CN117958846A

CN117958846A - Radiation imaging system

Info

Publication number: CN117958846A
Application number: CN202311354043.5A
Authority: CN
Inventors: 西岛胜浩; 山田大辅; 小原一诚
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2022-10-27
Filing date: 2023-10-19
Publication date: 2024-05-03

Abstract

The present invention relates to a radiation imaging system. The present invention relates to a radiation imaging system. The radiation imaging system includes: a radiation imaging apparatus configured to transmit a signal related to control of irradiation with radiation to an external apparatus based on a charge generated in response to irradiation with radiation and a target value; and a control device configured to generate a target dose index value based on the target value and a dose index value based on the information about the electric charge, and determine whether the dose index value is within an allowable range of the target dose index value.

Description

Radiation imaging system

Technical Field

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

Background

As a radiation imaging apparatus for medical image diagnosis or nondestructive inspection using radiation such as X-rays, a radiation imaging apparatus including a matrix substrate having a pixel array in which a switch such as a Thin Film Transistor (TFT) and a conversion element such as a photoelectric conversion element are combined has been put into practical use.

In recent years, versatility of radiation imaging apparatuses has been studied. For example, it has been studied to monitor the incorporation of functions of irradiation with radiation. This function enables, for example, detection of timing at which radiation starts to be emitted from the radiation source, detection of timing at which irradiation with radiation is to be stopped, and detection of the amount of irradiation with radiation or the integrated (integral) amount of irradiation.

Japanese patent laid-open No.2021-191391 discloses that the radiation imaging apparatus and the radiation control apparatus perform wireless communication to transmit signals related to exposure control, and the radiation imaging apparatus instructs the radiation control apparatus to stop irradiation with radiation. If an irradiation stop signal indicating that irradiation with radiation has stopped is not received from the radiation control apparatus until the first time elapses after the transmission of the stop instruction signal, the radiation imaging apparatus transmits the stop instruction signal to the radiation control apparatus again. Thus, a technique advantageous in suppressing a decrease in accuracy of exposure control due to communication failure is provided.

The use of Automatic Exposure Control (AEC) makes it possible to capture radiographic images at optimal doses.

However, the technique disclosed in japanese patent laid-open No.2021-191391 is susceptible to improvement in determining or confirming whether the AEC is operating correctly.

Disclosure of Invention

In view of these problems, the present invention relates to a technique of determining whether an AEC is operating correctly.

A first radiation imaging system according to an embodiment of the present invention includes a radiation imaging apparatus and a control apparatus. The radiation imaging apparatus includes: a conversion unit configured to generate electric charges in response to irradiation with radiation; and a transmission unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the conversion unit and a target value. The control device includes: a dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus; an allowable range setting unit configured to set an allowable range of the target dose index value; and a determining unit configured to determine whether the dose index value is within the allowable range.

A second radiation imaging system according to an embodiment of the present invention includes a radiation imaging apparatus and a control apparatus. The radiation imaging apparatus includes: a conversion unit configured to generate electric charges in response to irradiation with radiation; and a transmission unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the conversion unit and a target value. The control device includes: a dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus; an allowable range setting unit configured to set an allowable range of the target dose index value; and a determining unit configured to determine whether the dose index value is within the allowable range. The conversion unit includes a plurality of regions. The signal transmitted by the transmission unit is a signal for providing an instruction to stop irradiation with radiation, the signal being transmitted based on the charge of each of the plurality of regions, the target value, and a stop condition. The dose indicator generating unit is configured to generate a dose indicator value for each of the plurality of regions of the converting unit. The determination unit is configured to determine whether a minimum dose index value among the dose index values of the plurality of regions is within the allowable range, if the stop condition is an AND.

A third radiation imaging system according to an embodiment of the present invention includes a radiation imaging apparatus and a control apparatus. The radiation imaging apparatus includes: a conversion unit configured to generate electric charges in response to irradiation with radiation; and a transmission unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the conversion unit and a target value. The control device includes: a dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus; an allowable range setting unit configured to set an allowable range of the target dose index value; and a determining unit configured to determine whether the dose index value is within the allowable range. The conversion unit includes a plurality of regions. The signal transmitted by the transmission unit is a signal for providing an instruction to stop irradiation with radiation, the signal being transmitted based on the charge of each of the plurality of regions, the target value, and a stop condition. The dose indicator generating unit is configured to generate a dose indicator value for each of the plurality of regions of the converting unit. The determination unit is configured to determine whether a maximum dose index value among the dose index values of the plurality of regions is within the allowable range, if the stop condition is OR.

A fourth radiation imaging system according to an embodiment of the present invention includes a radiation imaging apparatus and a control apparatus. The radiation imaging apparatus includes: a conversion unit configured to generate electric charges in response to irradiation with radiation; and a transmission unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the conversion unit and a target value. The control device includes: a dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus; an allowable range setting unit configured to set an allowable range of the target dose index value; and a determining unit configured to determine whether the dose index value is within the allowable range. The conversion unit includes a plurality of regions. The signal transmitted by the transmission unit is a signal for providing an instruction to stop irradiation with radiation, the signal being transmitted based on the charge of each of the plurality of regions, the target value, and a stop condition. The dose indicator generating unit is configured to generate a dose indicator value for each of the plurality of regions of the converting unit. The determination unit is configured to determine whether an average value of dose index values of the plurality of regions is within the allowable range, if the stop condition is AVG.

A fifth radiation imaging system according to an embodiment of the present invention includes a radiation imaging apparatus and a control apparatus. The radiation imaging apparatus includes: a conversion unit configured to generate electric charges in response to irradiation with radiation; and a transmission unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the conversion unit and a target value. The control device includes: a dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus; an allowable range setting unit configured to set an allowable range of the target dose index value; a determining unit configured to determine whether a dose index value is within the allowable range; and a display unit configured to display a determination result. The conversion unit includes a plurality of regions. The signal transmitted by the transmission unit is a signal for providing an instruction to stop irradiation with radiation, the signal being transmitted based on the charge of each of the plurality of regions, the target value, and a stop condition. The dose indicator generating unit is configured to generate a dose indicator value for each of the plurality of regions of the converting unit. The determination unit is configured to select at least one region among the plurality of regions based on the stop condition and make a determination as to whether a dose index value of the selected region is within the allowable range. The display unit is configured to display the determination result such that the position of the selected region is distinguishable, in a case where the determination result of the determination indicates that the dose index value of the selected region is outside the allowable range.

Further features of the invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1 is a diagram illustrating a radiation imaging system.

Fig. 2 is a diagram illustrating a radiation imaging apparatus.

Fig. 3 is a diagram illustrating an example of an arrangement of a receptor field (receptor field) and an imaging region.

Fig. 4 is a diagram illustrating an example of an arrangement of an acceptor field and an imaging region.

Fig. 5 is a diagram illustrating an imaging device control unit in the radiation imaging device.

Fig. 6 is a diagram illustrating a control apparatus in the radiation imaging system.

Fig. 7 is a diagram illustrating an example of a flowchart for calculating an EI value.

Fig. 8A to 8D are diagrams illustrating an example of a method for displaying a dose index value.

Fig. 9A to 9C are diagrams illustrating an example of a method for displaying a dose index value.

Fig. 10 is a diagram illustrating an example of a flowchart including a display of a designation of a dose index value to a stop region.

Fig. 11 is a diagram illustrating an example of a method for specifying a dose index value.

Fig. 12 is a diagram illustrating an example of a method for displaying a stop region.

Fig. 13 is a diagram illustrating an example of a method for displaying a ratio outside a threshold value of a stop area.

Fig. 14 is a diagram illustrating an example operation of the radiation imaging system.

Fig. 15A to 15C are diagrams illustrating an example of a method for displaying a dose index value.

Detailed Description

Examples

A radiation imaging system according to an embodiment will be described below with reference to the drawings. Fig. 1 is a diagram illustrating a radiation imaging system according to an embodiment.

As shown in fig. 1, the radiation imaging system 10 is provided in a radiation room 1 for performing radiation imaging using radiation irradiation and a control room 2 located in the vicinity of the radiation room 1.

As the radiation imaging system 10, the radiation room 1 is equipped with a radiation imaging apparatus 300, a stand 302, a radiation imaging apparatus communication cable 307, an Access Point (AP) 320, and a communication control apparatus 323. Further, the radiation room 1 is equipped with a radiation generating device 324, a radiation source 325, an AP communication cable 326, and a radiation generating device communication cable 327.

As the radiation imaging system 10, the control room 2 is equipped with a control device 310, a radiation irradiation switch 311, an input device 313, a display device 314, a hospital Local Area Network (LAN) 315, and a radiation room communication cable 316.

The radiation imaging apparatus 300 includes a power supply control unit 301 constituted by a battery or the like, a wired communication unit 303, and a wireless communication unit 304. The radiation imaging apparatus 300 detects radiation transmitted through the subject 306 and generates radiographic image data.

The wired communication unit 303 enables transmission and reception of information by using, for example, a communication standard having a predetermined protocol or a cable connection of a standard such as ethernet.

The wireless communication unit 304 includes, for example, an antenna and a circuit board including a communication Integrated Circuit (IC) or the like. A circuit board including a communication IC or the like performs communication processing of a protocol based on wireless LAN via an antenna. There is no particular limitation on the frequency band, standard, or method of wireless communication. Short range wireless methods such as Near Field Communication (NFC) or bluetooth, ultra Wideband (UWB), etc. may be used. The wireless communication unit 304 may have a plurality of wireless communication methods, and may perform communication by appropriately selecting a method from among the methods. Hereinafter, the wired communication unit 303 and the wireless communication unit 304 may be collectively referred to as a communication unit, a transmission unit, or a reception unit, and the wired communication unit 303 and the wireless communication unit 304 may be individually referred to as a communication unit, a transmission unit, or a reception unit.

The stand 302 is a stand on which the radiation imaging apparatus 300 can be mounted to capture a radiographic image in a stand position. The radiation imaging apparatus 300 is attachable to the stand 302 and detachable from the stand 302, and is capable of performing imaging both in a state in which the radiation imaging apparatus 300 is attached thereto and in a state in which the radiation imaging apparatus 300 is detached therefrom.

The radiation imaging apparatus communication cable 307 is a cable for connecting the radiation imaging apparatus 300 and the communication control apparatus 323.

The access point 320 performs wireless communication with the radiation imaging apparatus 300. For example, when the radiation imaging apparatus 300 is used while being detached from the stand 302, the access point 320 is used to relay communication between the radiation imaging apparatus 300 and the control apparatus 310 and communication between the radiation imaging apparatus 300 and the radiation generating apparatus 324. Although fig. 1 illustrates an example in which communication is performed via the access point 320, the radiation imaging apparatus 300 or the communication control apparatus 323 may be used as an access point to perform direct communication without using the access point 320.

The communication control means 323 performs control so that the access point 320, the radiation generating means 324, and the control means 310 can communicate with each other.

The radiation generating apparatus 324 controls the radiation source 325 to emit radiation based on predetermined irradiation conditions.

The radiation source 325 irradiates the subject 306 with radiation according to the control of the radiation generating apparatus 324.

The AP communication cable 326 is a cable for connecting the access point 320 and the communication control device 323.

The radiation generating apparatus communication cable 327 is a cable for connecting the radiation generating apparatus 324 and the communication control apparatus 323.

The control device 310 communicates with the radiation generating device 324 and the radiation imaging device 300 via the communication control device 323, and controls the radiation imaging system 10 in a centralized manner.

The radiation irradiation switch 311 inputs the timing of radiation irradiation in response to an operation performed by the operator 312.

The input device 313 is a device that inputs instructions from the operator 312, and may be various types of input devices such as a keyboard or a touch panel.

The display device 314 is a device that displays radiographic image data subjected to image processing and a Graphical User Interface (GUI), and may be a display or the like.

The intra-hospital LAN 315 is a backbone network within the hospital.

The radiation room communication cable 316 is a cable for connecting the control device 310 and the communication control device 323 in the radiation room 1.

Fig. 2 is a diagram illustrating a radiation imaging apparatus 300. As shown in fig. 2, the radiation imaging apparatus 300 includes a radiation detector 100. The radiation detector 100 has a function of detecting radiation for irradiation. Specifically, the radiation detector 100 functions as a conversion unit that generates electric charges in response to irradiation with radiation. The radiation detector 100 (hereinafter also referred to as a conversion unit) includes a plurality of pixels arranged in a plurality of rows and a plurality of columns. In the following description, an area in the radiation detector 100 in which a plurality of pixels are arranged is referred to as a detection area. The plurality of pixels includes an imaging pixel 101 and a correction pixel 121. The imaging pixel 101 is an imaging pixel for acquiring a radiographic image or radiation irradiation information (in the present invention, the imaging pixel will be hereinafter referred to as a detection pixel in order to describe the purpose of acquiring radiation irradiation information). The correction pixel 121 is a correction pixel for removing a dark current component or a crosstalk component.

The detection pixels 101 may be used only for the purpose of acquiring a radiographic image or only for the purpose of acquiring radiation irradiation information. Further, the detection pixel 101 may be used for a selected one of the purpose of acquiring a radiographic image and the purpose of acquiring radiation irradiation information, or may be used for both the purpose of acquiring a radiographic image and the purpose of acquiring radiation irradiation information.

The detection pixel 101 includes a first conversion element 102 that converts radiation into an electric signal, and a first switch 103 disposed between a column signal line 106 and the first conversion element 102.

The first conversion element 102 is constituted by a scintillator that converts radiation into light and a photoelectric conversion element that converts light into an electric signal. In the present embodiment, generating electric charges in response to irradiation with radiation includes converting radiation into light and converting light into an electrical signal. The scintillator is typically formed in a sheet shape so as to cover the detection area, and is shared by a plurality of pixels. Alternatively, the first conversion element 102 is constituted by a conversion element that directly converts radiation into light.

The first switch 103 includes, for example, a Thin Film Transistor (TFT) in which an active region is formed of a semiconductor such as amorphous silicon or polysilicon (polysilicon in one embodiment).

The region in which the detection pixels 101 and the correction pixels 121 for acquiring radiation exposure information are arranged is located at a certain position in the detection region of the radiation imaging apparatus 300. Similar to existing individual AEC sensors, this region may be located in multiple regions, such as regions a-C in fig. 3 or regions K-O in fig. 4, for example.

The radiation imaging apparatus 300 includes a plurality of column signal lines 106 and a plurality of drive lines 104.

Each column signal line 106 corresponds to one of a plurality of columns in the detection area. Each drive line 104 corresponds to one of a plurality of rows in the detection area.

Each drive line 104 is driven by a drive circuit 221.

The first conversion element 102 comprises a first electrode connected to the first main electrode of the first switch 103 and the second conversion element 122 comprises a first electrode connected to the first main electrode of the second switch 123. The first switching element 102 and the second switching element 122 each include a second electrode connected to the bias line 108. One bias line 108 extends in the column direction and is commonly connected to the second electrodes of the plurality of conversion elements 102 and 122 arranged in the column direction.

Bias line 108 receives bias voltage Vs from element power supply circuit 226. The bias voltage Vs is supplied from the element power supply circuit 226.

The first switches 103 of the plurality of detection pixels 101 and the second switches 123 of the plurality of correction pixels 121 in one column include respective second main electrodes connected to one of the plurality of column signal lines 106. The first switches 103 of the plurality of detection pixels 101 and the second switches 123 of the plurality of correction pixels 121 in one row include respective control electrodes connected to one of the plurality of drive lines 104. The plurality of column signal lines 106 are connected to the read circuit 222. The reading circuit 222 includes a plurality of detection units 132, a multiplexer 134, and an analog-to-digital converter (hereinafter, an AD converter) 136.

Each of the plurality of column signal lines 106 is connected to a corresponding one of the plurality of detection cells 132 of the read circuit 222. Here, one column signal line 106 corresponds to one detection unit 132.

The detection unit 132 includes, for example, a differential amplifier. The multiplexer 134 selects the plurality of detection units 132 in a predetermined order, and supplies signals from the selected detection units 132 to the AD converter 136.

The AD converter 136 converts a signal supplied thereto into a digital signal and outputs the digital signal.

The signal processing unit 224 outputs information indicating irradiation of the radiation imaging apparatus 300 with radiation based on the output of the reading circuit 222 (AD converter 136). Specifically, the signal processing unit 224 performs, for example, characteristic correction processing of removing a dark current component or a crosstalk component of the radiation imaging apparatus 300 using correction pixels, detection of irradiation with radiation, calculation of the amount of irradiation with radiation, and calculation of the integrated amount of irradiation, and the like.

The imaging device control unit 225 controls the driving circuit 221, the reading circuit 222, and the like according to information from the signal processing unit 224 or a control command from the control device 310.

Fig. 5 is a diagram illustrating the imaging device control unit 225 of the radiation imaging device 300. As shown in fig. 5, the imaging device control unit 225 includes a drive control unit 400, a Central Processing Unit (CPU) 401, a memory 402, a radiation generating device control unit 403, an image data control unit 404, and a communication switching unit 405.

The drive control unit 400 controls the drive circuit 221 and the read circuit 222 according to information from the signal processing unit 224 or a command from the control device 310.

The CPU 401 controls the entire radiation imaging apparatus 300 by using programs and various data stored in the memory 402.

The memory 402 stores, for example, a program to be used by the CPU 401 to execute processing and various data. The various data include various data obtained by processing performed by the CPU 401 and radiographic image data.

The radiation generating apparatus control unit 403 controls communication with the radiation generating apparatus 324 according to information from the signal processing unit 224 or information from the drive control unit 400.

The radiation generating apparatus control unit 403 and the radiation generating apparatus 324 transmit and receive information about the control of the radiation generating apparatus 324 (for example, notification of start of irradiation with radiation or stop of irradiation with radiation, amount of irradiation with radiation, integrated amount of irradiation with radiation, and the like).

In response to the radiation dose in the radiation detection area (acceptor field) for monitoring radiation reaching the reference threshold as the target value, the radiation generating apparatus control unit 403 supplies a stop notification as information on control of the radiation generating apparatus 324 to the radiation generating apparatus 324. The radiation generating apparatus control unit 403 may provide a stop notification to the control apparatus 310 instead of the radiation generating apparatus 324. In the case where the stop notification is supplied to the control device 310, the stop notification is supplied from the control device 310 to the radiation generating device 324, and the radiation irradiation is stopped. The radiation generating apparatus control unit 403 may provide a stop notification to the radiation generating apparatus 324 and may notify only the control apparatus 310 whether the stop notification has been provided. In this way, the stop notification is supplied from the radiation imaging apparatus 300 to the external apparatus in any of these various notification modes. The notification is not limited to the stop notification, and various notifications related to the control of radiation irradiation (such as the start of irradiation, the amount of irradiation, and the integrated amount of irradiation) may be provided as described above. The acceptor fields correspond to, for example, regions a to C in fig. 3 and regions K to O in fig. 4. In the case where such a plurality of acceptor fields are provided, the radiation detector 100 serving as a conversion unit includes a plurality of regions. As a result of setting such a plurality of receptor fields, information on radiation can be acquired for each receptor field.

The radiation generating apparatus control unit 403 provides a stop notification (hereinafter referred to as reaching dose monitoring function) in response to the radiation dose in the receptor field selected as the target to be monitored reaching a reference threshold as the target value. In the case where a plurality of receptor fields are selected as targets to be monitored, for example, a stop notification may be provided in response to the radiation dose in any one of the selected receptor fields reaching a reference threshold. In this case, the stop condition is an OR condition, which will be described in detail below. Alternatively, the stop notification may be provided in response to the radiation doses in all selected receptor fields reaching a reference threshold. In this case, the stop condition is an AND condition. The mode in which the radiation generating apparatus control unit 403 provides the stop notification is set by, for example, any one of the radiation imaging apparatus 300, the radiation generating apparatus 324, and the control apparatus 310. A mode in which radiation irradiation is not stopped according to the reached radiation dose can be provided. A system may be provided in which a general-purpose exposure control sensor (ionization chamber/photo timer, etc.), not shown, is attached to the outside of the radiation imaging apparatus 300 and radiation irradiation is stopped according to the radiation dose. In the present embodiment, a radiation generating apparatus control unit 403 is provided. Alternatively, radiation irradiation may be detected by the signal processing unit 224 without communicating with the radiation generating apparatus 324 to perform radiation imaging.

The image data control unit 404 stores image data from the reading circuit 222 in the memory 402, and controls communication with the control device 310. The image data control unit 404 and the control device 310 transmit and receive radiographic image data and information about control (e.g., control commands, etc.).

The communication switching unit 405 enables communication by the wired communication unit 303 in response to the radiation imaging apparatus communication cable 307 being connected to the radiation imaging apparatus 300. The communication switching unit 405 switches the communication unit in response to the disconnection of the radiation imaging apparatus communication cable 307 from the radiation imaging apparatus 300 so as to enable communication by the wireless communication unit 304.

Fig. 6 is a diagram illustrating the control device 310. As shown in fig. 6, the control device 310 includes a dose index region determination unit 501, a dose index generation unit 502, a dose index display unit 503, a dose index specification unit 504, a dose index ratio calculation unit 505, an unexpected stop report unit 506, and a stop region display unit 507. The dose index ratio calculation unit 505 has a function of setting an allowable range of a target dose index value to be described below, and thus may be referred to as an allowable range setting unit in the following description. The dose index ratio calculation unit 505 also has a function of determining whether or not the dose index value is within the set allowable range, and thus may be referred to as a determination unit.

The dose index region determination unit 501 determines a region in a radiographic image generated by the radiation imaging apparatus 300 where a dose index value is to be calculated. The number of regions may be one, or two or more. In the present embodiment, the region is rectangular, but the shape is not limited thereto. The dose index value is, for example, an Exposure Index (EI) value. In the present embodiment, the EI value is used as the dose index value, but a similar technique can be applied to any other dose index value.

The dose index generation unit 502 calculates a dose index value of the region determined by the dose index region determination unit 501. A target dose index (e.g., target exposure index (EIt)) that can be determined to be an optimal dose may be set for each region, and a deviation index (e.g., DI) may be calculated. Specifically, for example, a dose index value is generated based on radiographic image information obtained from the electrical signals generated by the conversion element 102. The target dose index value may be generated based on a target value (reference threshold value) of the radiation dose for determining an instruction to transmit the radiation stop signal by the radiation generating apparatus control unit 403.

The dose index display unit 503 displays the dose index value, the target dose index, and the deviation index generated by the dose index generation unit 502. The number of contents to be displayed may be one, or two or more. The display method may be changed according to the imaging conditions. In the present embodiment, the dose index region determination unit 501 and the dose index generation unit 502 are included in the control device 310. Alternatively, these units may be included in the radiation imaging apparatus 300.

Fig. 7 illustrates a flowchart of the dose index generation unit 502 calculating the EI value from the image.

First, in S710, a region that is significantly outside the region of interest of the diagnostic image, which is not irradiated with X-rays, is excluded from the EI value calculation region in the captured image. Examples of the method to be used include a method of performing calculation based on collimator information or tube-FPD distance (FDD) information, a method of extracting an irradiation region from an image by using imaging region information obtained in advance, and a method of AI determination using machine learning.

Next, in S720, a direct radiation region is specified, and a region outside the region of interest is excluded from the EI value calculation region. Examples of methods include an empirical fixed threshold method, a mode method, a differential histogram method, a p-tile method, and a discriminant analysis method.

Further, in S730, a low dose region that is within the region of interest but will not be used as a dose index of the region of interest in a normal diagnostic image is excluded from the EI value calculation region. Examples of the method include a region growing method and a snake method. The foregoing process is applied to the region for calculating the dose index value predetermined by the dose index region determination unit 501 or to the entire image, and then the region for calculating the dose index value determined by the dose index region determination unit 501 is cut out to determine the region for calculating the EI value. The exclusion of the outside of the area of the irradiation area, the exclusion of the direct radiation area, and the exclusion of the unnecessary area such as metal may be selectively performed or may not be performed.

Next, in S740, a representative value such as an average value or a median value is calculated.

Finally, in S750, the representative value is converted into an EI value such that 100=1μgy holds.

At the same time, the deviation DI from EIt is calculated and the operator determines whether the capturing of the X-ray image has been performed at the desired X-ray dose.

The dose index display unit 503 displays the dose index value generated by the dose index generation unit 502 on the display device 314. The dose index value may be displayed as an annotation at the end of the radiographic image as shown in fig. 8A, or may be displayed as superimposed on the image area for which the dose index value is calculated as shown in fig. 8B. Further, the dose index value may be displayed separately from the radiographic image as shown in fig. 8C, or may not be displayed together with the radiographic image as shown in fig. 8D. Alternatively, as shown in fig. 9A, the dose index value may be displayed on the radiographic image in gray scale (or chromaticity), or as shown in fig. 9B, only the gray scale (or chromaticity) may be displayed separately. Of course, a combination may be used as shown in fig. 9C.

Fig. 8A to 8D and fig. 9A to 9C illustrate examples of a method of displaying a dose index value by using characters, colors, or the like. The display method is defined by any combination of recognizable expressions such as characters, symbols, graphics, sizes, colors, and shapes. Further, the dose index display unit 503 may display the target dose index and the deviation index value together with the dose index value. The target dose index and the deviation index may be displayed by the same display method as the display method for the dose index value, or may be displayed by any different display method. Instead of displaying the dose index value or the deviation index value, for example, a warning dialog may be displayed when the dose index value or the deviation index value is equal to or greater than a predetermined threshold value. The number of thresholds may be one or a threshold may be provided for each region for which a dose index value is calculated.

The dose index specification unit 504, the dose index ratio calculation unit 505, the unexpected stop report unit 506, and the stop region display unit 507 will be described with reference to fig. 10. A description will be given of a process of specifying the comparison dose, calculating the ratio to the target dose index, reporting an abnormal stop of AEC if the ratio is out of the range of normal values, and displaying the stop region, which are performed by these units.

First, in S1010, the dose index specification unit 504 specifies an area that has caused the imaging unit to transmit an irradiation stop signal based on the dose index value generated by the dose index generation unit 502 AND the stop condition (AND, OR AVG) set in the radiation imaging apparatus 300. If the irradiation ends before the AEC operation and there is no region that has caused the imaging unit to transmit the irradiation stop signal, the specification of the region need not be performed. In the present embodiment, the stop condition is acquired from the header information of the captured image. Alternatively, for example, the information may be received separately from the radiation imaging apparatus 300 by communication.

As shown in fig. 11, dose index values of the region a, the region B, and the region C are calculated. In the case where the stop condition is AND, the minimum value among the dose index values of the region a, the region B, AND the region C is designated as the dose index value. In the case where the stop condition is OR, the maximum value is designated as the dose index value. In the case where the stop condition is AVG, the average value of the dose index values of the region a, the region B, and the region C is designated as the dose index value.

Next, in S1020, the dose index ratio calculating unit 505 calculates the ratio of the dose index value of the region specified by the dose index specifying unit 504 to the target dose index. Subsequently, it is determined whether the calculated ratio is within a range of normal values, i.e., whether the calculated ratio is within an allowable range. If the calculated ratio is outside the range, the unexpected-stop reporting unit 506 reports the determination result. In the present embodiment, the ratio is calculated and it is determined whether the ratio is within the allowable range. This means that an allowable range is set for the target dose index value and it is determined whether the dose index value is within the allowable range. That is, the determination of whether the relation between the target dose index value and the dose index value satisfies the setting condition is also included in the setting of the allowable range of the target dose index value and the determination of whether the dose index value is within the allowable range. Therefore, the dose index ratio calculation unit 505 may be regarded as an allowable range setting unit that sets an allowable range of the target dose index value or a determination unit that determines whether the dose index value is within the allowable range. As described above, the dose index ratio calculation unit 505 calculates the ratio of the dose index value of the region specified by the dose index specification unit 504 to the target dose index, and thus the dose index specification unit 504 has a part of the function of the determination unit. As described above, the dose index specification unit 504 has a function of selecting a predetermined region among a plurality of regions based on the stop condition.

If the dose index specification unit 504 does not specify an area, calculation of the ratio is not performed. In the present embodiment, the target dose index is calculated based on information about a radiation stop target value stored in the head of the captured image, but the present invention is not limited thereto. In the present embodiment, the ratio of the dose index value to the target dose index value is calculated, but the calculation method is not limited thereto. For example, the deviation DI may be obtained.

Subsequently, if the ratio calculated by the dose index ratio calculation unit 505 is outside the range of normal values, the unexpected-stop reporting unit 506 reports according to the values (S1030, S1040). For example, the content of the report may differ between a case where the value is above an upper threshold and a case where the value is below a lower threshold. If the dose index specification unit 504 does not perform specification of the region, a report indicating that irradiation ends before the AEC operation may be made. Alternatively, in response to the radiation generating apparatus control unit 403 not providing the stop notification to the radiation generating apparatus 324, a report indicating that the irradiation ends before the AEC operation may be made. If the ratio calculated by the dose index ratio calculation unit 505 is within the range of normal values, the process ends (S1060).

The content of the report may be different between a case where communication between the radiation imaging apparatus 300 and the control apparatus 310 is wired communication and a case where communication therebetween is wireless communication.

Finally, in S1050, if the ratio calculated by the dose index ratio calculation unit 505 is outside the range of normal values, the stop region display unit 507 displays a region that has caused the irradiation stop signal to be transmitted. That is, at least one region is selected from among the plurality of regions according to the stop condition. If the dose index value of the selected region is outside the allowable range, the determination result is displayed such that the position of the selected region can be recognized. This will be described with reference to fig. 12.

As shown in fig. 12, in the present embodiment, the receptor fields and the dose index values of the corresponding receptor fields are displayed according to the relative positions in the image, and the region that has caused the irradiation stop signal to be transmitted is displayed separately from the other receptor fields. As shown in part (a) of fig. 12, in the case where the stop condition is AND, the region having the smallest dose index value among the region a, the region B, AND the region C is displayed in a color different from that of the other regions. As shown in part (b) of fig. 12, in the case where the stop condition is OR, the region having the maximum dose index value is displayed in a color different from that of the other regions. As shown in part (C) of fig. 12, in the case where the stop condition is AVG, the region a, the region B, and the region C are displayed in the same color. In the case where the stop condition is AND, all the regions may be displayed in the same color to clearly indicate that the dose index value of all the regions is greater than or equal to the target dose index value. In the case where the stop condition is AVG, only the region having the dose index value greater than or equal to the target dose index value may be displayed in the same color so as to be distinguished from the region having the dose index value less than the target dose index value. As shown in part (d) of fig. 12, in the case where the dose index specification unit 504 does not specify an area, all the receptor fields may be displayed without being distinguished from each other.

In fig. 12, the dose index value of each region of interest is indicated by a numerical value, and the stop region is displayed in a color different from that of the other regions. However, the display method is not limited thereto, and is defined by any combination of recognizable expressions such as characters, symbols, graphics, sizes, colors, and shapes.

Alternatively, as shown in fig. 13, the displayed content may vary depending on whether the ratio of the areas that have caused the irradiation stop signal to be transmitted is below the lower limit threshold or above the upper limit threshold. The displayed content may be expressed by characters as shown in part (a) of fig. 13, or may be expressed using colors as shown in part (b) of fig. 13. In this way, the user can know whether the X-ray is weaker or stronger than desired by merely checking the displayed content, and can use the displayed content as a stand point for viewing the environment and setting. In fig. 13, whether the ratio is higher than the upper threshold or lower than the lower threshold is expressed by characters and colors. However, the expression method is not limited thereto, and is defined by any combination of identifiable expressions such as numerical values, symbols, graphics, sizes, colors, and shapes.

Next, an imaging operation of the radiation imaging system 10 will be described with reference to fig. 14.

When the power of the radiation imaging system 10 is turned on and the power of the radiation imaging apparatus 300 is turned on, initial setting is performed and communication with the control apparatus 310 is enabled.

In step S101, the radiation imaging system 10 sets subject information such as the ID, name, and date of birth of the subject 306 in the control device 310. In step S102, the radiation imaging system 10 sets imaging information such as an imaging region of the subject 306, a receptor field, and a target dose index. The subject information and imaging information can be automatically set by, for example, selecting an examination order received via the in-hospital LAN 315. The imaging information may be set by selecting a preset imaging scheme.

At this time, the operator 312 can directly input and set information of the subject 306 and imaging information.

The radiation imaging system 10 sets the receptor field of the radiation imaging apparatus 300 based on the input information. After the information of the subject 306 and the information of the imaging region have been set in the control apparatus 310, the operator 312 fixes the posture of the subject 306 and the radiation imaging apparatus 300. Further, the operator 312 inputs a dose, a maximum irradiation time, a tube current, a tube voltage, region information, a receptor field, a target dose index, and the like to the control device 310. The control device 310 transmits the radiation irradiation conditions, the region information, the acceptor field, the target dose index, and the like, which have been input, to the radiation imaging device 300 and the radiation generating device 324. In the system, information may be input to the radiation generating apparatus 324, and information may be provided to the control apparatus 310 and the radiation imaging apparatus 300.

After the preparation for imaging has been completed, the operator 312 presses the radiation irradiation switch 311 in step S103. When the radiation irradiation switch 311 is pressed, radiation is emitted from the radiation source 325 toward the subject 306. At this time, the radiation imaging apparatus 300 communicates with the radiation generating apparatus 324 to control the start of radiation irradiation. The radiation applied to the subject 306 is transmitted through the subject 306 and enters the radiation imaging apparatus 300. In the case where the setting has been made so as to use the reaching dose monitoring function, the radiation imaging apparatus 300 detects the radiation that has entered the receptor field with the detection pixels 101, and calculates the integrated amount of irradiation, which is the integrated value of the dose (reaching dose) detected in a predetermined period, with the signal processing unit 224. The imaging device control unit 225 calculates a reference threshold value from the information on the integrated amount of irradiation received from the signal processing unit 224, the region information input by the operator 312, the imaging conditions, and the like, and determines the radiation irradiation stop timing according to the mode set in the radiation generating device control unit 403. In accordance with the determined radiation exposure stop timing, the radiation imaging apparatus 300 supplies a stop notification to the radiation generating apparatus 324 via the radiation imaging apparatus communication cable 307, the communication control apparatus 323, and the radiation generating apparatus communication cable 327. The radiation generating apparatus 324 stops radiation irradiation according to the notified radiation irradiation stop timing. The radiation imaging apparatus 300 provides notification of stopping radiation irradiation as a result of detecting radiation, but the present invention is not limited thereto. The radiation imaging apparatus 300 may transmit the reached dose at predetermined time intervals as a detection result, and the radiation generating apparatus 324 may calculate an integrated value of the reached dose. After the radiation irradiation has stopped, the radiation imaging apparatus 300 converts the incident radiation into visible light, and then detects the visible light as a radiographic image signal by the photoelectric conversion element. The radiation imaging apparatus 300 drives the photoelectric conversion element to read out a radiographic image signal, and converts an analog signal into a digital signal by an AD conversion circuit to obtain digital radiographic image data.

In step S104, the obtained digital radiographic image data is transmitted from the radiation imaging apparatus 300 to the control apparatus 310 via the radiation imaging apparatus communication cable 307, the communication control apparatus 323, and the radiation room communication cable 316. The control device 310 performs image processing on the received digital radiographic image data. The control device 310 causes the display device 314 to display a radiographic image based on the radiographic image data subjected to the image processing. The control device 310 also functions as an image processing device and a display control device.

In step S105, the receptor field is determined as the calculation region.

In step S106, the control device 310 transmits the received digital radiographic image data to the dose index generation unit 502. By using the received radiographic image data, the dose index generation unit 502 calculates a dose index value of the determined calculation region, and then calculates a deviation index value in step S107. In the present embodiment, the dose index value and the deviation index value are calculated by the control device 310. However, the calculation may be performed by the radiation imaging apparatus 300 or another component.

In step S108, the dose index value and the deviation index value calculated by the dose index generation unit 502 are transmitted to the dose index display unit 503 and displayed in the manner shown in fig. 15A to 15C, for example. Referring to fig. 15A to 15C, imaging is performed on a lung field region where the dose monitoring function is enabled. Imaging is performed in which the two lung regions R1 and R2 shown in fig. 15B are receptor fields. As shown in fig. 15A and 15C, as a result of displaying the dose index value and the deviation index value for each region, it can be determined whether the dose for the receptor field set as the region of interest is appropriate. The region of interest is not limited to the receptor field reaching the dose monitoring function and any region may be set, or the operator 312 may change the region of interest after imaging. The setting as to whether or not to perform the display on the display device 314 may be performed before imaging, or may be performed by the operator 312 after imaging. The display settings may be changed by reaching the settings of the dose monitoring function. Alternatively, if the received dose index value or deviation index value satisfies a specific condition, control may be performed to display an icon or dialog box (not shown). The specific condition may be, for example, a case where the dose index value or the deviation index value is greater than a predetermined value.

In step S109, an area that has caused the radiation imaging apparatus 300 to transmit the irradiation stop signal is specified based on the dose index value calculated by the dose index generating unit 502 AND the stop condition (AND, OR AVG) set in the radiation imaging apparatus 300. The stop condition is acquired from the header information of the captured image, but is not limited thereto. At this time, if the irradiation ends before the AEC operation and there is no region that has caused the imaging unit to transmit the irradiation stop signal, the specification of the region need not be performed.

In step S110, the ratio of the dose index value specified in step S109 to the target dose index value is calculated. If the ratio is outside the range of normal values, a report is made in step S111, and an area that has caused the irradiation stop signal to be transmitted is displayed in step S112. If no area is specified in step S109, step S110 is skipped and reporting is performed in step S111.

As a result of constructing the above system, if AEC is not stopped at normal timing in AEC imaging, the operator 312 can immediately notice an environmental defect or a setting error by checking the contents of the report and the displayed area.

For example, if more X-rays than desired are detected in the wireless communication environment and if a report for prompting the operator 312 to check the communication state is made, the operator 312 can notice that imaging is being performed in an unstable wireless communication environment. Further, if less X-rays than desired are detected and if a report is made prompting the operator 312 to determine whether the X-ray tube is properly positioned, the operator 312 can determine the positioning of the X-ray tube and the area where the irradiation stop signal has been caused to be transmitted. As a result, the operator 312 can notice that the positioning of the X-ray tube is not proper. Further, as a result of reporting that irradiation ends before the AEC operation, the user can notice that he/she releases the radiation irradiation switch early.

The embodiments may also be implemented by a computer or by a control computer executing a program (computer program). Further, means for supplying the program to a computer (for example, a computer-readable recording medium such as a CD-ROM storing the program, or a transmission medium such as the internet for transmitting the program) may also be applied as an embodiment. The above procedure can also be applied as an example. The above-described program, recording medium, transmission medium, and program product are included in the scope of the present invention.

The embodiments have been described in detail. The present invention is not limited to a specific embodiment, and for example, the present invention is applicable not only to capturing of still images but also to capturing of moving images. Various modes within the scope not departing from the gist of the present invention are also included in the scope of the present invention. Further, the above-described embodiment is only one embodiment, and the invention easily conceivable from the above-described embodiment is also included in the scope of the present invention.

According to one or more embodiments of the invention, it may be determined whether the AEC is operating correctly.

OTHER EMBODIMENTS

Embodiments of the present invention may also be implemented by a computer that reads out 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 embodiments and/or a system or apparatus including one or more circuits (e.g., application Specific Integrated Circuits (ASICs)) for performing the functions of one or more of the above-described embodiments, and by a method performed by a computer of the system or apparatus by, for example, reading out and executing computer-executable instructions from the storage medium to perform the functions of one or more of the above-described embodiments and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiments. The computer may include one or more processors (e.g., a Central Processing Unit (CPU), a Micro Processing Unit (MPU)), and may include a separate computer or a network of separate processors to read out and execute the computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, one or more of a hard disk, random Access Memory (RAM), read Only Memory (ROM), a storage device for a distributed computing system, an optical disk such as a Compact Disk (CD), digital Versatile Disk (DVD), or blu-ray disc (BD) ^TM, a flash memory device, a memory card, etc.

The embodiments of the present invention can also be realized by a method in which software (program) that performs the functions of the above embodiments is supplied to a system or apparatus, a computer of the system or apparatus or a method in which a Central Processing Unit (CPU), a Micro Processing Unit (MPU), or the like reads out and executes the program, through a network or various storage mediums.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A radiation imaging system comprising:

a radiation imaging apparatus includes

A conversion unit configured to generate electric charges in response to irradiation with radiation, an

A transmitting unit configured to transmit a signal related to control of irradiation with radiation to an external device based on the charge generated by the converting unit and a target value; and

A control device comprises

A dose index generation unit configured to generate a target dose index value based on the target value and a dose index value based on information on electric charges acquired from the radiation imaging apparatus,

An allowable range setting unit configured to set an allowable range of the target dose index value, and

And a determining unit configured to determine whether the dose index value is within the allowable range.

2. The radiation imaging system according to claim 1, wherein the allowable range setting unit is configured to set the allowable range based on a ratio of a dose index value to a target dose index value.

3. The radiation imaging system according to claim 2, wherein the control device further comprises a reporting unit configured to report the determination result in a case where the determination result of the determination unit indicates that the dose index value is out of the allowable range.

4. A radiation imaging system according to claim 3, wherein the reporting unit includes a display unit.

5. A radiation imaging system according to claim 3, wherein the content of the report by said reporting unit differs between a case where the determination result of said determining unit indicates that the dose index value is higher than the upper limit of said allowable range and a case where the determination result of said determining unit indicates that the dose index value is lower than the lower limit of said allowable range.

6. The radiation imaging system according to claim 3, wherein

The radiation imaging apparatus is capable of transmitting the signal related to control of irradiation with radiation to the external apparatus by wired communication or wireless communication, and

The content of the report by the reporting unit differs between the case where the signal is transmitted by wired communication and the case where the signal is transmitted by wireless communication.

7. The radiation imaging system according to claim 3, wherein

The transmission unit is capable of notifying the control device whether the signal related to control of irradiation with radiation has been transmitted to the external device, and

The content of the report by the reporting unit is different between a case where the transmitting unit has transmitted the signal to the external device and a case where the transmitting unit has not transmitted the signal to the external device.

8. A radiation imaging system comprising:

a radiation imaging apparatus includes

A control device comprises

A determining unit configured to determine whether a dose index value is within the allowable range, wherein

The conversion unit comprises a plurality of regions,

The signal transmitted by the transmission unit is a signal for providing an instruction to stop irradiation with radiation, the signal being transmitted based on the charge of each of the plurality of regions, the target value, and a stop condition,

The dose index generating unit is configured to generate a dose index value for each of the plurality of regions of the converting unit, and

The determination unit is configured to determine whether a minimum dose index value among the dose index values of the plurality of regions is within the allowable range, if the stop condition is an AND.

9. A radiation imaging system comprising:

a radiation imaging apparatus includes

A control device comprises

The conversion unit comprises a plurality of regions,

The determination unit is configured to determine whether a maximum dose index value among the dose index values of the plurality of regions is within the allowable range, if the stop condition is OR.

10. A radiation imaging system comprising:

a radiation imaging apparatus includes

A control device comprises

The conversion unit comprises a plurality of regions,

The determination unit is configured to determine whether an average value of dose index values of the plurality of regions is within the allowable range, if the stop condition is AVG.

11. The radiation imaging system according to claim 8, wherein the allowable range setting unit is configured to set the allowable range based on a ratio of a dose index value to a target dose index value.

12. A radiation imaging system comprising:

a radiation imaging apparatus includes

A control device comprises

An allowable range setting unit configured to set an allowable range of the target dose index value,

A determining unit configured to determine whether the dose index value is within the allowable range, an

A display unit configured to display a determination result, wherein

The conversion unit comprises a plurality of regions,

The dose indicator generating unit is configured to generate a dose indicator value for each of the plurality of regions of the converting unit,

The determination unit is configured to select at least one region among the plurality of regions based on the stop condition and make a determination as to whether a dose index value of the selected region is within the allowable range, and

The display unit is configured to display the determination result such that the position of the selected region is distinguishable, in a case where the determination result of the determination indicates that the dose index value of the selected region is outside the allowable range.

13. The radiation imaging system according to claim 12, wherein the allowable range setting unit is configured to set the allowable range based on a ratio of a dose index value to a target dose index value.

14. The radiation imaging system according to claim 13, wherein the display unit is configured to display the determination result according to a size of the ratio of the determination result.