged at a position separated by a distance 5502 from the side 5011, not at a position separated by a distance 5501 that is predetermined for imaging the chest. Therefore, the control unit 225 (control device 1002) adjusts the positions of the detection areas B and E so that they become the position 5010 separated by the distance 5501 from the side 5011, and sets the detection area (S4Bb).

[0053] The control unit 225 of the radiation imaging apparatus 1001 may enable detection of radiation in the detection area 5005 set as the detection area, and disable detection of radiation in the detection area 5005 not set as the detection area. For example, consider a case where detection areas A and B are set as the detection area. In this case, the control unit 225 of the radiation imaging apparatus 1001 may enable charge accumulation of the detection elements 121 in the detection areas A and B, and disable charge accumulation of the detection elements 121 in the other detection areas C to E. The control unit 225 of the radiation imaging apparatus 1001 may also control so that the driving circuit 241 does not drive the detection elements 121 in the detection areas C to E other than the detection areas A and B. The control unit 225 of the radiation imaging apparatus 1001 may also control so that the AD converter 146 of the readout circuit 242 does not digitally convert signals from the detection elements 121 in the detection areas C to E other than the detection areas A and B. In other words, the AD converter 146 may AD convert signals output from the detector elements 121 arranged in the detection area among the multiple detector elements 121 and supply the converted signals to the control unit 225, but may not AD convert signals output from the detector elements 121 not arranged in the detection area among the multiple detector elements 121. Furthermore, the control unit 225 of the radiation imaging device 1001 may control so that the signal processing unit 224 does not process signals from the detector elements 121 in detection areas C to E other than the detection areas A and B. In this way, by using various methods to disable detection of radiation in detection areas other than the detection area 5005 set as the detection area, the control unit 225 (control device 1002) can quickly calculate the reaching dose and request to stop exposure.

[0054] Next, in response to the user pressing the irradiation switch 1006, the control unit 225 (control device 1002) transmits an irradiation control signal (exposure request) to the radiation generating device 1004. In response to the irradiation control signal, the radiation generating device 1004 causes the radiation source 1003 to start irradiating radiation, and imaging begins (S5). During irradiation of radiation (imaging), the control unit 225 (control device 1002) acquires information on the dose of radiation incident on the detection area 5005 set as the detection region, and acquires an integrated value of the incident dose (S6).

[0055] During irradiation of radiation (during imaging), the control unit 225 (control device 1002) determines whether or not an integrated value of the radiation dose incident on the detection area 5005 set as the detection region exceeds a predetermined threshold (S7). When the integrated value of the radiation dose does not exceed the predetermined threshold, the control unit 225 (control device 1002) repeats the steps of S6 and S7. When the integrated value of the radiation dose exceeds the predetermined threshold, the control unit 225 (control device 1002) supplies an exposure stop request signal to the radiation generating device 1004 to stop irradiation of radiation. In response to the exposure stop request signal, the radiation generating device 1004 causes the radiation source 1003 to stop generating radiation. This ends imaging (S8). When there are a plurality of detection areas 5005 set as the detection region, the control unit 225 (control device 1002) may supply an exposure stop request signal when an integrated value of the radiation dose obtained by one of the plurality of detection areas 5005 exceeds a predetermined threshold. Furthermore, the control unit 225 (control device 1002) may supply an exposure stop request signal when an integrated value of the radiation dose obtained by all of the detection areas 5005 exceeds a predetermined threshold. For example, these conditions may be set when the user sets the imaging conditions.

[0056] Through the above processing, the radiation dose entering the detection area 5005 set as the detection region according to the imaging target part 5006 of the subject 1011 is monitored, and irradiation of radiation can be stopped at an appropriate timing. This makes it possible to prevent unnecessary irradiation of radiation to the subject 1011, and to obtain a radiographic image with good image quality due to an appropriate irradiation dose.

[0057] In the above example, the control unit 225 of the radiation imaging device 1001 sets the detection area in accordance with the part of the subject 1011 to be imaged and the rotation angle detected by the rotation detection unit 5003, but the present invention is not limited to this. For example, the control unit 225 causes signals to be output from all the detector elements 121 or all the set detection areas 5005. The control unit 225 or the control device 1002 may select an appropriate signal from these signals in accordance with the part of the subject 1011 to be imaged and the rotation angle detected by the rotation detection unit 5003, and monitor the irradiation of radiation.

[0058] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0059] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0060] 100: imaging region, 101: pixel, 225: control unit, 1001: radiation imaging device, 1011: subject, 5003: rotation detection unit

Claims

1. A radiation imaging device including: an imaging area in which a plurality of pixels are arranged to generate signals for acquiring a radiographic image in accordance with incident radiation; a control unit for setting a detection area which is an area used for detecting the radiation separately from acquiring the radiographic image in the imaging area; and a rotation detection unit, When the imaging region is disposed to face a subject, the rotation detection unit detects a rotation angle of a reference portion of the imaging region with respect to a reference orientation of the subject around an axis in a normal direction of the imaging region; the control unit determines, in accordance with the part of the subject to be imaged and the rotation angle, one of a plurality of sides defining the outer edge of the imaging area that is located in the same direction as the reference orientation of the subject, sets the detection area at a position a predetermined distance from the side for imaging the part of the subject to be imaged, and controls the imaging based on the dose of radiation incident on the detection area.

2. a plurality of detection areas for detecting incident radiation are set in advance in the imaging region; 2. The radiation imaging device according to claim 1, wherein the control unit selects a detection area to be used as the detection region from among the plurality of detection areas in accordance with the part to be imaged and the rotation angle, and adjusts a position of the selected detection area so that the position of the selected detection area is located at a predetermined distance from the side.

3. 3. The radiation imaging apparatus according to claim 2, wherein the control unit selects, from among the plurality of detection areas, a detection area that is closest to the side as the detection area to be used as the detection region.

4. 4. The radiation imaging apparatus according to claim 2, wherein each of the plurality of detection areas is rectangular.

5. 5. The radiation imaging apparatus according to claim 1, wherein the rotation detector detects the rotation angle by detecting an orientation of the reference portion with respect to a vertical direction.

6. 6. The radiation imaging apparatus according to claim 5, wherein the rotation detection unit includes an acceleration sensor.

7. 7. The radiation imaging apparatus according to claim 1, wherein the rotation detector detects the rotation angle by detecting a detection object fixed to a stand on which the radiation imaging apparatus is mounted.

8. The object to be detected includes a magnetic material, 8. The radiation imaging apparatus according to claim 7, wherein the rotation detection unit includes a magnetic sensor.

9. A plurality of detector elements for detecting incident radiation are arranged in the imaging region; 9. The radiation imaging apparatus according to claim 1, wherein the control unit detects the incident radiation using detector elements, among the plurality of detector elements, that are arranged in the detection region.

10. 10. The radiation imaging device according to claim 9, wherein the control unit causes a signal to be output from a detector element among the plurality of detector elements that is arranged in the detection region, and does not cause a signal to be output from a detector element among the plurality of detector elements that is not arranged in the detection region.

11. 10. The radiation imaging device according to claim 9, wherein the control unit controls imaging based on signals output from detector elements among the plurality of detector elements that are arranged in the detection region, and does not use signals output from detector elements among the plurality of detector elements that are not arranged in the detection region for controlling imaging.

12. Further comprising an AD converter for AD-converting a signal output from the imaging region, 12. The radiation imaging device according to claim 9, wherein the AD converter performs AD conversion on signals output from detector elements among the plurality of detector elements that are arranged in the detection region and supplies the converted signals to the control unit, and does not perform AD conversion on signals output from detector elements among the plurality of detector elements that are not arranged in the detection region.

13. 13. The radiation imaging apparatus according to claim 9, wherein some of the plurality of pixels function as any of the plurality of detector elements.

14. 13. The radiation imaging apparatus according to claim 9, wherein the plurality of detector elements are arranged separately from the plurality of pixels.

15. 15. The radiation imaging apparatus according to claim 1, wherein the reference direction is a direction toward a head of the subject.

16. 16. The radiation imaging apparatus according to claim 1, wherein the imaging target region is a chest region of the subject.

17. A radiation imaging apparatus according to any one of claims 1 to 16, a radiation generating device for irradiating the radiation imaging device with radiation; A radiation imaging system comprising: The control unit acquires an integrated value of the dose of radiation incident on the detection area, and supplies a signal to the radiation generating device to stop irradiating radiation when the integrated value exceeds a predetermined threshold.

18. A control device for controlling a radiation imaging device including an imaging region in which a plurality of pixels are arranged to generate a signal for acquiring a radiation image according to incident radiation, and a rotation detection unit, and a radiation generation device for irradiating the radiation imaging device with the radiation, the control device comprising: When the imaging region is disposed to face a subject, the rotation detection unit detects a rotation angle of a reference portion of the imaging region with respect to a reference orientation of the subject around an axis in a normal direction of the imaging region; The control device includes: controlling the radiation generating device based on a dose of the radiation detected in a detection region that is used for detecting the radiation separately from acquiring the radiation image in the imaging region; a control device which determines, among a plurality of sides defining the outer edge of the imaging area, a side which is located in the same direction as the reference orientation of the subject, in accordance with the part of the subject to be imaged and the rotation angle, and sets the detection area at a position spaced a predetermined distance from the side for imaging the part of the subject to be imaged.

19. A method for controlling a radiation imaging device including an imaging region in which a plurality of pixels are arranged to generate signals for acquiring a radiation image in accordance with incident radiation, and a rotation detection unit, comprising the steps of: positioning the imaging region facing a subject; causing the rotation detection unit to detect a rotation angle of a reference portion of the imaging region with respect to a reference orientation of the subject, around an axis in a normal direction of the imaging region; setting a detection region which is a region used for detecting the radiation separately from acquiring the radiation image in the imaging region; controlling imaging based on the dose of the radiation incident on the detection area; Including, a control method comprising: determining, among a plurality of sides defining the outer edge of the imaging area, a side located in the same direction as the reference orientation of the subject, in accordance with the part of the subject to be imaged and the rotation angle; and setting the detection area at a position a predetermined distance away from the side for imaging the part of the subject to be imaged.

20. A program for causing a computer to execute each step of the control method according to claim 19.

Images