Radiation generation control device, radiation generation control system, and radiography system

A radiation generation control device includes an acquirer, a first connector, a second connector and a controller. The acquirer acquires a first signal which instructs emission of radiation. The first connector inputs a second signal which indicates a driving state of a radiography apparatus that generates a radiographic image. The second connector connects with a radiation generation apparatus that generates radiation. The controller makes the second connector repeatedly output a third signal which instructs emission of radiation with a predetermined period based on the acquired first signal and the input second signal.

BACKGROUND

1. Technological Field

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

2. Description of the Related Art

The fluoroscopic techniques according to the related art which capture the images of the inside of a subject using radiation are mainly divided into a technique that captures a low-quality moving image using a camera and a technique that captures a high-quality still image using a film or a fluorescent plate.

As a means for capturing a moving image, for example, there is an X-ray imaging apparatus as disclosed in JP H09-270955 A which includes a TV camera that generates an X-ray transmission image and an X-ray high voltage device which applies a pulsed high voltage synchronized with an image acquisition operation of the TV camera to an X-ray tube while an irradiation switch is pressed.

In the field of still image capture, a new radiography apparatus (flat panel detector) has been developed which includes a substrate in which a plurality of pixels are two-dimensionally arranged and reads, as image data, the amount of charge generated in each pixel according to the intensity of radiation emitted from a radiation generation apparatus through a subject to capture a still image.

For example, JP 5203467 B2 discloses a technique which enables the radiography apparatus to be used instead of a film or a fluorescent plate in the existing radiography system.

In recent years, a radiography apparatus has been proposed which has an imaging capability to further improve the performance of the radiography apparatus and to repeatedly capture still images a plurality of times in a short time. In addition, an attempt has been made which repeatedly emits pulsed radiation to the radiography apparatus with a predetermined period to capture a series of still images of the dynamics of the part to be examined in the subject and applies the captured images to diagnosis. Hereinafter, the imaging which repeatedly generates still images in a short time is referred to as dynamic imaging.

However, in the existing X-ray imaging system described in JP 5203467 B2, even in a case where the radiography apparatus can be replaced with an apparatus corresponding to the dynamic imaging, a radiation generation apparatus can perform only one radiation emission operation in response to one radiation emission instruction. Therefore, it is difficult to perform dynamic imaging.

SUMMARY

An object of the invention is to provide a technique that can easily modify the existing radiation generation apparatus capable of performing only one radiation emission operation in response to one radiation emission instruction so as to respond to dynamic imaging.

To achieve at least one of the abovementioned objects, according to an aspect of the present invention, a radiation generation control device includes:

an acquirer that acquires a first signal which instructs emission of radiation;

a first connector that inputs a second signal which indicates a driving state of a radiography apparatus that generates a radiographic image;

a second connector that connects with a radiation generation apparatus that generates radiation; and

a controller that makes the second connector repeatedly output a third signal which instructs emission of radiation with a predetermined period based on the acquired first signal and the input second signal.

DETAILED DESCRIPTION OF EMBODIMENTS

Conventional Technology 1 which is the basis of first and second embodiments, the first embodiment, and the second embodiment will be described in this order. Then, Conventional Technology 2 which is the basis of third and fourth embodiments, the third embodiment, and the fourth embodiment will be described in this order.

Conventional Technology 1

First, Conventional Technology 1 which is the basis of a system100(will be described in detail below) according to the first embodiment of the invention will be described with reference toFIG. 1.

System Configuration

First, the schematic configuration of a radiography system (hereinafter, referred to as a conventional system100A) according to Conventional Technology 1 will be described.FIG. 1is a block diagram illustrating the conventional system100A.

As illustrated inFIG. 1, the conventional system100A includes, for example, a radiation controller11, a high voltage generator12, a radiation generator2, a cassette3A, a radiation control console41, and an irradiation instruction switch5and is configured to capture still images in which the radiation emission timing is not operatively associated with the imaging timing, using a radiographic film or CR.

FIG. 1illustrates a case where the radiation controller11and the high voltage generator12form a radiation control device1(for example, are accommodated in one housing). However, the radiation controller11and the high voltage generator12may be separately provided. For example, the radiation controller11and the high voltage generator12may be provided in different housings.

The radiation controller11, the high voltage generator12, and the radiation generator2form a radiation generation apparatus (hereinafter, referred to as a generation apparatus) according to the invention.

The radiation controller11is for controlling the emission of radiation.

Specifically, the radiation controller11can turn on an irradiation preparation signal to be output to the high voltage generator12or can control the irradiation preparation signal such that the irradiation preparation signal can be output to other external apparatuses, on the basis of the detection of the turn-on of the irradiation preparation signal from the radiation control console41.

In addition, the radiation controller11can control an irradiation instruction signal (first signal) for instructing the emission of radiation such that the irradiation instruction signal can be output to an external apparatus, on the basis of the detection of the turn-on of the irradiation instruction signal from the radiation control console41, and can transmit an irradiation signal corresponding to imaging conditions set by the radiation control console41to the high voltage generator12.

The irradiation preparation signal or the irradiation instruction signal that can be transmitted from the radiation controller11to an external apparatus is used, for example, in a case where the external apparatus is connected to the radiation controller11.

The irradiation preparation signal or the irradiation instruction signal enables the external apparatus to prepare imaging on the basis of the irradiation preparation signal or the irradiation instruction signal output from the radiation controller11in imaging in which the external apparatus other than the cassette3A is required at the time of the emission of radiation.

An example of the external apparatus is a grid rocking apparatus that is provided on a radiation incident surface of the cassette3A and is used to rock the grid in a case where imaging is performed.

Some of the external apparatuses have a configuration in which an irradiation permission signal is transmitted to the radiation controller11after preparation for imaging is completed. Therefore, the radiation controller11may include a connector for receiving the irradiation permission signal from the external apparatus and may transmit the irradiation signal to the high voltage generator12only in a case where both the irradiation instruction signal from the radiation control console41and the irradiation permission signal from the external apparatus are turned on.

In this case, the irradiation permission signal is not input to the radiation controller11before the imaging preparation of the external apparatus is completed. Therefore, it is possible to prevent radiation from being emitted before the imaging preparation of the external apparatus is completed.

For example, in a case where the external apparatus is the above-mentioned grid rocking apparatus, after the grid rocking apparatus starts rocking and reaches a designated rocking speed, the grid rocking apparatus may input the irradiation permission signal to the radiation controller11. In this configuration, in a case where the radiation controller11receives both the irradiation instruction signal from an irradiation instruction switch5based on an operation of a radiographer and the irradiation permission signal from the external apparatus, the radiation controller11outputs the irradiation signal first. Therefore, it is possible to prevent radiation from being emitted before the preparation of the external apparatus is completed.

In contrast, in a case where the radiation controller11does not want to use the irradiation permission signal from the external apparatus, for example, it is necessary to invalidate the irradiation permission signal or to keep the irradiation permission signal in an on or off state.

For example, in a case where the radiation controller11is configured to switch whether to use the irradiation permission signal from the external apparatus for determining whether or not the irradiation signal can be output, the switching may be invalidated such that the irradiation permission signal is not used for the determination.

In a case where the switching is not capable of being performed and, for example, the irradiation permission signal is configured to be instructed by opening or closing two signal lines, the two signal lines are always opened or closed to keep the irradiation permission signal in an on or off state.

Further, the radiation controller11may be configured not to transmit the irradiation signal until a predetermined standby time elapses after the detection of the turn-on of the irradiation preparation signal even if the turn-on of the irradiation instruction signal has been detected.

In this configuration, even in a case where the high voltage generator12or the radiation generator is configured to require some time for preparation after the turn-on of the irradiation preparation signal is detected, it is possible to prevent radiation from being emitted even through preparation for irradiation is not completed.

The high voltage generator12is configured to output an irradiation preparation output to the radiation generator2on the basis of the detection of the turn-on of the irradiation preparation signal from the radiation controller11.

In addition, the high voltage generator12is configured to apply, as an irradiation output, a high voltage (corresponding to the input irradiation signal) required for the radiation generator2to generate radiation to the radiation generator2, on the basis of the reception of the irradiation signal from the radiation controller11.

FIG. 1illustrates the configuration in which, when the high voltage generator12detects that the irradiation preparation signal from the radiation controller11has been turned on, the high voltage generator12transmits the irradiation preparation output to the radiation generator2. However, the invention is not limited thereto. For example, the radiation controller11may directly output the irradiation preparation signal to the radiation generator2and the radiation generator2may convert the irradiation preparation signal into the irradiation preparation output and prepare irradiation.

The radiation generator2(radiation tube) includes, for example, an electron gun and an anode and is configured to generate radiation (for example, X-rays) corresponding to the high voltage applied from the high voltage generator12.

Specifically, when the high voltage is applied, the electron gun emits electron beams to the anode and the anode receives the electron beams and generates radiation.

When radiation is generated, a portion that receives the electron beams generates heat and reaches a high temperature. Therefore, it is necessary to constantly change the position of the anode where the electron beams are emitted in order to stably emit the radiation. For this reason, in some cases, a rotating anode that emits electron beams while being rotated can be used.

The irradiation preparation output from the high voltage generator12can be used, for example, as a rotation start instruction of the rotating anode.

The cassette3A has a radiation film or a fluorescent plate provided therein and can form a radiographic image of a subject when radiation transmitted through the subject is incident.

The radiation control console41is configured to set information related to the subject or imaging conditions (for example, a tube voltage, a tube current, and an irradiation time) in the radiation controller11, using the connection of an information signal.

In addition, the radiation control console41may communicate with a host system7(for example, a radiology information system (RIS)) or a picture archiving and communication system (PACS); seeFIGS. 5 and 17) through the external communication network N such as a hospital LAN.

The irradiation instruction switch5is used by the radiographer to instruct the emission of radiation.

The irradiation instruction switch5according to this embodiment is configured to operate in two stages. Specifically, the irradiation instruction switch5is pressed to the first stage to turn on the irradiation preparation signal output to the radiation control console41and the irradiation instruction switch5is pressed to the second stage to turn on the irradiation instruction signal output to the radiation control console41.

FIG. 1illustrates the configuration in which the irradiation instruction switch5is connected to the radiation control console41, the irradiation preparation signal or the irradiation instruction output from the signal irradiation instruction switch5is input to the radiation controller11through the radiation control console41. However, the invention is not limited thereto. The irradiation instruction switch5may be connected to the radiation controller11such that the irradiation preparation signal or the irradiation instruction signal is directly input to the radiation controller11.

Operation

The operation of the conventional system100A will be described.

Irradiation Preparation Operation

If the radiographer presses the irradiation instruction switch5to the first stage, the irradiation instruction switch5turns on the irradiation preparation signal output to the radiation controller11through the radiation control console41.

If it is detected that the irradiation preparation signal has been turned on, the radiation controller11turns on the irradiation preparation signal output to the high voltage generator12and performs control such that the irradiation preparation signal can be output to the external apparatus.

If the high voltage generator12detects that the irradiation preparation signal has been turned on, it outputs the irradiation preparation output to the radiation generator2.

If the irradiation preparation output is input, the radiation generator2starts preparation for generating radiation.

The preparation for generating radiation indicates, for example, an operation of rotating a rotating anode in a case where the anode is the rotating anode.

Irradiation Operation

Then, if the radiographer presses the irradiation instruction switch to the second stage, the irradiation instruction switch5turns on the irradiation instruction signal output to the radiation controller11through the radiation control console41.

If it is detected that the irradiation instruction signal has been turned on, the radiation controller11performs control such that the irradiation instruction signal can be output to the external apparatus and transmits the irradiation signal to the high voltage generator12.

In addition, the radiation controller11transmits the irradiation signal to the high voltage generator12in the following case: the radiation controller11is configured to determine whether to emit radiation on the basis of the irradiation permission signal from the external apparatus; the irradiation instruction signal from the irradiation instruction switch5or the radiation control console41is in an on state; and the irradiation permission signal is received from the external apparatus.

If the irradiation signal is received, the high voltage generator12applies the high voltage required for the radiation generator2to emit radiation to the radiation generator2(performs irradiation output).

If the high voltage is applied from the high voltage generator12, the radiation generator2generates radiation corresponding to the applied voltage.

For example, the irradiation direction, irradiation region, and quality of the generated radiation are adjusted by a controller (not illustrated), such as a collimator, and the adjusted radiation is emitted to the subject and the cassette3A behind the subject. A portion of the radiation passes through the subject and is then incident on the cassette3A.

If the radiation is incident on the cassette3A, a radiographic image is formed on the film or the fluorescent plate provided in the cassette3A.

In a case where the timing when the irradiation preparation signal is turned on and the timing when the irradiation instruction signal are close to each other, for example, irradiation is performed before the rotation of the rotating anode of the radiation generator2reaches a sufficient speed and a local part of the rotating anode is excessively heated. As a result, the rotating anode is likely to be damaged or the amount of radiation emitted is likely to be unstable (for example, the amount of radiation is insufficient or excessive with respect to the irradiation intensity of the electron beams).

However, the above-mentioned configuration in which the radiation controller11does not to transmit the irradiation signal until a predetermined standby time elapses from the detection of the turn-on of the irradiation preparation signal even if the turn-on of the irradiation instruction signal has been detected makes it possible to prevent the occurrence of the above-mentioned problem.

As such, in radiography using the conventional system100A, only one radiographic image (still image) of the subject is captured on the basis of one imaging operation.

First Embodiment

A first embodiment of the invention will be described with reference toFIGS. 2 to 7. The same configurations as those in Conventional Technology 1 are denoted by the same reference numerals and the description thereof will not be repeated.

System Configuration

First, a system configuration of a radiography system (hereinafter, referred to as a system100) according to this embodiment will be described.FIG. 2is a block diagram illustrating the system100andFIG. 3is a block diagram illustrating a radiography apparatus3.

For example, the system100according to this embodiment differs from the conventional system100A in that the radiography apparatus (hereinafter, referred to as the imaging apparatus3) replaces the cassette3A and an imaging apparatus control console42and an additional apparatus6are added, as illustrated inFIG. 2.

The imaging apparatus3according to this embodiment includes, for example, an imaging controller31, a radiation detector32, a scanning driver33, a reader34, a storage35, and a communicator36, in addition to a housing (not illustrated) and a scintillator (not illustrated), as illustrated inFIG. 3. The components31to36are supplied with power from a battery37.

The housing is provided with, for example, a power switch (not illustrated), a changeover switch (not illustrated), an indicator (not illustrated), a connector36bof the communicator36which will be described below.

When the scintillator receives radiation, it emits electromagnetic waves having a longer wavelength than radiation, such as visible light.

The imaging controller31is, for example, a computer in which a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input/output interface are connected to a bus or a field programmable gate array (FPGA) which is not illustrated. In addition, the imaging controller31may be a dedicated control circuit.

The radiation detector32receives radiation and generates charge. The radiation detector32includes, for example, a substrate32a, a plurality of scanning lines32b, a plurality of signal lines32c, a plurality of radiation detection elements32d, a plurality of switching elements32e, a plurality of bias lines32f, and a power supply circuit32g.

The substrate32ais formed in a plate shape and is disposed so as to face the scintillator in parallel.

The plurality of scanning lines32bare provided so as to extend in parallel at predetermined intervals.

The plurality of signal lines32care provided such that they extend in parallel at predetermined intervals, extend in a direction perpendicular to the scanning line32b, and are not electrically connected to the scanning lines.

That is, the plurality of scanning lines32band the signal lines32care provided so as to form a lattice.

Each of the radiation detection elements32dgenerates an electric signal (current or charge) corresponding to the amount of radiation emitted to the radiation detection element (or the amount of light of electromagnetic waves converted by the scintillator) and is, for example, a photodiode or a phototransistor.

The plurality of radiation detection elements32dare provided in a plurality of regions partitioned by the plurality of scanning lines32band the plurality of signal lines32con a surface of the substrate32a. That is, the plurality of radiation detection elements32dare arranged in a matrix. Therefore, each radiation detection element32dfaces the scintillator.

A drain terminal of the switching element32ewhich is a switching element is connected to one terminal of each radiation detection element32dand the bias line is connected to the other terminal of the switching element32e.

The plurality of switching elements32eare provided in a plurality of regions partitioned by the plurality of scanning lines32band the plurality of signal lines32c, similarly to the radiation detection elements32d.

Each switching element32ehas a gate electrode that is connected to the neighboring scanning line32b, a source electrode that is connected to the neighboring signal line32c, and a drain electrode that is connected to one terminal of the radiation detection element32din the same region.

The plurality of bias lines32fare connected to the other terminal of each radiation detection element32d.

The power supply circuit32ggenerates a reverse bias voltage and applies the reverse bias voltage to each radiation detection element through the bias lines32f.

The scanning driver33includes, for example, a power supply circuit33aand a gate driver33b.

The power supply circuit33agenerates an on-voltage and an off-voltage which are different from each other and supplies the generated voltages to the gate driver33b.

The gate driver33bswitches the voltage applied to each scanning line32bto the on-voltage or the off-voltage.

The reader34includes, for example, a plurality of reading circuits34a, an analog multiplexer34b, and an A/D converter34c.

The plurality of reading circuits34aare connected to each signal line32cof the radiation detector32and apply a reference voltage to each signal line32c.

Each reading circuit34aincludes, for example, an integration circuit34dand a correlated double sampling circuit (hereinafter, referred to as a CDS circuit)34e.

The integration circuit34dintegrates the charge transmitted to the signal line32cand outputs a voltage value corresponding to the integrated amount of charge to the CDS circuit34e.

The CDS circuit34esamples and holds the output voltage of the integration circuit34dbefore the on-voltage is applied to the scanning line32bto which the radiation detection element32d, from which a signal is to be read, is connected (while the off-voltage is applied). After the on-voltage is applied to the scanning line32bto read signal charge from the radiation detection element and the off voltage is applied to the scanning line32b, the CDS circuit34eoutputs the difference between the output voltages of the integration circuit34d.

The analog multiplexer34boutputs a plurality of difference signals output from the CDS circuits34eone by one to the A/D converter34c.

The A/D converter34csequentially converts image data of the input analog voltage value into image data of a digital value.

The storage35is, for example, a static RAM (SRAM), a synchronous DRAM (SDRAM), a NAND flash memory, or a hard disk drive (HDD).

The communicator36includes an antenna36afor communication with the outside and the connector36b.

The communicator36can select one of wireless communication and wired communication on the basis of a control signal from the outside. That is, in a case where wireless communication is selected, the communicator36can perform wireless communication using the antenna36a. In a case where wired communication is selected, the communicator36can transmit and receive information using, for example, a wired LAN. In addition, in a case where the user wants to perform synchronization using wired communication, for example, it is possible to perform synchronization using a protocol, such as the Network Time Protocol (NTP), or a method defined by the international standard IEEE1588.

If power is turned on, the imaging apparatus3having the above-mentioned configuration is switched to one of an “initialization state”, an “accumulation state”, and a “reading and transmission state”. The timing when the state is switched will be described below.

In the “initialization state”, the on-voltage is applied to each switching element32eand the charge generated by the radiation detection element32dis not accumulated in each pixel (the charge is output to the signal line32c).

In the “accumulation state”, the off-voltage is applied to each switching element32eand the charge generated by the radiation detection element32dcan be accumulated in the pixel (the charge is not transmitted to the signal line32c).

In the “reading and transmission state”, the on-voltage is applied to each switching element32e, the reader34is driven to read image data based on the transmitted charge and can transmit the image data to other devices.

The accumulated charge is cleared by reading, depending on the configuration of the elements and the devices. Therefore, “reading” and “initialization” are not distinguished as separate operations and may be performed as the same operations at the same time.

In this embodiment, a so-called indirect type that converts the emitted radiation into electromagnetic waves with other wavelengths, such as visible light, to obtain an electric signal has been described as an example. However, the invention is not limited thereto. A so-called direct-type imaging apparatus may be used in which a detection element directly converts radiation into an electric signal.

In addition, other configurations of the imaging apparatus3do not need to be limited to those illustrated inFIG. 3as long as they can generate the image data of the radiographic image.

As illustrated inFIG. 2, the imaging apparatus control console42is configured to transmit and receive an information signal to and from a radiation control console41and to set, for example, information related to the subject or imaging conditions in the imaging apparatus3.

The radiation control console41performs setting for the radiation controller11and the imaging apparatus control console42performs setting for the imaging apparatus3. However, since both the radiation control console41and the imaging apparatus control console42perform setting related to the same imaging operation, they may be collectively referred to as a console4in a broad sense in the following description.

The console4and the additional apparatus6form a radiation generation control system according to the invention.

In addition,FIG. 2illustrates the configuration in which the imaging apparatus control console42sets, for example, imaging conditions in a radiation controller11through the radiation control console41(the radiation control console41and the imaging apparatus control console42transmit and receive information signals). However, the imaging apparatus control console42may directly perform setting for the radiation controller11.

Further, the radiation control console41may perform setting for the imaging apparatus3.

FIG. 2illustrates the configuration in which the console4is connected to the imaging apparatus3through the additional apparatus6. However, for example, the console4may be directly connected to the imaging apparatus3or may be connected to the imaging apparatus3through a communication network N as illustrated inFIG. 2.

Further, the console4may set the operation of the additional apparatus6.

Specifically, it is possible to set, in the additional apparatus6, the number of times the irradiation permission signal (a third signal in the invention) is output (maximum number of images captured) or the output time for which the output of the irradiation permission signal is repeated set in the additional apparatus6until the additional apparatus6outputs the irradiation permission signal.

The console4may include a display43and the number of outputs or the output time set in the additional apparatus6may be displayed on the display43.

In addition, when an imaging start signal (a second signal according to the invention which will be described in detail below) input to the additional apparatus6is turned on, the console4may display information indicating that irradiation is possible on the display43.

Further, while the additional apparatus6is being output the irradiation permission signal, the console4may display information indicating that radiation is being emitted on the display43.

The additional apparatus6is a radiation generation control device according to the invention and includes an additional controller61having a first acquirer62, a second acquirer63, a first connector64, and a second connector65.

The additional controller61includes, for example, a CPU and a RAM and is configured to control the overall operation of each component of the additional apparatus6.

In this case, the additional controller61reads various processing programs stored in a storage (not illustrated), expands the programs in the RAM, and performs various processes according to the processing programs.

The first acquirer62forms a contact (for example, a connector) with the radiation controller11and acquires the irradiation preparation signal output from an irradiation instruction switch5through the radiation controller11(radiation generation apparatus) in this embodiment.

The second acquirer63forms a contact (for example, a connector) with the radiation controller11and acquires the irradiation instruction signal output from the irradiation instruction switch5through the radiation controller11(radiation generation apparatus) in this embodiment.

Since the irradiation instruction signal corresponds to the first signal according to the invention as described above, the second acquirer63forms an acquirer according to the invention.

The first connector64forms a contact (for example, a connector) with the imaging apparatus3and is configured to input the irradiation start signal.

The irradiation start signal is turned on when the imaging apparatus3is in a state in which it can capture images and is turned off when the imaging apparatus3is in a state in which it is not capable of capturing images. Therefore, the irradiation start signal is a signal indicating the driving state of the imaging apparatus3in the invention.

The second connector65is a connector in this embodiment and is connected to the radiation controller11(radiation generation apparatus) by inserting the other end of a cable whose one end is connected to radiation controller11(radiation generation apparatus) into the second connector65.

Therefore, the irradiation permission signal can be output to the radiation controller11.

FIG. 2illustrates the configuration in which the first acquirer62, the second acquirer63, the first connector64, and the second connector65directly transmit and receive information or signals to and from other apparatuses (the first and second acquirers63and the second connector65directly transmit and receive information or signals to and from the radiation control device1and the first connector64directly transmits and receives information or signals to and from the imaging apparatus3). However, at least one of the first acquirer62, the second acquirer63, the first connector64, and the second connector65may be connected to other apparatuses through a relay (not illustrated) that can relay signals.

Further,FIG. 2illustrates a case where the first acquirer62, the second acquirer63, the first connector64, and the second connector65are separately provided. However, at least two of the first acquirer62, the second acquirer63, the first connector64, and the second connector65may be integrated (the components62to65may be shared).

The additional controller61of the additional apparatus6having the above-mentioned configuration can repeatedly output a pulsed irradiation permission signal for instructing the emission of radiation with a predetermined period from the second connector65to the radiation controller11, on the basis of the irradiation instruction signal acquired from the radiation controller11through the second acquirer63and the irradiation start signal input from the imaging apparatus3through the first connector64.

The additional controller61may not output the irradiation permission signal until a predetermined standby time elapses from the detection of the turn-on of the irradiation start signal even if the turn-on of the imaging start signal has been turned on.

The additional controller61outputs a timing signal (a fourth signal in the invention) indicating the imaging timing of a radiographic image from the first connector64to the imaging apparatus3on the basis of the output timing of the irradiation permission signal.

The imaging timing is, for example, the timing when an operation of accumulating charge of a radiographic image starts. That is, the imaging apparatus3according to this embodiment performs an operation which starts to accumulate charge according to the timing signal, sequentially ends the accumulation using a timer of the imaging apparatus3, reads out the charge of each pixel, changes the charge of each pixel to an image, and stores or transmits the image.

This control enables the additional controller61to control both the radiation emission timing based on the irradiation permission signal and the accumulation timing when charge is accumulated in the emission of radiation based on the timing signal. As a result, it is possible to reliably accumulate charge obtained by the emission of radiation and to reliably acquire an image obtained by the emission of radiation.

In a case where the time when the charge accumulation operation starts is set as the imaging timing as described above, the imaging apparatus3may stand by in a state in which it can shift to the accumulation timing corresponding to the imaging operation by the emission of radiation and may start the accumulation operation according to the timing signal.

This control enables the additional controller61to reliably acquire the image obtained by the emission of radiation as in the above-mentioned case.

The imaging timing triggered by the input of the timing signal may be the timing when any one of various operations repeatedly performed by the imaging device3starts in addition to the charge accumulation operation.

For example, in a case where it is necessary to reset the charge accumulated in each pixel before the accumulation operation, the timing when the reset starts may be the imaging timing.

In this case, the imaging apparatus3may be sequentially shifted to the accumulation operation after the reset is completed.

This control enables the imaging apparatus to shift to the accumulation operation that accumulates charge obtained by the emission of radiation in a state in which dark charge, which is a noise component accumulated in each pixel over time before charge is accumulated by the emission of radiation, is output by the reset operation. Therefore, it is possible to acquire an image with less noise.

Alternatively, the timing when the accumulate operation is ended may be the imaging timing. Alternatively, the timing when the reading of the charge accumulated by the timing signal starts may be the imaging timing.

This control enables the additional controller61to control both the radiation emission timing based on the irradiation permission signal and the timing when the accumulation of charge by the emission of radiation based on the timing signal ends or the timing when the charge accumulated by the emission of radiation is read. As a result, it is possible to reliably accumulate the charge obtained by the emission of radiation and to reliably acquire the images obtained by the emission of radiation.

The timing signal may not be used for the start of each operation, but may be used for the end of each operation. For example, the accumulation operation may start at the timing when the timing signal changes from an off state an on state and may end at the timing when the timing signal changes from the on state to the off state.

This control enables the additional controller61to reliably acquire the images obtained by the emission of radiation as in each of the above-mentioned cases.

In this embodiment, the timing signal is repeatedly output with the same period as the irradiation permission signal.

In this embodiment, the additional controller61repeatedly outputs the irradiation permission signal until the number of outputs reaches a predetermined value or until a predetermined output time elapses from the first output.

The timing signal may be output with a predetermined time delay after the irradiation permission signal is output or may be output before the irradiation permission signal is output.

The additional controller61may be configured to include a time for controlling the timing in order to repeatedly transmit the timing signal or the irradiation permission signal with a predetermined period.

Further, the additional controller61may be configured to have a counter that counts the number of outputs in order to repeatedly output the timing signal or the irradiation permission signal until the number of times the timing signal or the irradiation permission signal is output reaches a predetermined value. Alternatively, the additional controller61may be configured to have a timer in order to repeatedly output the timing signal or the irradiation permission signal until a predetermined output time elapses from the first output of the timing signal or the irradiation permission signal.

The timing signal may be output in a stage before the irradiation instruction switch5is pressed to the second stage (the irradiation instruction signal is acquired).

Specifically, for example, the timing signal may be output until the irradiation instruction signal is acquired after a sequence start signal (a fifth signal in the invention) is acquired (the turn-on of the sequence start signal is detected) or until the irradiation preparation signal (a sixth signal in the invention) is acquired (the turn-on of the irradiation preparation signal is detected).

In some cases, a plurality of generation apparatuses are connected in the system100. In this case, one of the generation apparatuses is selected and used.

Similarly, in some cases, a plurality of imaging apparatuses3are connected in the system100. In this case, one of the imaging apparatuses3is selected and used.

FIG. 4illustrates an example of the system100including a plurality of generation apparatuses and a plurality of imaging apparatuses3. In the example of the system100illustrated inFIG. 4, one decubitus imaging table8A and an upright imaging table8B are installed in an imaging room (not illustrated) and a generation apparatus (A) and a generation apparatus (B) are installed so as to mainly correspond to imaging with these tables.

An imaging apparatus (A) is mainly installed in the decubitus imaging table8A and an imaging apparatus (B) is mainly installed in the upright imaging table8B. Each of the decubitus imaging table8A and the upright imaging table8B is configured to accommodate the imaging apparatus3such that the imaging apparatus3can be changed.

An imaging apparatus (C) for capturing an image of a part, such as a hand or a foot, without using an imaging table is installed in the imaging room, separately from the imaging apparatuses (A) and (B). In a case where the imaging apparatus (C) is used, for example, imaging may be performed using the generation apparatus (A) placed on the decubitus imaging table8A or may be performed while changing the irradiation direction of the generation apparatus (B).

In addition, the console4and a plurality of apparatuses (the radiation control devices1and1A and the additional apparatuses6and6A) may be connected to each other through a communication device9illustrated inFIG. 4or the communication network N.

In this configuration, for example, in the capture of still images, particularly, in a case where there are no restrictions on the size of the image that can be captured, it is possible to minimize the replacement of the imaging apparatus3or the movement the radiation generator2and thus to effectively perform imaging.

However, for example, in a case where the size or resolution of the image that can be captured by each imaging apparatus3are not matched with an imaging method to be performed, imaging is performed while changing the imaging apparatuses (A), (B), and (C).

Operation

The operation of the system100will be described.FIGS. 5 and 6are ladder charts illustrating the operation of the system100according to this embodiment andFIG. 7is a timing chart illustrating the operation of the system100.

A: When Apparatus is Installed, when Apparatus Starts Up, when Connected Apparatus is Changed, and when Connected Apparatus is Periodically Checked

First, the console4, particularly, the imaging apparatus control console42checks the imaging apparatus3or the additional apparatus6connected to an imaging environment controlled by the console4when an apparatus is installed, an imaging system starts up, when the connected apparatus is changed, and when the connected apparatus is periodically checked as illustrated inFIG. 5(Step S1) and displays an apparatus configuration and a connection configuration on the display43of the console4(Step S2).

The imaging apparatus3and the additional apparatus6connected to the imaging environment controlled by the console4can be checked by, for example, a method in which the console4requests the imaging apparatus3and the additional apparatus6to transmit information indicating whether the apparatuses are connected and IDs and the imaging apparatus3and the additional apparatus6return the information indicating whether the apparatuses are connected and IDs.

For example, the unique ID of each apparatus, such as a MAC address uniquely set to an apparatus, the unique BSSID of an apparatus, or a serial number uniquely set to an apparatus, may be used as the ID. In addition, an ID that is set later, such as a set IP address or a set ESSID, may be used.

B: Preparation for Imaging

Then, if the console4receives an imaging order from the host system7such as RIS or HIS (Step S3), the console4displays the received imaging order on a screen of the console4(Step S4).

At that time, the reception of a new imaging order may be notified to an operator using light or sound.

The radiographer performs, for example, an operation of changing an imaging sequence from the displayed imaging order and selects an imaging order for the next imaging (Step S5).

At that time, an imaging apparatus3to be used may be selected from a plurality of connected imaging apparatuses3.

In addition, a recommended imaging apparatus3may be automatically selected from the plurality of connected imaging apparatuses3according to the imaging technique of the radiographer.

In a case where there is no particular change in the imaging order, the imaging apparatus3used in the previous imaging operation may be continuously selected.

If the imaging apparatus3to be used is selected, the console4transmits a connection request to the imaging apparatus3and the additional apparatus6(Step S6).

If the imaging apparatus3or the additional apparatus6receives the connection request, it is connected to the console4(Step S7).

As illustrated inFIG. 5, the connection request may be transmitted from the console4to the additional apparatus6and may be further transmitted from the additional apparatus6to the imaging apparatus3.

As illustrated inFIG. 2, the imaging apparatus3and the console4can be connected to each other through the communication network N or can be directly connected to each other. In a case where the console4and the imaging apparatus3are directly connected to each other, the console4is connected to the imaging apparatus3that is not connected to the additional apparatus6and there is a possibility that a connection configuration will not be established in a state in which the additional apparatus6and the imaging apparatus3cooperate with each other.

However, this connection between the imaging apparatus3and the console4through the additional apparatus6makes it possible for the console4to be reliably connected to the imaging apparatus3connected to the additional apparatus6.

Alternatively, the console4may transmit a connection request to each imaging apparatus3and then each imaging apparatus3may transmit a connection request to the additional apparatus6, which is not illustrated.

Since the console4sets the imaging apparatus3to be used for imaging, this configuration makes it possible to reliably select the imaging apparatus3to be used, to connect the imaging apparatus3and the additional apparatus6, and to establish a state in which the additional apparatus6and the imaging apparatus3that is used cooperate with each other, without selecting a wrong imaging apparatus3.

In addition, this configuration makes it possible to select an imaging apparatus3not only from the imaging apparatus3connected to the additional apparatus6as described above but also from all of the usable imaging apparatuses3.

In a case where the imaging apparatus3starts connection, the imaging apparatus3may automatically change its state from the above-mentioned mode in which preparation for imaging or imaging is possible and power consumption is low to a mode in which power consumption is higher than that in the low-power-consumption mode.

Then, if the radiographer sets, for example, imaging conditions with the console4and instructs the console4to start imaging, the console4turns on the sequence start signal that instructs the imaging apparatus3and the additional apparatus6to start an imaging sequence. Then, the console4transmits the sequence start signal to the imaging apparatus3and the additional apparatus6(Step S8). The sequence start signal can be transmitted using, for example, the information signal which is transmitted and received between the console4and the additional apparatus6and the information signal which is transmitted and received between the additional apparatus6and the imaging apparatus3.

If the imaging apparatus3and the additional apparatus6detect that the sequence start signal has been turned on, they start preparation for imaging.

In a case where the additional apparatus6is configured to transmit the timing signal in a stage before the irradiation instruction switch5is pressed, the additional apparatus6may perform control such that a reading instruction signal (seeFIG. 22) is turned on and the timing signal is repeatedly transmitted to the imaging apparatus3at predetermined intervals after it is detected that the sequence start signal has been turned on (Step S9).

The imaging apparatus3repeats a reading operation whenever the timing signal is received. Then, the temperature of the circuit in the imaging apparatus3rises. That is, the reading operation which is repeatedly performed by the imaging apparatus3in this stage is the warm-up of the imaging apparatus3.

In an initial stage in which the imaging apparatus3repeats the reading operation, the imaging apparatus3notifies the console4that a warm-up has started (Step S10).

The imaging apparatus3needs to perform a reading operation (reset operation) for removing the charge accumulated immediately before imaging.

Since the imaging apparatus3consumes power in the reading operation, the temperature of the imaging apparatus3rises with an increase in the power consumption. The sensitivity of a light receiver of the imaging device3is particularly changed by the temperature rise and image density based on the incident amount of radiation also changes. The change in image density due to the temperature rise is not a problem in a case where one still image is captured. However, in a case where dynamic imaging (for repeatedly capturing still images) is performed as in the system100according to this embodiment, the change in image density due to the temperature rise during imaging becomes a problem.

However, the above-mentioned configuration in which the imaging apparatus performs a warm-up makes it possible to reduce the change in image density due to the temperature rise.

The imaging apparatus3may acquire a correction image at any timing when Step S9is repeated a plurality of times.

For example, in a case where the imaging apparatus3is configured to perform a warm-up (to perform the reading operation before the irradiation instruction switch5is pressed), the imaging apparatus3may transmit an image which has been read in the second half of the warm-up as the correction image to the console4(Step S11).

A plurality of pixels of the imaging apparatus3have different characteristics and the charge levels corresponding to the brightness of the image are different in the pixels even when radiation is not emitted. Therefore, the image read in the second half of the warm-up is acquired as the correction image and, for example, each signal value of the correction image is subtracted from each signal value of a captured image which is obtained later to obtain a captured image in which a variation for each pixel has been removed.

In this embodiment, a case where the correction image is simply subtracted from the captured image has been described as an example of the method of using the correction image. However, noise components may be removed using various operations.

In a case where the read operation (reset operation) for removing the charge accumulated immediately before imaging other than the acquisition of the correction image is performed, at least one of the following processes may be performed as the same operation as that in normal imaging:

a process of converting the removed charge into an image;

a process of storing the image data of the obtained image in the storage of the imaging apparatus3; and

a process of transmitting the imaged data or the image data stored in the storage of the imaging apparatus3to the console4.

The above-mentioned process which is the same as that in normal imaging is performed under the conditions close to those of actual imaging Therefore, according to this configuration, a difference in imaging in the subsequent steps is small and it is possible to reduce, for example, the influence of the temperature rise.

In contrast, in a case where the above-mentioned process which is the same as that in normal imaging is performed, the following problems arise:

the amount of power consumption increases;

since an unnecessary image obtained while no radiation is emitted is stored in the storage of the imaging apparatus3, the capacity of the storage that can be used at the time of imaging is reduced;

since the unnecessary image obtained while no radiation is emitted is transmitted to the console, the transmission of the unnecessary image occupies a part of communication capacity; and

since the unnecessary image is stored in the storage of the console, the capacity of the storage that can be used at the time of imaging is reduced.

Therefore, some of the processes may be omitted in order to avoid the problems.

The imaging apparatus3can be configured to complete the warm-up in a case where the number of reading operations as the warm-up reaches a predetermined value or the reading operation period has elapsed. For example, in Step S25(seeFIG. 6) in which the irradiation start signal is turned on, which will be described below, control is performed such that the irradiation start signal is not turned on until the number of reading operations reaches a predetermined value or the reading operation period elapses, which makes it possible not to start imaging using the emission of radiation until the warm-up is completed.

Then, the imaging apparatus3notifies the console4that preparation for imaging has been completed (Step S12).

At that time, “Imaging is available” may be displayed on the display43of the console4(Step S13).

C: Imaging Check

The additional apparatus6continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation of the imaging apparatus3whenever the timing signal is received.

If the radiographer ends the positioning of the subject and presses the irradiation instruction switch5to the first stage (Step S14), the irradiation instruction switch5turns on the irradiation preparation signal output to the radiation controller11through the console4(Step S15).

If the radiation controller11of the radiation generation apparatus detects that the irradiation preparation signal has been turned on, it turns on the irradiation preparation signal output to the high voltage generator12and the additional apparatus6(Step S16). Then, the first acquirer62of the additional apparatus6acquires the irradiation preparation signal (which is output before the irradiation instruction signal and after the sequence start signal is turned on).

As such, the radiation generation apparatus including the radiation controller11starts preparation for the emission of radiation in response to the irradiation preparation signal.

If the additional controller61of the additional apparatus6detects that the irradiation preparation signal from the radiation controller11has been turned on, it transmits the imaging preparation signal to the console4(Step S17).

If the console4receives the imaging preparation signal, it starts preparation for imaging. The preparation for imaging in the console4is, for example, an operation of checking whether the settings of the imaging apparatus control console42and the settings of the radiation control console41that controls the emission of radiation in the console4are the same or an operation of checking whether the designated imaging conditions are set in the imaging apparatus3.

If preparation for imaging is completed, the console4turns on an imaging preparation completion signal output to the additional apparatus6(Step S18).

At that time, “Imaging is being performed” may be displayed on the display43of the console4(Step S19).

In the stage in which the preparation for imaging has been completed, for example, the input of an instruction to change the imaging conditions to the console4may be locked such that the imaging conditions are not changed.

In a case where a still image is captured, imaging ends in a short time. Therefore, the risk of changing the conditions during imaging is low and there is little need for this configuration. However, in the case of dynamic imaging, since the imaging period is long, there is a high risk that the radiographer or a third party other than the radiographer will intentionally or unintentionally operate a console screen to change the imaging conditions.

For this reason, in the process from this stage to the end of the sequence after Step S45which will be described below, the input of, for example, an instruction to change the imaging conditions to the console4is locked, which makes it possible to reliably prevent the change in the imaging conditions.

FIG. 5illustrates a case where the imaging preparation signal is output from the additional apparatus6to the console4. However, in some cases, the imaging preparation signal is not output to the console4, but is output to the imaging apparatus3such that the imaging apparatus3prepares imaging and the imaging preparation completion signal is output from the imaging apparatus3to the additional apparatus6after the imaging apparatus3completes preparation for imaging.

Further, in some cases, the imaging preparation signal is input to both the console4and the imaging apparatus3such that both the console4and the imaging apparatus3prepare imaging and the imaging preparation completion signal is output from the console4and the imaging apparatus3to the additional apparatus6after both the console4and the imaging apparatus3complete preparation for imaging. Then, it is determined that the entire preparation for imaging has been completed in a stage in which the additional apparatus6has received the imaging preparation completion signal from both the console4and the imaging apparatus3.

In a case where the radiation controller11of the radiation generation apparatus has a connector that can input the imaging preparation completion signal indicating that preparation for imaging in the external device has been completed, the additional apparatus6may output the imaging preparation completion signal to the radiation controller11, which is not illustrated.

The radiation controller11detects that the imaging preparation completion signal from the additional apparatus6has been turned on to detect that the imaging apparatus3is in a state in which it can perform imaging Since the radiation control device1performs control such that radiation is emitted after it is detected that the imaging preparation completion signal has been turned on, it is possible to surely eliminate the risk that the imaging apparatus3will emit radiation while imaging is not possible and the subject will be unnecessarily exposed to radiation.

D: Execution of Imaging

Then, if the radiographer presses the irradiation instruction switch5to the second stage (Step S20), the irradiation instruction switch5turns on the irradiation instruction signal transmitted to the radiation controller11through the console4(Step S21).

In this case, the additional apparatus6continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

Even if the irradiation instruction signal is input from the irradiation instruction switch5, the radiation controller11of the radiation generation apparatus does not transmit the irradiation signal to the high voltage generator12since the irradiation permission signal from the additional apparatus6is in an off state at this time.

The radiation controller11turns on the irradiation instruction signal transmitted to the additional controller61(Step S22).

In a case where the additional apparatus6receives the irradiation instruction signal, the additional apparatus6turns on the imaging start signal which notifies whether to permit the start of imaging and is output to the imaging apparatus3and the console4(Steps S23and S24).

In a case where it is detected that the imaging start signal has been turned on, for example, the imaging apparatus3turns on the irradiation start signal output to the additional apparatus6, using the end of its reading operation performed at that time as a trigger, as illustrated inFIG. 6(Step S25). The reason is as follows. The reading operation of the imaging apparatus3sequentially reads the charge accumulated in the pixels which are two-dimensionally arranged to acquire the image of the entire light receiving surface. In a case where the irradiation start signal is turned on to emit radiation during the reading operation, there is a difference between the signal value of the pixel from which the reading of charge has been completed and the signal value of the pixel from which the reading of charge has not been completed. As a result, image quality is significantly degraded.

In contrast, in this embodiment, the emission of radiation and the image reading operation of the imaging apparatus3are performed on the basis of the irradiation permission signal and the timing signal from the additional apparatus6, which will be described below. Therefore, the emission of radiation during the reading operation does not occur in a normal routine. Thus, the irradiation start signal may be turned on, without considering the reading timing of the imaging apparatus3.

The imaging apparatus3repeats the image reading operation even after the irradiation start signal is turned on. The image read after the irradiation start signal is turned on is stored as the captured image in the memory of the imaging apparatus3or is transmitted to the console4.

If the additional apparatus6detects that the irradiation start signal from the imaging apparatus3has been turned on, it detects that the imaging apparatus3is in a state in which the imaging apparatus3can perform imaging and repeatedly transmits the irradiation permission signal to the radiation controller11whenever the timing signal is transmitted to the imaging apparatus3(Step S26).

The radiation controller11of the radiation generation apparatus repeatedly transmits the irradiation signal to the high voltage generator12since the imaging instruction signal and the irradiation permission signal are aligned whenever the irradiation permission signal is received.

Whenever the irradiation signal is received, the high voltage generator12repeatedly generates a high voltage required for emitting radiation and repeatedly outputs the high voltage as an irradiation output to the radiation generator2.

The radiation generator2repeatedly emits radiation to the imaging apparatus3whenever the irradiation output is input (Step S27).

The emitted radiation is transmitted through the subject (not illustrated) disposed between the imaging apparatus3and the radiation generator2and is then incident on the imaging apparatus3.

Whenever the timing signal is received, the imaging apparatus3repeats a process of accumulating the amount of charge corresponding to the intensity of the incident radiation (Step S28) and reading the charge as a captured image (Step S29).

The imaging apparatus3transmits the read radiographic image to the console4(Step S30).

In a case where the captured image is configured to be transmitted to the console4and is not transmitted to the console4in time due to the amount of data or a communication environment, some of a plurality of captured images or a part of one captured image may be stored in the imaging apparatus3and the rest may be transmitted to the console4.

An example of the operation of the imaging apparatus3will be further described. Here, a case where the accumulation of charge starts in response to the timing signal will be described.

Reset Operation/Correction Image Acquisition Operation

In the reset operation performed before imaging, the imaging apparatus3can repeat the above-mentioned operation while there is no radiation emitted from the radiation generation apparatus to output the charge (a dark charge or a dark current) which has been accumulated in each pixel and is not based on the emission of radiation, thereby resetting the charge which has been accumulated in each pixel, is not based on the emission of radiation, and is a noise component with respect to the image obtained by the charge based on the emission of radiation. Further, in the reset operation, control may be performed which the reader34does not convert the input charge into image data (operation before t1).

In a correction image acquisition operation performed before or after imaging, the imaging device3can repeat the above-mentioned operation while there is no radiation emitted from the radiation generation apparatus to output the charge (a dark charge or a dark current) which has been accumulated in each pixel and is not based on the emission of radiation, thereby resetting the charge which has been accumulated in each pixel, is not based on the emission of radiation, and is a noise component with respect to the image obtained by the charge based on the emission of radiation. In the correction image acquisition operation, the reader34converts the input charge into image data and the image data is stored. Therefore, it is possible to store a noise component while radiation is not emitted and to remove the noise component by subtracting the noise component from the image data obtained while radiation is emitted. The correction image acquisition operation may be performed as a part of the reset operation (operation before t1).

Operation of Ending Reset Operation/Correction Image Acquisition Operation

If the irradiation instruction signal in Step S21is turned on following the reset operation or the correction image acquisition operation, the imaging start signal input to the imaging apparatus3is turned on (Step S23). Then, the imaging apparatus3stops the reset operation or the correction image acquisition operation.

In a case where the correction image acquisition operation has not completed the acquisition of a predetermined number of correction images even though the imaging start signal has been turned on, the correction image acquisition operation is not stopped and is continuously performed until a predetermined number of correction images are acquired. Then, the correction image acquisition operation is stopped.

If the reset operation or the correction image acquisition operation is stopped, the imaging apparatus3stops the reset operation or the correction image acquisition operation and turns on the irradiation start signal in Step S25to notify that the imaging apparatus3is in a state in which it can perform imaging (t1).

Operation

In a case where the imaging apparatus3receives the timing signal from the additional controller61, it applies the off-voltage to each scanning line32band changes to a state in which the charge generated by the radiation detection element32dcan be accumulated in the pixel, as illustrated inFIG. 7(t2, t6, t10, . . . ).

The additional controller61outputs the irradiation permission signal at the timing that is operatively associated with the timing when the timing signal is transmitted. The radiation generation apparatus irradiates the imaging apparatus3with radiation in response to the irradiation permission signal (Step S27; t3, t7, t11, . . . ).

The imaging apparatus3continues the mode for accumulating charge for a predetermined period of time, using a timer provided in the imaging apparatus3(t2to t4, t6to t8, t10to t12, . . . ).

In a case where the imaging apparatus3receives radiation in the mode for accumulating charge, each radiation detection element32dof the radiation detector32generates charge and the charge is accommodated in each pixel (Step S28).

Then, the imaging apparatus3performs the reading operation which applies the on-voltage to each switching element32eafter the predetermined period of time elapses using the timer provided in the imaging apparatus3to output the charge accumulated in each pixel to the signal line32c. In the reading operation of the imaging apparatus3, the reader34reads the input charge and converts the charge into image data. In addition, the imaging apparatus3transmits at least a part of the image data to the console4(Steps S29and S30; t4to t5, t8to t9, t12to t13, . . . ).

Another Embodiment of Operation Control Method

The example in which the imaging apparatus changes to a state in which it can accumulate charge in the pixels in response to the timing signal from the additional controller61has been described above. However, control may be performed such that the imaging apparatus performs other operations in response to the timing signal.

For example, another control method may perform control such that, after the imaging apparatus3ends the reading operation (t4to5, t8to t9, t12to t13, . . . ) of discharging the charge accumulated in each pixel to the signal line32c, the imaging apparatus3changes to the state (t6to t8, t10to t12, . . . ) in which it can accumulate charge in the pixels, without waiting for the timing signal from the additional controller61.

Then, the additional controller61performs control such that the timing signal is output at the timing which is operatively associated with the timing when the radiation generation apparatus transmits the irradiation permission signal for radiation emission control.

The imaging apparatus3changes to the reading operation that outputs the charge accumulated in each pixel to the signal line32cin response to the received timing signal (t4, t8, t12, . . . ).

The repetition of the above-mentioned operation control makes it possible to perform imaging while matching the radiation emission timing of the radiation generation apparatus and the image generation timing of the imaging apparatus.

E: End of Imaging

The additional apparatus6counts the number of times the irradiation permission signal is transmitted from the time when the emission of radiation starts and determines whether the number of captured images reaches a predetermined maximum value whenever the number of times the irradiation permission signal is transmitted is counted. In a case where it is determined that the counted number of times the irradiation permission signal is transmitted (the number of captured images) reaches the maximum number of captured images, the additional apparatus6turns off the imaging start signal (Step S31) and stops the output of the timing signal or/and the irradiation permission signal.

Control may be performed such that the imaging apparatus3performs the operation of accumulating the amount of charge corresponding to the intensity of the incident radiation (Step S28) and reading the charge as a captured image (Step S29) at least once after the additional apparatus6outputs the irradiation permission signal last. In this case, it is possible to reliably read the image obtained by the last emission of radiation, to use the read image as the captured image, and to reliably prevent the subject from being unnecessarily exposed to radiation.

In addition, control may be performed such that the imaging apparatus3further performs the operation of accumulating charge and reading the charge as a captured image after the additional apparatus6outputs the irradiation permission signal last, and then the imaging apparatus3performs the operation of accumulating charge (Step S28) and reading the charge as a captured image (Step S29). Since the captured image is an image captured while no radiation is emitted, these images can be used to correct the images captured while radiation is emitted, similarly to the correction image.

In other words, for the 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, the correction images captured before and after imaging using radiation may be used. In this case, the correction images captured before and after imaging using radiation may be used to predict a change in the correction image during imaging and the correction image may be generated on the basis of the prediction result. The correction image can be generated, for example, by averaging the correction images captured before and after radiography or by performing linear or curve compensation for fluctuations.

In a case where a still image is captured, since the time required for imaging is short, a change in the correction image before and after imaging is small. However, in the case of dynamic imaging, the time required for imaging is longer than that in a case where a still image is captured. Therefore, in a case where the correction images before and after imaging are used as described above, it is possible to perform correction, also considering fluctuations during imaging.

The number of captured images may not be counted on the basis of the number of times the irradiation permission signal is transmitted as described above, but may be counted on the basis of the number of times the timing signal is output after the start of imaging.

In addition, the number of captured images may not be counted on the basis of the number of times the irradiation permission signal is transmitted as described above, but may be counted on the basis of the time elapsed since the start of imaging.

If it is detected that the imaging start signal has been turned off and imaging after radiation is emitted or imaging for acquiring the correction image ends, the imaging apparatus3turns off the reading instruction signal (seeFIG. 22) and transmits the images remaining in the memory of the imaging apparatus3(the captured images which have not been transmitted) to the console4(Step S32). Then, if the transmission of the remaining images is completed, the imaging apparatus3transmits a remaining image transmission completion signal to the console4(Step S33).

If the console4detects that the imaging start signal has been turned off, it starts an operation of checking the transmitted captured image.

If the console4receives the remaining image transmission completion signal, it transmits an image deletion signal for instructing the deletion of an image to the imaging apparatus3(Step S34).

Control may be performed such that the image deletion signal is transmitted after the captured image check operation is completed and it is checked that there is no problem in all of the transmitted images.

At that time, “End of imaging” may be displayed on the display43of the console4(Step S35).

In a case where the imaging apparatus3receives the image deletion signal, it deletes the captured images stored in the memory (Step S36). Therefore, the free space of the memory can be ensured for the next imaging.

If the radiographer who has checked the end of imaging (for example, who has seen “the end of imaging” displayed on the console4) releases the second stage of the irradiation instruction switch5(Step S37), the irradiation instruction switch5turns off the irradiation instruction signal (Step S38) and the radiation controller11also turns off the irradiation instruction signal (Step S39).

Then, if the radiographer opens the first stage of the irradiation instruction switch5(Step S40), the irradiation instruction switch5turns off the irradiation preparation signal (Step S41) and the radiation controller11also turns off the irradiation preparation signal (Step S42).

If the additional apparatus6detects that the irradiation preparation signal has been turned off, it notifies the console4that the irradiation preparation signal has been turned off.

If the console4receives the notification from the additional apparatus6, it turns off the imaging preparation completion signal and changes a sequence state to an irradiation preparation state.

If the additional apparatus6detects 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 apparatus3and the console4(Steps S43and S44).

If the imaging apparatus3receives the imaging end signal, it transmits a standby signal to the console4(Step S45).

If the console4receives the standby signal, it monitors the presence and absence of re-imaging or another imaging for a predetermined period. In a case where there is no re-imaging or another imaging for a predetermined period, the console4turns off the sequence start signal to change the sequence state to a standby state in which it waits for an imaging instruction.

In this way, a series of imaging operations ends.

The system100according to this embodiment operates as described above and dynamic imaging that repeatedly captures a plurality of still images in a short time is performed.

Effect

As described above, the system100according to the first embodiment is configured by connecting the additional controller61to the radiation control device1that can perform the emission of radiation only once in response to one radiation emission instruction in the conventional system100A illustrated inFIG. 1. In the system100, the radiation control device1can output the irradiation signal a plurality of times in response to one irradiation instruction signal acquisition operation (the detection of the turn-on of the irradiation instruction signal). Therefore, it is possible to perform imaging that repeatedly captures still images a plurality of times in a short time, that is, dynamic imaging using the imaging apparatus3.

The conventional system100A illustrated inFIG. 1is widely used as a radiography apparatus that captures a simple still image. Therefore, a medical institution using the conventional system100A can easily modify the conventional system100A including the existing radiation generation apparatus so as to respond to the dynamic imaging only by adding the imaging apparatus3and the additional apparatus6, without updating the expensive radiation generation apparatus.

Second Embodiment

A second embodiment of the invention will be described with reference toFIGS. 2 to 5 and 8 to 14. The same configurations as those in Conventional Technology 1 and the first embodiment are denoted by the same reference numerals and the description thereof will not be repeated. In addition, various modification patterns described in the first embodiment may also be applied to this embodiment.

System Configuration

First, a system configuration of a radiography system (hereinafter, referred to as a system100) according to this embodiment will be described.FIG. 2is a block diagram illustrating the system100andFIG. 3is a block diagram illustrating a radiography apparatus3.

For example, similarly to the system100according to the first embodiment, the system100according to this embodiment differs from the conventional system100A in that the radiography apparatus (hereinafter, referred to as the imaging apparatus3) replaces the cassette3A and the imaging apparatus control console42and the additional apparatus6are added, as illustrated inFIG. 2.

Operation

The operation of the system100will be described.FIGS. 5, 12, and 13are ladder charts illustrating the operation of the system100according to this embodiment.FIG. 8is a table illustrating the correspondence between generation apparatuses and the imaging apparatuses3that can be connected to the system100and the frame rates corresponding to these apparatuses.FIGS. 9 to 11illustrate examples of the display screen of the display43of the console4.FIG. 14is a timing chart illustrating the operation of the system100.

A: When Apparatus is Installed, when Apparatus Starts Up, when Connected Apparatus is Changed, and when Connected Apparatus is Periodically Checked

First, the console4, particularly, the imaging apparatus control console42checks the imaging apparatus3or the additional apparatus6connected to an imaging environment controlled by the console4when an apparatus is installed, an imaging system starts up, when the connected apparatus is changed, and when the connected apparatus is periodically checked as illustrated inFIG. 5(Step S1) and displays an apparatus configuration and a connection configuration on the display43of the console4(Step S2).

The imaging apparatus3and the additional apparatus6connected to the imaging environment controlled by the console4can be checked by, for example, a method in which the console4requests the imaging apparatus3and the additional apparatus6to transmit information indicating whether the apparatuses are connected and IDs and the imaging apparatus3and the additional apparatus6return the information indicating whether the apparatuses are connected and IDs.

For example, the unique ID of each apparatus, such as a MAC address uniquely set to an apparatus, the unique BSSID of an apparatus, or a serial number uniquely set to an apparatus, may be used as the ID. In addition, an ID that is set later, such as a set IP address or a set ESSID, may be used.

B: Preparation for Imaging

Then, if the console4receives an imaging order from the host system7such as RIS or HIS (Step S3), it displays the received imaging order on the screen of the console4(Step S4).

At that time, the reception of a new imaging order may be notified to the operator using light or sound.

The radiographer performs, for example, an operation of changing an imaging sequence from the displayed imaging order and selects an imaging order for the next imaging (Step S5).

Unlike a fluoroscopic apparatus in which a combination of a radiation generating apparatus and a radiography apparatus is fixed, the system100according to this embodiment can perform imaging even in a case where a combination of the generation apparatus and the imaging apparatus3is changed. Therefore, it is possible to select an imaging apparatus suitable for the imaging order and the imaging technique from a plurality of cassette-type imaging apparatuses3having different sizes and performances and then perform imaging.

In this case, for example, an imaging apparatus3(for example, an imaging apparatus (A) or (C)) suitable for the current imaging is selected from a plurality of imaging apparatuses3that can be connected to the console4and can be used for imaging as illustrated inFIG. 8and imaging is performed.

In the case of a system100in which a plurality of generation apparatuses are connected to one console4, a generation apparatus (for example, a generation apparatus (A) or (B)) used for imaging is selected and imaging is performed.

If at least one of the generation apparatus and the imaging apparatus3is selected, the additional controller61of the additional apparatus6or the console4according to this embodiment can acquire an irradiation frame rate or an imaging frame rate.

The irradiation frame rate or the imaging frame rate to be acquired may be input (selected) to the console4by the radiographer or may be received from the generation apparatus or the imaging apparatus3.

In a case where the irradiation frame rate or the imaging frame rate is received from the generation apparatus or the imaging apparatus3, one frame rate selected in each apparatus may be received or all of a plurality of frame rates corresponding to each apparatus may be received.

It is necessary to satisfy all of the following determination conditions (1) to (3) in order to perform imaging without any problem.

(1) The acquired irradiation frame rate is a value corresponding to the generation apparatus.

(2) The acquired imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

Therefore, the additional controller61or the console4determines whether or not all of the determination conditions are satisfied.

Here, the “irradiation frame rate” indicates the number of times radiation is generated by the generation apparatus per unit time and corresponds to the transmission period of the irradiation permission signal by the additional controller61.

The “imaging frame rate” indicates the number of times a radiographic image is generated by the imaging apparatus3per unit time and corresponds to the transmission period of the timing signal by the additional controller61.

In a case where at least one of the number of irradiation frame rates and the number of imaging frame rates is two or more, there are a plurality of combinations of the irradiation frame rates and the imaging frame rates. Therefore, determination may be performed a plurality of times in accordance with the plurality of combinations.

Here, N is an integer equal to or greater than 1. However, for example, in a case where imaging is performed while the emission of radiation is thinned out at predetermined intervals, it is preferable that N is an integer equal to or greater than 2.

In a case where at least one of the number of imaging frame rates received from the imaging apparatus3and the number of irradiation frame rates received from the generation apparatus is two or more, there may be a plurality of combinations of the imaging frame rates and the irradiation frame rates. Therefore, it may be determined in advance whether each combination satisfies all of the above-mentioned determination conditions.

In a case where the generation apparatus or the imaging apparatus is configured to select only the corresponding irradiation frame rate or the corresponding imaging frame rate, the generation apparatus, the imaging apparatus3, or the console4can omit the determination of whether the determination conditions (1) and (2) are satisfied.

If any of the determination conditions is not satisfied as a result of checking whether all of the determination conditions are satisfied, at least one of the following measures (4) to (6) may be taken.

(4) Among the imaging apparatus3used, the generation apparatus used, the imaging frame rate of the imaging apparatus3, and the irradiation frame rate of the generation apparatus, a component that does not satisfy the above-mentioned relationship is not selected or an input value is not received (not set).

(5) A setting candidate that does not satisfy the above-mentioned relationship is grayed out (display to notify the determination result is performed) and is excluded from a selection target such that it is not selectable.

(6) Even if a component can be selected, it does not advance to the next sequence. Alternatively, imaging is not permitted.

The system may notify the photographer of an error to warn the photographer that the relationship is not satisfied when the above-described measures are taken. The warning may be performed by voice or may be performed by display for notifying the determination result using the display43.

That is, the additional controller61or the console4has a function of notifying the determination result in a manner that the photographer can recognize the determination result or a function of outputting the determination result.

In a case where all of the determination conditions (1) to (3) are satisfied, the additional controller61or the console4permits the generation apparatus to emit radiation.

This configuration makes it possible to reliably prevent imaging in a state in which a selection that does not satisfy the above-mentioned relationship is made.

An operation of setting the irradiation frame rate and the imaging frame rate in an imaging room where there are a combination of imaging apparatuses other than the imaging apparatuses (A) and (C) and a combination of the generation apparatuses (A) and (B) illustrated inFIG. 8Awill be described as an example.

First, it is assumed that the radiographer selects the generation apparatus (A) as the generation apparatus to be used, as illustrated inFIG. 9(the generation apparatus (A) is displayed in a selected generation apparatus display field43a). The irradiation frame rates corresponding to the generation apparatus (A) (that can perform irradiation) are, for example, three types of 15 frames/s (Hz), 10 frames/s (Hz), and 5 frames/s (Hz).

FIG. 9illustrates a case where the generation apparatus (A) is selected and only the information of the generation apparatus (A) is displayed in the display field43a. However, the display field43amay be configured such that the information of a plurality of generation apparatuses can be displayed in the form of options and the information of the selected generation apparatus (A) may be displayed differently from the information of other generation apparatuses.

Then, the radiographer selects the imaging apparatus3to be used. Here, the imaging apparatus (A) and the imaging apparatus (C) can be selected since they include values that are N times (N is an integer equal to or greater than 1) the irradiation frame rates (15, 10, and 5) which can correspond to the generation apparatus (A) selected first among the corresponding imaging frame rates.

Therefore, in a case where the imaging apparatus (A) is selected (a corresponding icon43bis displayed by a solid line), the selectable imaging frame rate is 15 Hz (that is three times an irradiation frame rate of 5 Hz) from the relationship with a combination of the irradiation frame rates corresponding to the generation apparatus (A).

Among the selectable imaging frame rates, an imaging frame rate with a relatively large (high) value may be selected as a basic imaging frame rate.

In a technique that changes the irradiation frame rate and then performs imaging, if the imaging frame rate is changed in accordance with a change in the irradiation frame rate, an operation that is complicated and takes a lot of time, such as an operation of restarting the imaging apparatus (A) in association with a change in the setting of the imaging apparatus (A), is required. However, the fixation of the imaging frame rate of the imaging apparatus (A) to the basic imaging frame rate makes it possible to eliminate the switching time.

As such, if 15 Hz is selected as the basic imaging frame rate, 15 Hz or 5 Hz that is 1/N times (where N is an integer equal to or greater than 1) the basic imaging frame rate among the irradiation frame rates, to which the generation apparatus (A) can correspond, can be selected as the irradiation frame rate.

If 10 Hz is selected as the irradiation frame rate, the system may be configured such that 10 Hz is not selectable. At this time, for example, as illustrated inFIG. 10, information indicating that the irradiation frame rate is not selectable (information for notifying the determination result: for example, characters43cof “impossible”) may be displayed in the vicinity of the displayed irradiation frame rate.

As another example, as illustrated inFIG. 11, in a case where the imaging apparatus (C) has been selected (a corresponding icon43dis displayed by a solid line), 10 Hz can be selected as the basic imaging frame rate from the relationship with the corresponding frame rate of the generation apparatus.

In addition, 10 Hz or 5 Hz can be selected as the irradiation frame rate.

It is desirable to set a necessary value to the irradiation frame rate according to an imaging technique. For example, it is desirable to set an irradiation frame rate of at least 2 Hz or more in order to capture the image of the dynamics of a slow change such as breathing.

Therefore, in a case where the set irradiation frame rate is equal to or greater than 2 Hz, the additional controller61or the console4can be configured to permit the generation apparatus to emit radiation.

Alternatively, the minimum necessary frame rate may be stored for each imaging part or imaging technique. In a case where the irradiation frame rate set according to the selected imaging part or imaging technique is higher than the minimum necessary frame rate, the generation apparatus may be permitted to emit radiation.

Among a plurality of connected imaging apparatuses3, a recommended imaging apparatus3may be automatically selected according to the imaging technique of the radiographer.

Further, in a case where there is no particular change, the imaging apparatus3which has been used in the previous imaging may be continuously selected.

If the imaging apparatus3to be used is selected, as illustrated inFIG. 5, the console4transmits a connection request to the imaging apparatus3and the additional apparatus6(Step S6).

If the imaging apparatus3or the additional apparatus6receives the connection request, it is connected to the console4(Step S7).

As illustrated inFIG. 5, the connection request may be transmitted from the console4to the additional apparatus6and may be further transmitted from the additional apparatus6to the imaging apparatus3.

As illustrated inFIG. 2, the imaging apparatus3and the console4can be connected to each other through the communication network N or can be directly connected to each other. In a case where the console4and the imaging apparatus3are directly connected to each other, the console4is connected to the imaging apparatus3that is not connected to the additional apparatus6and there is a possibility that a connection configuration will not be established in a state in which the additional apparatus6and the imaging apparatus3cooperate with each other.

However, this connection between the imaging apparatus3and the console4through the additional apparatus6makes it possible for the console4to be reliably connected to the imaging apparatus3connected to the additional apparatus6.

Alternatively, the console4may transmit a connection request to each imaging apparatus3and then each imaging apparatus3may transmit a connection request to the additional apparatus6, which is not illustrated.

Since the console4sets the imaging apparatus3to be used for imaging, this configuration makes it possible to reliably select the imaging apparatus3to be used, to connect the imaging apparatus3and the additional apparatus6, and to establish a state in which the additional apparatus6and the imaging apparatus3that is used cooperate with each other, without selecting a wrong imaging apparatus3.

In addition, this configuration makes it possible to select an imaging apparatus3not only from the imaging apparatus3connected to the additional apparatus6as described above but also from all of the usable imaging apparatuses3.

When the imaging apparatus3starts connection, the imaging apparatus3may automatically change its state from the above-mentioned mode in which preparation for imaging or imaging is possible and power consumption is low to a mode in which power consumption is higher than that in the low-power-consumption mode.

Then, if the radiographer sets, for example, imaging conditions with the console4and instructs the console4to start imaging, the console4turns on the sequence start signal that instructs the imaging apparatus3and the additional apparatus6to start an imaging sequence. Then, the console4transmits the sequence start signal to the imaging apparatus3and the additional apparatus6(Step S8). The sequence start signal can be transmitted using, for example, the information signal which is transmitted and received between the console4and the additional apparatus6and the information signal which is transmitted and received between the additional apparatus6and the imaging apparatus3.

If the imaging apparatus3and the additional apparatus6detect that the sequence start signal has been turned on, they start preparation for imaging.

In a case where the additional apparatus6is configured to transmit the timing signal in a stage before the irradiation instruction switch5is pressed, the additional apparatus6may perform control such that the reading instruction signal (seeFIG. 22) is turned on and the timing signal is repeatedly transmitted to the imaging apparatus3at predetermined intervals after it is detected that the sequence start signal has been turned on (Step S9).

The imaging apparatus3repeats the reading operation whenever the timing signal is received. Then, the temperature of the circuit in the imaging apparatus3rises. That is, the reading operation which is repeatedly performed by the imaging apparatus3in this stage is the warm-up of the imaging apparatus3.

In the initial stage in which the imaging apparatus3repeats the reading operation, the imaging apparatus3notifies the console4that a warm-up has started (Step S10).

The imaging apparatus3needs to perform a reading operation (reset operation) for removing the charge accumulated immediately before imaging.

Since the imaging apparatus3consumes power in the reading operation, the temperature of the imaging apparatus3rises with an increase in the power consumption. The sensitivity of a light receiver of the imaging device3is particularly changed by the temperature rise and image density based on the incident amount of radiation also changes. The change in image density due to the temperature rise is not a problem in a case where one still image is captured. However, in a case where dynamic imaging (for repeatedly capturing still images) is performed as in the system100according to this embodiment, the change in image density due to the temperature rise during imaging becomes a problem.

However, the above-mentioned configuration in which the imaging apparatus performs a warm-up makes it possible to reduce the change in image density due to the temperature rise.

The imaging apparatus3may acquire a correction image at any timing when Step S9is repeated a plurality of times.

For example, in a case where the imaging apparatus3is configured to perform a warm-up (to perform the reading operation before the irradiation instruction switch5is pressed), the imaging apparatus3may transmit an image which has been read in the second half of the warm-up as the correction image to the console4(Step S11).

A plurality of pixels of the imaging apparatus3have different characteristics and the charge levels corresponding to the brightness of the image are different in the pixels even when radiation is not emitted. Therefore, the image read in the second half of the warm-up is acquired as the correction image and, for example, each signal value of the correction image is subtracted from each signal value of a captured image which is obtained later to obtain a captured image in which a variation for each pixel has been removed.

In this embodiment, a case where the correction image is simply subtracted from the captured image has been described as an example of the method of using the correction image. However, noise components may be removed using various operations.

When the read operation (reset operation) for removing the charge accumulated immediately before imaging other than the acquisition of the correction image is performed, at least one of the following processes may be performed as the same operation as that in normal imaging:

a process of converting the removed charge into an image;

a process of storing the image data of the obtained image in the storage of the imaging apparatus3; and

a process of transmitting the imaged data or the image data stored in the storage of the imaging apparatus3to the console4.

The above-mentioned process which is the same as that in normal imaging is performed under the conditions close to those of actual imaging Therefore, according to this configuration, a difference in imaging in the subsequent steps is small and it is possible to reduce, for example, the influence of the temperature rise.

In contrast, in a case where the above-mentioned process which is the same as that in normal imaging is performed, the following problems arise:

the amount of power consumption increases;

since an unnecessary image obtained while no radiation is emitted is stored in the storage of the imaging apparatus3, the capacity of the storage that can be used at the time of imaging is reduced;

since the unnecessary image obtained while no radiation is emitted is transmitted to the console, the transmission of the unnecessary image occupies a part of communication capacity; and

since the unnecessary image is stored in the storage of the console, the capacity of the storage that can be used at the time of imaging is reduced.

Therefore, some of the processes may be omitted in order to avoid the problems.

The imaging apparatus3can be configured to complete the warm-up in a case where the number of reading operations as the warm-up reaches a predetermined value or the reading operation period has elapsed. For example, in Step S25(seeFIG. 12) in which the irradiation start signal is turned on, which will be described below, control is performed such that the irradiation start signal is not turned on until the number of reading operations reaches a predetermined value or the reading operation period elapses, which makes it possible not to start imaging using the emission of radiation until the warm-up is completed.

Then, the imaging apparatus3notifies the console4that preparation for imaging has been completed (Step S12).

At that time, “Imaging is available” may be displayed on the display43of the console4(Step S13).

C: Imaging Check

The additional apparatus6continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

If the radiographer ends the positioning of the subject and presses the irradiation instruction switch5to the first stage (Step S14), the irradiation instruction switch5turns on the irradiation preparation signal output to the radiation controller11through the console4(Step S15).

If the radiation controller11of the generation apparatus detects that the irradiation preparation signal has been turned on, it turns on the irradiation preparation signal output to the high voltage generator12and the additional apparatus6(Step S16). Then, the first acquirer62of the additional apparatus6acquires the irradiation preparation signal (which is output before the irradiation instruction signal and after the sequence start signal is turned on).

As such, the generation apparatus including the radiation controller11starts preparation for the emission of radiation in response to the irradiation preparation signal.

If the additional controller61of the additional apparatus6detects that the irradiation preparation signal from the radiation controller11has been turned on, it transmits the imaging preparation signal to the console4(Step S17).

In this case, the additional controller61or the console4may check again the following determination conditions (1) to (3).

(1) The set irradiation frame rate is a value corresponding to the generation apparatus.

(2) The set imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

If the above-mentioned relationship is not satisfied, the console4may prohibit an advance to the subsequent sequence or may not permit imaging.

The system may be configured to notify the radiographer of an error to warn the radiographer that the above-mentioned relationship is not satisfied when the above-described measures are taken.

If the console4receives the imaging preparation signal, it starts preparation for imaging. The preparation for imaging in the console4is, for example, an operation of checking whether the settings of the imaging apparatus control console42and the settings of the radiation control console41that controls the emission of radiation in the console4are the same or an operation of checking whether the designated imaging conditions are set in the imaging apparatus3.

If preparation for imaging is completed, the console4turns on the imaging preparation completion signal output to the additional apparatus6(Step S18).

At that time, “Imaging is being performed” may be displayed on the display43of the console4(Step S19).

In the stage in which the preparation for imaging has been completed, for example, the input of an instruction to change the imaging conditions to the console4may be locked such that the imaging conditions are not changed.

In a case where a still image is captured, imaging ends in a short time. Therefore, the risk of changing the imaging conditions during imaging is low and there is little need for this configuration. However, in the case of dynamic imaging, since the imaging period is long, there is a high risk that the radiographer or a third party other than the radiographer will intentionally or unintentionally operate the console screen to change the imaging conditions.

For this reason, in the process from this stage to the end of the sequence after Step S45which will be described below, the input of, for example, an instruction to change the imaging conditions to the console4is locked, which makes it possible to reliably prevent the change in the imaging conditions.

FIG. 5illustrates a case where the imaging preparation signal is output from the additional apparatus6to the console4. However, in some cases, the imaging preparation signal is not output to the console4, but is output to the imaging apparatus3such that the imaging apparatus3prepares imaging and the imaging preparation completion signal is output from the imaging apparatus3to the additional apparatus6after the imaging apparatus3completes preparation for imaging.

Further, in some cases, the imaging preparation signal is input to both the console4and the imaging apparatus3such that both the console4and the imaging apparatus3prepare imaging and the imaging preparation completion signal is output from the console4and the imaging apparatus3to the additional apparatus6after both the console4and the imaging apparatus3complete preparation for imaging. Then, it is determined that the entire preparation for imaging has been completed in a stage in which the additional apparatus6has received the imaging preparation completion signal from both the console4and the imaging apparatus3.

In a case where the radiation controller11of the generation apparatus has a connector that can input the imaging preparation completion signal indicating that preparation for imaging in the external device has been completed, the additional apparatus6may output the imaging preparation completion signal to the radiation controller11, which is not illustrated.

The radiation controller11detects that the imaging preparation completion signal from the additional apparatus6has been turned on to detect that the imaging apparatus3is in a state in which it can perform imaging Since the radiation control device1performs control such that radiation is emitted after it is detected that the imaging preparation completion signal has been turned on, it is possible to surely eliminate the risk that the imaging apparatus3will emit radiation while imaging is not possible and the subject will be unnecessarily exposed to radiation.

D: Execution of Imaging

Then, in a case where the radiographer presses the irradiation instruction switch5to the second stage (Step S20), the irradiation instruction switch5turns on the irradiation instruction signal transmitted to the radiation controller11through the console4(Step S21).

In this case, the additional apparatus6continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

Even in a case where the irradiation instruction signal is input from the irradiation instruction switch5, the radiation controller11of the generation apparatus does not transmit the irradiation signal to the high voltage generator12since the irradiation permission signal from the additional apparatus6is in an off state at this time.

The radiation controller11turns on the irradiation instruction signal transmitted to the additional controller61(Step S22).

If the additional apparatus6receives the irradiation instruction signal, it turns on the imaging start signal which notifies whether to permit the start of imaging and is output to the imaging apparatus3and the console4(Steps S23and S24).

In this case, the additional controller61or the console4may check again the following determination conditions (1) to (3).

(1) The set irradiation frame rate is a value corresponding to the generation apparatus.

(2) The set imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

If the above-mentioned relationship is not satisfied, the console4may prohibit an advance to the subsequent sequence or may not permit imaging.

The system may be configured to notify the radiographer of an error to warn the radiographer that the above-mentioned relationship is not satisfied when the above-described measures are taken.

If it is detected that the imaging start signal has been turned on, for example, the imaging apparatus3turns on the irradiation start signal output to the additional apparatus6, using the end of its reading operation performed at that time as a trigger, as illustrated inFIG. 12(Step S25). The reason is as follows. The reading operation of the imaging apparatus3sequentially reads the charge accumulated in the pixels which are two-dimensionally arranged to acquire the image of the entire light receiving surface. If the irradiation start signal is turned on to emit radiation during the reading operation, there is a difference between the signal value of the pixel from which the reading of charge has been completed and the signal value of the pixel from which the reading of charge has not been completed. As a result, image quality is significantly degraded.

In contrast, in this embodiment, the emission of radiation and the image reading operation of the imaging apparatus3are performed on the basis of the irradiation permission signal and the timing signal from the additional apparatus6, which will be described below. Therefore, the emission of radiation during the reading operation does not occur in a normal routine. Thus, the irradiation start signal may be turned on, without considering the reading timing of the imaging apparatus3.

The imaging apparatus3repeats the image reading operation even after the irradiation start signal is turned on. The image read after the irradiation start signal is turned on is stored as the captured image in the memory of the imaging apparatus3or is transmitted to the console4.

If the additional apparatus6detects that the irradiation start signal from the imaging apparatus3has been turned on, it detects that the imaging apparatus3is in a state in which the imaging apparatus3can perform imaging and repeatedly transmits the irradiation permission signal to the radiation controller11(Step S26).

In a case where the irradiation frame rate and the imaging frame rate are set such that the ratio of the irradiation frame rate to the imaging frame rate is 1:N, the additional controller61outputs the imaging permission signal once whenever it transmits the timing signal N times (FIG. 12illustrates a case where N is 2).

The radiation controller11of the generation apparatus repeatedly transmits the irradiation signal to the high voltage generator12since the imaging instruction signal and the irradiation permission signal are aligned whenever the irradiation permission signal is received.

Whenever the irradiation signal is received, the high voltage generator12repeatedly generates a high voltage required for emitting radiation and repeatedly outputs the high voltage as an irradiation output to the radiation generator2.

The radiation generator2repeatedly emits radiation to the imaging apparatus3whenever the irradiation output is input (Step S27).

The emitted radiation is transmitted through the subject (not illustrated) disposed between the imaging apparatus3and the radiation generator2and is then incident on the imaging apparatus3.

Whenever the timing signal is received, the imaging apparatus3repeats a process of accumulating the amount of charge corresponding to the intensity of the incident radiation (Step S28) and reading the charge as a captured image (Step S29).

The imaging apparatus3continuously repeats accumulation and reading. Whenever accumulation and reading are repeated N times, the imaging apparatus3is irradiated with radiation from the generation apparatus once and generates an exposed image.

The imaging apparatus3transmits the read radiographic image to the console4(Step S30).

In a case where the captured image is configured to be transmitted to the console4and is not transmitted to the console4in time due to the amount of data or a communication environment, some of a plurality of captured images or a part of one captured image may be stored in the imaging apparatus3and the rest may be transmitted to the console4.

An example of the operation of the imaging apparatus3will be further described. Here, a case where the accumulation of charge starts in response to the timing signal will be described.

Reset Operation/Correction Image Acquisition Operation

In the reset operation performed before imaging, the imaging apparatus3can repeat the above-mentioned operation while there is no radiation emitted from the radiation generation apparatus to output the charge (a dark charge or a dark current) which has been accumulated in each pixel and is not based on the emission of radiation, thereby resetting the charge which has been accumulated in each pixel, is not based on the emission of radiation, and is a noise component with respect to the image obtained by the charge based on the emission of radiation. Further, in the reset operation, control may be performed which the reader34does not convert the input charge into image data (operation before t1).

In the correction image acquisition operation performed before or after imaging, the imaging device3can repeat the above-mentioned operation while there is no radiation emitted from the radiation generation apparatus to output the charge (a dark charge or a dark current) which has been accumulated in each pixel and is not based on the emission of radiation, thereby resetting the charge which has been accumulated in each pixel, is not based on the emission of radiation, and is a noise component with respect to the image obtained by the charge based on the emission of radiation. In the correction image acquisition operation, the reader34converts the input charge into image data and the image data is stored. Therefore, it is possible to store a noise component while radiation is not emitted and to remove the noise component by subtracting the noise component from the image data obtained while radiation is emitted. The correction image acquisition operation may be performed as a part of the reset operation (operation before t1).

Operation of Ending Reset Operation/Correction Image Acquisition Operation

If the irradiation instruction signal in Step S21is turned on following the reset operation or the correction image acquisition operation, the imaging start signal input to the imaging apparatus3is turned on (Step S23). Then, the imaging apparatus3stops the reset operation or the correction image acquisition operation.

In a case where the correction image acquisition operation has not completed the acquisition of a predetermined number of correction images even though the imaging start signal has been turned on, the correction image acquisition operation is not stopped and is continuously performed until a predetermined number of correction images are acquired. Then, the correction image acquisition operation is stopped.

If the reset operation or the correction image acquisition operation is stopped, the imaging apparatus3stops the reset operation or the correction image acquisition operation and turns on the irradiation start signal in Step S25to notify that the imaging apparatus3is in a state in which it can perform imaging (t1).

Operation

If the imaging apparatus3receives the timing signal from the additional controller61, it applies the off-voltage to each scanning line32band changes to a state in which the charge generated by the radiation detection element32dcan be accumulated in the pixel, as illustrated inFIG. 14(t2, t6, t10, . . . ).

The additional controller61outputs the irradiation permission signal at the timing that is operatively associated with the timing when the timing signal is transmitted. The radiation generation apparatus irradiates the imaging apparatus3with radiation in response to the irradiation permission signal (Step S27; t3, t7, t11, . . . ).

In a case where the irradiation frame rate is 1/N times the imaging frame rate (FIG. 14illustrates a case where N is 2), the additional controller61outputs the irradiation permission signal once whenever it repeatedly outputs the timing signal N times. As a result, whenever the imaging apparatus3repeats accumulation and reading N times in response to the timing signal and the irradiation permission signal, the radiation generation apparatus emits radiation once (Step S27; t3, t11, . . . ). At that time, radiation is not emitted at the other timings (t7, . . . ).

The imaging apparatus3continues the mode for accumulating charge for a predetermined period of time, using a timer provided in the imaging apparatus3(t2to t4, t6to t8, t10to t12, . . . ).

If the imaging apparatus3receives radiation in the mode for accumulating charge, each radiation detection element32dof the radiation detector32generates charge and the charge is accommodated in each pixel (Step S28).

Then, the imaging apparatus3performs the reading operation which applies the on-voltage to each switching element32eafter the predetermined period of time elapses using the timer provided in the imaging apparatus3to output the charge accumulated in each pixel to the signal line32c. In the reading operation of the imaging apparatus3, the reader34reads the input charge and converts the charge into image data. In addition, the imaging apparatus3transmits at least a part of the image data to the console4(Steps S29and S30; t4to t5, t8to t9, t12to t13, . . . ).

Another Embodiment of Operation Control Method

The example in which the imaging apparatus changes to a state in which it can accumulate charge in the pixels in response to the timing signal from the additional controller61has been described above. However, control may be performed such that the imaging apparatus performs other operations in response to the timing signal.

For example, another control method may perform control such that, after the imaging apparatus3ends the reading operation (t4to5, t8to t9, t12to t13, . . . ) of discharging the charge accumulated in each pixel to the signal line32c, the imaging apparatus3changes to a state (t6to t8, t10to t12, . . . ) in which it can accumulate charge in the pixels, without waiting for the timing signal from the additional controller61.

Then, the additional controller61performs control such that the timing signal is output at the timing which is operatively associated with the timing when the radiation generation apparatus transmits the irradiation permission signal for radiation emission control.

The imaging apparatus3changes to the reading operation that outputs the charge accumulated in each pixel to the signal line32cin response to the received timing signal (t4, t8, t12, . . . ).

The repetition of the above-mentioned operation control makes it possible to perform imaging while matching the radiation emission timing of the radiation generation apparatus and the image generation timing of the imaging apparatus.

E: End of Imaging

The additional apparatus6counts the number of times the irradiation permission signal is transmitted from the time when the emission of radiation starts and determines whether the number of captured images reaches a predetermined maximum value whenever the number of times the irradiation permission signal is transmitted is counted. If it is determined that the counted number of times the irradiation permission signal is transmitted (the number of captured images) reaches the maximum number of captured images, the additional apparatus6turns off the imaging start signal (Step S31) and stops the output of the timing signal or/and the irradiation permission signal, as illustrated inFIG. 13.

Control may be performed such that the imaging apparatus3performs the operation of accumulating the amount of charge corresponding to the intensity of the incident radiation (Step S28) and reading the charge as a captured image (Step S29) at least once after the additional apparatus6outputs the irradiation permission signal last. In this case, it is possible to reliably read the image obtained by the last emission of radiation, to use the read image as the captured image, and to reliably prevent the subject from being unnecessarily exposed to radiation.

In addition, control may be performed such that the imaging apparatus3performs the operation of accumulating charge (Step S28) and reading the charge as a captured image (Step S29) after the additional apparatus6outputs the irradiation permission signal last, and then performs the operation of accumulating charge and reading the charge as a captured image. Since the captured image is an image captured while no radiation is emitted, these images can be used to correct the images captured in a case where radiation is emitted, similarly to the correction image.

In other words, for the 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, the correction images captured before and after imaging using radiation may be used. In this case, the correction images captured before and after imaging using radiation may be used to predict a change in the correction image during imaging and the correction image may be generated on the basis of the prediction result. The correction image can be generated, for example, by averaging the correction images captured before and after radiography or by performing linear or curve compensation for fluctuations.

In a case where a still image is captured, since the time required for imaging is short, a change in the correction images before and after imaging is small. However, in the case of dynamic imaging, the time required for imaging is longer than that in a case where a still image is captured. Therefore, in a case where the correction images before and after imaging are used as described above, it is possible to perform correction, also considering fluctuations during imaging.

The number of captured images may not be counted on the basis of the number of times the irradiation permission signal is transmitted as described above, but may be counted on the basis of the number of times the timing signal is output after the start of imaging.

In addition, the number of captured images may not be counted on the basis of the number of times the irradiation permission signal is transmitted as described above, but may be counted on the basis of the time elapsed since the start of imaging.

If it is detected that the imaging start signal has been turned off and imaging after radiation is emitted or imaging for acquiring the correction image ends, the imaging apparatus3turns off the reading instruction signal (seeFIG. 22) and transmits the images remaining in the memory of the imaging apparatus3(the captured images which have not been transmitted) to the console4(Step S32). Then, when the transmission of the remaining images is completed, the imaging apparatus3transmits the remaining image transmission completion signal to the console4(Step S33).

If the console4detects that the imaging start signal has been turned off, it starts an operation of checking the transmitted captured image.

If the console4receives the remaining image transmission completion signal, it transmits an image deletion signal for instructing the deletion of an image to the imaging apparatus3(Step S34).

Control may be performed such that the image deletion signal is transmitted after the captured image check operation is completed and it is checked that there is no problem in all of the transmitted images.

At that time, “End of imaging” may be displayed on the display43of the console4(Step S35).

If the imaging apparatus3receives the image deletion signal, it deletes the captured images stored in the memory (Step S36). Therefore, the free space of the memory can be ensured for the next imaging.

If the radiographer who has checked the end of imaging (for example, who has seen “End of imaging” displayed on the console4) releases the second stage of the irradiation instruction switch5(Step S37), the irradiation instruction switch5turns off the irradiation instruction signal (Step S38) and the radiation controller11also turns off the irradiation instruction signal (Step S39).

Then, if the radiographer releases the first stage of the irradiation instruction switch5(Step S40), the irradiation instruction switch5turns off the irradiation preparation signal (Step S41) and the radiation controller11also turns off the irradiation preparation signal (Step S42).

If the additional apparatus6detects that the irradiation preparation signal has been turned off, it notifies the console4that the irradiation preparation signal has been turned off.

If the console4receives the notification from the additional apparatus6, it turns off the imaging preparation completion signal and changes a sequence state to an irradiation preparation state.

If the additional apparatus6detects 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 apparatus3and the console4(Steps S43and S44).

If the imaging apparatus3receives the imaging end signal, it transmits a standby signal to the console4(Step S45).

If the console4receives the standby signal, it monitors the presence and absence of re-imaging or another imaging is performed for a predetermined period. If there is no re-imaging or another imaging for a predetermined period, the console4turns off the sequence start signal to change the sequence state to a standby state in which it waits for an imaging instruction.

In this way, a series of imaging operations ends.

The system100according to this embodiment operates as described above and dynamic imaging that repeatedly captures a plurality of still images in a short time is performed.

Selection of Image after Imaging

Then, the console4extracts only exposed images from a plurality of frames including every N exposed images which form the obtained dynamic image and have been captured at the timing when radiation is emitted (N−1 unexposed images generated without emitting radiation are interposed between the exposed images) and uses the extracted exposed images as a new dynamic image, which makes it possible to obtain a dynamic image with a radiation exposure of 1/N.

The extraction of the exposed image may be performed on the basis of the set irradiation frame rate, the imaging frame rate, and the frame number assigned to the dynamic image or may be performed by determining the pixel value of a predetermined pixel of each frame.

When the exposed image is extracted, an image correction process may be performed for the exposed image, using an unexposed image generated at the timing other than the timing when the exposed image is generated, if necessary.

Effect

In radiography systems that include a radiation generation apparatus capable of generating radiation and a radiography apparatus capable of generating a radiographic image based on the received radiation and can capture a dynamic image having a series of radiographic images as each frame, in recent years, a radiography system has been proposed which can perform imaging while switching the frame rate to a desired frame rate among a plurality of different frame rates.

For example, JP 2005-287773 A discloses a technique in which, while a radiography apparatus repeats charge accumulation and reading a predetermined number of times, a radiation generation apparatus emits radiation a number of times that is less than a predetermined value (thins out some of the radiation) such that the frame rate is less than usual and imaging is performed in this state. In addition, JP 2005-287773 A discloses a technique in which a controller controls the emission of radiation, accumulation, and reading and a thinned-out image generated at the timing when radiation is not emitted is used for correction.

Some radiography systems can use a plurality of cassette-type radiography apparatuses according to various situations. In these systems, in a case where the frame rate is switched according to the situation as in JP 2005-287773 A, for example, there is a problem that it is difficult to perform imaging since the frame rate designated by the radiographer does not correspond to at least one of the radiography apparatus and the radiation generation apparatus to be used, which does not occur in a case where imaging is performed with a fluoroscopic apparatus in which a combination of a radiation generation apparatus and an imaging apparatus is fixed.

In particular, in a situation in which the frame rate designated by the radiographer corresponds to the radiation generation apparatus, but does not correspond to the radiography apparatus, even though the radiation generation apparatus emits radiation in imaging, the radiography apparatus is not capable of performing accumulation and reading at that timing. Therefore, there is a risk that the subject will be unnecessarily exposed to radiation.

That is, in the imaging in which, while the radiography apparatus repeats charge accumulation and reading a predetermined number of times, the radiation generation apparatus emits radiation a number of times that is less than a predetermined value, it is necessary to reliably prevent the risk of starting imaging in a state in which the frame rate that does not correspond to at least one of the radiography apparatus and the radiation generation apparatus is set.

In order to solve the problems, in the system100according to the second embodiment, the additional controller61is connected to the radiation control device1which can perform the emission of radiation only once in response to one radiation emission instruction in the conventional system100A illustrated inFIG. 1such that the radiation control device1can output an irradiation signal a plurality of times in response to one irradiation instruction signal acquisition (turn-on detection) operation. That is, the generation apparatus can repeatedly generate radiation with a predetermined period. Therefore, it is possible to perform imaging which repeatedly generates a frame based on the received radiation with a predetermined period using the imaging apparatus3, that is, dynamic imaging.

The conventional system100A illustrated inFIG. 1is widely used as a system that can capture a simple still image. Therefore, a medical institution using the conventional system100A can easily modify the conventional system100A including the existing generation apparatus so as to respond to the dynamic imaging only by adding the imaging apparatus3and the additional apparatus6, without updating the expensive generation apparatus.

The system100according to this embodiment notifies the radiographer of the result of determining whether the irradiation frame rate acquired by the additional controller61or the console4is N times the acquired imaging frame rate (where N is an integer equal to or greater than 1) in a manner that the radiographer can recognize the determination result. Therefore, in the imaging in which, while the imaging apparatus3repeats charge accumulation and reading a predetermined number of times, the generation apparatus emits radiation a number of times that is equal to or less than a predetermined value, it is necessary to reliably prevent the risk of starting imaging in a state in which the frame rate that does not correspond to at least one of the imaging apparatus3and the generation apparatus is set.

Modification Example 1

The example in which all of the captured images are transmitted from the imaging apparatus3to the console4and the console4extracts necessary images (exposed images) and generates a dynamic image has been described above. However, all of the captured images may not be transmitted to the console4and the imaging apparatus3selects an exposed image or an unexposed image generated at other timings and transmits the selected image to the console4. In addition, the imaging apparatus3may perform an image correction process for the exposed image if necessary.

Modification Example 2: Imaging Apparatus3Counts Number of Captured Images

In the above-described embodiments, the example in which the additional apparatus6counts the number of times the irradiation permission signal is transmitted and determines that the number of images reaches the maximum value when the counted number of times the irradiation permission signal is transmitted reaches the maximum number of captured images has been described. However, an apparatus configuration may be used which counts the number of times the imaging apparatus3receives the timing signal after the irradiation start signal is transmitted, the number of times the imaging apparatus3receives the timing signal and performs reading, the number of times the imaging apparatus3performs reading and stores an image, or the number of times the image is transmitted to the console4and determines whether the counted number of times reaches the maximum number of captured images.

Modification Example 3: Permission of Imaging According to State of Imaging Apparatus

When the imaging apparatus3, the console4, and the additional apparatus6are connected or when imaging starts, it may be determined whether the designated dynamic imaging can be performed until the end with reference to the remaining power or remaining memory capacity of the imaging apparatus3.

If the imaging is possible on the basis of the determination result, information indicating that the imaging is possible may be displayed.

If the imaging is not possible on the basis of the determination result, information indicating that the imaging is not possible may be displayed.

Modification Example 4: Operation of Radiation Controller in Dynamic Imaging

In the above-described embodiments, the radiation controller11receives the irradiation instruction signal from the irradiation instruction switch5and repeatedly receives the irradiation permission signal from the additional controller61.

For example, the irradiation permission signal is transmitted as a pulse signal corresponding to the emission of radiation for capturing each frame of a dynamic image to the radiation controller11. Then, the radiation controller11transmits the irradiation signal to the high voltage generator12in response to each of the repeatedly received irradiation permission signals on a one-to-one basis such that radiation is emitted.

In a case where one still image is captured, it is sufficient for the radiation controller11to perform one irradiation permission signal transmission operation in response to one irradiation instruction signal reception operation.

In order to capture a still image, even if the irradiation permission signal is received a plurality of times in response to one irradiation instruction signal, radiation should not be emitted a plurality of times. Therefore, the radiation controller11may be configured to transmit the irradiation signal only once in response to the first input of the irradiation permission signal even if the irradiation permission signal is received a plurality of times in response to one irradiation instruction signal.

However, in a case where the radiation controller11transmits the irradiation signal only once in response to one irradiation permission signal as described above, it is difficult to perform dynamic imaging by repeatedly emitting radiation a plurality of times in response to one irradiation instruction signal as in the system100according to this embodiment.

Therefore, the radiation controller11may be configured to transmit the irradiation signal a plurality of times to the high voltage generator12in a case where the irradiation permission signal is received a plurality of times for one irradiation instruction signal input period, for which the radiographer presses the irradiation instruction switch5.

In this case, the emission of radiation is repeatedly performed a plurality of times in response to one irradiation instruction signal to perform dynamic imaging.

The control mode (1) in which the irradiation signal is transmitted only once in response to one irradiation permission signal and the control mode (2) in which the irradiation signal is transmitted to the high voltage generator12a plurality of times in response to the input of the irradiation permission signal in a case where the irradiation permission signal is input a plurality of times for the irradiation instruction signal input period may be switched according to the type of imaging (whether imaging is the capture of a still image or dynamic imaging).

The console4can switch the control mode of the radiation controller11according to the type of imaging. Alternatively, the control mode may be changed on the basis of the reception of a signal indicating the type of imaging from the console4.

This configuration makes it possible to reliably prevent the risk that radiation will be erroneously emitted a plurality of times when a still image is captured and the subject will be unnecessarily exposed to radiation.

Modification Example 5: Limit of Timing of Radiation Controller in Dynamic Imaging

For example, in a case where electrical noise is mixed in the irradiation permission signal transmitted from the additional controller61to the radiation controller11and the radiation controller11receives the same signal as the irradiation permission signal at an unintended timing, the same situation as that in which the irradiation permission signal is repeatedly received at intervals that are so short that the high voltage generator12does not generate the high voltage required for emitting radiation in time is likely to occur. If the radiation controller11forcibly transmits the irradiation signal to the high voltage generator12, it is likely that an excessive current will flow through the high voltage generator12and the high voltage generator12will be out of order.

In the above-described embodiments, the radiation controller11may be configured as follows: in a case where the irradiation permission signal is repeatedly received from the additional controller61while the irradiation instruction signal input from the irradiation instruction switch5is in an on state, the radiation controller11compares the length of the reception interval of two consecutive irradiation permission signals with a predetermined minimum reception interval and does not transmits the irradiation signal to the high voltage generator12in a case where it is determined that the reception interval is shorter than the minimum reception interval.

This configuration makes it possible to prevent the high voltage generator12from being out of order due to the flow of an excessive current to the high voltage generator12.

Conventional Technology 2

Conventional Technology 2 which is the basis of systems200(will be described in detail below) according to third and fourth embodiments of the invention will be described with reference toFIG. 15. The same configurations as those in Conventional Technology 1 are denoted by the same reference numerals and the description thereof will not be repeated.

System Configuration

First, the schematic configuration of a radiography system (hereinafter, referred to as a conventional system200A) according to Conventional Technology 2 will be described.FIG. 15is a block diagram illustrating the schematic configuration of the conventional system200A.

For example, as illustrated inFIG. 15, the conventional system200A differs from the conventional system100A in the configuration of a radiation controller11A of a radiation control device1A.

Specifically, the radiation controller11of the conventional system100A is configured to output the irradiation preparation signal and the irradiation instruction signal from the radiation control console41to an external apparatus on the basis of the detection of the turn-on of the irradiation preparation signal or the irradiation instruction signal. However, the radiation controller11A of the conventional system200A does not have this configuration.

In addition, the radiation controller11of the conventional system100A is configured to receive the irradiation permission signal from the external apparatus. However, the radiation controller11A of the conventional system200A does not have this configuration.

Operation

The operation of the conventional system200A will be described.

Irradiation Preparation Operation

If the radiographer presses the irradiation instruction switch5to the first stage, the irradiation instruction switch5turns on the irradiation preparation signal output to the radiation controller11A through the radiation control console41.

If it is detected that the irradiation preparation signal has been turned on, the radiation controller11A turns on the irradiation preparation signal output to the high voltage generator12.

FIG. 15does not illustrate the output of the irradiation preparation signal from the radiation controller11A to an external apparatus. However, in a case where the radiation controller11A cooperates with the external apparatus, it may output the irradiation preparation signal to the external apparatus.

If the high voltage generator12detects that the irradiation preparation signal has been turned on, it outputs the irradiation preparation output to the radiation generator2.

If the irradiation preparation output is input, the radiation generator2starts preparation for generating radiation.

In a case where an anode is a rotating anode, for example, an operation of rotating the rotating anode is performed.

Irradiation Operation

Then, if the radiographer presses the irradiation instruction switch to the second stage, the irradiation instruction switch5turns on the irradiation instruction signal output to the radiation controller11A through the radiation control console41.

FIG. 15does not illustrate the output of the irradiation instruction signal from the radiation controller11A to the external apparatus. However, in a case where the radiation controller11A cooperates with the external apparatus, it may output the irradiation instruction signal to the external apparatus.

In Conventional Technology 2, since the irradiation permission signal is not received from the external apparatus, the control process of transmitting the irradiation signal in a case where the irradiation instruction signal is aligned with the irradiation permission signal is not performed. Therefore, the radiation controller11A transmits the irradiation signal to the high voltage generator12on the basis of only the detection of the turn-on of the irradiation instruction signal.

If the high voltage generator12receives the irradiation signal, it applies a high voltage required for the radiation generator2to emit radiation as an irradiation output to the radiation generator2.

If the high voltage generator12applies the high voltage, the radiation generator2generates radiation corresponding to the applied voltage.

For example, the irradiation direction, irradiation region, and quality of the generated radiation are adjusted by a controller (not illustrated), such as a collimator, and the adjusted radiation is emitted to the subject and the cassette3A behind the subject. A portion of the radiation passes through the subject and is then incident on the cassette3A.

If the radiation is incident on the cassette3A, a radiographic image is formed on a film or a fluorescent plate provided in the cassette3A.

Similarly to Conventional Technique1, the radiation controller11A may be configured not to transmit the irradiation signal until a predetermined standby time elapses from the detection of the turn-on of the irradiation preparation signal even if the turn-on of the irradiation instruction signal has been detected, in order to prevent radiation from being emitted before the rotating anode reaches a sufficient rotation speed.

As such, in radiography using the conventional system200A, only one radiographic image (still image) of the subject is captured on the basis of one imaging operation, similarly to a case where the conventional system100A is used.

Third Embodiment

The third embodiment of the invention will be described with reference toFIGS. 16 to 18. The same configurations as those in the first and second embodiments are denoted by the same reference numerals and the description thereof will not be repeated. In addition, various modification patterns described in the first and second embodiments may also be applied to this embodiment.

Premise, Background, and Task

There is a radiography system including the radiation controller11illustrated in Conventional Technology 1 which has an input port for the irradiation permission signal from the outside and transmits the irradiation signal according to the irradiation instruction from the radiographer and the irradiation permission from the outside. In addition, there is a radiography system including the radiation controller11A illustrated in Conventional Technology 2 which has only an input port for the irradiation instruction signal from the outside and captures a still image.

A radiography system (hereinafter, referred to as a system200) according to this embodiment is configured such that an additional apparatus6A is added to the radiation controller11A to continuously perform imaging

System Configuration

First, the system configuration of the radiography system200will be described.FIG. 16is a block diagram illustrating the schematic configuration of the system200according to the third embodiment.

For example, as illustrated inFIG. 16, the system200according to the invention differs from the conventional system200A (seeFIG. 15) in that the imaging apparatus3replaces the cassette3A and the system200further includes the same imaging apparatus control console42as that in the first and second embodiments and the additional apparatus6A.

The additional apparatus6A includes an additional controller61A and an interface (hereinafter, referred to as an I/F67).

FIG. 16illustrates an example in which the additional apparatus6A is divided into the additional controller61A and the I/F67. However, the additional controller61A and the I/F67may be integrated.

The additional controller61A includes a third connector66in addition to the first acquirer62, the second acquirer63, the first connector64, and the second connector65which are the same as those in the first and second embodiments.

The I/F67includes a first AND circuit67aand a second AND circuit67b.

The first acquirer62is connected to one input terminal of the first AND circuit67aand the third connector66is connected to the other input terminal of the first AND circuit67a.

The second acquirer63is connected to one input terminal of the second AND circuit67band the second connector65is connected to the other input terminal of the second AND circuit67b.

In the system100according to the first and second embodiments, the irradiation instruction switch5is connected to the console4and outputs the irradiation preparation signal or the irradiation instruction signal to the additional apparatus6through the radiation control device1. However, in the system200according to this embodiment, the irradiation instruction switch5that can output the irradiation preparation signal or the irradiation instruction signal is directly connected to the additional apparatus6A.

The additional apparatus6A is configured such that the irradiation preparation signal or the irradiation instruction signal from the irradiation instruction switch5can be input to the additional controller61A and the one input terminal of each of the first and second AND circuits67aand67bof the I/F67. That is, the first acquirer62can directly acquire the irradiation preparation signal from the irradiation instruction switch5and the second acquirer63can directly acquire the irradiation instruction signal from the irradiation instruction switch5.

In addition, a substrate or an apparatus provided with the irradiation instruction switch5may be connected to the I/F67and the first and second acquirers62and63may acquire the irradiation preparation signal or the irradiation instruction signal output from the irradiation instruction switch5through the substrate or the apparatus.

The third connector66according to this embodiment outputs an imaging preparation completion signal to the first AND circuit67aand the second connector65outputs the irradiation permission signal to the second AND circuit67b. In a case where the AND conditions of the input signals with the irradiation preparation signal and the irradiation instruction signal from the irradiation instruction switch5are established in the first and second AND circuits67aand67b, the irradiation preparation signal and the irradiation instruction signal can be output to the radiation controller11through the radiation control console41.

That is, the second connector65according to this embodiment can be connected to the radiation generation apparatus through the I/F67. Therefore, the I/F67or the radiation control console41according to this embodiment form a relay according to the invention.

FIG. 16illustrates an example in which the irradiation preparation signal from the irradiation instruction switch5is branched by the I/F67so as to be input to the additional controller61A and the first AND circuit67aand the irradiation preparation signal is output from the I/F67in a case where the AND condition of the irradiation preparation signal and the imaging preparation completion signal from the additional controller61A is established. However, this configuration may not be applied to the irradiation preparation signal and the irradiation preparation signal may be directly output from the irradiation instruction switch5to the radiation control console41or the radiation controller11A.

In addition,FIG. 16illustrates a configuration in which the third connector66directly transmits and receives information or signals to and from the imaging apparatus3. However, the third connector66may be connected to another apparatus through a relay (not illustrated) that can relay signals.

Further,FIG. 16illustrates a case where the first acquirer62, the second acquirer63, the first connector64, and the second connector65are separately provided. However, at least two of the first acquirer62, the second acquirer63, the first connector64, the second connector65, and the third connector66may be integrated (the components62to66may be shared).

The irradiation preparation signal and the irradiation instruction signal output from the additional apparatus6A may be directly input to the radiation controller11A without passing through the radiation control console41, which is not illustrated.

A program executed by the additional controller61A may be different from that executed by the additional controller61according to the first and second embodiments and the structure of the additional controller61A may be different from that of the additional controller61according to the first and second embodiments (the additional controller61according to the first and second embodiments also has the third connector66and a command for using the third connector66may not be included in the program such that the same additional controller as the additional controller61can be used, which is not illustrated inFIG. 16). Alternatively, an additional controller61A that is limited to necessary functions may be used separately from the additional controller61.

If the additional controller61A detects that the irradiation preparation signal from the irradiation instruction switch5has been turned on, it turns on the imaging preparation signal output to at least one of the imaging apparatus3and the console4.

If the additional controller61A detects that the imaging preparation completion signal from at least one of the console4and the imaging apparatus3has been turned on, it turns on the imaging preparation completion signal output to the other input terminal of the first AND circuit67aof the I/F67.

If the additional controller61A detects that the irradiation instruction signal from the irradiation instruction switch5has been turned on, it turns on the imaging start signal output to at least one of the imaging apparatus3and the console4.

If the additional controller61A detects that the irradiation start signal from at least one of the console4and the imaging apparatus3has been turned on, it repeatedly outputs the same irradiation permission signal (for example, a pulse signal) as that in the first and second embodiments to the other input terminal of the second AND circuit67bof the I/F67with a predetermined period.

The additional controller61A repeatedly outputs the same timing signal (for example, a pulse signal) as that in the first and second embodiments to the imaging apparatus3with a predetermined period.

The additional controller61A may be configured to include the same timer as that in the first and second embodiments in order to control the transmission timing of the irradiation permission signal or the timing signal as described above.

In some cases, a plurality of generation apparatuses are connected to the system200as illustrated inFIG. 4, similarly to the system100according to the first and second embodiments. In this case, one of the generation apparatuses is selected and used.

Similarly, in some cases, a plurality of imaging apparatuses3are connected to the system200. In this case, one of the imaging apparatuses is selected and used.

The additional apparatus6A includes the additional controller61A and the interface (Hereinafter, referred to as the I/F67).

FIG. 16illustrates an example in which the additional apparatus6A is divided into the additional controller61A and the I/F67. However, the additional controller61A and the I/F67may be integrated.

The additional controller61A includes the third connector66in addition to the first acquirer62, the second acquirer63, the first connector64, and the second connector65which are the same as those in the first and second embodiments.

The I/F67includes the first AND circuit67aand the second AND circuit67b.

The first acquirer62is connected to one input terminal of the first AND circuit67aand the third connector66is connected to the other input terminal of the first AND circuit67a.

The second acquirer63is connected to one input terminal of the second AND circuit67band the second connector65is connected to the other input terminal of the second AND circuit67b.

In the system100according to the first and second embodiments, the irradiation instruction switch5is connected to the console4and outputs the irradiation preparation signal or the irradiation instruction signal to the additional apparatus6through the radiation control device1. However, in the system200according to this embodiment, the irradiation instruction switch5that can output the irradiation preparation signal or the irradiation instruction signal is directly connected to the additional apparatus6A.

The additional apparatus6A is configured such that the irradiation preparation signal or the irradiation instruction signal from the irradiation instruction switch5can be input to the additional controller61A and the one input terminal of each of the first and second AND circuits67aand67bof the I/F67. That is, the first acquirer62can directly acquire the irradiation preparation signal from the irradiation instruction switch5and the second acquirer63can directly acquire the irradiation instruction signal from the irradiation instruction switch5.

In addition, a substrate or an apparatus provided with the irradiation instruction switch5may be connected to the I/F67and the first and second acquirers62and63may acquire the irradiation preparation signal or the irradiation instruction signal output from the irradiation instruction switch5through the substrate or the apparatus.

The third connector66according to this embodiment outputs the imaging preparation completion signal to the first AND circuit67aand the second connector65outputs the irradiation permission signal to the second AND circuit67b. In a case where the AND conditions of the input signals with the irradiation preparation signal and the irradiation instruction signal from the irradiation instruction switch5are established in the first and second AND circuits67aand67b, the irradiation preparation signal and the irradiation instruction signal can be output to the radiation controller11through the radiation control console41.

That is, the second connector65according to this embodiment can be connected to the generation apparatus through the I/F67. Therefore, the I/F67or the radiation control console41according to this embodiment form the relay according to the invention.

FIG. 16illustrates the example in which the irradiation preparation signal from the irradiation instruction switch5is branched by the I/F67so as to be input to the additional controller61A and the first AND circuit67aand the irradiation preparation signal is output from the I/F67in a case where the AND condition of the irradiation preparation signal and the imaging preparation completion signal from the additional controller61A is established. However, this configuration may not be applied to the irradiation preparation signal and the irradiation preparation signal may be directly output from the irradiation instruction switch5to the radiation control console41or the radiation controller11A.

In addition,FIG. 16illustrates the configuration in which the third connector66directly transmits and receives information or signals to and from the imaging apparatus3. However, the third connector66may be connected to another apparatus through a relay (not illustrated) that can relay signals.

Further,FIG. 16illustrates a case where the first acquirer62, the second acquirer63, the first connector64, and the second connector65are separately provided. However, at least two of the first acquirer62, the second acquirer63, the first connector64, the second connector65, and the third connector66may be integrated (the components62to66may be shared).

The irradiation preparation signal and the irradiation instruction signal output from the additional apparatus6A may be directly input to the radiation controller11A without passing through the radiation control console41, which is not illustrated.

A program executed by the additional controller61A may be different from that executed by the additional controller61according to the first and second embodiments and the structure of the additional controller61A may be the same as that of the additional controller61according to the first and second embodiments (the additional controller61according to the first and second embodiments also has the third connector66and a command for using the third connector66may not be included in the program such that the same additional controller as the additional controller61can be used, which is not illustrated inFIG. 16). Alternatively, an additional controller61A that is limited to necessary functions may be used separately from the additional controller61.

If the additional controller61A detects that the irradiation preparation signal from the irradiation instruction switch5has been turned on, it turns on the imaging preparation signal output to at least one of the imaging apparatus3and the console4.

If the additional controller61A detects that the imaging preparation completion signal from at least one of the console4and the imaging apparatus3has been turned on, it turns on the imaging preparation completion signal output to the other input terminal of the first AND circuit67aof the I/F67.

If the additional controller61A detects that the irradiation instruction signal from the irradiation instruction switch5has been turned on, it turns on the imaging start signal output to at least one of the imaging apparatus3and the console4.

If the additional controller61A detects that the irradiation start signal from at least one of the console4and the imaging apparatus3has been turned on, it repeatedly outputs the same irradiation permission signal (for example, a pulse signal) as that in the first and second embodiments to the other input terminal of the second AND circuit67bof the I/F67with a predetermined period.

The additional controller61A repeatedly outputs the same timing signal (for example, a pulse signal) as that in the first and second embodiments to the imaging apparatus3with a predetermined period.

The additional controller61A may be configured to include the same timer as that in the first and second embodiments in order to control the transmission timing of the irradiation permission signal or the timing signal as described above.

Operation

The operation of the system200will be described.FIGS. 17 and 18are ladder charts illustrating the operation of the system200according to this embodiment.

As illustrated inFIG. 17, the following are the same as those in the first and second embodiments.

A: operations when an apparatus is installed, when an apparatus starts up, when the connected apparatus is changed, and when the connected apparatus is periodically checked (Steps S1and S2)

B: an operation in preparation for imaging (Steps S3to S13)

The additional apparatus6A continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation of the imaging apparatus3whenever the timing signal is received.

If the radiographer ends the positioning of the subject and presses the irradiation instruction switch5to the first stage (Step S14), the irradiation instruction switch5turns on the irradiation preparation signal output to the additional apparatus6A (Step S15A).

The irradiation preparation signal is input to the additional controller61A and the one input terminal of the first AND circuit67aof the I/F67.

In this case, the additional controller61A is connected to the other input terminal of the first AND circuit67a. Therefore, in a case where the imaging preparation completion signal input to the other input terminal of the first AND circuit67ais not turned on even though the irradiation preparation signal input from the irradiation instruction switch5to the one input terminal of the first AND circuit67ais turned on, the irradiation preparation signal output from the first AND circuit67ato the radiation control console41is maintained in the off state.

If the additional controller61A detects that the irradiation preparation signal from the irradiation instruction switch5has been turned on, it transmits the imaging preparation signal for instructing preparation for imaging to at least one of the console4and the imaging apparatus3(Step S17).

If at least one of the console4and the imaging apparatus3receives the imaging preparation signal, it prepares imaging. If the preparation for imaging is completed, the at least one of the console4and the imaging apparatus3turns on the imaging preparation completion signal output to the additional apparatus6A (Step S18).

Control of Preparation for Imaging in External Apparatus

In a case where at least one of the console4and the imaging apparatus3has a connector for inputting the imaging preparation completion signal indicating whether preparation for imaging has been completed from an external apparatus, which is not illustrated, if at least one of the console4and the imaging apparatus3detects that the imaging preparation completion signal from the external apparatus has been turned on, it may turn on the imaging preparation completion signal.

Alternatively, the additional apparatus6A or the additional controller61A may be provided with a connector for outputting the imaging preparation signal to an external apparatus or a connector that can input the imaging preparation completion signal from an external apparatus, which is not illustrated.

In this case, the additional apparatus6A or the additional controller61A can instruct the external apparatus to prepare imaging, or can detect the completion of preparation for imaging in the external apparatus and output the imaging preparation completion signal to the I/F in response to the completion of preparation for imaging in the external apparatus.

The additional apparatus6A detects that the imaging preparation completion signal has been turned on to know that at least one of the console4and the imaging apparatus3or the external device is in a state in which it can perform imaging. The additional apparatus6A performs control such that radiation is emitted after the imaging preparation completion signal is turned on. Therefore, it is possible to surely eliminate the risk that at least one of the console4and the imaging apparatus3or the external apparatus will emit radiation while imaging is not possible and the subject will be unnecessarily exposed to radiation.

If at least one of the console4and the imaging apparatus3detects that the imaging preparation signal has been turned on, enters an imaging preparation operation, or completes the imaging preparation operation, it turns on a signal indicating whether the imaging preparation signal has been received, a signal indicating whether the imaging preparation operation has started, or an imaging preparation completion signal indicating whether the imaging preparation operation has been completed (Step S18). In this case, the turned-on signal is transmitted to the additional apparatus6A.

If the additional apparatus6A detects that the imaging preparation completion signal has been turned on, it turns on the imaging preparation completion signal output to the other input terminal of the first AND circuit67aof the I/F67.

In this case, since both the irradiation preparation signal input to the first AND circuit67aof the I/F67from the irradiation instruction switch5and the imaging preparation completion signal from the additional controller61A are turned on, the first AND circuit67aturns on the irradiation preparation signal output to the radiation control console41.

If the radiation control console41detects that the irradiation preparation signal has been turned on, it turns on the irradiation preparation signal output to the radiation controller11A (radiation generation apparatus). That is, the additional apparatus6A turns on the irradiation preparation signal transmitted to the radiation generation apparatus through the radiation control console41(Step S18A).

If the radiation generation apparatus (the radiation controller11A, the high voltage generator12, and the radiation generator2) detects that the irradiation preparation signal has been turned on, it prepares the emission of radiation as in the first and second embodiments.

A case where the additional apparatus6A checks the completion of preparation for imaging in the imaging apparatus3or the console4(receives the imaging preparation completion signal) and then transmits the irradiation preparation signal to the radiation controller11A has been described above. However, the additional apparatus6A may transmit the irradiation preparation signal to the imaging apparatus3or the console4and the radiation controller11A at the same time, without checking the completion of preparation for imaging in the imaging apparatus3or the console4.

In this case, the first AND circuit67aof the I/F67is not necessary and the irradiation preparation signal received from the irradiation instruction switch5may be distributed to each of the console4, the imaging apparatus3, the radiation control console41, and the radiation controller11A.

D: Execution of Imaging

If the radiographer presses the irradiation instruction switch5to the second stage (Step S20), the irradiation instruction switch5turns on the irradiation instruction signal transmitted to the additional apparatus6A (Step S21A).

In this case, the additional apparatus6A continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

The irradiation instruction signal is input to each of the additional controller61A and the one input terminal of the second AND circuit67bof the I/F67.

In this case, the additional controller61A is connected to the other input terminal of the second AND circuit67b. Therefore, in a case where the irradiation permission signal is not input to the other input terminal of the second AND circuit67beven though the irradiation instruction signal input from the irradiation instruction switch5to the one input terminal of the first AND circuit67bis turned on, the irradiation instruction signal output from the second AND circuit67bto the radiation control console41is maintained in the off state.

If the additional apparatus6A detects that the irradiation instruction signal from the irradiation instruction switch5has been turned on, it turns on the imaging start signal output to at least one of the console4and the imaging apparatus3(Steps S23and S24).

If it is detected that the imaging start signal has been turned on, for example, the imaging apparatus3turns on the irradiation start signal output to the additional apparatus6A, using the end of its reading operation performed at that time as a trigger, as illustrated inFIG. 18(Step S25).

If the additional controller61A detects that the irradiation start signal from the imaging apparatus3has been turned on, it determines that the imaging apparatus3is in a state in which the imaging apparatus3can perform imaging and repeatedly inputs the irradiation permission signal to the other input terminal of the second AND circuit67bof the I/F67whenever the timing signal is transmitted to the imaging apparatus3.

In this case, since both the irradiation instruction signal input from the irradiation instruction switch5to the second AND circuit67bof the I/F67and the irradiation permission signal input from the additional controller61A to the second AND circuit67bof the I/F67are turned on, the second AND circuit67brepeatedly transmits the irradiation instruction signal to the radiation controller11A through the radiation control console41(Step S26A).

An operation (Step S27to S30) in the second half of “D: Execution of imaging” and an operation (Step S31to S36) in the first half of “E: End of Imaging” are the same as those in the first and second embodiments.

End of Imaging

In a case where the radiographer who has checked the end of imaging releases the second stage of the irradiation instruction switch5(Step S37), the irradiation instruction switch5turns off the irradiation instruction signal (Step S38A). Then, the imaging apparatus3turns off the imaging start signal.

Then, in a case where the radiographer releases the first stage of the irradiation instruction switch5(Step S40), the irradiation instruction switch5turns off the irradiation preparation signal (Step S41A).

Steps S43to S45are the same as those in the first and second embodiments.

In this way, a series of imaging operations ends.

The system200according to this embodiment operates as described above to perform dynamic imaging which repeatedly captures a plurality of still images in a short time, similarly to the system100according to the first and second embodiments.

Effect

As described above, the system200according to this embodiment is configured by connecting the additional controller61A to the radiation control device1that can perform only one radiation emission operation in response to one radiation emission instruction in the conventional system200A illustrated inFIG. 15. Therefore, the radiation control device1can output the irradiation signal a plurality of times in response to one irradiation instruction (the pressing of the irradiation instruction switch5to the second stage). As a result, it is possible to perform imaging that repeatedly captures still images a plurality of times in a short time using the imaging apparatus3, that is, dynamic imaging.

The conventional system200A illustrated inFIG. 15is widely used as a radiography apparatus that captures a simple still image. Therefore, a medical institution using the conventional system200A can easily modify the conventional system200A including the existing radiation generation apparatus so as to respond to the dynamic imaging only by adding the imaging apparatus3and the additional apparatus6A, without updating the expensive radiation generation apparatus.

The system200according to this embodiment may be configured such that the additional apparatus6A is divided into the additional controller61A and the I/F67and the additional controller61A has the same structure as the additional controller61in the first and second embodiments (except for only the stored program). In this case, it is possible to manufacture the additional apparatus6according to the first and second embodiments and the additional apparatus6A according to the third embodiment (to modify the conventional system100A and the conventional system200A) using common components, without increasing the type of apparatus.

In the third embodiment, the configuration in which the additional apparatus6A is added to the conventional system200A illustrated inFIG. 15such that dynamic imaging can be performed has been described. However, the embodiment of the invention is not limited thereto. For example, the additional apparatus6A according to the third embodiment may be added to the conventional system100A illustrated inFIG. 1such that dynamic imaging can be performed.

For example, the conventional system100A illustrated inFIG. 1can be used as the radiography system according to the invention by keeping the irradiation permission signal input to the radiation controller11of the conventional system100A illustrated inFIG. 1in an on state.

According to this configuration, dynamic imaging can be performed by adding the additional apparatus to various types of radiography systems.

Fourth Embodiment

A fourth embodiment of the invention will be described with reference toFIGS. 16, 17, 19, and 20. The same configurations as those in the first to third embodiments are denoted by the same reference numerals and the description thereof will not be repeated. In addition, various modification patterns described in the first to third embodiments may also be applied to this embodiment.

Premise, Background, and Task

There is a radiography system including the radiation controller11illustrated in Conventional Technology 1 which has an input port for the irradiation permission signal from the outside and transmits the irradiation signal according to the irradiation instruction from the radiographer and the irradiation permission from the outside. In addition, there is a radiography system including the radiation controller11A illustrated in Conventional Technology 2 which has only an input port for the irradiation instruction signal from the outside and captures a still image.

A radiography system (hereinafter, referred to as a system200) according to this embodiment is configured such that the additional apparatus6A is added to the radiation controller11A to continuously perform imaging

System Configuration

First, the system configuration of the radiography system200will be described.FIG. 16is a block diagram illustrating the schematic configuration of the system200according to the fourth embodiment.

For example, as illustrated inFIG. 16, the system200according to the invention differs from the conventional system200A (seeFIG. 15) in that the imaging apparatus3replaces the cassette3A and the system200further includes the same imaging apparatus control console42as that in the first to third embodiments and the additional apparatus6A.

Operation

The operation of the system200will be described.FIGS. 17, 19, and 20are ladder charts illustrating the operation of the system200according to this embodiment.

As illustrated inFIG. 17, the following are the same as those in the first to third embodiments.

A: Operations when an apparatus is installed, when an apparatus starts up, when the connected apparatus is changed, and when the connected apparatus is periodically checked” (Steps S1and S2)

B: an operation in preparation for imaging (Steps S3to S13)

That is, in the system200according to this embodiment, similarly to the system100according to the first to third embodiments, imaging can be performed even in a case where a combination of the generation apparatus and the imaging apparatus3is changed. Therefore, it is possible to select a cassette-type imaging apparatus3suitable for an imaging order or an imaging technique from a plurality of cassette-type imaging apparatuses3with different sizes or performances and to perform imaging with the selected imaging apparatus3.

In this case, for example, as illustrated inFIG. 8, an imaging apparatus3that is suitable for the current imaging is selected from a plurality of imaging apparatuses3that can be connected to the console4and can be used for imaging and imaging is performed using the selected imaging apparatus.

In the system100in which a plurality of generation apparatuses are connected to one console4which is not illustrated, a generation apparatus used for imaging is selected and imaging is performed using the selected generation apparatus.

If at least one of the generation apparatus and the imaging apparatus3is selected, the additional controller61A of the additional apparatus6A or the console4according to this embodiment can acquire the irradiation frame rate or the imaging frame rate.

The additional controller61A or the console4can also acquire the imaging frame rate.

The irradiation frame rate or the imaging frame rate to be acquired may be input (selected) to the console4by the radiographer or may be received from the generation apparatus or the imaging apparatus3.

In a case where the irradiation frame rate or the imaging frame rate is received from the generation apparatus or the imaging apparatus3, one frame rate selected in each apparatus may be received or all of a plurality of frame rates corresponding to each apparatus may be received.

It is necessary to satisfy all of the following determination conditions (1) to (3) in order to perform imaging without any problem.

(1) The acquired irradiation frame rate is a value corresponding to the generation apparatus.

(2) The acquired imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

Therefore, the additional controller61A or the console4determines whether all of the determination conditions are satisfied.

Here, the “irradiation frame rate” indicates the number of times radiation is generated by the generation apparatus per unit time and corresponds to the transmission period of the irradiation permission signal by the additional controller61A.

The “imaging frame rate” indicates the number of times a radiographic image is generated by the imaging apparatus3per unit time and corresponds to the transmission period of the timing signal by the additional controller61A.

In a case where at least one of the number of irradiation frame rates and the number of imaging frame rates is two or more, there are a plurality of combinations of the irradiation frame rates and the imaging frame rates. Therefore, determination may be performed a plurality of times in accordance with the plurality of combinations.

Here, N is an integer equal to or greater than 1. However, for example, in a case where imaging is performed while thinning out radiation at predetermined intervals, it is preferable that N is an integer equal to or greater than 2.

In a case where at least one of the number of imaging frame rates received from the imaging apparatus3and the number of irradiation frame rates received from the generation apparatus is two or more, there may be a plurality of combinations of the imaging frame rates and the irradiation frame rates. Therefore, it may be determined in advance whether each combination satisfies all of the above-mentioned determination conditions.

In a case where the generation apparatus or the imaging apparatus is configured to select only the corresponding irradiation frame rate or the corresponding imaging frame rate, the generation apparatus, the imaging apparatus3, or the console4can omit the determination of whether the determination conditions (1) and (2) are satisfied.

If any of the determination conditions is not satisfied as a result of checking whether all of the determination conditions are satisfied, at least one of the following measures (4) to (6) may be taken.

(4) Among the imaging apparatus3used, the generation apparatus used, the imaging frame rate of the imaging apparatus3, and the irradiation frame rate of the generation apparatus, a component that does not satisfy the above-mentioned relationship is not selected or an input value is not received (not set).

(5) A setting candidate that does not satisfy the above-mentioned relationship is grayed out (display to notify the determination result is performed) and is excluded from a selection target such that it is not selectable.

(6) Even in a case where a component can be selected, it does not advance to the next sequence. Alternatively, imaging is not permitted.

When the above-described measures are taken, the system may notify the photographer of an error to warn the photographer that the relationship is not satisfied. In this embodiment, the warning may be performed by voice or may be performed by display for notifying the determination result using the display43.

The additional apparatus6A continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

In a case where the radiographer ends the positioning of the subject and presses the irradiation instruction switch5to the first stage (Step S14), the irradiation instruction switch5turns on the irradiation preparation signal output to the additional apparatus6A (Step S15A).

The irradiation preparation signal is input to the additional controller61A and the one input terminal of the first AND circuit67aof the I/F67.

In this case, the additional controller61A is connected to the other input terminal of the first AND circuit67a. Therefore, in a case where the imaging preparation completion signal input to the other input terminal of the first AND circuit67ais not turned on even though the irradiation preparation signal input from the irradiation instruction switch5to the one input terminal of the first AND circuit67ais turned on, the irradiation preparation signal output from the first AND circuit67ato the radiation control console41is maintained in the off state.

If the additional controller61A detects that the irradiation preparation signal from the irradiation instruction switch5has been turned on, it transmits the imaging preparation signal for instructing preparation for imaging to at least one of the console4and the imaging apparatus3(Step S17).

In this case, the additional controller61A or the console4may check again the following determination conditions (1) to (3).

(1) The set irradiation frame rate is a value corresponding to the generation apparatus.

(2) The set imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

If the above-mentioned relationship is not satisfied, the console4may prohibit an advance to the subsequent sequence or may not permit imaging.

The system may be configured to notify the radiographer of an error to warn the radiographer that the above-mentioned relationship is not satisfied when the above-described measures are taken.

If at least one of the console4and the imaging apparatus3receives the imaging preparation signal, it prepares imaging. If the preparation for imaging is completed, the at least one of the console4and the imaging apparatus3turns on the imaging preparation completion signal output to the additional apparatus6A (Step S18).

Control of Preparation for Imaging in External Apparatus

In a case where at least one of the console4and the imaging apparatus3has a connector for inputting the imaging preparation completion signal indicating whether preparation for imaging has been completed from an external apparatus, which is not illustrated, if at least one of the console4and the imaging apparatus3detects that the imaging preparation completion signal from the external apparatus has been turned on, it may turn on the imaging preparation completion signal.

Alternatively, the additional apparatus6A or the additional controller61A may be provided with a connector for outputting the imaging preparation signal to an external apparatus or a connector that can input the imaging preparation completion signal from an external apparatus, which is not illustrated.

In this case, the additional apparatus6A or the additional controller61A can instruct the external apparatus to prepare imaging, or can detect the completion of preparation for imaging in the external apparatus and output the imaging preparation completion signal to the I/F in response to the completion of preparation for imaging in the external apparatus.

The additional apparatus6A detects that the imaging preparation completion signal has been turned on to know that at least one of the console4and the imaging apparatus3or the external device is in a state in which it can perform imaging. The additional apparatus6A performs control such that radiation is emitted after the imaging preparation completion signal is turned on. Therefore, it is possible to surely eliminate the risk that at least one of the console4and the imaging apparatus3or the external apparatus will emit radiation while imaging is not possible and the subject will be unnecessarily exposed to radiation.

If at least one of the console4and the imaging apparatus3detects that the imaging preparation signal has been turned on, enters an imaging preparation operation, or completes the imaging preparation operation, it turns on a signal indicating whether the imaging preparation signal has been received, a signal indicating whether the imaging preparation operation has started, or an imaging preparation completion signal indicating whether the imaging preparation operation has been completed (Step S18). In this case, the turned-on signal is transmitted to the additional apparatus6A.

If the additional apparatus6A detects that the imaging preparation completion signal has been turned on, it turns on the imaging preparation completion signal output to the other input terminal of the first AND circuit67aof the I/F67.

In this case, since both the irradiation preparation signal input from the irradiation instruction switch5to the first AND circuit67aof the I/F67and the imaging preparation completion signal from the additional controller61A are turned on, the first AND circuit67aturns on the irradiation preparation signal output to the radiation control console41.

If the radiation control console41detects that the irradiation preparation signal has been turned on, it turns on the irradiation preparation signal output to the radiation controller11A (generation apparatus). That is, the additional apparatus6A turns on the irradiation preparation signal transmitted to the generation apparatus through the radiation control console41(Step S18A).

If the generation apparatus (the radiation controller11A, the high voltage generator12, and the radiation generator2) detects that the irradiation preparation signal has been turned on, it prepares the emission of radiation as in the first to third embodiments.

A case where the additional apparatus6A checks the completion of preparation for imaging in the imaging apparatus3or the console4(receives the imaging preparation completion signal) and then transmits the irradiation preparation signal to the radiation controller11A has been described above. However, the additional apparatus6A may transmit the irradiation preparation signal to the imaging apparatus3or the console4and the radiation controller11A at the same time, without checking the completion of preparation for imaging in the imaging apparatus3or the console4.

In this case, the first AND circuit67aof the I/F67is not necessary and the irradiation preparation signal received from the irradiation instruction switch5may be distributed to each of the console4, the imaging apparatus3, the radiation control console41, and the radiation controller11A.

D: Execution of Imaging

Then, in a case where the radiographer presses the irradiation instruction switch5to the second stage (Step S20), the irradiation instruction switch5turns on the irradiation instruction signal transmitted to the additional apparatus6A (Step S21A).

In this case, the additional apparatus6A continues to repeatedly transmit the timing signal to the imaging apparatus3and the imaging apparatus3repeats the reading operation whenever the timing signal is received.

The irradiation instruction signal is input to each of the additional controller61A and the one input terminal of the second AND circuit67bof the I/F67.

In this case, the additional controller61A is connected to the other input terminal of the second AND circuit67b. Therefore, in a case where the irradiation permission signal is not input to the other input terminal of the second AND circuit67beven though the irradiation instruction signal input from the irradiation instruction switch5to the one input terminal of the first AND circuit67bis turned on, the irradiation instruction signal output from the second AND circuit67bto the radiation control console41is maintained in the off state.

In a case where the additional apparatus6A detects that the irradiation instruction signal from the irradiation instruction switch5has been turned on, it turns on the imaging start signal output to at least one of the console4and the imaging apparatus3(Steps S23and S24).

In this case, the additional controller61A or the console4may check again the following determination conditions (1) to (3).

(1) The set irradiation frame rate is a value corresponding to the generation apparatus.

(2) The set imaging frame rate is a value corresponding to the imaging apparatus3.

(3) The ratio of the irradiation frame rate to the imaging frame rate is 1:N, where N is an integer equal to or greater than 1 (the imaging frame rate is N times the irradiation frame rate).

If the above-mentioned relationship is not satisfied, the console4may prohibit an advance to the subsequent sequence or may not permit imaging.

The system may be configured to notify the radiographer of an error to warn the radiographer that the above-mentioned relationship is not satisfied when the above-described measures are taken.

If it is detected that the imaging start signal has been turned on, for example, the imaging apparatus3turns on the irradiation start signal output to the additional apparatus6A, using the end of its reading operation performed at that time as a trigger, as illustrated inFIG. 19(Step S25).

If the additional controller61A detects that the irradiation start signal from the imaging apparatus3has been turned on, it determines that the imaging apparatus3can perform imaging and repeatedly inputs the irradiation permission signal to the other input terminal of the second AND circuit67bof the I/F67whenever the timing signal is transmitted to the imaging apparatus3.

In this case, since both the irradiation instruction signal input from the irradiation instruction switch5to the second AND circuit67bof the I/F67and the irradiation permission signal input from the additional controller61A to the second AND circuit67bof the I/F67are turned on, the second AND circuit67brepeatedly transmits the irradiation instruction signal to the radiation controller11A through the radiation control console41(Step S26A).

In a case where the ratio of the irradiation frame rate to the imaging frame rate is set to 1:N, the additional controller61A outputs the imaging permission signal once whenever the timing signal is output N times (FIG. 19illustrates a case where N is 2).

The imaging apparatus3continues to repeatedly perform accumulation and reading Whenever the imaging apparatus3repeatedly performs accumulation and reading N times, it is irradiated with radiation from the generation apparatus once to generate an exposed image.

An operation (Step S27to S30) in the second half of “D: Execution of imaging” and an operation (Step S31to S36) in the first half of “E: End of Imaging” are the same as those in the first to third embodiments.

End of Imaging

If the radiographer who has checked the end of imaging releases the second stage of the irradiation instruction switch5(Step S37), the irradiation instruction switch5turns off the irradiation instruction signal (Step S38A). Then, the imaging apparatus3turns off the imaging start signal.

Then, if the radiographer releases the first stage of the irradiation instruction switch5(Step S40), the irradiation instruction switch5turns off the irradiation preparation signal (Step S41A).

Steps S43to S45are the same as those in the first to third embodiments.

In this way, a series of imaging operations ends.

The system200according to this embodiment operates as described above to perform dynamic imaging which repeatedly captures a plurality of still images in a short time, similarly to the system100according to the first to third embodiments.

Effect

As described above, the system200according to this embodiment is configured by connecting the additional controller61A to the radiation control device1that can perform only one radiation emission operation in response to one radiation emission instruction in the conventional system200A illustrated inFIG. 15. Therefore, the radiation control device1can output the irradiation signal a plurality of times in response to one irradiation instruction (the pressing of the irradiation instruction switch5to the second stage). As a result, it is possible to perform imaging that repeatedly captures still images a plurality of times in a short time using the imaging apparatus3, that is, dynamic imaging.

The conventional system200A illustrated inFIG. 15is widely used as a system that captures a simple still image. Therefore, a medical institution using the conventional system200A can easily modify the conventional system200A including the existing generation apparatus so as to respond to the dynamic imaging only by adding the imaging apparatus3and the additional apparatus6A, without updating the expensive generation apparatus.

The system200according to this embodiment may be configured such that the additional apparatus6A is divided into the additional controller61A and the I/F67and the additional controller61A has the same structure as the additional controller61in the first to third embodiments (except for only the stored program). In this case, it is possible to manufacture the additional apparatus6according to the first to third embodiments and the additional apparatus6A according to the fourth embodiment (to modify the conventional system100A and the conventional system200A) using common components, without increasing the type of apparatus.

The system200according to this embodiment notifies the radiographer of the result of determining whether the irradiation frame rate acquired by the console4is N times the acquired imaging frame rate (where N is an integer equal to or greater than 1) in a manner that the radiographer can recognize the determination result. Therefore, in the imaging in which, while the imaging apparatus3repeats charge accumulation and reading a predetermined number of times, the generation apparatus emits radiation a number of times that is equal to or less than a predetermined value, it is necessary to reliably prevent the risk of starting imaging in a state in which the frame rate that does not correspond to at least one of the imaging apparatus3and the generation apparatus is set.

In the fourth embodiment, the configuration in which the additional apparatus6A is added to the conventional system200A illustrated inFIG. 15such that dynamic imaging can be performed has been described. However, the embodiment of the invention is not limited thereto. For example, the additional apparatus6A according to the fourth embodiment may be added to the conventional system100A illustrated inFIG. 1such that dynamic imaging can be performed.

For example, the conventional system100A illustrated inFIG. 1can be used as the radiography system according to the invention by keeping the irradiation permission signal input to the radiation controller11of the conventional system100A illustrated inFIG. 1always in an on state.

According to this configuration, dynamic imaging can be performed by adding the additional apparatus to various types of radiography systems.

In the description of the first to fourth embodiments, various functions of the additional controller61or the console4may be included not in the additional controller61or the console4but in the radiation control device1or the imaging apparatus3.

The example in which the systems100and200according to the first to fourth embodiments are configured by modifying the conventional systems100A and200A using the additional apparatuses6and6A has been described. However, the invention is not limited to these types of radiography systems. For example, a radiography system which does not include the additional apparatus6or6A and includes the imaging apparatus3or the radiation control device1or1A having a dynamic imaging function may be used.

In this case, for example, the console4, the radiation control device1, or the imaging apparatus3has various functions.

Sequence State Change

A sequence state change operation of the systems100and200according to the first to fourth embodiments will be described with reference toFIGS. 21 and 22.

Premise, Background, and Task

The systems100and200according to the first and second embodiments are not capable of correctly performing imaging unless the connected apparatuses operate in a correct order.

Even if an error unintended by the radiographer, such as noise in a signal line or the cutting of a signal line, occurs, it is necessary to safely end imaging such that radiation is not unintentionally emitted.

Operation

First, the operation of the systems100and200will be described.FIG. 21is a state transition diagram illustrating a change in the state of the systems100and200andFIG. 22is a timing chart illustrating the operation of the systems100and200.

First, the systems100and200according to the embodiments are in a standby state St′ in which in which the imaging start instruction is not received from the radiographer as illustrated inFIG. 21.

If the console4receives an imaging order from the host system7, such as RIS or HIS, and the radiographer selects the imaging order, the console4turns on the sequence start signal output to the imaging apparatus3and the additional apparatus6or6A as illustrated inFIG. 22(t1).

Then, the imaging apparatus3and the additional apparatus6or6A starts preparation for imaging. Then, the system100or200changes to an irradiation preparation state St2as illustrated inFIG. 21.

In the irradiation preparation state St2, as illustrated inFIG. 22, the additional apparatus6or6A repeatedly transmits the timing signal to imaging apparatus3at a predetermined interval and the imaging apparatus3repeats the reading operation whenever the timing signal is received. In this way, the reset operation of removing the charge accumulated in the imaging apparatus3is repeatedly performed.

The reading operation performed here is the same as the operation in a case where a captured image is acquired. However, since the image acquired by the reset operation has been generated in the irradiation preparation state St2in which no radiation is emitted, the image may be stored in the memory of the imaging apparatus3or may be transmitted to the console4. Alternatively, the image may be removed without being stored or transmitted.

Since at least a portion of the image acquired by the reset operation indicates the characteristics of each pixel of the imaging apparatus3or the characteristics of the image of the imaging apparatus3, for example, the acquired image may be stored in the imaging apparatus3or may be transmitted to the console4as a correction image for correcting the captured image.

At least one of a plurality of images acquired by repeatedly performing the reset operation may be used as the correction image. Alternatively, the average of the signal values of the corresponding pixels in a plurality of images or a complementary estimate in the time direction may be calculated and used as the correction image.

As a method for correcting a captured image, for example, there is a method which subtracts the signal value of each pixel of the correction image from the image obtained by emitting radiation.

The system may be configured such that the timing signal can be transmitted to the imaging apparatus3in a state other than the irradiation preparation state St2. In addition, after the system changes to the irradiation preparation state St2, the reset operation instruction signal may be turned on such that the imaging apparatus3performs the reset operation only in a case where the reset operation instruction signal is turned on.

The radiographer sets, for example, imaging conditions with the imaging apparatus control console42or the radiation control console41, positions the subject, and then starts an imaging operation.

Specifically, as illustrated inFIG. 22, the radiographer operates the irradiation instruction switch5to turn on the irradiation preparation signal transmitted to the console4(t2). Then, the system100or200changes to an irradiation start state St3as illustrated inFIG. 21.

In the irradiation start state St3, the console4checks the state of the radiation control device1, the imaging apparatus3, and the additional apparatus6or6A. If it is determined that imaging is possible, the console4turns on the imaging preparation completion signal transmitted to the additional apparatus6or6A as illustrated inFIG. 21(t3).

The console4may check whether the imaging conditions set in the radiation control console41are the same as the imaging conditions set in the imaging apparatus control console42. If the imaging conditions are different from each other, the console4may display information indicating that the imaging conditions are different from each other.

In a case where the imaging conditions set in the radiation control console41are different from the imaging conditions set in the imaging apparatus control console42, control may be performed such that the process does not advance to the subsequent imaging sequence.

While the imaging preparation completion signal remains on, control may be performed that the imaging conditions set in the imaging apparatus control console42and the radiation control console41are not capable of being changed.

If the radiation control device1detects that the irradiation preparation completion signal has been turned on, it prepares the emission of radiation (t2). This is, for example, an operation of rotating the rotating anode of the radiation generator2.

If the additional apparatus6or6A detects that the irradiation preparation signal has been turned on, it starts to count the set timer (t2).

With this configuration, even in a case where the radiographer presses the irradiation instruction switch5to the second stage (turns on the irradiation instruction signal), the system is not capable of shifting to an irradiation standby state St4, which will be described below, until the timer counts a predetermined standby time.

Then, the radiographer presses the irradiation instruction switch5to the second stage to turn on the irradiation instruction signal (t4).FIG. 22illustrates a case where, after the imaging preparation completion signal is turned on, the irradiation instruction signal is turned on. However, before the imaging preparation completion signal is turned on, the irradiation instruction signal may be turned on.

If the additional controller61or61A confirms that the irradiation instruction signal has been turned on, that the imaging preparation completion signal has been turned on, and that a predetermined standby time of the timer has passed, the system100or200changes to the irradiation standby state St4as illustrated inFIG. 21.

In the irradiation standby state St4, the additional controller61or61A checks whether the imaging apparatus3is in a state in which it can perform imaging. The imaging apparatus3checks whether it can perform imaging. If it is determined that the imaging apparatus3can perform imaging, the imaging apparatus3transmits the irradiation start signal to the additional controller61or61A as illustrated inFIG. 22(t5).

For example, whether the imaging apparatus3can perform imaging is checked by determining whether the charge of the light receiver in the imaging apparatus3has been removed after the completion of a predetermined reset operation or whether the reset operation has been completed in all of the pixels of the light receiving surface (the reset operation is performed by scanning each row of the pixels arranged in a matrix on the light receiving surface).

If the additional controller61or61A detects that the irradiation start signal from the imaging apparatus3has been turned on, the system100or200changes to an irradiation permission state St5as illustrated inFIG. 21.

In the irradiation permission state St5, as illustrated inFIG. 22, the additional controller61or61A turns on the imaging start signal which is an internal interlock (t5) and repeatedly transmits the irradiation permission signal or the irradiation instruction signal to the radiation controller11or11A at a timing corresponding to the timing when the timing signal is output to the imaging apparatus3.

The radiation generation apparatus (the radiation controller11or11A, the high voltage generator12, and the radiation generator2) generates radiation whenever the irradiation permission signal or the irradiation instruction signal is received such that the radiation transmitted through the subject can be repeatedly incident on the imaging apparatus3.

In the irradiation permission state St5, after the irradiation start signal is turned on, the additional controller61or61A may perform control such that the number of captured images is counted whenever the timing signal or the irradiation permission signal is transmitted. In a case where the counted number of captured images reaches a set maximum value, the additional controller61or61A turns off the imaging start signal (t6) and the system100or200changes to an irradiation end state St6as illustrated inFIG. 21.

In a case where the irradiation permission signal is counted to count the number of captured image, it is necessary to read a captured image obtained by the last emission of radiation Therefore, the timing when the reading instruction signal may be delayed or the timing signal which corresponds to one frame and is a trigger for the read operation may be further transmitted. This configuration makes it possible to eliminate the risk that imaging will be continuously performed to capture images greater than the set maximum number of images and the subject will be irradiated with unnecessary radiation and will be exposed to radiation more than necessary.

If the radiographer releases the second stage of the irradiation instruction switch5, the irradiation instruction signal is turned off as illustrated inFIG. 22(t7).

If the radiographer releases the first stage of the irradiation instruction switch5, the irradiation preparation signal is turned off (t8).

If the additional controller61or61A confirms that all of the input signals have been reset, the system100or200changes to the irradiation preparation state St2illustrated inFIG. 21.

Here, “all of the signals” may be the irradiation preparation signal, the irradiation instruction signal, the imaging start signal which is the interlock of the additional controller61or61A, and the irradiation start signal of the imaging apparatus3.

If the radiographer determines that it is necessary to perform another imaging or that it is necessary to perform imaging again because the acquired captured image is not sufficient for the desired purpose as a result of the check of the captured image, the radiographer changes the state of the subject and the imaging conditions and performs imaging again according to the above-mentioned flow.

If it is determined that imaging is not necessary, the console4turns off the sequence start signal (t9) and ends the imaging sequence. Then, the system100or200changes to the standby state St′ as illustrated inFIG. 21.

In cases other than the above-mentioned case (the determination of the radiographer), if there is no input from the radiographer for a predetermined period of time, the system may change to the standby state St1.

Operation in Case where Imaging is not Continuously Performed

The flow of the above-mentioned state change occurs in a case where imaging is continuously performed until the number of captured images reaches the maximum value. However, in some cases, imaging is not capable of being continuously performed until the number of captured images reaches the maximum value according to various situations.

For example, in a case where the radiographer wants to interrupt imaging before the number of captured images reaches the maximum value, the radiographer releases the second stage of the irradiation instruction switch5to turn off the irradiation instruction signal. Then, the system100or200changes from the irradiation permission state St5to the irradiation end state St6. This is because one of a plurality of OR conditions for changing from the irradiation permission state St5to the irradiation end state St6illustrated inFIG. 21(the irradiation instruction signal from the irradiation instruction switch5is turned off, the irradiation start signal from the imaging apparatus3is turned off, and the imaging start signal from the additional apparatus6or6A is turned off) is established.

In the irradiation end state St6, the emission of radiation is stopped and then, for example, a process of transmitting the images remaining in the imaging apparatus3to the console4or a process of deleting the images transmitted and stored in the imaging apparatus3is performed similarly to a case where the number of captured images reaches the maximum value. The reason is as follows. Even if a specified number of images are not captured, the captured images may be used. In this case, the radiographer can check the captured images as in normal imaging.

It is necessary to manage the images which have not been captured to a specified number in association with the captured images. In a case where a specified number of images have not been captured, a note indicating that the specified number of images have not been captured may be added to each image or each aggregation of images and then the images or the image aggregations may be managed.

In the case where the specified number of images have not been captured, the console4may display information indicating that the specified number of images have not been captured on the basis of, for example, an error signal transmitted from the additional apparatus6or6A.

Operation in Case where Error Occurs

There is a case where the additional apparatus6or6A is disconnected from the imaging apparatus3during imaging.

For example, the following are considered as the cause of the disconnection:

in a case where the additional apparatus6or6A and the imaging apparatus3are connected to each other in a wired manner, a cable is detached from a connector; and,

in a case where the additional apparatus6or6A is wirelessly connected to the imaging apparatus3, radio crosstalk, a radio failure, and the cut-off of power to a wireless apparatus.

The system100or200may be configured to have a function of monitoring whether errors (error 1, error 2, error 3, and error 4) occur in each of the sequence states St3to St6. If an error is detected, the system100or200may change to an error state St7as represented by a dashed line inFIG. 21.

If the system changes to the error state St7, the content of the error causing the system to change to the error state St7may be displayed on, for example, the display43of the console4.

For the detection of the error, for example, an error monitoring sequence for monitoring signals in each state may be performed in parallel to the imaging sequence illustrated inFIG. 21. If an error is detected in the error monitoring sequence, the imaging sequence may be changed from the current sequence states St3to St6to the error state St7.

Alternatively, the operable time may be set in each of the sequence states St3to St6illustrated inFIG. 21. When the system changes to each of the sequence states St3to St6, the timer may start the measurement of the time to measure the operable time in each sequence state. If the operable time in each sequence state measured by the time has elapsed, control may be performed such that the sequence state changes to the error state St7.

If an error occurs, the additional apparatus6or6A or the imaging apparatus3that has detected the error may notify the console4of the occurrence of the error and the console4may display the occurrence of the error.

After the change to the error state St7, the sequence state is changed to the irradiation preparation state St2or the standby state St1, using the establishment of specific conditions (for example, the reset of the error and the reset of all signals) as a trigger.

Effect

This error detection method reliably detects a defect in the apparatus or the operation, changes the system to the error state, and returns the system to the standby state St′ or the irradiation preparation state St2during the imaging sequence if necessary. Therefore, the use of the error detection method makes it possible to reliably eliminate the risk that radiation will be emitted in a state in which a defect occurs in the apparatus or the operation and the subject will be unnecessarily exposed to radiation.

Specific examples in a case where the system100or200is achieved will be described.

Various techniques described here may also be applied to the conventional systems100A and200A.

Example 1: Integration of Additional Controller

Integration of Additional Controller into Radiation Control Device

In a case where the system100or200according to the above-described embodiments is installed in a medical institution such as a hospital, it is difficult to secure the place where the additional apparatus6or6A is installed separately from the radiation control device1according to the situation of the medical institution.

There is a radiation control device1having a space for an additional function as an option.

Therefore, the additional controller61or61A may not be provided as the additional apparatus6or6A independent of the radiation control device1, but may be provided in a radiation control device1B as illustrated in, for example, inFIG. 23.

For example, the additional controller61or61A may be provided in the form of a substrate.

In this case, the additional apparatus6or6A is not provided separately from the radiation control device1and the additional controller61or61A or an IF (which is provided if necessary) may be added to the conventional device that captures still images such that the system100or200can perform dynamic imaging.

It is possible to reduce wiring lines which are provided around each apparatus forming the system100or200and to reduce the risk that the wiring lines will hinder imaging and errors will occur in the operation of the system100or200due to noise from the wiring lines.

Example 2: Mobile Medical Cart

Configuration in Mobile Medical Cart

Many photographers want to perform dynamic imaging not only with a radiography system that is used in a room, but also with a mobile medical car that can be used while being moved in the medical institution.

Therefore, the configuration according to the above-described embodiments may be used for the conventional mobile medical cart that captures still images. That is, the additional apparatus6or6A may be provided in the housing of the mobile medical cart or may be added to the mobile medical cart such that it can be moved together with the mobile medical cart. As a result, the additional apparatus6or6A can operate integrally with the mobile medical cart.

At that time, the additional controller61or61A may be provided in the radiation control device1as described in Example 1.

This configuration makes it possible to perform dynamic imaging using the conventional mobile medical cart for capturing still images.

Example 3: Unification of Display

Input/Display of Information

In the systems100and200according to the above-described embodiments, each of the radiation control console41and the imaging apparatus control console42may have the display43. In this configuration, if different imaging conditions are displayed on the displays43of the consoles41and42, the photographer is not able to determine which imaging conditions are set in the radiation controller11or11A or the imaging apparatus3. In the worst case, there is a possibility that imaging will be performed under the imaging conditions that are not intended by the radiographer and the subject will be unnecessarily exposed to radiation.

Therefore, control may be performed such that the imaging conditions set in both the radiation control console41and the imaging apparatus control console42are the same and thus the same content is displayed on the displays43of both the radiation control console41and the imaging apparatus control console42. A specific example of the control for making the imaging conditions the same will be described in the following Example 4.

As a method other than the above-mentioned method, at least one of the radiation control console41and the imaging apparatus control console42may perform a process that checks whether the imaging conditions set in both the radiation control console41and the imaging apparatus control console42or the setting contents displayed on the displays43of both the radiation control console41and the imaging apparatus control console42are the same, using at least one of the detection of a specific operation and the passage of a specific period as a trigger.

At least one of the result of the process and a warning may be notified, the result indicating whether the setting contents or the display contents of the radiation control console41and the imaging apparatus control console42are the same, and the warning indicating that the setting contents or the display contents of the radiation control console41and the imaging apparatus control console42are different from each other.

In this configuration, even in a case where each of the radiation control console41and the imaging apparatus control console42has the display43, the same imaging conditions are set in both the radiation control console41and the imaging apparatus control console42or the same setting content is displayed on both the displays43. Therefore, the radiographer can check the imaging conditions set in the entire system100or200and it is possible to perform imaging under the imaging conditions intended by the radiographer.

Example 4: Matching of Input Results

Information Cooperation

In a case where, for example, the imaging conditions can be input from both the radiation control console41and the imaging apparatus control console42as in the first and second embodiments, the input results (setting contents) of the consoles41and42need to be matched with each other.

Therefore, for example, in a case where the conditions have been changed in one of the radiation control console41and the imaging apparatus control console42, the other console may be changed to the same settings by the following information cooperation methods (1) to (3).

Information Cooperation Method (1)

One of the radiation control console41and the imaging apparatus control console42is set as a master and the other console is set as a slave. Then, information is rewritten by the master and the slave only copies the information rewritten by the master.

Information Cooperation Method (2)

It is assumed that the information cooperation method is common to the radiation control console41and the imaging apparatus control console42.

Alternatively, the radiation control console41and the imaging apparatus control console42are provided with timers which are synchronized with each other. If there is an input, both the time information of the timer and the content of the input are stored. Then, imaging conditions are set in both the radiation control console41and the imaging apparatus control console42in chronological order of the input.

Information Cooperation Method (3)

If information is input, the information is rewritten in both the radiation control console41and the imaging apparatus control console42. Until rewriting is completed in both the radiation control console41and the imaging apparatus control console42, the next input is not received or the next input is stored. If rewriting is completed, the next input is rewritten.

This configuration makes it possible to input, for example, imaging conditions from both the radiation control console41and the imaging apparatus control console42. As a result, the convenience of the radiography system is improved.

It is possible to reliably match the input from one of the radiation control console41and the imaging apparatus control console42between the consoles41and42.

Example 5: Permission of Irradiation after it is Checked that Settings are the Same

Check of Information

In the first and second embodiments in which both the radiation control console41and the imaging apparatus control console42can input conditions, such as imaging conditions, and can display, for example, the imaging conditions, in a case where the conditions of the consoles41and42are not the same and imaging is performed under the imaging conditions set in one of the two consoles41and42, imaging is likely to be performed under the imaging conditions that are not intended by the radiographer.

Therefore, the radiation control console41and the imaging apparatus control console42may determine whether the recognize, set, or displayed imaging conditions are the same at a certain timing of the imaging sequence and may continue the imaging sequence in a case where they determines that the imaging conditions are the same.

If the imaging sequence is continued, information indicating that the imaging conditions are the same and there is no problem may be displayed.

In contrast, if it is determined that the imaging conditions are not the same in both the consoles, at least one of a process of performing control such that the continuation of the imaging sequence or the emission of radiation is not permitted or a process of displaying information indicating that the imaging conditions are not same may be performed.

In the above description, at least one of “the certain timings of the imaging sequence” may be, for example, the timing when the imaging conditions are set after the irradiation preparation signal is input or the timing when the check operation is performed, as illustrated inFIG. 22.

This configuration makes it possible to reliably match the imaging conditions of both the radiation control console41and the imaging apparatus control console42.

In addition, it is possible to reliably eliminate the risk that imaging will be performed under the imaging conditions set in either the radiation control console41or the imaging apparatus control console42in a state in which the imaging conditions are not the same.

Example 6: Preventing Imaging Conditions from Changing after Imaging Starts

Prohibition Period of Input/Change of Information

There is a possibility that imaging which is not intended by the radiographer will be performed in a case where the imaging conditions are changed from the radiation control console41or the imaging apparatus control console42during imaging, the change being not intended by the radiographer, even though the radiographer starts imaging in a state in which the imaging conditions are input from one of the radiation control console41and the imaging apparatus control console42and other imaging conditions are satisfied, using the above-mentioned technique.

Therefore, it may be configured that the imaging conditions cannot be changed from the radiation control console41and the imaging apparatus control console42after a certain timing of the imaging sequence.

Specifically, for example, the display screen is changed to a screen other than the input screen or the input screen is grayed out such that the photographing conditions are not capable of being input.

In the above description, at least one of “the certain timings of the imaging sequence” may be, for example, the timing when the imaging conditions are set after the irradiation preparation signal is input or the timing when the check operation is performed, as illustrated inFIG. 22.

This configuration makes it possible to reliably prevent a situation in which the imaging conditions are changed during imaging and imaging is performed under the imaging conditions that are not intended by the radiographer.

Example 7: Output Through Divided Wiring Lines

Wiring Method

There is a case where the existing radiography system for connecting the additional controller61or61A is modified in order to capture a still image. In addition, there is a case where the existing radiography system is modified in order to perform both still image capture and dynamic imaging.

In a case where the existing radiography system is modified in order to capture only still images, a wiring line for the timing signal is not necessary. Therefore, there is no problem. However, for example, in a case where the existing imaging table (for example, an upright imaging table or a decubitus imaging table) is used for imaging, the thickness of a wiring line that can be disposed in the apparatus to be resolved may be limited to the minimum thickness required for transmitting and receiving information for capturing a still image (for example, the thickness of a general-purpose LAN cable) due to curvature in the apparatus. If this apparatus is modified, the types of signals transmitted and received through the apparatus increase and the thickness of the wiring line increases. Therefore, there is a problem that it difficult to dispose the wiring line in the apparatus.

For this reason, for example, as illustrated inFIG. 24, signals lines extending from the additional controller61or61A to the imaging apparatus3may be divided into an information line, a power supply line, and a timing signal line and signals may be output through the divided lines.

Specifically, in a case where the conventional system is modified in order to capture only still images, the wire lines are arranged so as to be divided into two wiring lines (an information line and a power supply line).

In a case where the conventional system is modified in order to perform both still image capture and dynamic imaging, the wiring lines are arranged so as to be divided into three wiring lines (an information line, a power supply line, and a timing signal line).

In a case where the conventional system is modified in order to perform both still image capture and dynamic imaging, the wiring lines may be divided into two wiring lines, such as an aggregate of an information signal and a power supply line and a timing signal, or two wiring lines, such as an information line and an aggregate of a power supply line and a timing signal line.

In this case, in the modification for capturing still images, since the timing signal line is not necessary, it is not necessary to worry about the thickness of the wiring line.

In the modification for performing both still image capture and dynamic imaging, it is necessary to transmit and receive the timing signal, in addition to transmitting and receiving information required for still image capture and power supply. However, it is possible to easily modify the conventional system by dividing the wiring lines into two or more wiring lines and preventing an increase in the thickness of the wiring lines.

Example 8: Joining Before Wiring Lines are Connected

Joining of Wiring Lines

In some cases, the imaging apparatus3wirelessly transmits and receives signals and is used without a wiring line. Therefore, the imaging apparatus3is configured such that wiring lines for the transmission of information and the timing signal and for power supply can be attached and detached by, for example, a connector.

However, if a plurality of wiring lines are connected to the connector, the handling of the wiring lines becomes complicated. As a result, for example, the following problem occurs: a necessary wiring line is disconnected from the connector due to contact with other wiring lines and the transmission of signals is hindered, which makes it difficult to perform intended imaging.

In a case where the wiring lines to be connected are divided into an information line, a power supply line, a timing signal line, and combinations thereof, for example, as illustrated inFIG. 24, at least two or mores of the wiring lines may be joined using a joint8such that the number of wiring lines is less than the number of types of signals that are transmitted and received and the wiring lines may be connected to the imaging apparatus3.

In this case, the number of wiring lines is reduced and the handling of the wiring lines is simplified. Therefore, it is possible to reduce the risk that the intended imaging will not be performed, for example, the wiring lines will be disconnected.

The wiring lines extending from the additional apparatus6or6A to the imaging apparatus3may be divided into wiring lines required for still image capture and wiring lines required for dynamic imaging in addition to still image capture.

An example of the wiring line required for dynamic imaging in addition to still image capture is a wiring line for transmitting the timing signal.

In this case, the wiring line required for still image capture before modification can be used without any change. In a case where dynamic imaging is performed, it is possible to easily change the conventional apparatus that can capture only still images to an apparatus that can perform dynamic imaging only by adding the wiring lines required for dynamic imaging in addition to the existing wiring lines required for still image capture before modification.

Example 9: Acquisition of Information from Radiography Apparatus Through Additional Apparatus

Connection of Imaging Apparatus Through Additional Apparatus

Since the imaging apparatus control console42according to the above-described embodiments is connected to the communication network N, it can be connected to another imaging apparatus3(not illustrated) wirelessly or in a wired manner through the communication network.

The imaging apparatus3needs to be connected to the additional controller61or61A in order to perform the dynamic imaging described in the first and second embodiments.

In addition, the imaging apparatus control console42may be configured to perform information communication for dynamic imaging with the imaging apparatus3through the additional controller61or61A.

In this case, the imaging apparatus control console42acquires information related to, for example, the type of the imaging apparatus3from the connected imaging apparatus3through the additional controller61or61A.

This configuration enables the additional controller61or61A to reliably check whether the imaging apparatus3used for imaging can perform dynamic imaging.

Example 10: Display of Information Indicating Whether Dynamic Imaging is Available

Display of Imaging Apparatus Capable of Performing Dynamic Imaging

Since the imaging apparatus control console42according to the above-described embodiments is connected to the communication network N, it can be connected to another imaging apparatus3(not illustrated) wirelessly or in a wired manner through the communication network.

For example, as illustrated inFIG. 25, the system may be configured such that the radiographer displays information indicating whether the connected imaging apparatus3can capture only still images or can capture dynamic images in addition to still images on the display43of the imaging apparatus control console42.

Since information indicating whether the imaging apparatus can perform dynamic imaging is displayed on the imaging apparatus control console42, the radiographer can easily and reliably select the imaging apparatus that can perform dynamic imaging.

It is possible to prevent a situation in which the radiographer selects the imaging apparatus that is not capable of performing dynamic imaging by mistake and performs dynamic imaging without any change.

Example 11: Change in Selection Range of Resolution and Frame Rate

Selection of Dynamic Imaging Conditions

The radiographer needs to set an appropriate resolution or an appropriate frame rate to the imaging apparatus3used for imaging.

For example, as illustrated inFIG. 25, an available imaging apparatus3and the resolution or frame rate of the imaging apparatus3may be displayed.

In addition, the system may be configured such that the displayed resolution or frame rate can be selected.

In addition, the system may be configured as follows: in a case where the imaging apparatus3that corresponds to only still image capture is connected, the connected imaging apparatus3is displayed as an available imaging apparatus3and, for example, the condition setting regions R1and R2of an unavailable imaging apparatus3are grayed out such that the unavailable imaging apparatus3is not selectable as illustrated inFIG. 26; even in a case where the unavailable imaging apparatus3is selected, the setting of the unavailable imaging apparatus3is not permitted; or imaging is not permitted.

Further, the system may be configured such that, in addition to the resolution and the frame rate, for example, information indicating whether a binning process can be performed, an image transmission method, and the exposure time are displayed. In addition, the system may be configured such that one of the items can be selected.

Example 12: Switching Between Still Image Capture and Dynamic Imaging

Switching Between Still Image Capture and Dynamic Imaging

The radiographer selects one of still image capture and dynamic imaging at the right time according to the situation. Therefore, the radiography system needs to have a configuration capable of switching between still image capture and dynamic imaging.

For example, a method can be used which switches a control method between still image capture and dynamic imaging Specifically, in a case where still image capture is selected, the control of the additional controller61or61A is switched such that still image capture is performed. In a case where dynamic imaging is selected, the control of the additional controller61or61A is switched such that dynamic imaging is performed.

The system may be configured such that whether still image capture is currently selected or dynamic imaging is currently selected as illustrated inFIG. 26. In addition, the system may be configured such that the display is switched.

For example, if still image capture is selected, it is possible to display that still image capture is selected by graying out the condition setting region R1of dynamic imaging on the display43, as illustrated inFIG. 26.

In a case where the selected imaging apparatus3is the imaging apparatus3corresponding to dynamic imaging and the grayed-out condition setting region R1of dynamic imaging is selected, the imaging method is switched to dynamic imaging. In addition, the graying-out of the condition setting region R1is removed and the still image capture condition setting region R2is grayed out to display that dynamic imaging is selected, which is not illustrated.

The condition setting regions R1and R2can be selected by, for example, moving a pointer displayed on the screen to the condition setting region R1or R2of the desired imaging with the mouse and clicking the condition setting region with the mouse. Alternatively, in a case where the display43is a touch panel screen, the system may be configured such that the radiographer touches the condition setting region R1or R2of the desired imaging to select the condition setting region.

At that time, the system may be configured as follows: the imaging conditions of each of still image capture and dynamic imaging are stored; and, in a case where still image capture or dynamic imaging is selected, the imaging conditions of the selected imaging are automatically set. In addition, the imaging conditions of each of still image capture and dynamic imaging may be values that have been preset according to the imaging technique or may be values that have been changed and input by the radiographer.

In this configuration, for example, if the radiographer sets the imaging conditions of still image capture and selects dynamic imaging, the imaging conditions of dynamic imaging are displayed and set. The system may be configured such that, if the radiographer selects still image capture again, the imaging conditions of still image capture before dynamic imaging is selected are set and displayed.

In addition, in the setting of dynamic imaging, the maximum number of images to be captured may be set to one to switch to the control of still image capture.

In this configuration, even if there is one radiography system, it is possible to perform both still image capture and dynamic imaging according to the radiographer's selection.

Example 13: Reset by Pressing Irradiation Instruction Switch to First Stage

Start Timing of Reset Operation

The reset operation consumes power. Therefore, if the reset operation is repeated after the imaging sequence starts, power consumption increases. In particular, in a case where the imaging apparatus3is driven by a built-in battery, a dead battery problem occurs.

Therefore, for example, the reset operation (reading operation) may start after the irradiation preparation signal is turned on as illustrated inFIG. 27.

The system may be configured as follows. The timing signal is output before the irradiation preparation signal is transmitted and the reading instruction signal different from the timing signal is transmitted to the imaging apparatus3. If the imaging apparatus3receives the reading instruction signal, it performs the reading operation in response to the timing signal, which is not illustrated.

This configuration makes it possible to prevent an increase in the power consumption of the imaging apparatus3.

Example 14: Start of Dynamic Imaging Period after Stop of Reset

Imaging Start Timing

The reset operation of the imaging apparatus3is performed by scanning each of the pixels of the light receivers arranged in a matrix on the surface of a built-in substrate. Therefore, if imaging starts during the reset operation, some of the light receivers have completed the reset operation, but the remaining light receivers receive radiation in a state in which the reset operation has not been completed. As a result, in some cases, there is a difference in density distribution between a portion in which the reset operation has been completed and a portion in which the reset operation has not been completed in the radiographic image.

Therefore, it is preferable to start imaging from a state in which the reset operation is uniformly performed on all of the light receivers of the imaging apparatus3.

Specifically, the imaging apparatus3is configured to have a function of transmitting the irradiation start signal to the additional apparatus6or6A at the timing when the scanning of all of the pixels of the light receivers is completed after the reset operation starts.

Then, the additional apparatus6or6A receives the irradiation start signal at the timing when the reset operation is uniformly performed, turns on the imaging start signal which is an interlock, and repeatedly transmits the irradiation permission signal to the radiation controller11or11A.

According to this configuration, it is possible to reliably prevent a situation in which imaging is performed in a state in which the reset operation is not uniformly performed for the light receivers and there is a difference in density distribution between a portion in which the reset operation has been completed and a portion in which the reset operation has not been completed in the radiographic image.

Example 15: Determination of Whether Imaging Apparatus is in Irradiation State on Basis of Difference in Timing Signal

Signals when Radiation is not Emitted/when Radiation is Emitted

It is difficult for the imaging apparatus3to determine whether the reading operation is performed as the reset operation (while radiation is not emitted) or as imaging (while radiation is emitted) on the basis of only the timing signal. As a result, it is difficult to determine whether to store the read image as the captured image.

For this reason, the timing signal for the reset operation may be different from the timing signal for imaging.

Specifically, for example, there is a method which changes the pulse widths of the timing signal for the reset operation and the timing signal for imaging as illustrated inFIG. 28. Even in a case where the pulse width of the signal is changed, the reset operation or imaging can be performed at the exact timing if the reset operation or imaging is performed in accordance with the start of the reading operation and the rise of the pulse signal.

This configuration makes it possible for the imaging apparatus3to determine whether the reading operation is performed as the reset operation or as imaging on the basis of the timing signal. Therefore, it is possible to reliably eliminate the risk that, even though the timing signal is received during the emission of radiation, the reading operation to be performed will be erroneously determined to be the reset operation and the read captured image will be discarded.

Example 16: Input of Standby Time after Irradiation Preparation Signal is Received

Standby Time

In some cases, the interval between the pressing of the irradiation instruction switch5to the first stage (the output of the irradiation preparation signal) and the pressing of the irradiation instruction switch5to the second stage (the output of the irradiation instruction signal) is short depending on the radiographer. Further, in some cases, the signals output from the irradiation instruction switch5are not divided into the irradiation preparation signal and the irradiation instruction signal and the irradiation preparation signal and the irradiation instruction signal are input as the same signal, depending on the apparatus configuration. In this case, there is a possibility that dynamic imaging will start while imaging preparations, such as the rotation of the rotating anode, the warm-up of the imaging apparatus3by the reset operation of the imaging apparatus3, and image uniformization, are insufficient.

This may not cause any problem in a case where one still image is captured. However, in the case of dynamic imaging, for example, the obtained dynamic image may be analyzed using a difference in signal value between a plurality of images captured at different imaging times and the frame may be changed with a change in the state of the imaging apparatus3during dynamic imaging, which causes a problem.

Therefore, a timer may be provided in the additional apparatus6or6A and the timer may start to measure time in a case where the irradiation preparation signal is received. In a case where a predetermined standby time does not elapse from the start of the timer, the irradiation permission signal may not be output even though the irradiation instruction signal is input.

This configuration makes it possible to sufficiently perform, for example, the reset operation of the imaging apparatus3for the standby time. Since a change in the temperature of the imaging apparatus3after a warm-up is sufficiently performed is small, it is possible to prevent a change of the frame due to a change in the state of the imaging apparatus3during the dynamic imaging.

Example 17: Setting of Standby Time of Additional Apparatus to be Longer than Standby Time of Radiation Controller

Setting of Standby Time

Some radiation controllers11and11A have a function that does not transmit the irradiation signal until a predetermined standby time elapses in a case where the interval between the reception time of the irradiation preparation signal and the reception time of the irradiation instruction signal is short.

In a case where the system100or200is formed by the above-mentioned radiation controller11or11A and the additional apparatus6or6A having the function described in Example 16, the standby time set in the additional apparatus6or6A may be longer than the standby time of the radiation controller11or11A.

This configuration makes it possible to set the standby time considering the standby time required for the imaging apparatus3and the standby time required for the emission of radiation.

The standby time set in the radiation controller11or11A may be zero and the necessary standby time may be delayed by the additional apparatus6or6A.

In a case where the standby time set in the radiation controller11or11A, only the delay of radiation is considered. However, the above-mentioned configuration makes it possible to set the standby time in the additional controller61or61A, considering the standby time required for the imaging apparatus3and the standby time required for the emission of radiation.

Example 18: Standby Time is Set in Only Capture of First Image

Timing of Standby Time

In dynamic imaging, the standby time is required when the apparatus starts up. The standby time is required for only the capture of a first image and it is not necessary to set the standby time for the capture of the second and subsequent images.

Therefore, the system may be configured such that the standby time is set for only the capture of the first image and is not set for the capture of the second and subsequent images.

This configuration makes it possible to set the standby time required for only the capture of the first image in the imaging apparatus3and the emission of radiation.

Example 19: End of Imaging at Set Maximum Number of Captured Images

Stop of Imaging at Designated Number of Captured Images

There is a problem that the subject is unnecessarily exposed to radiation in a case where the radiographer continues to input an instruction to emit radiation (presses the irradiation instruction switch5to the second stage) and imaging is performed such that the number of captured images is greater than a predetermined maximum value.

Therefore, the system may be configured such that at least one of the additional controller61or61A, the imaging apparatus3, and the radiation controller11or11A has a function of counting the number of captured images.

In addition, the system may be configured such that at least one (which may be the same as or different from the component having the count function) of the additional controller61or61A, the imaging apparatus3, and the radiation controller11or11A has a function which compares the counted number of captured images with a predetermined maximum value and transmits information indicating that the counted number of captured images has reached the maximum value to at least one of the additional controller61or61A, the imaging apparatus3, and the radiation controller11or11A (including a case where the information is transmitted in the same controller) if the counted number of captured images reaches the maximum value.

The additional controller61or61A is configured to have a function that turns off the imaging permission signal and stops the output of the irradiation permission signal if it has received information indicating that the number of captured images has reached the maximum value.

It is preferable that the reading instruction or the timing signal for reading is further output for the capture of at least one image after the number of captured images reaches the maximum value. The reason is that, in a case where the number of times radiation is emitted is counted, it is necessary to read the image obtained by the last emission of radiation and to store the read image. In a case where the completion of reading is counted, this function is not necessary.

According to this configuration, since imaging ends reliably after the capture of the required number of images is completed, it is possible to prevent the subject from being unnecessarily exposed to radiation.

Example 20: Imaging is Continued after Irradiation Instruction, Number of Captured Images, and Presence of Failure are Checked

End of Imaging

For example, in a case where the instruction to emit radiation is interrupted, a case where the capture of a predetermined maximum number of images has been completed, or a case where a defect occurs in the apparatuses forming the radiography system or the control state of them, if imaging is continued, there is a problem that imaging is continued in a state which is not intended by the radiographer and the subject is unnecessarily exposed to radiation.

Therefore, the system may be configured to monitor at least one of whether the instruction to emit radiation is continuously issued (the pressing of the irradiation instruction switch5to the second stage is continued), whether the number of captured images is equal to or less than a predetermined maximum value, and whether a defect occurs in the apparatuses or the control state and to perform at least one of a process of interrupting imaging, a process of transmitting information indicating that there is a problem, and a process of displaying the information indicating that there is a problem if it is determined that there is a problem.

For example, this monitoring operation may be performed using control for changing the sequence state illustrated inFIG. 21.

A monitoring sequence different from this control may be simultaneously operated to perform the monitoring. In this case, since a double check is possible, it is possible to more reliably detect the occurrence of a problem.

This configuration makes it possible to prevent the subject from being unnecessarily exposed to radiation due to imaging performed in a state which is not intended by the radiographer.

The above-mentioned monitoring operation may be performed before the irradiation permission signal is transmitted first or before each irradiation permission signal that is repeatedly transmitted is transmitted.

In this case, it is possible to perform the above-mentioned determination in a state immediately before the irradiation permission signal for permitting the emission of radiation is transmitted. Therefore, it is possible to prevent radiation from being emitted (imaging from being performed) in a state that is not intended by the radiographer.

The invention is not limited to, for example, the above-described embodiments and may be appropriately changed without departing from the scope and spirit of the invention.

For example, it is possible to modify a radiation generation apparatus which has already been introduced into a medical institution and can perform only one radiation emission operation in response to one radiation emission instruction with the technique described in the invention such that the radiation generation apparatus can perform dynamic imaging.

Alternatively, the technique described in the invention may be combined with a radiation generation apparatus which can perform only one radiation emission operation in response to one radiation emission instruction to easily construct a new system that can perform dynamic imaging.

Commonalization of Low-Frame-Rate and High-Frame-Rate Imaging Operations

In a case where the operation of the imaging device3varies depending on the set imaging frame rate, if dynamic imaging is performed, there is a problem that a captured image obtained after the lapse of a predetermined time from the start of imaging is different in high-frame-rate imaging and low-frame-rate imaging.

For example, the number of frames captured until a predetermined time elapses from the start of imaging is different between a case where imaging is performed at a high frame rate and a case where imaging is performed at a low frame rate. Therefore, there is a problem that, for example, a change in the temperature of the imaging apparatus3associated with the imaging operation is different in high-frame-rate imaging and low-frame-rate imaging, which results in a difference in image quality between images.

This causes the following problem. For example, in a case where a change in the size of a region of interest, such as a tumor, is observed in detail on the basis of the images captured by high-frame-rate imaging immediately after surgery and the postoperative course is checked on the basis of the images captured by low-frame-rate imaging in order to reduce an exposure doze, if the images are changed due to a difference between the imaging modes, there is a problem that it is difficult to compare the postoperative course with that immediately after surgery.

In order to solve the above-mentioned problems, the imaging frame rate set in the imaging apparatus3may not be changed in a case where imaging is performed while the irradiation frame rate is changed. That is, even in a case the radiation emission period of the generation apparatus increases, the imaging apparatus3repeats the imaging operation with the same period. At that time, in a case where imaging is performed in the low-frame-rate mode, unexposed frames are extracted from the captured frames and a dynamic image formed by the extracted unexposed frames is generated.

In this configuration, since the influence of a temperature rise after the lapse of a predetermined time from the start of imaging is the same, it is possible to acquire images with the same quality at the same temperature even at different irradiation frame rates.

Change in Period for which Radiation can be Emitted

The imaging apparatus3sequentially reads an exposed image generated at the timing when radiation is emitted from the pixels at the end of the radiation detector32to acquire an image. If a part of the emission of radiation is performed while charge is sequentially read from the pixels at the end of the radiation detector32, a part of the radiographic image generated by the read operation may become a part of the image of the next frame. Therefore, the radiation emission time is limited to the period for which the reading operation of the imaging apparatus3is not performed.

However, since a radiation emission window that is the period for which radiation can be emitted is shorter in imaging with a high imaging frame rate, it is difficult to complete the emission of radiation within the radiation emission window. In particular, in the emission of pulsed radiation, there is a wave tail in which the emission of radiation remains in the second half of the pulse and it is difficult to put the wave tail into the radiation emission window.

In order to solve the problems, for example, the length of the radiation emission window may be changed according to whether to perform the thinning-out emission of radiation as illustrated inFIGS. 29A and 29B. In particular, in a case where the thinning-out emission of radiation is performed, the radiation emission window may be longer than that in a case where the thinning-out emission of radiation is not performed, as illustrated inFIG. 29B.

In this case, since there is enough time from the rising to the falling of pulsed radiation, it is easy to put the wave tail of radiation into the radiation emission window.

In thinning-out irradiation, even if the wave tail is not put into the radiation emission window, it is removed by the reading of the next thinned-output image. Therefore, even if the emission time of radiation is long, it is possible to remove the influence of the wave tail on the frame for capturing the next emission of radiation.

Change in Transmission Period

The dynamic imaging has a problem that, after an image is read, the transmission of the image may not be completed until the next accumulation.

In order to solve the problem, the image generated at the timing when no radiation is emitted may not be transmitted and may be stored in the imaging apparatus3or may be deleted from the imaging apparatus3.

For example, as illustrated inFIG. 30, the image generated at the timing when radiation is emitted is transmitted using at least a part of the accumulation and reading period of the timing when no radiation is emitted.

This configuration makes it possible to extend the transmission time of the image generated at the timing when radiation is emitted and to stably transmit the image.

In addition, it is possible to increase all of the frame rates.

Imaging Timing Control (1)

In a case where imaging is performed for a part of the irradiation instruction signal input period and the period from the time when the radiographer presses the irradiation instruction switch to the second stage to the time when imaging starts actually is long, there is a problem that it may be difficult to capture the dynamics desired by the radiographer.

In order to solve the problem, in a case where imaging is performed for a part of the irradiation instruction signal input period, for example, imaging (the emission of radiation/accumulation) may be performed at the timing when the first image can be captured after the radiographer instructs imaging, as illustrated inFIG. 31.

In this case, since imaging is performed as soon as possible after the radiographer instructs imaging, it is possible to start imaging at the timing when the radiographer wants to perform imaging and to reduce the risk that the radiographer will not take the desired images of the dynamics.

Imaging Timing Control (2)

Before the imaging apparatus3starts imaging, it needs to perform, for example, a reset operation or a warm-up. In some cases, it is desirable to capture an image at a timing as late as possible in order to obtain a stable image.

In order to solve the problem, in a case where imaging is performed for a part of the irradiation instruction signal input period, for example, imaging is not performed at the timing when the first image can be captured after the radiographer instructs imaging, but may be performed at other imaging timings, such as the timing after the second and subsequent images are captured, as illustrated inFIG. 32.

For example, in the case of imaging in which the generation apparatus emits radiation once whenever the imaging device3performs N imaging operations (N=2 inFIG. 32), imaging is performed at the N-th timing when imaging can be performed after the radiographer instructs imaging.

In this case, imaging is performed at a later timing after the radiographer instructs imaging. Therefore, the imaging apparatus3can sufficiently perform, for example, the reset operation or a warm-up and can start imaging in a stable state. As a result, it is possible to improve the quality of a captured image.

Standby Time Before Imaging Starts

Before starting imaging, the imaging apparatus3needs to perform, for example, a reset operation or a warm-up. In some cases, it is desirable to capture an image at a timing as late as possible in order to obtain a stable image.

In order to solve the problem, the delay time may be provided such that at least one of the imaging apparatus3, the additional controller61, the console4, and the radiation controller11A starts an imaging operation after the lapse of a predetermined time from the pressing of the irradiation instruction switch to the first or second stage.

In a case where imaging is performed in the dynamic imaging mode, the delay time may be longer than that in a case where imaging is performed in the still image capture mode.

The generation of an image may start after radiation is emitted several times for system stability in the initial stage of the imaging operation. In this case, the imaging apparatus3may be configured not to perform imaging in a case where radiation is emitted several times in the initial stage.

The emission of radiation may be suppressed by the radiation generator, the periphery thereof, or a collimator attached to the radiation generator2such that the subject is not irradiated with radiation in a case where radiation is emitted several times in the initial stage. As a method for suppressing the emission of radiation, for example, the following configuration may be used: a suppression plate that is less likely to transmit radiation is provided in the radiation generator2, the periphery thereof, or the collimator attached to the radiation generator2so as to be movable; and, in a case where radiation is emitted several times in the initial stage, the suppression plate is moved on a radiation emission axis to block radiation generated from the radiation generator2such that the emission of radiation to the surroundings is suppressed. After radiation is emitted several times in the initial stage, for example, the suppression plate is retracted from the irradiation axis. After the initial stage, it is possible to irradiate the subject with radiation to capture the image of the subject.

In this case, imaging is performed at a later timing after the radiographer instructs imaging. Therefore, the imaging apparatus3can sufficiently perform, for example, the reset operation or a warm-up and can start imaging in a stable state. As a result, it is possible to improve the quality of a captured image.

Method for Capturing Variation

There is an imaging method that focuses on a variation at a certain point of time of the dynamics, depending on the imaging technique. For example, in a case where an image of a blood flow is captured, it is not necessary to repeat imaging over a long period of time and it is preferable to obtain a plurality of (two or more) consecutive captured images at the moment when the image of a blood flow is desired to be captured.

However, in a case where it is difficult to acquire only the images before and after the necessary timing (imaging needs to always be repeated at the same timing), the subject is unnecessarily exposed to radiation.

In order to solve the problem, only necessary imaging may be performed at the timing when a variation is required or at the timing when only a plurality of consecutive captured images are required.

For example, as illustrated inFIG. 33, the imaging apparatus3is configured to repeatedly perform accumulation and reading with a predetermined period and the generation apparatus is configured to emit radiation only at a certain number of consecutive imaging timings.

According to this configuration, a plurality of consecutive captured images obtained by the emission of radiation are compared with each other to acquire a variation in the state of the subject for a predetermined period including the imaging time of a specific image.

For example, in a case where the image of a blood flow is captured, as illustrated inFIG. 33, a plurality of images are continuously captured at a specific timing and a change in the images is analyzed to check a blood flow at the imaging timing. In addition, it is possible to check the state of the blood flow at the imaging timing from the difference between a plurality of consecutive images.

InFIG. 33, two consecutive images are captured and a variation for the period from the capture of a first image to the capture of a second image is acquired. However, a variation for the period from the capture of a first image to the capture of a plurality of images may be acquired from three or more images captured at the right time. The calculation of a variation from three or more images makes it possible to reduce, for example, noise.

Further, unlike the case illustrated inFIG. 33, if the imaging apparatus emits radiation at all timings when it can accumulate charge, the subject is exposed to radiation that is twice as much as the necessary amount of radiation. However, as illustrated inFIG. 33, the emission of radiation is thinned out at an unnecessary timing, which makes it possible to reduce an exposure dose while obtaining necessary information.

Variable Frame Rate

In some cases, a necessary frame rate is changed during imaging, depending on the imaging technique.

However, it is difficult for the imaging apparatus3according to the related art to change the imaging frame rate during imaging Therefore, the imaging apparatus3according to the related art needs to perform accumulation and reading at a constant imaging frame rate and to emit radiation at a constant irradiation frame rate. As a result, the imaging apparatus3according to the related art emits radiation even in an unnecessary frame and the subject is unnecessarily exposed to radiation.

In order to solve the problem, for example, as illustrated inFIG. 34, imaging may be performed while the interval at which thinning-out is performed is changed at any imaging timing.

In this case, the imaging apparatus3may be configured to perform imaging at a constant imaging frame rate. Thereafter, only the image captured at the timing when radiation is emitted is selected to obtain an image captured at a changed frame rate.

This configuration makes it possible to use the imaging apparatus3according to the related art which is designed for a specific frame rate. The imaging apparatus3that performs imaging at a specific frame rate can be started up faster than a special imaging apparatus that can change the frame rate and can continue imaging stably.

In addition, it is possible to perform radiography only at a necessary frame rate by changing the timing when the emission of radiation is thinned out during imaging. It is possible to prevent the subject from being unnecessarily exposed to radiation.

Control by External Signal

The start timing of imaging and the timing when the frame rate is changed are determined by the dynamics of the subject or the operation of the imaging apparatus and the imaging system. For example, in an imaging technique that needs to change the start timing of imaging and the frame rate according to the operation state of the radiation generator, such as tomosynthesis which will described below, it is necessary to change the start timing of imaging and the timing when the frame rate is changed according to the operation of the apparatuses in the imaging system.

However, it is difficult for the radiographer to appropriately determine the start timing of imaging and the timing when the frame rate is changed while monitoring the dynamics of the subject and the operation of the imaging apparatus and the imaging system. For this reason, it is desirable to start imaging or change the frame rate using a measurement device that quantitatively measures dynamics or a detector that detects the start of a predetermined operation of the imaging apparatus3.

In order to solve the problem, the system may be configured such that imaging conditions, such as the start of imaging and a change in the frame rate, are changed by an external trigger.

For example, a heart rate monitor attached to the subject, an auto voice that instructs the operation of the subject, and a signal from the radiation control device1that controls the operation of the tube can be used as the external trigger.

This configuration makes it possible to start imaging or to change the frame rate at an appropriate timing, using a measurement device that quantitatively measures dynamics or a detector that detects the start of a predetermined operation of the imaging apparatus3.

Application Examples to Tomosynthesis and the Like

In an imaging method that performs imaging while moving the radiation generator2at a constant speed to generate a tomographic image, such as tomosynthesis, an image captured in a state in which the inclination of the radiation emission axis with respect to the axis orthogonal to the radiation incident surface3aof the imaging apparatus3is large has little influence on the tomographic image. Therefore, in imaging that generates the tomographic image, in some cases, it is desirable to reduce the imaging frame rate while the inclination of the radiation emission axis is large and to increase the imaging interval.

In contrast, in a case where the radiographer wants to obtain a precise tomographic image, the image captured in a state in which the inclination of the radiation emission axis with respect to the axis orthogonal to the radiation incident surface3aof the imaging apparatus3is large has a relatively large influence on the tomographic image. Therefore, contrary to the above-mentioned case, in some cases, it is desirable that the imaging interval is reduced while the inclination of the radiation emission axis is large and the imaging frame rate is reduced to increase the imaging interval while the inclination of the radiation emission axis is small.

However, the radiography control apparatus according to the related art performs imaging while emitting radiation at equal intervals. Therefore, there is a problem that the subject is unnecessarily exposed to radiation.

In order to solve the problem, a method that changes the irradiation frame rate according to the inclination of the radiation emission axis with respect to the radiation incident surface, that is, the thinning-out of radiation illustratedFIG. 34, may be performed.

For example, in a case where the imaging interval is reduced while the inclination of the radiation emission axis is large and is increased when the inclination is small, the radiation generator2performs control as follows. The radiation generator2increases the irradiation frame rate in a state in which it is located in a region (A) in which the inclination of the radiation emission axis is large among the regions (A) to (E) illustrated inFIG. 35(“without thinning-out (short imaging interval)” inFIG. 34) and reduces the irradiation frame rate in a state in which it is located in the region (B) in which the inclination of the radiation emission axis is less than that in the region (A) (“thinning-out1” inFIG. 34(for example, the emission of radiation is thinned out every other time)). In addition, the radiation generator2further reduces the irradiation frame rate in a state in which it is located in the region (C) in which the inclination of the radiation emission axis is less than that in the region (B) (“thinning-out2” inFIG. 34(for example, thinning-out is performed twice each time radiation is emitted)). Then, the radiation generator2increases the irradiation frame rate in the region (D) in which the inclination of the radiation emission axis is larger than that in the region (C) (“thinning-out1”) and further increases the irradiation frame rate in the region (E) in which the inclination of the radiation emission axis is larger than that in the region (D) (“without thinning-out (short imaging interval)”).

In some cases, it is desirable to change the imaging interval according to the imaging method such that the imaging interval is increased while the inclination of the radiation emission axis is large and is reduced while the inclination is small as described above. In this case, the radiation generator2changes the state to the same state as that in “thinning-out2” in a state in which it is located in the region (A) or (E) in which the inclination of the radiation emission axis is larger among the regions (A) to (E) illustrated inFIG. 35, increases the irradiation frame rate in a state in which it is located in the region (B) or (D) in which the inclination of the radiation emission axis is less than that in the region (A) or (E) (“thinning-out1” inFIG. 34), and further increases the irradiation frame rate in a state in which it is located in the region (C) in which the inclination of the radiation emission axis is less than that in the region (B) or (D) (“without thinning-out (short imaging interval)” inFIG. 34).

This configuration makes it possible to perform imaging with the amount of radiation required to generate a tomographic image, without unnecessarily irradiating the subject with radiation, and to reduce the exposure dose of the subject.

Application (1) of Addition Reading

There is a case where an image resolution equal to or greater than a predetermined value is required or there is a case where high-speed imaging is desired instead of low image resolution, depending on the imaging part and the imaging technique.

In order to solve the problem, the following configuration may be used. In a case where the imaging apparatus3reads a radiographic image, the imaging apparatus3changes the amount of addition reading (binning) in the pixels which are arranged in at least one of the vertical direction and the horizontal direction in the radiographic image to change the imaging frame rate and then performs imaging.

Specifically, in a case where an imaging part or an imaging technique is selected, the amount of binning, the imaging frame rate, and the degree of thinning-out N (the irradiation frame rate is set to 1/N of the imaging frame rate) are set according to the recommended amount of the selected imaging apparatus and then imaging is performed.

This configuration makes it possible to perform imaging at an appropriately resolution and an appropriate frame rate according to the imaging part and the imaging technique.

In addition, it is possible to increase the number of imaging techniques that can respond to various situations.

Application (2) of Addition Reading

As a method that adds the charge accumulated in each pixel of the imaging apparatus and performs reading, there are the following methods (a) and (b).

(a) Analog binning that adds and reads charge on a circuit

(b) Digital binning that individually reads charge on a circuit and then adds the read values

It is effective to perform addition reading using analog binning that can reduce the reading time, in order to increase the imaging frame rate. However, for example, in a case where the radiographer wants to switch the presence and absence of binning after image capture, or in a case where analog binning is performed and charge is added on the circuit before reading and is likely to exceed a convertible region of the A/D converter34cof the reader34of the imaging apparatus3, it may be preferable to use at least a part of the addition reading as digital binning.

In order to solve the problem, the imaging device3may use analog addition reading as addition reading for the pixels which are arranged in one of the vertical and horizontal directions of the radiographic image and may use digital addition reading as addition reading for the pixels arranged in the other direction.

In this case, it is possible to perform imaging at an appropriate resolution and an appropriate frame rate according to the imaging part and the imaging technique.

In particular, the amount or direction of the analog binning or the digital binning may be adjusted to increase the imaging frame rate of the imaging apparatus3and to increase combinations of the imaging frame rates.

For example, in a method, such as tomosynthesis, which performs imaging while moving the radiation generator2in predetermined direction, the resolution of the pixels arranged in a direction orthogonal to the movement direction of the radiation generator2in the imaging apparatus3may be more important than the resolution of the pixels arranged in the movement direction or, conversely, the resolution of the pixels arranged in the movement direction may be more important than the resolution of the pixels arranged in the direction orthogonal to the movement direction.

In this case, for example, the following imaging method can be used: for the pixels arranged in the movement direction of the imaging apparatus3, charge is added and read by analog binning to increase the frame rate; and, for the pixels arranged in the direction orthogonal to the movement direction of the imaging apparatus3, the amount of binning in digital binning is adjusted and vice versa.

Image Correction Method (1)

If the switching element32eprovided in each pixel of the imaging apparatus3is turned off, change can be accumulated in each pixel. If the switching element32eis turned on, the accumulated charge is output.

In a case where the imaging frame rate increases, there is a problem that the switching element32eis turned off before the charge accumulated in each pixel is output and the charge that has not been output remains as an afterimage in the next image.

In order to solve the problem, the unexposed image generated at the timing when no radiation is emitted may be used to correct the image in which an afterimage remains (reading efficiency correction).

Specifically, the reading efficiency correction is performed as represented by the following Expression (1):
Image(x,y) after reading efficiency correction={image(x,y) after gain correction−image(x,y) after gain correction before one frame×α(x,y)}/(1−a(x,y))  (1)

(where α indicates a correction coefficient (0<α<1) and (x, y) indicates coordinates in an image)

Specifically, the reading efficiency correction is disclosed on, for example, JP 2017-192605 A.

The reading efficiency correction requires the image before one frame. However, in this case, since the unexposed image is used for correction, it is possible to prevent an afterimage from remaining in the exposed image due to the operation of the switching element.

Image Correction Method (2)

In some cases, an afterimage remains even after the reading efficiency correction is performed for the unexposed image. In many cases, the afterimage is caused by a time lag (delay in the generation of charge or a lag component) in a case where the photodiode forming the radiation detection element32dgenerates charge.

In order to solve the problem, the lag component remaining in the next exposed image may be predicted on the basis of the time interval between the current unexposed image and the next exposed image and may be subtracted from the next exposed image.

The unexposed image includes a lag component generated at the timing when the exposed image of the previous frame is generated. Then, it is possible to calculate how much the lag component is included in the next exposed image from the attenuation characteristics.

The configuration makes it possible to prevent an afterimage from remaining in the exposed image due to the lag component.

Image Correction Method (3)

In some cases, a recursive filtering process represented by the following Expression (2) is performed for an image in order to suppress image graininess and line noise:
Image after processing of current frame=α×image after processing of previous frame+(1−α)×Image before processing of current frame  (2)

However, in a case where an image of a fast-moving subject is captured, there is a problem that the difference in the position of the subject between the previous exposed frame and the current exposed frame increases and an afterimage of the image before processing is included in the processed image.

In order to solve the problem, an unexposed image obtained immediately before the image to be corrected may be used for the recursive filtering process.

Line noise is noise that is not related to the amount of exposure and a predetermined amount of line noise is included in both the exposed image and the unexposed image. Therefore, the use of the unexposed image for the recursive filtering process makes it possible to average the line noise and to reduce the line noise.

In a case where the previous unexposed image is used, it is possible to suppress graininess and line noise and blurring is less likely to be noticeable even in the case of a fast-moving subject.

In a case where the subject moves pretty fast, blurring is likely to be noticeable even though the recursive filtering process using the unexposed image is performed. Therefore, it is preferable to switch whether to perform the recursive filtering process according to the thinning-out ratio or the movement of the subject.

Image Correction Method (4)

A steady-state value X of the image subjected to the recursive filtering process (in a case where radiation is emitted for every other frame) is represented by the following Expression (3):
X=1/(1+α)  (3)

In a case where the recursive filtering processing is performed for the dynamic image obtained by imaging without performing the thinning-out emission of radiation, for example, as can be seen fromFIG. 36, the steady-state value is reduced in the first few frames and then returns to the original value.

In contrast, in a case where the recursive filtering processing is performed for the dynamic image obtained by imaging using the thinning-out emission of radiation, a state in which the signal value of the processed image is low is repeated.

For example, in a case where the irradiation frame rate is ½ of the imaging frame rate (the emission of radiation is thinned-out for every other frame), the steady-state value of the image before processing is 1, and the correction coefficient cc is 0.2, the steady-state value X is 0.83.

In a case where the irradiation frame rate is ¼ of the imaging frame rate (the emission of radiation is thinned-out for three frames among four frames), the steady-state value of the image before processing is 1, and the correction coefficient α is 0.2, the steady-state value X is 0.8.

In order to solve the problem, the steady-state value of the thinned-out image may be divided by the value of X.

This configuration makes it possible to return the steady-state value to 1 even in a case where the steady-state value of the image after processing is reduced.

Although a specific calculation formula is omitted here, this example can also be applied to a dynamic image obtained by imaging in which radiation is emitted for every N frames (N−1 frames therebetween are unexposed frames).

Image Correction Method (5)

In some cases, a signal remains even after the reading efficiency correction is performed for the unexposed image and the lag component is subtracted. In many cases, this signal is caused by an increase in offset (offset drift) due to an increase in the temperature of the reader34.

In order to solve the problem, for example, the average value or the mode value of the amount of offset drift of the unexposed image before and after exposure may be subtracted from the exposure image to reduce an offset drift component.

This configuration makes it possible to prevent a signal resulting from the offset drift component from remaining in the exposure image.

In the above-mentioned examples, various types of image correction using the unexposed image have been described. However, in a case where the thinning-out emission of radiation is not performed, image processing is performed using, for example, the exposed image. That is, predetermined image correction is performed for the radiographic image captured in a state in which the imaging frame rate set in the imaging apparatus3is N times as high as the irradiation frame rate set in the generation apparatus Image correction different from the above-mentioned image correction is performed for the radiographic image captured in a state in which the imaging frame rate set in the imaging apparatus3is equal to the irradiation frame rate set in the generation apparatus.

The entire disclosure of Japanese Patent Applications No. 2018-188191 and No. 2018-188272, both filed on Oct. 3, 2018, is incorporated herein by reference in its entirety.