JP5648404B2 - Radiographic imaging system and radiographic imaging device - Google Patents

Description

  The present invention relates to a radiographic image capturing system and a radiographic image capturing apparatus.

  A so-called direct type radiographic imaging device that generates electric charges by a detection element in accordance with the dose of irradiated radiation such as X-rays and converts it into an electrical signal, or other radiation such as visible light with a scintillator or the like. Various types of so-called indirect radiographic imaging devices have been developed that convert charges into electromagnetic signals after they have been converted into electromagnetic waves of a wavelength, and then generated by photoelectric conversion elements such as photodiodes in accordance with the energy of the converted and irradiated electromagnetic waves. Yes. In the present invention, the detection element in the direct type radiographic imaging apparatus and the photoelectric conversion element in the indirect type radiographic imaging apparatus are collectively referred to as a radiation detection element.

  This type of radiographic imaging apparatus is known as an FPD (Flat Panel Detector), and conventionally formed integrally with a support base (or a bucky apparatus) (see, for example, Patent Document 1). A portable radiographic imaging device in which an element or the like is housed in a housing has been developed and put into practical use (see, for example, Patent Documents 2 and 3).

  In such a radiographic imaging apparatus, even when no radiation is irradiated, dark charges are generated in each radiation detection element due to thermal excitation of the radiation detection element due to heat, and the charge accumulated in the radiation detection element, that is, an image The data includes the offset due to this dark charge. Therefore, in order to acquire a high-quality radiographic image, dark image acquisition, in which data for offset due to dark charges (hereinafter referred to as “dark image data”) is usually read from each radiation detection element and a correction dark image is acquired. In many cases, the processing is performed subsequent to the radiographic image capturing processing.

  Further, in such a radiographic imaging apparatus, in order to acquire a high-quality radiographic image, usually before radiographic imaging, that is, before accumulating charges generated by radiation irradiation in each radiation detection element. Then, reset processing for resetting each radiation detection element by discharging extra charges such as dark charges accumulated in each radiation detection element is performed (see, for example, Patent Documents 4 and 5).

  Specifically, in the reset process, for example, as shown in FIG. 9 to be described later, an on-voltage is applied to each of the lines L1 to Lx of the scanning line 5 from the gate driver 15b of the scanning driving unit 15, and the scanning line 5 Each thin film transistor (hereinafter referred to as “TFT”) 8 which is a switching means having a gate electrode 8g (indicated as G in the drawing) connected to each of the lines L1 to Lx is turned on. As a result, excess charges are emitted from each radiation detection element 7 to each signal line 6 via each TFT 8.

  In this reset process, for example, as shown in FIG. 11 described later, an ON voltage is sequentially applied from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5, and the TFTs 8 to be turned on are sequentially switched. Often done.

In the case of the radiographic image capturing process after the reset process, the radiographic image is captured by transitioning to the charge accumulation mode, and the charge generated or accumulated in each radiation detecting element 7 by the radiation irradiation, that is, image data is stored. It is generated and accumulated in each radiation detection element 7. In the subsequent readout process, the surplus charges remaining in the radiation detection element 7 as described above are also read from each radiation detection element 7 together with the true image data.
In the case of the dark image acquisition process after the reset process, the correction dark image is acquired by shifting to the charge storage mode, and is generated and stored in each radiation detection element 7 in a state where no radiation is irradiated. Charge, that is, dark image data, is generated and stored in each radiation detection element 7. Then, the dark image data is read from each radiation detection element 7 in the subsequent reading process.

  That is, the dark image acquisition process is normally performed in the same sequence as the radiographic image capturing process, for example, as shown in FIG. 12 described later. In the dark image acquisition process, the radiographic image capturing process is performed during the charge accumulation mode. In contrast, the radiation image capturing apparatus is left in a state where no radiation is irradiated.

  At that time, regardless of the time from the start to the end of the charge accumulation mode, from the end of the radiographic image capture, that is, from the end of the charge accumulation mode of the radiographic image capture process, to start the correction dark image acquisition, that is, the dark image acquisition process. In many cases, the time until the start of the charge accumulation mode is set to be constant.

  At that time, in order to acquire a more accurate correction dark image, that is, the dark charge amount generated and accumulated during acquisition of the correction dark image is generated and accumulated during radiographic image capturing. In order to approach the amount of charge, the time from the start to the end of the charge accumulation mode of the radiographic image capturing process is set to coincide with the time from the start to the end of the charge accumulation mode of the dark image acquisition process. There are many cases.

By the way, the radiographic imaging device stands by in a sleep mode in which power is not supplied to a functional unit or the like related to radiographic imaging so that useless power consumption can be suppressed. Then, a predetermined trigger for starting imaging such as reception of an imaging start instruction signal switches to a standby state in which power is also supplied to a functional unit related to radiographic imaging, and the process proceeds to radiographic imaging processing and reset processing is performed. Often configured to do.
Further, as shown in FIG. 13 to be described later, for example, dark charges are not generated while power is not supplied to the functional unit related to radiographic imaging, but power is not supplied to the functional unit related to radiographic imaging. It is known that it occurs as soon as the supply is started, and the rate of generation gradually decreases and becomes constant over time.

  That is, when switching to the standby state by a predetermined trigger for starting photographing, dark charges are immediately generated, and thereafter the generation speed gradually decreases. Therefore, when switching to the standby state by a predetermined trigger for starting imaging, depending on the time from the start to the end of the reset mode of the radiographic imaging process (hereinafter referred to as “reset time”), charge accumulation in the radiographic imaging process is performed. Even if the time from the start to the end of the mode matches the time from the start to the end of the charge accumulation mode of the dark image acquisition process, it occurs during the acquisition of the radiation image and the acquisition of the correction dark image. The amount of accumulated dark charge may vary greatly.

  Specifically, since the dark charge generation speed gradually decreases and becomes constant over time, radiographic images are taken before the correction dark image is acquired, and before the dark charge generation speed becomes constant. That is, when a radiographic image is captured while the generation rate of the dark charge is gradually decreasing, for example, as shown in FIGS. 14 and 15 described later, it is generated and accumulated during acquisition of the correction dark image. The amount of dark charge generated and accumulated during radiographic image capture (the left side in FIGS. 14 and 15) than the amount of dark charge (the amount corresponding to the area of the hatched portion on the right side in FIGS. 14 and 15) (Amount corresponding to the area of the shaded portion). For this reason, the amount of dark charge that is generated and accumulated during radiographic image capturing and acquisition of a correction dark image may differ greatly.

  If the amount of dark charge generated and accumulated during radiographic image acquisition and correction dark image acquisition differs greatly, it is obtained as dark image data and offset data due to dark charge contained in the image data. There is a large difference between the offset data and the offset correction cannot be performed accurately, and an image abnormality may occur due to automatic gradation processing. In the following, the difference between the offset data due to the dark charge included in the image data and the offset data obtained as the dark image data, specifically, from the offset due to the dark charge included in the image data. The difference obtained by subtracting the offset obtained as dark image data is called an offset error.

However, since the dark charge generation rate will become constant over time, if you take a radiograph after the reset time is set longer and the dark charge generation rate becomes almost constant, the correction will be performed during radiographic image capture and for correction. There may be no difference in the amount of dark charge generated and accumulated during acquisition of the dark image, and the offset error may be “0”.
Therefore, by performing exposure (irradiation of radiation) after the elapse of a desired time from the start of the standby state in which power is supplied to the functional unit or the like related to radiographic imaging, the dark current is stabilized and the generation rate of the dark charge is substantially reduced. There has been proposed a photoelectric conversion device such as a radiographic image capturing device capable of capturing a radiographic image after becoming constant (see, for example, Patent Document 6).

JP-A-9-73144 JP 2006-058124 A JP-A-6-342099 Japanese Patent Laid-Open No. 5-240960 JP-A-9-131337 JP-A-9-294229

However, it is not necessary to set a long reset time so that the dark charge generation rate is substantially constant.
Specifically, when other errors such as the influence of noise are taken into account, the offset error does not have to be “0” and may be a value equal to or less than a predetermined threshold, that is, a value capable of acquiring a radiographic image having an appropriate image quality. That's fine. Therefore, from the viewpoint of efficiently acquiring a radiographic image without taking time, it is not necessary to set a long reset time so that the dark charge generation rate becomes substantially constant.

  On the other hand, if a radiographic image is taken while the generation rate of dark charges is gradually decreasing, it is generated and accumulated during radiographic image acquisition and correction dark image acquisition as described above. Therefore, as in the photoelectric conversion device described in Patent Document 6, the time for capturing a radiographic image, that is, the time from the start to the end of the charge accumulation mode of the radiographic image capturing process (hereinafter “ If the reset time is constant regardless of the "accumulation time"), there is a problem that the reset time is too long and the radiographic image cannot be acquired efficiently without taking time. There is a possibility that a problem that a radiographic image of image quality cannot be acquired occurs.

Specifically, as described above, the time from the end of radiographic image capture to the start of correction dark image acquisition is often set to be constant regardless of the accumulation time. Therefore, the shorter the accumulation time, the closer the radiographic image capturing start time (ta in FIGS. 14 and 15) and the correction dark image acquisition start time (tb in FIGS. 14 and 15) are, and the longer the accumulation time is. The longer the radiographic image capturing start time (ta) is, the farther the correction dark image acquisition starting time (tb) is.
Therefore, when taking a radiographic image while the rate of dark charge generation is gradually decreasing, if the reset time is constant regardless of the accumulation time, the shorter the accumulation time, the more the radiographic image is being captured and corrected. There is no significant difference in the amount of dark charge that is generated and accumulated during the acquisition of dark images, and the longer the accumulation time, the more it occurs and accumulates during radiographic image acquisition and correction dark image acquisition. In many cases, a large difference occurs in the amount of dark charge.

That is, when radiographic imaging is performed while the dark charge generation rate is gradually decreasing, if the reset time is constant regardless of the accumulation time, the shorter the accumulation time, the smaller the offset error becomes. There is a high possibility that the threshold value will be below the threshold value, and the longer the accumulation time, the greater the possibility that the offset error will increase and exceed the predetermined threshold value.
In this case, as described above, the fact that the offset error is below the predetermined threshold can be said to be sufficient for the reset time. Therefore, the shorter the accumulation time, the more the reset time is sufficient and the radiographic image is efficiently captured without taking time. There is a high possibility that a problem that it cannot be acquired occurs. On the other hand, if the offset error exceeds a predetermined threshold, it can be said that the reset time is insufficient, so that the longer the accumulation time, the less the reset time is, and it is not possible to acquire a radiographic image with an appropriate image quality. Is likely to occur.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a radiographic image capturing system and a radiographic image capturing apparatus capable of efficiently acquiring a radiographic image with appropriate image quality.

In order to solve the above-described problem, the radiographic imaging system of the present invention includes:
A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
Subsequent to the radiographic image capturing process, it is configured to perform a dark image acquisition process for acquiring a correction dark image for correcting the radiographic image,
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Control means for controlling at least the scanning drive means and the readout circuit,
The control means includes
During the radiographic imaging process,
A reset process is performed to reset the radiation detection element by discharging the electric charge from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit,
When at least the minimum reset time elapses, the scan driving means transitions to a charge accumulation mode in which the charges are accumulated in the radiation detection elements by applying the off voltage to all the scanning lines.
When a predetermined accumulation time elapses, the charge is discharged from the radiation detection element by applying the on-voltage to the scanning line from the scanning driving unit, and the discharged charge is transferred to the image data by the readout circuit. The image data read processing is performed to make a transition to a read mode,
During the dark image acquisition process,
Perform the reset process,
When a predetermined reset time has elapsed, the state transitions to the charge accumulation mode and waits without being irradiated with the radiation,
It is configured to transition to the readout mode when a predetermined standby time has elapsed,
The minimum reset time is a time determined in advance according to the accumulation time.

Moreover, the radiographic imaging device of the present invention is
In a radiographic image capturing apparatus that performs radiographic image capturing processing for capturing a radiographic image,
Subsequent to the radiographic image capturing process, it is configured to perform a dark image acquisition process for acquiring a correction dark image for correcting the radiographic image,
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
By converting the by said charge emitted from the radiation detecting elements in images data, and a read circuit for performing image data reading processing from the radiation detecting device reads out the image data of the radiographic image,
Control means for controlling at least the scanning drive means and the readout circuit,
The control means includes
During the radiographic imaging process,
A reset process is performed to reset the radiation detection element by discharging the electric charge from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit,
When at least the minimum reset time elapses, the scan driving means transitions to a charge accumulation mode in which the charges are accumulated in the radiation detection elements by applying the off voltage to all the scanning lines.
When a predetermined accumulation time elapses, the charge is discharged from the radiation detection element by applying the on-voltage to the scanning line from the scanning driving unit, and the discharged charge is transferred to the image data by the readout circuit. The image data read processing is performed to make a transition to a read mode,
During the dark image acquisition process,
Perform the reset process,
When predetermined reset time has elapsed, it releases the transition to the charge storage mode rays are available at the state of not irradiated,
It is configured to transition to the readout mode when a predetermined standby time has elapsed,
The minimum reset time is a time determined in advance according to the accumulation time.

  According to the radiation image capturing system and the radiation image capturing apparatus of the system as in the present invention, the radiation image capturing apparatus acquires a dark image for correction for correcting the radiation image subsequent to the radiation image capturing process. The acquisition unit is configured to perform acquisition processing, and at the time of radiographic imaging processing, the control unit of the radiographic imaging device performs reset processing that releases the charge from the radiation detection element and resets the radiation detection element, and performs the reset processing. After at least the minimum reset time has elapsed since the execution, the mode transits to a charge accumulation mode in which charges are accumulated in the radiation detection element, and after a predetermined accumulation time has elapsed from the transition to the charge accumulation mode, the charge is released from the radiation detection element. Image data read processing by causing the readout circuit to convert the discharged charges into image data. It is configured to transition to a read mode to perform. The minimum reset time is a time determined in advance according to the accumulation time.

That is, the minimum reset time required for the reset process performed during the radiographic image capturing process can be changed according to the accumulation time.
Therefore, there is a problem that occurs when the reset time is constant regardless of the accumulation time, specifically, a problem that the reset time is too long to efficiently acquire a radiographic image without taking time, and a reset time. Inadequate and the problem that it is not possible to acquire a radiographic image having an appropriate quality can be avoided, and a radiographic image having an appropriate image quality can be acquired efficiently.

1 is a diagram illustrating an overall configuration of a radiographic image capturing system according to an embodiment. (A) is a figure which shows the structure of an operation switch, (B) is a state which the button part was half-pressed, (C) is a figure explaining the state by which the button part was fully pressed. It is a perspective view which shows the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the XX line in FIG. It is a top view which shows the structure of the board | substrate of a radiographic imaging apparatus. It is an enlarged view which shows the structure of the radiation detection element, TFT, etc. which were formed in the small area | region on the board | substrate of FIG. It is sectional drawing which follows the YY line in FIG. It is a side view explaining the board | substrate with which COF, a PCB board | substrate, etc. were attached. It is a block diagram showing the equivalent circuit of a radiographic imaging apparatus. It is a block diagram showing the equivalent circuit about 1 pixel which comprises a detection part. 6 is a timing chart showing timings at which an on-voltage is applied to each scanning line in a reset mode, a charge accumulation mode, and a readout mode. It is a figure showing the flow of a radiographic imaging process and a dark image acquisition process. It is a figure which shows the generation speed of the dark charge which generate | occur | produces in a radiation detection element. When the accumulation time is long, the amount of dark charge generated and accumulated in the radiation detection element during the charge accumulation mode during radiographic imaging processing and the radiation detection element during the charge accumulation mode during dark image acquisition processing It is a figure for demonstrating the quantity of the dark electric charge which generate | occur | produces and accumulate | stores. When the accumulation time is short, the amount of dark charge generated and accumulated in the radiation detection element during the charge accumulation mode during radiographic imaging processing and the radiation detection element during the charge accumulation mode during dark image acquisition processing It is a figure for demonstrating the quantity of the dark electric charge which generate | occur | produces and accumulate | stores.

  Embodiments of a radiographic image capturing system and a radiographic image capturing apparatus according to the present invention will be described below with reference to the drawings.

  In the following description, the radiographic imaging device is a so-called indirect radiographic imaging device that includes a scintillator or the like and converts the irradiated radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electrical signal. As will be described, the present invention can also be applied to a direct radiographic imaging apparatus. Although the case where the radiographic image capturing apparatus is portable will be described, the present invention is also applicable to a radiographic image capturing apparatus formed integrally with a support base or the like.

[Radiation imaging system]
FIG. 1 is a diagram illustrating an overall configuration of a radiographic image capturing system according to the present embodiment.
For example, as shown in FIG. 1, the radiographic imaging system 50 includes an imaging room R1 that irradiates radiation and shoots a subject (part of a patient's imaging target) that is a part of a patient's body (not shown), and the imaging Adjacent to the room R1, an operator such as a radiographer is arranged in the front room R2 where various operations such as control of the start of irradiation of radiation to the subject are performed, and outside thereof.

  Specifically, as shown in FIG. 1, the radiographic image capturing system 50 performs predetermined processing on a radiographic image capturing apparatus 1 that performs a radiographic image capturing process and image data of a radiographic image captured by the radiographic image capturing apparatus 1. A console 58 that performs the image processing, and a radiation generator 55 that irradiates the radiation image capturing apparatus 1 with radiation.

  In the radiographing room R1, for example, a bucky device 51 in which the radiographic imaging device 1 can be loaded, a radiation source 52 including an X-ray tube (not shown) that generates radiation to irradiate a subject, and radiation for controlling the radiation source 52 A generator 55 and a wireless antenna 53 are provided, and a relay 54 that relays communication between the radiographic imaging device 1 and other devices such as the console 58 and the radiation generator 55 is provided.

In FIG. 1, when the portable radiographic imaging device 1 is used by being loaded into the cassette holding part 51a of the bucky device 51, or when it is used in a single state where it is not loaded into the bucky device 51, specifically, Although it is shown that the patient's hand as a subject is placed on the radiation incident surface R (see FIG. 3) and used on the upper surface side of the bucky device 51B for position photographing. The image capturing device 1 may be formed integrally with the bucky device 51, a support base or the like.
Here, when the portable radiographic image capturing apparatus 1 is used in a state where it is not loaded in the bucky device 51, the radiation incident surface R is disposed on the upper surface side of the bucky device 51 </ b> B for lying position imaging (see FIG. 3). In addition to placing and using the patient's hand as a subject on the subject, for example, the subject is placed on the upper surface side of a bed or the like provided in the imaging room R1, and the subject is placed on the radiation incident surface R (see FIG. 3). It is also possible to place a patient's hand or the like, or, for example, to insert between a patient's waist or legs lying on the bed and the bed.

  The repeater 54 is wired to the console 58 and the radiation generator 55 via a LAN (Local Area Network) cable or the like, and transmits information to the repeater 54 between the radiation image capturing apparatus 1 and the console 58. A converter (not shown) that converts a signal for LAN communication or the like into a signal for transmitting information to / from the radiation generator 55 and the reverse conversion is incorporated.

  The repeater 54 is connected to the Bucky device 51 by wire, and communication between the radiographic imaging device 1 loaded in the Bucky device 51 and other devices such as the console 58 and the radiation generating device 55 is performed. It is configured so that it can be performed in a wired manner via the repeater 54.

In FIG. 1, the radiographic image capturing apparatus 1, specifically, the radiographic image capturing apparatus 1 that is not loaded in the bucky apparatus 51, and the relay 54 are wirelessly connected, and the radiographic image capturing apparatus 1 and the console 58 or radiation Although the case where it has comprised so that communication between other apparatuses, such as the generator 55, can be performed by a radio | wireless system via the repeater 54 is shown, the radiographic imaging apparatus 1, the repeater 54, May be configured so that communication between the radiographic image capturing apparatus 1 and another apparatus can be performed in a wired manner via the repeater 54.
The radiographic image capturing apparatus 1 can be configured to be wirelessly connected to the repeater 54 even in a state where the radiographic image capturing apparatus 1 is loaded in the bucky device 51.

Further, FIG. 1 shows a case in which one of the standing-up shooting bucky device 51A and the standing-up shooting bucky device 51B is provided as the bucky device 51 in the shooting room R1. The number and type of the bucky devices 51 provided in the photographing room R1 are not particularly limited.
FIG. 1 shows a case in which one radiation source 52A associated with the bucky device 51 and one portable radiation source 52B are provided as the radiation source 52 in the imaging room R1. However, the number and type of radiation sources 52 provided in the imaging room R1 are not particularly limited.

[Radiation generator]
In the radiographing room R1, a radiation generator 55 for irradiating the radiographic imaging apparatus 1 with radiation is provided.
In the present embodiment, an operation console 57 of the radiation generator 55 is provided in the front room R2 adjacent to the imaging room R1, and an operator such as a radiologist is attached to the radiation generator 55 in the operation console 57. On the other hand, an exposure switch 56 is provided for operation when instructing the start of radiation irradiation or the like.

  For example, as shown in FIG. 2A, the exposure switch 56 includes a rod-shaped button portion 56a having a predetermined stroke, and a housing that supports the button portion 56a so as to be movable in the stroke direction indicated by an arrow S in the drawing. It is comprised with the body part 56b. The button part 56a of the exposure switch 56 includes, for example, a cylindrical part 56a1 protruding upward from the housing part 56b and a columnar part 56a2 protruding further upward from the inside thereof.

As shown in FIG. 2B, when the column portion 56a2 is pushed in the stroke direction S up to the upper end portion of the cylindrical portion 56a1 (that is, when a so-called half-press operation is performed), the exposure switch 56 An activation signal is transmitted to the radiation generator 55 via 57.
The radiation generator 55 is configured to place the radiation source 52 in a standby state by, for example, starting rotation of the anode of the X-ray tube of the radiation source 52 upon receiving this activation signal.

  Further, as shown in FIG. 2C, when both the cylindrical portion 56a1 and the column portion 56a2 of the exposure switch 56 are pushed to the upper end portion of the housing portion 56b (that is, when a so-called full pushing operation is performed). The exposure switch 56 is configured to transmit an irradiation signal to the radiation generator 55 via the console 57.

The radiation generating apparatus 55 is configured to transmit an irradiation start signal to the radiation image capturing apparatus 1 via the relay 54 when receiving the irradiation signal from the exposure switch 56.
The radiation generating device 55 is configured to irradiate radiation from the X-ray tube of the radiation source 52 when receiving the interlock release signal transmitted from the radiation image capturing device 1 via the repeater 54. Yes.

  Further, the radiation generating device 55 is operated by an operator such as a radiographer, for example, and operates the console 57 so that the radiation image capturing device 1 is appropriately irradiated with the radiation and the radiation source 52 position and radiation irradiation direction. Adjusting the aperture of the radiation source 52 so that the radiation is irradiated within a predetermined region of the radiation imaging apparatus 1, or adjusting the radiation source 52 so that an appropriate dose of radiation is irradiated. The radiation source 52 can be controlled in various ways such as. In addition, you may comprise so that operators, such as a radiographer, may perform these processes manually.

Further, the radiation generating device 55 receives the radiation source 52 when a predetermined time has elapsed from the start of radiation irradiation from the radiation source 52 or when a radiation irradiation end signal is transmitted from the radiation imaging apparatus 1. The irradiation of radiation from the radiation source 52 is stopped by stopping the X-ray tube.
Here, for example, the predetermined time is determined in advance by the operator such as a radiographer before the radiographic imaging, or by the operator such as the radiographer before the radiographic imaging. The irradiation time of the radiation corresponding to the imaging condition menu such as the imaging target region and the imaging direction.

[console]
For example, as shown in FIG. 1, the console 58 includes a display unit 58a composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), etc., a storage means 59 composed of an HDD (Hard Disk Drive), etc. A control unit 58b that controls the operation of each unit of the above, a communication unit 58c that is connected to the repeater 54 via a LAN cable or the like and communicates with other devices such as the radiographic imaging device 1, a keyboard, The computer includes an input unit 60 including a mouse or the like.

Although FIG. 1 shows the case where the console 58 is provided outside the imaging room R1 and the front room R2, the console 58 may be provided in the front room R2, for example.
1 shows the case where the storage means 59 is connected to the console 58, the storage means 59 may be built in the console 58.

When the communication unit 58c receives the image data of the radiographic image captured by the radiographic image capturing apparatus 1 from the radiographic image capturing apparatus 1 via the relay device 54, the control unit 58b of the console 58 decompresses the image data. In addition, predetermined image processing such as offset correction processing, gain correction processing, and automatic gradation processing is performed to create diagnostic image data.
Then, the control unit 58b of the console 58 displays a radiation image based on the diagnostic image data on the display unit 58a in accordance with an instruction from the input unit 60 or the like operated by the operator, or displays the diagnostic image data. Is output from the communication unit 58c or the like and transmitted to another device (not shown) such as an imager or a data management server.

  In the present embodiment, the offset correction process, the gain correction process, the automatic gradation process, and the like are described as being performed by the console 58. However, the offset correction process, the gain correction process, the automatic gradation process, and the like are performed using radiation. The image photographing apparatus 1 may perform this.

  In addition, for example, a preview image based on image data acquired by radiographic imaging is displayed on the console 58, and a function for changing the driving mode of the radiographic imaging device 1 between the wake mode and the sleep mode is provided. Or a function that allows an operator such as a radiographer to create or select radiographing order information representing the contents of radiographic imaging performed in the radiographing room R1. Is also possible and is configured accordingly.

[Radiation imaging equipment]
FIG. 3 is an external perspective view of the radiographic image capturing apparatus according to the present embodiment, and FIG. 4 is a cross-sectional view taken along line XX of FIG.
The radiographic image capturing apparatus 1 according to the present embodiment is configured as a portable (cassette type) apparatus in which a scintillator 3, a substrate 4, and the like are housed in a housing 2 as shown in FIGS. 3 and 4. .

The housing 2 is formed of a material such as a carbon plate or plastic that transmits radiation at least on a surface R (hereinafter referred to as “radiation incident surface R”) that is irradiated with radiation.
3 and 4 show a case in which the housing 2 is a so-called lunch box type formed by the frame plate 2A and the back plate 2B. However, the housing 2 is integrally formed in a rectangular tube shape. It is also possible to use a so-called monocoque type.

  Further, as shown in FIG. 3, in the present embodiment, for the replacement of the power switch 36, the indicator 37 composed of LEDs and the like, and the battery 41 (see FIG. 9 described later) on the side surface portion of the housing 2. A lid member 38 that can be opened and closed is disposed. In the present embodiment, the antenna device 39 is embedded in the side surface of the lid member 38.

Here, the antenna device 39 functions as a communication means for transmitting and receiving information such as data and signals to and from other devices such as the console 58 and the radiation generating device 55 via the repeater 54. .
When communication between the radiographic imaging apparatus 1 and another apparatus is performed by the wired system as described above, the radiographic imaging apparatus 1 includes a connector for connecting a LAN cable or the like as a communication unit. Provided.

  As shown in FIG. 4, a base 31 is disposed inside the housing 2 via a lead thin plate (not shown) on the lower side of the substrate 4, and an electronic component 32 and the like are disposed on the base 31. The PCB substrate 33, the buffer member 34, and the like are attached. In the present embodiment, a glass substrate 35 for protecting the substrate 4 and the scintillator 3 on the radiation incident surface R side is disposed.

  The scintillator 3 is arranged in a state of facing a detection unit P (described later) of the substrate 4. As the scintillator 3, for example, a scintillator 3 that has a phosphor as a main component and converts it into an electromagnetic wave having a wavelength of 300 to 800 nm, that is, an electromagnetic wave centered on visible light when it receives incident radiation, is used.

  In the present embodiment, the substrate 4 is formed of a glass substrate. As shown in FIG. 5, a plurality of scanning lines 5 and a plurality of signal lines are provided on a surface 4 a of the substrate 4 facing the scintillator 3. 6 are arranged so as to cross each other. A radiation detection element 7 is provided in each region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4.

  Thus, the entire region r in which the plurality of radiation detection elements 7 arranged in a two-dimensional manner are provided in each region r partitioned by the scanning line 5 and the signal line 6, that is, shown by a one-dot chain line in FIG. The region is a detection unit P.

In the present embodiment, a photodiode is used as the radiation detection element 7, but other than this, for example, a phototransistor or the like can also be used.
Each radiation detection element 7 is connected to a source electrode 8s of a TFT 8 serving as a switch means, as shown in FIG. 5 or FIG. 6 which is an enlarged view of FIG. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

The TFT 8 is turned on when an on-voltage is applied to the connected scanning line 5 by the scanning driving means 15 described later and applied to the gate electrode 8g via the scanning line 5, and the radiation detection element The electric charge accumulated in 7 is emitted from the radiation detection element 7 to the signal line 6.
The TFT 8 is turned off when an off voltage is applied to the connected scanning line 5 and applied to the gate electrode 8 g via the scanning line 5, and the charge from the radiation detection element 7 to the signal line 6 is turned off. Is stopped, and the charge generated in the radiation detection element 7 is held and accumulated in the radiation detection element 7.

  Here, the structure of the radiation detection element 7 and the TFT 8 in this embodiment will be briefly described with reference to a cross-sectional view shown in FIG. 7 is a cross-sectional view taken along line YY in FIG.

  A gate electrode 8g of a TFT 8 made of Al, Cr or the like is formed on the surface 4a of the substrate 4 so as to be integrally laminated with the scanning line 5, and silicon nitride (laminated on the gate electrode 8g and the surface 4a). An upper portion of the gate electrode 8g on the gate insulating layer 81 made of SiNx) is connected to the first electrode 74 of the radiation detecting element 7 through a semiconductor layer 82 made of hydrogenated amorphous silicon (a-Si) or the like. The source electrode 8s and the drain electrode 8d formed integrally with the signal line 6 are laminated.

  The source electrode 8s and the drain electrode 8d are divided by a first passivation layer 83 made of silicon nitride (SiNx) or the like, and the first passivation layer 83 covers the electrodes 8s and 8d from above. In addition, ohmic contact layers 84a and 84b formed in an n-type by doping hydrogenated amorphous silicon with a group VI element are stacked between the semiconductor layer 82 and the source electrode 8s and the drain electrode 8d, respectively. The TFT 8 is formed as described above.

  In the radiation detection element 7, an auxiliary electrode 72 is formed by laminating Al, Cr or the like on an insulating layer 71 formed integrally with the gate insulating layer 81 on the surface 4 a of the substrate 4. A first electrode 74 made of Al, Cr, Mo or the like is laminated on the auxiliary electrode 72 with an insulating layer 73 formed integrally with the first passivation layer 83 interposed therebetween. The first electrode 74 is connected to the source electrode 8 s of the TFT 8 through the hole H formed in the first passivation layer 83. Note that the auxiliary electrode 72 is not necessarily provided.

  On the first electrode 74, an n layer 75 formed in an n-type by doping a hydrogenated amorphous silicon with a group VI element, an i layer 76 which is a conversion layer formed of hydrogenated amorphous silicon, and a hydrogenated amorphous A p layer 77 formed by doping a group III element into silicon and forming a p-type layer is formed by laminating sequentially from below.

  And at the time of radiographic imaging, the radiation irradiated with respect to the radiographic imaging apparatus 1 injects from the radiation entrance surface R of the housing | casing 2, is converted into electromagnetic waves, such as visible light, with the scintillator 3, and the converted electromagnetic waves are illustrated. When irradiated from above, the electromagnetic wave reaches the i layer 76 of the radiation detection element 7, and electron-hole pairs are generated in the i layer 76. In this way, the radiation detection element 7 converts the electromagnetic waves irradiated from the scintillator 3 into electric charges (electron hole pairs).

  On the p layer 77, a second electrode 78 made of a transparent electrode such as ITO is laminated and formed so that the irradiated electromagnetic wave reaches the i layer 76 and the like. In the present embodiment, the radiation detection element 7 is formed as described above. The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed. Further, in the present embodiment, a case where a so-called pin-type radiation detection element formed by sequentially stacking the p layer 77, the i layer 76, and the n layer 75 as described above is used as the radiation detection element 7. However, it is not limited to this.

  A bias line 9 for applying a bias voltage to the radiation detection element 7 is connected to the upper surface of the second electrode 78 of the radiation detection element 7 via the second electrode 78. The second electrode 78 and the bias line 9 of the radiation detection element 7, the first electrode 74 extended to the TFT 8 side, the first passivation layer 83 of the TFT 8, that is, the upper surfaces of the radiation detection element 7 and the TFT 8 are The upper side is covered with a second passivation layer 79 made of silicon nitride (SiNx) or the like.

  As shown in FIGS. 5 and 6, in the present embodiment, one bias line 9 is connected to a plurality of radiation detection elements 7 arranged in rows, and each bias line 9 is connected to a signal line 6. Are arranged in parallel with each other. In addition, each bias line 9 is bound to one connection 10 at a position outside the detection portion P of the substrate 4.

  In the present embodiment, as shown in FIG. 5, each scanning line 5, each signal line 6, and connection 10 of the bias line 9 are input / output terminals (also referred to as pads) provided near the edge of the substrate 4. 11 is connected. As shown in FIG. 8, each input / output terminal 11 has a COF (Chip On Film) 12 in which a chip such as a gate IC 12a constituting a gate driver 15b of a scanning drive means 15 described later is incorporated on a film. They are connected via an anisotropic conductive adhesive material 13 such as an anisotropic conductive adhesive film or an anisotropic conductive paste.

  The COF 12 is routed to the back surface 4b side of the substrate 4 and connected to the PCB substrate 33 described above on the back surface 4b side. Thus, the board | substrate 4 part of the radiographic imaging apparatus 1 is formed. In FIG. 8, illustration of the electronic component 32 and the like is omitted.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 9 is a block diagram illustrating an equivalent circuit of the radiographic imaging apparatus 1 according to the present embodiment, and FIG. 10 is a block diagram illustrating an equivalent circuit for one pixel constituting the detection unit P.

As described above, each radiation detection element 7 of the detection unit P of the substrate 4 has the bias line 9 connected to the second electrode 78, and each bias line 9 is bound to the connection 10 to the bias power supply 14. It is connected. The bias power supply 14 applies a bias voltage to the second electrode 78 of each radiation detection element 7 via the connection 10 and each bias line 9.
The bias power supply 14 is connected to a control means 22 described later, and the control means 22 controls the bias voltage applied to each radiation detection element 7 from the bias power supply 14.

  As shown in FIGS. 9 and 10, in this embodiment, it can be understood that the bias line 9 is connected to the p-layer 77 side (see FIG. 7) of the radiation detection element 7 via the second electrode 78. In addition, the bias power supply 14 supplies a voltage equal to or lower than a voltage applied to the second electrode 78 of the radiation detection element 7 via the bias line 9 as a bias voltage on the first electrode 74 side of the radiation detection element 7 (that is, a so-called reverse bias voltage). ) Is applied.

  The first electrode 74 of each radiation detection element 7 is connected to the source electrode 8s (denoted as S in FIGS. 9 and 10) of the TFT 8, and the gate electrode 8g (FIGS. 9 and 10) of each TFT 8. Are respectively connected to the lines L1 to Lx of the scanning line 5 extending from the gate driver 15b of the scanning driving means 15 to be described later. Further, the drain electrode 8 d (denoted as D in FIGS. 9 and 10) of each TFT 8 is connected to each signal line 6.

  The scanning drive means 15 includes a power supply circuit 15a that supplies an on voltage and an off voltage to the gate driver 15b via the wiring 15c, and a voltage applied to each line L1 to Lx of the scanning line 5 between the on voltage and the off voltage. And a gate driver 15b for switching the TFT 8 between the on state and the off state.

  As shown in FIGS. 9 and 10, each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. In the present embodiment, the readout IC 16 is provided with one readout circuit 17 for each signal line 6.

  The readout circuit 17 includes an amplification circuit 18 and a correlated double sampling circuit 19. An analog multiplexer 21 and an A / D converter 20 are further provided in the reading IC 16. 9 and 10, the correlated double sampling circuit 19 is represented as CDS. In FIG. 10, the analog multiplexer 21 is omitted.

  In the present embodiment, the amplifier circuit 18 is formed of a charge amplifier circuit, and includes an operational amplifier 18a, a capacitor 18b and a charge reset switch 18c connected in parallel to the operational amplifier 18a. In addition, a power supply unit 18 d for supplying power to the amplifier circuit 18 is connected to the amplifier circuit 18.

The signal line 6 is connected to the inverting input terminal on the input side of the operational amplifier 18 a of the amplifier circuit 18, and the reference potential V ₀ is applied to the non-inverting input terminal on the input side of the amplifier circuit 18. . Note that the reference potential V ₀ is set to an appropriate value, and in this embodiment, for example, 0 [V] is applied.

The charge reset switch 18 c of the amplifier circuit 18 is connected to the control means 22, and is turned on / off by the control means 22.
When the TFT 8 is turned on while the charge reset switch 18c is turned off (that is, when a turn-on voltage is applied to the gate electrode 8g of the TFT 8 via the scanning line 5), each TFT 8 that is turned on is turned on. The charge accumulated from each radiation detection element 7 is discharged to the signal line 6 through the signal line 6, and the charge flows through the signal line 6 and flows into the capacitor 18 b of the amplifier circuit 18 and is accumulated.

  In the amplifier circuit 18, a voltage value corresponding to the amount of charge accumulated in the capacitor 18b is output from the output side of the operational amplifier 18a. In this way, the amplifier circuit 18 outputs a voltage value according to the amount of charge output from each radiation detection element 7 and converts the charge voltage.

When the amplifier circuit 18 is reset, when the charge reset switch 18c is turned on, the input side and the output side of the amplifier circuit 18 are short-circuited, and the charge accumulated in the capacitor 18b is discharged. Then, the discharged electric charge passes through the operational amplifier 18a from the output terminal side of the operational amplifier 18a, goes out from the non-inverting input terminal and is grounded, or flows out to the power supply unit 18d, so that the amplifier circuit 18 is reset. It has become.
Note that the amplifier circuit 18 may be configured to output a current in accordance with the charge output from the radiation detection element 7.

  A correlated double sampling circuit (CDS) 19 is connected to the output side of the amplifier circuit 18. In this embodiment, the correlated double sampling circuit 19 has a sample and hold function. The sample and hold function in the correlated double sampling circuit 19 is turned on / off by a pulse signal transmitted from the control means 22. To be controlled.

  Then, the control means 22 controls the amplification circuit 18 and the correlated double sampling circuit 19 in the process of reading image data from each radiation detection element 7 after radiographic imaging, and is emitted from each radiation detection element 7. The charge is converted into a charge voltage by the amplifier circuit 18, and the voltage value after the charge voltage conversion is sampled by the correlated double sampling circuit 19 and outputted to the downstream side as image data.

  The image data of each radiation detection element 7 output from the correlated double sampling circuit 19 is transmitted to the analog multiplexer 21 and sequentially transmitted from the analog multiplexer 21 to the A / D converter 20. Then, the A / D converter 20 sequentially converts the image data into digital values, which are output to the storage means 40 and sequentially stored.

  Further, as will be described later, the control unit 22 sequentially switches the lines L1 to Lx of the scanning line 5 to which the on-voltage is applied from the gate driver 15b of the scanning driving unit 15, and each time the switching is performed, as described above. Image data reading processing for reading image data from the radiation detection element 7 is performed.

The control means 22 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface connected to the bus, an FPGA (Field Programmable Gate Array), or the like (not shown). It is configured. It may be configured by a dedicated control circuit. And the control means 22 controls operation | movement etc. of each member of the radiographic imaging apparatus 1.
Further, as shown in FIG. 9 and the like, the control means 22 is connected to a storage means 40 composed of a DRAM (Dynamic RAM) or the like.

In the present embodiment, an antenna device 39 is connected to the control means 22.
Further, in the present embodiment, a battery 41 for supplying power to each functional unit such as the detection unit P, the scanning drive unit 15, the readout circuit 17, the storage unit 40, and the bias power supply 14 is connected to the control unit 22. Has been. The battery 41 is provided with a connection terminal 42 for connecting the charging device and the battery 41 when the battery 41 is charged by supplying power from the charging device (not shown).

  As described above, the control means 22 controls the bias power supply 14 to set a bias voltage to be applied to each radiation detection element 7 from the bias power supply 14, or the charge reset switch 18 c of the amplification circuit 18 of the readout circuit 17. The operation of each functional unit of the radiographic imaging apparatus 1 is controlled, such as controlling on / off or transmitting a pulse signal to the correlated double sampling circuit 19 to control on / off of the sample hold function. It is like that.

<Reset mode>
The control means 22 of the radiographic image capturing apparatus 1 acquires, as accurately as possible, charges, that is, image data, which are generated and accumulated in the radiation detecting elements 7 when the radiographic image capturing apparatus 1 is irradiated with radiation. Therefore, prior to radiographic imaging, a reset process is performed to reset each radiation detection element 7 by discharging excess charges remaining in each radiation detection element 7 from each radiation detection element 7. Has been.

Specifically, the control means 22 is configured to shift to a reset mode and start execution of a reset process for resetting each radiation detection element 7 by a predetermined trigger.
Here, in this embodiment, when a predetermined trigger is received as an imaging start instruction signal and an operator such as a radiographer operates the input unit 60 of the console 58 to instruct the start of radiographic imaging, the console 58 When the imaging start instruction signal is transmitted and the antenna device 39 receives the imaging start instruction signal, the control unit 22 will be described as transitioning to the reset mode. However, the present invention is not limited to this. The trigger is a depression of a switch such as the power switch 36 provided on the side surface portion of the radiographic image capturing apparatus 1, and an operator such as a radiographer switches the switch such as the power switch 36 provided on the side surface portion of the radiographic image capturing apparatus 1. It is also possible to make a transition to the reset mode when the user presses and instructs to start the radiographic image capturing process.

The reset of the radiation detection element 7 can be realized by applying an on-voltage to the scanning line 5 from the scanning drive unit 15 and releasing extra charge from the radiation detection element 7 to the signal line 6.
In the present embodiment, for example, as shown in FIG. 11, the on / off timing of each TFT 8, that is, the timing at which the on-voltage is applied from the gate driver 15 b of the scanning drive unit 15 to each of the lines L 1 to Lx of the scanning line 5. A method of resetting each radiation detection element 7 while sequentially switching is adopted, but the present invention is not limited to this. For example, an on-voltage is applied to a plurality of lines L of the scanning line 5 at the same time. A method of resetting the detection element 7 may be employed.

  In the present embodiment, as shown in FIG. 11, when performing the reset process, the lines L <b> 1 to Lx of the scanning line 5 are applied to the lines L <b> 1 to Lx at the same timing as the image data read process for reading the image data from each radiation detection element 7. Although the description will be made assuming that the voltage to be applied is switched between the on-voltage and the off-voltage, the on-voltage application timing and the on-voltage application time for each of the lines L1 to Lx of the scanning line 5 can be appropriately set.

<Charge accumulation mode>
Next, for example, as shown in FIG. 11, the control unit 22 turns off all the scanning lines 5, that is, all the lines L 1 to Lx of the scanning line 5 from the gate driver 15 b of the scanning driving unit 15 following the reset mode. By applying a voltage to turn off each TFT 8, it is configured to shift to a charge accumulation mode in which charges generated in each radiation detection element 7 by radiation irradiation are accumulated in each radiation detection element 7. Yes.

<Read mode>
Next, for example, as shown in FIG. 11, the control unit 22 applies the ON voltage from the scanning drive unit 15 to the scanning line 5 following the charge accumulation mode, thereby causing the radiation detection element 7 to apply the radiation to the signal line 6. The readout mode in which the image data readout process for reading out the image data from each radiation detection element 7 is performed by discharging the charges accumulated in the detection elements 7 and causing the readout circuit 17 to convert the emitted charges into image data. It is configured to transition.

  Specifically, the control unit 22 reads out while sequentially switching the timing of applying the on-voltage from the gate driver 15b of the scanning driving unit 15 to each of the lines L1 to Lx of the scanning line 5 in the same manner as in the reset process. The circuit 17 is caused to sequentially perform a read operation, and an image data read process for reading image data from each radiation detection element 7 is performed.

<Radiation image capturing process and dark image acquisition process>
Here, in the present embodiment, for example, as shown in FIG. 12, the radiographic image capturing apparatus 1 performs a radiographic image capturing process that captures a radiographic image, and the radiographic image is captured following the radiographic image capturing process. A dark image acquisition process for acquiring a correction dark image for correction is performed.

As described above, in each radiation detection element 7, so-called dark charges are constantly generated due to thermal excitation or the like of each radiation detection element 7 itself, and image data read processing for reading image data from each radiation detection element 7 is performed. In this case, dark charges are read out from each radiation detection element 7 in addition to the charges that are the true image data generated by the radiation irradiation, and the image data on which the offset due to the dark charges is superimposed is read out.
Therefore, in this embodiment, the radiographic image capturing apparatus 1 performs dark image acquisition processing subsequent to the radiographic image capturing processing in order to obtain true image data by subtracting the offset due to dark charge from the read image data. The radiation image capturing apparatus 1 is left in a state in which no radiation is applied to the radiation image capturing apparatus 1, and thereafter, offset data (dark image data) due to dark charges is read from each radiation detection element 7. ing.

  Specifically, for example, as illustrated in FIG. 12, the control unit 22 starts the radiographic image capturing process in response to an imaging start instruction signal from the console 58. First, a transition is made to the reset mode of the radiographic imaging process, and a reset process for resetting each radiation detection element 7 is performed.

Here, in this embodiment, the radiographic imaging device 1 has, as drive modes, a wake mode in which radiographic imaging can be performed and a sleep mode in which radiographic imaging cannot be performed.
Specifically, for example, when imaging is not performed for several minutes, the control unit 22 performs necessary functions such as the antenna device 39 from the wake mode in which power is supplied to each functional unit of the radiographic image capturing apparatus 1. For example, power is supplied only to the units, and the mode is switched to a sleep mode in which power is not supplied to other functional units such as functional units related to radiographic imaging such as the readout IC 16 and the radiation detection element 7.
That is, the radiographic image capturing apparatus 1 is configured to be able to suppress useless power consumption of the battery 41.

  Therefore, for example, as shown in FIG. 12, the radiographic image capturing apparatus 1 is in a standby state in a sleep mode (hereinafter referred to as a “sleep state”) or in a wake mode. While in the state (hereinafter referred to as “standby state”), the imaging start instruction signal from the console 58 is received.

When the imaging start instruction signal is received in the sleep state, the control unit 22 switches the drive mode of the radiographic image capturing apparatus 1 to a wake mode that supplies power to a functional unit related to radiographic image capturing, and the like. A transition is made to the reset mode of the radiographic imaging process to perform the reset process.
In addition, when the imaging start instruction signal is received in the standby state, the control unit 22 changes to the reset mode of the radiographic imaging process and resets while keeping the wake mode without switching the driving mode of the radiographic imaging apparatus 1. Process.

In the present embodiment, the console 58 is configured to transmit the accumulation time information together with the imaging start instruction signal to the radiation image capturing apparatus 1.
Then, the radiographic image capturing apparatus 1 determines the minimum reset time based on the accumulation time information, and until the elapsed time from the transition to the reset mode reaches the minimum reset time, the radiation image capturing apparatus 55 receives the radiographic image. The irradiation start signal transmitted to the imaging apparatus 1 is not accepted.

  The accumulation time information is information related to the accumulation time (that is, the time from the start to the end of the charge accumulation mode of the radiographic image capturing process). An imaging condition menu such as a determined irradiation time, an imaging target region and an imaging direction, which are determined in advance before radiographic imaging by an operator such as a radiographer.

  Specifically, for example, when an operator such as a radiologist operates the input unit 60 of the console 58 and inputs storage time information, the control unit 58b of the console 58 displays the input storage time information on the console 58. The communication unit 58 c is configured to transmit to the radiographic image capturing apparatus 1 via the repeater 54.

That is, the input unit 60 of the console 58 functions as an input unit for inputting storage time information regarding the storage time.
Further, the communication unit 58 c of the console 58 functions as a transmission unit that transmits the storage time information input by the input unit to the radiation image capturing apparatus 1.

  When the antenna device 39 of the radiographic image capturing apparatus 1 receives the accumulating time information from the console 58, the control unit 22 of the radiographic image capturing apparatus 1 determines the accumulating time based on the received accumulating time information and at the minimum. It is configured to determine a reset time.

Here, in the present embodiment, the charge accumulation mode of the radiographic imaging process is started at the same time or before the start of radiation irradiation from the X-ray tube of the radiation source 52, and the charge accumulation mode of the radiographic imaging process is started. It is assumed that the difference between the start timing and the start timing of radiation irradiation from the X-ray tube of the radiation source 52 is uniformly determined in advance.
In the present embodiment, the charge accumulation mode of the radiographic image capturing process is terminated at the same time as or after the radiation irradiation from the X-ray tube of the radiation source 52 is completed, and the charge accumulation mode of the radiographic image capturing process is terminated. It is assumed that a difference between the end timing and the end timing of radiation irradiation from the X-ray tube of the radiation source 52 is uniformly determined in advance.
Therefore, in this embodiment, since the accumulation time can be determined if the radiation irradiation time is known, when the radiation irradiation time is transmitted as the accumulation time information, the control means 22 transmits the transmitted radiation. The accumulation time is determined based on the irradiation time.

  In the present embodiment, an imaging condition menu list in which imaging condition menus such as “front of chest” and “side of head” are associated with an accumulation time is stored in advance in the storage unit 40 of the radiographic imaging apparatus 1. When the shooting condition menu is transmitted as the storage time information, the control unit 22 acquires the storage time corresponding to the transmitted shooting condition menu from the shooting condition menu list and transmits the storage time information. The storage time is determined based on the shooting condition menu that has been received.

  In the present embodiment, an imaging condition menu list in which an imaging condition menu and an accumulation time are associated with each other is stored in the radiographic image capturing apparatus 1, and the radiographic image capturing apparatus 1 is added to the transmitted imaging condition menu. The corresponding accumulation time is acquired from the imaging condition menu list, but the present invention is not limited to this. For example, the imaging condition menu in which the imaging condition menu and the irradiation time of radiation are associated with the console 58. The list is stored, and the console 58 acquires the radiation irradiation time corresponding to the imaging condition menu input by the operator from the imaging condition menu list, and the acquired radiation irradiation time is stored in the radiation image capturing apparatus 1. You may comprise so that it may transmit.

In the present embodiment, the radiographic image capturing apparatus 1 is configured to determine the accumulation time based on the transmitted accumulation time information. However, the present invention is not limited to this. For example, the console 58 The storage time may be determined based on the input storage time information, and the determined storage time may be transmitted to the radiographic imaging apparatus 1 as the storage time information.
Alternatively, devices other than the console 58, specifically, the radiation generator 55, the HIS (Hospital Information System, not shown), the RIS (Radiology Information System, not shown), etc. are used for the radiographic imaging device 1. The storage time may be notified.
In these cases, the radiographic imaging device 1 can set the accumulation time without determining the accumulation time based on the transmitted accumulation time information.

  In the present embodiment, the minimum reset time list in which the minimum reset time and the accumulation time are associated with each other is stored in advance in the storage unit 40 of the radiographic image capturing apparatus 1, and the control unit 22 determines the determined accumulation time. Is acquired from the minimum reset time list, and the minimum reset time is determined based on the transmitted storage time information.

  Here, the minimum reset time includes an offset error (that is, a difference obtained by subtracting an offset obtained as dark image data from an offset due to dark charges included in the image data) and a reset time (that is, reset of radiographic imaging processing). The time from the start to the end of the mode) is acquired for each accumulation time, and is the shortest reset time during which the offset error is less than or equal to a predetermined threshold, that is, the corrected image data This is the shortest time among the reset times when the image quality of the radiation image based on the above becomes an appropriate image quality.

  In the present embodiment, the list in which the minimum reset time and the accumulation time are associated is the minimum reset time list. However, the list is not limited to this, and the minimum reset time list is, for example, the minimum reset time. And a list in which radiation exposure time is associated, a list in which minimum reset time and imaging condition menu are associated, and the like. In this case, even if the accumulation time is not determined, the minimum reset time corresponding to the transmitted accumulation time information is obtained from the minimum reset time list, so that the minimum reset time is determined based on the transmitted accumulation time information. It becomes possible to decide.

Next, when the antenna device 39 receives the irradiation start signal from the radiation generator 55 after the elapsed time from the start of the reset mode reaches the minimum reset time determined based on the accumulation time information from the console 58, the control means 22 For example, as shown in FIG. 12, an interlock release signal is transmitted from the antenna device 39 to the radiation generating device 55 via the repeater 54, and at the same time, each radiation is shifted to the charge accumulation mode of the radiographic imaging process. Electric charges generated in the detection elements 7 are accumulated in each radiation detection element 7.
Therefore, even if the antenna device 39 receives the irradiation start signal from the radiation generator 55 before the elapsed time from the start of the reset mode reaches the minimum reset time determined based on the accumulation time information from the console 58, the control is performed. The means 22 is configured to continue the reset mode without transmitting an interlock release signal.

  Then, when the communication unit 55a of the radiation generation apparatus 55 receives the interlock release signal from the radiation image capturing apparatus 1, the radiation generation apparatus 55 starts irradiation of radiation from the X-ray tube of the radiation source 52.

  Next, when the elapsed time from the start of the charge accumulation mode reaches the accumulation time determined based on the accumulation time information from the console 58, the control means 22 performs, for example, as shown in FIG. Then, an image data reading process for reading out image data of the radiation image from each radiation detecting element 7 is performed.

  In the case of a configuration in which a radiation irradiation end signal is transmitted from the radiation image capturing apparatus 1 to the radiation generation apparatus 55, the control unit 22 receives radiation when the elapsed time from the start of the charge accumulation mode reaches the determined accumulation time. A transition is made to the readout mode of the image capturing process, and a radiation irradiation end signal is transmitted from the antenna device 39 to the radiation generator 55 via the relay 54.

  Next, when the image data reading process ends, the control unit 22 ends the radiographic image capturing process and starts the dark image acquisition process, for example, as shown in FIG. First, a transition is made to a reset mode for dark image acquisition processing, and reset processing for resetting each radiation detection element 7 is performed in the same manner as in the reset mode for radiographic image capturing processing.

Next, when the reset process is completed, that is, when a predetermined reset time has elapsed, for example, as shown in FIG. 12, the control unit 22 transitions to the charge accumulation mode of the dark image acquisition process, and the charge accumulation of the radiographic imaging process. In the same manner as in the mode, the charge generated in each radiation detection element 7 is accumulated in each radiation detection element 7.
At that time, while the radiographic image capturing apparatus 1 is in the charge accumulation mode of the dark image acquisition process, no radiation is irradiated from the radiation generating apparatus 55 to the radiographic image capturing apparatus 1. Only dark charges are stored in.

Next, when a predetermined waiting time elapses, the control unit 22 shifts to a dark image acquisition process readout mode, for example, as shown in FIG. Image data read processing for reading image data from the radiation detection element 7 is performed.
At this time, since the charge accumulated in each radiation detection element 7 in the charge accumulation mode of the dark image acquisition process is a dark charge, dark image data is read from each radiation detection element 7 in the read mode of the dark image acquisition process.

Here, in this embodiment, the predetermined waiting time, that is, the time from the start to the end of the charge accumulation mode of the dark image acquisition process, the time from the start to the end of the charge accumulation mode of the radiographic imaging process. Set the same time as.
In the present embodiment, the time from the start to the end of the readout mode of the radiation image capturing process, the time from the start to the end of the reset mode of the dark image acquisition process, and from the start to the end of the read mode of the dark image acquisition process It is assumed that the time is uniformly determined in advance regardless of the accumulation time.

Next, for example, as illustrated in FIG. 12, the control unit 22 uses the radiographic image data obtained by the radiographic image reading process readout mode and the dark image data obtained by the dark image acquisition process readout mode. The data is transmitted (transferred) from the antenna device 39 to another device such as the console 58 via the repeater 54.
As a result, the console 58 performs, for example, a subtraction process for subtracting the dark image data from the image data of the radiographic image, thereby performing an offset correction process on the image data of the radiographic image.

  Next, the operation of the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 according to the present embodiment will be described.

  First, when an operator such as a radiologist operates the input unit 60 of the console 58 to input accumulation time information and the like to instruct the start of radiographic image capturing, the control unit 58b of the console 58 relays from the communication unit 58c. An imaging start instruction signal is transmitted to the radiographic image capturing apparatus 1 through the device 54 together with the input accumulation time information.

  When the antenna device 39 receives the accumulation time information and the imaging start instruction signal from the console 58, the control unit 22 of the radiographic image capturing apparatus 1 shifts to the radiographic image capturing process and shifts to the reset mode. By applying an ON voltage to the scanning line 5, an extra charge remaining in each radiation detection element 7 is discharged from each radiation detection element 7 to the signal line 6 to reset each radiation detection element 7. Do.

  Here, when the antenna device 39 receives the accumulation time information or the imaging start instruction signal from the console 58 while the radiographic imaging device 1 is in the sleep state waiting in the sleep mode, the control means 22 Then, after switching the driving mode of the radiographic image capturing apparatus 1 to a wake mode that supplies power also to a function unit or the like related to radiographic image capturing, the mode is changed to the reset mode of the radiographic image capturing process to perform reset processing.

  For example, as shown in FIG. 13, dark charges generated by thermal excitation or the like due to heat of the radiation detection element 7 are not generated while power is not supplied to the functional unit related to radiographic imaging. This occurs immediately after the start of power supply to the functional unit related to shooting, and the generation speed gradually decreases and becomes constant over time.

  Therefore, since power is not supplied to the functional unit related to radiographic imaging in the sleep state, no dark charge is generated in the radiation detection element 7, but the radiographic imaging is performed in order to shift to the radiographic imaging processing. When the supply of power to the functional unit is started, dark charges are immediately generated in the radiation detection element 7. The generated dark charge is released during the reset mode of the radiographic imaging process.

  On the other hand, when the antenna device 39 receives the accumulation time information or the imaging start instruction signal from the console 58 while the radiographic imaging device 1 is in the standby state waiting in the wake mode, the control means 22 Without changing the drive mode of the radiographic image capturing apparatus 1, the wake mode is maintained and the reset process is performed by changing to the radiographic image capturing process reset mode.

  Therefore, in the standby state, since electric power is supplied to the functional unit related to radiographic imaging, dark charges are gradually generated and accumulated in the radiation detection element 7. The dark charges generated and accumulated in the standby state are gradually released during the reset mode of the radiographic image capturing process.

Further, the control means 22 of the radiographic image capturing apparatus 1 shifts to the reset mode of the radiographic image capturing process, determines the accumulation time based on the accumulation time information from the console 58, and determines the minimum reset time.
Specifically, the control unit 22 determines the accumulation time based on the accumulation time information from the console 58, and acquires the minimum reset time corresponding to the determined accumulation time from the minimum reset time list, thereby obtaining the console 58. The minimum reset time is determined based on the accumulation time information from

  When the elapsed time from the start of the reset mode of the radiographic imaging process reaches the minimum reset time determined based on the accumulation time information from the console 58, the control means 22 performs the console from the antenna device 39 via the relay 54. A preparation completion notice is transmitted to 58.

When the communication unit 58c receives the preparation completion notification from the radiographic imaging device 1, the control unit 58b of the console 58 displays “preparation complete” on the display unit 58a, and the preparation of the radiographic imaging device 1 is completed. An operator such as a radiologist is notified of the fact.
In the present embodiment, it is configured to notify that the preparation of the radiation imaging apparatus 1 is completed by displaying “ready” on the display unit 58a of the console 58, but the present invention is not limited thereto. For example, the preparation of the radiographic imaging apparatus 1 is completed by transmitting a preparation completion notification to the radiation generating apparatus 55 and displaying “ready” on the display unit (not shown) of the radiation generating apparatus 55. You may comprise so that it may alert | report.

Then, in response to the notification that the preparation of the radiographic imaging device 1 is completed, when an operator such as a radiographer presses the button portion 56 a of the exposure switch 56 halfway, the exposure switch 56 is connected via the console 57. The activation signal is transmitted to the radiation generator 55 from
When the activation signal is received, the radiation generator 55 puts the radiation source 52 into a standby state, for example, by starting rotation of the anode of the X-ray tube of the radiation source 52.

Subsequently, when the operator fully presses the button portion 56 a of the exposure switch 56, an irradiation signal is transmitted from the exposure switch 56 to the radiation generating device 55 via the console 57.
When the irradiation signal is received, the radiation generation device 55 (specifically, the control unit of the radiation generation device 55) transmits an irradiation start signal from the communication unit 55a to the radiation image capturing apparatus 1 via the relay 54.

When the antenna device 39 receives the irradiation start signal from the radiation generating device 55, the control means 22 of the radiographic image capturing device 1 transmits an interlock release signal from the antenna device 39 to the radiation generating device 55 via the relay 54. At the same time, a transition is made to the charge accumulation mode of the radiographic image capturing process, and the off-voltage is applied to all the scanning lines 5 from the scanning drive means 15 so that the charges generated in the respective radiation detection elements 7 by the radiation irradiation are changed. Accumulated in the radiation detection element 7.
On the other hand, when the communication unit 55 a receives the interlock release signal from the radiation image capturing apparatus 1, the control unit of the radiation generation apparatus 55 emits radiation from the X-ray tube of the radiation source 52 to the radiation image capturing apparatus 1. Irradiate.

Next, when the elapsed time from the start of the charge accumulation mode of the radiographic imaging process reaches the accumulation time determined based on the accumulation time information from the console 58, the control means 22 of the radiographic imaging apparatus 1 performs the radiographic imaging process. By transitioning to the reading mode and applying an ON voltage from the scanning driving means 15 to the scanning line 5, charges are discharged from the radiation detection elements 7 to the signal lines 6, and the discharged charges are transferred to the reading circuit 17 as image data. The image data reading process is performed by converting the image data.
On the other hand, when the elapsed time from the start of radiation irradiation by the X-ray tube of the radiation source 52 reaches a predetermined time, the control unit of the radiation generation device 55 performs irradiation of radiation from the X-ray tube of the radiation source 52. Stop.

In the case of a configuration in which a radiation irradiation end signal is transmitted from the radiation image capturing apparatus 1 to the radiation generating apparatus 55, the control means 22 of the radiation image capturing apparatus 1 determines that the elapsed time from the start of the charge accumulation mode is When the accumulation time determined on the basis of the accumulation time information from is reached, a transition is made to the readout mode of the radiographic imaging process, and a radiation irradiation end signal is transmitted from the antenna device 39 to the radiation generation device 55 via the relay 54. .
And the control part of the radiation generator 55 will stop irradiation of the radiation from the X-ray tube of the radiation source 52, if the communication part 55a receives the irradiation completion signal from the radiographic imaging apparatus 1. FIG.

  Next, when the image data reading process is completed, the control unit 22 of the radiographic image capturing apparatus 1 shifts to the dark image acquisition process, shifts to the reset mode, and applies the on-voltage to the scanning line 5 from the scanning driving unit 15. Thus, an extra charge remaining in each radiation detection element 7 is discharged from each radiation detection element 7 to the signal line 6 to reset the radiation detection element 7.

Next, when the reset process is completed, the control unit 22 of the radiographic image capturing apparatus 1 shifts to the charge accumulation mode of the dark image acquisition process, and applies the off voltage to all the scanning lines 5 from the scanning drive unit 15. Charges generated in each radiation detection element 7 due to radiation irradiation are accumulated in each radiation detection element 7.
At this time, since no radiation is irradiated from the X-ray tube of the radiation source 52 to the radiation image capturing apparatus 1, only dark charges are accumulated in each radiation detection element 7.

  Next, when the elapsed time from the start of the charge accumulation mode of the dark image acquisition process reaches a predetermined standby time, that is, the same accumulation time determined based on the accumulation time information from the console 58, the radiographic imaging device 1 The control means 22 makes a transition to the read mode of the dark image acquisition process, and applies an on-voltage from the scanning drive means 15 to the scanning line 5 to cause the radiation detection elements 7 to emit charges to the signal lines 6 to thereby read out the readout circuit. The image data reading process is performed by converting the emitted charges into image data.

Subsequently, when the image data reading process is completed, the control unit 22 of the radiographic image capturing apparatus 1 is obtained by the image data of the radiographic image obtained by the read mode of the radiographic image capturing process and the read mode of the dark image acquisition process. The dark image data is transferred from the antenna device 39 to another device such as the console 58 via the repeater 54.
When the communication unit 58c receives the radiographic image data or dark image data from the radiographic imaging device 1, the control unit 58b of the console 58 subtracts the dark image data from the radiographic image data, for example. By performing an offset correction process on the image data of the radiographic image, the predetermined image processing is performed on the image data of the radiographic image.

  Here, in order to accurately correct the image data, in order to obtain a more accurate correction dark image, the darkness generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process is acquired. It is preferable that the amount of charge and the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the dark image acquisition process are close. Therefore, in order to make these amounts closer, in this embodiment, the time from the start to the end of the charge accumulation mode of the radiographic image capturing process and the time from the start to the end of the charge accumulation mode of the dark image acquisition process are set. Match.

  However, when the irradiation start instruction signal is received from the console 58 while the radiation image capturing apparatus 1 is in the sleep state, the time from the start to the end of the charge accumulation mode of the radiation image capturing process and the dark image acquisition process The amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process and the dark image acquisition even if the time from the start to the end of the charge accumulation mode is made coincident There is a case where the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of processing greatly differs.

Specifically, in the radiographic imaging device 1, when an irradiation start instruction signal is received from the console 58 while in the sleep state waiting in the sleep mode, the drive mode is changed to a functional unit related to radiographic imaging, etc. Also, after switching to the wake mode for supplying power, the process proceeds to the radiographic imaging process.
At this time, as described above, dark charges are generated. For example, as shown in FIG. 13, the generation rate of dark charges gradually decreases and eventually becomes constant. When performing radiographic imaging processing before acquisition processing, transition to the charge accumulation mode of radiographic imaging processing before the dark charge generation rate becomes constant, that is, while the dark charge generation rate is gradually decreasing As a result, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the dark image acquisition process is generated in the radiation detection element 7 during the charge accumulation mode of the radiation image capturing process. The amount of dark charge that is accumulated increases.
This is, for example, the area of the hatched portion shown in FIGS. 14 and 15, specifically, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the dark image acquisition process. The area of the left hatched portion corresponding to the amount of dark charge generated and stored in the radiation detecting element 7 during the charge accumulation mode of the radiographic imaging process is larger than the area of the right hatched portion corresponding to It can be seen from the large.
For this reason, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process and generated in the radiation detection element 7 during the charge accumulation mode of the dark image acquisition process. In some cases, the amount of dark charge accumulated by the method differs greatly.

If the amount of dark charge generated and stored in the radiation detection element 7 differs greatly between the charge storage mode of the radiographic image capturing process and the charge storage mode of the dark image acquisition process, the dark data included in the image data The offset error, which is the difference obtained by subtracting the offset obtained as dark image data from the offset due to the charge, becomes large, and the image data cannot be corrected accurately, and there is a possibility that a radiographic image with an appropriate image quality cannot be obtained. is there.
However, since the dark charge generation speed will be constant over time, the dark charge generation speed becomes almost constant by setting a longer reset time, which is the time from the start to the end of the reset mode of the radiographic imaging process. If transition is made to the charge accumulation mode of the radiographic imaging process, the dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process and between the charge accumulation mode of the dark image acquisition process. It is possible that there is no difference in the amount of the error and the offset error becomes “0”.

  However, as described above, the offset error does not have to be “0”, and may be a value that is equal to or less than a predetermined threshold, that is, a value that can acquire a radiographic image with an appropriate image quality. Therefore, from the viewpoint of efficiently acquiring a radiographic image without taking time, it is not necessary to set a long reset time so that the dark charge generation rate becomes substantially constant.

  On the other hand, when the transition to the charge accumulation mode of the radiographic imaging process is performed while the generation rate of the dark charge is gradually decreasing, the charge accumulation mode of the radiographic imaging process and the dark image acquisition process are performed as described above. Since there is a difference in the amount of dark charge generated and accumulated between the charge accumulation modes, it is the time from the start to the end of the charge accumulation mode of the radiographic imaging process as in the conventional radiographic imaging apparatus. When the reset time is constant regardless of the accumulation time, there is a problem that the reset time is too long to efficiently acquire a radiographic image without taking too much time, or a radiographic image with adequate image quality with insufficient reset time There is a possibility that the problem that it is not possible to acquire the.

  Specifically, as in the present embodiment, the time from the end of the charge accumulation mode of the radiographic imaging process to the start of the charge accumulation mode of the dark image acquisition process is set to be constant regardless of the accumulation time. For example, as shown in FIGS. 14 and 15, the shorter the accumulation time (for example, in the case of FIG. 15), the charge accumulation mode start time ta of the radiographic imaging process and the charge accumulation of the dark image acquisition process As the mode start time tb becomes closer and the accumulation time becomes longer (for example, in the case of FIG. 14), the charge accumulation mode start time ta of the radiographic image capturing process and the charge accumulation mode start time tb of the dark image acquisition process Will be far away.

  Therefore, when transitioning to the charge accumulation mode of the radiographic imaging process while the dark charge generation rate is gradually decreasing, if the reset time is constant regardless of the accumulation time, for example, as shown in FIGS. Thus, as the accumulation time is shorter, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process and the radiation between the charge accumulation mode of the dark image acquisition process There is no large difference in the amount of dark charge generated and accumulated in the detection element 7, and the larger the accumulation time, the larger the difference often occurs.

That is, when transitioning to the charge accumulation mode of radiographic imaging processing while the dark charge generation rate is gradually decreasing, if the reset time is constant regardless of the accumulation time, the shorter the accumulation time, the more the offset error The possibility that the value becomes smaller and falls below the predetermined threshold increases, and the longer the accumulation time, the larger the possibility that the offset error becomes larger and exceeds the predetermined threshold.
Therefore, when transitioning to the charge accumulation mode of radiographic imaging processing while the dark charge generation rate is gradually decreasing, if the reset time is constant regardless of the accumulation time, the shorter the accumulation time, the shorter the reset time. There is a high possibility that a radiographic image will not be acquired efficiently without taking too much time. The longer the accumulation time, the shorter the reset time, and the acquisition of appropriate quality radiographic images. There is a high possibility that problems will occur.

  Therefore, as in the present embodiment, the minimum reset time is determined according to the storage time, and if the elapsed time from the start of the reset mode of the radiographic imaging process does not reach at least the determined minimum reset time, the next charge storage mode If the accumulation time is shorter, the shorter the accumulation time, the longer the reset time is, and the more difficult the radiographic image can be acquired without taking time. The longer the accumulation time, the shorter the reset time. It is possible to avoid the problem that a radiographic image with sufficient and appropriate image quality cannot be acquired.

  On the other hand, when the irradiation start instruction signal is received from the console 58 while the radiation image capturing apparatus 1 is in the standby state, the time from the start to the end of the charge accumulation mode of the radiation image capturing process, and the dark image acquisition process If the time from the start to the end of the charge accumulation mode is matched, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic imaging process and the dark image acquisition process In many cases, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode is substantially the same.

  Specifically, in the radiographic image capturing apparatus 1, when an irradiation start instruction signal is received from the console 58 while in a standby state waiting in the wake mode, the radiographic image capturing apparatus 1 already relates to radiographic image capturing before the reception. Since power is also supplied to the functional unit and the like, the process proceeds to the radiographic image capturing process while the wake mode is maintained. Therefore, when the irradiation start instruction signal is received from the console 58 during the standby state, the elapsed time from the start of the supply of power to the functional unit related to radiographic imaging is sufficiently long at the time of reception. Since the generation rate of dark charge is often constant, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode of the radiographic image capturing process, and the dark image acquisition process In many cases, the amount of dark charge generated and accumulated in the radiation detection element 7 during the charge accumulation mode is substantially the same.

  However, when the dark charge generated and accumulated in the radiation detection element 7 in the standby state is shifted to the next charge accumulation mode before all of the dark charges are released in the reset mode of the radiographic imaging process, the subsequent radiographic imaging process is read out. The dark charge generated and accumulated in the radiation detecting element 7 in the standby state in the read mode of the mode or dark charge acquisition processing is also read out. If the dark charge generated and accumulated in the radiation detection element 7 in the read mode is also read out, the offset obtained as the dark image data is subtracted from the offset due to the dark charge included in the image data. There is a risk that the offset error, which is the difference, becomes large, the image data cannot be corrected accurately, and a radiographic image with an appropriate image quality cannot be acquired.

In this case, after the reset time, which is the time from the start to the end of the reset mode of the radiographic imaging process, is set longer, all the dark charges generated and accumulated in the radiation detection element 7 in the standby state are released. If transition is made to the charge accumulation mode of the radiographic imaging process, there is no difference in the amount of dark charge read from the radiation detection element 7 between the readout mode of the radiographic imaging process and the readout mode of the dark image acquisition process, and the offset error is “ It can be “0”.
However, as described above, the offset error does not have to be “0”, and may be a value that is equal to or less than a predetermined threshold, that is, a value that can acquire a radiographic image with appropriate image quality.

On the other hand, when a transition is made to the charge accumulation mode of the radiographic imaging process before all the dark charges generated and accumulated in the radiation detection element 7 are released in the standby state, the readout mode of the radiographic imaging process is performed as described above. In other words, the dark charge generated and accumulated in the radiation detection element 7 in the standby state in the readout mode of the dark image acquisition process is read out. In this case, as the time from the start to the end of the charge accumulation mode is longer, various matters such as the possibility that excess charges such as dark charges remaining in the radiation detection element 7 are easily released in the next readout mode are affected. Thus, the longer the accumulation time, the greater the possibility that the offset error becomes larger and exceeds a predetermined threshold.
Therefore, when transitioning to the charge accumulation mode of the radiographic imaging process before all the dark charges generated and accumulated in the radiation detection element 7 in the standby state are released, if the reset time is constant regardless of the accumulation time, The shorter the accumulation time, the more likely it will be that the reset time is too long and the radiological image cannot be efficiently acquired without taking time. The longer the accumulation time, the less the reset time is appropriate. There is a high possibility that a problem that a radiographic image of a high quality cannot be acquired will occur.

  Therefore, as in the present embodiment, the minimum reset time is determined according to the storage time, and if the elapsed time from the start of the reset mode of the radiographic imaging process does not reach at least the determined minimum reset time, the next charge storage mode If the accumulation time is shorter, the shorter the accumulation time, the longer the reset time is, and the more difficult the radiographic image can be acquired without taking time. The longer the accumulation time, the shorter the reset time. It is possible to avoid the problem that a radiographic image with sufficient and appropriate image quality cannot be acquired.

  As described above, when the radiographic image capturing apparatus 1 is in the sleep state, the console 58 receives the accumulation time information or the irradiation start instruction signal from the console 58, and while the radiographic image capturing apparatus 1 is in the standby state. When the accumulation time information and the irradiation start instruction signal from 58 are received, the generation time of dark charge causing an offset error is different. Therefore, as the minimum reset time list, the list for the sleep state and the standby state are displayed. Both the list and the list may be stored. In this case, when the radiographic imaging apparatus 1 receives the accumulation time information or the irradiation start instruction signal from the console 58 while in the sleep state, the minimum reset time is determined with reference to the minimum reset time list for the sleep state. If the accumulation time information or the irradiation start instruction signal is received from the console 58 while the radiographic imaging apparatus 1 is in the standby state, the minimum reset time is determined by referring to the standby state minimum reset time list. It becomes possible to decide.

  Further, as described above, since dark charges are gradually generated and stored in the radiation detection element 7 in the standby state, they are generated and stored in the radiation detection element 7 in the standby state depending on the length of the standby state. The amount of dark charge is different. Accordingly, a plurality of types of lists corresponding to the length of the standby state may be stored as the minimum reset time list for the standby state, and the elapsed time from the start of the standby state may be measured. In this case, when the radiographic imaging apparatus 1 receives the accumulation time information and the irradiation start instruction signal from the console 58 while in the standby state, the length of the standby state in the minimum reset time list for the standby state. That is, the minimum reset time can be determined with reference to a list corresponding to the elapsed time from the start of the measured standby state.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of the present embodiment described above, the radiographic image capturing apparatus 1 acquires a correction dark image for correcting a radiographic image following the radiographic image capturing process. The control unit 22 of the radiographic image capturing apparatus 1 applies a turn-on voltage to the scanning line 5 from the scan driving unit 15 during the radiographic image capturing process. A reset process is performed to reset the radiation detection element 7 by discharging electric charges from the element 7, and when at least the minimum reset time has elapsed, an off voltage is applied from the scanning drive means 15 to all the scanning lines 5 to thereby cause the inside of the radiation detection element 7 When a transition is made to a charge accumulation mode in which charges are accumulated in the device and a predetermined accumulation time has elapsed, the scanning drive means 15 changes the scanning line 5 By applying a voltage, the charge is discharged from the radiation detecting element 7 and the read circuit 17 is converted to image data by converting the emitted charge into image data, thereby making a transition to a reading mode. ing. The minimum reset time is a time determined in advance according to the accumulation time.

That is, the minimum reset time required for the reset process performed during the radiographic image capturing process can be changed according to the accumulation time.
Therefore, there is a problem that occurs when the reset time is constant regardless of the accumulation time, specifically, a problem that the reset time is too long to efficiently acquire a radiographic image without taking time, and a reset time. Inadequate and the problem that it is not possible to acquire a radiographic image having an appropriate quality can be avoided, and a radiographic image having an appropriate image quality can be acquired efficiently.

  Further, according to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of the present embodiment described above, the console 58 is input by the input unit 60 for inputting the storage time information regarding the storage time and the input unit 60. A communication unit 58c that transmits the accumulated time information to the radiographic image capturing apparatus 1. The control unit 22 of the radiographic image capturing apparatus 1 determines a minimum reset time based on the accumulated time information transmitted by the communication unit 58c. Is configured to do.

  That is, the control means 22 of the radiographic imaging apparatus 1 sets the time determined based on the accumulation time information input by operating the input unit 60 of the console 58 by an operator such as a radiographer as the minimum reset time. Can do.

  By the way, the basic configurations of the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 according to the present embodiment are as described above. Various modifications will be described below.

[Modification 1]
In the above embodiment, the radiographic imaging device 1 is configured to determine the minimum reset time. Instead, the console 58 may be configured to determine the minimum reset time.

Specifically, for example, when a minimum reset time list or the like is stored in advance in the storage means 59 or the like of the console 58, and an operator such as a radiologist operates the input unit 60 of the console 58 to input the accumulated time information. The control unit 58b of the console 58 determines the minimum reset time based on the input storage time information, and the determined minimum reset time is determined from the communication unit 58c of the console 58 via the relay 54. It is also possible to configure to transmit to 1.
In this case, the control unit 22 of the radiographic image capturing apparatus 1 allows the antenna device 39 to output from the radiation generating apparatus 55 after the elapsed time from the reset mode start of the radiographic image capturing process reaches the minimum reset time from the console 58. When the irradiation start signal is received, an interlock release signal is transmitted from the antenna device 39 to the radiation generation device 55 via the relay 54, and at the same time, a transition is made to the charge accumulation mode of the radiographic imaging process, and each radiation detection element 7 It is possible to accumulate the charges generated in step 1 in each radiation detection element 7.

Further, the control unit 58b of the console 58 determines the storage time based on the input storage time information, and the determined storage time is transmitted from the communication unit 58c of the console 58 via the relay 54 to the radiation image capturing apparatus 1. It is also possible to configure to transmit to.
In this case, when the elapsed time from the start of the charge accumulation mode of the radiographic imaging process reaches the accumulation time from the console 58, the control unit 22 of the radiographic imaging apparatus 1 transitions to the readout mode of the radiographic imaging process. Thus, it is possible to perform an image data read process for reading the image data of the radiation image from each radiation detection element 7.

In the case of the first modification, the input unit 60 of the console 58 functions as an input unit for inputting storage time information related to the storage time.
Further, the control unit 58b of the console 58 functions as a determination unit that determines the minimum reset time based on the accumulation time information input by the input unit.
Further, the communication unit 58c of the console 58 functions as a transmission unit that transmits the minimum reset time determined by the determination unit to the radiographic image capturing apparatus 1.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of the first modification described above, the console 58 includes the input unit 60 for inputting the storage time information related to the storage time, and the storage input by the input unit 60. The control part 58b which determines minimum reset time based on time information, and the communication part 58c which transmits the minimum reset time determined by the control part 58b to the radiographic imaging apparatus 1 are provided.

  That is, the control means 22 of the radiographic imaging apparatus 1 sets the time determined by the console 58 based on the accumulation time information input by operating the input unit 60 of the console 58 by the operator such as a radiographer as the minimum reset time. Can be set.

[Modification 2]
In the above embodiment, the storage time information is transmitted from the console 58 to the radiation image capturing apparatus 1. Instead, the accumulation time information is transmitted from the radiation generation apparatus 55 to the radiation image capturing apparatus 1. It is also possible to configure.

Specifically, for example, when an operator such as a radiologist operates the console 57 of the radiation generating device 55 and inputs the accumulation time information, the radiation generating device 55 (specifically, the control unit of the radiation generating device 55). (Not shown) may be configured to transmit the input storage time information from the communication unit 55a of the radiation generation apparatus 55 to the radiographic imaging apparatus 1 via the relay 54.
In this case, the control means 22 of the radiographic imaging device 1 can determine the minimum reset time based on the accumulation time information from the radiation generator 55. Furthermore, when determining the minimum reset time based on the storage time information from the radiation generator 55, the storage time can be determined based on the input storage time information.

In the case of the modification 2, the console 57 of the radiation generating device 55 functions as an input unit for inputting storage time information regarding the storage time.
In addition, the communication unit 55 a of the radiation generation device 55 functions as a transmission unit that transmits the accumulation time information input by the input unit to the radiation image capturing apparatus 1.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of Modification 2 described above, the radiation generating apparatus 55 is input by the console 57 for inputting the accumulation time information regarding the accumulation time and the console 57. A communication unit 55a that transmits the accumulated time information to the radiographic image capturing apparatus 1. The control unit 22 of the radiographic image capturing apparatus 1 determines the minimum reset time based on the accumulative time information transmitted by the communication unit 55a. Is configured to do.

  That is, the control means 22 of the radiographic image capturing apparatus 1 sets the time determined based on the accumulation time information input by operating the console 57 of the radiation generating apparatus 55 by an operator such as a radiographer as the minimum reset time. can do.

[Modification 3]
In the above embodiment, the radiographic imaging device 1 is configured to determine the minimum reset time. Instead, the radiation generating device 55 may be configured to determine the minimum reset time.

Specifically, for example, a minimum reset time list or the like is stored in advance in a storage unit (not shown) or the like of the radiation generating device 55, and an operator such as a radiation engineer operates the console 57 of the radiation generating device 55. When the storage time information is input, the radiation generation device 55 (specifically, the control unit (not shown) of the radiation generation device 55) determines the minimum reset time based on the input storage time information, and It is also possible to configure so that the determined minimum reset time is transmitted from the communication unit 55a of the radiation generating apparatus 55 to the radiographic image capturing apparatus 1 via the relay 54.
In this case, the control unit 22 of the radiographic image capturing apparatus 1 allows the antenna device 39 to operate the radiation generating apparatus 55 after the elapsed time from the start of the reset mode of the radiographic image capturing process reaches the minimum reset time from the radiation generating apparatus 55. When the irradiation start signal is received from the antenna device 39, an interlock release signal is transmitted from the antenna device 39 to the radiation generating device 55 via the repeater 54, and the radiation detection element transits to the charge accumulation mode of the radiographic imaging processing. It becomes possible to accumulate the electric charges generated in each radiation detector 7.

Furthermore, the radiation generation device 55 (specifically, the control unit of the radiation generation device 55) determines an accumulation time based on the input accumulation time information, and the determined accumulation time is communicated to the radiation generation device 55. It is also possible to configure so as to transmit from the unit 55a to the radiation image capturing apparatus 1 via the repeater 54.
In this case, when the elapsed time from the start of the charge accumulation mode of the radiographic imaging process reaches the accumulation time from the radiation generation apparatus 55, the control unit 22 of the radiographic imaging apparatus 1 transitions to the readout mode of the radiographic imaging process. Thus, it is possible to perform image data reading processing for reading out image data of a radiation image from each radiation detection element 7.

In the case of the modification 3, the console 57 of the radiation generating device 55 functions as an input unit for inputting storage time information related to the storage time.
In addition, the radiation generator 55 (specifically, the control unit of the radiation generator 55) functions as a determination unit that determines the minimum reset time based on the storage time information input by the input unit.
In addition, the communication unit 55a of the radiation generation device 55 functions as a transmission unit that transmits the minimum reset time determined by the determination unit to the radiographic image capturing device 1.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of Modification 3 described above, the radiation generating apparatus 55 is input by the console 57 for inputting the storage time information regarding the storage time and the console 57. A control unit (not shown) that determines the minimum reset time based on the accumulated time information, and a communication unit 55a that transmits the minimum reset time determined by the control unit to the radiographic imaging apparatus 1.

  That is, the control means 22 of the radiographic image capturing apparatus 1 determines the minimum reset time by the radiation generation apparatus 55 based on the accumulation time information input by the operator such as a radiographer operating the console 57 of the radiation generation apparatus 55. Set time can be set.

[Modification 4]
In the above embodiment, the storage time information is input by operating the input unit 60 of the console 58, but instead, an operation unit (not shown) provided in the radiographic imaging apparatus 1 is operated. The storage time information can also be input.

Specifically, for example, an operation unit (not shown) for inputting accumulation time information or the like is provided on the side surface portion or the like of the radiographic image capturing apparatus 1, and an operator such as a radiographer operates the operation unit to store the operation time information. When the time information is input, the control unit 22 of the radiographic image capturing apparatus 1 may be configured to determine the minimum reset time based on the input storage time information.
Furthermore, in this case, when determining the minimum reset time based on the input storage time information, the storage time can be determined based on the input storage time information.

  In the case of the modification 4, the operation part provided in the side part of the radiographic imaging device 1 functions as an input unit for inputting accumulation time information regarding the accumulation time.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of Modification 4 described above, the radiographic image capturing apparatus 1 includes an operation unit for inputting accumulation time information related to the accumulation time, and the radiographic image capturing apparatus 1. The control means 22 is configured to determine the minimum reset time based on the storage time information input from the operation unit.

  That is, the control means 22 of the radiographic image capturing apparatus 1 is based on accumulation time information input by an operator such as a radiographer operating the operation unit provided on the side surface of the radiographic image capturing apparatus 1 as the minimum reset time. Can be set.

  Furthermore, it goes without saying that the present invention is not limited to the above-described embodiment and can be modified as appropriate.

DESCRIPTION OF SYMBOLS 1 Radiographic imaging device 5 Scanning line 6 Signal line 7 Radiation detection element 8 TFT (switch means)
DESCRIPTION OF SYMBOLS 15 Scan drive means 15a Power supply circuit 15b Gate driver 17 Read-out circuit 22 Control means 50 Radiation imaging system 55 Radiation generator (determination means)
55a Communication unit (transmission means)
57 Console (input means)
58 console 58b control unit (determining means)
58c Communication part (transmission means)
60 Input section (input means)
r region P detector

Claims (7)

A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
Subsequent to the radiographic image capturing process, it is configured to perform a dark image acquisition process for acquiring a correction dark image for correcting the radiographic image,
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Control means for controlling at least the scanning drive means and the readout circuit,
The control means includes
During the radiographic imaging process,
A reset process is performed to reset the radiation detection element by discharging the electric charge from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit,
When at least the minimum reset time elapses, the scan driving means transitions to a charge accumulation mode in which the charges are accumulated in the radiation detection elements by applying the off voltage to all the scanning lines.
When a predetermined accumulation time elapses, the charge is discharged from the radiation detection element by applying the on-voltage to the scanning line from the scanning driving unit, and the discharged charge is transferred to the image data by the readout circuit. The image data read processing is performed to make a transition to a read mode,
During the dark image acquisition process,
Perform the reset process,
When a predetermined reset time has elapsed, the state transitions to the charge accumulation mode and waits without being irradiated with the radiation,
It is configured to transition to the readout mode when a predetermined standby time has elapsed,
The minimum reset time is a time determined in advance according to the accumulation time. The console is
Input means for inputting storage time information relating to the storage time;
Transmission means for transmitting the storage time information input by the input means to the radiographic imaging device,
The radiographic imaging system according to claim 1, wherein the control unit determines the minimum reset time based on the accumulation time information transmitted by the transmission unit. The console is
Input means for inputting storage time information relating to the storage time;
Determining means for determining the minimum reset time based on the storage time information input by the input means;
The radiographic image capturing system according to claim 1, further comprising: a transmitting unit that transmits a minimum reset time determined by the determining unit to the radiographic image capturing apparatus. The radiation generator is
Input means for inputting storage time information relating to the storage time;
Transmission means for transmitting the storage time information input by the input means to the radiographic imaging device,
The radiographic imaging system according to claim 1, wherein the control unit determines the minimum reset time based on the accumulation time information transmitted by the transmission unit. The radiation generator is
Input means for inputting storage time information relating to the storage time;
Determining means for determining the minimum reset time based on the storage time information input by the input means;
The radiographic image capturing system according to claim 1, further comprising: a transmitting unit that transmits a minimum reset time determined by the determining unit to the radiographic image capturing apparatus. In a radiographic image capturing apparatus that performs radiographic image capturing processing for capturing a radiographic image,
Subsequent to the radiographic image capturing process, it is configured to perform a dark image acquisition process for acquiring a correction dark image for correcting the radiographic image,
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
By converting the by said charge emitted from the radiation detecting elements in images data, and a read circuit for performing image data reading processing from the radiation detecting device reads out the image data of the radiographic image,
Control means for controlling at least the scanning drive means and the readout circuit,
The control means includes
During the radiographic imaging process,
A reset process is performed to reset the radiation detection element by discharging the electric charge from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit,
When at least the minimum reset time elapses, the scan driving means transitions to a charge accumulation mode in which the charges are accumulated in the radiation detection elements by applying the off voltage to all the scanning lines.
When a predetermined accumulation time elapses, the charge is discharged from the radiation detection element by applying the on-voltage to the scanning line from the scanning driving unit, and the discharged charge is transferred to the image data by the readout circuit. The image data read processing is performed to make a transition to a read mode,
During the dark image acquisition process,
Perform the reset process,
When predetermined reset time has elapsed, it releases the transition to the charge storage mode rays are available at the state of not irradiated,
It is configured to transition to the readout mode when a predetermined standby time has elapsed,
The radiographic apparatus according to claim 1, wherein the minimum reset time is a time determined in advance according to the accumulation time. Input means for inputting storage time information relating to the storage time;
The radiographic imaging apparatus according to claim 6, wherein the control unit determines the minimum reset time based on accumulation time information input by the input unit.

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