WO2013125111A1

WO2013125111A1 - Radiographic imaging control device, radiographic imaging system, control method for radiographic imaging device, and control program for radiographic imaging

Info

Publication number: WO2013125111A1
Application number: PCT/JP2012/079825
Authority: WO
Inventors: 岩切　直人; 北野　浩一
Original assignee: 富士フイルム株式会社
Priority date: 2012-02-22
Filing date: 2012-11-16
Publication date: 2013-08-29

Abstract

A radiographic imaging control device comprising: a radiation detector that has an array of a plurality of pixels, each of which is configured to include a sensor unit that generates an electric charge in response to irradiated radiation and a switching element for reading the electric charge generated by the sensor unit; an amplification means for amplifying an electrical signal based on the electric charge read by the switching element from a corresponding pixel by a preset amplification factor, and in which a reset means for resetting the electric charge of an integrating capacitor for integrating the electric charge is provided corresponding to each pixel of the radiation detector; and a control means for controlling the switch means, so that the reset time set by the reset means is shorter than a preset time, if the electric charge generated by imaging using the radiation detector is expected to be lower than a predetermined value.

Description

Radiographic imaging control apparatus, radiographic imaging system, radiographic imaging apparatus control method, and radiographic imaging control program

The present invention relates to a radiographic imaging control device, a radiographic imaging system, a radiographic imaging device control method, and a radiographic imaging control program.

In recent years, radiation detectors such as FPD (Flat Panel Detector) that can arrange radiation sensitive layers on TFT (Thin Film Transistor) active matrix substrates and convert radiation dose into digital data (electrical signals) (referred to as “electronic cassettes”) In some cases, a radiation image capturing apparatus that captures a radiation image represented by the amount of irradiated radiation using this radiation detector has been put into practical use.

In such a radiation detector, electric charges corresponding to the radiation dose are accumulated and read out to perform signal processing. As an example of an apparatus for performing this signal processing, for example, a technique described in JP-A-2002-199292 is disclosed. Proposed.

In the technique described in Japanese Patent Application Laid-Open No. 2002-199292, a plurality of terminals connected to a plurality of signal sources, and a readout circuit unit that converts a signal input from the plurality of terminals into a serial signal and outputs the serial signal, In the signal transfer device, the readout circuit unit includes a first operational amplifier connected to each terminal and a second operational amplifier that receives an output of the first operational amplifier, and the first operational amplifier includes: An inverting input terminal connected to a corresponding terminal, an output terminal connected to an integral capacitor and a switch connected in parallel between the inverting input terminal, and a non-inverting input terminal to which a reference voltage is supplied Proposed signal processing devices have been proposed. The second operational amplifier includes a normal input terminal to which a reference voltage is supplied and an inverting input terminal that receives the output of the first operational amplifier. The second operational amplifier includes an inverting input terminal and an output terminal. It is described that a circuit for controlling an open / close time of the switch of the first operational amplifier and the reset switch of the second operational amplifier is provided by connecting an integration capacitor and a reset switch therebetween.

In the technique described in Japanese Patent Laid-Open No. 2002-199292, it is described that the reset time of the amplifier is controlled. However, since it is assumed that the remaining charge is completely reset, there is still room for improvement in order to further reduce the reset time and the imaging time.

The present invention has been made in consideration of the above facts, and aims to shorten the shooting time.

In order to achieve the above object, a radiographic imaging control apparatus according to the present invention includes a sensor unit that generates a charge corresponding to irradiated radiation and a switching element for reading out the charge generated by the sensor unit. A plurality of pixels arranged in correspondence with each of the pixels of the radiation detector, reset means for resetting the charge of the integrating capacitor for integrating the charge, and corresponding pixels When it is expected that the electric charge generated by the imaging using the radiation detector and the amplifying means for amplifying the electric signal due to the electric charge read by the switching element from a predetermined value is lower than a predetermined value, Control means for controlling the switch means so that the reset time by the reset means is shorter than a predetermined time; It is provided.

According to the radiographic imaging control device of the present invention, in the radiation detector, a plurality of pixels configured to include a sensor unit and a switching element are arranged, and charges corresponding to the irradiated radiation are generated in the sensor unit. The charge is read by the switching element.

The amplifying means is provided corresponding to each pixel of the radiation detector, and is provided with reset means for resetting the charge of the integrating capacitor for integrating the charge, and the charge read out from the corresponding pixel by the switching element. Is amplified at a predetermined amplification factor.

Then, the control means controls the switch means so that the reset time by the reset means is shorter than a predetermined time when the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value. Is done. That is, when photographing is performed when the charge generated by photographing using the radiation detector is expected to be lower than a predetermined value, the charge is less than when performing other photographing. Can be shortened, whereby the photographing time can be shortened. Therefore, since the imaging time can be shortened, the radiation dose of the subject is reduced, and the burden on the subject can be reduced.

The control means may control the switch means so that the reset time becomes shorter as the charge generated by the shooting is smaller, or in the case of moving image shooting, compared with still image shooting. The switch means may be controlled so that the reset time by the reset means is shortened, or in the case of positioning moving image shooting for adjusting at least one of the shooting position and shooting timing, the reset time is The switch means may be controlled so as to be shorter than a predetermined time, or the switch means may be controlled so that the reset time is shortened according to the type of continuous shooting. In the case of video continuous shooting that cuts out a still image from a moving image, the reset time is shorter than the shooting that is the target of the still image. As to the reset at a predetermined time without, it may control the reset means.

Further, the present invention may be a radiographic imaging system including the radiographic imaging control device described above and radiation irradiating means for irradiating the radiation detector via a subject.

On the other hand, the method for controlling a radiographic imaging apparatus of the present invention includes (a) a sensor unit that generates charges according to irradiated radiation and a switching element for reading out the charges generated by the sensor units. A plurality of pixels arranged corresponding to each pixel of the radiation detector, reset means for resetting the charge of the integrating capacitor for integrating the charge, and reading from the corresponding pixel by the switching element. The remaining charge before imaging is reset by the resetting means in the amplifying means for amplifying the electric signal generated by the charge at a predetermined amplification rate, and (b) the charge generated by imaging using the radiation detector is predetermined. If the value is expected to be lower than the value of (a), the reset time by the reset means in (a) is shorter than the predetermined time So as to, to control said switch means.

According to the method for controlling a radiographic imaging apparatus of the present invention, in (a), there is provided a reset means provided corresponding to each pixel of the radiation detector and resetting the charge of an integrating capacitor for integrating the charge. At the same time, the remaining charge before photographing is reset by the resetting means in the amplifying means for amplifying the electric signal based on the charge read out from the corresponding pixel by the switching element at a predetermined amplification factor.

In (b), when the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value, the reset time by the reset means in (a) is made shorter than a predetermined time. , Controlling the switch means. That is, when photographing is performed when the charge generated by photographing using the radiation detector is expected to be lower than a predetermined value, the charge is less than when performing other photographing. Can be shortened, and thus the photographing time can be shortened. By shortening this imaging time, the radiation dose of the subject is reduced, and the burden on the subject can be reduced.

In (b), the switch means may be controlled so that the reset time becomes shorter as the charge generated by the shooting is smaller, or compared with still image shooting in the case of moving image shooting. Then, the switch means may be controlled so that the reset time by the reset means is shortened, or in the case of positioning video shooting for adjusting at least one of the shooting position and the shooting timing, the reset time The switch means may be controlled so that the time is shorter than a predetermined time, or the switch means is controlled so that the reset time is shortened according to the type of continuous shooting. In the case of video continuous shooting that cuts out a still image from a moving image, the reset time for the shooting that is the target of the still image The without shortening to reset at a predetermined time, it may be controlled to the reset means.

On the other hand, the radiographic image capturing control program of the present invention includes (a) a pixel that includes a sensor unit that generates a charge corresponding to irradiated radiation and a switching element for reading out the charge generated by the sensor unit. Is provided corresponding to each pixel of the radiation detector arranged in plural, reset means for resetting the charge of the integration capacitor for integrating the charge is provided, and read out from the corresponding pixel by the switching element The remaining charge before imaging is reset by the resetting means in the amplifying means for amplifying the electric signal generated by the charge at a predetermined amplification factor, and (b) the charge generated by imaging using the radiation detector is a predetermined value. If it is expected to be lower, the reset time by the reset means in (a) is shorter than a predetermined time. So that, for controlling the switching means to execute the process to the computer.

According to the radiographic imaging control program of the present invention, in (a), there is provided reset means provided corresponding to each pixel of the radiation detector and resetting the charge of an integrating capacitor for integrating the charge. Then, the remaining charge before photographing is reset by the resetting means in the amplifying means for amplifying the electric signal based on the charge read out from the corresponding pixel by the switching element at a predetermined amplification factor.

In (b), when the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value, the reset time by the reset means in (a) is made shorter than a predetermined time. , Controlling the switch means. That is, when photographing is performed when the charge generated by photographing using the radiation detector is expected to be lower than a predetermined value, the charge is less than when performing other photographing. Can be shortened, and thus the photographing time can be shortened. Therefore, since the imaging time can be shortened, the radiation dose of the subject is reduced, and the burden on the subject can be reduced.

As described above, in the present invention, when the charge generated by imaging using a radiation detector is expected to be lower than a predetermined value, the imaging time is shortened by shortening the reset time from a predetermined time. And it has the outstanding effect that the burden on a test subject can be reduced.

It is a block diagram which shows the structure of the radiation information system which concerns on embodiment. It is a side view which shows an example of the arrangement | positioning state of each apparatus in the radiography room of the radiographic imaging system which concerns on embodiment. It is a cross-sectional schematic diagram which shows schematic structure of 4 pixel parts of the radiation detector which concerns on embodiment. It is a figure which shows the electrical constitution of the pixel part of the radiation detector which concerns on embodiment. It is a block diagram which shows schematic structure of the signal processing part of the radiation detector which concerns on embodiment. It is a figure which shows the equivalent circuit which paid its attention to 1 pixel part of the radiation detector which concerns on embodiment. It is a control block diagram of the imaging system according to the embodiment of the present invention. It is a figure which shows the output waveform accompanying the reading of the electric charge of a charge amplifier. It is a figure which shows the amplifier reset by the reset switch in a data read-out period, the reference sampling of a sample hold circuit, the signal sampling of a sample hold circuit, and the on-off timing of the gate of a thin-film transistor. It is the figure which expanded the data reading period for 1 line of FIG. 8A. It is the figure which shortened the amplifier reset time of FIG. 8B. It is a flowchart which shows the radiographic imaging preparation control routine which concerns on embodiment of this invention. It is a flowchart which shows the radiation irradiation control routine which concerns on embodiment of this invention. It is a flowchart which shows the image processing control routine which concerns on embodiment of this invention. It is a flowchart which shows the gradation signal taking-in process routine which concerns on embodiment of this invention.

FIG. 1 is a schematic configuration diagram of a radiation information system (hereinafter referred to as “RIS” (Radiology Information System)) 10 according to the present embodiment. The RIS 10 can shoot moving images in addition to still images. The definition of a moving image means that still images are displayed one after another at a high speed and recognized as a moving image. The still image is shot, converted into an electric signal, transmitted, and the still image is reproduced from the electric signal. This process is repeated at high speed. Accordingly, “frame advance”, in which the same area (part or all) is photographed a plurality of times within a predetermined time and continuously reproduced depending on the degree of “high speed”, is also included in the moving image. To do.

The RIS 10 is a system for managing information such as medical appointments and diagnosis records in the radiology department, and is a part of a hospital information system (hereinafter referred to as “HIS” (Hospital Information System)).

The RIS 10 includes a plurality of radiographic imaging systems installed individually in a plurality of imaging request terminal devices (hereinafter referred to as “terminal devices”) 12, a RIS server 14, and a radiographic room (or operating room) in a hospital. (Hereinafter referred to as “imaging system”) 16, which are connected to an in-hospital network 18 composed of a wired or wireless LAN (Local Area Network) or the like. The hospital network 18 is connected to an HIS server that manages the entire HIS. In addition, the imaging system 16 may be single or three or more facilities. In FIG. 1, the imaging system 16 is installed for each imaging room, but two or more imaging systems 16 are arranged in a single imaging room. May be.

The terminal device 12 is used by doctors and radiographers to input and view diagnostic information and facility reservations, and radiographic image capturing requests and imaging reservations are performed via the terminal device 12. Each terminal device 12 includes a personal computer having a display device, and is capable of mutual communication via the RIS server 14 and the hospital network 18.

On the other hand, the RIS server 14 receives an imaging request from each terminal device 12 and manages a radiographic imaging schedule in the imaging system 16, and includes a database 14A.

The database 14A was photographed in the past as attribute information (name, gender, date of birth, age, blood type, weight, patient ID (Identification), etc.), medical history, medical history of the patient as the subject. Information related to the patient such as a radiographic image, information related to the electronic cassette 20 used in the imaging system 16, such as an identification number (ID information), model, size, sensitivity, start date of use, number of times of use, etc. And an environment in which a radiographic image is taken using the electronic cassette 20, that is, an environment in which the electronic cassette 20 is used (for example, a radiographic room or an operating room).

In addition, medical-related data managed by medical institutions is stored almost permanently, and when necessary, a system (sometimes referred to as a “medical cloud”) that instantly retrieves data from the required location can be used outside the hospital. You may make it acquire the past personal information etc. of a patient (subject) from a server.

The imaging system 16 captures a radiographic image by an operation of a doctor or a radiographer according to an instruction from the RIS server 14. The imaging system 16 is a radiation generator that irradiates a subject with radiation X having a dose according to irradiation conditions from a radiation irradiation source 22A that irradiates radiation X under the control of a radiation irradiation control unit 22 (see FIG. 6). 24 and a radiation detector 26 (see FIG. 3A) that generates radiation by absorbing the radiation X that has passed through the region to be imaged of the subject and generates image information indicating a radiation image based on the amount of the generated charge. A built-in electronic cassette 20, a cradle 28 for charging a battery built in the electronic cassette 20, and a console 30 for controlling the electronic cassette 20 and the radiation generator 24 are provided.

The console 30 acquires various types of information included in the database 14A from the RIS server 14 and stores them in an HDD 88 (see FIG. 6) described later, and uses the information as necessary to use the electronic cassette 20 and the radiation generator 24. Control.

FIG. 2 shows an example of the arrangement state of each device in the radiation imaging room 32 of the imaging system 16 according to the present embodiment.

As shown in FIG. 2, in the radiation imaging room 32, there are a standing table 34 used when performing radiography in a standing position and a prone table 36 used when performing radiation imaging in a lying position. The space in front of the standing table 34 is set as the imaging position of the subject 38 when performing radiography in the standing position, and the upper space of the prone table 36 is used in performing radiography in the prone position. This is the imaging position of the subject 40.

The standing table 34 is provided with a holding unit 42 that holds the electronic cassette 20, and the electronic cassette 20 is held by the holding unit 42 when a radiographic image is taken in the standing position. Similarly, a holding unit 44 that holds the electronic cassette 20 is provided in the lying position table 36, and the electronic cassette 20 is held by the holding unit 44 when a radiographic image is taken in the lying position.

Further, in the radiation imaging room 32, the radiation irradiation source 22A is arranged around a horizontal axis in order to enable radiation imaging in a standing position and in a supine position by radiation from a single radiation irradiation source 22A. A support movement mechanism 46 that can be rotated in the direction of arrow A in FIG. 2, can move in the vertical direction (in the direction of arrow B in FIG. 2), and can move in the horizontal direction (in the direction of arrow C in FIG. 2). Is provided. A drive source that moves (including rotation) in the directions of arrows A to C in FIG.

On the other hand, the cradle 28 is formed with an accommodating portion 28A capable of accommodating the electronic cassette 20.

When the electronic cassette 20 is not used, the built-in battery is charged in a state of being accommodated in the accommodating portion 28A of the cradle 28. When a radiographic image is taken, the electronic cassette 20 is taken out of the cradle 28 by a radiographer or the like, and the photographing posture is established. If it is in the upright position, it is held in the holding part 42 of the standing table 34, and if it is in the upright position, it is held in the holding part 44 of the standing table 36.

Here, in the imaging system 16 according to the present embodiment, various types of information are transmitted and received by radio communication between the radiation generator 24 and the console 30 and between the electronic cassette 20 and the console 30 (details will be described later). .

The electronic cassette 20 is not used only in the state of being held by the holding portion 42 of the standing base 34 or the holding portion 44 of the prone position base 36. When photographing, it can be used in a state where it is not held by the holding unit.

The electronic cassette 20 includes a radiation detector described later. The built-in radiation detector is an indirect conversion method that converts radiation into light with a scintillator and then converts it into charges with a photoelectric conversion element such as a photodiode, and a direct conversion method that converts radiation into charges with a semiconductor layer such as amorphous selenium. Either may be used. The direct conversion type radiation detector is configured by laminating a photoelectric conversion layer that absorbs radiation X and converts it into charges on a TFT active matrix substrate. The photoelectric conversion layer is made of amorphous a-Se (amorphous selenium) containing, for example, selenium as a main component (for example, a content rate of 50% or more), and when irradiated with radiation X, a charge corresponding to the amount of irradiated radiation. By generating a certain amount of charge (electron-hole pairs) internally, the irradiated radiation X is converted into a charge. An indirect conversion type radiation detector indirectly uses a phosphor material and a photoelectric conversion element (photodiode) instead of the radiation-to-charge conversion material that directly converts the radiation X such as amorphous selenium into an electric charge. It may be converted into an electric charge. As phosphor materials, terbium activated gadolinium oxysulfide (Gd ₂ O ₂ S: Tb) (abbreviation GOS) and thallium activated cesium iodide (CsI: Tl) are well known. In this case, radiation X-light conversion is performed by the phosphor material, and light-charge conversion is performed by the photodiode of the photoelectric conversion element. The electronic cassette 20 according to the present embodiment will be described as including an indirect conversion radiation detector.

3A is a schematic cross-sectional view schematically showing the configuration of the four pixel portions of the radiation detector 26 provided in the electronic cassette 20, and FIG. 3B is a diagram showing the electrical configuration of the pixel portion of the radiation detector 26. It is.

As shown in FIG. 3A, in the radiation detector 26, a signal output unit 52, a sensor unit 54 (TFT substrate 74), and a scintillator 56 are sequentially laminated on an insulating substrate 50, and the signal output unit 52, The sensor unit 54 constitutes a pixel group of the TFT substrate 74. That is, the plurality of pixels are arranged in a matrix on the substrate 50, and the signal output unit 52 and the sensor unit 54 in each pixel are configured to overlap each other. An insulating film 53 is interposed between the signal output unit 52 and the sensor unit 54.

The scintillator 56 is formed on the sensor unit 54 via a transparent insulating film 58, and forms a phosphor that emits light by converting radiation incident from above (opposite side of the substrate 50) or below into light. It is what. Providing such a scintillator 56 absorbs radiation transmitted through the subject and emits light.

The wavelength range of light emitted by the scintillator 56 is preferably in the visible light range (wavelength 360 nm to 830 nm), and in order to enable monochrome imaging by the radiation detector 26, the wavelength range of green is included. Is more preferable.

Specifically, the phosphor used in the scintillator 56 preferably contains cesium iodide (CsI) when imaging using X-rays as radiation, and has an emission spectrum at 420 nm to 700 nm when irradiated with X-rays. It is particularly preferable to use (Tl) (cesium iodide with thallium added). Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm.

In this embodiment, an example of applying a “surface reading method (ISS: Irradiation Side Sampling)” in which a TFT substrate 74 is disposed on the radiation irradiation surface side of the scintillator 56 is shown. A “backside scanning method (PSS: Penetration Side Sampling)” in which a TFT substrate is disposed on the opposite side may be applied. Since the scintillator emits light more strongly on the radiation incident side, the surface reading method (ISS) in which the TFT substrate is disposed on the radiation incident side of the scintillator is the back surface reading method (PSS) in which the TFT substrate is disposed on the side opposite to the radiation incident side of the scintillator. ) ”, The light emission position of the scintillator is closer, so the resolution of the radiographic image obtained by imaging is higher, and the amount of light received by the TFT substrate is increased, resulting in improved sensitivity of the radiographic image. To do.

The sensor unit 54 includes an upper electrode 60, a lower electrode 62, and a photoelectric conversion film 64 disposed between the upper and lower electrodes. The photoelectric conversion film 64 absorbs light emitted from the scintillator 56 and generates electric charges. It is composed of an organic photoelectric conversion material.

The upper electrode 60 is preferably made of a conductive material that is transparent at least with respect to the emission wavelength of the scintillator 56 because light generated by the scintillator 56 needs to be incident on the photoelectric conversion film 64. It is preferable to use a transparent conductive oxide (TCO) having a high light transmittance and a low resistance value. Although a metal thin film such as Au can be used as the upper electrode 60, the TCO is preferable because it tends to increase the resistance when it is desired to obtain a transmittance of 90% or more. For example, ITO, IZO, AZO, FTO, SnO ₂ , TiO ₂ , ZnO _{2 and the} like can be preferably used, and ITO is most preferable from the viewpoint of process simplicity, low resistance, and transparency. Note that the upper electrode 60 may have a single configuration common to all pixels, or may be divided for each pixel.

The photoelectric conversion film 64 includes an organic photoelectric conversion material, absorbs light emitted from the scintillator 56, and generates electric charge according to the absorbed light. In this way, the photoelectric conversion film 64 including the organic photoelectric conversion material has a sharp absorption spectrum in the visible region, and electromagnetic waves other than light emitted by the scintillator 56 are hardly absorbed by the photoelectric conversion film 64, and X-rays are obtained. The noise generated by the radiation such as being absorbed by the photoelectric conversion film 64 can be effectively suppressed.

The organic photoelectric conversion material of the photoelectric conversion film 64 is preferably such that its absorption peak wavelength is closer to the emission peak wavelength of the scintillator 56 in order to absorb light emitted by the scintillator 56 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 56, but if the difference between the two is small, the light emitted from the scintillator 56 can be sufficiently absorbed. . Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength with respect to the radiation of the scintillator 56 is preferably within 10 nm, and more preferably within 5 nm.

Examples of the organic photoelectric conversion material that can satisfy such conditions include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength in the visible region of quinacridone is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 56, the difference in peak wavelength can be made within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 64 can be substantially maximized. Note that in this embodiment, the photoelectric conversion film 64 including an organic photoelectric conversion material is described as an example. However, the present invention is not limited thereto, and the photoelectric conversion film 64 may be a material that absorbs light and generates charges. For example, other materials such as amorphous silicon may be applied. When the photoelectric conversion film 64 is composed of amorphous silicon, it can be configured to absorb light emitted from the scintillator over a wide wavelength range.

The sensor unit 54 of each pixel only needs to include at least the lower electrode 62, the photoelectric conversion film 64, and the upper electrode 60, but in order to suppress an increase in dark current, the electron blocking film 66 and the hole blocking film 68 It is preferable to provide at least one, and it is more preferable to provide both.

The electron blocking film 66 can be provided between the lower electrode 62 and the photoelectric conversion film 64. When a bias voltage is applied between the lower electrode 62 and the upper electrode 60, electrons are transferred from the lower electrode 62 to the photoelectric conversion film 64. It is possible to suppress the dark current from increasing due to the injection of. An electron donating organic material can be used for the electron blocking film 66.

The hole blocking film 68 can be provided between the photoelectric conversion film 64 and the upper electrode 60. When a bias voltage is applied between the lower electrode 62 and the upper electrode 60, the hole blocking film 68 is transferred from the upper electrode 60 to the photoelectric conversion film 64. It is possible to suppress the increase in dark current due to the injection of holes. An electron-accepting organic material can be used for the hole blocking film 68.

The signal output unit 52 corresponds to the lower electrode 62, a capacitor 70 that accumulates the electric charge transferred to the lower electrode 62, and a field effect thin film transistor (Thin) that converts the electric charge accumulated in the capacitor 70 into an electric signal and outputs it. Film-Transistor (hereinafter sometimes simply referred to as a thin film transistor) 72 is formed. The region in which the capacitor 70 and the thin film transistor 72 are formed has a portion that overlaps the lower electrode 62 in plan view. With this configuration, the signal output unit 52 and the sensor unit 54 in each pixel are thick. There will be overlap in the vertical direction. In order to minimize the plane area of the radiation detector 26 (pixel), it is desirable that the region where the capacitor 70 and the thin film transistor 72 are formed is completely covered with the lower electrode 62.

As shown in FIG. 3B, the signal output unit 52 in the pixels arranged in a matrix is extended in a certain direction (row direction), and a plurality of gate wirings for turning on and off the thin film transistors 72 of the individual pixels. G and a plurality of data lines D are provided to read accumulated charges from the capacitor 70 through the thin film transistor 72 that is turned on and extends in a direction orthogonal to the gate line G. Individual gate lines G are connected to a gate line driver 71, and individual data lines D are connected to a signal processing unit 73. When electric charges are accumulated in the capacitors 70 of the individual pixel units, the thin film transistors 72 of the individual pixel units are sequentially turned on in units of rows by a signal supplied from the gate line driver 71 via the gate wiring G. The electric charge accumulated in the capacitor 70 of the pixel portion in which the thin film transistor 72 is turned on is transmitted through the data wiring D as an analog electric signal and input to the signal processing portion 73. Therefore, the electric charges accumulated in the capacitors 70 of the individual pixel portions are sequentially read out in units of rows.

Further, the gate line driver 71 sequentially outputs an on signal to each gate line G one line at a time in one image reading operation, and reads out the electric charge accumulated in the capacitor 70 of each pixel unit line by line. In addition to the (progressive scanning method), an ON signal is sequentially output from the gate line driver 71 to each gate wiring G by a plurality of lines (for example, two lines or four lines) in one image readout operation, and each pixel is formed by a plurality of lines. It is possible to read out the charge accumulated in the capacitor 70 of the unit (by combining and reading out the charges of the pixels read out simultaneously) in the binning readout method, and sequentially read out the image into the readout method and the binning readout method. Can be switched.

The sequential scanning method and the gate wiring G are divided into odd and even rows for each row, and an ON signal is output to the odd or even gate wiring G for each image reading operation. Thus, the image reading method may be switched between an interlaced scanning method (interlaced scanning method) in which charges accumulated in each pixel portion are alternately read for each line.

Also, the signal processing unit 73 and the gate line driver 71 are connected to a cassette control unit 69, and the gate control unit 69 controls the gate line driver 71 and the signal processing unit 73. The cassette control unit 69 is composed of a microcomputer including a CPU, ROM, RAM, HDD, fresh memory, and the like.

Further, the arrangement of each pixel in the radiation detector 26 is not limited to the matrix arrangement arranged in rows and columns, and other arrangements such as a staggered arrangement may be applied. In addition, the pixel shape may be a rectangular pixel shape or a polygonal shape such as a honeycomb shape.

FIG. 4 is a block diagram illustrating a schematic configuration of the signal processing unit 73 of the radiation detector 26 according to the present embodiment, and FIG. 5 focuses on one pixel portion of the radiation detector 26 according to the present embodiment. It is a figure which shows an equivalent circuit.

As shown in FIG. 4, the electric charge photoelectrically converted by the scintillator 56 is read and output to the signal processing unit 73 when the thin film transistor 72 is turned on.

As shown in FIG. 4, the signal processing unit 73 includes a charge amplifier 75, a sample hold circuit 76, a multiplexer 77, and an A / D converter 78.

The electric charge read out by the thin film transistor 72 is integrated by the charge amplifier 75, amplified by a predetermined amplification factor, held by the sample hold circuit, and output to the A / D converter 78 via the multiplexer 77. . An analog signal is converted into a digital signal by the A / D converter 78 so that image processing can be performed.

More specifically, as shown in FIG. 5, the source of the thin film transistor 72 is connected to the data line D, and the data line D is connected to the charge amplifier 75. The drain of the thin film transistor 72 is connected to the capacitor 70, and the gate of the thin film transistor 72 is connected to the gate wiring G.

The charge signal transmitted through each data line D is integrated by the charge amplifier 75 and held in the sample and hold circuit 76. The charge amplifier 75 is provided with a reset switch 79. While the reset switch 79 is turned off, the charge is read out and the charge signal is held in the sample hold circuit 76. When the reading of the charge is completed, the reset switch 79 is turned on to release the charge remaining in the integrating capacitor C1 of the charge amplifier 75 and reset it.

The charge signal held in the sample and hold circuit 76 is converted into an analog voltage, and sequentially (serially) input to the multiplexer 77, and converted into digital image information by the A / D converter 78.

The cassette control unit 69 controls on / off of the thin film transistor 72 and on / off of the reset switch 79 of the charge amplifier 75.

FIG. 6 is a control block diagram of the imaging system 16 according to the present embodiment.

The console 30 is configured as a server computer, and includes a display 80 that displays an operation menu, a captured radiographic image, and the like, and a plurality of keys, and an operation panel on which various information and operation instructions are input. 82.

The console 30 according to the present embodiment includes a CPU 84 that controls the operation of the entire apparatus, a ROM 86 that stores various programs including a control program in advance, a RAM 87 that temporarily stores various data, and various data. An HDD (Hard Disk Drive) 88 that stores and holds, a display driver 92 that controls display of various types of information on the display 80, and an operation input detector 90 that detects an operation state of the operation panel 82 are provided. .

Further, the console 30 transmits and receives various information such as irradiation conditions to be described later between the image processing device 23 and the radiation generation device 24 by wireless communication, and also various information such as image data with the electronic cassette 20. Are provided with an I / F (for example, a wireless communication unit) 96 and an I / O 94.

The CPU 84, ROM 86, RAM 87, HDD 88, display driver 92, operation input detection unit 90, I / O 94, and wireless communication unit 96 are connected to each other via a bus 98 such as a system bus or a control bus. Therefore, the CPU 84 can access the ROM 86, RAM 87, and HDD 88, controls display of various information on the display 80 via the display driver 92, and the radiation generator 24 via the wireless communication unit 96. Control of transmission and reception of various types of information with the electronic cassette 20 can be performed. Further, the CPU 84 can grasp the operation state of the user with respect to the operation panel 82 via the operation input detection unit 90.

On the other hand, the image processing device 23 includes an I / F (for example, a wireless communication unit) 100 that transmits and receives various types of information such as irradiation conditions to and from the console 30, and the electronic cassette 20 and the radiation generation device 24 based on the irradiation conditions. And an image processing control unit 102 for controlling. Further, the radiation generator 24 includes a radiation irradiation control unit 22 that controls radiation irradiation from the radiation irradiation source 22A.

The image processing control unit 102 includes a system control unit 104, a panel control unit 106, and an image processing control unit 108, and exchanges information with each other via a bus 110. The panel control unit 106 receives information from the electronic cassette 20 wirelessly or by wire, and the image processing control unit 108 performs image processing.

On the other hand, the system control unit 104 receives information such as tube voltage and tube current as irradiation conditions from the console 30, and irradiates radiation X from the radiation irradiation source 22A of the radiation irradiation control unit 22 based on the received irradiation conditions. Take control.

Here, reading of the electric charge photoelectrically converted by the scintillator 56 and stored in the capacitor 70 in the radiation detector 26 configured as described above will be described. FIG. 7 is a diagram showing an output waveform accompanying charge reading of the charge amplifier 75.

In the radiation detector 26, the charge accumulated in the capacitor 70 is read by turning on and off the thin film transistor 72. However, before the charge is read, the charge remaining in the integrating capacitor C1 of the charge amplifier 75 by the previous reading is read. In order to reset, the reset operation of the charge amplifier 75 is performed.

The reset operation by the charge amplifier 75 is performed by turning on and off the reset switch 79 by the cassette control unit 69. When the reset switch 79 is turned on by the cassette control unit 69, the output OP of the charge amplifier 75 is reset during the reset time trst as shown by the output voltage in FIG. At this time, charges are released with a time constant depending on the response characteristics of the charge amplifier 75, and the discharge of the charges is saturated at some point. Therefore, although the reset switch 79 is turned off, the charge CDS1 is superimposed when the reset switch 79 is turned off.

Then, the gate of the thin film transistor 72 (TFT gate) is turned on to read out the charge, and after the gate on time tgon elapses, the gate is turned off to complete the reading of the charge. Feedthrough noise is superimposed by turning the gate on and off, but is integrated by the charge amplifier 75, so that the feedthrough overlap is canceled out and the charge CDS2 is obtained. Here, since charge CDS2−charge CDS1 = actual output, the actual output is calculated by the sample and hold circuit.

Here, the charge CDS1 is not a constant charge but a random charge. If the reset period is short, the charge CDS1 cannot be released and the charge CDS1 becomes large. However, the charge CDS1 is simply shifted upward by the charge CDS1. There is no real harm in conditions such as shooting with few.

Therefore, in this embodiment, paying attention to the fact that there is no real harm even if the reset time is shortened in the case of shooting with a small amount of charge, and the shooting time is reduced by shortening the reset time when shooting with a small amount of charge. To shorten.

FIG. 8A is a diagram showing amplifier reset by the reset switch 79, reference sampling of the sample and hold circuit 76, signal sampling of the sample and hold circuit 76, and on / off timing of the gate of the thin film transistor 72 in the data read period, and FIG. FIG. 8C is a diagram in which the amplifier reset time is shortened.

In the present embodiment, if the amplifier reset time for shooting of an amount of charge larger than a predetermined amount of charge (for example, still image shooting or high-definition still image shooting) is T ₁ shown in FIG. As shown in FIG. 8C, in the case of shooting when the charge is expected to be lower (eg, moving image shooting, positioning moving image shooting for adjusting at least one of shooting position and timing, infant shooting, etc.) The amplifier reset time is shortened by shortening the ON time of the switch 79 to T ₂ (<T ₁ ). As a result, the readout time is shortened and the photographing time is shortened. Note that the amount of reduction in the amplifier reset time is determined in advance by experiments or the like.

Subsequently, the operation of the present embodiment will be described with reference to the flowcharts of FIGS.

FIG. 9 is a flowchart showing the radiographic imaging preparation control routine.

In step 200, it is determined whether or not a shooting instruction has been issued. If the determination is negative, the routine ends. If the determination is affirmative, the routine proceeds to step 202.

In step 202, an initial information input screen is displayed on the display 80, and the process proceeds to step 204. That is, the display driver 92 is controlled so that a predetermined initial information input screen is displayed on the display 80.

In step 204, it is determined whether or not predetermined information has been input. The process waits until the determination is affirmed, and the process proceeds to step 206. On the initial information input screen, for example, the name of the subject who is going to take a radiographic image, the part to be imaged, the posture at the time of imaging, and the irradiation condition of the radiation X at the time of imaging (in this embodiment, the radiation X is irradiated) Message for prompting the input of the tube voltage and tube current) and an input area for such information are displayed.

When the initial information input screen is displayed on the display 80, the photographer displays the name of the subject to be imaged, the region to be imaged, the posture at the time of imaging, and the irradiation conditions in the corresponding input areas on the operation panel 82. Enter through.

The radiographer enters the radiography room 32 together with the subject. For example, when the radiographer is in the supine position, the radio cassette 22A is supported while holding the electronic cassette 20 in the holding unit 44 of the corresponding prone position table 36. After positioning at the position, the subject is positioned (positioned) at a predetermined imaging position. In addition, when radiography is performed in a state where the imaging target site does not hold the electronic cassette 20 such as an arm or a leg on the holding unit, the subject and the electronic cassette 20 are ready to capture the imaging target site. And the radiation source 22A are positioned (positioned).

Thereafter, the radiographer leaves the radiation imaging room 32 and designates, for example, an end button displayed near the lower end of the initial information input screen via the operation panel 82. When an end button is designated by the photographer, step 204 is affirmed and the routine proceeds to step 206. In the flowchart of FIG. 9, step 204 is an infinite loop, but it may be forcibly terminated by operating a cancel button provided on the operation panel 82.

In step 206, information input on the initial information input screen (hereinafter referred to as “initial information”) is transmitted to the electronic cassette 20 via the wireless communication unit 96, and then the process proceeds to the next step 208. The irradiation conditions included in the initial information are set by transmitting the irradiation conditions to the radiation generator 24 via the wireless communication unit 96. In response to this, the image processing control unit 102 of the radiation generator 24 prepares for irradiation under the received irradiation conditions.

In the next step 210, the start of ABC control is instructed, and then the process proceeds to step 212, where the instruction information instructing the start of radiation irradiation is transmitted to the radiation generator 24 via the wireless communication unit 96. Ends.

Next, the flow of radiation irradiation control will be described according to the flowchart of FIG. FIG. 10 is a flowchart showing a radiation irradiation control routine.

In step 300, it is determined whether or not there has been an irradiation start instruction. If a negative determination is made, this routine ends. If an affirmative determination is made, the routine proceeds to step 302.

In step 302, the steady-state radiation dose (initial value) _XN is read, and the process proceeds to step 304.

In step 304, irradiation is started with the read steady-state radiation dose, and the process proceeds to step 306. That is, irradiation from the radiation irradiation source 22 </ b> A is started by applying a tube voltage and a tube current corresponding to the irradiation upper limit received from the console 30 to the radiation generator 24. The radiation X emitted from the radiation source 22A passes through the subject and reaches the electronic cassette 20.

In step 306, the currently stored radiation dose correction information is read, and the process proceeds to step 308. This radiation dose correction information is generated by ABC control and is stored as a correction coefficient ΔX.

In the next step 308, correction processing based on ABC control is executed, and the process proceeds to step 310. That is, based on the gradation signal (QL value) obtained from the electronic cassette 20, an average value of the QL values of the region of interest image is calculated, and the average value of the QL values is compared with a predetermined threshold value. The radiation dose is feedback controlled so as to converge to the threshold value.

In step 310, it is determined whether or not an instruction to end shooting is given. If the determination is affirmative, the process proceeds to step 312. If the determination is negative, the process returns to step 306 and the above-described processing is repeated.

In step 312, the irradiation is terminated, and the radiographic image capturing control is terminated.

Subsequently, the flow of image processing control will be described with reference to the flowchart of FIG. FIG. 11 is a flowchart showing an image processing control routine.

When the radiographic image capturing control is performed as described above, in step 400, gradation information for one frame is sequentially captured, and the process proceeds to step 402. That is, gradation signals generated by the TFT substrate 74 of the electronic cassette 20 are sequentially taken into the image processing control unit 102 under the control of the panel control unit 106. Before the gradation signal is captured by the image processing control unit 102, the gradation signal is sequentially captured in the cassette control unit 69 by a gradation signal capturing process described later, and the gradation signal captured by the cassette control unit 69 is sequentially displayed on the panel. The image is sent to the image processing control unit 102 under the control of the control unit 106.

In step 402, a still image is generated, and the process proceeds to step 403. That is, a still image is generated when a grayscale signal for one frame is captured. *

In step 403, it is determined whether or not moving image shooting is performed. If the determination is affirmative, the process proceeds to step 404. If the determination is negative, the image processing control is terminated as it is.

In step 404, the moving image editing process is performed, and the process proceeds to step 406. In the moving image editing process, moving image editing is performed by combining still images for each frame generated in step 402.

In step 406, image display processing is performed, and the process proceeds to step 408. In the image display process, the display driver 92 displays the moving image generated by the moving image editing process on the display 80 by sending it to the display driver 92.

In step 408, the region of interest is set, and the process proceeds to step 410. The region of interest is set by, for example, pattern matching or detecting a region with a large amount of movement, but the region of interest may be set by a user operation.

In step 410, the gradation signal of the set region of interest is extracted, and the process proceeds to step 412.

In step 412, the average QL value of the gradation signal of the region of interest is calculated and the process proceeds to step 414. In step 414, the pre-stored reference QL value is read and the process proceeds to step 416.

In step 416, the calculated average QL value is compared with the read reference QL value to determine whether correction is possible or not, and the process proceeds to step 418. For example, the determination as to whether correction is possible may be an on / off determination in which a predetermined amount of correction is performed if the difference is greater than or equal to a predetermined value in the comparison result, and no correction is performed if the difference is less than a predetermined value. Based on the difference, it may be a solution of a calculation using a predetermined calculation formula (for example, a calculation formula based on PID control or the like).

In step 418, radiation dose correction information ΔX is generated based on the comparison / correction determination result in step 416, and the process proceeds to step 420.

In step 420, the generated correction information ΔX is stored, and the image processing control is terminated.

Next, according to the flowchart of FIG. 12, the flow of the gradation signal capturing process performed by the cassette control unit 69 when the above-described gradation signals are sequentially captured will be described. FIG. 12 is a flowchart showing the gradation signal fetch processing routine.

When capturing a gradation signal, first, in step 500, it is determined whether or not the photographing is performed when the charge is expected to be lower than a predetermined value. In this determination, for example, it is determined whether or not the instructed shooting is moving image shooting, positioning moving image shooting, or infant shooting. If the determination is affirmative, the process proceeds to step 502, and if the determination is negative, the process proceeds to step 504. It should be noted that the determination is denied when a moving image continuous shooting for cutting out a still image is instructed even in moving image shooting. In other words, when cutting out still images from movie shooting, if the reset time is shortened as in the following processing, there is a possibility that charges will remain and adversely affect still images that require high definition. In the case of moving image continuous shooting for cutting out a still image, the reset time is not shortened for the shooting that is the target of the still image. For example, when still image shooting is performed at an arbitrary frame during moving image shooting, control is performed so as not to shorten the reset time for the still image shooting frame. “Cut out a still image from movie shooting” here means to cut out a still image by shooting a movie with still image shooting (still image shooting under still image shooting conditions) that increases the amount of charge during movie shooting. Represents that.

In step 502, the amplifier reset time of the charge amplifier 75 is set to a value shorter than a predetermined specified value, and the process proceeds to step 506. Note that the amount of shortening of the amplifier reset time is determined in advance through experiments or the like.

On the other hand, in step 504, the amplifier reset time of the charge amplifier 75 is set to a predetermined specified value, and the process proceeds to step 506.

In step 506, gradation signals for one frame are sequentially read, and the process proceeds to step 508. That is, in the case of shooting other than shooting when the charge is expected to be lower than the predetermined value, as shown in FIG. 8B, the amplifier reset time of the specified value is set, and the charge is expected to be lower than the predetermined value. In the case of shooting, as shown in FIG. 8C, the amplifier reset time when the reset switch 79 is turned on for each line is shortened below a specified value, and gradation signals are sequentially read out. As a result, in the case of imaging where the charge is expected to be lower than a predetermined value, the imaging time is shortened and the burden on the subject can be reduced.

In step 508, it is determined whether or not the photographing is finished. If the determination is negative, the process returns to step 500 and the above-described processing is repeated. When the determination is affirmed, the series of processing ends.

As described above, in this embodiment, when the charge is expected to be lower than a predetermined value such as moving image shooting, positioning moving image shooting, and infant shooting, the amplifier reset time of the charge amplifier 75 is set as an amplifier for other shooting. By reading out the electric charge accumulated in the capacitor 70 by photographing shorter than the reset time, the photographing time corresponding to the shortened amplifier reset time can be shortened.

Also, by shortening the imaging time, the radiation dose exposed to the subject can be reduced, and the burden on the subject can be reduced.

In the above embodiment, moving image shooting, positioning moving image shooting, infant shooting and the like are examples of shooting when the reset time of the charge amplifier 75 is shortened, that is, when the charge is expected to be lower than a predetermined value. However, the present invention is not limited to this, and in the case of shooting that is expected to have a lower charge than usual even in still image shooting (for example, pre-exposure that is shot in advance before shooting), the charge amplifier 75 The reset time may be shortened. Further, the reset time may be shortened as the electric charge generated by photographing is smaller. Furthermore, the reset time may be shortened according to the type of continuous shooting.

In the above-described embodiment, an example in which the reset time is controlled to be shortened in the case of moving image shooting that has relatively less charge than still image shooting has been described. However, the present invention is not limited to this. If the charge amount estimated from the order is smaller than a predetermined charge amount, the reset time may be shortened. Alternatively, the electronic cassette 20 detects an irradiation amount of the radiation X with respect to the radiation detector 26 and terminates the capturing of the radiation image based on the accumulated irradiation amount. For example, the electronic cassette 20 controls AEC (Automatic Exposure Control). Since the control process (the irradiation control process described above) is performed, the reset time is controlled based on the result of the AEC control process so that the reset time is shortened when the amount of charge generated by imaging is smaller than a predetermined value. You may make it do.

In the above embodiment, when the charge is expected to be lower than the predetermined value, the reset time is shortened. However, the reset time is shortened, that is, the charge is expected to be lower than the predetermined value. For example, the photographing in the case where the charge is generated is not limited to the above. For example, photographing with a charge that is lower in charge generated in a specific pixel than in other pixels or a predetermined value may be applied. It may be possible to apply photographing in which the average charge or maximum charge of a specific area (or the whole area) is lower than a predetermined charge or an average charge or maximum charge other than the specific area, or a specific pixel or specific charge. You may make it apply imaging | photography with the electric charge of an area | region low compared with still image photography. Alternatively, representative values (for example, an average value, a centroid value, and a maximum value of a specific region) assumed in a predetermined specific region (for example, a region of interest (ROI: Region Of Interest) or a predetermined pixel) at the time of moving image shooting Etc.) may be shortened when it is estimated that the value is lower or lower than a predetermined value.

The processing shown in each flowchart in the above embodiment may be stored and distributed as various programs in various storage media.
(Modification 1)
(A) In each pixel of the radiation detector in which a plurality of pixels configured to include a sensor unit that generates charges according to the irradiated radiation and a switching element for reading out the charges generated by the sensor unit are arranged A reset means for resetting the charge of the integrating capacitor for integrating the charge is provided, and an electric signal due to the charge read out from the corresponding pixel by the switching element is set at a predetermined amplification factor. The charge remaining before photographing is reset by the reset means in the amplification means for amplifying,
(B) When the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value, the switch is set so that the reset time by the reset means in (a) is shorter than a predetermined time. Control means,
A non-transitory computer-readable storage medium storing a radiographic imaging control program for causing a computer to execute processing.
(Modification 2)
In (b), the computer-readable storage medium according to the first modification, in which the switch unit is controlled so that the reset time becomes shorter as the charge generated by the photographing is smaller.
(Modification 3)
In (b), in the case of moving image shooting, the computer-readable storage medium according to Modification 1 or Modification 2 that controls the switch unit so that the reset time by the reset unit is shorter than still image shooting .
(Modification 4)
In (b), in the case of positioning moving image shooting for adjusting at least one of the shooting position and the shooting timing, the switch unit is controlled such that the reset time is shorter than a predetermined time. 4. The computer-readable storage medium according to any one of 3.
(Modification 5)
5. The computer-readable storage medium according to any one of Modifications 1 to 4, wherein the switch unit is controlled so that the reset time is shortened according to the type of continuous shooting in (b).
(Modification 6)
In (b), in the case of video continuous shooting that cuts out a still image from a moving image, the reset is performed at the predetermined time without shortening the reset time for shooting that is a target of a still image. The computer-readable storage medium according to any one of Modifications 1 to 5 for controlling the reset means.
The entire disclosure of Japanese Patent Application No. 2012-036716 is incorporated herein by reference.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A radiation detector in which a plurality of pixels configured to include a sensor unit that generates electric charge according to the irradiated radiation and a switching element for reading out the electric charge generated in the sensor unit;
Reset means provided corresponding to each pixel of the radiation detector and resetting the charge of an integrating capacitor for integrating the charge is provided, and the electric power generated by the charge read by the switching element from the corresponding pixel is provided. Amplifying means for amplifying the signal at a predetermined amplification rate;
Control means for controlling the switch means so that the reset time by the reset means is shorter than a predetermined time when the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value. When,
A radiographic imaging control apparatus comprising:
2. The radiographic imaging control apparatus according to claim 1, wherein the control unit controls the switch unit so that the reset time becomes shorter as the charge generated by the imaging is smaller.
3. The radiographic imaging control according to claim 1, wherein the control unit controls the switch unit so that the reset time by the reset unit is shorter in the case of moving image shooting than in the case of still image shooting. apparatus.
The control unit controls the switch unit so that the reset time is shorter than a predetermined time in the case of positioning moving image shooting for adjusting at least one of a shooting position and a shooting timing. 4. The radiographic image capturing control apparatus according to any one of items 3.
The radiographic imaging control apparatus according to any one of claims 1 to 4, wherein the control unit controls the switch unit so that the reset time is shortened according to a type of continuous imaging.
In the case of video continuous shooting that cuts out a still image from a moving image, the control means resets the predetermined time without shortening the reset time for shooting that is a target of a still image. The radiographic imaging control apparatus according to any one of claims 1 to 5, which controls the reset means.
A radiographic imaging control device according to any one of claims 1 to 6,
Radiation irradiating means for irradiating the radiation detector through the subject with radiation;
Radiographic imaging system equipped with.
(A) In each pixel of the radiation detector in which a plurality of pixels configured to include a sensor unit that generates charges according to the irradiated radiation and a switching element for reading out the charges generated by the sensor unit are arranged A reset means for resetting the charge of the integrating capacitor for integrating the charge is provided, and an electric signal due to the charge read out from the corresponding pixel by the switching element is set at a predetermined amplification factor. The charge remaining before photographing is reset by the reset means in the amplification means for amplifying,
(B) When the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value, the switch is set so that the reset time by the reset means in (a) is shorter than a predetermined time. Control means,
A method for controlling a radiographic imaging apparatus.
The control method of the radiographic imaging apparatus according to claim 8, wherein the switch unit is controlled so that the reset time becomes shorter as the electric charge generated by the imaging is smaller in (b).
The radiographic imaging apparatus according to claim 8 or 9, wherein in (b), in the case of moving image shooting, the switch unit is controlled so that a reset time by the reset unit is shorter than still image shooting. Control method.
In (b), in the case of positioning moving image shooting for adjusting at least one of the shooting position and the shooting timing, the switch means is controlled so that the reset time is shorter than a predetermined time. The control method of the radiographic imaging apparatus of any one of 10.
The method of controlling a radiographic imaging apparatus according to any one of claims 8 to 11, wherein, in (b), the switch unit is controlled so that the reset time is shortened according to a type of continuous imaging.
In (b), in the case of video continuous shooting that cuts out a still image from a moving image, the reset is performed at the predetermined time without shortening the reset time for shooting that is a target of a still image. The method of controlling a radiographic imaging apparatus according to any one of claims 8 to 12, wherein the reset means is controlled.
(A) In each pixel of the radiation detector in which a plurality of pixels configured to include a sensor unit that generates charges according to the irradiated radiation and a switching element for reading out the charges generated by the sensor unit are arranged A reset means for resetting the charge of the integrating capacitor for integrating the charge is provided, and an electric signal due to the charge read out from the corresponding pixel by the switching element is set at a predetermined amplification factor. The charge remaining before photographing is reset by the reset means in the amplification means for amplifying,
(B) When the charge generated by imaging using the radiation detector is expected to be lower than a predetermined value, the switch is set so that the reset time by the reset means in (a) is shorter than a predetermined time. Control means,
A radiographic imaging control program for causing a computer to execute processing.
The radiographic imaging control program according to claim 14, wherein the switch unit is controlled so that the reset time becomes shorter as the charge generated by the imaging is smaller in (b).
The radiographic image capturing control according to claim 14 or 15, wherein, in (b), in the case of moving image capturing, the switch unit is controlled so that the reset time by the reset unit is shorter than still image capturing. program.
In (b), in the case of positioning moving image shooting for adjusting at least one of the shooting position and the shooting timing, the switch means is controlled so that the reset time is shorter than a predetermined time. The radiographic imaging control program according to any one of 16.
The radiographic imaging control program according to any one of claims 14 to 17, wherein, in (b), the switch means is controlled so that the reset time is shortened according to the type of continuous imaging.
In (b), in the case of video continuous shooting that cuts out a still image from a moving image, the reset is performed at the predetermined time without shortening the reset time for shooting that is a target of a still image. The radiographic image capturing control program according to any one of claims 14 to 18, which controls the reset means.