Radiation imaging apparatus, radiation imaging method, program product, and storage medium

Abstract

The invention relates to a radiation imaging apparatus, a radiation imaging method, a program product, and a storage medium. A radiation imaging apparatus includes a plurality of reception fields in which radiation doses can be detected during radiation imaging in which a radiation irradiation apparatus emits radiation. The radiation imaging apparatus is capable of performing a process for stopping irradiation based on a dose detection result in at least one of the plurality of reception fields. The radiation imaging apparatus includes one or more controllers configured to adjust a parameter associated with a reception field for dose detection based on registration error information of an object at the time of radiation imaging.

Description

Technical Field

[0001] The disclosed technology relates to a radiation imaging apparatus, a radiation imaging method, a program product, and a storage medium. Background Art

[0002] As an imaging apparatus for medical imaging diagnosis or non-destructive inspection using X-rays, a radiation imaging apparatus composed of a conversion element that converts radiation into charge, a switching element such as a thin film transistor, a pixel array provided with wiring, a drive circuit, and a readout circuit is currently in practical use.

[0003] One of the radiation imaging apparatuses has a function of detecting irradiation information while a radiation source emits radiation. This function includes a function of detecting the incident start timing of the radiation emitted by the radiation source and a function of detecting the dose and integrated dose of the radiation. Using this function, automatic exposure control can be performed, in which the integrated dose is monitored, and when the integrated dose reaches an appropriate amount, the detection apparatus controls the radiation source to end irradiation.

[0004] Japanese Patent Laid-Open No. 2021-79023 discloses a technique for performing imaging of a site to be captured with an appropriate dose by controlling the irradiation of radiation based on information associated with a region of interest when using automatic exposure control.

[0005] However, in the technique disclosed in Japanese Patent Laid-Open No. 2021-79023, since the detection region for detecting the integrated dose is located at a fixed position, it is necessary to pre-select the detection region according to the imaging site of the subject. In this case, if the pre-selected detection region deviates from the position of the subject, or if there are differences in body thickness due to differences in age / gender, etc., the exposure cannot be appropriately controlled, and thus the dose of the radiation may change.

[0006] The disclosed technology provides a radiation imaging technique capable of suppressing changes in radiation dose. Summary of the Invention

[0007] According to one aspect of the present invention, there is provided a radiation imaging apparatus including a plurality of receptor fields capable of detecting a radiation dose during radiation imaging in which a radiation irradiation apparatus emits radiation, and the radiation imaging apparatus being capable of performing a process for stopping irradiation based on a dose detection result in at least one of the plurality of receptor fields, the radiation imaging apparatus including: one or more controllers configured to adjust parameters associated with a receptor field for dose detection based on registration error information of a subject during radiation imaging.

[0008] According to another aspect of the present invention, there is provided a radiation imaging method for a radiation imaging apparatus, the radiation imaging apparatus including a plurality of reception fields capable of detecting a radiation dose therein during radiation imaging in which a radiation irradiating apparatus emits radiation, and the radiation imaging apparatus being capable of performing a process for stopping irradiation based on a dose detection result in at least one of the plurality of reception fields, the radiation imaging method including: adjusting a parameter associated with a reception field for dose detection based on registration error information of an object during radiation imaging.

[0009] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram showing the configuration of a radiation imaging system according to a first embodiment;

[0011] Figure 2 is a block diagram showing the arrangement of an FPD processing unit according to a first embodiment;

[0012] Figure 3 is a diagram indicating an example of a change in automatic exposure control in the case where the position of an object is deviated in the vertical direction with respect to a radiation imaging apparatus according to a first embodiment;

[0013] Figure 4A and Figure 4B is a diagram showing an example of weighting based on output information in the case where the position of an object is deviated upward with respect to a radiation imaging apparatus according to a first embodiment;

[0014] Figure 5 is a diagram indicating an example of weighting based on an output ratio in the case where the position of an object is deviated to the right according to a first embodiment;

[0015] Figure 6 is a diagram and a graph indicating an example of weighting based on output information in the case where the size of an object is small according to a second embodiment;

[0016] Figure 7 is a graph indicating examples of curves each showing a histogram in the case where a registration error occurs in the position of an object 105 with respect to an FPD 102;

[0017] Figure 8 is a diagram showing the configuration of a radiation imaging system according to a second embodiment;

[0018] Figure 9 is a diagram exemplifying a table storing imaging condition information, reference output information, and reference weighting information;

[0019] Figure 10 is a diagram illustrating a table storing reference body grid information, reference output information, and reference weighting information; and

[0020] Figure 11 is a diagram showing the configuration of a radiation imaging system according to a third embodiment. Detailed Description of the Invention

[0021] Embodiments will be described in detail below 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 of these features, and multiple such features can be combined as appropriate. In addition, in the drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions thereof are omitted.

[0022] Note that each of the embodiments to be described below will illustrate a case where the disclosed technology is applied to an X-ray imaging device as a radiation imaging device, and the X-ray imaging device uses X-rays as a type of radiation to capture X-ray image data of an object. In addition, the disclosed technology is not limited to X-ray imaging devices, and can be applied to radiation imaging devices that use other types of radiation (e.g., α-rays, β-rays, and γ-rays) to capture radiation images of an object.

[0023] Automatic exposure control (AEC) will be mainly described, but the disclosed technology can also be used for radiation dose measurement (monitoring) used for AEC, and the imaging device itself does not need to perform radiation control. In addition, the disclosed technology can also be used to detect the start of radiation irradiation, and can also be used to detect the end of radiation irradiation.

[0024] (First Embodiment)

[0025] Figure 1 is a diagram showing an example of the configuration of a radiation imaging system 100 including a radiation imaging device according to the first embodiment. The radiation imaging system 100 is used, for example, when capturing radiation images in a hospital, and includes a radiation imaging device 102 and an imaging control device 103 as system configurations. The radiation imaging device 102 captures a radiation image based on radiation emitted from a radiation source 101. The imaging control device 103 is connected to the radiation imaging device 102 and a radiation control device 104 that controls the radiation source 101 through, for example, a wired or wireless network or a dedicated line, and controls radiation imaging using the radiation imaging device 102 and the radiation source 101.

[0026] (Radiation Source 101)

[0027] Refer to Figure 1, the radiation source 101 holds, for example, a rotor and an X-ray tube. The X-ray tube accelerates electrons by high voltage and collides with the anode to generate radiation. The radiation source 101 irradiates the object 105 with X-rays.

[0028] (Radiation imaging device 102)

[0029] The radiation imaging device 102 is a flat panel detector (hereinafter referred to as FPD) in which a plurality of pixels are arranged in a matrix on a flat substrate, and includes an image sensor with a two-dimensional distribution. The FPD 102 detects the two-dimensional distribution (dose information) of the radiation dose that has passed through the object 105 and reached the image sensor, thereby generating image data. The FPD 102 transmits the generated image data (radiation image data) to the image processing unit 1034 of the imaging control device 103. In addition, the FPD 102 transmits the dose information of the two-dimensional distribution of the detected radiation dose and the determination information for controlling the irradiation of the radiation in the automatic exposure control to the imaging control device 103.

[0030] In the FPD 102, detection pixels are arranged, and each detection pixel includes a radiation detection element for monitoring the radiation dose. The detection pixels are distributed and arranged in the FPD 102. The detection area 1021 is arranged in the FPD 102 and includes a plurality of image data generation pixels and a plurality of detection pixels. The radiation dose is monitored for each detection area, and a representative value is used as the pixel information of the detection pixels in each detection area. As the pixel information (representative value) of the detection pixels in each detection area, the average value of the signals of the detection pixels will be taken as an example in the following embodiments. However, the present invention is not limited thereto. The pixel information (representative value) of the detection pixels can be, for example, the median, mode, integral value, etc. based on the arithmetic processing of the signals detected by a plurality of detection pixels.

[0031] In addition, in the description of each embodiment in the following embodiments, the detection area will be illustrated by examples of five areas or nine areas, but is not limited to these examples. In the automatic exposure control (AEC) according to the disclosed technology, arithmetic processing is performed on the signal values (monitoring signal values) obtained from the detection pixels in the selected detection area, and thus the position and size of the detection area, the number of selected detection areas, etc. have no influence.

[0032] (Imaging control device 103)

[0033] The imaging control device 103 relays the communication between the FPD 102 and the radiation control device 104. The communication method in the imaging control device 103 can be a wired communication method or a wireless communication method. The imaging control device 103 includes an imaging condition setting unit 1031, an imaging control unit 1032, a processing unit 1033, an image processing unit 1034, a display control unit 1035, a storage unit 1036, and a communication IF unit 1037. The communication IF unit 1037 serves as a communication interface for transmitting data to / from the FPD 102 or the radiation control device 104 and receiving data from the FPD 102 or the radiation control device 104.

[0034] The storage unit 1036 can be formed by, for example, a storage medium including storage devices such as a hard disk drive (HDD), a solid state drive (SSD), or an optical disk drive. The storage unit 1036 can store various information and data obtained from each unit component, information about the object, image data obtained by capturing the object in the past, various computer programs for executing the processing of the imaging control device 103, and a table of reference weighting information set for each detection area.

[0035] Figure 9 It is a diagram illustrating a table storing imaging condition information, reference output information, and reference weighting information. In the table of reference weighting information, a reference value (reference output information) of the output signal in each detection area and reference weighting information in each detection area are set for each piece of imaging condition information. Referring to the table in the storage unit 1036, the reference value (reference output information) of the output signal in each detection area and the reference weighting information in each detection area set for each piece of imaging condition information can be obtained as initial values. The reference output information includes the output signals output from multiple detection areas when there is no registration error of the object with respect to the multiple detection areas. The reference weighting information includes the reference value of the weighting information when there is no registration error of the object with respect to the multiple detection areas.

[0036] Each unit component of the imaging control device 103 can operate according to a computer program. For example, the functions of each unit component can be realized by loading a computer program stored in the storage unit 1036 etc. and executing the computer program by the processing unit 1033. Alternatively, some or all of the functions of the unit components of the imaging control device 103 can be realized by using a dedicated circuit. The communication delay and processing delay between the units in the imaging control device 103 are managed according to the communication method, communication content, and processing content. Therefore, each unit in the imaging control device 103 can perform communication by predicting the communication delay and processing delay.

[0037] Next, the functional components of the imaging control device 103 will be described.

[0038] (Imaging condition setting unit 1031)

[0039] The imaging condition setting unit 1031 receives the imaging condition information input by the operator via the operation input unit 108, and transmits the received imaging condition information to the imaging control unit 1032 and the processing unit 1033. For example, the imaging condition information regarding the object to be imaged includes: object information including age, gender, and physique, the imaging part of the object, tube voltage, tube current, irradiation time, and threshold information for controlling the signal output to the radiation source 101 to stop the radiation source 101 under a predetermined dose. In addition, the imaging condition information includes reference output information for each detection area for controlling radiation irradiation, and reference weighting information. The imaging condition information input by the operator can be stored in the storage unit 1036.

[0040] (Processing unit 1033)

[0041] The processing unit 1033 transmits the dose information transmitted from the FPD 102 and the determination information for controlling the irradiation of radiation in the automatic exposure control to the imaging control unit 1032. "Dose information" generally represents the dose of the radiation emitted from the radiation source 101 that has reached the FPD 102, but dose information similar thereto can also be used.

[0042] The processing unit 1033 includes a reference weighting unit 1038 as a functional component. The reference weighting unit 1038 sets reference output information and reference weighting information for the detection areas in the FPD 102 based on the imaging condition information set by the imaging condition setting unit 1031. When there are multiple detection areas in the pixel area of the FPD 102, the reference weighting unit 1038 sets reference output information and reference weighting information for each detection area.

[0043] When the imaging condition information for imaging the object 105 is input from the imaging condition setting unit 1031, the reference weighting unit 1038 refers to the table in the storage unit 1036 to specify the imaging condition information corresponding to the input imaging condition information. The reference weighting unit 1038 obtains the reference value (reference output information) of the output signal in each detection area and the reference weighting information in each detection area as initial values based on the specified imaging condition information, and transmits them to the FPD 102 via the communication IF unit 1037.

[0044] The FPD 102 includes an FPD processing unit 200 that processes the output signal output from the detection area ( Figure 2) and the weighting unit 202 in the FPD processing unit 200 sets the reference value (reference output information) of the output signal transmitted from the reference weighting unit 1038 as the reference value to be compared with the output signal (monitoring signal value) that is output from each detection area in real time through the imaging by the FPD 102.

[0045] The weighting unit 202 sets the reference weighting information transmitted from the reference weighting unit 1038 as the initial value of the weighting information for each detection area. Based on the comparison between the output signal (monitoring signal value) output from each detection area in real time and the reference value (reference output information) of the output signal, the weighting unit 202 changes the reference weighting information set as the initial value. The actual processing of the weighting unit 202 will be described in detail later.

[0046] (Imaging control unit 1032)

[0047] The imaging control unit 1032 controls the radiation control device 104 and the FPD 102 based on the imaging condition information received from the imaging condition setting unit 1031 and the information received from the processing unit 1033.

[0048] (Image processing unit 1034)

[0049] The image processing unit 1034 performs processing such as dark current correction, gain correction, defect correction, tone processing, and noise reduction processing on the radiation image data transmitted from the FPD 102. The image processing unit 1034 transmits the radiation image data that has undergone image processing to the display control unit 1035.

[0050] (Display control unit 1035)

[0051] The display control unit 1035 performs display control to display the image information transmitted from the image processing unit 1034 on a display unit 106 such as a monitor. For example, the display unit 106 is formed of any device such as a liquid crystal display (LCD), a cathode ray tube (CRT) display, a plasma display panel, or an organic EL panel, and displays the radiation image data that has undergone image processing obtained from the image processing unit 1034.

[0052] (Explanation of AEC operation)

[0053] Next, it will be described with reference to Figure 1Schematically describe the AEC operation when imaging an object. Before imaging the object, imaging condition information is set in the imaging condition setting unit 1031 regarding the object to be imaged. The imaging condition information includes: object information including age, gender, and physique, the imaging part of the object, tube voltage, tube current, irradiation time, and threshold information for controlling the signal output to the radiation source 101 to stop the radiation source 101 under a predetermined dose. At this time, reference weighting information and reference output information for controlling the detection area of radiation irradiation can be input. The input imaging condition information can be sent to the imaging control unit 1032 and the processing unit 1033 and stored in a table in the storage unit 1036.

[0054] When the radiation switch 107 installed on the radiation control device 104 is pressed, the radiation control device 104 controls the radiation source 101 to start irradiating radiation. After the radiation source 101 starts irradiation, when the cumulative dose of radiation reaches the predetermined dose, the FPD 102 transmits determination information (irradiation stop signal) to the imaging control device 103, and the imaging control device 103 transmits the irradiation stop signal to the radiation control device 104. Upon receiving the irradiation stop signal, the radiation control device 104 controls the radiation source 101 to stop irradiating radiation from the radiation source 101.

[0055] At this time, the predetermined dose is a value calculated considering the dose set before imaging the object, the change in X-ray irradiation intensity, and the communication delay and processing delay between units. If the irradiation time set before imaging the object is reached, the radiation control device 104 stops irradiating radiation from the radiation source 101 regardless of the presence or absence of the irradiation stop signal.

[0056] (Functional components of the FPD processing unit 200)

[0057] Next, refer to Figure 2 Describe the functional components associated with the automatic exposure control (AEC) of the radiation imaging device 102 (FPD). The FPD processing unit 200 of the radiation imaging device 102 is provided in a pixel area in which a plurality of pixels each for detecting radiation are arranged, and processes output signals output from a plurality of detection areas, each detection area including detection pixels each for outputting a signal corresponding to the radiation dose. The FPD processing unit 200 includes a signal combination unit 201, a weighting unit 202, a determination information setting unit 203, a threshold determination unit 204, and a communication IF unit 205 as functional components. The communication IF unit 205 serves as a communication interface for transmitting data to / receiving data from the imaging control device 103.

[0058] (Signal combination unit 201)

[0059] The signal combining unit 201 receives output signals (hereinafter referred to as monitoring signal values) output from each detection area (e.g., the detection area 1021 in Figure 1 etc.), and outputs a monitoring signal value (hereinafter referred to as a combined monitoring signal value) obtained by performing signal combining processing on the received monitoring signal values. The monitoring signal value (combined monitoring signal value) can be, for example, the average value of the detection pixel signal values included in each area or the average value of a predetermined number of detection pixel signal values selected from among a plurality of detection pixels included in the detection area.

[0060] (Weighting unit 202)

[0061] The weighting unit 202 sets the reference value (reference output information) of the output signal transmitted from the reference weighting unit 1038 of the imaging control device 103 as the reference value to be compared with the output signal (monitoring signal value) that is output in real time from each detection area through imaging by the FPD 102. In addition, the weighting unit 202 sets the reference weighting information transmitted from the reference weighting unit 1038 as the initial value of the weighting information for each detection area.

[0062] The weighting unit 202 generates weighting information for each detection area by comparing the output signal (monitoring signal value) that is output in real time from each detection area during imaging with the reference value of the output signal (reference output information), and changes the reference weighting information set as the initial value.

[0063] The weighting unit 202 generates dose information based on the weighting information for each detection area and the monitoring signal value (combined monitoring signal value) output from the signal combining unit 201. As detailed processing, the weighting unit 202 generates dose information (weighted monitoring signal value) by multiplying the monitoring signal value (combined monitoring signal value) by the weighting information for each detection area.

[0064] The weighting unit 202 can acquire output information (reference output information) and reference weighting information from the imaging control device 103 via the communication IF unit 205, or can save or generate reference output information and reference weighting information to generate weighting information for each detection area. For example, a plurality of output information (reference output information) as references can be saved or generated in association with the imaging site, subject information including build and age, and imaging condition information including tube voltage and grid.

[0065] As output information (reference output information), for example, the position of the object relative to the FPD 102 (multiple detection regions) can be set as a reference, or the ratio between the output information (reference output information) in the multiple detection regions can be set as a reference. Alternatively, information (reference physique information) set based on the physique of the object (e.g., the width, thickness, etc. of an adult or child's body) can be used as a reference. The weighting unit 202 can select a predetermined number of detection pixels from the multiple detection pixels in the detection region as representative pixels, and perform a weighting operation on the monitoring signal values from the selected representative detection pixels. In this case, compared with weighting all the detection pixels in the detection region, the arithmetic processing load can be reduced. In addition, the weighting unit 202 can also select the detection pixels at the necessary positions from the selected detection pixels.

[0066] (Determination information setting unit 203)

[0067] The determination information setting unit 203 sets a threshold for the dose information representing the representative value of each detection region. Note that as the threshold set by the determination information setting unit 203, the information included in the imaging condition information set by the imaging condition setting unit 1031 of the imaging control device 103 can be used, and this information is obtained via the communication IF unit 205. The set threshold is information for determining whether the dose of the emitted radiation has reached the cumulative dose in the AEC operation.

[0068] (Threshold determination unit 204)

[0069] The weighting unit 202 of the FPD processing unit 200 generates weighting information for each of the multiple detection regions by comparing the output signal with preset reference information, and the threshold determination unit 204 generates determination information for controlling the irradiation of the radiation by comparing the dose information obtained by weighting the output signal based on the generated weighting information with a preset threshold. By comparing the dose information (weighted monitoring signal value) generated by the weighting unit 202 with the threshold set by the determination information setting unit 203, the threshold determination unit 204 determines whether the dose from the radiation source 101 has reached a predetermined cumulative dose. Then, based on the determination result, the threshold determination unit 204 generates determination information for controlling the irradiation of the radiation. The determination information is information (irradiation control information) for controlling the irradiation of the radiation (continuing irradiation or stopping irradiation) in the AEC. The determination information generated by the threshold determination unit 204 is transmitted to the imaging control device 103 via the communication IF unit 205.

[0070] If the dose information (monitoring signal value × weighting information) is lower than the threshold before reaching the preset irradiation time before imaging the object, it is determined that the information is information indicating continuous irradiation of radiation (irradiation continuation signal), and if the dose information is equal to or higher than the threshold, it is determined that the information is information indicating stopping the irradiation of radiation (irradiation stop signal). Note that if the preset irradiation time before imaging the object is reached, the radiation control device 104 stops the irradiation of radiation from the radiation source 101 regardless of the presence or absence of the irradiation stop signal.

[0071] The threshold determination unit 204 can determine whether the dose has reached a predetermined cumulative dose by comparing the dose information with the threshold based on a determination method (AND condition, OR condition, AVG condition, etc.) represented by a logical expression.

[0072] In the case of performing the determination process based on the AND condition (logical product), the threshold determination unit 204 determines whether all the dose information of multiple detection regions is equal to or higher than the threshold based on the AND condition (logical product). If all the dose information of multiple detection regions is equal to or higher than the threshold, determination information (irradiation stop signal) for stopping the irradiation of radiation is generated and output. For example, if the dose information in the detection region with the lowest dose information among multiple detection regions is equal to or higher than the threshold, the irradiation stop signal is generated and output. In the determination process based on the AND condition (logical product), radiation imaging can be performed without missing the dose in all multiple detection regions.

[0073] Alternatively, in the case of performing the determination process based on the OR condition (logical sum), the threshold determination unit 204 determines whether any dose information of multiple detection regions is equal to or higher than the threshold based on the OR condition (logical sum). If any dose information of multiple detection regions is equal to or higher than the threshold, determination information (irradiation stop signal) for stopping the irradiation of radiation is generated and output.

[0074] For example, if the dose information in the detection region with the highest dose information among multiple detection regions is equal to or higher than the threshold, the irradiation stop signal is generated and output. In the determination process based on the OR condition (logical sum), radiation imaging can be performed while suppressing excessive irradiation of radiation.

[0075] In the case of performing the determination process based on the AVG condition (average), the threshold determination unit 204 determines whether the dose information obtained by averaging the dose information of multiple detection regions is equal to or higher than the threshold based on the AVG condition (average). If the average dose information is equal to or higher than the threshold, determination information (irradiation stop signal) for stopping the irradiation of radiation is generated and output.

[0076] The determination method represented by a logical expression (AND condition, OR condition, AVG condition, etc.) can be set by default, and the radiologic technologist can change the setting of the determination method. Alternatively, the FPD processing unit 200 can change the setting of the logical expression of the determination method according to the imaging condition information set by the imaging condition setting unit 1031. Alternatively, during the imaging of the FPD 102, the FPD processing unit 200 can change the setting of the determination method (AND condition, OR condition, AVG condition, etc.) in the automatic exposure control (AEC) according to the comparison between the monitored signal value and the output information (reference output information) used as a reference.

[0077] has been described with reference to Figure 2 an arrangement in which the functional components of the FPD processing unit 200 are provided in the FPD 102 and the FPD 102 performs the automatic exposure control (AEC) determination function, but the present invention is not limited thereto. The functional components of the FPD processing unit 200 can be provided in the processing unit 1033 of the imaging control device 103, and the imaging control device 103 can perform the AEC determination function. In this case, the FPD 102 can transmit the monitored signal value of each detection area to the imaging control device 103 via the communication IF unit 205, and the processing unit 1033 of the imaging control device 103 can perform processing associated with the AEC determination function based on the received monitored signal value.

[0078] (AEC operation)

[0079] Next, with reference to Figure 3 3A and 3B, the automatic exposure control (AEC) in the case where a registration error occurs in the object with respect to the FPD 102 (which is a problem for the radiographic imaging apparatus 102 according to the first embodiment) will be described. Figure 3Figures 3A and 3B are diagrams showing an example of monitoring signal value changes in automatic exposure control when the position of the object 105 is deviated in the vertical direction on the paper surface with respect to the radiation imaging apparatus 102 (FPD) according to an embodiment. Regarding the detection region 1021, five detection regions A to E will be taken as an example. A plurality of identification information (for example, A to E) is set in the detection region, and each detection region can be identified based on the identification information. Among the five detection regions A to E illustrated here, the detection regions A and B are set on the upper side (upper segment side) of the paper surface within the detection surface of the FPD 102. Compared with the positions of the detection regions A and B, the detection regions D and E are set on the lower side (lower segment side) of the paper surface within the detection surface of the FPD 102. The position of the detection region C in the vertical direction is set between the positions of the detection regions A and B and the positions of the detection regions D and E within the detection surface of the FPD 102. In addition, the position of the detection region C in the horizontal direction is set between the positions of the detection regions A and D and the positions of the detection regions B and E within the detection surface of the FPD 102.

[0080] In Figure 3 Figure 3A, 302 indicates a state where the position of the object 105 is deviated upward on the paper surface with respect to the FPD 102. At this time, the detection regions A to E of the FPD 102 are relatively located below the object 105.

[0081] In the detection region D or E located below (lower segment) the detection regions A to C, since the ratio of the abdominal part with low radiation transmittance in the object structure in the detection region is high, the monitored signal value detected in the detection region D or E will decrease.

[0082] On the other hand, in the detection regions A, B, or C, there is no obvious change in the object structure in the detection region. However, in the detection regions A, B, or C, the ratio of the object structure with the same radiation transmittance increases, so the monitored signal value detected in the detection regions A, B, or C will increase.

[0083] In a state where the object 105 is deviated upward on the paper surface with respect to the FPD 102, compared with the case where the object 105 is located at the center of the FPD 102 (no relative registration error: Figure 3 301 in Figure 3A), the monitored signal value in the detection region D or E will decrease. Therefore, if AEC is performed based on the monitored signal value in the detection region D or E, the time to reach the predetermined dose will become longer, and the object 105 is unnecessarily irradiated with more radiation than the predetermined dose. Alternatively, if AEC is performed based on the monitored signal value in the detection regions A, B, or C, the time to reach the predetermined dose is shorter, and the object 105 is irradiated with less radiation than the predetermined dose.

[0084] Figure 3 FIG. 3B shows a state in which the position of the object 105 is deviated downward on the paper surface with respect to the FPD 102. At this time, the detection regions A to E of the FPD 102 are relatively located above the object 105.

[0085] In the detection regions D or E located below (lower segment) the detection regions A to C, since the ratio of the abdominal part having a low radiation transmittance in the object structure in the detection region is low, the monitored signal value detected in the detection regions D or E increases.

[0086] On the other hand, in the detection regions A, B, or C, the object structure in the detection region does not change significantly. However, in the detection regions A, B, or C, the ratio of the object structures having the same radiation transmittance decreases, and thus the monitored signal value detected in the detection regions A, B, or C decreases.

[0087] In a state where the object 105 is deviated downward on the paper surface with respect to the FPD 102, compared with the case where the object 105 is located at the center of the FPD 102 (no relative registration error), the monitored signal value in the detection regions D or E increases. Therefore, if AEC is performed based on the monitored signal value in the detection regions D or E, the time to reach the predetermined dose becomes shorter, and the object 105 is irradiated with less radiation than the predetermined dose. Alternatively, if AEC is performed based on the monitored signal value in the detection regions A, B, or C, the time to reach the predetermined dose becomes longer, and the object 105 is unnecessarily irradiated with more radiation than the predetermined dose.

[0088] As described above, since the monitored signal value changes due to the relative registration error between the object 105 and the FPD 102, the dose of the reference output (in the case of ideal imaging) changes.

[0089] Figure 7 FIGS. 7A to 7C are graphs each showing an example of a histogram in the case where a registration error occurs in the position of the object 105 with respect to the FPD 102. Figure 7 The histogram 701 shown in FIG. 7A is a histogram indicating a state where no registration error has occurred. The histogram 701 is Figure 3 the histogram in the case 301 where the object 105 is located at the center of the FPD 102 as shown in FIGS. 3A and 3B.

[0090] In this example, α1 represents the output information as a reference (reference output information) in the detection regions A, B, or C, and α2 represents the output information as a reference (reference output information) in the detection regions D or E. β1 represents the number of pixels that output the monitored signal value corresponding to the reference output information α1 in the detection region. Figure 7FIG. 7A shows a state where the object 105 is not misregistered with respect to the FPD 102 (multiple detection regions), and the histogram has peaks in the reference output information α1 in the detection regions A, B, or C and in the reference output information α2 in the detection regions D or E.

[0091] Figure 7 The histogram 702 shown in 7B of FIG. Figure 3 corresponds to 302 in 3A of FIG. 3 and shows a state where the position of the object 105 is deviated upward with respect to the FPD 102. The arrow 710 in the histogram 702 indicates the amount of deviation in the upward direction from the central portion 700 of the FPD 102.

[0092] Since the ratio of the abdominal part with low radiation transmittance in the object structure in the detection regions D or E is high, the number of pixels outputting the monitoring signal value corresponding to the reference output information α2 in the detection regions D or E decreases.

[0093] On the other hand, since the ratio of the object structure with the same radiation transmittance in the detection regions A, B, or C increases, the number of pixels outputting the monitoring signal value corresponding to the reference output information α1 in the detection regions A, B, or C increases. For example, if the threshold determination process is performed based on the AND condition (logical product), compared with the assumed reference output information α2 in the detection regions D or E, the monitoring signal value decreases and the time to reach the threshold becomes longer, so the weighting information is set large.

[0094] Figure 7 The histogram 703 shown in 7C of FIG. Figure 3 corresponds to 303 in 3B of FIG. 3 and indicates a state where the position of the object 105 is deviated downward with respect to the FPD 102. The arrow 720 in the histogram 703 indicates the amount of deviation in the downward direction from the central portion 700 of the FPD 102.

[0095] Since the ratio of the abdominal part with low radiation transmittance in the object structure in the detection regions D or E is low, the number of pixels outputting the monitoring signal value corresponding to the reference output information α2 in the detection regions D or E increases, as shown in the histogram 703.

[0096] On the other hand, since the object structure in the detection regions does not change significantly in the detection regions A, B, or C, but the ratio of the object structure with the same radiation transmittance in the detection regions A, B, or C decreases, the number of pixels outputting the monitoring signal value corresponding to the reference output information α1 in the detection regions A, B, or C decreases. For example, if the threshold determination process is performed based on the OR condition (logical sum), compared with the assumed reference output information α2 in the detection regions D or E, the monitoring signal value increases and the time to reach the threshold becomes shorter, so the weighting information is set small.

[0097] The weighting unit 202 can compare the histogram 702 or 703 obtained by analyzing the monitoring signal values output from each detection region during imaging with the histogram 701 assumed as a reference. Then, the weighting unit 202 can obtain the peak ratio through pattern matching, thereby obtaining the registration error (registration error amount and registration error direction) of the object 105 with respect to each detection region in the FPD 102. If no registration error occurs, the peaks in the histogram 702 or 703 can have the same pattern as the peaks in the reference histogram 701. The reference histogram 701 can be stored, for example, in association with the imaging condition information in Figure 9 the table shown, and the pattern of the histogram 701 can be obtained together with the reference weighting information and the reference output information.

[0098] Next, the weighting in the radiation imaging apparatus 102 according to the first embodiment will be described. The weighting unit 202 of the FPD processing unit 200 generates the weighting information for each detection region based on the comparison between the reference value (reference output information) of the output signal and the monitoring signal values output from each detection region. For each detection region, the reference weighting information transmitted from the reference weighting unit 1038 of the imaging control device 103 is set as the initial value of the weighting information for each detection region. The weighting unit 202 changes the reference weighting information set as the initial value according to the weighting information generated based on the comparison between the reference output information and the monitoring signal values output from each detection region in real time. The weighting unit 202 sets the weighting information indicating the weight of each detection region among the plurality of detection regions.

[0099] The weighting unit 202 weights the monitoring signal values (combined monitoring signal values) output from the signal combining unit 201 by using the weighting information. When performing automatic exposure control (AEC), the weighting unit 202 generates dose information (weighted monitoring signal values (combined monitoring signal values)) based on the weighting information for each detection region and the monitoring signal values (combined monitoring signal values) output from the signal combining unit 201. The weighting unit 202 weights the monitoring signal values (combined monitoring signal values) by calculating the weighting information for the monitoring signal values (multiplying the monitoring signal values by the weighting information). The calculation of the weighting information set for each detection region will be described in detail later.

[0100] Note that the monitoring signal values (combined monitoring signal values) used for calculation can be, for example, the average of the monitoring signal values of the detection pixels included in each detection region, or the average of the monitoring signal values of a predetermined number of detection pixels selected from the plurality of detection pixels included in the detection region.

[0101] Based on the dose information (weighted monitoring signal value) generated by the weighting unit 202 or the weighted average value of the weighted monitoring signal values, the threshold determination unit 204 generates determination information for determining whether to continue automatic exposure control (AEC). The weighted average value can be set to a value given by (a*l + b*m + c*n +... + e*p) / (l + m + n +... + p), where a, b, c,..., and e represent the monitoring signal values detected in each detection region, and l, m, n,..., and p represent the weights corresponding to the monitoring signal values in each detection region.

[0102] Next, an overview of generating weighted information and performing AEC determination using the registration error information of the object 105 in the radiation imaging apparatus 102 according to the first embodiment will be described. Figure 4A and Figure 4B is a diagram showing an example of weighting based on dose information in the case where the position of the object 105 deviates upward on the paper surface with respect to the radiation imaging apparatus 102 (FPD) according to the first embodiment. Reference will be made to Figure 4A and Figure 4B to illustrate the weighted information generation process based on dose information in the state where the position of the object 105 deviates upward on the paper surface with respect to the FPD 102 during imaging of the anterior chest.

[0103] Referring to Figure 4A , the following case will be taken as an example, in which the exposure index (EI) value as the dose index value is used as the output information (reference output information) for reference of the monitoring signal value. The weighting unit 202 can store the reference output information of the monitoring signal value in the internal memory, or obtain the reference output information of the monitoring signal value stored in the storage unit 1036 from the imaging control device 103 via the communication IF unit 205. The same component as the storage unit 1036 can be provided in the FPD processing unit 200 and can store the table or information obtained from the imaging control device 103. That is, the FPD processing unit 200 can include an internal storage unit that stores imaging condition information for capturing a radiation image, and reference weighting information and reference output information for a plurality of detection regions associated with the imaging condition information.

[0104] In this example, the case where the position of object 105 is set at the center of FPD 102 (a state where no relative registration error occurs) is set as a reference. The weighting unit 202 generates weighting information set for each detection area by comparing the monitoring signal value in each detection area with output information (reference output information) obtained based on the position of the reference object relative to FPD 102 (multiple detection areas). For example, the weighting unit 202 may set the signal value (signal information) obtained from an image of the same object 105 captured in the past as the reference output information for the monitoring signal value used as a reference. At this time, for example, an image of the same object 105 captured in the past may be stored in the internal memory of the weighting unit 202, or stored in the storage unit 1036 of the imaging control device 103. The weighting unit 202 may acquire the image information of object 105 from the internal memory, or may acquire the image information of the same object 105 captured in the past from the imaging control device 103 via the communication IF unit 205.

[0105] As Figure 4A shown in the display example 401, the reference output information of the monitoring signal values in detection areas A to E is 300 in detection area A (A: 300), 300 in detection area B (B: 300), 100 in detection area C (C: 100), 150 in detection area D (D: 150), and 150 in detection area E (E: 150).

[0106] The weighting unit 202 receives the monitoring signal value of the detection area selected from multiple detection areas in FPD 102. In Figure 4A the example shown in the display example 402, detection areas A to E are the selected detection areas, and the monitoring signal values detected in each detection area are 360 in detection area A (A: 360), 360 in detection area B (B: 360), 120 in detection area C (C: 120), 120 in detection area D (D: 120), and 120 in detection area E (E: 120).

[0107] In a state where object 105 is deviated upward relative to FPD 102, since the ratio of the abdominal part with low radiation transmittance in the object structure in detection area D or E is high, the monitoring signal value (D: 120 or E: 120) detected in detection area D or E is reduced compared with the reference output information (D: 150 or E: 150), and is reduced to 0.8 times of the reference output information.

[0108] On the other hand, in detection regions A, B, or C, there is no obvious change in the object structure in the detection region. However, compared with the reference output information (A: 300, B: 300, or C: 100), the monitored signal values detected in detection regions A, B, or C (A: 360, B: 360, or C: 120) increase and increase to 1.2 times the reference output information.

[0109] Therefore, when the monitored signal value in detection region D or E decreases, the time to reach the predetermined dose becomes longer, and the dose given to object 105 increases. The weighting unit 202 calculates the deviation of the monitored signal value from the reference output information and calculates the weight for each detection region.

[0110] The weighting unit 202 performs an operation of dividing the reference output information by the detected monitored signal value (reference output information / detected monitored signal value) to obtain information representing the deviation of the monitored signal value from the reference output information (reference output ratio: the output ratio relative to the reference output information) (display example 403).

[0111] As Figure 4A shown in display example 403, the information representing the deviation of the monitored signal value from the reference output information (the output ratio relative to the reference output information) is A: 300 / 360 = 0.83 in detection region A and B: 300 / 360 = 0.83 in detection region B ( Figure 4A of display example 403). In addition, this information is C: 100 / 120 = 0.83 in detection region C, D: 150 / 120 = 1.25 in detection region D, and E: 150 / 120 = 1.25 in detection region E ( Figure 4A of display example 403).

[0112] For detection regions A, B, or C where the object structure has not changed, the weighting unit 202 sets "1" as the weight for the current monitored signal value and maintains the current monitored signal value ( Figure 4A of 404).

[0113] When the weighting unit 202 obtains the monitored signal value of detection region D such that the relationship between the monitored signal value of detection region A (monitored signal value A: 360) and the monitored signal value of detection region D satisfies the ratio 2:1 of the reference output information (A(300): D(150)), the required monitored signal value in detection region D is D: 180. On the other hand, the current monitored signal value in detection region D is D: 120, and the weighting unit 202 sets the weight "1.5" for detection region D, which is required to satisfy the ratio 2:1 of the reference output information ( Figure 4A404). Similar to detection area D, the weighting unit 202 sets the weight "1.5" for detection area E ( Figure 4A 404).

[0114] In this case, for example, by multiplying the monitoring signal value "360" in detection area A by the weighting information "1", the weighting unit 202 obtains the weighted monitoring signal value "360". Similarly, by multiplying the monitoring signal value "120" in detection area D by the weighting information "1.5", the weighting unit 202 obtains the weighted monitoring signal value "180", and the ratio between the weighted monitoring signal values is obtained as A (A: 360): D (D: 180) = 2:1. The ratio (2:1) between the weighted monitoring signal values is equal to the ratio between the reference output information (A (300): D (150) = 2:1) ( Figure 4A Display example 401). The weighting unit 202 of the FPD processing unit 200 generates weighting information to reduce the deviation between the output signal (monitoring signal value) and the reference output information.

[0115] In Figure 4A In the example shown, imaging is pre - performed in a state where the position of the object 105 is deviated relative to the FPD 102, and the generated reference output information and reference weighting information are acquired and stored in Figure 9 the table shown. Note that the disclosed technology is not limited to Figure 4A the example shown, and can be applied to the case where the weighting information for each detection area is calculated during radiation irradiation and the reference weighting information set to the initial value is changed.

[0116] The weighting unit 202 of the FPD processing unit 200 obtains the ratio between the output signals (monitoring signal values) output from a predetermined detection area during the capture of a radiation image, and generates weighting information to match the ratio between the output signals (monitoring signal values) and the ratio between the reference output information. Taking Figure 4B as an example to illustrate the case of generating weighting information using the ratio between the reference output information (reference output ratio) in a specific detection area during radiation irradiation. The weighting unit 202 sets the ratio between the reference output information (reference output ratio) as a reference based on the stored reference output information. In Figure 4B display example 411, the reference output ratio in detection areas A and D is A: D = 2:1. The reference output ratio in detection areas B and E is B: E = 2:1.

[0117] The weighting unit 202 receives the monitoring signal values of detection areas A to E selected from multiple detection areas in the FPD 102, analyzes the monitoring signal values of each of detection areas A to E, and obtains the output ratio between the monitoring signal values of each of detection areas A to E.

[0118] As Figure 4B shown in display example 412, the output ratio between the monitoring signal value 360 (A: 360) in detection area A and the monitoring signal value 120 (D: 120) in detection area D is A:D = 3:1. Similarly, the output ratio between the monitoring signal value 360 (B: 360) in detection area B and the monitoring signal value 120 (E: 120) in detection area E is B:E = 3:1.

[0119] For example, for detection areas A and D, the weighting unit 202 compares the output ratio (3:1) between the monitoring signal values of each acquired detection area with the output ratio as a reference between the detection areas (reference output ratio (2:1)). Then, the weighting unit 202 calculates the weight for each detection area to obtain an output ratio equal to the output ratio as a reference between the detection areas (reference output ratio). As Figure 4B shown in display example 413, the weighting unit 202 sets weights for each of detection areas A to E to obtain an output ratio equal to the reference output ratio (A:D = B:E = 2:1). More specifically, the weighting unit 202 sets the weighting information for each detection area as A:1, B:1, C:1, D:1.5, and E:1.5.

[0120] The weighting unit 202 generates dose information (weighted monitoring signal value) by performing the operation of "weighting information" * "monitoring signal value" on each monitoring signal value received from the signal combining unit 201 based on the set weighting information, and transmits the dose information to the threshold determination unit 204.

[0121] The threshold determination unit 204 determines whether the weighted monitoring signal value exceeds the threshold (condition) based on a determination method represented by a logical expression (AND condition, OR condition, AVG condition, etc.). If the weighted monitoring signal value exceeds the threshold, the threshold determination unit 204 generates determination information (irradiation stop signal) indicating that the weighted monitoring signal value exceeds the threshold via the communication IF unit 205, and transmits the determination information to the imaging control device 103 via the communication IF unit 205.

[0122] In the example described with reference to Figure 4A and Figure 4B the case where the weighting unit 202 stores the reference output information has been illustrated. However, the present invention is not limited thereto, and the weighting unit 202 can generate the weighting information without storing the reference output information. It will be described with reference to Figure 5Describe the case where the weighting unit 202 can generate weighting information without saving the reference output information as a reference. If imaging is performed on the imaging part of an object using detection areas at laterally symmetric positions with respect to each other among a plurality of detection areas, the weighting unit 202 of the FPD processing unit 200 generates weighting information so as to obtain an equal ratio between output signals (monitoring signal values) output from the detection areas at laterally symmetric positions with respect to each other during capture of a radiation image.

[0123] In Figure 5 In the example shown, in the case of frontal imaging where an equal output ratio is obtained between the left monitoring signal value in the left detection area and the right monitoring signal value in the right detection area, the weighting unit 202 generates weighting information by assuming an equal output ratio is obtained between the monitoring signal values in the left detection area and the right detection area. The weighting unit 202 can determine the imaging part of the object 105 based on the imaging condition information acquired from the imaging control device 103 via the communication IF unit 205, and determine whether the imaging is imaging where an equal output ratio is obtained between the monitoring signal values in the left detection area and the right detection area (frontal imaging). If the imaging is imaging where an equal output ratio is obtained between the monitoring signal values in the left detection area and the right detection area (frontal imaging), the weighting unit 202 uses lateral symmetry to generate weighting information.

[0124] In Figure 5 In the display example 501 shown, in the imaging of the front of the chest, the position of the object 105 is deviated to the right with respect to the FPD 102, and the output ratio between the monitoring signal values output from the left detection area A and the right detection area B is A:B = 3:4.

[0125] The weighting unit 202 obtains an average output ratio of 3.5 (= (3 + 4) / 2) between the monitoring signal values, so that the left quantity and the right quantity in the output ratio between the monitoring signal values of the left detection area A and the right detection area B are equal to each other. The average output ratio between the monitoring signal values (A:B = 3.5:3.5) can be the reference output ratio between the monitoring signal values in the left detection area and the right detection area. The weighting unit 202 calculates the weights for the left detection area A and the right detection area B to obtain an output ratio equal to the average output ratio between the monitoring signal values. In this case, the weighting unit 202 obtains 1.17 (= 3.5 / 3) as the weighting information for the detection area A ( Figure 5 of the display example 502). In addition, the weighting unit 202 obtains 0.88 (= 3.5 / 4) as the weighting information for the detection area B ( Figure 5 of the display example 502).

[0126] It may happen that there is an obstacle such as a pacemaker inside the object 105, and the deviation between the monitoring signal value output from the detection area and the reference output information as a reference is extremely large. In this case, the registration error of the object 105 may be erroneously inferred, and the weighting information may not be correctly generated. To cope with this situation, the FPD processing unit 200 may have a function capable of selecting not to perform weighting. If it is known in advance that there is an obstacle inside the object 105, the imaging condition setting unit 1031 may be able to select not to perform weighting. The information indicating non-execution of weighting (weighting non-execution information) is transmitted to the FPD processing unit 200 of the FPD 102 via the communication IF unit 1037. If the weighting non-execution information is received via the communication IF unit 205, the weighting unit 202 of the FPD processing unit 200 may prevent the generation of weighting information.

[0127] Alternatively, according to the analysis result of the monitoring signal value, weighting may not be performed during the radiation irradiation. For example, if the deviation between the monitoring signal value output from the detection area and the reference output information as a reference is equal to or greater than a predetermined value, the weighting unit 202 may prevent the execution of weighting. At this time, the weighting unit 202 may transmit the information indicating non-execution of weighting (weighting non-execution information) to the display control unit 1035 of the imaging control device 103 via the communication IF unit 205, and display the information indicating non-execution of weighting on the display unit 106, thereby notifying the operator.

[0128] (Second Embodiment)

[0129] Next, a second embodiment of the disclosed technology will be described. The first embodiment has illustrated an arrangement for generating weighting information using the registration error information of the object 105 relative to the FPD 102. The second embodiment will describe an arrangement for generating weighting information using the deviation information of the standard reference physique information relative to the physique information of the object 105 (such as the size and body thickness of the object).

[0130] Figure 6 FIG. 6A is a diagram illustrating a case of imaging an infant as an object. It will be described with reference to Figure 6 FIG. 6A the case where the monitoring signal value deviates from the reference output information as a reference due to the influence of the small object size compared to the standard reference physique information. In this example, the detection area of the FPD 102 will be described by taking as an example the case where there are nine detection areas A to I arranged in 3 rows × 3 columns and the selected detection areas from the nine detection areas A to I are three detection areas D, E, and F.

[0131] If the size of object 105 is smaller than the standard reference physical information used as a reference, in the selected detection regions D, E, and F, X-rays may not be transmitted through object 105, thereby generating a direct exposure region where X-rays directly enter FPD 102. For example, a direct exposure region is not generated in the central detection region E, while direct exposure regions may be generated in the detection regions D and F located on the left and right sides of the detection region E.

[0132] The weighting unit 202 of the FPD processing unit 200 compares the distributions of the peaks of the output signals (monitoring signal values) of multiple detection regions to specify the detection regions of the output signals whose peaks are greater than the reference output information, and then sets the weighting information of the specified detection regions to be less than the weighting information of the detection regions whose output signals correspond to the reference information. Figure 6 6B of shows graphs each showing the result of performing a histogram analysis on the monitoring signal values for each detection region. As Figure 6 shown in 601 of 6B of, in the detection region E where no direct exposure region is generated, the peak hardly deviates from the reference output information α. On the other hand, as Figure 6 shown in 602 of 6B of, in each of the detection regions D and F where a direct exposure region is generated, the peak of the output information α’ of the monitoring signal value of the detection region where the direct exposure region is generated is greater than the reference output information α. That is, the peak deviates from the reference output information α. To address this situation, the weighting unit 202 can reduce the weight of each of the detection regions D and F, thereby reducing the impact of the generation of the direct exposure region on the AEC determination (determining whether a predetermined cumulative dose is reached).

[0133] In this example, if the monitoring signal value is the average value in the detection region, the weighting unit 202 can obtain the monitoring signal value M(D, E) in the detection region D or F through the following formula:

[0134] Monitoring signal value M(D, E) ≈ α + (α’ - α) × β’ / (β + β’) (1)

[0135] where α represents the output information used as a reference (reference output information), and α’ represents the output information of the monitoring signal value in the detection region where a direct exposure region is generated. β represents the number of pixels in the detection region that output the monitoring signal value corresponding to the reference output information α, and β’ represents the number of pixels in the detection region that output the monitoring signal value α’, where a direct exposure region is generated.

[0136] The weighting unit 202 only needs to set the weighting information such that the average value M of the monitoring signal values in the direct exposure area is close to the reference output information α. In this case, the weighting unit 202 can obtain the weighting information given by the following formula using the monitoring signal value M(D,E) obtained by the above formula (1):

[0137] Weighting information = α / M(D,E) (2)

[0138] The type of the monitoring signal value used for AEC threshold determination can be changed. For example, in AEC threshold determination, if it is set to use the maximum value of the monitoring signal values in the selected detection area, when it is known from histogram analysis that the influence of the direct exposure area is large, the type of the monitoring signal value can be changed to use the minimum value of the monitoring signal values in the selected detection area. Alternatively, the logical operation for comparing the monitoring signal value with the threshold for determining AEC can be changed.

[0139] has been referred to Figure 6 Examples in which the size of the object 105 is different from the standard reference physical information in the left - right direction of the FPD 102 have been described in FIGS. 6A and 6B, but the present invention is not limited thereto. The disclosed technology can be similarly applied to the case where the body thickness of the object 105 is different from the standard reference physical information.

[0140] Figure 8 FIG. is a diagram showing an example of the configuration of a radiation imaging system 100 including a radiation imaging device 102 according to the second embodiment. The basic system configuration is the same as that of the radiation imaging system 100 described in the first embodiment, and an imaging control device 103 and a radiation imaging device 102 that captures a radiation image based on the radiation emitted from a radiation source 101 are provided. The imaging control device 103 is connected to the radiation imaging device 102 and a radiation control device 104 that controls the radiation source 101 through, for example, a wired or wireless network or a dedicated line, and controls radiation imaging using the radiation imaging device 102 and the radiation source 101.

[0141] The radiation imaging system 100 according to the second embodiment is provided with an optical imaging device 900 (for example, an optical camera) that captures an optical image of the object 105. As a functional component of the processing unit 1033, a physical information acquisition unit 1039 is added. For example, the optical imaging device 900 can be arranged near the radiation source 101. The optical imaging device 900 is not limited to a single optical imaging device 900, but a plurality of optical imaging devices 900 can be used. The optical imaging device 900 acquires an optical image of the object 105 before performing radiation imaging. The optical image acquired by the optical imaging device 900 is transmitted to the processing unit 1033.

[0142] The physical information acquisition unit 1039 acquires the physical information of the object based on the optical image of the object captured by the optical imaging device 900, and acquires the deviation from the reference physical information used as a reference. The physical information acquisition unit 1039 extracts the physical information representing the characteristics (such as body width and body thickness) of the object 105 by performing image processing for extracting the contour on the optical image acquired by the optical imaging device 900. The physical information acquisition unit 1039 acquires the difference between the reference physical information and the physical information of the object 105 by comparing the acquired physical information of the object 105 with the standard reference physical information corresponding to the age, gender, etc. of the object 105.

[0143] If the acquired difference has a value falling within a predetermined range, the reference weighting unit 1038 may determine that the reference physical information matches the physical information of the object 105. On the other hand, if the acquired difference falls outside the predetermined range, the reference weighting unit 1038 determines that the physical information of the object 105 is different from the reference physical information, and changes the reference weighting information and the reference output information set for each detection area based on the difference.

[0144] Figure 10 FIG. is an example of a table stored in the storage unit 1036, which stores the reference physical information, the reference output information, and the reference weighting information corresponding to the age, gender, etc. of the object 105. In this table, a reference value (reference output information) of the output signal in each detection area and the reference weighting information in each detection area are set for each piece of reference physical information.

[0145] For example, if the physical information of the object 105 is different from the reference physical information H1, the reference weighting unit 1038 changes the reference output information (S1-11, S1-22,...) and the reference weighting information (W1-11, W1-22,...) set for each detection area based on the difference between the reference physical information H1 and the physical information of the object 105, so as to reduce the value of the difference between the physical information. The reference weighting unit 1038 acquires the changed reference output information and reference weighting information as initial values, and transmits them to the FPD 102 via the communication IF unit 1037. The weighting unit 202 in the FPD processing unit 200 sets the reference output information and the reference weighting information transmitted from the reference weighting unit 1038 as the reference values in each detection area, and captures the radiation image of the object 105.

[0146] According to the present embodiment, even if the physical information of the object 105 is different from the standard reference physical information, it is possible to change the reference output information and the reference weighting information in each detection area in consideration of the difference in the physical information of the object 105. This can suppress the change in the radiation dose in the automatic exposure control.

[0147] (Third Embodiment)

[0148] Figure 11 FIG. showing an example of the configuration of a radiation imaging system 100 including a radiation imaging device 102 according to the third embodiment. The basic system configuration is the same as that of the radiation imaging system 100 described in the first embodiment, and an imaging control device 103 and a radiation imaging device 102 for capturing a radiation image based on the radiation emitted from a radiation source 101 are provided. The imaging control device 103 is connected to the radiation imaging device 102 and a radiation control device 104 that controls the radiation source 101 through, for example, a wired or wireless network or a dedicated line, and controls radiation imaging using the radiation imaging device 102 and the radiation source 101.

[0149] The radiation imaging system according to the third embodiment is provided with an optical imaging device 900 (e.g., an optical camera) that captures an optical image of an object 105. As a functional component of the processing unit 1033, a relative information acquisition unit 1040 is added. For example, the optical imaging device 900 may be arranged near the radiation source 101. The optical imaging device 900 acquires an optical image of the object 105 before performing radiation imaging. The optical image acquired by the optical imaging device 900 is transmitted to the processing unit 1033.

[0150] The relative information acquisition unit 1040 uses the optical image of the object captured by the optical imaging device 900 to acquire the registration error of the object with respect to a plurality of detection regions. By performing image processing on the optical image acquired by the optical imaging device 900, the relative information acquisition unit 1040 acquires a skeleton model of the object 105 obtained by extracting the body shape contour of the object 105. The relative information acquisition unit 1040 calculates the positional relationship between the respective detection regions of the FPD 102 based on the skeleton model of the object 105 and the optical image. Then, the relative information acquisition unit 1040 calculates the relative registration error information with respect to each detection region by comparing the positional relationship calculated based on the skeleton model and the optical image with the ideal positional relationship between the object and each detection region pre-stored. Before capturing the radiation image of the object 105, the relative information acquisition unit 1040 acquires the relative registration error with respect to each detection region in the FPD 102 based on the optical image of the object 105. The acquired relative registration error includes, for example, a state in which the position of the object 105 is deviated upward on the paper surface with respect to the FPD 102 (as shown in 302 of 3A of Figure 3 ), and a state in which the position of the object 105 is deviated downward on the paper surface with respect to the FPD 102 (as shown in Figure 3as shown in 303 of 3B). Note that the registration error is not limited to the registration error in the up-down direction, but also includes the error in the left-right direction. The ideal positional relationship between the detection area and the object includes, for example, the case where the object 105 is located at the center of the FPD 102, as described in 301 of 3A using Figure 3 described in 301 of 3A.

[0151] The imaging condition setting unit 1031 receives the imaging condition information input by the operator via the operation input unit 108, and transmits the received imaging condition information to the imaging control unit 1032 and the processing unit 1033.

[0152] If no relative registration error occurs (the ideal positional relationship is obtained), the reference weighting unit 1038 of the processing unit 1033 sets the reference output information and the reference weighting information for the detection area in the FPD 102 based on the imaging condition information set by the imaging condition setting unit 1031.

[0153] If there are multiple detection areas in the pixel area of the FPD 102, the reference weighting unit 1038 sets the reference output information and the reference weighting information for each detection area. In the case where no registration error occurs, the reference weighting unit 1038 obtains the reference output information and the reference weighting information from, for example, a table stored in the storage unit 1036.

[0154] On the other hand, in the case where a relative registration error is obtained (a registration error occurs), the reference weighting unit 1038 of the processing unit 1033 changes the reference output information and the reference weighting information of the detection area in the FPD 102 based on the relative registration error information.

[0155] For example, in the case of the imaging condition information D1, if a relative registration error of the object 105 with respect to the FPD 102 is obtained, the reference weighting unit 1038 changes the reference output information (S1-1, S1-2,...) and the reference weighting information (W1-1, W1-2,...) set for each detection area according to the imaging condition information D1 to reduce the relative registration error amount. The reference weighting unit 1038 obtains the changed reference output information and the reference weighting information as initial values, and transmits them to the FPD 102 via the communication IF unit 1037.

[0156] The weighting unit 202 in the FPD processing unit 200 sets the reference output information and the reference weighting information transmitted from the reference weighting unit 1038 as reference values in each detection area, and captures the radiation image of the object 105. The FPD processing unit 200 generates determination information for controlling the irradiation of the radiation by comparing the dose information obtained by weighting the output signal (monitoring signal value) based on the changed weighting information with a preset threshold value.

[0157] According to this embodiment, even if a relative registration error occurs between the object 105 and each detection area of the FPD 102, it is possible to change the reference output information and the reference weighting information in each detection area in consideration of the amount of relative registration error between each detection area of the FPD 102 and the position of the object 105. This can suppress the change in the radiation dose in the automatic exposure control.

[0158] Other embodiments

[0159] Embodiments of the present invention can also be implemented by a computer of a system or device 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 the functions of one or more of the above-described (one or more) embodiments, and / or the system or device includes one or more circuits (e.g., an application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described (one or more) embodiments, and is implemented by a method executed by the computer of the system or device in the following manner: for example, reading and executing computer-executable instructions from the storage medium to perform the functions of one or more of the above-described (one or more) embodiments, and / or controlling one or more circuits to perform the functions of one or more of the above-described (one or more) embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)) and may include a network of individual computers or individual processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer from, for example, a network or a storage medium. The storage medium may include, for example, one or more of a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disc (such as a compact disc (CD), a digital versatile disc (DVD), or a Blu-ray disc (BD) TM )、a flash device, a memory card, etc.

[0160] Other embodiments

[0161] Embodiments of the present invention can also be implemented by the following method, that is, software (program) that performs the functions of the above-described embodiments is provided to a system or device through a network or various storage media, and the computer or the central processing unit (CPU) or the microprocessing unit (MPU) of the system or device reads and executes the program.

[0162] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the following claims should be given the broadest interpretation to cover all such modifications as well as equivalent structures and functions.

Claims

1. A radiation imaging apparatus, comprising a plurality of receiving fields in which a radiation dose can be detected during radiation imaging in which a radiation irradiation device emits radiation, and the radiation imaging apparatus can perform processing for stopping irradiation based on a dose detection result in at least one of the plurality of receiving fields, the radiation imaging apparatus comprising: One or more controllers are configured to adjust parameters associated with a receiving field for dose detection based on registration error information of an object during the radiation imaging.

2. The device according to claim 1, wherein: The one or more controllers: processing output signals output from a plurality of detection areas, the plurality of detection areas being provided in a pixel area in which a plurality of pixels each for detecting radiation are arranged and the plurality of detection areas including detection pixels each for outputting a signal corresponding to a radiation dose, generating weighting information for each of the plurality of detection areas by comparing the output signal with preset reference information, and Determination information for controlling irradiation of radiation is generated by comparing dose information obtained by weighting the output signal based on the weighting information with a preset threshold value.

3. The device according to claim 2, wherein: The reference information includes reference output information output from each of the plurality of detection areas when no registration error occurs with respect to the plurality of detection areas, and The one or more controllers generate the weighting information to reduce a deviation of the output signal relative to the reference output information.

4. The device according to claim 3, wherein: The one or more controllers include a memory configured to store imaging condition information for capturing a radiographic image, and the reference output information and reference weighting information for each of the plurality of detection areas associated with the imaging condition information.

5. The device according to claim 4, wherein: The one or more controllers: acquiring the reference output information and the reference weighting information associated with the imaging condition information from the memory, and The reference weighting information set to an initial value before capturing the radiographic image is changed based on the weighting information generated during capturing of the radiographic image.

6. The device according to claim 3, wherein: The reference information includes a ratio between reference output information in predetermined detection areas among the plurality of detection areas, The one or more controllers acquire a ratio between output signals output from the predetermined detection area during capture of a radiographic image, and The weighting information is generated so that a ratio between the output signals matches a ratio between the reference output information.

7. The device according to claim 2, wherein: The one or more controllers generate the weighting information for a detection area selected from the plurality of detection areas.

8. The device according to claim 2, wherein: When imaging of an imaging portion of the object is performed using detection areas among the multiple detection areas that are located at laterally symmetrical positions with respect to each other, the one or more controllers generate the weighting information to obtain an equal ratio between output signals output from the detection areas that are located at laterally symmetrical positions with respect to each other during capture of the radiographic image.

9. The device according to claim 2, wherein: The one or more controllers: comparing the distribution of peaks of the output signals of the plurality of detection regions, specifying a detection area of ​​an output signal that outputs a peak greater than the reference information, and The weighting information of the designated detection area is set to be smaller than the weighting information of the detection area that outputs the output signal corresponding to the reference information.

10. The device according to claim 2, wherein: In a case where the deviation between the output signal and the reference information is not less than a predetermined value, the one or more controllers do not generate the weighting information.

11. The device according to claim 5, wherein: The one or more controllers set, as the initial value, weighting information obtained by changing the reference weighting information based on a registration error of the object with respect to the plurality of detection areas acquired using an optical image of the object.

12. The device according to claim 4, wherein: The one or more controllers set weighting information obtained by changing the reference weighting information based on a deviation between preset reference physical information and physical information of the subject acquired using an optical image of the subject as an initial value.

13. The device according to claim 1, wherein: The one or more controllers: processing output signals output from a plurality of detection areas, the plurality of detection areas being provided in a pixel area in which a plurality of pixels each for detecting radiation are arranged and the plurality of detection areas including detection pixels each for outputting a signal corresponding to a radiation dose, generating weighting information for each of the plurality of detection areas by comparing the output signal with preset reference information, and Determination information for controlling irradiation of radiation is generated by comparing dose information obtained by weighting the output signal based on the weighting information with a preset threshold value.

14. The device according to claim 1, wherein: The one or more controllers: acquiring physical information of the subject based on an optical image of the subject captured by an optical imaging unit, and acquiring a deviation from reference physical information serving as a reference, changing weighting information serving as a reference based on the deviation of the physical information, processing output signals output from a plurality of detection areas, the plurality of detection areas being provided in a pixel area in which a plurality of pixels each for detecting radiation are arranged, and the plurality of detection areas including detection pixels each for outputting a signal corresponding to a radiation dose, and The irradiation of radiation is controlled by comparing dose information obtained by weighting the output signal based on the changed weighting information with a preset threshold value.

15. The device according to claim 1, wherein: The one or more controllers: using an optical image of the object captured by an optical imaging unit to obtain a registration error of the object relative to a plurality of detection areas, The weighted information used as a reference is changed based on the registration error, processing output signals output from a plurality of detection areas, the plurality of detection areas being provided in a pixel area in which a plurality of pixels each for detecting radiation are arranged, and the plurality of detection areas including detection pixels each for outputting a signal corresponding to a radiation dose, and Determination information for controlling irradiation of radiation is generated by comparing dose information obtained by weighting the output signal based on the changed weighting information with a preset threshold value.

16. The device according to claim 1, wherein The one or more controllers: acquiring dose distribution information based on first dose detection information acquired at a first timing during radiation irradiation after the radiation irradiation apparatus starts irradiation of radiation, updating weighting information associated with a receiving field used for dose detection based on the dose distribution information corresponding to the registration error information, and Communication for stopping irradiation is performed based on second dose detection information acquired at a second timing during the radiation irradiation, the updated weighting information, and threshold information of the reception field for dose detection.

17. The device according to claim 1, wherein: The one or more controllers: acquiring an optical image of the object at the start of radiation imaging or after the start of radiation imaging, updating weighting information associated with a reception field for dose detection based on the optical image corresponding to the registration error information, and Communication for stopping irradiation is performed based on the second dose detection information acquired at the second timing during radiation irradiation, the updated weighting information, and the threshold information of the reception field used for dose detection.

18. A radiation imaging method of a radiation imaging apparatus, the radiation imaging apparatus comprising a plurality of receiving fields in which a radiation dose can be detected during radiation imaging in which a radiation irradiation device emits radiation, and the radiation imaging apparatus can perform processing for stopping irradiation based on a dose detection result in at least one of the plurality of receiving fields, the radiation imaging method comprising: Parameters associated with a receiving field for dose detection are adjusted based on registration error information of the object at the time of the radiation imaging. 19 . A program product for causing a computer to execute the radiation imaging method according to claim 18 . 20 . A storage medium storing a program for causing a computer to execute the radiation imaging method according to claim 18 .

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