JP2024056996A - Radiography System - Google Patents

Abstract

[Problem] To reliably prevent the risk of starting imaging with a frame rate set that is not compatible with at least one of the radiographic imaging device and the radiation generating device when imaging is performed in which the radiation generating device irradiates radiation fewer times than a predetermined number of times while the radiographic imaging device repeats accumulation and readout of electric charges a predetermined number of times. [Solution] The system includes a first acquisition means capable of acquiring an irradiation frame rate, a second acquisition means capable of acquiring an imaging frame rate, a determination means for determining whether the irradiation frame rate acquired by the first acquisition means is N times (where N is an integer equal to or greater than 1) the imaging frame rate acquired by the second acquisition means, and a notification means for notifying the photographer of the determination result determined by the determination means in a manner that is recognizable by the photographer, or an output means for outputting the determination result. [Selected Figure] Fig. 9

Description

The present invention relates to a radiography control device, a radiography system, and a radiography method.

In recent years, radiation imaging systems have been developed that include a radiation generating device capable of generating radiation and a radiation image capturing device capable of generating a radiation image based on the received radiation, and that are capable of capturing dynamic images in which each frame is a series of a plurality of radiation images. The systems are capable of capturing dynamic images by switching from a plurality of different frame rates to a desired frame rate.
For example, Patent Literature 1 describes a technology in which a radiation generating device irradiates radiation less than a predetermined number of times (thinning out some of the radiation) while a radiographic imaging device repeats accumulation and readout of electric charges a predetermined number of times, thereby performing imaging with a frame rate lower than normal. Patent Literature 1 also describes that a control unit controls radiation irradiation and accumulation/readout, and corrects and uses thinned images generated at times when radiation was not irradiated.

JP 2005-287773 A

Among radiation imaging systems, there are some that can use a plurality of cassette-type radiation image capturing devices depending on various situations. In such a system, when an attempt is made to switch the frame rate depending on the situation as described in Patent Document 1, problems that do not occur when imaging is performed using a fluoroscopic device in which the combination of a radiation generating means and an image capturing means is fixed may occur, for example, in which imaging cannot be performed because the frame rate specified by the photographer is not compatible with at least one of the radiation image capturing device and the radiation generating means to be used.
In particular, if a situation arises in which the frame rate specified by the photographer is compatible with the radiation generating device but not with the radiation image capturing device, there is a risk that the subject will be unnecessarily exposed to radiation even though the radiation generating device irradiates radiation during imaging, because the radiation image capturing device cannot store and read out the radiation at that timing.

The present invention has been made in consideration of the above points, and aims to reliably prevent the risk of imaging being started with a frame rate set that is not compatible with at least one of the radiographic imaging device and the radiation generating device when imaging is performed by irradiating radiation fewer than a predetermined number of times while the radiographic imaging device repeats accumulation and reading of electric charge a predetermined number of times.

In order to solve the above problems, the radiation imaging control device according to the present invention comprises:
a first acquisition means for acquiring an irradiation frame rate, which is the number of times that a radiation generating device capable of repeatedly generating radiation at a predetermined cycle generates radiation per unit time;
a second acquisition means capable of acquiring an imaging frame rate, which is the number of times that a radiation image capturing device capable of repeatedly generating radiation images based on received radiation at a predetermined cycle generates a radiation image per unit time;
a determination means for determining whether the irradiation frame rate acquired by the first acquisition means is N times (where N is an integer equal to or greater than 1) the imaging frame rate acquired by the second acquisition means;
The present invention is characterized in that it comprises a notification means for notifying the photographer of the result of the determination made by the determination means in a manner that is recognizable by the photographer, or an output means for outputting the result of the determination.

According to the present invention, when a radiation image capturing device repeats charge accumulation and readout a predetermined number of times while a radiation generating device captures radiation fewer than a predetermined number of times, it is possible to reliably prevent the risk of capturing images starting with a frame rate that is not compatible with at least one of the radiation image capturing device and the radiation generating device.

FIG. 1 is a block diagram showing a radiation imaging system according to prior art 1. 1 is a block diagram of a radiation imaging system according to a first embodiment of the present invention. 3 is a block diagram of a radiation image capturing device included in the radiation imaging system of FIG. 2. 3 is a ladder chart showing an initial stage of the operation of the radiation imaging system of FIG. 2 . 3 is a ladder chart showing the middle stage of the operation of the radiation imaging system of FIG. 2. 3 is a ladder chart showing a later stage of the operation of the radiation imaging system of FIG. 2 . 3 is a table showing the correspondence between radiation image capturing devices and radiation generating devices connectable to the radiation imaging system of FIG. 2 and the frame rates compatible therewith. 3 is an example of a display screen of a display unit of a console included in the radiation imaging system of FIG. 2 . 3 is an example of a display screen of a display unit of a console included in the radiation imaging system of FIG. 2 . 3 is an example of a display screen of a display unit of a console included in the radiation imaging system of FIG. 2 . 3 is a timing chart showing the operation of the radiation imaging system of FIG. 2 . FIG. 11 is a block diagram showing a radiation imaging system according to prior art 2. FIG. 11 is a block diagram illustrating a radiation imaging system according to a second embodiment of the present invention. 14 is a ladder chart showing an initial stage of the operation of the radiation imaging system of FIG. 13 . 14 is a ladder chart showing the middle stage of the operation of the radiation imaging system of FIG. 13. 13 is a ladder chart showing the latter stage of the operation of the radiation imaging system. 14 is a state transition diagram for explaining state transition of the radiation imaging system of FIG. 2 or FIG. 13. 14 is a timing chart showing the operation of the radiation imaging system of FIG. 2 or FIG. 13. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 4 is a timing chart showing the operation of the radiation imaging system according to the examples of the first and second embodiments. 1A to 1C are schematic diagrams illustrating an imaging method using a radiation imaging system according to an embodiment of the first and second embodiments. 11 is a table showing steady-state values after recursive processing is performed on dynamic images captured using the radiation imaging systems according to the first and second embodiments. 1 is a block diagram showing an example of the configuration of a radiation imaging system according to the first and second embodiments, the system including a plurality of constituent devices;

Hereinafter, embodiments of the present invention and the related art on which they are based will be described with reference to the drawings. However, the technical scope of the present invention is not limited to the description of the embodiments below or the examples shown in the drawings.
In this embodiment, the following will be described in the order of conventional technique 1 on which the first embodiment is based, the first embodiment, conventional technique 2 on which the second embodiment is based, and the second embodiment.

<Prior Art 1>
First, a conventional technique 1 on which a system 100 (described in detail later) according to a first embodiment of the present invention is based will be described with reference to FIG.

[System configuration]
First, a schematic configuration of a radiation imaging system according to Prior Art 1 (hereinafter, referred to as a conventional system 100A) will be described. Fig. 1 is a block diagram showing the conventional system 100A.

As shown in FIG. 1 , for example, the conventional system 100A includes a radiation control unit 11, a high voltage generating unit 12, a radiation generating unit 2, a cassette 3A, a radiation control console 41, and an irradiation instruction switch 5, and is configured to be capable of capturing still images in which the timing of radiation irradiation and the timing of shooting are not linked, such as with a radiographic film or CR.
Note that Figure 1 illustrates an example in which the radiation control unit 11 and the high voltage generating unit 12 together constitute the radiation control device 1 (for example, stored in a single housing), but the radiation control unit 11 and the high voltage generating unit 12 can also be configured independently, for example, by being arranged in different housings.
The radiation control unit 11, the high voltage generating unit 12 and the radiation generating unit 2 constitute a radiation generating apparatus (hereinafter referred to as a generating apparatus) in the present invention.

The radiation control unit 11 is for controlling radiation irradiation.
Specifically, based on detecting that the irradiation preparation signal from the radiation control console 41 has been turned ON, the radiation control unit 11 is able to turn ON the irradiation preparation signal to be output to the high voltage generating unit 12 or to make it available for output to other external devices.
Furthermore, based on detecting that an irradiation instruction signal (first signal in the present invention) instructing the irradiation of radiation from the radiation control console 41 has been turned ON, the radiation control unit 11 is capable of making this irradiation instruction signal available for output to an external device, and is also capable of transmitting an irradiation signal according to the shooting conditions set by the radiation control console 41 to the high voltage generating unit 12.

The irradiation preparation signal and the irradiation instruction signal that can be output from the radiation control unit 11 to an external device are used, for example, when an external device is connected to the radiation control unit 11 .
These irradiation preparation signals and irradiation instruction signals enable the external equipment to prepare for imaging based on the irradiation preparation signal and irradiation instruction signal output from the radiation control unit 11 when imaging requires preparation of external equipment other than the cassette 3A at the time of radiation irradiation.
An example of such an external device is a grid rocking device that is provided on the radiation entrance surface of cassette 3A and is used to rock a grid when photographing.

Some of the external devices described above are configured to transmit an irradiation permission signal to the radiation control unit 11 after completion of preparation for imaging. For this reason, the radiation control unit 11 may be provided with a connection unit for inputting an irradiation permission signal from an external device, and configured to transmit an irradiation signal to the high voltage generating unit 12 only when both an irradiation instruction signal from the radiation control console 41 and an irradiation permission signal from the external device are turned ON.
In this way, the irradiation permission signal is not input to the radiation control unit 11 until the external device is ready to take an image, so that it is possible to prevent radiation from being irradiated before the external device is ready to take an image.

For example, if the external device is the grid rocking device described above, it can be configured so that after the grid rocking device starts rocking and reaches a designated rocking speed, an irradiation permission signal is input from the grid rocking device to the radiation control unit 11. In this way, the radiation control unit 11 outputs an irradiation signal only when it receives both an irradiation instruction signal from the irradiation instruction switch 5 based on the operation of the photographer and an irradiation permission signal from the external device, making it possible to prevent radiation from being irradiated before the external device is ready.

On the other hand, if it is not desired to use the irradiation permission signal from an external device in the radiation control unit 11, it is necessary to, for example, invalidate the irradiation permission signal or keep the irradiation permission signal always in an ON or OFF state.
For example, if the radiation control unit 11 is configured to be able to switch whether or not to use an irradiation permission signal from an external device to determine whether or not to output an irradiation signal, it can also be disabled by switching it so that it is not used in the determination.
On the other hand, if such switching is not possible and, for example, the irradiation permission signal is configured to be indicated by opening or closing two signal lines, the irradiation permission signal is always kept in the ON or OFF state by always keeping the two signal lines open or closed.

In addition, the radiation control unit 11 can be configured not to transmit an irradiation signal even if it detects that the irradiation instruction signal has been turned ON until a predetermined waiting time has elapsed since it detected that the irradiation preparation signal has been turned ON.
In this way, when the high voltage generating unit 12 or the radiation generating unit is configured to require a certain amount of time for preparation after detecting that the irradiation preparation signal has been turned ON, it is possible to prevent radiation from being emitted before irradiation preparation is complete.

The high voltage generating unit 12 is configured to be able to output an irradiation preparation output to the radiation generating unit 2 based on detection that an irradiation preparation signal from the radiation control unit 11 has been turned ON.
In addition, the high voltage generating unit 12 is configured to be able to apply, based on receiving an irradiation signal from the radiation control unit 11, a high voltage (corresponding to the input irradiation signal) required for the radiation generating unit 2 to generate radiation as an irradiation output to the radiation generating unit 2.
Note that FIG. 1 illustrates a configuration in which, when the high voltage generating unit 12 detects that the irradiation preparation signal from the radiation control unit 11 has been turned ON, the high voltage generating unit 12 outputs an irradiation preparation output to the radiation generating unit 2. However, the radiation control unit 11 can also be configured to directly output an irradiation preparation signal to the radiation generating unit 2, which then converts the signal into an irradiation preparation output in the radiation generating unit 2 to perform irradiation preparation.

The radiation generating unit 2 (radiation tube) includes, for example, an electron gun and an anode, and is configured to be capable of generating radiation (for example, X-rays) in response to the high voltage applied from the high voltage generating unit 12 .
Specifically, when a high voltage is applied, the electron gun irradiates an electron beam onto the anode, and the anode receives the electron beam to generate radiation.
In addition, since the part of the anode that receives the electron beam heats up and becomes hot when radiation is being generated, in order to irradiate radiation stably, it is necessary to constantly change the position on the anode where the electron beam is irradiated. Therefore, a rotating anode that irradiates the electron beam while rotating the anode may be used.
The above-mentioned irradiation preparation output from the high voltage generating unit 12 can be used, for example, as an instruction to start rotation of the rotating anode.

Cassette 3A contains a radiographic film or fluorescent screen, and when radiation that has passed through the subject enters it, it is possible to form a radiographic image of the subject.

The radiation control console 41 is configured to be able to set information about the subject and imaging conditions (tube voltage, tube current, irradiation time, etc.) to the radiation control unit 11 using an information signal connection.
In addition, the radiation control console 41 may be capable of communicating with a higher-level system 7 (such as a Radiology Information System (RIS), a Picture Archiving and Communication System (PACS), etc., see Figures 4 and 14) via an external communication network N, such as an in-hospital LAN.

The irradiation instruction switch 5 is used by the radiographer to instruct irradiation of radiation.
The irradiation instruction switch 5 in this embodiment is configured to be operable in two stages. Specifically, when the first stage is pressed, the irradiation preparation signal to be output to the radiation control console 41 is turned on, and when the second stage is pressed, the irradiation instruction signal to be output to the radiation control console 41 is turned on.
In addition, FIG. 1 illustrates a configuration in which the irradiation instruction switch 5 is connected to the radiation control console 41, and the irradiation preparation signal and irradiation instruction signal output by the irradiation instruction switch 5 are input to the radiation control unit 11 via the radiation control console 41. However, the irradiation instruction switch 5 may be connected to the radiation control unit 11, and the irradiation preparation signal and irradiation instruction signal may be input directly to the radiation control unit 11.

[motion]
Next, the operation of the conventional system 100A will be described.

(Irradiation preparation operation)
When the first step of the irradiation instruction switch 5 is pressed by the photographer, the irradiation instruction switch 5 turns on an irradiation preparation signal that is output to the radiation control unit 11 via the radiation control console 41 .
When the radiation control unit 11 detects that the irradiation preparation signal has been turned ON, it turns ON the irradiation preparation signal to be output to the high voltage generating unit 12 and makes the irradiation preparation signal available for output to an external device.
When the high voltage generating unit 12 detects that the irradiation preparation signal has been turned ON, it outputs an irradiation preparation output to the radiation generating unit 2 .

When the radiation generation unit 2 receives the irradiation preparation output, the radiation generation unit 2 starts preparation for generating radiation.
When the anode is a rotating anode, the preparation for generating radiation refers to, for example, an operation of rotating the rotating anode.

(Irradiation operation)
Subsequently, when the photographer presses the second stage of the irradiation instruction switch 5 , the irradiation instruction switch 5 turns on the irradiation instruction signal to be output to the radiation control unit 11 via the radiation control console 41 .
When the radiation control unit 11 detects that the irradiation instruction signal has been turned ON, it puts the irradiation instruction signal into a state in which it can be output to an external device, and transmits the irradiation signal to the high voltage generating unit 12 .
In addition, when the radiation control unit 11 is configured to determine whether or not radiation can be irradiated based on an irradiation permission signal from an external device, when the irradiation instruction signal from the irradiation instruction switch 5 or the radiation control console 41 is ON and an irradiation permission signal is received from an external device, the radiation control unit 11 will send an irradiation signal to the high voltage generating unit 12.

Upon receiving the irradiation signal, the high voltage generating unit 12 applies a high voltage required for the radiation generating unit 2 to irradiate radiation to the radiation generating unit 2 (performs irradiation output).
When a high voltage is applied from the high voltage generating unit 12 to the radiation generating unit 2, the radiation generating unit 2 generates radiation according to the applied voltage.
The generated radiation is irradiated onto the subject and the cassette 3A behind it with the irradiation direction, area, radiation quality, etc. adjusted by a controller such as a collimator (not shown). A part of the radiation passes through the subject and enters the cassette 3A.
When radiation enters cassette 3A, a radiation image is formed on a film or fluorescent screen stored therein.

Here, if the timing at which the above-mentioned irradiation preparation signal and the irradiation instruction signal are turned ON are close to each other, irradiation may occur, for example, before the rotation of the rotating anode of the radiation generating unit 2 reaches a sufficient speed, causing localized parts of the rotating anode to become excessively heated, damaging the rotating anode, or causing the amount of radiation irradiated to become unstable (for example, being insufficient or excessive compared to the irradiation intensity of the electron beam).
However, if the radiation control unit 11 is configured as described above so as not to transmit an irradiation signal even if it detects that the irradiation instruction signal has been turned ON until a predetermined waiting time has elapsed after detecting that the irradiation preparation signal has been turned ON, it is possible to prevent such problems from occurring.

In this way, in radiography using the conventional system 100A, only one radiographic image (still image) of the subject is captured based on one imaging operation.

First Embodiment
Next, a first embodiment of the present invention will be described with reference to Figures 2 to 11. Note that the same components as those in the above-mentioned Prior Art 1 are given the same reference numerals, and the description thereof will be omitted.

[System configuration]
First, a system configuration of a radiation imaging system according to this embodiment (hereinafter, referred to as a system 100) will be described.

As shown in FIG. 2, the system 100 according to this embodiment is obtained by replacing the cassette 3A of the conventional system 100A with a radiographic image capturing device (hereinafter, referred to as the capturing device 3) and further adding an capturing device control console 42 and an additional device 6.
In addition, there are cases where a plurality of generating devices are connected to the system 100, and in such cases, one of these generating devices is selected for use.
Similarly, there are cases where a plurality of image capture devices 3 are connected to the system 100, and in such cases, one of these will be selected for use.

An example of a system 100 in which such a plurality of generators and a plurality of imaging devices 3 are installed is shown in Fig. 27. In the example of the system 100 shown in Fig. 27, one each of a supine position imaging table 8A and an upright position imaging table 8B is installed in an imaging room (not shown), and a generator (A) and a generator (B) are installed mainly to correspond to the imaging of these tables.
The supine position radiography stand 8A is mainly provided with a radiography device (A), and the upright position radiography stand 8B is provided with a radiography device (B). The supine position radiography stand 8A and the upright position radiography stand 8B are each configured to accommodate the radiography device 3 in a changeable manner.
In addition to the above, an imaging device (C) is installed in the imaging room for taking partial images of, for example, hands, feet, etc., without using an imaging table. When using the imaging device (C), it may be placed on, for example, a supine imaging table 8A and imaging may be performed using the generator (A), or imaging may be performed by changing the irradiation direction of the radiation generating unit (B).
In addition, the console 4 and each of the multiple devices (the radiation control device 1, 1A and the additional devices 6, 6A) may be connected via a communication device 9 as shown in Figure 27, or may be connected via a communication network N.

With this configuration, for example, when capturing still images, and there are no particular restrictions on the capture size, it is possible to minimize the need to replace the imaging device 3 or move the radiation generating unit 2, and perform imaging efficiently.
However, for example, if the imageable size or image resolution of each imaging device 3 does not match the imaging technique to be performed, imaging will be performed by switching between the imaging devices (A), (B), and (C).

The imaging device 3 according to this embodiment includes an imaging control unit 31, a radiation detection unit 32, a scan drive unit 33, a readout unit 34, a storage unit 35, a communication unit 36, and the like, as shown in FIG. 3, in addition to a housing and a scintillator (not shown). Each of the units 31 to 36 is supplied with power from a battery 37.

The housing is provided with a power switch, a changeover switch, an indicator, a connector 36b of a communication unit 36 (described later), and the like, all of which are not shown.
When exposed to radiation, the scintillator emits electromagnetic waves with longer wavelengths than radiation such as visible light.

The imaging control unit 31 is composed of a computer with a central processing unit (CPU), read only memory (ROM), random access memory (RAM), input/output interface, etc. connected to a bus (not shown), a field programmable gate array (FPGA), etc. It may also be composed of a dedicated control circuit.

The radiation detection unit 32 is designed to generate electric charges by receiving radiation, and is composed of a substrate 32a, a plurality of scanning lines 32b, a plurality of signal lines 32c, a plurality of radiation detection elements 32d, a plurality of switching elements 32e, a plurality of bias lines 32f, a power supply circuit 32g, etc.
The substrate 32a is formed in a plate shape and is disposed so as to face the scintillator in parallel.
The multiple scanning lines 32b are provided to extend parallel to one another at predetermined intervals.
The signal lines 32c are arranged to extend parallel to one another at a predetermined interval, to extend perpendicular to the scanning lines 32b, and to be not electrically connected to the scanning lines.
That is, the plurality of scanning lines 32b and signal lines 32c are provided to form a lattice.

Each radiation detection element 32d generates an electrical signal (current, charge) corresponding to the dose of radiation irradiated to the radiation detection element (or the amount of electromagnetic wave light converted by the scintillator), and is composed of, for example, a photodiode or a phototransistor.
The radiation detection elements 32d are provided on the surface of the substrate 32a in a plurality of regions partitioned by the scanning lines 32b and the signal lines 32c. That is, the radiation detection elements 32d are arranged in a matrix. Therefore, each radiation detection element 32d faces a scintillator.
One terminal of each radiation detection element 32d is connected to a drain terminal of a switch element 32e, which is a switch element, and the other terminal is connected to a bias line.

Similar to the radiation detection elements 32d, the multiple switch elements 32e are provided in multiple regions defined by the multiple scanning lines 32b and the multiple signal lines 32c.
Each switch element 32e has a gate electrode connected to the adjacent scanning line 32b, a source electrode connected to the adjacent signal line 32c, and a drain electrode connected to one terminal of the radiation detection element 32d in the same region.

The multiple bias lines 32f are connected to the other terminals of each of the radiation detection elements 32d.
The power supply circuit 32g generates a reverse bias voltage and applies the reverse bias voltage to each radiation detection element via a bias line 32f.

The scan driver 33 includes a power supply circuit 33a, a gate driver 33b, and the like.
The power supply circuit 33a generates an on-voltage and an off-voltage, which are different from each other, and supplies them to the gate driver 33b.
The gate driver 33b switches the voltage applied to each scanning line 32b between an ON voltage and an OFF voltage.

The readout section 34 includes a plurality of readout circuits 34a, an analog multiplexer 34b, an A/D converter 34c, and the like.
The plurality of readout circuits 34a are connected to the signal lines 32c of the radiation detection unit 32, respectively, and are adapted to apply a reference voltage to each of the signal lines 32c.
Each read circuit 34a is composed of an integrating circuit 34d and a correlated double sampling circuit (hereinafter referred to as a CDS circuit) 34e.

The integration circuit 34d integrates the charge discharged to the signal line 32c, and outputs a voltage value according to the amount of integrated charge to the CDS circuit 34e.
The CDS circuit 34e samples and holds the output voltage of the integration circuit 34d before applying an on-voltage to the scanning line 32b to which the radiation detection element 32d from which the signal is to be read out is connected (while an off-voltage is being applied), applies an on-voltage to the corresponding scanning line 32b to read out the signal charge of the radiation detection element, and outputs the difference in the output voltage of the integration circuit 34d after applying an off-voltage to the corresponding scanning line 32b.

The analog multiplexer 34b outputs the plurality of differential signals output from the CDS circuit 34e one by one to the A/D converter 34c.
The A/D converter 34c sequentially converts the input image data of analog voltage values into image data of digital values.

The memory unit 35 is composed of SRAM (Static RAM), SDRAM (Synchronous DRAM), NAND type flash memory, HDD (Hard Disk Drive), etc.

The communication unit 36 includes an antenna 36a and a connector 36b for communicating with the outside.
The communication unit 36 can select whether to perform wireless communication or wired communication based on a control signal from the outside. That is, when wireless communication is selected, wireless communication is performed using the antenna 36a, and when wired communication is selected, information can be transmitted and received using a wired LAN or the like. When synchronization is to be performed using wired communication, synchronization can be performed using a protocol such as NTP (Network Time Protocol) or a method defined in the international standard IEEE 1588.

When the imaging device 3 configured in this way is turned on, it takes one of the following states: "initialization state,""storagestate," and "reading and transfer state." The timing for switching states will be described later.
The "initialized state" is a state in which an on voltage is applied to each switch element 32e and the charge generated by the radiation detection element 32d is not accumulated in each pixel (the charge is discharged to the signal line 32c).
The "accumulation state" is a state in which an off voltage is applied to each switch element 32e, and charges generated by the radiation detection elements 32d can be accumulated in the pixels (charges are not released to the signal lines 32c).
The “read/transfer state” is a state in which an on voltage is applied to each switch element 32e and the readout unit 34 is driven to read out image data based on the incoming charges and transmit it to another device.
Depending on the configuration of the element and device, the accumulated charge may be cleared by reading, so "reading" and "initialization" may not be distinguished as separate operations, and may be performed simultaneously as the same operation.

Note that, here, an example will be described of a so-called indirect type in which the radiated radiation is converted into electromagnetic waves of another wavelength, such as visible light, to obtain an electrical signal; however, the present invention may also be applied to a so-called direct type imaging device in which radiation is directly converted into an electrical signal by a detection element.
Further, other configurations of the imaging device 3 are not necessarily limited to those illustrated in FIG. 3 as long as they are capable of generating image data of a radiation image.

As shown in FIG. 2, the imaging apparatus control console 42 is configured to transmit and receive information signals to and from the radiation control console 41 and to set information about the subject, imaging conditions, and the like, in the imaging apparatus 3 .
It should be noted that the radiation control console 41 sets the radiation control unit 11, and the imaging device control console 42 sets the imaging device 3. However, since these both perform settings related to the same imaging, in the following explanation, they may be collectively referred to as the console 4 in a broad sense.
The console 4 and the additional device 6 constitute a radiation generation control system according to the present invention.

In addition, Figure 2 illustrates a configuration in which when shooting conditions, etc. are set on the shooting device control console 42, the settings are set in the radiation control unit 11 via the radiation control console 41 (by the radiation control console 41 and the shooting device control console 42 sending and receiving information signals), but it is also possible to configure the radiation control unit 11 to be set directly from the shooting device control console 42.
It is also possible to configure the imaging device 3 so that the settings are made from the radiation control console 41 .
In addition, while FIG. 2 illustrates an example of a configuration in which the console 4 is connected to the imaging device 3 via an additional device 6, the console 4 can be directly connected to the imaging device 3, or can be connected to the imaging device 3 via a communication network N, for example, as shown in FIG. 2.

Furthermore, the console 4 is capable of setting the operation of the additional device 6 .
Specifically, it is possible to set in the additional device 6 the number of times (maximum number of shots) that the additional device 6 will output an irradiation permission signal (the third signal in the present invention) or the output time for which the irradiation permission signal will be repeatedly output.

The console 4 may be provided with a display unit 43, and the number of outputs or the output time set in the additional device 6 may be displayed on the display unit 43.
Furthermore, the console 4 may be configured to display on the display unit 43 that irradiation is possible when an imaging start signal (a second signal in the present invention, described in detail later) input to the additional device 6 is turned ON.
Furthermore, the console 4 may be configured to display on the display unit 43 a message indicating that radiation is being irradiated while the additional device 6 is outputting an irradiation permission signal.

The additional device 6 is a radiation generation control device in the present invention, and is configured with an additional control unit 61 having a first acquisition unit 62, a second acquisition unit 63, a first connection unit 64, and a second connection unit 65.

The additional control unit 61 can be configured to comprehensively control the operation of each unit of the additional device 6 using a CPU, RAM, etc.
In this case, various processing programs stored in a storage unit (not shown) are read out and loaded into the RAM, and various processes are executed in accordance with the processing programs.

The first acquisition unit 62 serves as a contact point (e.g., a connector) with the radiation control unit 11, and in this embodiment, acquires the irradiation preparation signal output by the irradiation instruction switch 5 via the radiation control unit 11 (generator).

The second acquisition unit 63 serves as a contact point (e.g., a connector) with the radiation control unit 11, and in this embodiment, acquires the irradiation instruction signal output by the irradiation instruction switch 5 via the radiation control unit 11 (generator).
As described above, the irradiation instruction signal corresponds to the first signal in the present invention, and therefore the second acquisition unit 63 forms the acquisition unit in the present invention.

The first connection portion 64 serves as a contact point (for example, a connector) with the imaging device 3, and is capable of inputting an irradiation start signal.
In addition, the irradiation start signal is a signal that turns ON when the photographing device 3 is in a state where photographing is possible, and turns OFF when photographing is not possible, so it is a signal that indicates the driving state of the photographing device 3 in the present invention.

In this embodiment, the second connection part 65 is a connector, and it is possible to connect to the radiation control unit 11 (generator) by inserting the other end of a cable whose one end is connected to the radiation control unit 11 (generator).
Then, it is possible to output an irradiation permission signal to the radiation control unit 11 .

Note that Figure 2 illustrates a configuration in which the first acquisition unit 62, the second acquisition unit 63, the first connection unit 64, and the second connection unit 65 directly transmit and receive information and signals to and from other devices (the first and second acquisition units 63 and the second connection unit 65 are the radiation control device 1, and the first connection unit 64 is the imaging device 3), but at least one of the first acquisition unit 62, the second acquisition unit 63, the first connection unit 64, and the second connection unit 65 may be connectable to other devices via a relay unit (not shown) that is capable of relaying signals.
In addition, although FIG. 2 illustrates an example in which the first acquisition portion 62, the second acquisition portion 63, the first connection portion 64, and the second connection portion 65 are provided separately, at least two of the first acquisition portion 62, the second acquisition portion 63, the first connection portion 64, and the second connection portion 65 may be integrally configured (each of the portions 62 to 65 may be used for multiple purposes).

The additional control unit 61 of the additional device 6 configured in this manner is capable of repeatedly outputting a pulsed irradiation permission signal instructing irradiation of radiation from the second connection unit 65 to the radiation control unit 11 at a predetermined period based on the irradiation instruction signal acquired from the radiation control unit 11 via the second acquisition unit 63 and the irradiation start signal input from the imaging device 3 via the first connection unit 64.
In addition, the additional control unit 61 may be configured not to output an irradiation permission signal even if it detects that the shooting start signal has been turned ON until a predetermined waiting time has elapsed since it detected that the irradiation start signal has been turned ON.

In addition, the additional control unit 61 is configured to output a timing signal (fourth signal in the present invention) indicating the timing of capturing a radiographic image from the first connection unit 64 to the imaging device 3 based on the timing of outputting the irradiation permission signal.
The imaging timing is, for example, the timing for starting the accumulation of charges for a radiation image. That is, the imaging device 3 according to this embodiment starts accumulating charges in accordance with a timing signal, and the timing means of the imaging device 3 sequentially finishes the accumulation, reads out the charges of each pixel, converts the charges of each pixel into an image, and stores and transfers the image.
By controlling in this manner, the additional control unit 61 can control both the timing of radiation irradiation based on the irradiation permission signal and the accumulation timing of charge accumulation during radiation irradiation based on the timing signal. As a result, charge due to radiation irradiation can be reliably accumulated, and an image due to radiation irradiation can be reliably acquired.

In addition, when the start of the charge accumulation operation is set to the above-mentioned shooting timing in this manner, the imaging device 3 may wait in a state in which it is possible to transition to the accumulation timing corresponding to the shooting operation by irradiating radiation, and start the accumulation operation in accordance with the timing signal.
By controlling in this manner, the additional control unit 61 can reliably obtain images by irradiating radiation in the same manner as in the above case.

Furthermore, the image capturing timing triggered by the input of this timing signal can be the timing to start any of the various operations that the image capturing device 3 repeatedly performs, other than the charge accumulation operation.
For example, in the case where it is necessary to reset the charge accumulated in each pixel before the accumulation operation, the timing to start the resetting may be set as the shooting timing.
In this case, the image capturing device 3 may be configured to sequentially transition to a storage operation after the reset is completed.
By using this type of control, it is possible to reset and release dark charge, which is a noise component that accumulates over time in each pixel before the accumulation of charge due to radiation exposure, and then enter into the accumulation operation of charge accumulation due to radiation exposure, making it possible to obtain an image with less noise.

Alternatively, the timing at which the accumulation operation ends may be set as the imaging timing, or the timing at which the readout of the accumulated electric charges starts in response to a timing signal may be set as the imaging timing.
By controlling in this manner, the additional control unit 61 can control both the timing of radiation irradiation based on the irradiation permission signal, and the timing of ending the accumulation of charge due to radiation irradiation based on the timing signal, and the timing of reading out the charge accumulated by radiation irradiation. As a result, the charge due to radiation irradiation can be reliably accumulated, and further, an image due to radiation irradiation can be reliably acquired.

The timing signals may be used not to start but to end each operation. For example, a storage operation may be started in synchronization with the timing signal changing from OFF to ON, and the storage operation may be ended in synchronization with the timing signal changing from ON to OFF.
By controlling in this manner, the additional control unit 61 can reliably obtain images by irradiating radiation in the same manner as in each of the above cases.

In this embodiment, the timing signal is repeatedly outputted at the same cycle as the irradiation permission signal.
In this embodiment, the additional control unit 61 repeatedly outputs the irradiation permission signal until a predetermined number of outputs is reached, or until a predetermined output time has elapsed since the first output.

The timing signal may be output with a predetermined delay or advance from the output of the irradiation permission signal.
Furthermore, since the additional control unit 61 repeatedly transmits a timing signal and an irradiation permission signal at a predetermined cycle, it can be configured to have a timer means for controlling the timing.
The additional control unit 61 may be configured to have a counting means for counting the number of outputs in order to repeatedly output the timing signal or the irradiation permission signal until a predetermined number of outputs are reached, or may be configured to have a timer means for repeatedly outputting the timing signal or the irradiation permission signal until a predetermined output time has elapsed since the first output.

Also, the timing signal may be output from a stage before the second stage of the irradiation instruction switch 5 is pressed (the irradiation instruction signal is acquired).
Specifically, the signal can be configured to be output, for example, between acquiring a sequence start signal (the fifth signal in the present invention) (detecting that it has turned ON) and acquiring an irradiation instruction signal, or between acquiring an irradiation preparation signal (the sixth signal in the present invention) (detecting that it has turned ON) and acquiring an irradiation instruction signal.

[motion]
Next, a description will be given of the operation of the system 100. Figures 4 to 6 are ladder charts showing the operation of the system 100 according to this embodiment, Figure 7 is a table showing the correspondence between the generator and image capture device 3 connectable to the system 100 and the frame rates compatible with them, Figures 8 to 10 are examples of the display screen of the display unit 43 of the console 4, and Figure 11 is a timing chart showing the operation of the system 100.

(A: When installing equipment, when starting up the equipment, when changing connected equipment, and when periodically checking connected equipment)
First, as shown in FIG. 4, the console 4, particularly the imaging device control console 42, checks the imaging devices 3 and additional devices 6 connected to the imaging environment controlled by the console 4 when installing equipment, starting up the imaging system, changing connected devices, and during other periodic connected device checks (step S1), and displays the equipment configuration and connection configuration on the display unit 43 of the console 4 (step S2).
The imaging devices 3 and additional devices 6 connected to the imaging environment controlled by the console 4 can be confirmed, for example, by the console 4 requesting the imaging devices 3 and additional devices 6 for their connection status and IDs, and the imaging devices 3 and additional devices 6 returning their connection status and IDs.
As the ID, for example, an ID unique to each device, such as a MAC address set uniquely to the device, a BSSID set uniquely to the device, or a serial number set uniquely to the device, can be used, or an ID set later, such as a set IP address or a set ESSID, can be used.

(B: Preparation for shooting)
Thereafter, when the console 4 receives an imaging order from a higher-level system 7 such as a RIS or HIS (step S3), the console 4 displays the received imaging order on the screen of the console 4 (step S4).
At this time, the operator may be notified by using light or sound that a new imaging order has been received.
The photographer performs operations such as changing the photographing order from the displayed photographing order, and selects the next photographing order (step S5).

Meanwhile, in the system 100 according to the present embodiment, unlike a fluoroscopic device in which the combination of a radiation generating means and a radiographic image capturing means is fixed, imaging can be performed even if the combination of the generating means and the capturing device 3 is changed. Therefore, it is possible to perform imaging by selecting an imaging device suitable for an imaging order or imaging technique from among a plurality of cassette-type imaging devices 3 with different sizes and performance.
In this case, as shown in FIG. 7, for example, from among a plurality of imaging devices 3 that can be connected to the console 4 and used for imaging, an imaging device 3 (e.g., imaging device (A) or (C)) suitable for the current imaging is selected and imaging is performed.
Although not shown in the figure, in the case of a system 100 in which multiple generators are connected to one console 4, the generator to be used for shooting (e.g., generator (A) or (B)) is selected and shooting is performed.

The additional control unit 61 of the additional device 6 or the console 4 according to this embodiment is capable of acquiring the irradiation frame rate or the imaging frame rate when selecting at least one of the generating device and the imaging device 3 .
The illumination frame rate and imaging frame rate to be acquired may be input (selected) by the photographer into the console 4 , or may be received from the generating device or imaging device 3 .
Furthermore, when receiving from the generating device or the imaging device 3, one frame rate selected by each device may be received, or all of the multiple frame rates supported by each device may be received.
The additional control unit 61 or the console 4 having such functions constitutes the first and second acquisition means in the present invention.

In order for photography to be performed without any problems, it is necessary to satisfy all of the following conditions (1) to (3). Therefore, the additional control unit 61 or the console 4 judges whether or not all of these conditions are satisfied.
(1) The acquired irradiation frame rate is a value corresponding to the generator. (2) The acquired photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
Here, the “irradiation frame rate” refers to the number of times the radiation generator generates radiation per unit time, and corresponds to the transmission period of the irradiation permission signal by the additional control unit 61 .
On the other hand, the “imaging frame rate” refers to the number of times that the imaging device 3 generates a radiographic image per unit time, and corresponds to the transmission period of the timing signal by the additional control unit 61 .
When at least one of the irradiation frame rate and the imaging frame rate is multiple, there will be multiple combinations of the irradiation frame rate and the imaging frame rate, and therefore multiple determinations may be made accordingly.
Further, although N is an integer of 1 or more here, it is preferable to set N to an integer of 2 or more when, for example, imaging is performed by thinning out the radiation irradiation at a predetermined interval.
By executing this process, the additional control unit 61 or the console 4 serves as the determining means in the present invention.

In addition, when there are multiple shooting frame rates received from the shooting device 3 and/or multiple illumination frame rates received from the generating device, there can be multiple combinations of shooting frame rates and illumination frame rates, so it is possible to determine in advance whether or not each of them satisfies all of the above-mentioned discrimination conditions.
Furthermore, if the generating device, the photographing device 3, and the console 4 are configured to allow only the selection of irradiation frame rates and photographing frame rates that are compatible with the generating device and the photographing device, the determination of whether or not the above discrimination conditions (1) and (2) are met can be omitted.

As a result of checking whether or not all of the above discrimination conditions are satisfied, if any one of the above discrimination conditions is not satisfied, it is advisable to take at least one of the following measures (4) to (6).
(4) Selection of the imaging device 3 to be used, the generating device to be used, the imaging frame rate of the imaging device 3, and the radiation emission rate of the generating device that do not satisfy the above relationship is not permitted, and input values are not accepted (not set).
(5) Setting candidates that do not satisfy the above relationship are grayed out (a display is provided to notify the user of the determination result) or the like, so that they are removed from the selection list and cannot be selected.
(6) Even if a selection can be made, the user is not allowed to proceed to the next sequence, or to take a picture.
When taking the above-mentioned measures, the camera may be notified of the error and warned that the above-mentioned relationship is not satisfied. The warning may be given by voice or by displaying the result of the determination using the display unit 43.

In other words, the additional control unit 61 or the console 4 has a function as a notification means in the present invention that notifies the photographer of the discrimination result in a manner that can be identified by the photographer, or a function as an output means in the present invention that outputs the discrimination result.
Furthermore, when all of the above determination conditions (1) to (3) are satisfied, the additional control unit 61 or the console 4 permits the generator to irradiate radiation. In other words, the additional control unit 61 or the console 4 serves as the irradiation permission means of the present invention.
In this way, it is possible to reliably prevent photography from being performed in a state where a selection has been made that does not satisfy the above relationship.

Here, the operation for setting the irradiation frame rate and the photographing frame rate will be explained using as an example the case of a photographing room having other combinations of photographing devices (A) and (C) and a combination of generating devices (A) and (B) as shown in Figure 7.
First, assume that the photographer selects the generator (A) as the generator to be used (displays the generator (A) in the display field 43a for the selected generator) as shown in Fig. 8. The irradiation frame rates (at which irradiation is possible) corresponding to the generator (A) are, for example, three types of 15, 10, and 5 frames/s (Hz).
Note that Figure 8 illustrates an example in which generating device (A) is selected and only information about generating device (A) is displayed in display field 43a, but it is also possible to configure display field 43a so that information about a plurality of generating devices can be displayed in the form of options, and the information about the selected generating device (A) can be displayed in a different manner from the information about the other generating devices.

Next, the imaging device 3 to be used is selected. In this case, imaging device (A) and imaging device (C) are selectable because their corresponding imaging frame rates include values that are N times (N is an integer equal to or greater than 1) the irradiation frame rates (15, 10, 5) that can be handled by the previously selected generating device (A).
Therefore, when the photographing device (A) is selected (the corresponding icon 43b is displayed in a solid line), due to the combination with the irradiation frame rate corresponding to the generating device (A), the selectable photographing frame rate is 15 Hz (three times the irradiation frame rate of 5 Hz).
Among these selectable shooting frame rates, it is possible to select a shooting frame rate with a relatively large (fast) value as the basic shooting frame rate.
In a procedure in which imaging is performed by changing the irradiation frame rate, if the imaging frame rate is changed in accordance with the change in the irradiation frame rate, complicated and time-consuming work such as restarting the imaging device (A) due to a change in the settings of the imaging device (A) will be required. However, by fixing the imaging frame rate of the imaging device (A) to the basic imaging frame rate, it is possible to eliminate such switching time.
In this way, when 15 Hz is selected as the basic shooting frame rate, the irradiation frame rate can be selected from 15 Hz or 5 Hz, which is 1/N (where N is an integer greater than or equal to 1) of the basic shooting frame rate, among the irradiation frame rates that the generating device (A) can support.
In this case, when an attempt is made to select 10 Hz as the irradiation frame rate, the selection may be disabled. In this case, for example, as shown in Fig. 9, a display indicating that the selection is disabled (a display notifying the result of the determination: for example, the character "not allowed" 43c) may be displayed near the displayed irradiation frame rate.

On the other hand, as another example, as shown in FIG. 10, when the imaging device (C) is selected (the corresponding icon 43d is displayed in a solid line), it becomes possible to select 10 Hz as the basic imaging frame rate due to the corresponding frame rate of the generating device.
The irradiation frame rate can be selected from 10 Hz and 5 Hz.
In addition, it is desirable to set the irradiation frame rate to a value required according to the imaging technique. For example, in order to image the dynamics of slow changes such as breathing, it is desirable to set the irradiation frame rate to at least 2 Hz.
For this reason, the additional control unit 61 or the console 4 can be configured to permit the generator to irradiate radiation when the set irradiation frame rate is 2 Hz or higher.
Alternatively, the minimum required frame rate can be stored for each area to be imaged and each procedure, and the generator can be configured to permit radiation irradiation if the irradiation frame rate set according to the selected area to be imaged and each procedure is equal to or higher than the minimum required frame rate.

Moreover, a configuration may be adopted in which an imaging apparatus 3 recommended in accordance with the imaging technique of the photographer is automatically selected from among a plurality of imaging apparatuses 3 connected.
Also, if there is no particular change, the image capturing device 3 used in the previous image capturing may be continuously selected.

When the imaging device 3 to be used is selected, as shown in FIG. 4, the console 4 sends connection requests to the imaging device 3 and the additional device 6 (step S6).
When the image capturing device 3 and the additional device 6 receive the connection request, they each connect to the console 4 (step S7).
As shown in FIG. 4, the connection request may be sent from the console 4 to the additional device 6, and further from the additional device 6 to the image capturing device 3.
The photographing device 3 and the console 4 can be connected via a communication network N or directly, as shown in FIG. 2. However, if the console 4 and the photographing device 3 are directly connected, there is a possibility that the photographing device 3 will be connected to a photographing device 3 that is not connected to an additional device 6, and it may not be possible to establish a connection configuration in which the additional device 6 and the photographing device 3 are linked together.
However, by connecting the imaging device 3 and the console 4 via the additional device 6 in this manner, it is possible to reliably connect to the imaging device 3 connected to the additional device 6 .

Alternatively, although not shown in the figure, a connection request may be sent from the console 4 to each imaging device 3 , and then each imaging device 3 may send a connection request to the additional device 6 .
Since the settings of the imaging device 3 to be used for imaging are performed on the console 4, this configuration allows the imaging device 3 to be reliably selected and connected to the additional device 6, making it possible to establish a linked state between the additional device 6 and the imaging device 3 to be used without selecting the wrong imaging device 3.
Furthermore, with this configuration, it becomes possible to select and connect a photographing device 3 from all available photographing devices 3, not just from the photographing devices 3 connected to the additional device 6 as described above.
In addition, the photographing device 3 may be configured to automatically transition its state from the aforementioned low power consumption mode in which photographing is prepared or photographing is possible to a mode with higher power consumption than the low power consumption mode when a connection is started.

Next, when the photographer sets the photographing conditions and the like on the console 4 and instructs the console 4 to start photographing, the console 4 turns on a sequence start signal that instructs the photographing device 3 and the additional device 6 to start a photographing sequence. Then, the sequence start signal is transmitted to the photographing device 3 and the additional device 6 (step S8). The sequence start signal can be transmitted, for example, by using an information signal transmitted and received between the console 4 and the additional device 6, or an information signal transmitted and received between the additional device 6 and the photographing device 3.
When the photographing device 3 and the additional device 6 detect that the sequence start signal has been turned ON, they start preparation for photographing.

Here, if the additional device 6 is configured to transmit a timing signal before the irradiation instruction switch 5 is pressed, after the additional device 6 detects that the sequence start signal has been turned ON, it may turn ON a read instruction signal (see Figure 18) and control the timing signal to be repeatedly transmitted to the photographing device 3 at a predetermined interval (step S9).
The photographing device 3 repeats the read operation every time it receives this timing signal, which increases the temperature of the circuits in the photographing device 3. In other words, the repeated read operations performed by the photographing device 3 at this stage serve to warm up the photographing device 3.
In addition, in the initial stage in which the image capture device 3 repeats the readout operation, the image capture device 3 notifies the console 4 that the warm-up has started (step S10).

Incidentally, the image capturing device 3 needs to be subjected to a read operation (reset operation) to remove the accumulated electric charge immediately before image capturing.
On the other hand, the imaging device 3 consumes power when performing a readout operation, which increases the temperature of the imaging device 3. This temperature increase also changes the sensitivity of the imaging device 3, particularly of the light receiving section, and also changes the image density output in response to the amount of incident radiation. If a single still image is captured, this change in image due to the temperature increase is not a problem, but when dynamic imaging (repeated capture of still images) is performed as in the system 100 according to this embodiment, the change in image due to the temperature increase during imaging becomes a problem.
However, as described above, if the warm-up is performed, the change in image density caused by such a rise in temperature can be reduced.

Furthermore, the photographing device 3 may obtain a correction image at some timing while step S9 is being repeated a number of times.
For example, if the photographing device 3 is configured to warm up (perform a read operation before pressing the irradiation instruction switch 5), the image read during the latter half of this warm-up may be transmitted to the console 4 as a correction image (step S11).
The multiple pixels in the imaging device 3 each have different characteristics, and even when not irradiated with radiation, the charge level corresponding to the brightness of the image differs for each pixel. Therefore, an image read out in the latter half of the warm-up is acquired as a correction image, and for example, by subtracting each signal value of the correction image from each signal value of a later acquired imaging image, it is possible to obtain an imaging image in which the variation between pixels has been removed.
Although the correction image is used here by simply subtracting it from the captured image, it is also possible to remove noise components using various calculations.

In addition, during a read operation (reset operation) for removing the charge accumulated immediately before the shooting other than obtaining the correction image, at least one of the following steps may be performed as operations similar to those performed during normal shooting: imaging the removed charge, storing the imaged image data in a memory unit within the shooting device 3, and transferring the imaged data or the image data stored in the memory unit within the shooting device 3 to the console 4.
Performing the above steps in the same way as for normal photography will result in conditions closer to actual photography, so by doing so, there will be less difference when photography is performed in subsequent steps, and it will be possible to minimize the effects of the temperature rise, for example.
On the other hand, if the above steps are performed in the same way as for normal imaging, there are problems such as increased power consumption, unnecessary images not exposed to radiation being stored in the memory of the imaging device 3, reducing the capacity of the memory available for use during imaging, and unnecessary images not exposed to radiation being sent to the console, occupying part of the communication capacity, and being stored in the memory of the console, reducing the capacity of the memory available for use during imaging. In order to avoid these problems, it is also possible to omit some of the above steps.

The imaging device 3 can be configured to complete warm-up when a preset number of readouts or a readout operation period has elapsed as warm-up. For example, in step S25 (see FIG. 5) in which an irradiation start signal is turned ON, which will be described later, the irradiation start signal is not turned ON until the preset number of readouts or the readout operation period has elapsed, so that imaging by irradiation with radiation is not started until warm-up is completed.

Thereafter, the imaging device 3 notifies the console 4 that the imaging preparation is complete (step S12).
At this time, the display unit 43 of the console 4 may display "photography possible" (step S13).

(C: Confirmation of photo)
The additional device 6 continues to repeatedly transmit the timing signal to the photographing device 3, and the photographing device 3 repeats its read operation every time it receives this timing signal.
When the radiographer finishes positioning the subject and presses the first step of the irradiation instruction switch 5 (step S14), the irradiation instruction switch 5 turns on an irradiation preparation signal to be output to the radiation control unit 11 via the console 4 (step S15).
When the radiation control unit 11 of the generating device detects that the irradiation preparation signal has been turned ON, it turns ON the irradiation preparation signal to be output to the high voltage generating unit 12 and the additional device 6 (step S16). As a result, the first acquisition unit 62 of the additional device 6 acquires the irradiation preparation signal (output before the irradiation instruction signal and after the sequence start signal is turned ON).
In this manner, the radiation generating device including the radiation control unit 11 starts preparation for radiation irradiation in response to the irradiation preparation signal.

When the additional control unit 61 of the additional device 6 detects that the irradiation preparation signal from the radiation control unit 11 has been turned ON, it transmits an imaging preparation signal to the console 4 (step S17).
At this time, the additional control unit 61 or the console 4 may check again the following determination conditions (1) to (3).
(1) The set irradiation frame rate is a value corresponding to the generator. (2) The set photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
If the above relationship is not satisfied, the console 4 may prohibit progression to the following sequence or may not issue permission to shoot.
Furthermore, when taking the above measures, the photographer may be notified of an error, and the photographer may be warned that the above relationship is not satisfied.

When the console 4 receives the imaging preparation signal, it starts imaging preparation. The imaging preparation in the console 4 is, for example, an operation of confirming that the settings of the imaging device control console 42 constituting the console 4 and the settings of the radiation control console 41 that controls the irradiation of radiation are the same, and confirming that imaging conditions and the like designated for the imaging device 3 are set.
When the console 4 completes the preparation for imaging, it turns on the imaging preparation completion signal to be output to the additional device 6 (step S18).
At this time, the display unit 43 of the console 4 may display "shooting" (step S19).

In addition, when the preparation for imaging is completed, the input of imaging condition changes and the like to the console 4 may be locked so that no changes can be made.
In the case of still image shooting, since shooting is completed in a short time, there is little risk of changing the shooting conditions during shooting, and there is little need for such a configuration. However, in the case of dynamic image shooting, since the shooting period is long, there is a higher risk that the photographer or a third party other than the photographer will intentionally or unintentionally operate the console screen to change the shooting conditions, etc.
Therefore, by locking inputs such as changes to the imaging conditions to the console 4 from this stage until the end of the sequence from step S45 onwards, which will be described later, it is possible to reliably prevent such changes to the imaging conditions.

Although Figure 4 shows an example of a case where a shooting preparation signal is output from the additional device 6 to the console 4, there is also the case where the shooting preparation signal is output to the shooting device 3 instead of the console 4, the shooting device 3 is caused to prepare for shooting, and when the shooting preparation of the shooting device 3 is completed, a shooting preparation completion signal is output from the shooting device 3 to the additional device 6.
In addition, a shooting preparation signal may be output to both the console 4 and the imaging device 3, causing each to prepare for shooting, and when both preparations for shooting are complete, a shooting completion signal may be sent from the console 4 and the imaging device 3 to the additional device 6, and when the additional device 6 receives both shooting completion signals, it may be determined that overall preparation for shooting is complete.

Also, although not shown in the figure, if the radiation control unit 11 of the generating device has a connection unit for inputting an imaging preparation completion signal that can be input to indicate that imaging preparation of an external device is complete, the additional device 6 may be configured to output the imaging preparation completion signal to the radiation control unit 11.
The radiation control unit 11 detects that the imaging preparation completion signal from the additional device 6 has turned ON, thereby making it possible to detect that the imaging device 3 is in a state where imaging is possible. Here, the radiation control device 1 controls radiation irradiation after detecting that the imaging preparation completion signal has turned ON, thereby making it possible to reliably eliminate the risk that the imaging device 3 will irradiate radiation in a state where imaging is not possible, resulting in unnecessary exposure of the subject to radiation.

(D: Shooting execution)
Next, when the photographer presses the second stage of the irradiation instruction switch 5 (step S20), the irradiation instruction switch 5 turns on an irradiation instruction signal to be transmitted to the radiation control unit 11 via the console 4 (step S21).
At this time, the additional device 6 continues to repeatedly transmit a timing signal to the photographing device 3, and the photographing device 3 repeats the read operation every time it receives this timing signal.
Even if an irradiation instruction signal is input from the irradiation instruction switch 5, the radiation control unit 11 of the generating device does not transmit an irradiation signal to the high voltage generating unit 12 because the irradiation permission signal from the additional device 6 is OFF at this point.

On the other hand, the radiation control unit 11 turns on the irradiation instruction signal to be transmitted to the additional control unit 61 (step S22).
When the additional device 6 receives the irradiation instruction signal, it turns on an imaging start signal which is output to the imaging device 3 and the console 4 and notifies whether or not the start of imaging is permitted (steps S23 and S24).
At this time, the additional control unit 61 or the console 4 may check again the following determination conditions (1) to (3).
(1) The set irradiation frame rate is a value corresponding to the generator. (2) The set photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
If the above relationship is not satisfied, the console 4 may prohibit progression to the following sequence or may not issue permission to shoot.
Furthermore, when taking the above measures, the photographer may be notified of an error, and the photographer may be warned that the above relationship is not satisfied.

When the imaging device 3 detects that the imaging start signal has been turned ON, it uses the completion of its own readout operation at that time as a trigger to turn ON the irradiation start signal to be output to the additional device 6, for example as shown in FIG. 5 (step S25). This is because the readout operation of the imaging device 3 is performed by sequentially reading out the charges accumulated in the two-dimensionally arranged pixels to obtain an image of the entire light receiving surface. If the irradiation start signal is turned ON during the readout and radiation is irradiated, a difference will occur in the signal values between pixels for which reading has been completed and pixels for which reading has not been completed, resulting in a significant degradation of image quality.

In contrast, in this embodiment, as described below, radiation irradiation and image readout by the imaging device 3 are performed based on an irradiation permission signal and a timing signal from the additional device 6, so radiation irradiation during a readout operation does not occur in normal routines. For this reason, the irradiation start signal may be configured to be turned ON without considering the readout timing of the imaging device 3 described above.

The imaging device 3 continues to read out images even after the irradiation start signal is turned ON. The images read out after the irradiation start signal is turned ON are stored as captured images in the memory of the imaging device 3 or transferred to the console 4.

When the additional device 6 detects that the irradiation start signal from the imaging device 3 has been turned ON, it detects that the imaging device 3 is in an imaging-enabled state, and repeatedly transmits an irradiation permission signal to the radiation control unit 11 (step S26).
When the irradiation frame rate: shooting frame rate is set to 1:N, the additional control unit 61 outputs a shooting permission signal once every N times it outputs a timing signal (Figure 5 shows the case where N = 2).

The radiation control unit 11 of the generating device repeatedly transmits the irradiation signal to the high voltage generating unit 12 every time it receives the irradiation permission signal, since both the imaging instruction signal and the irradiation permission signal are received.
The high voltage generating unit 12 repeatedly generates a high voltage necessary for irradiating radiation every time it receives an irradiation signal, and repeatedly outputs the high voltage to the radiation generating unit 2 as an irradiation output.
The radiation generating unit 2 repeatedly irradiates the imaging device 3 with radiation every time the irradiation output is input (step S27).
The irradiated radiation passes through a subject (not shown) disposed between the imaging device 3 and the radiation generating unit 2 , and enters the imaging device 3 .

Meanwhile, the imaging device 3 accumulates electric charges in an amount corresponding to the intensity of the incident radiation each time it receives a timing signal (step S28), and reads out the electric charges as a captured image (step S29).
The imaging device 3 continues to repeat accumulation and readout, and every N times accumulation and readout are repeated, radiation is irradiated from the generator once to generate an exposure image.
The imaging device 3 transfers the read-out radiation image to the console 4 (step S30).
In addition, if the captured images are configured to be transferred to the console 4, and the transfer to the console 4 cannot be completed in time due to the amount of data or the communication environment, some of the multiple captured images, or part of a single captured image, may be stored in the photographing device 3, and the remainder may be transferred to the console 4.

Here, a further explanation will be given of an example of the operation of the image capturing device 3. Here, a case where accumulation of charges starts in accordance with the above-mentioned timing signal will be explained.
<Reset operation/corrected image acquisition operation>
In the reset operation performed before imaging, the imaging device 3 repeats the above-mentioned operation in the absence of radiation irradiation from the radiation generating device, and discharges charges (dark charges or dark currents) accumulated in each pixel that are not based on radiation irradiation, thereby resetting the charges accumulated in each pixel that are not based on radiation irradiation and that become noise components in an image due to charges based on radiation irradiation. Note that, during this reset operation, the above-mentioned readout unit 34 may be controlled not to convert the charges that have flowed in into image data. (Operation before t1)

In addition, in the correction image acquisition operation performed before or after shooting, the imaging device 3 repeats the above-mentioned operation in the absence of radiation irradiation from the radiation generating device, and releases the charges (dark charges or dark currents) accumulated in each pixel that are not based on radiation irradiation, thereby resetting the charges accumulated in each pixel that are not based on radiation irradiation and become noise components in the image due to charges based on radiation irradiation. In addition, during this correction image acquisition operation, the charges that flow in at the readout unit 34 are converted into image data and stored, making it possible to store the amount of noise components in the absence of radiation irradiation, and the noise components can be removed by subtracting them from the image data in the radiation irradiation state. Note that this correction image acquisition operation may be performed as part of the reset operation described above. (Operation before t1)

<Reset operation/Completion operation of corrected image acquisition operation>
When the irradiation instruction signal is turned ON in step S21 following the reset operation or the correction image acquisition operation, the photography start signal input to the photographing device 3 is turned ON (step S23). Then, the photographing device 3 stops the reset operation or the correction image acquisition operation described above.
On the other hand, even if the shooting start signal is ON, if the correction image acquisition operation has not completed acquiring the specified number of correction images, the correction image acquisition operation is not stopped, but is continued until the specified number of correction images are acquired, and then the correction image acquisition operation is stopped.
When the reset operation or the correction image acquisition operation is stopped, the photographing device 3 stops the reset operation or the correction image acquisition operation, and notifies the user that it is in a photographing possible state by turning on the irradiation start signal in step S25 (t1).

<Operation>
When the imaging device 3 receives a timing signal from the additional control unit 61, it applies an off voltage to each scanning line 32b, thereby transitioning to a state in which the charge generated by the radiation detection element 32d can be accumulated in the pixel, as shown in Figure 11 (t2, t6, t10, ...).
The additional control unit 61 outputs an irradiation permission signal at a timing linked to the timing at which the timing signal was transmitted. The radiation generation device irradiates the imaging device 3 with radiation in response to the irradiation permission signal (step S27; t3, t7, t11, ...).
When the irradiation frame rate is 1/N of the imaging frame rate (FIG. 11 shows the case where N=2), the additional control unit 61 outputs an irradiation permission signal once every N times that it outputs the timing signal. As a result, in response to the timing signal and the irradiation permission signal, the radiation generating device irradiates radiation once every N times that the imaging device 3 repeats storage and readout (step S27; t3, t11, ...). At that time, radiation is not irradiated at other times (t7, ...).
The photographing device 3 continues the mode of accumulating electric charges for a predetermined period of time using its own timer (t2 to t4, t6 to t8, t10 to t12, . . . ).

When the imaging device 3 receives radiation while in the charge accumulation mode, it generates charges in the radiation detection elements 32d of the radiation detection section 32 and accumulates the charges in each pixel (step S28).
After that, the image capturing device 3 performs a readout operation in which the charge accumulated in each pixel is discharged to the signal line 32c by applying an on-voltage to each switch element 32e after the predetermined time has elapsed using its own timer. In the readout operation, the image capturing device 3 reads out image data based on the charge that has flowed in at the readout section 34 and converts the image data into image data. In addition, at least a part of the converted image data is transferred to the console 4 (steps S29, S30; t4-t5, t8-t9, t12-t13, ...).

<Another embodiment of the operation control method>
In the above explanation, an example was shown in which the imaging device transitions to a state in which charge can be accumulated in a pixel in response to a timing signal from the additional control unit 61, but it is also possible to control the imaging device to perform other operations in response to this timing signal.
For example, in another control method, after the imaging device 3 completes the read operation (t4 to 5, t8 to t9, t12 to t13, ...) in which the charge accumulated in each pixel is released to the signal line 32c, the imaging device 3 may be controlled to transition to a state in which charge can be accumulated in the pixel (t6 to t8, t10 to t12, ...) without waiting for a timing signal from the additional control unit 61.
Thereafter, the additional control unit 61 controls the radiation generating device to output a timing signal at a timing linked to the timing of transmission of an irradiation permission signal for controlling irradiation of radiation.
In response to the received timing signal, the image capturing device 3 transitions to a readout operation in which the charge accumulated in each pixel is discharged to the signal line 32c (t4, t8, t12, ...).
By repeating such operational control, it is possible to perform imaging while synchronizing the radiation irradiation timing by the radiation generating device with the image generation timing by the imaging device.

(E: End of filming)
The additional device 6 counts the number of times that the irradiation permission signal has been transmitted from the point in time when irradiation of radiation has started, and judges each time whether or not the number of images to be captured has reached a preset maximum number. If it is judged that the counted number of times that the irradiation permission signal has been transmitted (the number of images captured) has reached the maximum number of images to be captured, the additional device 6 turns off the imaging start signal (step S31) as shown in Fig. 6, and stops outputting either or both of the timing signal and the irradiation permission signal.

Here, the additional device 6 may be controlled to perform the following operation at least once after the final output of the irradiation permission signal: the imaging device 3 accumulates an amount of charge according to the intensity of the incident radiation (step S28) and reads it out as a captured image (step S29). This ensures that the image finally irradiated with radiation can be read out and used as a captured image, and it is possible to reliably prevent the subject from being unnecessarily exposed to radiation.
Furthermore, the additional device 6 may be configured to control the imaging device 3 to accumulate electric charges (step S28) after outputting the final irradiation permission signal, read out the accumulated electric charges as a captured image (step S29), and then further accumulate electric charges and read out the accumulated electric charges as a captured image. Since these captured images are images captured without irradiation with radiation, these images can be used for correcting the captured images when radiation is irradiated, in the same manner as the above-mentioned correction images.

In other words, as a correction image, an image captured before imaging using radiation as described above may be used as the correction image, or an image captured after imaging using radiation as described above may be used as the correction image.
Alternatively, correction images taken before and after radiography may be used. In this case, by using the correction images before and after radiography, a correction image may be generated by predicting changes in the correction image during radiography. These can be generated, for example, by averaging the correction images taken before and after radiography, or by linearly or curve-interpolating the changes.
In the case of still image shooting, the time required for shooting is short, so there is little change in the correction image before and after shooting, but in the case of dynamic shooting, the time required for shooting is much longer than for still images. Therefore, by using the correction images before and after shooting as described above, it is possible to perform correction that takes into account the fluctuations during shooting.

Furthermore, the number of shots may be counted based on the number of times the timing signal is output after the start of shooting, rather than counting the number of times the irradiation permission signal is transmitted as described above.
Furthermore, the number of shots may be counted based on the time that has elapsed since the start of shooting, instead of counting the number of times that the irradiation permission signal has been transmitted as described above.

When the imaging device 3 detects that the imaging start signal has been turned OFF, and further when imaging after the aforementioned radiation exposure and imaging for obtaining correction images are completed, it turns OFF the read instruction signal (see FIG. 18) and transfers the remaining images (untransferred captured images) left in the memory of the imaging device 3 to the console 4 (step S32). Then, when the transfer of the remaining images is completed, it sends a remaining image transfer completion signal to the console 4 (step S33).

On the other hand, when the console 4 detects that the image capture start signal has been turned off, it starts the task of checking the transferred captured image.
Furthermore, when the console 4 receives the remaining image transfer completion signal, it transmits an image deletion signal to the photographing device 3 to instruct the image deletion (step S34).
The image deletion signal may be controlled so as to be transmitted after the confirmation of the captured images is completed and it is confirmed that there are no problems with all the transferred images.
At this time, "imaging completed" may be displayed on the display unit 43 of the console 4 (step S35).
When the photographing device 3 receives the image deletion signal, it deletes the photographed image stored in the memory (step S36), thereby making it possible to secure free memory space for the next photographing.

When the photographer confirms that shooting has ended (for example, by visually confirming the “Shooting Ended” display on the console 4), he or she releases the second stage of the irradiation instruction switch 5 (step S37). The irradiation instruction switch 5 then turns the irradiation instruction signal OFF (step S38), and the radiation control unit 11 also turns the irradiation instruction signal OFF (step S39).
Thereafter, when the photographer releases the first step of the irradiation instruction switch 5 (step S40), the irradiation instruction switch 5 turns the irradiation preparation signal OFF (step S41), and further the radiation control unit 11 also turns the irradiation preparation signal OFF (step S42).
When the additional device 6 detects that the irradiation preparation signal has been turned OFF, it notifies the console 4 of this fact.
When the console 4 receives the notification from the additional device 6, it turns off the imaging preparation completion signal and transitions the sequence state to an irradiation preparation state.

When the additional device 6 detects that the irradiation instruction signal and the irradiation preparation signal have been turned off, it transmits an imaging end signal indicating that imaging has ended to the imaging device 3 and the console 4 (steps S43, S44).
When the photographing device 3 receives the photographing end signal, it transmits a standby signal to the console 4 (step S45).
When the console 4 receives the standby signal, it monitors for a predetermined period of time whether or not re-shooting or other shooting is performed, and if the predetermined period of time has passed without re-shooting or other shooting, it turns off the sequence start signal and transitions the sequence state to a standby state in which it waits for a shooting instruction.
Thus, a series of photographing operations is completed.
The system 100 according to this embodiment operates as described above, thereby performing dynamic photography in which a plurality of still images are repeatedly captured in a short period of time.

[Select image after shooting]
Then, on the console 4, from the multiple frames that make up the obtained dynamic image, which include exposure images taken at the time when radiation was irradiated every N frames (with N-1 unexposed images generated without being irradiated between the exposure images), only the exposure images are extracted and used as a new dynamic image, making it possible to obtain a dynamic image with 1/N of the radiation exposure amount.
The extraction of the exposure image may be performed based on the set irradiation frame rate, the shooting frame rate, and the frame number assigned to the dynamic image, or may be performed by determining the pixel value of a specified pixel in each frame.
Through such operations, the console 4 functions as a selection means and a dynamic image generating means in the present invention.
Furthermore, when extracting an exposed image, an image correction process for the exposed image may be performed, if necessary, using an unexposed image generated at a timing other than that for generating the exposed image.

[Modification 1]
In the above example, an example has been described in which all captured images are sent from the imaging device 3 to the console 4, and the console 4 extracts necessary images (exposed images) and generates dynamic images, but it is also possible to configure the imaging device 3 to select exposed images or unexposed images generated at other times and send them to the console 4 instead of sending all captured images to the console 4. Also, the imaging device 3 may perform image correction processing on the exposed images as necessary.

[Modification 2: Counting the number of shots taken by the photographing device 3]
In the above embodiment, an example has been shown in which the additional device 6 counts the number of times that it transmits an irradiation permission signal, and when the counted number of times that the irradiation permission signal is output reaches the maximum number of images to be captured, it is determined that the maximum number of images to be captured has been reached. However, the device may be configured to count the number of times that the imaging device 3 receives a timing signal after transmitting an irradiation start signal, or the number of times that the imaging device 3 is read out after receiving a timing signal, or the number of times that the imaging device 3 is read out and images are stored or transferred to the console 4, and to determine whether or not the number of times the number of times the number of images to be captured has reached a preset maximum number of images to be captured.

[Modification 3: Permission to photograph depending on the state of the photographing device]
In addition, when the imaging device 3, the console 4, and the additional device 6 are connected, or when imaging starts, the remaining power amount and remaining memory amount of the imaging device 3 may be referenced to determine whether the specified dynamic imaging can be completed.
Also, depending on the result of the determination, if shooting is possible, a display indicating that shooting is possible may be provided.
Also, depending on the result of the determination, if photography is not possible, a message to that effect may be displayed.

[Modification 4: Operation of the radiation control unit during dynamic imaging]
In the above embodiment, the radiation control unit 11 receives an irradiation instruction signal from the irradiation instruction switch 5 and also repeatedly receives an irradiation permission signal from the additional control unit 61 .
This irradiation permission signal is transmitted to the radiation control unit 11 as a pulse signal corresponding to the irradiation of radiation for capturing, for example, each frame of a dynamic image. Then, the radiation control unit 11 transmits an irradiation signal to the high voltage generating unit 12 in a one-to-one correspondence with each of the irradiation permission signals that are repeatedly received, and irradiates radiation.
Furthermore, when capturing one still image, it is sufficient for the radiation control unit 11 to transmit an irradiation permission signal once in response to receiving an irradiation instruction signal once.

Therefore, in order to capture a still image, an irradiation permission signal is received multiple times in response to a single irradiation instruction signal, and in order to prevent radiation from being erroneously irradiated multiple times, the radiation control unit 11 can be configured to transmit an irradiation signal only once in response to the input of the first irradiation permission signal, even if an irradiation permission signal is received multiple times in response to a single irradiation instruction signal.

On the other hand, if the radiation control unit 11 is configured to send an irradiation signal only once in response to one irradiation permission signal as described above, it will not be possible to perform dynamic imaging by repeatedly irradiating radiation multiple times in response to one irradiation instruction signal, as in the system 100 of this embodiment.
Therefore, the radiation control unit 11 may be configured to transmit an irradiation signal to the high voltage generating unit 12 multiple times when the radiation control unit 11 receives an irradiation permission signal multiple times during a single irradiation instruction signal input period, which is the period during which the photographer presses the irradiation instruction switch 5.
In this manner, dynamic imaging can be performed by repeating radiation irradiation a number of times in response to a single irradiation instruction signal.

In addition, the above-mentioned (1) control mode in which an irradiation signal is transmitted only once in response to one irradiation permission signal, and (2) a control mode in which, when an irradiation permission signal is input multiple times during an irradiation instruction signal input period, an irradiation signal is transmitted multiple times to the high voltage generating unit 12 in response to the input of the irradiation permission signal, may be switched depending on the type of shooting (still image shooting or dynamic shooting).
The control mode of the radiation control unit 11 according to the type of imaging can be switched by the console 4, and may be configured to be changed based on the reception of a signal indicating the type of imaging from the console 4.
With this configuration, it is possible to reliably prevent the risk of the subject being unnecessarily exposed to radiation due to mistaken irradiation of radiation multiple times when capturing a still image.

[Modification 5: Timing restriction of radiation control unit during dynamic imaging]
For example, if electrical noise is mixed into the irradiation permission signal transmitted from the additional control unit 61 to the radiation control unit 11, causing the radiation control unit 11 to receive a signal similar to the irradiation permission signal at an unintended timing, the high voltage generating unit 12 may experience a situation similar to that in which the high voltage generating unit 12 repeatedly receives the irradiation permission signal at such short intervals that it is unable to generate the high voltage required for radiation irradiation. In such a case, if the radiation control unit 11 forcibly transmits an irradiation signal to the high voltage generating unit 12, an excessive current may flow through the high voltage generating unit 12, causing the high voltage generating unit 12 to break down.

Therefore, in the above embodiment, it is also possible to configure the radiation control unit 11 so that, when the irradiation permission signal is repeatedly received from the additional control unit 61 while the irradiation instruction signal input from the irradiation instruction switch 5 is ON, the length of the reception interval between two successive irradiation permission signals is compared with a preset minimum reception interval, and if it is determined that the reception interval is shorter than the minimum reception interval, it will not transmit the irradiation signal to the high voltage generating unit 12.
In this way, it is possible to prevent an excessive current from flowing through the high voltage generating unit 12, which would cause the high voltage generating unit 12 to break down.

[effect]
As described above, in the system 100 according to this embodiment, the radiation control device 1 can output an irradiation signal multiple times in response to acquisition of a single irradiation instruction signal (ON detection) by connecting the additional control unit 61 to the radiation control device 1 in the conventional system 100A shown in Fig. 1, which can only irradiate radiation once in response to a single radiation irradiation instruction signal. In other words, the generator can repeatedly generate radiation at a predetermined cycle. This makes it possible to perform imaging using the imaging device 3, in which frames are repeatedly generated at a predetermined cycle based on the received radiation, i.e., dynamic imaging.
1 is widely used as a system capable of capturing simple still images, and therefore medical institutions using the conventional system 100A can easily modify the conventional system 100A including the existing generator into one capable of capturing dynamic images by simply adding the imaging device 3 and the additional device 6, without having to update the expensive generator.

In addition, the system 100 according to this embodiment is configured to notify the photographer of the result of determining whether the imaging frame rate acquired by the additional control unit 61 or the console 4 is N times the acquired irradiation frame rate (where N is an integer equal to or greater than 1) in a manner that is recognizable to the photographer. This reliably prevents the risk of imaging being started with a frame rate that is not compatible with at least one of the imaging device 3 and the generator when imaging is performed in which the generator irradiates radiation the same number of times or less than the predetermined number of times while the imaging device 3 repeats charge accumulation and readout a predetermined number of times.

<Prior Art 2>
Next, a description will be given of Prior Art 2, which is the basis of a system 200 (described in detail later) according to a second embodiment of the present invention, with reference to Fig. 12. Note that the same components as those in Prior Art 1 above are given the same reference numerals, and the description thereof will be omitted.

[System configuration]
First, a schematic configuration of a radiation imaging system according to Prior Art 2 (hereinafter, referred to as a conventional system 200A) will be described. Fig. 12 is a block diagram showing a schematic configuration of the conventional system 200A.

In the conventional system 200A, as shown in FIG. 12, for example, the configuration of a radiation control unit 11A included in a radiation control device 1A is different from that of the conventional system 100A.
Specifically, the radiation control unit 11 of the conventional system 100A was configured to be able to output an irradiation preparation signal or an irradiation instruction signal from the radiation control console 41 to an external device based on detecting that the signal has been turned ON, but the radiation control unit 11A of the conventional system 200A does not have such a configuration.
Furthermore, the radiation control unit 11 of the conventional system 100A was configured to be capable of receiving an irradiation permission signal from an external device, but the radiation control unit 11A of the conventional system 200A does not have such a configuration.

[motion]
Next, the operation of the conventional system 200A will be described.

(Irradiation preparation operation)
When the first step of the irradiation instruction switch 5 is pressed by the photographer, the irradiation instruction switch 5 turns on an irradiation preparation signal that is output to the radiation controller 11 A via the radiation control console 41 .
When the radiation control unit 11A detects that the irradiation preparation signal has been turned ON, it turns ON the irradiation preparation signal to be output to the high voltage generating unit 12 .
Although FIG. 12 does not show the output of an irradiation preparation signal from the radiation control unit 11A to an external device, if the radiation control unit 11A operates in cooperation with an external device, the irradiation preparation signal may be output to the external device.
When the high voltage generating unit 12 detects that the irradiation preparation signal has been turned ON, it outputs an irradiation preparation output to the radiation generating unit 2 .

When the radiation generation unit 2 receives the irradiation preparation output, the radiation generation unit 2 starts preparation for generating radiation.
When the anode is a rotating anode, for example, an operation such as rotating the rotating anode is performed.

(Irradiation operation)
Subsequently, when the photographer presses the second stage of the irradiation instruction switch 5, the irradiation instruction switch 5 turns on the irradiation instruction signal to be output to the radiation controller 11A via the radiation control console 41.
Although FIG. 12 does not show the output of an irradiation instruction signal from the radiation control unit 11A to an external device, when operating in cooperation with an external device, an irradiation instruction signal may be output to the external device.

In the conventional technique 2, since it is not configured to receive an irradiation permission signal from an external device, the control of transmitting an irradiation signal when both an irradiation instruction signal and an irradiation permission signal are received is not performed. Therefore, the radiation control unit 11A transmits an irradiation signal to the high voltage generation unit 12 only by detecting that the irradiation instruction signal has been turned ON.
Upon receiving the irradiation signal, the high voltage generating unit 12 applies a high voltage required for radiation irradiation in the radiation generating unit 2 to the radiation generating unit 2 as an irradiation output.
When a high voltage is applied from the high voltage generating unit 12 to the radiation generating unit 2, the radiation generating unit 2 generates radiation according to the applied voltage.
The generated radiation is irradiated onto the subject and the cassette 3A behind it with the irradiation direction, area, radiation quality, etc. adjusted by a controller such as a collimator (not shown). A part of the radiation passes through the subject and enters the cassette 3A.
When radiation enters cassette 3A, a radiation image is formed on a film or fluorescent screen stored therein.

Here, in order to prevent irradiation from occurring before the rotation of the rotating anode reaches a sufficient speed, similar to the above-mentioned conventional technique 1, the radiation control unit 11A may be configured not to transmit an irradiation signal even if it detects that the irradiation instruction signal has been turned ON, until a predetermined waiting time has elapsed since it detected that the irradiation preparation signal has been turned ON, as described above.

In this way, in radiography using the conventional system 200A, just like when the above-mentioned conventional system 100A is used, only one radiographic image (still image) of the subject is captured based on one imaging operation.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Figures 13 to 16. Note that the same reference numerals are used to designate the same components as those in the first embodiment, and the description thereof will be omitted. In addition, the various modified patterns given in the first embodiment can also be applied to this embodiment.

[Premise, Background, Issues]
Among radiation imaging systems, there are those as shown in the above-mentioned prior art 1 in which the radiation control unit 11 has an input unit for an external irradiation permission signal and transmits an irradiation signal in response to an irradiation instruction from the photographer and irradiation permission from the outside. On the other hand, there are also radiation control units 11A as shown in the above-mentioned prior art 2 in which the radiation control unit 11A only has an input unit for an irradiation instruction signal from the outside and captures a still image.
The radiation imaging system according to this embodiment (hereinafter, referred to as the system 200) is capable of performing continuous imaging by adding an additional device 6A to the radiation control unit 11A.

[System configuration]
First, a description will be given of the system configuration of the system 200. Fig. 13 is a block diagram showing a schematic configuration of the system 200 according to the second embodiment.

As shown in FIG. 13, for example, a system 200 according to the present invention is configured by replacing the cassette 3A of the conventional system 200A shown in FIG. 12 with an imaging device 3, and further including an imaging device control console 42 similar to that of the first embodiment, and an additional device 6A.
In addition, like the system 100 of the first embodiment, the system 200 may be connected to a plurality of generators as shown in FIG. 27, and in such a case, one of these generators will be selected for use.
Similarly, there are cases where a plurality of image capture devices 3 are connected to the system 200, and in such cases, one of these will be selected for use.

The additional device 6A includes an additional control unit 61A and an interface unit (hereinafter, I/F unit 67).
Although FIG. 13 shows an example of the additional device 6A in which the additional control unit 61A and the I/F unit 67 are separate, these may be integrated into one unit.

The additional control unit 61A has a third connection unit 66 in addition to a first acquisition unit 62, a second acquisition unit 63, a first connection unit 64, and a second connection unit 65 similar to those in the first embodiment.
The I/F unit 67 also includes a first AND circuit 67a and a second AND circuit 67b.
The first acquisition unit 62 is connected to one input terminal of a first AND circuit 67a, and the third connection unit 66 is connected to the other input terminal of the first AND circuit 67a.
The second acquisition unit 63 is connected to one input terminal of a second AND circuit 67a, and the second connection unit 65 is connected to the other input terminal of a second AND circuit 67b.

In addition, in the system 100 according to the first embodiment, the irradiation instruction switch 5 is connected to the console 4, and the irradiation instruction switch 5 outputs an irradiation preparation signal and an irradiation instruction signal to the additional device 6 via the radiation control device 1, whereas in the system 200 according to the present embodiment, the irradiation instruction switch 5 capable of outputting an irradiation preparation signal and an irradiation instruction signal is directly connected to the additional device 6A.
The additional device 6A is capable of inputting an irradiation preparation signal and an irradiation instruction signal from the irradiation instruction switch 5 to the additional control unit 61A and one of the input units of the first and second AND circuits 67a and 67b of the I/F unit 67. That is, the first acquisition unit 62 can directly acquire the irradiation preparation signal and the second acquisition unit 63 can directly acquire the irradiation instruction signal from the irradiation instruction switch 5.
In addition, the board or device on which the irradiation instruction switch 5 is provided may be connected to the I/F unit 67, and the first and second acquisition units 62, 63 may be configured to acquire the irradiation preparation signal and the irradiation instruction signal output by the irradiation instruction switch 5 via the board or device.

In addition, in this embodiment, the third connection unit 66 outputs an imaging preparation completion signal, and the second connection unit 65 outputs an irradiation permission signal to the first and second AND circuits 67 a and 67 b, respectively. When an AND condition is satisfied in the first and second AND circuits 67 a and 67 b with the irradiation preparation signal and the irradiation instruction signal from the irradiation instruction switch 5, the irradiation preparation signal and the irradiation instruction signal can be output to the radiation control unit 11 via the radiation control console 41.
That is, the second connection unit 65 according to the present embodiment can be connected to the generator via the I/F unit 67. Therefore, the I/F unit 67 and the radiation control console 41 according to the present embodiment form a relay unit in the present invention.

In FIG. 13, the I/F unit 67 branches the irradiation preparation signal from the irradiation instruction switch 5 to be input to the additional control unit 61A and the first AND circuit 67a, and when the AND condition is satisfied with the imaging preparation completion signal from the additional control unit 61A, the I/F unit 67 outputs the irradiation preparation signal. However, the irradiation preparation signal does not have to be configured in this way, and may be directly output from the irradiation instruction switch 5 to the radiation control console 41 or the radiation control unit 11A.

In addition, although Figure 13 illustrates a configuration in which the third connection unit 66 directly transmits and receives information and signals to and from the imaging device 3, the third connection unit 66 may also be capable of connecting to other devices via a relay unit (not shown) that can relay signals.
In addition, although Figure 13 illustrates an example in which the first acquisition portion 62, the second acquisition portion 63, the first connection portion 64, and the second connection portion 65 are provided separately, at least two of the first acquisition portion 62, the second acquisition portion 63, the first connection portion 64, the second connection portion 65, and the third connection portion 66 may be integrally configured (each portion 62 to 66 may be used for multiple purposes).
Further, although not shown in the drawings, the irradiation preparation signal and the irradiation instruction signal outputted from the additional device 6A may be directly inputted to the radiation control unit 11A without going through the radiation control console 41.

The additional control unit 61A may execute a program different from that of the additional control unit 61 according to the first embodiment, and may have a structure similar to that of the additional control unit 61 according to the first embodiment. (Although not shown in FIG. 2, the additional control unit 61 according to the first embodiment also includes a third connection unit 66, but since the program does not include a command to use this, it is possible to use the same one as the additional control unit 61.) Alternatively, the additional control unit 61A may be separate from the additional control unit 61 and limited to the necessary functions.
When the additional control unit 61A detects that the irradiation preparation signal from the irradiation instruction switch 5 has been turned ON, it turns ON the shooting preparation signal to be output to at least one of the shooting device 3 and the console 4.
In addition, when the additional control unit 61A detects that a shooting preparation completion signal from at least one of the console 4 and the shooting device 3 is ON, it turns ON the shooting preparation completion signal to be output to the other input section of the first AND circuit 67a of the I/F unit 67.

In addition, when the additional control unit 61A detects that the irradiation instruction signal from the irradiation instruction switch 5 has been turned ON, it turns ON the shooting start signal to be output to at least one of the shooting device 3 and the console 4.
In addition, when the additional control unit 61A detects that an irradiation start signal from at least one of the console 4 and the imaging device 3 has been turned ON, it outputs an irradiation permission signal (e.g., a pulse-shaped signal) similar to that in the first embodiment to the other input unit of the second AND circuit 67b of the I/F unit 67 repeatedly at a predetermined period.
The additional control unit 61A is also configured to repeatedly output a timing signal (for example, a pulse signal) similar to that in the first embodiment to the photographing device 3 at a predetermined cycle.
In this way, in order to control the transmission timing of the irradiation permission signal and the timing signal, the additional control unit 61A can be configured to have a clock means similar to that of the first embodiment.

[motion]
Next, a description will be given of the operation of the above-mentioned system 200. Figures 14 to 16 are ladder charts showing the operation of the system 200 according to this embodiment.

A: Operations (steps S1, S2) when installing the equipment, starting up the device, changing the connected equipment, and periodically checking the connected equipment, and B: operations (steps S3 to S13) when preparing for shooting are the same as those in the first embodiment, as shown in FIG. 9.
That is, in the system 200 according to the present embodiment, like the system 100 according to the first embodiment, imaging can be performed even if the combination of the generator and the imaging device 3 is changed. Therefore, it is possible to select an imaging device suitable for an imaging order or imaging technique from among a plurality of cassette-type imaging devices 3 having different sizes and performances, and perform imaging.
In this case, as shown in FIG. 7, for example, from among a plurality of imaging devices 3 that can be connected to the console 4 and used for imaging, an imaging device 3 suitable for the current imaging is selected and imaging is performed.
Although not shown, in the case of the system 100 in which a plurality of generators are connected to one console 4, the generator to be used for imaging is selected and imaging is performed.

The additional control unit 61A of the additional device 6A or the console 4 according to this embodiment is capable of acquiring the irradiation frame rate or the imaging frame rate when selecting at least one of the generating device and the imaging device 3.
The additional control unit 61A or the console 4 is also capable of acquiring the shooting frame rate.
The illumination frame rate and imaging frame rate to be acquired may be input (selected) by the photographer into the console 4 , or may be received from the generating device or imaging device 3 .
Furthermore, when receiving from the generating device or the imaging device 3, one frame rate selected by each device may be received, or all of the multiple frame rates supported by each device may be received.
The additional control unit 61A or the console 4 having such functions constitutes the first and second acquisition means of the present invention.

In order for photography to be performed without any problems, it is necessary to satisfy all of the following conditions (1) to (3). Therefore, the additional control unit 61A or the console 4 judges whether or not all of these conditions are satisfied.
(1) The acquired irradiation frame rate is a value corresponding to the generator. (2) The acquired photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
Here, the “irradiation frame rate” refers to the number of times the radiation generator generates radiation per unit time, and corresponds to the transmission period of the irradiation permission signal by the additional control unit 61 .
On the other hand, the "imaging frame rate" refers to the number of times that the imaging device 3 generates a radiographic image per unit time, and corresponds to the transmission period of the timing signal by the additional control unit 61A.
When at least one of the irradiation frame rate and the imaging frame rate is multiple, there are multiple combinations of the irradiation frame rate and the imaging frame rate, and therefore multiple determinations may be made accordingly.
Further, although N is an integer of 1 or more here, it is preferable to set N to an integer of 2 or more when, for example, imaging is performed by thinning out the radiation irradiation at a predetermined interval.
By executing this process, the additional control unit 61A or the console 4 serves as the determining means in the present invention.

In addition, when there are multiple shooting frame rates received from the shooting device 3 and/or multiple illumination frame rates received from the generating device, there can be multiple combinations of shooting frame rates and illumination frame rates, so it is possible to determine in advance whether or not each of them satisfies all of the above-mentioned discrimination conditions.
Furthermore, if the generator, the imaging device 3, and the console 4 are configured to allow only the selection of irradiation frame rates and imaging frame rates that are compatible with the generator and the imaging device, it is possible to omit the determination of whether or not the above determination conditions (1) and (2) are met.

As a result of checking whether or not all of the above discrimination conditions are satisfied, if any one of the above discrimination conditions is not satisfied, it is advisable to take at least one of the following measures (4) to (6).
(4) Selection of the imaging device 3 to be used, the generating device to be used, the imaging frame rate of the imaging device 3, and the radiation emission rate of the generating device that do not satisfy the above relationship is not permitted, and input values are not accepted (not set).
(5) Setting candidates that do not satisfy the above relationship are grayed out (a display is provided to notify the user of the determination result) or the like, so that they are removed from the selection list and cannot be selected.
(6) Even if a selection can be made, the user is not allowed to proceed to the next sequence, or to take a picture.
When taking the above-mentioned measures, the camera may be configured to notify the photographer of an error and warn the photographer that the above-mentioned relationship is not satisfied. In this embodiment, the warning may be given by voice or by displaying the result of the determination using the display unit 43.

[C: Shooting confirmation (preparation for irradiation)]
The additional device 6A continues to repeatedly transmit the timing signal to the photographing device 3, and the photographing device 3 repeats its read operation every time it receives this timing signal.
When the radiographer finishes positioning the subject and presses the first step of the irradiation instruction switch 5 (step S14), the irradiation instruction switch 5 turns on the irradiation preparation signal to be output to the additional device 6A (step S15A).

The irradiation preparation signal is input to the additional control unit 61A and one of the input sections of the first AND circuit 67a of the I/F unit 67.
At this time, the other input section of the first AND circuit 67a is connected to the additional control section 61A. Therefore, even if the irradiation preparation signal input from the irradiation instruction switch 5 to one input section of the first AND circuit 67a is ON, if the imaging preparation completion signal input to the other input section is not ON, the irradiation preparation signal output from the first AND circuit 67a to the radiation control console 41 remains OFF.

When the additional control unit 61A detects that the irradiation preparation signal from the irradiation instruction switch 5 has been turned ON, it transmits an imaging preparation signal instructing preparation for imaging to at least one of the console 4 and the imaging device 3 (step S17).
At this time, the additional control unit 61A or the console 4 may check again the following determination conditions (1) to (3).
(1) The set irradiation frame rate is a value corresponding to the generator. (2) The set photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
If the above relationship is not satisfied, the console 4 may prohibit progression to the following sequence or may not issue permission to shoot.
Furthermore, when taking the above measures, the photographer may be notified of an error, and a warning may be given to the photographer that the above relationship is not satisfied.

When at least one of the console 4 and the imaging device 3 receives the imaging preparation signal, it prepares for imaging, and when the imaging preparation is complete, it turns on the imaging preparation completion signal that it outputs to the additional device 6A (step S18).

[Control of external device preparation for shooting]
Also, although not shown in the figure, if at least one of the console 4 and the photographing device 3 has a connection section for inputting a photographing preparation completion signal indicating whether or not preparation for photographing is complete from an external device, at least one of the console 4 and the photographing device 3 may be configured to turn on the photographing preparation completion signal when it detects that the photographing preparation completion signal from the external device has been turned on.
Alternatively, although not shown, the additional device 6A or the additional control unit 61A may be provided with a connection unit that outputs a shooting preparation signal to an external device, or a connection unit that can input a shooting preparation completion signal from an external device.
This makes it possible for the additional device 6A or the additional control unit 61A to instruct the external device to prepare for shooting, or to detect that the external device has completed preparation for shooting, and to output a shooting preparation completion signal to the I/F unit in response to the external device having completed preparation for shooting.

By detecting that the imaging preparation completion signal has been turned ON, the additional device 6A is able to know that at least one of the console 4 and the imaging device 3, or an external device, is in a state in which imaging is possible, and by controlling radiation irradiation to be performed after the imaging preparation completion signal has been turned ON, it is possible to reliably eliminate the risk of radiation being irradiated in a state in which imaging is not possible by at least one of the console 4 and the imaging device 3, or an external device, resulting in unnecessary exposure of the subject.

When at least one of the console 4 and the imaging device 3 detects that the imaging preparation signal has been turned ON, or when it enters the imaging preparation operation, or when it has completed the imaging preparation operation, it turns ON a signal indicating whether or not the imaging preparation signal has been received, a signal indicating whether or not the imaging preparation operation has been entered, or an imaging preparation completion signal indicating whether or not the imaging preparation operation has been completed, which is to be transmitted to the additional device 6A (step S18).

When the additional device 6A detects that the image capture preparation completion signal has been turned ON, it turns ON the image capture preparation completion signal to be output to the other input section of the first AND circuit 67a of the I/F section 67.
At this time, the irradiation preparation signal from the irradiation instruction switch 5 and the shooting preparation completion signal from the additional control unit 61A, which are input to the first AND circuit 67a of the I/F unit 67, are both turned ON, so the first AND circuit 67a turns ON the irradiation preparation signal to be output to the radiation control console 41.

When the radiation control console 41 detects that the irradiation preparation signal has been turned ON, it turns ON the irradiation preparation signal to be output to the radiation control unit 11A (generator). That is, the additional device 6A turns ON the irradiation preparation signal to be transmitted to the generator via the radiation control console 41 (step S18A).
When the generation device (radiation control unit 11A, high voltage generation unit 12, radiation generation unit 2) detects that the irradiation preparation signal has been turned ON, it performs preparation for radiation irradiation in the same manner as in the first embodiment.

Note that, here, a case has been described in which the additional device 6A confirms that the imaging preparation of the imaging device 3 or the console 4 has been completed (receives an imaging preparation completion signal) and then transmits an irradiation preparation signal to the radiation control unit 11A. However, a configuration may also be used in which the additional device 6A transmits an irradiation preparation signal to the imaging device 3 or the console 4 and at the same time to the radiation control unit 11A, without confirming that the imaging preparation of the imaging device 3 or the console 4 has been completed.
In this case, the first AND circuit 67a of the I/F unit 67 is not necessary, and the irradiation preparation signal received from the irradiation instruction switch 5 may be distributed to the console 4, the imaging device 3, the radiation control console 41, or the radiation control unit 11A, respectively.

[D: Shooting execution]
Next, when the photographer presses the second stage of the irradiation instruction switch 5 (step S20), the irradiation instruction switch 5 turns on the irradiation instruction signal to be output to the additional device 6A (step S21A).
At this time, the additional device 6A continues to repeatedly transmit a timing signal to the photographing device 3, and the photographing device 3 repeats the read operation every time it receives this timing signal.

The irradiation instruction signal is input to the additional control unit 61A and one of the input sections of the second AND circuit 67b of the I/F unit 67, respectively.
At this time, the other input section of the second AND circuit 67b is connected to the additional control section 61A. Therefore, even if the irradiation instruction signal input from the irradiation instruction switch 5 to one input section of the second AND circuit 67b is ON, if the irradiation permission signal is not input to the other input section, the irradiation instruction signal output from the second AND circuit 67b to the radiation control console 41 remains OFF.

When the additional device 6A detects that the irradiation instruction signal from the irradiation instruction switch 5 has been turned ON, it turns ON the imaging start signal to be output to at least one of the console 4 and the imaging device 3 (steps S23, S24).
At this time, the additional control unit 61A or the console 4 may check again the following determination conditions (1) to (3).
(1) The set irradiation frame rate is a value corresponding to the generator. (2) The set photographing frame rate is a value corresponding to the photographing device 3. (3) The irradiation frame rate: photographing frame rate = 1:N (where N is an integer equal to or greater than 1) (the photographing frame rate is N times the irradiation frame rate).
If the above relationship is not satisfied, the console 4 may prohibit progression to the following sequence or may not issue permission to shoot.
Furthermore, when taking the above measures, the photographer may be notified of an error, and a warning may be given to the photographer that the above relationship is not satisfied.

When the photographing device 3 detects that the photographing start signal has been turned ON, it turns ON the irradiation start signal to be output to the additional device 6A (step S25), as shown in Figure 15, for example, as a trigger for the end of the readout operation that it is performing at that time.
When the additional control unit 61A detects that the irradiation start signal from the photographing device 3 has been turned ON, it determines that the photographing device 3 is in a state where photographing is possible, and repeatedly inputs an irradiation permission signal to the other input section of the second AND circuit 67b of the I/F unit 67 each time it sends a timing signal to the photographing device 3.
At this time, the irradiation instruction signal from the irradiation instruction switch 5 and the irradiation permission signal from the additional control unit 61A, which are input to the second AND circuit 67b of the I/F unit 67, are both ON, so that the second AND circuit 67b repeatedly transmits the irradiation instruction signal to the radiation control unit 11A via the radiation control console 41 (step S26A).

When the irradiation frame rate: shooting frame rate is set to 1:N, the additional control unit 61 outputs a shooting permission signal once every N times it outputs a timing signal (Figure 5 shows the case where N = 2).
The imaging device 3 continues to repeat accumulation and readout, and every N times accumulation and readout are repeated, radiation is irradiated from the generator once to generate an exposure image.

The latter half of the operation in "D: Shooting execution" (steps S27 to S30) and the first half of the operation in "E: Shooting end" (steps S31 to S36) are the same as in the first embodiment.

[End of filming]
When the photographer confirms that shooting is completed, he or she opens the second stage of the irradiation instruction switch 5 (step S37), which turns the irradiation instruction signal OFF (step S38A). Then, the photographing device 3 turns the shooting start signal OFF.

Thereafter, when the photographer releases the first step of the irradiation instruction switch 5 (step S40), the irradiation instruction switch 5 turns off the irradiation preparation signal (step S41A).
Steps S43 to S45 are similar to those in the first embodiment.
Thus, a series of photographing operations is completed.
The system 200 according to this embodiment operates as described above, and as a result, like the system 100 according to the first embodiment, dynamic imaging is performed in which a plurality of still images are repeatedly captured in a short period of time.

[effect]
As described above, in the system 200 according to this embodiment, the radiation control device 1 can output an irradiation signal multiple times in response to one irradiation instruction (pressing the irradiation instruction switch 5 to the second level) by connecting the additional control unit 61A to the radiation control device 1 which can irradiate radiation only once in response to one radiation irradiation instruction in the conventional system 200A shown in Fig. 12. This makes it possible to perform imaging in which still images are repeatedly captured multiple times in a short period of time using the imaging device 3, i.e., dynamic imaging.
12 is widely used as a system capable of taking simple still images, and therefore medical institutions using the conventional system 200A can easily modify the conventional system 200A including the existing generator into one capable of dynamic imaging by simply adding the imaging device 3 and the additional device 6A, without updating the expensive generator.

In addition, in the system 200 according to this embodiment, the additional device 6A can be divided into an additional control unit 61A and an I/F unit 67, and the additional control unit 61A can be structured the same as the additional control unit 61 of the first embodiment (only the stored programs are different). Therefore, both the additional device 6 of the first embodiment and the additional device 6A of the second embodiment can be manufactured using common parts without increasing the number of types of devices (both the conventional system 100A and the conventional system 200A can be modified).

In addition, the system 200 according to this embodiment is configured to notify the photographer of the result of determining whether the imaging frame rate acquired by the console 4 is N times the acquired irradiation frame rate (where N is an integer equal to or greater than 1) in a manner that is recognizable to the photographer. This reliably prevents the risk of imaging being started with a frame rate that is not compatible with at least one of the imaging device 3 and the generator when imaging is performed in which the generator irradiates radiation less than the predetermined number of times while the imaging device 3 repeats charge accumulation and readout a predetermined number of times.

In the above description of the second embodiment, the configuration in which the additional device 6A is added to the conventional system 200A shown in Fig. 12 so as to enable dynamic imaging has been described. However, the embodiment of the present invention is not limited to this, and for example, the additional device 6A of the second embodiment can be added to the conventional system 100A shown in Fig. 1 so as to enable dynamic imaging.
This makes it possible to configure the conventional system 100A shown in FIG. 1 as a radiation imaging system according to the present invention, for example, by making the irradiation permission signal input to the radiation control unit 11 of the conventional system 100A shown in FIG. 1 always ON.
With this configuration, dynamic imaging can be made possible by adding additional devices to various types of radiation imaging systems.

In the above description of the first and second embodiments, the functions of the first acquisition means, second acquisition means, discrimination means, notification means or output means, irradiation permission means, read instruction means, and designation means of the present invention, which have been described as being possessed by the additional control unit 61 or the console 4, as well as various functions associated with these functions, may be possessed by the radiation control device 1 or the imaging device 3, rather than by the additional control unit 61 or the console 4.

Furthermore, the systems 100 and 200 according to the first and second embodiments have been described above as examples in which the conventional systems 100A and 200A have been modified using the additional devices 6 and 6A. However, the present invention is not limited to such a form of radiation imaging system, and may be a radiation image system in which the imaging device 3 and the radiation control devices 1 and 1A are each provided with a dynamic imaging function without including the additional devices 6 and 6A.
In this case, the functions of the first acquisition means, second acquisition means, discrimination means, notification means or output means, irradiation permission means, read instruction means, and designation means in the present invention, as well as various functions associated with these functions, will be possessed by the console 4, the radiation control device 1, or the imaging device 3, etc.

<Sequence state transition>
Next, the sequence state transition operations of the systems 100 and 200 according to the first and second embodiments will be described with reference to FIGS.

[Premise, Background, Issues]
In the systems 100 and 200 according to the first and second embodiments, unless the connected devices operate in the correct order, shooting cannot be performed correctly.
Furthermore, even if an error unintended by the photographer occurs, such as noise in the signal line or a disconnection of the signal line, it is necessary to safely end the imaging and prevent unintended radiation exposure, etc. from occurring.

[motion]
First, a description will be given of the operation of the systems 100 and 200. Fig. 17 is a state transition diagram of the systems 100 and 200, and Fig. 18 is a timing chart showing the operation of the systems 100 and 200.

As shown in FIG. 17, the systems 100 and 200 according to this embodiment are initially in a standby state St1 in which no instruction to start shooting has been received from the photographer.
Thereafter, the console 4 receives an imaging order from a higher-level system 7 such as a RIS or HIS. When the photographer selects an imaging order, the console 4 turns on a sequence start signal to be output to the imaging device 3 and the additional devices 6 and 6A (t1), as shown in FIG. 18 .
Then, the imaging device 3 and the additional devices 6 and 6A start preparation for imaging, whereby the systems 100 and 200 transition to the irradiation preparation state St2 as shown in FIG.

In the irradiation preparation state St2, as shown in FIG. 18, the additional device 6, 6A repeatedly transmits a timing signal to the photographing device 3 at a predetermined interval, and each time the photographing device 3 receives this timing signal, the photographing device 3 repeats a read operation, thereby repeatedly performing a reset operation to remove the electric charge accumulated in the photographing device 3.
The read operation performed here is the same as the operation performed when acquiring a photographed image. However, since the image acquired by the reset operation was generated in the irradiation preparation state St2 in which radiation is not being irradiated, the image may be saved in the memory of the imaging device 3 or transferred to the console 4, or may be deleted without being saved or transferred.

On the other hand, at least a portion of the image acquired by this reset operation can be stored in the imaging device 3 or transferred to the console 4, for example, as a correction image for correcting the captured image, in order to represent the characteristics of individual pixels of the imaging device 3 or the image of the imaging device 3.
The correction image may be at least one of the multiple images obtained by repeating the reset operation, or the average of the signal values of corresponding pixels in the multiple images, or a complementary predicted value in the time direction may be calculated and used as the correction image.
A method for correcting a captured image includes subtracting the signal value of each pixel of a correction image from an image obtained by irradiating radiation.

The timing signal may be configured to be sent to the imaging device 3 even when the imaging device 3 is in a state other than the irradiation preparation state St2, and the reset operation instruction signal may be turned ON when the imaging device 3 transitions to the irradiation preparation state St2, so that the imaging device 3 performs the reset operation only when the reset operation instruction signal is ON.

The operator sets the imaging conditions and the like using the imaging apparatus control console 42 or the radiation control console 41, and performs positioning of the subject before commencing imaging operations.
Specifically, as shown in Fig. 18, the irradiation instruction switch 5 is operated to turn on the irradiation preparation signal to be transmitted to the console 4 (t2), whereupon the system 100, 200 transitions to the irradiation start-up state St3 as shown in Fig. 17.

In the irradiation startup state St3, the console 4 checks the status of the radiation control device 1, the imaging device 3, and the additional devices 6, 6A, and if it determines that imaging is possible, turns on the imaging preparation completion signal to be sent to the additional devices 6, 6A (t3), as shown in Figure 17.
Here, the console 4 may be configured to check whether the shooting conditions set in the radiation control console 41 and the shooting conditions set in the shooting device control console 42 are the same or not, and if they are different, to display that fact.
In addition, if the shooting conditions set in the radiation control console 41 are different from the shooting conditions set in the shooting device control console 42, the configuration may be such that control is performed so as not to proceed to the subsequent shooting sequence.
Also, while the imaging preparation completion signal is ON, the imaging conditions set in the imaging apparatus control console 42 and the radiation control console 41 may be controlled so that they cannot be changed.

On the other hand, when the radiation control device 1 detects that the irradiation preparation completion signal is ON, it starts preparing to irradiate radiation (t2). This is, for example, an operation to start the rotation of the rotating anode of the radiation generating unit 2.

Furthermore, when the additional device 6, 6A detects that the irradiation preparation signal has been turned ON, the additional device 6, 6A starts counting the set timer (t2).
As will be described in detail later, this means that even if the photographer presses the second stage of the irradiation instruction switch 5 (turns the irradiation instruction signal ON), the camera cannot transition to an irradiation standby state St4 (described later) until the count of this timer has reached a predetermined standby time.

Thereafter, the photographer presses the second stage of the irradiation instruction switch 5 to turn on the irradiation instruction signal (t4). Note that, although Fig. 18 illustrates an example in which the irradiation instruction signal is turned on after the imaging preparation completion signal is turned on, the irradiation instruction signal may be turned on before the imaging preparation completion signal is turned on.
When the additional control unit 61, 61A confirms that the irradiation instruction signal is ON, that the shooting preparation completion signal is ON, and that the timer has elapsed a predetermined waiting time, the system 100, 200 transitions to the irradiation waiting state St4 as shown in Figure 17.

In the irradiation standby state St4, the additional control units 61 and 61A check whether the imaging device 3 is in an imaging-enabled state. The imaging device 3 checks whether it is in an imaging-enabled state, and when it is determined that it is in an imaging-enabled state, it transmits an irradiation start signal to the additional control units 61 and 61A (t5) as shown in FIG.
Whether or not photography is possible is confirmed by, for example, judging whether a specified reset operation has been completed and the electric charge in the light receiving section of the imaging device 3 has been removed, or whether the reset operation has been completed for all pixels on the light receiving surface (because the reset operation is performed by scanning each pixel arranged in a matrix on the light receiving surface, row by row).
When the additional control units 61 and 61A detect that the irradiation start signal from the imaging device 3 is ON, the states 100 and 200 transition to the irradiation permission state St5 as shown in FIG.

In the irradiation permission state St5, as shown in FIG. 18 , the additional control unit 61, 61A turns on the imaging start signal, which is an internal interlock (t5), and repeatedly transmits an irradiation permission signal or an irradiation instruction signal to the radiation control unit 11, 11A at a timing corresponding to the timing of outputting a timing signal to the imaging device 3.
The generating device (radiation control units 11, 11A, high voltage generating unit 12, radiation generating unit 2) generates radiation each time it receives an irradiation permission signal or an irradiation instruction signal, and the radiation that has passed through the subject can be repeatedly incident on the imaging device 3.

In the irradiation permission state St5, after the irradiation start signal is turned ON, the additional control unit 61, 61A may be configured to control so as to count the number of captured images each time it transmits a timing signal or an irradiation permission signal. In this case, when the counted number of captured images reaches a set maximum number of captured images, the imaging start signal is turned OFF (t6), and the system 100, 200 transitions to the irradiation end state St6 as shown in FIG.
In addition, when counting the number of captured images by counting the irradiation permission signal, since it is necessary to read out the captured image by the last radiation irradiation, the timing of turning off the read command signal can be delayed and a timing signal that triggers the read operation can be transmitted for one more frame. With such a configuration, it is possible to eliminate the risk of continuing imaging beyond the set maximum number of images, irradiating the subject with unnecessary radiation, and exposing the subject to more radiation than necessary.

Thereafter, when the photographer opens the second stage of the irradiation instruction switch 5, the irradiation instruction signal is turned OFF (t7), as shown in FIG.
Thereafter, when the photographer releases the first stage of the irradiation instruction switch 5, the irradiation preparation signal is turned OFF (t8).
Then, when the additional control unit 61, 61A confirms that all signals input to it have been released, the system 100, 200 transitions to the irradiation preparation state St2 as shown in FIG.
Here, "all signals" can be the irradiation preparation signal, the irradiation instruction signal, the imaging start signal which is an interlock of the additional control units 61 and 61A, and the irradiation start signal of the imaging device 3.

Thereafter, if the photographer performs further imaging, or if, after checking the captured images, he or she determines that the acquired images are not sufficient for the desired purpose and that re-imaging is necessary, the subject's condition or imaging conditions are changed and imaging is performed again following the above-described procedure.
On the other hand, if it is determined that imaging is not necessary, the console 4 turns off the sequence start signal (t9) to end the imaging sequence. Then, the system 100, 200 transitions to the standby state St1 as shown in FIG.
In addition to the above case (judgment by the photographer), a configuration may also be adopted in which the state transitions to the standby state St1 when there is no input from the photographer for a certain period of time.

[Action when not continuing shooting]
The above-described state transition flow is for the case where shooting continues until the maximum number of shots is reached, but there are cases where shooting cannot continue until the maximum number of shots is reached due to various circumstances.

For example, if the photographer wants to stop shooting before taking the maximum number of shots, the second stage of the irradiation instruction switch 5 is opened to turn off the irradiation instruction signal. This causes the system 100, 200 to transition from the irradiation permission state St5 to the irradiation end state St6. This occurs when one of the multiple OR conditions for transitioning from the irradiation permission state St5 to the irradiation end state St6 shown in FIG. 17 (the irradiation instruction signal from the irradiation instruction switch 5 is turned off, the irradiation start signal from the imaging device 3 is turned off, and the imaging start signal from the additional device 6, 6A is turned off) is met.

In the irradiation end state St6, the radiation irradiation is stopped, and thereafter, similarly to the case where the maximum number of images have been taken, processes such as transferring the remaining images in the imaging device 3 to the console 4 and deleting the images stored in the imaging device 3 after transfer are performed. This is because, even if the previously specified number of images have not been taken, there are cases where the captured images can be used, and even in such cases, the photographer can check the captured images in the same way as normal images.
On the other hand, it is necessary to link the fact that the predetermined number of shots was not taken to the captured images and manage them accordingly. If the predetermined number of shots was not taken, a configuration can be used in which a note is added to each individual image or group of images to indicate that the predetermined number of shots was not taken and the images are managed accordingly.
In addition, the console 4 may be configured such that, if the predetermined number of shots is not taken, an error signal is sent from the additional device 6, 6A to indicate that the predetermined number of shots has not been taken.

[Action when an error occurs]
There may also be cases where the connection between the additional device 6, 6A and the photographing device 3 is cut off during photographing. Possible causes for this include, for example, when the additional device 6, 6A and the photographing device 3 are connected by wire, the cable coming off the connector, and when the additional device 6, 6A and the photographing device 3 are connected wirelessly, possible causes include wireless interference, a wireless device malfunction, or power cut to the wireless device.

Therefore, systems 100 and 200 may be provided with a function for monitoring whether or not an error (Error 1, Error 2, Error 3, Error 4) has occurred in each of sequence states St3 to St6, and if an error is detected, the system may transition to error state St7 as shown by the dashed line in Figure 17.
In addition, when the state transitions to the error state St7, the display unit 43 of the console 4 may be configured to display the type of error that caused the state transition to the error state St7.

Such error detection may be performed, for example, by running an error monitoring sequence that monitors signals in each state in parallel with the shooting sequence shown in Figure 17, and if an error is detected in the error monitoring sequence, the shooting sequence may be transitioned from the current sequence state St3 to St6 to an error state St7.
Alternatively, an operable time may be set for each of the sequence states St3 to St6 shown in FIG. 17, and the operating time in each sequence state may be measured by starting a timer when transitioning to each of the sequence states St3 to St6, and the transition to the error state St7 may be controlled when the timer time has elapsed since the operable time for that sequence state.
Furthermore, when an error occurs, the additional device 6, 6A or the image capturing device 3 that detects the error may notify the console 4 of the error, and the console 4 may display the occurrence of the error.

After transitioning to the error state St7, the state will transition to the irradiation preparation state St2 or the standby state St1 when a specific condition is met (such as clearing the error or clearing all signals).

[effect]
By using such an error detection method, it is possible to reliably detect malfunctions in the device or operation, transition to an error state, and, if necessary, return to the standby state St1 or the irradiation preparation state St2 from the middle of the shooting sequence, thereby eliminating the risk of radiation being irradiated while there is a malfunction in the device or operation, resulting in unnecessary exposure of the subject to radiation.

Next, a specific example of implementing the above systems 100 and 200 will be described.
It should be noted that the various techniques described here may also be applicable to the conventional systems 100A and 200A.

Example 1
[Standardization of shooting operations for low and high frame rates]
If the operation of the photographing device 3 differs depending on the set photographing frame rate, there is a problem that when photographing dynamic images, the photographed image obtained a predetermined time after the start of photographing differs between photographing at a high frame rate and photographing at a low frame rate.
For example, when shooting at a high frame rate and when shooting at a low frame rate, the number of frames shot within a certain time period from the start of shooting differs, which causes a problem that the temperature change and the like in the shooting device 3 accompanying the shooting operation differs between shooting at a high frame rate and shooting at a low frame rate, resulting in images of different quality.
This can be problematic, for example, when observing the progress in size of a region of interest such as a tumor in detail by taking images at a high frame rate immediately after surgery, and then taking images at a low frame rate to reduce radiation exposure when checking the postoperative progress. If the images change due to differences in shooting modes, it becomes difficult to compare the postoperative progress with that immediately after surgery.

In view of such a problem, when imaging is performed by changing the irradiation frame rate, the imaging frame rate set in the imaging device 3 may not be changed. In other words, even if the radiation irradiation cycle of the generator is expanded, the imaging device 3 is made to repeat the imaging operation at the same cycle. In this case, when imaging is performed in a low frame rate mode, unexposed frames are extracted from the captured frames, and a dynamic image is generated consisting of the extracted unexposed frames.
In this way, the effects of temperature rise and the like after a predetermined time has elapsed since the start of imaging become the same, so images of the same quality can be acquired at the same temperature even with different irradiation frame rates.

Example 2
[Changes in radiation exposure period]
The imaging device 3 creates an image by sequentially reading out the exposure image generated at the timing of radiation irradiation, starting from the pixels at the end of the radiation detection unit 32. If radiation is partially irradiated during sequential reading out from the pixels at the end, part of the radiographic image generated by this reading out may become part of the image of the next frame, and therefore the radiation irradiation time is limited to a period during which the imaging device 3 is not reading out.
However, the radiation exposure window, which is the period during which radiation can be irradiated, becomes shorter when the frame rate is high, making it difficult to complete radiation exposure within the radiation exposure window. In particular, with pulsed radiation exposure, there is a wave tail where radiation remains in the latter half of the pulse, making it difficult to fit the entire exposure, including the wave tail, within the radiation exposure window.

In view of such problems, the length of the radiation irradiation window may be changed depending on whether or not thinning-out irradiation is performed, as shown in Fig. 19. In particular, when thinning-out irradiation is performed, the radiation irradiation window may be made longer than when thinning-out irradiation is not performed, as shown in Fig. 19(b).
This allows for a sufficient time between the rising edge and the falling edge of the pulsed radiation, making it easier to keep the wave tail of the radiation within the radiation irradiation window.
In addition, when thinning-out irradiation is performed, even if the wave tail does not fit within the radiation irradiation window, it is erased when the next thinned image is read in, so even if the radiation irradiation time is extended, there is no effect on the frame in which the next radiation exposure is captured.

Example 3
[Change transfer period]
In dynamic image capture, after an image is read out, the transfer of the image may not be completed before the next accumulation, which poses a problem.
In view of this problem, images generated at a timing when radiation is not irradiated may not be transferred, but may be stored in the imaging device 3 or deleted from the imaging device 3.
Then, for example, as shown in FIG. 20, the transfer of an image generated at the timing of radiation irradiation is performed by using at least a part of the accumulation/readout period at the timing of radiation not being irradiated.
In this way, the transfer time of the image generated at the timing of radiation irradiation can be increased, and the image can be transferred stably.
It also makes it possible to increase the overall frame rate.

Example 4
[Control of shooting timing (1)]
When photographing is performed during a portion of the irradiation instruction signal input period, if the period from when the photographer presses the second stage of the irradiation instruction switch to when photographing actually starts is long, there is a problem that the photographer may not be able to photograph the movement he or she wants to capture.
In view of these problems, when photographing is performed during a portion of the irradiation instruction signal input period, photographing (irradiation and accumulation of radiation) may be performed at the timing when the first image can be photographed after the photographer issues a photographing instruction, as shown in FIG. 21, for example.
In this way, since shooting is performed as early as possible after the photographer issues a command to shoot, shooting can be started at the timing the photographer desires, and the risk of not being able to capture the movement that the photographer desires can be reduced.

Example 5
[Control of shooting timing (2)]
Before starting image capture, the image capture device 3 needs to be reset and warmed up, and in order to obtain a stable image, it is sometimes preferable to start image capture as late as possible.
In view of such problems, when photographing is performed during a portion of the irradiation instruction signal input period, photographing may be performed from another photographing timing from the second photograph onwards, rather than from the timing at which the first photograph can be taken after the photographer issues a photographing command, as shown in FIG. 22, for example.
For example, when performing imaging such that the generator irradiates radiation once every time the imaging device 3 performs an N-time imaging operation (N=2 in the case of FIG. 22), imaging is performed at the Nth possible timing after the photographer issues an instruction to perform imaging.
In this way, photographing can be performed at a later timing after the photographer issues an instruction to photograph, allowing the photographing device 3 to perform sufficient resetting and warming up, etc., and to start photographing in a stable state, thereby improving the quality of the photographed image.

Example 6
[Waiting time before shooting starts]
Before starting image capture, the image capture device 3 needs to be reset and warmed up, and in order to obtain a stable image, it is sometimes preferable to start image capture as late as possible.
In consideration of such problems, at least one of the imaging device 3, the additional control unit 61, the console 4, and the radiation control unit 11A may be provided with a delay time so that the imaging operation begins a predetermined time after the first or second stage of the irradiation instruction switch is pressed.
When shooting in the dynamic image shooting mode, the delay time may be set longer than when shooting in the still image shooting mode.
Alternatively, radiation may be irradiated several times in the initial stage of the imaging operation to stabilize the radiation before starting image generation. In this case, the imaging device 3 may not perform imaging during the initial stage of radiation irradiation.

Furthermore, in order to prevent radiation from being irradiated to the subject during the initial stage of radiation irradiation several times, radiation emission may be suppressed by the radiation generating unit or its periphery, or a collimator associated with the radiation generating unit 2. As a method for suppressing radiation, for example, a suppression plate or the like that is difficult for radiation to transmit is movably arranged on the radiation generating unit 2 or its periphery, or a collimator associated with the radiation generating unit 2, and during the initial stage of radiation irradiation several times, the suppression plate or the like is moved onto the radiation irradiation axis to block radiation generated from the radiation generating unit 2 with the suppression plate or the like to suppress irradiation of the surroundings. After the initial stage of radiation irradiation several times, the suppression plate or the like is moved away from the irradiation axis, making it possible to irradiate the subject with radiation after the initial stage and to image the subject.
In this way, photographing can be performed at a later timing after the photographer issues an instruction to photograph, allowing the photographing device 3 to perform sufficient resetting and warming up, etc., and to start photographing in a stable state, thereby improving the quality of the photographed image.

(Example 7)
[Method of capturing the amount of change]
Some imaging techniques focus on the amount of change in dynamics at a certain point in time. For example, when imaging blood flow, it is not necessary to repeat imaging over a long period of time, and it is sufficient to obtain multiple consecutive images (two or more) at the moment when the blood flow is to be imaged.
However, if it is not possible to acquire only the pre- and post-images at the required timing (if imaging must be repeated at the same timing), the subject will be unnecessarily exposed to radiation.
In view of such a problem, only the necessary photographing may be performed at a timing when the amount of change is required or at a timing when only a plurality of consecutive photographed images are required.
For example, as shown in FIG. 23, the imaging device 3 is made to repeatedly store and read out at a fixed cycle, and the generator is made to irradiate radiation only at the timing of imaging a series of multiple consecutive images.

In this way, by comparing multiple consecutive captured images obtained by irradiating this radiation, it is possible to obtain the amount of change in the subject's condition over a specified period of time including the time when a particular captured image was taken.
For example, when photographing blood flow, it is possible to grasp the blood flow at the photographing timing by taking a number of consecutive images at a specific timing and analyzing the changes in those images as shown in Fig. 23. In addition, it is possible to observe the continuous blood flow state by grasping the blood flow state at the photographing timing from the difference between the consecutive images.
23, the amount of change between the first and second images is obtained by capturing two consecutive images, but it is also possible to calculate the amount of change between the first and second images by capturing three or more images at appropriate times. Calculating the amount of change from capturing three or more images makes it possible to keep noise and the like low.
Furthermore, unlike the case shown in FIG. 23, if radiation were to be irradiated at all timings when the imaging device is in an accumulation-enabled state, the subject would be exposed to twice the amount of radiation exposure necessary. However, as shown in FIG. 23, by thinning out radiation irradiation at unnecessary timings, it is possible to reduce the amount of radiation exposure while obtaining necessary information.

(Example 8)
[Variable Frame Rate]
Depending on the imaging technique, the required frame rate may change during imaging.
However, in the conventional imaging device 3, since it was difficult to change the imaging frame rate midway, it was necessary to accumulate and read out at a constant imaging frame rate and irradiate radiation at a constant irradiation frame rate, which resulted in irradiation of radiation even in unnecessary frames, resulting in unnecessary exposure of the subject to radiation.
In view of such a problem, for example, as shown in FIG. 24, the interval for thinning out may be changed at any timing during shooting.
At that time, the imaging device 3 may be set to perform imaging at a constant imaging frame rate. After that, by selecting only the images captured at the timing when radiation is irradiated, it becomes possible to obtain images captured at a different frame rate.

This makes it possible to use a conventional imaging device 3 designed to match the inherent frame rate. The imaging device 3 that captures images at such an inherent frame rate can be started up more quickly and can continue to capture images stably, compared to a special imaging device that can change the frame rate.
Furthermore, by changing the timing of thinning out radiation irradiation during imaging, it becomes possible to perform radiation imaging only at the required frame rate, thereby preventing the subject from being unnecessarily exposed to radiation.

Example 9
[Control by external signal]
The timing to start imaging and the timing to change the frame rate are determined by the motion of the subject and the operation of the imaging device and imaging system. For example, in an imaging technique such as tomosynthesis described later, which requires changing the timing to start imaging and the frame rate depending on the operating state of the radiation generating unit, the timing must be changed depending on the operation of the imaging system.
However, it is difficult for an operator to appropriately determine the timing to start imaging or change the frame rate while monitoring the subject's behavior and the operation of the imaging device and imaging system. For this reason, it has been desired to be able to start imaging or change the frame rate by utilizing a measuring device that quantitatively measures the behavior or a detection means that detects the start of a predetermined operation of the imaging device 3.
In view of such a problem, it is also possible to start shooting using an external trigger, or to change shooting conditions such as changing the frame rate.
As the external trigger, for example, a heart rate monitor attached to the subject, an auto voice that instructs the subject's movements, a signal from the radiation control device 1 that controls the tube operation, etc. can be used.
In this way, by utilizing a measuring device that quantitatively measures dynamics and a detection means that detects the start of a specified operation of the imaging device 3, it is possible to start imaging at an appropriate time or change the frame rate.

Example 10
[Application examples to tomosynthesis, etc.]
In an imaging method such as tomosynthesis that generates a tomographic image by capturing images while moving the radiation generating unit 2 at a constant speed, there is little effect on the tomographic image when an image is captured in a state in which the radiation irradiation axis is largely inclined with respect to an axis perpendicular to the radiation entrance surface 3a of the imaging device 3. For this reason, in imaging that generates such a tomographic image, it may be desirable to reduce the imaging frame rate and make the imaging intervals shorter while the radiation irradiation axis is largely inclined.
On the other hand, when it is desired to obtain a detailed tomographic image, the influence of images captured when the radiation irradiation axis is largely inclined relative to the axis perpendicular to the radiation entrance surface 3 a is relatively large. Therefore, contrary to the above case, it may be desirable to set the shooting intervals densely when the radiation irradiation axis is largely inclined and to reduce the shooting frame rate and set the shooting intervals coarsely when the radiation irradiation axis is slightly inclined.
However, in conventional radiation imaging control devices, radiation is irradiated at equal intervals to perform imaging, which causes a problem of unnecessary exposure of the subject to radiation.
In view of such a problem, the irradiation frame rate may be changed according to the inclination of the irradiation axis of the radiation with respect to the radiation entrance surface, that is, the radiation may be thinned out as shown in FIG.

For example, if the shooting interval is made dense when the inclination of the radiation irradiation axis is large and the shooting interval is made sparse when the inclination is small, when the radiation generating unit 2 is located in region (A) of regions (A) to (E) shown in Figure 25 where the inclination of the irradiation axis is large, the irradiation frame rate is made high (this is set to the "no thinning (dense)" state in Figure 24), and when the radiation generating unit 2 is located in region (B) where the inclination of the irradiation axis is smaller than that of region (A), the irradiation frame rate is made low (this is set to the "thinning 1" state in Figure 24 (for example, radiation is thinned out every other time)). In addition, when the irradiation axis is in the (C) region where the inclination is smaller than in the (B) region, the irradiation frame rate is further lowered (this is set to the "thinning out 2" state in FIG. 24 (for example, two thinnings are performed for each irradiation of radiation)), and then, in the (D) region where the irradiation axis is inclined more than in the (C) region, the irradiation frame rate is increased (this is set to the "thinning out 1" state), and in the (E) region where the irradiation axis is inclined more than in the (D) region, the irradiation frame rate is further increased (this is set to the "no thinning out (dense)" state).

On the other hand, as described above, depending on the imaging method, it may be desirable to change the imaging interval so that the imaging interval is sparse when the inclination of the irradiation axis of radiation is large and the imaging interval is dense when the inclination is small. In such a case, when the radiation generating unit 2 is located in region (A) or (E) of regions (A) to (E) shown in FIG. 25 where the inclination of the irradiation axis is large, the same state as “thinning out 2” in FIG. 24 is used. When the radiation generating unit 2 is located in region (B) or (D) where the inclination of the irradiation axis is smaller than (A) or (E) (this state is referred to as “thinning out 1” in FIG. 24 ), the irradiation frame rate is increased. When the radiation generating unit 2 is located in region (C) where the inclination of the irradiation axis is smaller than (B) or (D), the irradiation frame rate is further increased (this state is referred to as “no thinning out (dense)” in FIG. 24 ).
In this way, it is possible to perform imaging with the amount of radiation required to generate a tomographic image without unnecessarily exposing the subject to radiation, thereby making it possible to reduce the amount of radiation exposure to the subject.

(Example 11)
[Application of Additive Readout (1)]
Depending on the imaging region and imaging technique, there are cases where a certain level of image resolution is required, and cases where high-speed imaging is desired in exchange for low image resolution.
In view of these issues, when the imaging device 3 reads out a radiological image, the imaging frame rate may be changed by changing the amount of additive readout (binning) of pixels arranged in at least one of the vertical and horizontal directions in the radiological image, thereby changing the imaging frame rate and performing imaging.
Specifically, when selecting the imaging area and imaging technique, the binning amount, imaging frame rate, and thinning degree N (setting the irradiation frame rate to 1/N of the imaging frame rate) are set according to the recommended amounts for the selected imaging device, and imaging is performed.
In this way, the additional device 6 and the console 4 which give instructions to the imaging device 3 function as the read-out instruction means of the present invention, making it possible to perform imaging at an appropriate resolution and frame rate according to the imaging area and imaging technique.
It is also possible to increase the number of imaging techniques that can be supported.

Example 12
[Application of Addition Readout (2)]
There are two methods for adding and reading out the electric charges accumulated in each pixel of the imaging device: (a) and (b) described below.
(a) Analog binning, which adds and reads out on the circuit (b) Digital binning, which reads out individually on the circuit and adds the read values later In order to speed up the shooting frame rate, it is effective to perform additive readout using analog binning, which can shorten the readout time. However, on the other hand, in cases where it is desired to switch between the presence and absence of binning after image shooting, or when analog binning is performed and added on the circuit before readout, and there is a possibility that the conversion range of the A/D converter 34c of the readout unit 34 of the shooting device 3 may be exceeded, it may be appropriate to use digital binning for at least a part of the additive readout.
In view of these issues, the imaging device 3 may be configured to use analog additive readout for additive readout of pixels arranged in one of the vertical and horizontal directions in the radiation image, and to use digital additive readout for additive readout of pixels arranged in the other direction.
In this way, the additional device 6 and the console 4 which give instructions to the imaging device 3 function as the read-out instruction means of the present invention, making it possible to perform imaging at an appropriate resolution and frame rate according to the imaging area and imaging technique.

In particular, the frame rate at which the image capturing device 3 can capture images may be increased by adjusting the direction and amount of analog binning or digital binning, thereby increasing the number of combinations of frame rates at which images can be captured.
For example, in a method such as tomosynthesis in which images are captured while moving the radiation generating unit 2 in a fixed direction and the image is reconstructed after capture, the resolution of pixels aligned in a direction perpendicular to the movement direction of the radiation generating unit 2 in the imaging device 3 may be more important than the resolution of pixels aligned in the movement direction, or conversely, the resolution of pixels aligned in the movement direction may be more important.
In such a case, it becomes possible to perform an imaging method in which pixels aligned in the direction of movement of the imaging device 3 are added using analog binning to speed up readout, and the binning amount is adjusted using digital binning for pixels aligned in a direction perpendicular to the direction of movement, or vice versa.

(Example 13)
[Image correction method (1)]
When the switch element 32e provided in each pixel of the image capture device 3 is turned off, each pixel is placed in a state in which electric charge can be accumulated, and when the switch element 32e is turned on, the accumulated electric charge is discharged.
When the shooting frame rate becomes high, the switch element 32e turns off before the charge accumulated in each pixel is completely discharged, and the charge that has not been completely discharged remains as an afterimage in the next image, which is a problem.
In view of this problem, an unexposed image generated at a timing when radiation is not irradiated may be used to correct an image having an afterimage (read efficiency correction).
Specifically, the read efficiency correction is performed according to the following formula (1). Details are described in, for example, JP 2017-192605 A.
Image after readout efficiency correction (x, y)={Image after gain correction (x, y)−Image after gain correction (x, y)_1 frame before×α(x, y)}/(1−a(x, y)) (1)
(Here, α is a correction coefficient (where 0<α<1), and (x, y) are coordinates within the image.)
Such read-out efficiency correction requires an image from one frame before, but by doing so, using an unexposed image for the correction, it is possible to prevent residual images caused by the operation of the switching element from remaining in the exposed image.

(Example 14)
[Image correction method (2)]
Even after the readout efficiency correction is applied to the unexposed image, an afterimage may remain. This afterimage is often caused by a time lag (a delay in charge generation, a lag component) when the photodiodes constituting the radiation detection elements 32d generate charges.
In view of this problem, the lag component remaining in the next exposed image may be predicted based on the time interval between the current unexposed image and the next exposed image, and subtracted from the next exposed image.
An unexposed image contains a lag component that occurs when an exposed image of the previous frame is generated, and the extent to which the lag component is contained in the next exposed image can be calculated from the attenuation characteristics.
In this way, it is possible to prevent residual images caused by lag components from remaining in the exposed image.

(Example 15)
[Image correction method (3)]
In order to suppress graininess and line noise in an image, a recursive filter process as expressed by the following formula (2) may be applied to the image.
Current frame processed image=α×previous frame processed image+(1−α)×current frame unprocessed image (2)
(where α is a correction coefficient (0<α<1))
However, when imaging a fast-moving subject, the difference in the subject's position between the pre-exposure frame and the current exposure frame becomes large, causing a problem in that an afterimage of the pre-processing image appears in the processed image.
In view of this problem, an unexposed image obtained immediately before the image to be corrected may be used in the recursive filtering process.
Line noise is independent of the amount of exposure and is present in both exposed and unexposed images to a certain extent. Therefore, by using the unexposed image recursively, the line noise can be averaged and reduced.
Furthermore, by using the immediately preceding unexposed image, graininess and line noise can be suppressed, and blurring is less noticeable even in the case of a fast-moving subject.

Note that if the subject moves significantly faster, blurring may be noticeable even when recursive filtering is performed using unexposed images as described above. Therefore, it is preferable to switch between using and not using recursive filtering depending on the thinning rate and the subject's movement.

(Example 16)
[Image correction method (4)]
A steady-state value X of an image after recursive filtering (when radiation is irradiated every other frame) is expressed by the following formula (3).
X = 1 / (1 + α) (3)
When the above-mentioned recursive filter processing is applied to dynamic images obtained by capturing images without performing thinning-out irradiation of radiation, a decrease in the steady-state value is observed in the first few frames, as shown in Figure 26, for example, but then returns to normal.
On the other hand, if the above-mentioned recursive filter processing is performed on a dynamic image obtained by capturing images while thinning out the radiation, the image after processing will repeatedly have low signal values.
For example, when the irradiation frame rate is half the imaging frame rate (radiation irradiation is thinned out every other frame), the steady-state value of the pre-processed image is 1, and the correction coefficient α is 0.2, the steady-state value X is 0.83.
In addition, when the irradiation frame rate is 1/4 of the imaging frame rate (radiation irradiation is thinned to three out of four frames), the steady-state value of the pre-processing image is 1, and the correction coefficient α is 0.2, the steady-state value X is 0.8.
In view of this problem, the steady-state value of the thinned image may be divided by the value of X.
By doing this, even if the steady-state value of the processed image decreases, it can be returned to 1.
Although specific calculation formulas are omitted here, this embodiment can also be applied to dynamic images obtained by imaging in which radiation is irradiated every N frames (with N-1 frames in between being unexposed).

(Example 17)
[Image correction method (5)]
Even after the unexposed image is subjected to the above-mentioned readout efficiency correction and the lag component is subtracted, a signal may remain. This signal is often caused by an increase in offset (offset drift) due to a rise in temperature of the readout section 34.
In view of such a problem, the offset drift component may be reduced by subtracting the average value, mode value, etc. of the amount of offset drift of the unexposed image before and after exposure from the exposed image.
In this way, it is possible to prevent signals resulting from offset drift components from remaining in the exposure image.

In the above embodiment, various image corrections using unexposed images have been described. However, when thinning-out irradiation of radiation is not performed, image processing is performed using exposed images, for example. That is, a predetermined image correction is performed on a radiation image captured in a state where the imaging frame rate set in the imaging device 3 is N times the irradiation frame rate set in the generator, and an image correction different from the above image correction is performed on a radiation image captured in a state where the imaging frame rate set in the imaging device 3 is equal to the irradiation frame rate set in the generator. Thus, the imaging device 3 and the console 4 in the above embodiment form the first image correction means and the second image correction means in the present invention.

100, 200 Radiation imaging system 100A, 200A Conventional radiation imaging system 1, 1A Radiation control device 11, 11A Radiation control unit 12 High voltage generating unit 2 Radiation generating unit 3 Radiation image imaging device 31 Imaging control unit 32 Radiation detection unit 32a Substrate 32b Scanning line 32c Signal line 32d Radiation detection element 32e Switch element 32f Bias line 32g Power supply circuit 33 Scanning drive unit 33a Power supply circuit 33b Gate driver 34 Readout unit 34a Readout circuit 34b Analog multiplexer 34c Converter 34d Integration circuit 34e Correlated double sampling circuit 35 Memory unit 36 Communication unit 36a Antenna 36b Connector 37 Battery 3A Cassette 4 Console 41 Radiation control console 42 Imaging device control console 43 Display unit 5 Irradiation instruction switch 6, 6A Additional device 61, 61A Additional control unit 62 First acquisition unit 63 Second acquisition unit 64 First connection unit 65 Second connection unit 66 Third connection unit 67 Interface unit 67a First AND circuit 67b Second AND circuit 7 Upper system 8A Supine position radiography stand 8B Upright position radiography stand 9 Communication device N Communication network St1 Waiting state St2 Irradiation preparation state St3 Irradiation start state St4 Irradiation waiting state St5 Irradiation permission state St6 Irradiation end state St7 Error state

The present invention relates to a radiography system .

Incidentally, before starting radiation imaging, the radiation imaging device needs to perform resetting, warming up, etc. Therefore, in order to obtain a stable image by performing sufficient resetting, warming up, etc., it is required to set the time from when an instruction to start radiation imaging (irradiation) is given to start the imaging operation to a time suitable for the imaging mode of radiation imaging.

An object of the present invention is to set the time from when an instruction to irradiate radiation is given to start an imaging operation to a more appropriate time .

In order to solve the above problems, the radiation imaging system according to the present invention comprises:
It is possible to take still images and dynamic images by repeatedly taking multiple still images.
The delay time, which is the time from pressing an irradiation instruction switch for instructing irradiation of radiation to starting an imaging operation, differs between the still image imaging and the dynamic imaging.

According to the present invention, the time from when an instruction to irradiate radiation is given until the start of imaging operation can be set to a more appropriate time .

Claims (10)

a first acquisition means for acquiring an irradiation frame rate, which is the number of times that a radiation generating device capable of repeatedly generating radiation at a predetermined cycle generates radiation per unit time;
a second acquisition means capable of acquiring an imaging frame rate, which is the number of times that a radiation image capturing device capable of repeatedly generating radiation images based on received radiation at a predetermined cycle generates a radiation image per unit time;
a determination means for determining whether the irradiation frame rate acquired by the first acquisition means is N times (where N is an integer equal to or greater than 1) the imaging frame rate acquired by the second acquisition means;
A radiation imaging control apparatus comprising: a notifying means for notifying a result of the discrimination made by the discriminating means in a manner that is recognizable by an operator; or an output means for outputting the discrimination result. The radiography control device according to claim 1, further comprising an irradiation permission means for permitting the radiation generating device to irradiate radiation when the determination means determines that the irradiation frame rate is N times the imaging frame rate. The radiation imaging control device according to claim 2, characterized in that the irradiation permission means permits the radiation generating device to irradiate radiation when the irradiation frame rate is 2 Hz or higher. The radiography control device according to any one of claims 1 to 3, characterized in that it is provided with a read instruction means capable of instructing the radiography device on the amount of added readout for pixels arranged in at least one of the vertical and horizontal directions in the radiography image when the radiography device reads out the radiography image. The radiography control device according to claim 4, characterized in that the read instruction means instructs the radiography device to use analog additive readout for additive readout of pixels arranged in one of the vertical and horizontal directions in the radiography image, and to use digital additive readout for additive readout of pixels arranged in the other direction. The notification means;
A designation means for designating a photographing condition,
The determining means performs the determination based on the photographing conditions designated by the designating means,
6. The radiation imaging control apparatus according to claim 1, wherein the notification means performs a display to notify the determination result. a radiation generating device capable of repeatedly generating radiation at a predetermined cycle;
a radiation image capturing device capable of repeatedly generating radiation images based on received radiation at a predetermined interval;
A radiation imaging system comprising: the radiation imaging control device according to claim 1 . a selection means for selecting a plurality of radiation images generated based on radiation irradiated from the radiation generating device from among a plurality of radiation images generated by the radiation image capturing device;
8. The radiation imaging system according to claim 7, further comprising: dynamic image generating means for generating a dynamic image having the plurality of radiation images selected by the selecting means as frames. a first image correction means for performing a predetermined image correction on a radiographic image captured in a state in which the imaging frame rate set in the radiographic image capturing device is N times the irradiation frame rate set in the radiation generating device;
9. The radiation imaging system according to claim 7, further comprising: a second image correcting means for performing image correction different from the image correction on a radiation image captured in a state in which the imaging frame rate set in the radiation image capturing device is equal to the irradiation frame rate set in the radiation generation device. setting an irradiation frame rate, which is the number of times radiation is generated per unit time, to a predetermined value in a radiation generating device capable of repeatedly generating radiation at a predetermined cycle;
setting an imaging frame rate, which is the number of times radiation images are generated per unit time, to a value N times the predetermined value in a radiation imaging device capable of repeatedly generating radiation images based on received radiation at a predetermined cycle;
a radiation generating device for repeatedly generating radiation at the set irradiation frame rate, and a radiation image capturing device for repeatedly generating radiation images at the set imaging frame rate, the radiation image capturing method comprising the steps of:

Images