Radiographic imaging apparatus and radiographic imaging system

Abstract

Disclosed are a radiation imaging apparatus and a radiation imaging system. Provided is a radiation imaging apparatus including: an imaging region in which a conversion element for obtaining an imaging operation of a radiation image corresponding to incident radiation is arranged; a detection section in which a detection element for detecting a radiation dose that enters the imaging region is arranged in each of the detection sections; and a controller. The controller is configured to: perform an offset readout operation of reading out an offset signal of the detection element from the detection section before the imaging operation; detect a radiation dose that enters the imaging region by using a signal output from the detection element during irradiation of radiation and the offset signal in the imaging operation; and be able to change an order of reading out the offset signal from the detection section during a period of the offset readout operation.

Description

Technical Field

[0001] This invention relates to radiation imaging apparatus and radiation imaging system. Background Technology

[0002] In medical imaging diagnostics and non-destructive examinations, radiographic imaging devices using FPDs (flat panel detectors) made of semiconductor materials are widely used. Such radiographic imaging devices are known to monitor radiation entering the device. By detecting the radiation dose in real time, the cumulative dose of radiation entering during radiation exposure can be determined, and AEC (automatic exposure control) can be performed. Japanese Patent Application Publication No. 2020-089714 describes a method for more accurately detecting radiation dose by pre-obtaining the offset of a detection pixel used for radiation dose detection, and correcting the signal output from the detection pixel during radiation exposure based on the pre-obtained offset. Summary of the Invention

[0003] To support multiple imaging processes, detection pixels for detecting radiation dose may be arranged in each of multiple regions, making it necessary to obtain the offset from the detection pixels arranged in each region. Furthermore, since the offset changes due to environmental variations such as the temperature of the radiation imaging apparatus, it is necessary to appropriately obtain the offset of the detection pixels in each region again and update the offset data. The offset of the detection pixels is obtained when radiation irradiation is not performed. In cases such as capturing radiation images at short intervals, depending on the update order of the offset data of the detection pixels in each region, radiation irradiation may begin before updating the offset data of the detection pixels used for AEC.

[0004] Each of the embodiments of the present invention provides a technique advantageous in improving the accuracy of AEC in radiographic imaging apparatus.

[0005] According to some embodiments, a radiation imaging apparatus is provided, comprising: an imaging region, wherein a plurality of conversion elements for an imaging operation to obtain a radiation image corresponding to incident radiation are arranged in the imaging region; a plurality of detection sections, wherein a detection element for detecting a radiation dose entering the imaging region is arranged in each of the plurality of detection sections; and a controller, wherein the controller is configured to perform an offset readout operation, prior to the imaging operation and in a state where no radiation irradiation has been performed, to read out an offset signal from the detection elements from the plurality of detection sections, wherein in the imaging operation, a radiation dose entering the imaging region is detected by using a signal output from the detection elements during radiation irradiation and the offset signal, and to be able to change the order in which the offset signal is read out from the plurality of detection sections during the period of the offset readout operation.

[0006] According to some other embodiments, a radiation imaging apparatus is provided, comprising: an imaging region, wherein a plurality of conversion elements for an imaging operation to obtain a radiation image corresponding to incident radiation are arranged in the imaging region; a plurality of detection portions, wherein a detection element for detecting a radiation dose entering the imaging region is arranged in each of the plurality of detection portions; and a controller, wherein the controller is configured to perform an offset readout operation to read out an offset signal of the detection element from the plurality of detection portions before the imaging operation, in a state in which no radiation irradiation is performed, and during the imaging operation, to detect a radiation dose entering the imaging region by using a signal output from the detection element during radiation irradiation and the offset signal, and the offset readout operation is performed in order according to the distance between the plurality of detection portions and the center of the imaging region.

[0007] Further features of the invention will become clear from the following description of exemplary embodiments (with reference to the accompanying drawings). Attached Figure Description

[0008] Figure 1 This is a flowchart illustrating the imaging operation process of a radiation imaging apparatus according to an embodiment;

[0009] Figure 2 This is a diagram illustrating an example configuration of a radiation imaging system using a radiation imaging apparatus according to an embodiment;

[0010] Figure 3 This is a diagram illustrating the arrangement of the imaging region of a radiation imaging apparatus according to an embodiment;

[0011] Figure 4 This is a diagram illustrating an example of the offset signal readout sequence of a radiation imaging apparatus according to an embodiment;

[0012] Figure 5 This is a diagram illustrating another example of the offset signal readout sequence of a radiation imaging apparatus according to an embodiment;

[0013] Figure 6 This is a diagram illustrating a case where the orientation of the imaging region relative to the vertical direction has been changed in a radiation imaging apparatus according to an embodiment;

[0014] Figure 7 This is a diagram illustrating yet another example of the offset signal readout sequence of a radiation imaging apparatus according to an embodiment;

[0015] Figure 8 This is a diagram illustrating an example of correcting a shift signal in a radiographic imaging apparatus according to an embodiment;

[0016] Figure 9 This is a flowchart illustrating an example of determining the offset signal readout order of a radiation imaging apparatus according to an embodiment;

[0017] Figure 10 This is a flowchart illustrating another example of determining the offset signal readout order of a radiation imaging apparatus according to an embodiment; and

[0018] Figure 11 This is a diagram illustrating yet another example of the offset signal readout sequence of a radiation imaging apparatus according to an embodiment. Detailed Implementation

[0019] In the following, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but the invention is not limited to requiring all such features, and multiple such features can be suitably combined. Furthermore, in the drawings, the same reference numerals are given the same or similar configuration, and repeated descriptions thereof are omitted.

[0020] The radiation in this invention may include alpha rays, beta rays, gamma rays, etc., which are beams produced by particles (including photons) emitted through radiation decay, as well as beams with similar or higher energies, such as X-rays, particle beams, cosmic rays, etc.

[0021] refer to Figures 1 to 11 The arrangement and operation of the radiographic imaging apparatus according to this embodiment will be described. Figure 1 This is a flowchart illustrating the imaging operation process of the radiation imaging apparatus 200 according to this embodiment. Figure 2 This is a diagram illustrating an example configuration of a radiographic imaging system SYS using the radiographic imaging apparatus 200 according to this embodiment. Before describing the imaging process using the radiographic imaging apparatus 200, the arrangement of the radiographic imaging apparatus 200 will be described. The radiographic imaging apparatus 200 can be used for, for example, medical purposes.

[0022] like Figure 2 As shown, the radiation imaging system SYS includes a radiation imaging device 200 and a radiation generating device 201 that irradiates the radiation imaging device 200 with radiation. The radiation generating device 201 irradiates the subject P with radiation. The radiation generating device 201 can be configured to include a radiation generator (bulb tube) for generating radiation, a collimator for defining the beam spread angle of the radiation generated by the radiation generator, and a radiation dose measuring instrument attached to the collimator.

[0023] like Figure 2As shown, the radiation imaging apparatus 200 may include an imaging unit 202, a setting unit 203, a controller 204, a processor 205, and a display unit 206. The imaging unit 202 includes an imaging region with multiple conversion elements arranged for an imaging operation to obtain a radiation image corresponding to incident radiation, and multiple detection sections, each of which has a detection element arranged for detecting the radiation dose entering the imaging region. The imaging unit 202 may be, for example, an FPD (flat panel detector) comprising multiple conversion elements in a two-dimensional distribution and generating radiation image data by detecting the two-dimensional distribution of radiation arriving at the imaging unit 202. The imaging unit 202 sends the radiation image data generated by the multiple conversion elements during the imaging operation to the processor 205. Furthermore, the imaging unit 202 sends information about the radiation dose detected by the detection sections to the controller 204.

[0024] Figure 3 This is a diagram illustrating an example arrangement of the imaging unit 202 of the radiation imaging apparatus 200 according to this embodiment. An imaging region 300 is arranged in the imaging unit 202, and a plurality of conversion elements 301 for acquiring a radiation image are arranged in the imaging region 300. The conversion elements 301 may also be referred to as pixels. Furthermore, a plurality of detection portions 302 are arranged in the imaging unit 202, and a detection element 312 for detecting the radiation dose entering the imaging region is arranged in each detection portion 302. The detection portions 302 may be as follows: Figure 2 The detector portion 302 is arranged next to the conversion element 301 in the imaging region 300, or it can be arranged at the outer edge of the imaging region 300, or it can be arranged outside the imaging region 300. In this embodiment, the detection portion 302 is arranged in each of five regions including region A, region B, region C, region D, and region E. Three rows of detection elements 312 are arranged in the detection portion 302 in each of regions A to E. The radiation dose entering the imaging region 300 is detected based on one or a combination of two or more of the plurality of detection portions 302. In this embodiment, the detection portions 302 are arranged in five regions A to E, and three rows of detection elements 312 are arranged in each detection portion 302. However, the invention is not limited thereto. For example, the detection portions 302 can be arranged in four or fewer regions, or they can be arranged in six or more regions. Furthermore, one detection element 312 can be arranged in each detection portion 302, or multiple detection elements 312 can be arranged in each detection portion 302. The arrangement can be appropriately changed according to the required specifications of the radiation imaging apparatus 200.

[0025] The setting unit 203 includes components used by an operator (e.g., a radiation technician) to input information such as the imaging site, target dose, irradiation conditions to be set in the radiation generating apparatus 201 to irradiate the radiation imaging apparatus 200, and imaging conditions specifying the imaging process. Irradiation conditions may include tube voltage (kV), tube current (mA), and conditions for collimators, filters, etc., to be set in the radiation generating apparatus 201. The setting unit 203 may include, for example, a keyboard or touch panel used by the operator to input imaging conditions. Figure 2 In the configuration shown, the radiation imaging apparatus 200 includes a setting unit 203, but the invention is not limited thereto. The setting unit 203 may be arranged outside the radiation imaging apparatus 200. If imaging conditions are input to the setting unit 203, the setting unit 203 sends the imaging condition information input by the operator to the controller 204.

[0026] The controller 204 controls the various components of the radiation imaging apparatus 200. Before an imaging operation begins by an operator requesting radiation irradiation by pressing an exposure switch, the controller 204 performs a offset readout operation to read the offset signals from the detection elements 312 from the multiple detection sections 302, in a state where no radiation irradiation has occurred. At this time, the offset signals can be read from the conversion element 301 arranged in the imaging region 300. Furthermore, during the imaging operation, the controller 204 detects the radiation dose entering the imaging region 300 using the signal output from the detection elements 312 during radiation irradiation and the offset signal obtained before the imaging operation. That is, the controller 204 performs correction processing on the signal obtained from the detection elements 312 arranged in the detection sections 302 during radiation irradiation using the offset signal obtained before the imaging operation. This processing improves the accuracy of radiation dose detection.

[0027] Processor 205 performs processing, such as grayscale processing or noise reduction processing, on the radiographic image data obtained during imaging operation from multiple conversion elements 301 arranged in the imaging region 300 of imaging unit 202. For example, processor 205 can perform correction processing on the radiographic image data using offset signals of the conversion elements 301 obtained before the imaging operation. Processor 205 sends the processed radiographic image data to display unit 206. Display unit 206 displays the radiographic image on a monitor or the like based on the data output from processor 205. Figure 2 In the configuration shown, the radiation imaging apparatus 200 includes a processor 205 and a display unit 206, but the invention is not limited thereto. The processor 205 and the display unit 206 may be arranged outside the radiation imaging apparatus 200.

[0028] Next, we will refer to Figure 1The imaging operation of the radiation imaging apparatus 200 according to this embodiment is described. When the radiation imaging apparatus 200 is powered on, in step S101, the controller 204 obtains the offset signals of the detection elements 312 from all five detection sections 302 arranged in the imaging unit 202. The controller 204 obtains and stores the offset signals of the detection elements 312 of the detection sections 302 in each of regions A to E. Figure 2 As shown, a memory 207 for storing the acquired offset signal data can be arranged in the radiographic imaging apparatus 200. The memory 207 can also be arranged in the controller 204. Once the storage of the offset signals output from the detection elements 312 of all detection sections 302 is complete, the controller 204 transitions from step S101 to step S102.

[0029] The period from step S102 to step S110 is the time period during which the offset readout operation is performed before the imaging operation, in a state where no radiation irradiation has been performed, to read out the offset signals of the detection elements 312 from the multiple detection sections 302. In step S102, the controller 204 determines the order in which the offset signals are read out from the multiple detection sections 302 (regions A to E). The controller 204 can control the imaging unit 202 to start reading out the offset signals in a predetermined order according to the start of the offset readout operation. For example, the controller 204 can read out the offset signals from the detection elements 312 of each detection section 302 in order of distance between the multiple detection sections 302 and the center of the imaging region 300. For example, as Figure 4 As shown, controller 204 can determine the order in which the offset signal is read out from the regions of the five detection portions 302 (regions A to E) arranged in imaging unit 202 that are closer to the center of imaging region 300. Alternatively, controller 204 can determine the order in which the offset signal is read out from the regions farther from the center of imaging region 300.

[0030] If the order in which the offset signals are obtained is determined in step S102, then the controller 204 proceeds to step S103 and controls the imaging unit 202 to obtain the offset signals in the determined order. Under the control of the controller 204, the imaging unit 202 causes the detection elements 312 of each detection section 302 to output offset signals in the order determined in step S102. The controller 204 stores the offset signal data read from the detection elements 312 of the detection section 302 in the memory 207. At this time, if there is offset signal data previously obtained from the detection elements 312 of the same detection section 302, then the controller 204 uses it to rewrite new offset signal data.

[0031] If the readout of the offset signal in step S103 begins, the process proceeds to step S104, and the controller 204 checks whether the operator has set the imaging conditions using the setting unit 203. In this embodiment, as described above, the imaging conditions may include the imaging site, the target dose of radiation to be applied to the subject P, the irradiation conditions to be set in the radiation generating device 201 (such as tube voltage kV and tube current mA), and information indicating the imaging process. If the operator inputs and sets the imaging conditions, the setting unit 203 sends the information of the imaging conditions set by the operator to the controller 204. If the imaging condition information is received, the controller 204 proceeds to step S105. If no imaging conditions are set, the process returns to step S103, and the controller 204 performs the process of obtaining the offset signal in the order determined in step S102. At this point, for example, if the determination in step S104 is executed when the offset signal is read from the detection element 312 of the detection section 302 in region B and the processing returns to step S103, then the controller 204 can restart the reading of the offset signal from the detection element 312 of the detection section 302 in region C. Alternatively, the controller 204 can execute the reading of the offset signal in step S103 and the determination in step S104 in parallel.

[0032] If imaging conditions are set in step S104 and the process moves to step S105, then controller 204 performs control to change the order of readout offset signals according to the set imaging conditions. First, in step S105, controller 204 refers to the imaging conditions set in step S104 and determines a new order for reading out offset signals from the plurality of detection portions 302 arranged in imaging unit 202.

[0033] For example, if the information indicating "lung imaging," used to specify the imaging process, is set as the imaging condition, then the controller 204 determines the order to read the offset signal from the detection portion 302 located above the imaging region 300. In this case, for example, it can be as follows: Figure 5 The offset signal is read out in the order of upper, center, and lower, as shown. Alternatively, for example, if information indicating "stomach imaging" is provided, then controller 204 determines the order to read the offset signal from the detection portion 302 located at the center of the imaging region 300, as shown. Figure 4 As shown in the image.

[0034] If the order in which the offset signals are obtained is determined in step S105, then the controller 204 proceeds to step S106 and controls the imaging unit 202 to obtain the offset signals in the determined order. Under the control of the controller 204, the imaging unit 202 causes the detection elements 312 of each detection section 302 to output offset signals in the order determined in step S105. The controller 204 stores the offset signal data read from the detection elements 312 of the detection section 302 in the memory 207. At this time, if there is offset signal data previously obtained from the detection elements 312 of the same detection section 302, then the controller 204 uses it to rewrite new offset signal data.

[0035] If the readout of the offset signal begins in step S106, the process proceeds to step S107, and the controller 204 checks whether the operator has specified a detection section 302 (areas A to E) among multiple detection sections 302 for radiation dose detection during the imaging operation using the setting unit 203. If a detection section 302 for radiation dose detection is specified, the setting unit 203 sends information about the detection section 302 specified by the operator to the controller 204. If information about the detection section 302 for radiation dose detection is received, the controller 204 proceeds to step S108. If no detection section 302 for radiation dose detection is specified, the process returns to step S106, and the controller 204 continues the process of obtaining the offset signal in the order determined in step S105. At this time, the controller 204 can restart the readout of the offset signal from the next detection section 302 in the order determined in step S105, which was the detection section 302 from which it read out the signal before the determination in step S107. Similar to the operations described above in steps S103 and S104, the controller 204 can execute steps S106 and S107 in parallel.

[0036] If a detection section 302 for detecting radiation dose is specified in step S107 and the process proceeds to step S108, then the controller 204 determines the order in which the offset signal is read from the specified detection section 302 among the plurality of detection sections 302. In this case, the controller 204 can determine the order so that the offset signal is obtained only from the detection section 302 specified by the operator among the plurality of detection sections 302. For example, if one detection section 302 is specified, then the controller 204 can determine that the offset signal is read continuously from one specified detection section 302. Alternatively, if two detection sections are specified, then the controller 204 can determine that the offset signal is read alternately from the two specified detection sections 302.

[0037] If the order in which the offset signals are obtained is determined in step S108, then the controller 204 proceeds to step S109 and controls the imaging unit 202 to obtain the offset signals in the determined order. Under the control of the controller 204, the imaging unit 202 causes the detection elements 312 of each detection section 302 to output offset signals in the order determined in step S108. The controller 204 stores the offset signal data read from the detection elements 312 of the detection section 302 in the memory 207. At this time, if there is offset signal data previously obtained from the detection elements 312 of the same detection section 302, then the controller 204 uses it to rewrite new offset signal data.

[0038] Steps S110 and S109 are executed in parallel. In step S110, the controller 204 determines whether the operator requests radiation exposure. More specifically, if an radiation request signal, generated by the operator pressing an exposure switch or the like, is input to the controller 204, then the process proceeds to step S111. If no radiation request signal is input, the controller 204 continues with the process of obtaining the offset signal in step S109.

[0039] If an irradiation request signal is input to the controller 204 in step S110 and processing proceeds to step S111, then the controller 204 sends an irradiation command signal to the radiation generating apparatus 201. Upon receiving the irradiation command signal, the radiation generating apparatus 201 begins irradiation according to the irradiation command signal. Furthermore, the controller 204 causes the conversion element 301 to begin the accumulation operation for acquiring a radiation image, and begins the readout of the signal from the detection element 312 of the detection section 302 specified in step S107 for detecting the incident radiation dose. Thus, imaging of the radiation image according to AEC (also known as AEC (Automatic Exposure Control) imaging) begins. The operations from steps S111 to S116 correspond to the time period of the imaging operation for acquiring a radiation image corresponding to the incident radiation.

[0040] In AEC imaging, under the control of controller 204, imaging unit 202 causes the detection element 312 of detection section 302, specified in step S107, to output a signal. Controller 204 performs offset correction on the signal read from detection element 312 based on offset signal data output from the detection element 312 of the same detection section 302 and stored in memory 207. Controller 204 successively adds up the offset-corrected signals. If the added signal reaches the target dose set in step S104, controller 204 sends an irradiation end signal to radiation generating device 201, and processing proceeds to step S112.

[0041] In step S112, if an irradiation end signal is received, the radiation generating device 201 stops irradiation, and AEC imaging terminates. Furthermore, the controller 204 terminates the operation of reading signals from the detection element 312 of the detection section 302. If AEC imaging terminates, the process proceeds to step S113.

[0042] In step S113, the controller 204 sends the radiation image data obtained by the various conversion elements 301 arranged in the imaging area 300 of the imaging unit 202 to the processor 205. Then, in step S114, the processor 205 performs correction processing, such as grayscale processing or noise reduction processing, on the radiation image data obtained by the conversion elements 301. The radiation image data that has undergone the correction processing of the processor 205 is sent to the display unit 206. If radiation image data is received, then in step S115, the display unit 206 converts the received radiation image data into a two-dimensional image and displays it to the operator. Then, in step S116, if an imaging end signal indicating that there is no further imaging is received, then the controller 204 terminates the process. Figure 1 The imaging sequence is shown. If no imaging end signal is received, the process returns to step S102.

[0043] exist Figure 1 The illustrated process depicts an example of the radiation imaging apparatus 200 performing correction processing and display of radiation image data, but the invention is not limited thereto. For example, in step S113, the controller 204 may output the radiation image data to the outside of the radiation imaging apparatus 200. In this case, processing such as correction and display of the acquired radiation image data can be performed by processing and display devices arranged outside the radiation imaging apparatus 200. In this case, the processing in steps S114 and S115 may not be performed.

[0044] As described above, the radiation imaging apparatus 200 according to this embodiment is configured to change the order in which offset signals are read from multiple detection sections 302 during the offset readout operation period performed before the imaging operation, depending on the imaging conditions in the imaging operation. Thus, for example, it becomes possible to update the offset signal data of the detection element 312 for detecting radiation dose while prioritizing the detection section 302 for AEC. Therefore, the possibility of radiation irradiation starting before updating the offset signal data of the detection element 312 for AEC can be suppressed. That is, the offset of the detection section 302, which may change due to environmental variations of the radiation imaging apparatus 200, can be corrected with high accuracy, making it possible to realize a radiation imaging apparatus 200 capable of performing AEC imaging with high accuracy.

[0045] In this embodiment, such as Figure 6 As shown, the radiation imaging apparatus 200 may further include a detector 601 that detects the orientation (rotation angle) of the imaging region 300 relative to the vertical direction. The detector 601 may be arranged in the imaging unit 202 on which the imaging region 300 is arranged. The controller 204 may change the order of reading off-signals according to the orientation detected by the detector. Figure 6 It shows Figure 3 The imaging region 300 shown is rotated 90° clockwise. By using the orientation of the imaging region 300 relative to the vertical direction detected by the detector 601, the controller 204 determines that the detection portion 302 in regions A and C is located at the upper part of the detection portion 302. For example, relative to... Figure 3 The arrangement of the various regions of the detection section 302 shown in the figure and Figure 4 The readout order shown is such that if the orientation of the imaging region 300 is as described... Figure 6 If the sequence is changed as shown, then controller 204 changes the order to follow the instructions. Figure 7 The offset signals are read out in the order shown.

[0046] If the imaging unit 202 is configured to simultaneously acquire offset signals from multiple detection portions 302, then the controller 204 can read out the offset signals in parallel from two or more of the multiple detection portions 302 in steps S103, S106, and S109. By reading out the offset signals in parallel from multiple detection portions 302, the interval between reading out the offset signals can be shortened. Therefore, newer offset signal data can be obtained during the period until the start of the imaging operation according to AEC imaging, enabling highly accurate AEC imaging to be achieved by correcting the offset of the detection portions 302 with high precision.

[0047] Furthermore, the incident radiation dose can be detected using a signal output from one detection element 312, or it can be detected using signals output from multiple detection elements 312. Detection elements 312 may include a first element and a second element having different sensitivities to each other, and the controller 204 can detect the radiation dose entering the imaging region 300 by using signals output from the first element and the second element.

[0048] Reference Figure 8 This describes a scenario where elements with different sensitivities are used to detect radiation dose. First, the controller 204 receives an offset signal O1 from a first element in the detection elements 312 and an offset signal O2 from a second element with lower sensitivity to radiation than the first element (steps S101, S106, and S109). Figure 8As shown, a dark component D1, generated independently of radiation irradiation, exists in the offset signal O1 of the first element. Furthermore, as... Figure 8 As shown, a dark component D2, generated independently of radiation, exists in the offset signal O2 of the second element. Here, it is assumed that the second element is, for example, completely shielded, and therefore has no sensitivity to radiation. The controller 204 stores the data of the offset signals O1 and O2 in the memory 207.

[0049] Then, if radiation irradiation begins in step S111, the controller 204 reads signals S1 and S2 from the first element and the second element respectively at predetermined intervals. Figure 8 As shown, the readout signal S1 of the first element contains a dark component D1 generated independently of radiation exposure, a crosstalk component CT generated between the first element and a nearby conversion element due to radiation exposure, and a radiation signal component R. Similarly, as Figure 8 As shown, the signal S2 of the second element contains a dark component D2 generated independently of radiation exposure, and a crosstalk component CT generated between the second element and a nearby conversion element due to radiation exposure. Since the second element is not sensitive to radiation, it does not include the radiation signal component R. The controller 204 performs offset correction on the signals S1 and S2 of the first and second elements during radiation exposure using data from the offset signals O1 and O2 of the first and second elements, respectively. Thus, the dark components D1 and D2 can be removed from the signals S1 and S2 of the first and second elements, respectively.

[0050] Therefore, the offset-corrected signal C1 of the first element includes the signal component R generated by radiation irradiation and the crosstalk component CT, and the offset-corrected signal C2 of the second element also includes the crosstalk component CT. The controller 204 subtracts the offset-corrected signal C2 of the second element from the offset-corrected signal C1 of the first element. This yields a signal SS from which the crosstalk component CT generated in the signal S1 output from the first element has been removed. The controller 204 successively adds up the signals SS. If the added signals SS reach the target dose set in step S104, the controller 204 sends a radiation irradiation end signal to the radiation generating device 201. Therefore, the effects of crosstalk generated between the conversion element and the detection element when detecting the incident radiation dose can be corrected, enabling a radiation imaging device 200 capable of performing AEC imaging with high accuracy.

[0051] If a radiation irradiation request signal is input when an offset signal is obtained in step S109 ("Yes" in step S110), then the controller 204 interrupts the processing of step S109. In this case, when the order of reading the offset signal is determined again in step S102, the controller 204 can determine the order so that the readout of the offset signal begins from the detection section 302 where the interruption occurred. For example, in an offset readout operation after an imaging operation of interest, the controller 204 can start the readout of the offset signal from the next detection section of the last readout of the multiple detection sections 302 in the offset readout operation performed before the imaging operation of interest, according to the order of the set imaging conditions (set in step S104).

[0052] Next, modifications to this embodiment will be described. In the radiation imaging apparatus 200, the frequency of use of the detection section 302 for AEC imaging may vary greatly among the detection sections 302, depending on conditions such as the location where the radiation irradiation apparatus 200 is installed. Therefore, the controller 204 may have the following function: for each detection section 302, store the frequency at which the detection section 302 is designated as the detection section 302 for detecting radiation dose during imaging operation in step S107. For example, the controller 204 may have a counter function and store the count value in the memory 207. The controller 204 may, for example, change the order of readout offset signals according to the designated frequency of the detection section 302 for detecting radiation dose in step S102. Alternatively, for example, the controller 204 may have the following function: for each detection section 302, store the designated frequency in step S107 in association with the imaging conditions set in step S104. In this case, if imaging conditions are set in step S104, the controller 204 can change the order of readout offset signals in step S105 according to the frequency associated with the set imaging conditions. This allows for high-precision correction of the effects of environmental variations in the installation location, where the frequency of use varies greatly between the detection sections 302, enabling the realization of a radiographic imaging apparatus 200 capable of performing AEC imaging with high accuracy.

[0053] For each of the five regions A to E, the controller 204 counts the information of the detection section 302 specified by the operator in step S107. Figure 9The operation in step S102 is illustrated, for example. In step S901, the controller 204 refers to information regarding the usage frequency of each of the five detection sections 302 arranged in the imaging unit 202 for radiation dose detection in AEC imaging. Then, in step S902, the controller 204 determines the order in which the offset signal is read from the detection section 302 with the highest frequency of radiation dose detection among the plurality of detection sections 302. Using this control, AEC imaging can be performed with high accuracy even if the frequency of radiation dose detection varies greatly among the detection sections 302.

[0054] Furthermore, if the controller 204 stores the specified frequency in step S107 for each detection section 302 in association with the imaging conditions set in step S104, then the processing in steps S901 and S902 can be performed in step S105. In this case, if the imaging conditions are set in step S104, the controller 204 refers to information regarding the usage frequency of each of the five detection sections 302 arranged in the imaging unit 202 for radiation dose detection under the imaging conditions set in step S104 (step S901). Then, the controller 204 determines the order in which the offset signal is read from the detection section 302 with the highest frequency for radiation dose detection (which is associated with the set imaging conditions) among the plurality of detection sections 302 (step S902). Thus, the offset signal can be read out in an order suitable for each imaging condition. As a result, highly accurate AEC imaging is achieved.

[0055] Furthermore, imaging conditions during the imaging operation may include information about the placement state of the radiographic imaging device 200 (imaging unit 202). Examples of information about the placement state of the radiographic imaging device 200 may include information about whether the radiographic imaging device 200 is placed in a fluoroscopy table. If the radiographic imaging device 200 is placed in a fluoroscopy table, then information about the posture of the fluoroscopy table, such as "supine" or "standing," may be included as imaging conditions. (Refer to...) Figure 10 Information describing imaging conditions includes the placement status of the radiation imaging device 200.

[0056] Figure 10 The diagram illustrates the process in step S105. In step S104, the operator sets the placement status information of the radiation imaging device 200 as imaging conditions. After the setting unit 203 sends the input placement status information of the radiation imaging device 200 to the controller 204, the process moves to step S105, and... Figure 10The process shown begins. In step S1001, the controller 204 refers to the received information on the placement status of the radiographic imaging device 200 to determine whether the radiographic imaging device 200 is placed in the fluoroscopy table. If the radiographic imaging device 200 is placed in the fluoroscopy table, the process proceeds to step S1002. If the radiographic imaging device 200 is not placed in the fluoroscopy table, the process proceeds to step S1005. In step S1002, the controller 204 refers to the posture of the fluoroscopy table included in the information on the placement status of the radiographic imaging device 200. If the posture of the fluoroscopy table is "supine," the process proceeds to step S1003. If the posture of the fluoroscopy table is "standing" ("No" in step S1002), the process proceeds to step S1004.

[0057] In step S1003, the controller 204 can determine the order in which the offset signals are read out based on the frequency of the detection section 302, which was specified in step S107 for detecting radiation dose. For example, if imaging conditions are set in step S104, the controller 204 can read out the offset signals in sequence from the detection section 302 having the highest frequency associated with the set imaging conditions.

[0058] In step S1004, the controller 204 determines the order in which the offset signal is read from the upper detection section among the plurality of detection sections 302, such as... Figure 5 As shown in the diagram. This is because if the fluoroscopy table is in a "standing position," then it is assumed that imaging of the lung fields is being performed.

[0059] If the radiographic imaging apparatus 200 is not placed in the fluoroscopy stage, imaging can be performed in various states. Therefore, in step S1005, the controller 204 determines to read the offset signal in the same order determined in step S102 as before setting the imaging conditions in step S104. For example, as described above, the order is determined so that the offset signal is read from the detection portion 302, which is closer to the center of the imaging region 300.

[0060] Using the processing described in steps S1001 to S1005, depending on the placement state of the radiation imaging device 200, it becomes possible to obtain offset signal data while prioritizing the detection section 302, which may be used for detecting radiation dose. Therefore, in various application locations where the radiation imaging device 200 is placed, the effects of environmental changes, etc., can be corrected with high accuracy, making it possible to realize a radiation imaging device 200 capable of performing AEC imaging with high accuracy.

[0061] Information regarding the placement status of the radiographic imaging device 200 is not limited to input by an operator using the setting unit 203. For example, the radiographic imaging device 200 may include sensors for determining whether it is placed in a fluoroscopy table. For instance, the sensors for determining whether the radiographic imaging device 200 is placed in a fluoroscopy table may be arranged in the portion of the radiographic imaging device 200 that will contact the fluoroscopy table. Furthermore, for example, connectors may be arranged to physically or electrically connect the radiographic imaging device 200 and the fluoroscopy table, and the placement of the radiographic imaging device 200 in the fluoroscopy table can be determined based on the connection status of the connectors. Additionally, the radiographic imaging device 200 may use, for example... Figure 6 The detector 601 shown is used to detect the posture of the viewing table.

[0062] The controller 204 can cyclically change the order of readout from the detection elements 312 of the detection section 302. Therefore, even when imaging operations are repeated at short intervals, it becomes easy to readout the offset signals from the detection elements 312 of the detection sections 302 arranged in different areas during the imaging operation. Thus, the effects of environmental changes, etc., can be corrected with high accuracy in all detection sections 302, enabling the realization of a radiation imaging apparatus 200 capable of performing AEC imaging with high accuracy.

[0063] Figure 11 This is a diagram illustrating an example of cyclically changing the order of the readout offset signals. In step S103, the controller 204 first follows... Figure 11 The sequence I shown executes the operation of reading the offset signal from the detection section 302. Then, after reading the offset signal from each of the plurality of detection sections 302, the controller 204 proceeds according to... Figure 11 The sequence I+1 shown executes the operation of reading the offset signal from the detection section 302. Furthermore, after reading the offset signal from each of the plurality of detection sections 302 in sequence I+1, the controller 204... Figure 11 The sequence I+2 shown executes the operation of reading the offset signal from the detection section 302. Subsequently, the operation of reading the offset signal from the detection section 302 is executed in sequence I+3 and sequence I+4, and then the operation of reading the offset signal from the detection section 302 is executed again in sequence I.

[0064] In this way, the order of regions A, B, C, D, and E for reading the offset signal, determined in step S102, remains unchanged, but the order changes cyclically each time an offset signal is read from each of the plurality of detection sections 302. In this case, as... Figure 11As shown, the priority of the detection section 302, which gives the highest priority to reading the offset signal in sequence I, can be changed to the lowest priority in sequence I+1. More specifically, assume a first operation of reading the offset signal from each of the plurality of detection sections 302 and a second operation of reading the offset signal from each of the plurality of detection sections 302 after the first operation. In this case, in the second operation, the order of reading the offset signal is changed such that, among the plurality of detection sections 302, the offset signal is finally read from the detection section that first read the offset signal in the first operation. Thus, even in a short period of time, the offset signal can be easily read from all detection sections 302.

[0065] The moment of transition from sequence I to sequence I+1 can be the moment when the offset signal is read once from each of the multiple detection sections 302, or it can be the moment when the offset signal is read two or more times from each of the multiple detection sections 302. The order of reading the offset signal can be changed cyclically not only in step S103, but also in the processes of steps S106 and S109.

[0066] By cyclically changing the order of readout of the offset signals, for example, even in the case of repeated imaging in which a radiation irradiation request signal is input during the acquisition of offset signal data, it becomes easy to readout the offset signals from all detection sections 302. As a result, the effects of environmental changes, etc., are suppressed, making it possible to realize a radiation imaging apparatus 200 capable of performing AEC imaging with high accuracy.

[0067] The radiation imaging apparatus 200 may also include a method specifying unit for an operator to specify the various methods described above for the controller 204 to change the order of the readout offset signals. For example, the setting unit 203 may have the function of a method specifying unit for an operator to select a method for changing the order of the readout offset signals. The controller 204 changes the order of the readout offset signals as described above according to the method input in the method specifying unit.

[0068] Other embodiments

[0069] Embodiments of the present invention can also be implemented by a computer of a system or apparatus that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a 'non-transitory computer-readable storage medium') to perform one or more functions of the above embodiments and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing one or more functions of the above embodiments, and by a method performed by the computer of the system or apparatus by, for example, reading and executing computer-executable instructions from the storage medium to perform one or more functions of the above embodiments and / or controlling one or more circuits to perform one or more functions of the above embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include separate computers or networks of separate processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or storage medium. The storage medium may include, for example, a hard disk, random access memory (RAM), read-only memory (ROM), storage devices for distributed computing systems, optical discs (such as CDs, DVDs, or Blu-ray discs). TM One or more of the following: flash memory devices, memory cards, etc.

[0070] The embodiments of the present invention can also be implemented by providing software (programs) that perform the functions of the above embodiments to a system or device via a network or various storage media, and the computer or central processing unit (CPU) or microprocessor unit (MPU) of the system or device reads out and executes the program.

[0071] While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be given the broadest interpretation in order to cover all such modifications and equivalent structures and functions.

Claims

1. A radiation imaging device, comprising: An imaging region, wherein multiple conversion elements for an imaging operation to obtain an imaging image corresponding to the incident radiation are arranged in the imaging region. Multiple detection sections, each of which is arranged with a detection element for detecting the radiation dose entering the imaging region; as well as Controller The controller is configured to Prior to the imaging operation, an offset readout operation is performed to read out the offset signals of the detection elements from the plurality of detection sections without radiation exposure. In the imaging operation, the radiation dose entering the imaging region is detected using the signal output from the detection element during radiation irradiation and the offset signal. The order in which the offset signals are read from the plurality of detection sections can be changed during the offset readout operation period. The controller has the function of storing the frequency of the detection section among the plurality of detection sections designated for detecting radiation dose in the imaging operation, and The controller changes the order in which the offset signal is read according to the frequency.

2. The apparatus according to claim 1, wherein The controller is configured to change the order in which the offset signals are read from the plurality of detection portions during the offset readout operation, depending on the imaging conditions in the imaging operation.

3. The apparatus according to claim 2, wherein The controller begins reading the offset signal in a predetermined order upon the start of the offset readout operation, and changes the order of reading the offset signal according to the set imaging conditions if the imaging conditions are set.

4. The apparatus according to claim 3, wherein After the imaging conditions are set, if a detection section for detecting radiation dose during the imaging operation is specified among the plurality of detection sections, then the controller reads the offset signal from the specified detection section among the plurality of detection sections.

5. The apparatus according to claim 1, wherein The controller reads the offset signal sequentially from the detection section with the highest frequency among the plurality of detection sections.

6. The apparatus according to claim 3, wherein The imaging operation includes a first imaging operation and a second imaging operation, wherein the second imaging operation is performed after the first imaging operation. The offset readout operation includes a first offset readout operation and a second offset readout operation. The first offset readout operation is performed before the first imaging operation, and the second offset readout operation is performed between the first imaging operation and the second imaging operation. In the second offset readout operation, the controller starts reading out the offset signal from the next detection part of the last detection part read out in the plurality of detection parts in the first offset readout operation, according to the order of the set imaging conditions.

7. The apparatus according to claim 3, wherein The predetermined order is determined based on the distance between the plurality of detection portions and the center of the imaging region.

8. The apparatus according to claim 1, further comprising: A detector configured to detect the orientation of the imaging region relative to a vertical direction. The controller changes the order in which the offset signal is read according to the orientation.

9. The apparatus according to claim 2, wherein The imaging conditions include at least one of the following: imaging site, target dose, irradiation conditions to be set in the radiation generating device to irradiate the radiation imaging device with radiation, and information indicating the imaging process.

10. The apparatus according to claim 2, wherein The imaging conditions include information about whether the radiographic imaging device is placed in a fluoroscopic stage.

11. The apparatus of claim 10, wherein If the device is placed in a fluoroscopic stage, the imaging conditions also include information about the orientation of the fluoroscopic stage.

12. The apparatus according to claim 2, wherein The imaging conditions include information about whether the device is placed in a fluoroscopy stage, and If the device is not placed in the fluoroscopy stage, the controller reads the offset signal in the same order as before the imaging conditions were set. If the device is placed in a fluoroscopy table and the table is in a supine position, then the offset signal is read out according to the frequency, and If the device is placed in a fluoroscopy stage and the fluoroscopy stage is in a "standing position", then the offset signal is read out sequentially from the upper detection section among the plurality of detection sections.

13. The apparatus according to claim 1, wherein The offset readout operation includes a first operation of reading the offset signal from each of the plurality of detection portions, and a second operation of reading the offset signal from each of the plurality of detection portions after the first operation. The controller cyclically changes the order in which the offset signal is read between the first operation and the second operation.

14. The apparatus of claim 13, wherein The controller changes the order in which the offset signal is read out, so that in the second operation, the offset signal is finally read out from the detection portion that was read out first in the first operation.

15. The apparatus according to claim 1, wherein The controller further includes a method specifying unit, which is used to specify a method for changing the order in which the offset signals are read out, and The controller changes the order in which the offset signals are read according to the method input in the method-specified unit.

16. The apparatus according to claim 1, wherein The detection element includes a first element and a second element, the first element and the second element having different sensitivities to each other, and The controller detects the radiation dose entering the imaging region by using signals output from the first element and the second element.

17. The apparatus according to claim 1, wherein The controller reads the offset signal in parallel from no less than two of the plurality of detection sections.

18. A radiation imaging system, comprising: The radiation imaging apparatus according to any one of claims 1 to 17; as well as A radiation generating device configured to irradiate the radiation imaging device with radiation.

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