Radiographic image detector, method for operating radiographic image detector, program for operating radiographic image detector, and radiography system

An electronic cassette has a detection panel in which pixels accumulating charge corresponding to radiation emitted from a radiation source are arranged. A CPU of the electronic cassette transmits and receives a synchronizing signal to and from a radiation source control device. The CPU of the electronic cassette receives a setting notification signal indicating that irradiation conditions have been set from a console. After receiving the setting notification signal, the CPU of the electronic cassette directs the detection panel to start a charge reading operation. The CPU of the electronic cassette transmits an imaging preparation completion signal to the console after a predetermined number of charge reading operations are completed to notify that the predetermined number of charge reading operations have been completed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2021-192530, filed on Nov. 26, 2021. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND

1. Technical Field

The technology of the present disclosure relates to a radiographic image detector, a method for operating a radiographic image detector, a program for operating a radiographic image detector, and a radiography system.

2. Description of the Related Art

A radiographic image detector is known that has a detection panel in which pixels accumulating charge corresponding to radiation emitted from a radiation source are arranged. The detection panel is also called a flat panel detector (FPD). In this radiographic image detector, before charge corresponding to radiation is accumulated, a charge reading operation of reading unnecessary charge from the pixels is repeatedly performed a predetermined number of times. The unnecessary charge is dark charge generated regardless of whether or not radiation is emitted and residual charge (so-called residual image) caused by previous radiography.

In addition, in the radiographic image detector having the detection panel, it is necessary to synchronize the operation of the radiation source. As a synchronization method, there is a method in which a radiation source control device that controls the operation of a radiation source and a radiographic image detector are connected to each other and a synchronizing signal is transmitted and received between the radiation source control device and the radiographic image detector.

For example, JP2015-198939A discloses an aspect in which a synchronizing signal is transmitted and received between a radiation source control device and a radiographic image detector through an imaging control device. In JP2015-198939A, in a case in which an operator, such as a radiology technician, sets irradiation conditions of radiation (a tube voltage, a tube current, and an irradiation time) in the imaging control device, a detection panel starts a charge reading operation.

SUMMARY

In the technique disclosed in JP2015-198939A, in a case in which the operator instructs a radiation source to start the emission of the radiation before a predetermined number of charge reading operations are completed, the radiation source starts the emission of the radiation after waiting for the completion of the predetermined number of charge reading operations. Therefore, the operator may feel uncomfortable due to a discrepancy between the instruction of the operator and the operation of the radiation source.

One embodiment according to the technology of the present disclosure is to provide a radiographic image detector, a method for operating a radiographic image detector, a program for operating a radiographic image detector, and a radiography system that can reduce a concern that an operator will feel discomfort.

According to an aspect of the present disclosure, there is provided a radiographic image detector having a detection panel in which pixels accumulating charge corresponding to radiation emitted from a radiation source are arranged. The radiographic image detector comprises a processor. The processor transmits and receives a synchronizing signal for synchronizing an operation of the radiation source to and from a radiation source control device which controls the operation of the radiation source, receives, from an imaging control device in which imaging-related information related to radiography is set, a setting notification signal indicating that the imaging-related information has been set, directs the detection panel to start a charge reading operation of reading the charge from the pixel after the setting notification signal is received, and notifies, after a predetermined number of charge reading operations are completed, that the predetermined number of charge reading operations have been completed.

Preferably, the radiographic image detector has a rectangular shape in a plan view and has a long side with a length greater than 431.8 mm.

Preferably, the radiation source control device receives an irradiation start command signal for instructing the radiation source to start the emission of the radiation and transmits an irradiation start command reception signal indicating that the irradiation start command signal has been received as the synchronizing signal, and the processor directs the detection panel to continue the charge reading operation until the irradiation start command reception signal is received from the radiation source control device even after the predetermined number of charge reading operations are completed.

Preferably, after receiving the irradiation start command reception signal from the radiation source control device, the processor directs the detection panel to start an accumulation operation of accumulating the charge in the pixel and transmits an irradiation permission signal for permitting the emission of the radiation to the radiation source control device.

Preferably, the imaging-related information includes at least one of a time for which the detection panel performs an accumulation operation of accumulating the charge in the pixel, irradiation conditions of the radiation, an imaging part of a subject, an imaging posture of the subject, or an imaging direction of the subject.

Preferably, the radiographic image detector has a function of detecting a start of the emission of the radiation without depending on the synchronizing signal.

According to another aspect of the present disclosure, there is provided a method for operating a radiographic image detector having a detection panel in which pixels accumulating charge corresponding to radiation emitted from a radiation source are arranged. The method comprises: transmitting and receiving a synchronizing signal for synchronizing an operation of the radiation source to and from a radiation source control device which controls the operation of the radiation source; receiving, from an imaging control device in which imaging-related information related to radiography is set, a setting notification signal indicating that the imaging-related information has been set; directing the detection panel to start a charge reading operation of reading the charge from the pixel after the setting notification signal is received; and notifying, after a predetermined number of charge reading operations are completed, that the predetermined number of charge reading operations have been completed.

According to yet another aspect of the present disclosure, there is provided a program for operating a radiographic image detector having a detection panel in which pixels accumulating charge corresponding to radiation emitted from a radiation source are arranged. The program causes a computer to execute a process comprising: transmitting and receiving a synchronizing signal for synchronizing an operation of the radiation source to and from a radiation source control device which controls the operation of the radiation source; receiving, from an imaging control device in which imaging-related information related to radiography is set, a setting notification signal indicating that the imaging-related information has been set; directing the detection panel to start a charge reading operation of reading the charge from the pixel after the setting notification signal is received; and notifying, after a predetermined number of charge reading operations are completed, that the predetermined number of charge reading operations have been completed.

According to still another aspect of the present disclosure, there is provided a radiography system comprising: a radiation source that emits radiation; a radiation source control device that controls an operation of the radiation source; a radiographic image detector that has a detection panel in which pixels accumulating charge corresponding to the radiation are arranged; and an imaging control device in which imaging-related information related to radiography is set. The radiographic image detector has a processor. The processor transmits and receives a synchronizing signal for synchronizing an operation of the radiation source to and from the radiation source control device, receives a setting notification signal indicating that the imaging-related information has been set from the imaging control device, directs the detection panel to start a charge reading operation of reading the charge from the pixel after the setting notification signal is received, and notifies, after a predetermined number of charge reading operations are completed, that the predetermined number of charge reading operations have been completed.

According to the technology of the present disclosure, it is possible to provide a radiographic image detector, a method for operating a radiographic image detector, a program for operating a radiographic image detector, and a radiography system that can reduce a concern that an operator will feel discomfort.

DETAILED DESCRIPTION

First Embodiment

For example, as illustrated inFIG.1, a radiography system2is a system that performs radiography on a subject H using radiation R, such as X-rays or γ-rays, and is composed of a radiography apparatus10and a radiation generation device11. The radiography apparatus10has an electronic cassette12, a console13, and a signal relay device14. The radiation generation device11has a radiation source15, a radiation source control device16, and an irradiation switch17.

The electronic cassette12is a portable radiographic image detector that outputs a radiographic image40(seeFIG.2) corresponding to the radiation R transmitted through the subject H. The electronic cassette12is connected to the console13and the signal relay device14wirelessly or in a wired manner such that it can communicate with the console13and the signal relay device14. The electronic cassette12is accommodated in, for example, a holder19of an upright imaging stand18and is then used. In addition, the electronic cassette12can be removed from the holder19, stood up against the subject H or inserted under the subject H lying on a bed in a hospital room, and then used. Further, a decubitus imaging table may be provided instead of or in addition to the upright imaging stand18. Furthermore, the electronic cassette12is an example of a “radiographic image detector” according to the technology of the present disclosure.

The console13is, for example, a desktop personal computer and has a display20that displays various screens and an input device21that includes a keyboard, a mouse, and the like and receives operation instructions from an operator of the radiography system2. The console13transmits various signals to the electronic cassette12. In addition, the console13receives the radiographic image40from the electronic cassette12. The console13displays the radiographic image40on the display20. The console13is an example of an “imaging control device” according to the technology of the present disclosure. In addition, the console13may be a notebook personal computer or a tablet terminal.

The signal relay device14relays a synchronizing signal60(seeFIG.13) that is transmitted and received between the electronic cassette12and the radiation source control device16. The signal relay device14performs the following process in a case in which the radiography apparatus10and the radiation generation device11are manufactured by different manufacturers and the electronic cassette12and the radiation source control device16are not compatible with each other. That is, the signal relay device14converts the synchronizing signal60from the electronic cassette12into a synchronizing signal60suitable for the radiation source control device16and then transmits the synchronizing signal60to the radiation source control device16. Further, the signal relay device14converts the synchronizing signal60from the radiation source control device16into a synchronizing signal60suitable for the electronic cassette12and then transmits the synchronizing signal60to the electronic cassette12. Furthermore, in a case in which the electronic cassette12and the radiation source control device16are compatible with each other, the signal relay device14does not convert the synchronizing signal60, and the synchronizing signal60from a transmission source flows to a reception destination without any change. Alternatively, in a case in which the electronic cassette12and the radiation source control device16are compatible with each other, the signal relay device14may not be provided.

The radiation source15has a radiation tube22, an irradiation field limiter23, and a speaker24. The radiation tube22is provided with, for example, a filament, a target, and a grid electrode (none of which are illustrated). A voltage is applied between the filament, which is a cathode, and the target, which is an anode. The voltage applied between the filament and the target is called a tube voltage. The filament emits thermoelectrons corresponding to the applied tube voltage to the target. The target emits the radiation R by the collision of the thermoelectrons from the filament. The grid electrode is disposed between the filament and the target. The grid electrode changes the flow rate of the thermoelectrons from the filament to the target according to the applied voltage. The flow rate of the thermoelectrons from the filament to the target is called a tube current.

The irradiation field limiter23is also called a collimator and limits an irradiation field of the radiation R emitted from the radiation tube22. For example, the irradiation field limiter23has a configuration in which four shielding plates made of lead or the like that shields the radiation R are disposed on each side of a quadrangle and a quadrangular emission opening for transmitting the radiation R is formed in a central portion. The irradiation field limiter23changes the position of each shielding plate to change the size of the emission opening, thereby changing the irradiation field of the radiation R. Immediately before the radiation R is emitted, the speaker24emits a beep sound59(seeFIG.9) for notifying the subject H that the radiation R is about to be emitted.

The radiation source15and the irradiation switch17are connected to the radiation source control device16. The radiation source control device16controls the operation of the radiation source15in response to various command signals from the irradiation switch17. The irradiation switch17is operated in a case in which the operator instructs the radiation source15to start the emission of the radiation R. The irradiation switch17is a two-stage push type having a first switch25and a second switch26.

For example, as illustrated inFIG.2, the console13comprises a storage30, a memory31, a central processing unit (CPU)32, and a communication interface (I/F)33in addition to the display20and the input device21. The display20, the input device21, the storage30, the memory31, the CPU32, and the communication I/F33are connected to each other through a bus line (not illustrated).

The storage30is a hard disk drive that is provided in the computer constituting the console13or is connected to the computer through a cable or a network. The storage30stores, for example, a control program, such as an operating system, various application programs, and various kinds of data associated with these programs. In addition, a solid state drive may be used instead of the hard disk drive.

The memory31is a work memory used by the CPU32to perform processes. The CPU32loads the program stored in the storage30to the memory31and performs a process corresponding to the program. Therefore, the CPU32controls the overall operation of each unit of the computer. In addition, the memory31may be provided in the CPU32. The communication I/F33controls the transmission of various kinds of information to the electronic cassette12or an external device such as a radiology information system (RIS)34.

The CPU32receives an imaging order35from the RIS34through the communication I/F33. For example, subject identification data (ID) for identifying the subject H and an imaging procedure instruction from a doctor of a clinical department that has issued the imaging order35are registered in the imaging order35. The CPU32displays the imaging order35on the display20according to the operation of the operator using the input device21. The operator checks the content of the imaging order35through the display20.

The CPU32displays a plurality of types of imaging menus36on the display20to be selectable. For example, as illustrated inFIG.3, the imaging menu36defines an imaging procedure in which the imaging part of the subject H, the imaging posture of the subject H, and the imaging direction of the subject H, such as “a chest, a standing posture, and a back”, form one set. Examples of the imaging part include the head, the neck, the abdomen, the waist, the shoulder, the elbow, the hand, the knee, the ankle in addition to the chest. Examples of the imaging posture include a decubitus posture and a sitting posture in addition to the standing posture. Examples of the imaging direction include the front and the side in addition to the back. The operator operates the input device21to select one imaging menu36that is matched with the imaging procedure designated by the imaging order35from the plurality of types of imaging menus36. Then, the CPU32receives the imaging menu36. The CPU32reads irradiation conditions37(seeFIG.4) corresponding to the received imaging menu36from an irradiation condition table38stored in the storage30. The CPU32displays the read irradiation conditions37on the display20. The irradiation conditions37corresponding to various types of imaging menus36are registered in the irradiation condition table38. For example, as illustrated inFIG.4, the irradiation conditions37are a set of the tube voltage and the tube current applied to the radiation tube22and the irradiation time of the radiation R. Instead of the tube current and the irradiation time, a tube current-irradiation time product may be used as the irradiation condition37. The irradiation conditions37are an example of “imaging-related information” according to the technology of the present disclosure.

In a case in which the imaging menu36is selected by the operator and the irradiation conditions37corresponding to the imaging menu36are set, the CPU32transmits a setting notification signal39indicating that the irradiation conditions37have been set to the electronic cassette12through the communication I/F33. For example, as illustrated inFIG.5, the setting notification signal39includes a time (hereinafter, referred to as an accumulation time) for which a light detection substrate71of a detection panel68(seeFIG.10) performs an accumulation operation which will be described below. The accumulation time is the time obtained by adding the time when the synchronizing signal60(seeFIG.13) is transmitted and received between the electronic cassette12and the radiation source control device16to the irradiation time of the irradiation condition37. Further, in addition to or instead of the accumulation time, at least one of the irradiation time, the tube voltage, or the tube current may be included in the setting notification signal39.

The CPU32receives the radiographic image40from the electronic cassette12through the communication I/F33. After performing various types of image processing on the radiographic image40, the CPU32displays the radiographic image40on the display20such that the operator views the radiographic image40.

For example, as illustrated inFIG.6, the radiation source control device16comprises a touch panel display45, a memory46, a control unit47, a tube voltage generator48, and a communication I/F49. The touch panel display45displays various screens and receives operation instructions from the operator. Similarly to the irradiation condition table38for the console13, a plurality of types of representative irradiation conditions37are registered in the memory46. The control unit47reads the plurality of types of irradiation conditions37from the memory46and displays the read plurality types of irradiation conditions37on the touch panel display45so as to be selectable. The operator operates the touch panel display45to select irradiation conditions37matched with the irradiation conditions37set in the console13among the plurality of types of irradiation conditions37. The control unit47sets the irradiation conditions37selected by the operator in the tube voltage generator48. The tube voltage generator48boosts an input voltage with a transformer to generate a tube voltage. The tube voltage generated by the tube voltage generator48is supplied to the radiation tube22through a voltage cable (not illustrated). In addition, the irradiation conditions37can be corrected by operating the touch panel display45before being set in the tube voltage generator48.

The control unit47transmits and receives the synchronizing signal60to and from the signal relay device14and thus the electronic cassette12through the communication I/F49. Further, the control unit47adjusts the degree of opening of the emission opening of the irradiation field limiter23. Furthermore, the control unit47controls the operation of the speaker24.

For example, as illustrated inFIG.7, in a case in which the operator turns on the first switch25, the irradiation switch17outputs a warm-up command signal55to the radiation source control device16. In a case in which the radiation source control device16receives the warm-up command signal55, the radiation source control device16(control unit47) performs a warm-up operation. The warm-up operation is an operation that preheats the filament and starts the rotation of the target. The radiation source control device16completes the warm-up operation in a case in which the filament reaches a predetermined temperature and the rotation speed of the target reaches a predetermined value. In addition, in a case in which the warm-up operation is completed, the beep sound59may be output from the speaker24to notify the operator that the warm-up operation has been completed.

For example, as illustrated inFIG.8, in a case in which the operator turns on the second switch26in a state in which the warm-up operation is completed, the irradiation switch17outputs an irradiation start command signal56instructing the start of the emission of the radiation R to the radiation source control device16. In a case in which the irradiation start command signal56is received, the radiation source control device16(control unit47) transmits an irradiation start command reception signal57indicating that the irradiation start command signal56has been received as the synchronizing signal60to the signal relay device14and thus the electronic cassette12.

For example, as illustrated inFIG.9, after receiving the irradiation start command reception signal57from the radiation source control device16, the electronic cassette12transmits an irradiation permission signal58for permitting the emission of the radiation R as the synchronizing signal60to the signal relay device14and thus the radiation source control device16. In a case in which the irradiation permission signal58is received, the radiation source control device16(control unit47) performs an irradiation operation indicated by the following procedure. First, the beep sound59is output from the speaker24. Then, the tube voltage generator48applies the tube voltage to the radiation tube22to generate the radiation R from the radiation tube22. At this time, a timer is operated to measure the time elapsed since the start of the generation of the radiation R. In a case in which the elapsed time reaches the irradiation time set in the irradiation conditions37, the application of the tube voltage is stopped, and the emission of the radiation R is ended.

For example, as illustrated inFIG.10, the electronic cassette12has a housing65with a flat box shape (a rectangular shape in a plan view). The housing65is made of conductive metal or resin. Therefore, the housing65also functions as an electromagnetic shield that prevents electromagnetic noise from entering the electronic cassette12and electromagnetic noise from being emitted from the electronic cassette12to the outside. A radiation transmission plate66having a rectangular plate shape which is slightly smaller than the housing65is attached to a front surface of the housing65on which the radiation R is incident. The radiation transmission plate66is made of, for example, a carbon material that is lightweight and has high rigidity and high radiation transparency.

An image output unit67is accommodated in the housing65. The image output unit67has the detection panel68and a circuit unit69. The detection panel68is composed of a scintillator70and the light detection substrate71which have substantially the same size as the radiation transmission plate66.

The scintillator70and the light detection substrate71are stacked in the order of the scintillator70and the light detection substrate71as viewed from the front side of the housing65on which the radiation R is incident. The scintillator70has a phosphor, such as CsI:Tl (thallium-activated cesium iodide) or GOS (Gd2O2S:Tb, terbium-activated gadolinium oxysulfide), converts the incident radiation R into visible light, and emits the visible light. The light detection substrate71has a configuration in which a plurality of pixels80(seeFIG.12) are arranged on a single thin film transistor (TFT) active matrix substrate, detects the visible light emitted from the scintillator70, and converts the visible light into an electric signal. The circuit unit69controls the operation of the pixels80of the light detection substrate71and generates the radiographic image40on the basis of the electric signal output from the light detection substrate71.

Further, the scintillator70and the light detection substrate71may be stacked in the order of the light detection substrate71and the scintillator70as viewed from the front side. Furthermore, the detection panel68may not be an indirect conversion type in which the scintillator70converts the radiation R into visible light and the light detection substrate71converts the visible light into an electric signal as in this example, but may be a direct conversion type that directly converts the radiation R into an electric signal.

In addition, a battery and an antenna are provided in the housing65, which is not illustrated. In a case in which wireless communication with, for example, the console13is performed by the antenna, the electronic cassette12can be driven by power from the battery and used wirelessly.

For example, as illustrated inFIG.11, a length SSL of a short side75of the housing65is, for example, 431.8 mm (≈17 inches). In contrast, a length LSL of a long side76of the housing65is, for example, 787.4 mm (≈31 inches). That is, the length LSL of the long side76is larger than 431.8 mm.

For example, as illustrated inFIG.12, the light detection substrate71has a configuration in which a plurality of pixels80are arranged in a two-dimensional matrix along X and Y directions which are orthogonal to each other. The X direction is a direction along the short side75and the Y direction is a direction along the long side76. In a case in which the number of pixels80arranged in the X direction is M and the number of pixels80arranged in the Y direction is N, each of M and N is an integer equal to or greater than 2. For example, M is 2000, and N is 3800. As is well known, the pixel80includes a photoelectric conversion unit81that generates charge (electron-hole pair) by the incidence of visible light and accumulates the charge and a TFT82as a switching element that controls the accumulation of the charge in the photoelectric conversion unit81and the reading of the charge from the photoelectric conversion unit81. The photoelectric conversion unit81includes, for example, a p-intrinsic-n (PIN) semiconductor layer, an upper electrode that is disposed above the semiconductor layer, and a lower electrode that is disposed below the semiconductor layer. A bias voltage is applied to the upper electrode. The lower electrode is connected to a drain electrode of the TFT82.

N scanning lines83that extend in parallel to the X direction and M signal lines84that extend in parallel to the Y direction are formed on the light detection substrate71. The N scanning lines83and the M signal lines84are wired in a grid shape. The pixel80is disposed in an intersection portion of the scanning line83and the signal line84. Specifically, in the pixel80, a gate electrode of the TFT82is connected to the scanning line83, and a source electrode of the TFT82is connected to the signal line84. Each scanning line83is commonly connected to M pixels80corresponding to one row along the X direction. Each signal line84is commonly connected to N pixels80corresponding to one column along the Y direction.

The circuit unit69has a gate driver85and a signal processing circuit86. The scanning lines83are connected to the gate driver85. The signal lines84are connected to the signal processing circuit86.

The gate driver85outputs a gate pulse to the scanning line83. The gate pulse is uniformly applied to the gate electrodes of all of the TFTs82of the M pixels80connected to the scanning line83. The TFT82is turned on in a case in which the voltage of the gate pulse is at a high level and is turned off in a case in which the voltage is at a low level. The time when the TFT82is turned on is defined by the width of the gate pulse. The charge accumulated in the photoelectric conversion unit81of the pixel80is input to the signal processing circuit86through the signal line84in a case in which the TFT82is turned on.

The signal processing circuit86has a charge amplifier90, an amplifier91, a correlated double sampling (CDS) circuit (abbreviated to CDS inFIG.12)92, a multiplexer93, and an analog/digital (A/D) converter94. One charge amplifier90, one amplifier91, and one CDS circuit92are provided for each signal line84. That is, M charge amplifiers90, M amplifiers91, and M CDS circuits92are provided.

The charge amplifier90integrates the charge input from the signal line84, converts the integrated value into an analog voltage signal, and outputs the analog voltage signal. The charge amplifier90is composed of an operational amplifier95, a capacitor96, and a reset switch97. The capacitor96and the reset switch97are connected in parallel between an input terminal and an output terminal of the operational amplifier95. The signal line84is connected to the input terminal of the operational amplifier95, and the amplifier91is connected to the output terminal of the operational amplifier95.

The output terminal of the operational amplifier95in each column is connected to an input side of the multiplexer93through the amplifier91and the CDS circuit92. The A/D converter94is connected to an output side of the multiplexer93. The amplifier91amplifies the analog voltage signal with a predetermined amplification factor. The CDS circuit92performs well-known correlated double sampling on the amplified analog voltage signal to remove a reset noise component by the reset switch97. In addition, the amplifier91is not limited to the configuration in which it is provided between the charge amplifier90and the CDS circuit92. For example, the amplifier91may be provided between the CDS circuit92and the A/D converter94, such as between the CDS circuit92and the multiplexer93.

The multiplexer93sequentially selects the connected M CDS circuits92to sequentially input the analog voltage signals subjected to the correlated double sampling to the A/D converter94. The A/D converter94sequentially converts the analog voltage signals input from the multiplexer93into digital signals and outputs the converted digital signals to a CPU100. The CPU100has an image memory (not illustrated) corresponding to one frame and stores a digital signal based on the charge accumulated in the photoelectric conversion unit81of each pixel80as the radiographic image40.

The CPU100controls the overall operation of the electronic cassette12. The CPU100controls the operation of the circuit unit69such that the light detection substrate71performs any one of the accumulation operation, the image detection operation, or the charge reading operation and the radiographic image40is output from the light detection substrate71. The CPU100is an example of a “processor” according to the technology of the present disclosure.

The accumulation operation is an operation that accumulates charge corresponding to the incident amount of radiation R in the photoelectric conversion unit81. In the accumulation operation, the CPU100does not input the gate pulse from the gate driver85to the TFTs82and turns off the TFTs82. Charge is accumulated in the photoelectric conversion unit81while the TFT82is in the off state.

The image detection operation is an operation that detects a digital signal based on the charge accumulated in the photoelectric conversion unit81in the accumulation operation as the radiographic image40. In the image detection operation, the CPU100directs the gate driver85to sequentially generate the gate pulses for turning on the TFTs82in the same row at once, thereby sequentially activating the scanning lines83row by row. In a case in which the TFTs82corresponding to one row are turned on, the charge accumulated in each of the photoelectric conversion units81of the pixels80corresponding to one row is input to the signal processing circuit86through the signal line84in each column. As described above, in the signal processing circuit86, the charge corresponding to one row is converted into an analog voltage signal by the charge amplifier90, and the analog voltage signal is converted into a digital signal by the A/D converter94.

In a case in which the charge amplifiers90output the analog voltage signals corresponding to one row, the CPU100turns on the reset switches97. This resets the charge accumulated in the capacitors96. After resetting the charge amplifiers90in this manner, the CPU100directs the gate driver85to output the gate pulse to the scanning line83in the next row such that the charge accumulated in the photoelectric conversion units81of the pixels80in the next row is input to the signal processing circuit86. The CPU100directs the light detection substrate71to repeat this operation, thereby converting the charge accumulated in the photoelectric conversion units81of the pixels80in all rows into digital signals.

The charge reading operation is an operation that reads unnecessary charge, such as dark charge generated regardless of whether the radiation R is emitted and residual charge caused by the previous radiography, from the photoelectric conversion unit81. In this example, the CPU100performs the charge reading operation using a sequential reading method which reads unnecessary charge row by row as in the above-mentioned image detection operation. Specifically, the CPU100directs the gate driver85to sequentially generate the gate pulse in each scanning line83row by row, thereby sequentially turning on the TFTs82row by row. Then, unnecessary charge accumulated in the photoelectric conversion unit81is input to the signal processing circuit86through the signal line84.

The CPU100turns on the reset switch97of the charge amplifier90in synchronization with the generation of the gate pulse to reset the unnecessary charge. As described above, in the charge reading operation, unlike the image detection operation, the conversion of charge into an analog voltage signal and the conversion of the analog voltage signal into a digital signal are not performed. Of course, in order to acquire an offset correction image or a residual image correction image which will be described below, the conversion of charge into an analog voltage signal and the conversion of the analog voltage signal into a digital signal may be performed in the charge reading operation as in the image detection operation.

The charge reading operation from the start of the reading of unnecessary charge in the first row, which is an initial row, to the end of the reading of unnecessary charge in an N-th row, which is the last row, is counted as one operation.

The CPU100performs various correction processes on the radiographic image40. The various correction processes include, for example, an offset correction process, a residual image correction process, a sensitivity correction process, and a defective pixel correction process. The offset correction process is a process that subtracts the offset correction image detected in a state in which the radiation R is not emitted from the radiographic image40in units of pixels. The CPU100performs the offset correction process to remove fixed pattern noise caused by, for example, dark charge from the radiographic image40. The residual image correction process is a process that subtracts a residual image correction image corresponding to the residual charge caused by the previous radiography from the radiographic image40in units of pixels. The sensitivity correction process is a process that corrects, for example, a variation in the sensitivity of the photoelectric conversion unit81in each pixel80and a variation in the output characteristics of the signal processing circuit86on the basis of sensitivity correction data. The defective pixel correction process is a process that linearly interpolates the value of a defective pixel with the values of surrounding normal pixels80on the basis of the information of the defective pixel having an abnormal value, which is generated during shipping or a regular inspection. In addition, the various correction processes may be performed in the console13.

A storage101, a memory102and a communication I/F103are connected to the CPU100. The CPU100, the storage101, the memory102, and the communication I/F103are connected to each other through a bus line (not illustrated). The CPU100, the storage101, and the memory102are an example of a “computer” according to the technology of the present disclosure.

An operation program104is stored in the storage101. The CPU100loads the operation program104to the memory102and performs a process corresponding to the operation program104. Therefore, the CPU100controls the overall operation of each unit of the electronic cassette12. In addition, the memory102may be provided in the CPU100. The operation program104is an example of a “program for operating a radiographic image detector” according to the technology of the present disclosure.

The communication I/F103is connected to the console13and the signal relay device14wirelessly or in a wired manner such that it can communicate with the console13and the signal relay device14. The communication I/F103transmits and receives the setting notification signal39and the radiographic image40to and from console13. In addition, the communication I/F103transmits and receives the synchronizing signal60to and from signal relay device14.

For example, as illustrated inFIG.13, in a case in which the operation program104is started, the CPU100functions as a setting notification signal receiving unit110, an operation control unit111, a notification unit112, a synchronizing signal transmitting and receiving unit113, a correction processing unit114, and an image transmission unit115.

The setting notification signal receiving unit110receives the setting notification signal39from the console13. The setting notification signal receiving unit110outputs, to operation control unit111, information indicating that the setting notification signal39has been received and the accumulation time included in the setting notification signal39.

The operation control unit111controls the operation of the circuit unit69. In a case in which the information indicating that the setting notification signal39has been received is input from the setting notification signal receiving unit110, the operation control unit111operates the circuit unit69to return the light detection substrate71and the like from a standby state to a normal use state. The standby state is a state in which power is supplied only to the minimum functions, such as the function of communicating with the console13through the communication I/F103, and other functions are suspended. On the other hand, the normal use state is a state in which power is supplied to all of the functions and the light detection substrate71can detect the radiographic image40.

After returning the light detection substrate71and the like to the normal use state, the operation control unit111directs the light detection substrate71to perform the charge reading operation a predetermined number of times. A sufficient number of times (for example, 10 times) to remove unnecessary charge from the photoelectric conversion unit81is set as the predetermined number of times. After completing the predetermined number of charge reading operations, the operation control unit111outputs, to the notification unit112, information indicating that the predetermined number of charge reading operations have been completed.

In a case in which the information indicating that the predetermined number of charge reading operations has been completed is received from the operation control unit111, the notification unit112transmits an imaging preparation completion signal120to the console13. The imaging preparation completion signal120is a signal indicating that the predetermined number of charge reading operations have been completed and the electronic cassette12is ready for radiography.

The synchronizing signal transmitting and receiving unit113transmits and receives the synchronizing signal60to and from the signal relay device14and thus the radiation source control device16. Specifically, the synchronizing signal transmitting and receiving unit113receives the irradiation start command reception signal57from the radiation source control device16. The synchronizing signal transmitting and receiving unit113outputs, to the operation control unit111, that the irradiation start command reception signal57has been received.

The operation control unit111directs the light detection substrate71to continue the charge reading operation even after the predetermined number of charge reading operations have been completed. The operation control unit111directs the light detection substrate71to start the accumulation operation in a case in which the information indicating that the irradiation start command reception signal57has been received is input from the synchronizing signal transmitting and receiving unit113. The operation control unit111outputs, to the synchronizing signal transmitting and receiving unit113, information indicating that the light detection substrate71has been directed to start the accumulation operation. The synchronizing signal transmitting and receiving unit113transmits the irradiation permission signal58to the radiation source control device16in a case in which the information indicating that the light detection substrate71has been directed to start the accumulation operation is input from the operation control unit111.

The operation control unit111measures the time elapsed since the start of the accumulation operation. In a case in which the elapsed time reaches the accumulation time included in the setting notification signal39, the operation control unit111directs the light detection substrate71to perform the image detection operation. Then, the radiographic image40is output from the signal processing circuit86.

The correction processing unit114performs various correction processes including the above-described offset correction process on the radiographic image40from the signal processing circuit86. The correction processing unit114outputs the radiographic image40subjected to the correction processes to the image transmission unit115. The image transmission unit115transmits the radiographic image40to the console13.

In a case in which the imaging preparation completion signal120is received from the electronic cassette12, the CPU32of the console13displays, for example, a notification screen130illustrated inFIG.14on the display20. A message131indicating that the predetermined number of charge reading operations have been completed and the electronic cassette12is ready for radiography is displayed on the notification screen130. An OK button132is operated to make the notification screen130disappear.

FIG.15is a timing chart illustrating a series of operations of the console13, the radiation source control device16, and the electronic cassette12(light detection substrate71) in one radiography operation. First, in a case in which the operator sets the irradiation conditions37in the console13, the console13transmits the setting notification signal39to the electronic cassette12. In a case in which the electronic cassette12receives the setting notification signal39, it returns from the standby state to the normal use state. Then, the light detection substrate71of the electronic cassette12starts the charge reading operation.

In a case in which the predetermined number of charge reading operations have been completed, the electronic cassette12transmits the imaging preparation completion signal120to the console13. The console13displays the notification screen130on the display20in a case in which the imaging preparation completion signal120is received.

In a case in which the operator turns on the first switch25of the irradiation switch17, the radiation source control device16performs the warm-up operation. Then, in a case in which the operator turns on the second switch26of the irradiation switch17, the radiation source control device16transmits the irradiation start command reception signal57to the electronic cassette12. The light detection substrate71continues the charge reading operation. The light detection substrate71starts the accumulation operation in a case in which the irradiation start command reception signal57is received. In addition, the electronic cassette12transmits the irradiation permission signal58to the radiation source control device16. The radiation source control device16performs the irradiation operation in a case in which the irradiation permission signal58is received.

In a case in which the time elapsed since the start of the accumulation operation reaches the accumulation time included in the setting notification signal39, the light detection substrate71performs the image detection operation and outputs the radiographic image40. The electronic cassette12transmits the radiographic image40to the console13. Then, the electronic cassette12returns to the standby state. The console13displays the radiographic image40on the display20.

Next, the operation of the above-mentioned configuration will be described with reference to a flowchart illustrated inFIG.16. In a case in which the power of the electronic cassette12is turned on, the operation program104is started. Then, the CPU100of the electronic cassette12functions as the setting notification signal receiving unit110, the operation control unit111, the notification unit112, the synchronizing signal transmitting and receiving unit113, the correction processing unit114, and the image transmission unit115as illustrated inFIG.13.

First, the operator sets the irradiation conditions37in the console13. Then, the setting notification signal39is transmitted from the console13to the electronic cassette12.

In the electronic cassette12, the setting notification signal receiving unit110receives the setting notification signal39from the console13(YES in Step ST100). Information indicating that the setting notification signal39has been received and the accumulation time included in the setting notification signal39are output from the setting notification signal receiving unit110to the operation control unit111.

The operation control unit111returns the light detection substrate71and the like from the standby state to the normal use state (Step ST110). Then, the light detection substrate71performs the charge reading operation under the control of the operation control unit111(Step ST120). The charge reading operation is continued a predetermined number of times.

After the predetermined number of charge reading operations are completed (YES in Step ST130), the operation control unit111outputs, to the notification unit112, information indicating that the predetermined number of charge reading operations have been completed. Then, the imaging preparation completion signal120is transmitted from the notification unit112to the console13(Step ST140). Then, the charge reading operation is continued.

The notification screen130is displayed on the display20in the console13that has received the imaging preparation completion signal120. In this way, the operator is notified that the predetermined number of charge reading operations have been completed and that the electronic cassette12is ready for radiography.

After setting the irradiation conditions37, the operator adjusts the positions of the electronic cassette12, the radiation source15, and the subject H to prepare for radiography. Then, the operator turns on the first switch25of the irradiation switch17to direct the radiation source control device16to perform the warm-up operation. Then, the operator turns on the second switch26of the irradiation switch17. Then, the irradiation start command reception signal57is transmitted from the radiation source control device16to the electronic cassette12.

In the electronic cassette12, the synchronizing signal transmitting and receiving unit113receives the irradiation start command reception signal57from the radiation source control device16(YES in Step ST160). Then, information indicating that the irradiation start command reception signal57has been received is output from the synchronizing signal transmitting and receiving unit113to the operation control unit111.

The light detection substrate71performs the accumulation operation under the control of the operation control unit111. Further, the synchronizing signal transmitting and receiving unit113transmits the irradiation permission signal58to the radiation source control device16(Step ST170).

The radiation source control device16that has received the irradiation permission signal58performs the irradiation operation to irradiate the subject H with the radiation R. The scintillator70converts the radiation R transmitted through the subject H into visible light. The visible light is incident on the light detection substrate71. Since the accumulation operation is performed in the light detection substrate71, charge corresponding to the incident visible light is accumulated in the photoelectric conversion unit81of each pixel80.

The operation control unit111measures the time elapsed since the start of the accumulation operation. In a case in which the elapsed time reaches the accumulation time (YES in Step ST180), the image detection operation is performed in the light detection substrate71under the control of the operation control unit111(Step ST190). Therefore, the radiographic image40is output from the signal processing circuit86.

The correction processing unit114performs various correction processes on the radiographic image40, and the image transmission unit115transmits the radiographic image40to the console13(Step ST200). Then, the operation control unit111returns the light detection substrate71and the like to the standby state (Step ST210), and the process is ended. In addition, even in a case in which a predetermined time has elapsed since the reception of the setting notification signal39by the setting notification signal receiving unit110after the transmission of the imaging preparation completion signal120(YES in Step ST150), the operation control unit111determines that a time-out has occurred, and the light detection substrate71and the like are returned to the standby state (Step ST210). Then, the process is ended.

The console13performs various types of image processing on the radiographic image40from the electronic cassette12. Then, the radiographic image40is displayed on the display20.

As described above, the electronic cassette12has the detection panel68(light detection substrate71) in which the pixels80accumulating charge corresponding to the radiation R emitted from the radiation source15are arranged. The CPU100of the electronic cassette12functions as the setting notification signal receiving unit110, the operation control unit111, the notification unit112, and the synchronizing signal transmitting and receiving unit113. The synchronizing signal transmitting and receiving unit113transmits and receives the synchronizing signal60to and from the radiation source control device16. The setting notification signal receiving unit110receives the setting notification signal39indicating that the irradiation conditions37have been set from the console13. After receiving the setting notification signal39, the operation control unit111directs the light detection substrate71to start the charge reading operation. The notification unit112transmits the imaging preparation completion signal120to the console13after the predetermined number of charge reading operations are completed to notify that the predetermined number of charge reading operations have been completed. Therefore, the operator is prevented from giving an instruction to start the emission of the radiation R before the predetermined number of charge reading operations are completed. As a result, the possibility that the emission of the radiation R will be started after the predetermined number of charge reading operations are completed is reduced. Therefore, it is possible to reduce the concern that the operator will feel uncomfortable.

The following is considered: the light detection substrate71performs the charge reading operation not after the irradiation conditions37are set and the setting notification signal39is received, but in a case in which the operator turns on the first switch25of the irradiation switch17, as in a comparative example illustrated inFIG.17. In a case in which the operator turns on the second switch26of the irradiation switch17, a situation in which the predetermined number of charge reading operations have not yet been completed occurs. Then, a waiting time WT until the predetermined number of charge reading operations are completed, the irradiation permission signal58is transmitted and received between the electronic cassette12and the radiation source control device16, and the radiation source control device16starts the irradiation operation (start the emission of the radiation R) after the second switch26is turned on is required. There is a concern that the waiting time WT will make the operator feel uncomfortable. In the technology of the present disclosure, in a case in which the operator turns on the second switch26, the predetermined number of charge reading operations have already been completed. Therefore, the waiting time WT does not occur.

As the time required for the predetermined number of charge reading operations becomes longer, the waiting time WT becomes longer. The time required for one charge reading operation becomes longer as the number of rows of pixels80becomes larger. Therefore, in the case of the electronic cassette12in which the length of the long side76is larger than 431.8 mm as in this example, the waiting time WT is longer than that in the case of the electronic cassette in which the length of the long side76is equal to or less than 431.8 mm. Therefore, according to the electronic cassette12in which the length of the long side76is larger than 431.8 mm, it is possible to further exhibit the effect of reducing the concern that the operator will feel uncomfortable. In addition, in a case in which the length of the long side76is 431.8 mm, the time required for the predetermined number of charge reading operations is, for example, about 1 second. However, in a case in which the length of the long side76is 787.4 mm as in this example, the time required for the predetermined number of charge reading operations is as long as, for example, about 2 seconds.

The radiation source control device16receives the irradiation start command signal56for instructing the radiation source15to start the emission of the radiation R and transmits the irradiation start command reception signal57indicating that the irradiation start command signal56has been received as the synchronizing signal60. The operation control unit111directs the light detection substrate71to continue the charge reading operation until the synchronizing signal transmitting and receiving unit113receives the irradiation start command reception signal57from the radiation source control device16even after the predetermined number of charge reading operations are completed. Therefore, it is possible to remove the unnecessary charge generated after the predetermined number of charge reading operations are completed.

The operation control unit111directs the light detection substrate71to start the accumulation operation after receiving the irradiation start command reception signal57from the radiation source control device16. The synchronizing signal transmitting and receiving unit113transmits the irradiation permission signal58permitting the emission of the radiation R to the radiation source control device16. Therefore, it is possible to synchronize the irradiation operation of the radiation source control device16with the accumulation operation of the light detection substrate71.

In this example, the imaging-related information is the irradiation conditions37of the radiation R. The timing when the irradiation conditions37are set is before an instruction to start the emission of the radiation R is input to the radiation source15. Therefore, in a case in which the irradiation conditions37are set and then the predetermined number of charge reading operations are started, the probability that the predetermined number of charge reading operations will have already been completed at the time when the radiation source15is instructed to start the emission of the radiation R is very high. Therefore, the chances of starting the emission of the radiation R after waiting for the completion of the predetermined number of charge reading operations are greatly reduced, and it is possible to further reduce the concern that the operator will feel discomfort.

Further, in addition to or instead of the irradiation conditions37given as an example, the imaging-related information may include at least one of the accumulation time, the imaging part of the subject H, the imaging posture of the subject H, or the imaging direction of the subject H.

Second Embodiment

For example, as illustrated inFIG.18, a plurality of radiation detection pixels80X are discretely provided on a light detection substrate140according to this embodiment. The radiation detection pixel80X has the same basic configuration as the pixel80in that it has a photoelectric conversion unit81and a TFT82, but is different from the pixel80in that a source electrode and a drain electrode of the TFT82are short-circuited. Therefore, charge generated in the photoelectric conversion unit81of the radiation detection pixel80X is always input to the signal processing circuit86through the signal line84regardless of the operating state of the TFT82.

The signal processing circuit86outputs a digital signal (hereinafter, referred to as a radiation detection signal141(seeFIG.19)) based on the charge generated in the photoelectric conversion unit81of the radiation detection pixel80X to a CPU142at a sample interval of, for example, microsecond order. The radiation detection signal141can be output to the CPU142even while the light detection substrate140is performing the charge reading operation or the accumulation operation. During the charge reading operation, the radiation detection signal141is output by accumulating charge in the capacitor96without turning on the reset switch97of the charge amplifier90in the column in which the radiation detection pixel80X is present. The level of the radiation detection signal141changes according to the irradiation dose of the radiation R per unit time. In a case in which the emission of the radiation R is started, the irradiation dose of the radiation R per unit time gradually increases. Therefore, the level of the radiation detection signal141also gradually increases.

An operation program143is stored in the storage101. The operation program143is an example of a “program for operating a radiographic image detector” according to the technology of the present disclosure. In a case in which the operation program143is started, the CPU142functions as a detection unit145in addition to each of the processing units110to115(only the operation control unit111is illustrated inFIG.19) according to the first embodiment as illustrated inFIG.19as an example.

The radiation detection signal141is input from the signal processing circuit86to the detection unit145. The detection unit145compares the level of the radiation detection signal141with a preset irradiation start detection threshold value. In a case in which the level of the radiation detection signal141is equal to or greater than the irradiation start detection threshold value, the detection unit145determines that the radiation source15has started the emission of the radiation R and detects the start of the emission of the radiation R. The detection unit145outputs, to the operation control unit111, information indicating that the start of the emission of the radiation R has been detected. The operation control unit111directs the light detection substrate140to start the accumulation operation in a case in which the information indicating that the start of the emission of the radiation R has been detected is input from the detection unit145. According to the radiation detection pixel80X and the detection unit145, the electronic cassette can synchronize the start of the emission of the radiation R with the start of the accumulation operation, without transmitting and receiving the synchronizing signal60to and from the radiation source control device. The radiation detection pixel80X and the detection unit145are an example of “a function of detecting the start of the emission of radiation without depending on a synchronizing signal” according to the technology of the present disclosure.

For example, as illustrated inFIG.20, in the electronic cassette according to this embodiment, as in the first embodiment, after the setting notification signal39indicating that the irradiation conditions37have been set is received, the light detection substrate140starts the predetermined number of charge reading operations. Further, after the predetermined number of charge reading operations are completed, the imaging preparation completion signal120indicating that the predetermined number of charge reading operations have been completed is transmitted to the console13. Furthermore, in a case in which the accumulation time included in the setting notification signal39has elapsed since the start of the accumulation operation, the light detection substrate140starts the image detection operation. The difference from the first embodiment is that, instead of transmitting and receiving the synchronizing signal60(the irradiation start command reception signal57and the irradiation permission signal58) to and from the radiation source control device, the detection unit145detects the start of the emission of the radiation R and the light detection substrate140starts the accumulation operation according to the detection of the start of the emission.

As described above, in the second embodiment, the electronic cassette has a function of detecting the start of the emission of the radiation R, without depending on the synchronizing signal60. Therefore, it is possible to respond to a radiation source control device that does not have a function of transmitting and receiving the synchronizing signal60. In addition, the following aspect is the same as that in the first embodiment: after the setting notification signal39indicating that the irradiation conditions37have been set is received, the light detection substrate140starts the predetermined number of charge reading operations; and, after the predetermined number of charge reading operations are completed, the imaging preparation completion signal120indicating that the predetermined number of charge reading operations have been completed is transmitted to the console13. Therefore, even in the second embodiment, it is possible to obtain the effect of reducing the concern that the operator will feel discomfort.

In addition, in a case in which the emission of the radiation R is ended, the level of the radiation detection signal141gradually decreases and finally becomes zero. Therefore, the detection unit145may detect not only the start of the emission of the radiation R but also the end of the emission. Specifically, the detection unit145compares the level of the radiation detection signal141with a preset irradiation end detection threshold value. In a case in which the level of the radiation detection signal141is less than the irradiation end detection threshold value, the detection unit145determines that the emission of the radiation R by the radiation source15has ended and detects the end of the emission of the radiation R. The detection unit145outputs, to the operation control unit111, information indicating that the end of the emission of the radiation R has been detected. The operation control unit111directs the light detection substrate140to perform the image detection operation in a case in which the information indicating that the end of the emission of the radiation R has been detected is input from the detection unit145. In this way, the electronic cassette can synchronize not only the start of the emission of the radiation R and the start of the accumulation operation but also the end of the emission of the radiation R and the end of the accumulation operation (the start of the image detection operation).

The radiation detection pixel80X may have a configuration in which only the photoelectric conversion unit81is provided, the TFT82is not provided, and the photoelectric conversion unit81is directly connected to the signal line84. In addition, the radiation detection pixel80X has exactly the same configuration as the pixel80without short-circuiting the source electrode and the drain electrode of the TFT82, and a dedicated gate driver may be provided for the radiation detection pixel80X such that charge can be read from the radiation detection pixel80X independently of the pixel80.

In the first embodiment, the notification screen130is displayed on the display20of the console13to notify the operator that the predetermined number of charge reading operations have been completed. However, the present disclosure is not limited thereto. An indicator, such as a light emitting diode (LED), may be provided in the housing65of the electronic cassette12, and the operator may be notified that the predetermined number of charge reading operations have been completed through the indicator. Further, the operator may be notified that the predetermined number of charge reading operations have been completed through the speaker24of the radiation source control device16. Alternatively, a warning light may be provided in the upright imaging stand18and turned on to notify the operator that the predetermined number of charge reading operations have been completed.

In the first embodiment, the electronic cassette12in which the length of the long side76is larger than 431.8 mm is given as an example. However, the present disclosure is not limited thereto. An electronic cassette in which the length of one side is less than 431.8 mm may be used.

In each of the above-described embodiments, the emission of the radiation R is ended on the basis of the irradiation time set in the irradiation conditions37. However, the present disclosure is not limited thereto. The emission of the radiation R may be ended by an auto exposure control (AEC) function. The AEC function is a function that detects the dose of the radiation R during the emission of the radiation R and stops the emission of the radiation R at the time when an integrated value of the detected dose (cumulative dose) reaches a preset target dose. In this case, in the electronic cassette, the detection panel starts the image detection operation in a case in which the cumulative dose of the radiation R reaches the target dose.

The electronic cassette is given as an example of the radiographic image detector. However, the present disclosure is not limited thereto. A radiographic image detector that is installed in the imaging table may also be used. Alternatively, a radiographic image detector that is fixed at a position facing the radiation source in a C-arm or the like may be used.

In each of the above-described embodiments, for example, the following various processors can be used as a hardware structure of processing units performing various processes, such as the setting notification signal receiving unit110, the operation control unit111, the notification unit112, the synchronizing signal transmitting and receiving unit113, the correction processing unit114, the image transmission unit115, and the detection unit145. The various processors include, for example, the CPUs100and142which are general-purpose processors executing software (operation programs104and143) to function as various processing units as described above, a programmable logic device (PLD), such as a field programmable gate array (FPGA), which is a processor whose circuit configuration can be changed after manufacture, and a dedicated electric circuit, such as an application specific integrated circuit (ASIC), which is a processor having a dedicated circuit configuration designed to perform a specific process.

One processing unit may be configured by one of the various processors or a combination of two or more processors of the same type or different types (for example, a combination of a plurality of ASICs and/or a combination of an ASIC and an FPGA). In addition, a plurality of processing units may be configured by one processor.

A first example of the configuration in which a plurality of processing units are configured by one processor is an aspect in which one processor is configured by a combination of one or more CPUs and software and functions as a plurality of processing units. A representative example of this aspect is a client computer or a server computer. A second example of the configuration is an aspect in which a processor that implements the functions of the entire system including a plurality of processing units using one integrated circuit (IC) chip is used. A representative example of this aspect is a system-on-chip (SoC). As such, various processing units are configured by using one or more of the various processors as a hardware structure.

Furthermore, specifically, an electric circuit (circuitry) obtained by combining circuit elements, such as semiconductor elements, can be used as the hardware structure of the various processors.

In the technology of the present disclosure, the above-described various embodiments and/or various modification examples may be combined with each other. In addition, the present disclosure is not limited to each of the above-described embodiments, and various configurations can be used without departing from the gist of the present disclosure. Furthermore, the technology of the present disclosure extends to a storage medium that non-temporarily stores a program, in addition to the program.

The above descriptions and illustrations are detailed descriptions of portions related to the technology of the present disclosure and are merely examples of the technology of the present disclosure. For example, the above description of the configurations, functions, operations, and effects is the description of examples of the configurations, functions, operations, and effects of portions according to the technology of the present disclosure. Therefore, unnecessary portions may be deleted or new elements may be added or replaced in the above descriptions and illustrations without departing from the gist of the technology of the present disclosure. In addition, in the content described and illustrated above, the description of, for example, common technical knowledge that does not need to be particularly described to enable the implementation of the technology of the present disclosure is omitted in order to avoid confusion and facilitate the understanding of portions related to the technology of the present disclosure.

In the specification, “A and/or B” is synonymous with “at least one of A or B”. That is, “A and/or B” means only A, only B, or a combination of A and B. Further, in the specification, the same concept as “A and/or B” is applied to a case in which the connection of three or more matters is expressed by “and/or”.

All of the documents, the patent applications, and the technical standards described in the specification are incorporated by reference herein to the same extent as each individual document, each patent application, and each technical standard are specifically and individually stated to be incorporated by reference.