JP2009297130A - Radiation detector, and radiation diagnosing system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detector capable of being used regardless of the type of a radiation source and capable of detecting a highly precise radiation image by accumulating no unnecessary charge. <P>SOLUTION: The radiation detector is equipped with a radiation data acquiring means, a switching means for outputting the radiation data acquired by the radiation data acquiring means, a data converting means for converting the outputted radiation data to electrical data, and an action control means for controlling the switching means and the data converting means. The action control means sets a parameter containing at least a radiation bombarding time and a radiation bombarding delay time and outputs a radiation bombarding signal to a system control means through a transmission-reception system. In the case where the photographing is required from the system control means, the action control means outputs a radiation bombardment permitting signal to the system control means so as to precede by the radiation bombarding delay time from the completion timing of the resetting of the whole surface of the radiation data acquiring means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiation detection apparatus that accumulates irradiated radiation for each position and outputs a signal corresponding to the accumulated intensity, and a radiation diagnostic system using the radiation detection apparatus.

Radiation diagnostic systems are used in various fields including, for example, medical diagnostic images and industrial nondestructive inspections. As a radiation image information detector (radiation detection device) that detects radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.) transmitted through a subject in a radiographic imaging device, Some use a flat panel detector (FPD) that converts to an electrical signal.
In a radiographic imaging apparatus using an FPD, a subject is irradiated with radiation from a radiation source, the radiation transmitted through the subject is converted into an electrical signal by the FPD, and an electrical signal corresponding to the image data of the subject is read out from the FPD. Is generated.

  Here, the radiological diagnosis system needs to synchronize the exposure operation of the radiation source and the detection operation of the radiation detection device in order to capture a radiographic image of the subject with high accuracy.

  Japanese Patent Application Laid-Open No. 2004-228688 discloses voltage detection means for detecting a voltage supplied to a high voltage circuit for supplying a high voltage to an X-ray tube, and an exposure indicating an X-ray generation period based on the output of the voltage detection circuit. An X-ray generation detection device having an exposure signal generating means for generating an emission signal, and when X-ray exposure is not performed, the charge accumulated in the image sensor is read out in the surroundings, and the thermal excitation and scattering X An X-ray imaging apparatus is described in which, when an exposure signal is detected, an image sensor reading operation is stopped and an electric charge generated by X-ray irradiation is accumulated when an exposure signal is detected so that extra charges due to lines and the like do not remain. ing.

  Patent Document 2 has detection means for detecting the start and end of radiation emission of a radiation source, and according to the detection result of the detection means, accumulation of electrical signals by the accumulation means and electricity accumulated by the readout means. A radiation imaging device for controlling signal readout is described.

  Patent Document 3 describes an X-ray imaging detector that predicts switching to an imaging mode by detecting a perspective projection X-ray pulse emitted from a radiation source.

  Patent Document 4 has two operation periods as an imaging operation period for capturing a radiographic image, an idling operation period before exposure of radiation and a reading operation period after exposure of radiation, There is described a radiation imaging apparatus that generates an exposure induction signal for a photographer during the idling operation period so that the photographer can operate the radiation generation switch at an appropriate timing immediately after the idling operation period.

JP 7-153590 A JP 2002-18942 A Japanese Patent Laid-Open No. 2003-307568 JP 2005-312949 A

The apparatus described in Patent Document 1 outputs an exposure signal from an X-ray source, and synchronizes with the exposure signal to store in an accumulation mode (that is, a mode in which radiation is converted into a signal such as an electric charge) and a reading mode ( That is, by starting the mode for reading the accumulated signal, etc., it becomes possible to start the accumulation of radiation without delay from exposure. However, the radiation detector performs a reset operation to remove the charge of the detection element during non-recording in order to detect the radiation appropriately. However, if the radiation detector is controlled based on the exposure signal from the X-ray source, the reset operation is performed. Is interrupted in the middle of the frame, which may adversely affect the image.
Thus, since it controls by the exposure signal output from an X-ray source, there exists a problem of receiving restrictions of timing, such as interrupting reset operation in the middle.
Further, since it is necessary to output an exposure signal from the X-ray source, there is a problem that the corresponding X-ray source is limited.

  Further, the apparatus described in Patent Document 2 detects the presence or absence of exposure by an exposure detection means provided on the radiation detection apparatus side, and shifts to the accumulation mode when it is detected that exposure has been performed. Similar to 1, it is possible to start the accumulation of radiation without delay from exposure. However, the device described in Patent Document 2 also has a problem that the reset mode operation is interrupted in the middle of the frame, which may adversely affect the image. For this reason, the apparatus described in Patent Document 2 also has a problem that it is subject to timing restrictions.

The apparatus described in Patent Document 3 also detects whether radiation is emitted from the radiation source by the exposure detection means provided on the radiation detection apparatus side, predicts the exposure timing from the result, and enters the accumulation mode. By shifting, it becomes possible to start accumulation of radiation without delay. However, the apparatus described in Patent Document 3 also has a problem that the reset mode operation is interrupted in the middle of the frame, which may adversely affect the image. For this reason, the apparatus described in Patent Document 3 also has a problem that it is subject to timing restrictions.
Moreover, since the apparatus described in Patent Document 3 is predictive control, there is a problem that it involves reliability. Furthermore, the apparatus described in Patent Document 3 needs to be a radiation source having a transmission mode before exposure.

Further, the apparatus described in Patent Document 4 can accumulate radiation without delay after the reset mode operation of the entire frame of the radiation detection apparatus is completed. However, since the user operates according to the guidance signal, there is a problem that there is a possibility of malfunction. In addition, when a long time elapses after induction, there is a problem that unnecessary charges accumulate in the radiation detection device and adversely affect the image.
Further, the apparatus described in Patent Document 4 has a problem that the operation becomes complicated because the user needs to operate the timing.

  An object of the present invention is to solve the problems based on the above-described prior art, and can be used regardless of the type of radiation source, and can detect a highly accurate radiation image without accumulating unnecessary charges. An object of the present invention is to provide a detection apparatus and a radiation diagnostic system using the same.

  In order to solve the above-described problems, the present invention provides a radiation detection apparatus that is disposed opposite to a radiation source and that can communicate with a system control apparatus that controls the operation of the radiation source, and that is responsive to the irradiated radiation. Radiation information acquisition means for acquiring the acquired information, switching means for outputting the information acquired by the radiation information acquisition means, information conversion means for converting the radiation information output via the switching means into electrical information, An operation control means for controlling the switching means and the information converting means; an information storing means for storing information obtained by the information converting means; and an output for outputting the information obtained by the information converting means to a system control means. Means, and a system control means and a transmission / reception means for transmitting / receiving information, the operation control means at least at the time of radiation exposure time and radiation exposure delay When the radiography exposure signal is output to the system control unit via the transmission / reception unit and an imaging request is made from the system control unit, the operation control unit acquires the radiation information. The radiation detection apparatus is characterized in that a radiation exposure permission signal is output to the system control means in advance of the radiation exposure delay time from the timing when the resetting of the entire surface of the means is completed.

  Here, the operation control means waits for a radiation exposure time after stopping the reset mode operation at the timing when the reset mode operation ends, and automatically controls the switching means and the information conversion means. It is preferable to start information acquisition.

In order to solve the above problems, the present invention is capable of communicating with the radiation detection apparatus according to any one of the above, a radiation source that irradiates radiation toward the radiation detection apparatus, the radiation detection apparatus, and the radiation source. And a system controller for controlling the operation of the radiation source.
Here, the radiation detection apparatus further includes radiation exposure detection means for detecting that radiation has been exposed to the radiation information acquisition means, and the system control means includes time measurement means for measuring time. The radiation detection device measures the time from the output of the radiation control signal by the time measurement means to the time when the radiation exposure detection means detects the radiation exposure at the time of calibration. The radiation exposure delay time is preferably set.

According to the radiation detection apparatus and the radiation diagnosis system of the present invention, it is possible to take a radiation image in a state where unnecessary charges remain in each part, and it is possible to detect a high-quality radiation image.
Further, according to the radiation detection apparatus of the present invention, it is possible to detect a high-quality radiation image using only the set values stored in the radiation detection apparatus without detecting whether or not radiation is emitted from the radiation source. it can.

  A radiation detection apparatus and a radiation diagnosis system using the same according to the present invention will be described in detail based on embodiments shown in the accompanying drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a radiation diagnostic system of the present invention using the radiation detection apparatus of the present invention.

  The radiation diagnostic system 10 shown in FIG. 1 includes a radiation source 12, a radiation source control circuit 14, a radiation detection device 16, an output unit 18, an imaging instruction unit 20, and a system controller (system control device) 22. . The radiation detection device 16 is disposed inside an examination table (not shown), and a subject to be measured (or an inspection target) is placed on an imaging table between the radiation source 12 and the radiation detection device 16. .

The radiation source 12 is a radiation irradiation mechanism that generates radiation, and irradiates the radiation detection device 16 with radiation. The radiation emitted from the radiation source 12 passes through the subject placed on the imaging table and enters the radiation detection device 16.
Here, as the radiation source 12, various radiation irradiation mechanisms used as a radiation source of a radiation diagnostic system can be used. In the present invention, X-rays, α rays, β rays, γ rays, electron beams, ultraviolet rays, and the like can be used as radiation.

  The radiation source control circuit 14 drives the radiation source 12 and controls the irradiation amount so that the radiation with the intensity set according to the imaging mode is irradiated for the set time.

The radiation detection apparatus 16 includes radiation information acquisition means 30, switching means 32, information conversion means 34, A / D conversion means 36, and detection control means 38.
The radiation detection device 16 detects the radiation that has passed through the subject by the radiation information acquisition means 30, and converts it into an electrical signal (detection signal, radiation image data) by the information conversion means 34. Thereafter, it is converted into digital radiation image data by the A / D conversion means, and is output from the detection control means 38 to the outside.

  The radiation information acquisition unit 30 is a panel that accumulates electric charges according to the amount of received radiation for each position of the matrix divided in two dimensions. The radiation information acquisition means 30 is composed of a photoconductive film such as amorphous selenium (a-Se) and a capacitor. When radiation such as X-rays is incident, the photoelectroconductive film emits electron-hole pairs (eh). Pair) is issued. The electron-hole pair is stored in the capacitor.

  The switching unit 32 includes a plurality of switching elements, and is provided for each line of the radiation image acquisition unit 30. The switching element is a TFT (Thin Film Transistor) or the like, and switches whether or not the charge accumulated in the radiation image acquisition unit 30 of the corresponding line is output to the information conversion unit 34.

The information conversion means 34 is a charge amplifier that converts charges into electrical information (analog voltage in the present embodiment), and includes, for example, an operational amplifier and a capacitor.
The information conversion means 34 turns on the switch of the switching means 32 and converts the electric charge accumulated in the radiation information acquisition means 30 into a voltage.
The information conversion unit 34 includes a multiplexer (MUX), selects a line in which the switching element is ON, and detects the charge supplied from the line from which the charge is output. When the matrix of the radiation information acquisition means 30 is divided into 256 channels (lines) × 12 systems, 3072 circuits are required if circuits corresponding to each matrix are prepared, but channels (lines) can be selected by a multiplexer. By doing so, the charge of each matrix can be detected by 12 circuits.
The analog voltage converted by the information conversion means 34 becomes analog image data.

  The A / D converter 36 converts the analog voltage image data output from the information converter 34 into digital signal image data.

  The detection control unit 38 includes an information storage unit 40 that stores the image data of the digital signal converted and output by the A / D conversion unit 36, and an operation control unit 42 that controls the operation of the switching unit 32 and the information conversion unit 34. And an output unit 44 that outputs the digital signal stored in the information storage unit 40 to the system controller 22 and a transmission / reception unit 46 that transmits and receives signals used for control with the system controller.

  The information storage unit 40 is a memory that stores the digital data output from the A / D conversion means 36. Here, as the memory, either a volatile memory or a nonvolatile memory can be used. The memory may have a capacity capable of storing one frame of image data (image data corresponding to one radiation image) or a capacity less than one frame of image data.

The operation control unit 42 controls the switching operation (that is, switching between ON / OFF) by the switching unit 32, the selection of the multiplexer by the information conversion unit 34, the output of the voltage, the switching between the photographing mode and the reset mode, and the like. It is a control circuit.
Here, the imaging mode refers to reading the electric charge accumulated in the radiation information acquisition means 30 by the radiation emitted from the radiation source 12, passing through the subject, and reaching the radiation information acquisition means 30, and acquiring a radiographic image of the subject. The reset mode is a mode in which a reset mode operation is performed. The reset mode operation is an idle reading operation that releases unnecessary residual charges of the switching unit 32 and the information conversion unit 34. Further, during the reset mode operation, the operations such as A / D conversion of the A / D conversion means 36 and charge amplifier driving of the information conversion means are basically stopped.
Further, the operation control unit 42 controls the timing for switching between the reset mode and the imaging mode based on the exposure delay time from when the radiation source 12 receives the exposure permission signal until when the exposure is actually started. . Here, the exposure delay time is a value detected by measurement or the like in advance.
Specifically, the operation control unit 42 outputs the exposure permission signal before the exposure delay time before the end of the reset mode operation. As a result, the reset mode operation ends immediately before radiation is emitted from the radiation source 12, and charges generated by radiation transmitted through the subject are accumulated in a state where there is substantially no residual charge in each part of the radiation detection device 30. Can be made. This point will be described in detail later together with an explanation of the operation of the radiation diagnostic system 10.
The operation control unit 42 performs the reset mode operation in units of one frame, and does not interrupt the reset mode operation in the middle of the frame.

  The output unit 44 outputs the image data stored in the information storage unit 40 to the system controller 22 in accordance with a signal from the system controller 22.

  The transmission / reception unit 46 transmits / receives signals used for control to / from the system controller 22. Here, as a signal transmitted / received between the transmission / reception unit 46 and the system controller 22, a command signal indicating that radiation source exposure is possible is transmitted from the transmission / reception unit 46 to the system controller 22 and set in the radiation detection apparatus 16. Command signals such as necessary parameters and modes and photographing requests are transmitted from the system controller 22 to the transmission / reception unit 46.

  The output unit 18 is a part that outputs image data after image processing supplied from the system controller 22. The output means 18 is, for example, a monitor that displays a radiation image on a screen, a printer that prints out a radiation image, a storage device that stores radiation image data, and the like.

  Here, in the radiological diagnosis system 10, predetermined imaging conditions are set in advance in addition to the manual imaging mode in which imaging conditions such as the intensity of radiation and irradiation time (irradiation amount) are manually set as imaging modes. A plurality of shooting modes are provided.

  The photographing instruction means 20 is a part that sets photographing conditions and a photographing mode and instructs photographing of the subject H. As the shooting instruction means 20, an input key for setting shooting conditions and a shooting mode and a shooting button of a two-step push type are used for shooting instructions. When the shooting button is pressed down to the first level, it is ready for shooting, and when it is pressed down to the second level, shooting starts. The shooting instruction means 20 outputs shooting instruction signals indicating shooting conditions, shooting modes, and shooting button states.

The system controller 22 includes a dedicated control circuit, a PC, and the like, and is connected to the radiation source control circuit 14, the radiation detection device 16, the output unit 18, and the imaging instruction unit 20.
The system controller 22 operates the radiation diagnostic system 10 in accordance with the imaging instruction signal supplied from the imaging instruction means 20, the control signal supplied from the radiation source control circuit 14, and the control signal supplied from the detection control means 38. It is a part to control. The system controller 22 includes, for example, control of radiation exposure by the radiation source 12, control of acquisition of radiation image data by the radiation detection device 16, image processing of radiation image data supplied from the radiation inspection device 16, and output unit 18. Control the output.
Here, the image processing performed by the system controller 22 on the radiation image data includes image processing such as step correction, contrast enhancement, and edge enhancement processing.
The radiation diagnostic system 10 is basically configured as described above.

Next, the operation of the radiation diagnostic system 10 will be described.
Here, FIG. 2 is a flowchart showing an example of the operation of the radiation diagnostic system 10, and FIG. 3 is a timing chart of the operation of each part of the radiation diagnostic system 10. Here, S10 to S28 described in the lower part of FIG. 3 correspond to the respective steps of the flowchart shown in FIG.

First, as shown in FIGS. 2 and 3, when the process is started and the radiation detector 16 is powered on, the radiation detector 16 is in an initial state and is in a NOP (Not Operation) state. .
Here, the NOP state is a state in which the switching means is not controlled (the reset mode does not operate) and no operation is performed on the radiation detection apparatus 16. However, since the reset signal for the information conversion means 34 remains stationary while being active, the information conversion means 34 is always in a reset state. Here, the reset state of the information conversion means 34 is a state in which the unnecessarily accumulated charge is released to the GND by short-circuiting the capacitor unit that converts the charge into voltage.

Here, the operation control unit 42 of the present embodiment has three types of command registers (controller command in FIG. 3), status register (control unit state in FIG. 3), and parameter register (parameter application in FIG. 3). Has a register. The operation control unit 42 performs a control operation in accordance with a signal set in the instruction register. In addition, the status register discloses the implementation status and results of various operations, and the system controller 22 can detect the status of the radiation detection device 16 by reading the status register via the transmission / reception unit 46. Become.
In addition, the operation control unit 42 refers to the parameter set in the parameter register, and performs the shooting mode operation and the reset mode operation. Here, the parameter register has at least two or more surfaces (referred to as A surface, B surface,...), And in this embodiment, the A surface is a register dedicated to the reset mode operation. The parameter application change is performed when the operation mode shifts, and the initial state is application of the A side (dedicated to the reset mode).

When the preparation for system operation is completed, the system controller 22 writes a reset mode operation request in the instruction register (or command setting) of the operation control unit 42.
While the reset mode operation request signal is set, the operation control unit 42 continues to perform the reset mode operation unless a request with higher priority than the reset mode operation (such as shooting) is set (step S10).
Further, the switching means 32 generates an internal signal indicating that the driving for one frame is completed when the driving for one frame is completed regardless of the modes such as the reset mode driving and the imaging driving. The switching unit 32 generates an internal signal indicating that the driving for one frame is completed, and then performs internal detection to determine whether the imaging mode driving or the same mode (that is, the reset mode operation) is repeated. When no other mode operation request is received during the reset mode operation, the reset mode operation is automatically continued after the completion of the 1-frame reset mode operation. Note that the reset mode operation (normal version) of this embodiment operates at a period of about 46 msec per frame.

When the reset mode operation is performed and the camera can enter the shooting operation, the system controller 22 detects whether there is a shooting request (step S12).
If there is no photographing request, the reset operation in step S10 is continued.

When the system controller 22 detects that an imaging request is input from the imaging instruction means 22 by the user (examiner), the system controller 22 transmits an imaging request command to the operation control unit 42.
When the operation control unit 42 receives the imaging request command, the reset mode operation in progress at that time is completed for one frame (that is, until the reset mode operation for the region corresponding to the entire surface of the radiation information acquisition unit 30 is completed). ) Wait (step S14).

Thereafter, when the reset mode operation for one frame is completed (that is, the reset mode operation is completed for one frame), an exposure permission signal is transmitted as a command after a predetermined time has elapsed after the start of the next reset mode operation (step S16). ).
Specifically, first, the operation control unit 42 determines and controls the control cycle of each unit using an internal counter in both the photographing mode and the reset mode. The operation control unit 42 calculates the count value (hereinafter referred to as “standby count value”) of the internal counter corresponding to the timing for transmitting the exposure permission signal from the set exposure delay time (tpshot).
Next, when the count of the internal counter reaches the standby count value (n1 in this embodiment), the operation control unit 42 transmits an exposure permission signal to the system controller 22 as a command. Here, the exposure permission signal is in an output (Active state) during a time (tpshot + tshot) obtained by adding the exposure delay time and the exposure time.
When the exposure permission signal is transmitted to the system controller 22, the system controller 22 transmits processing information to the radiation source control circuit 14 based on the exposure permission signal, and causes the radiation source 12 to emit radiation.
Here, as described above, when the exposure permission signal is transmitted to the system controller 22, the last reset mode operation before imaging is in progress, but the exposure permission signal is transmitted in consideration of the exposure delay time. Therefore, when the radiation is actually emitted from the radiation source 12, the radiation detection device 16 has completed the reset mode operation for one frame and has shifted from the reset mode operation to the imaging mode.
The time lag from when the user (inspection engineer) requests exposure to when the exposure operation is actually started is 46 msec in the reset mode operation 1 frame even in the worst case, rather than the user experiencing the time lag. It's a short enough time.

Here, the operation control unit 42 switches the parameter register from the A-side (dedicated to the reset mode) to the shooting mode after shifting to the shooting mode. The parameter register may be configured to have an A-side / B-side configuration and shift to the B-side when a shooting request is made. May be applied. In this embodiment, four surfaces A to D are prepared, and the B surface is designated in the shooting mode. In addition, although it does not explain about the case where this embodiment, C surface, and D surface are used, what is necessary is just to select according to mode, for example, if C surface and D surface are used in the case of the photography mode from which conditions differ. Good.
When the shooting mode parameter is applied, the operation control unit 42 initializes the switching unit 32 internally. This is because the parameter to be applied next is different from the reset mode operation parameter, so that the operation failure is solved.

  Next, after the radiation exposure from the radiation source 12 is started (that is, after the reset mode is stopped), the operation control unit 42 waits for the radiation exposure time (tshot) (step S18). Here, the radiation exposure time is set with reference to the parameter contents. At this time, the radiation detection device 16 stops the operation of the TFT which is the switching means 32, and the information conversion means 34 and the A / D conversion means 36 continue to be reset.

While waiting, it is detected whether the exposure time has elapsed (step S20).
When it is detected in step S20 that the radiation exposure time has elapsed, the operation control unit 42 transmits an image data read command for driving the switching means 32 and the information exchanging means 34 to read data, and the radiation Data is read from the information acquisition means 30. (Step S22). Note that the time from when the exposure permission signal is transmitted to when the image data read command is transmitted is the sum of the exposure delay time and the exposure time (tpshot + tshot).

Specifically, first, when the detection control means 38 recognizes the end of the radiation exposure time, it transmits a one-frame data start command (hereinafter referred to as “VD command”) to the system controller 22. When receiving the VD command, the system controller 22 transmits a one-line data request command to the detection control means 38.
The operation control unit 42 of the detection control unit 38 starts control of the switching unit 32, the information conversion unit 34, and the A / D conversion unit 36 when the data read mode is entered. By sequentially turning on the switching elements of the switching means 32, the charge of the corresponding pixel is output to the information conversion means 34 of the corresponding channel. The information exchanging means 34 selects the position of the signal output from the multiplexer and outputs it as an analog voltage signal at the corresponding position.
The A / D conversion unit 36 converts the analog voltage signal output from the information exchange unit 34 into digital electrical information (hereinafter referred to as “pixel data”), and outputs the digital electrical information to the detection control unit 38.

  The detection control unit 38 accumulates and rearranges the pixel data output from the A / D conversion unit 36 and stores it in the information storage unit 40 as a group of lines. The information storage unit 40 of this embodiment uses an SRAM arranged in an FPGA (Filed Programmable Gate Array) that is in charge of control of the operation control unit 42. In addition, the information storage unit 40 of the present embodiment has a size that can store data of 10 lines or less.

Next, it is determined whether a one-line image request command is transmitted from the system controller 22 to the detection control means 38 (step S24).
If the one-line image request command has not been transmitted, step S24 is repeated.
When a one-line image request command is transmitted to the detection control means 38, image data for one line is transmitted from the output unit 44 to the system controller 22 (step S26).
Specifically, when a one-line image data request command is transmitted from the system controller 22 to the detection control unit 38, the detection control unit 38 confirms the state of the information storage unit 40, and data is stored in the information storage unit 40. If stored, the corresponding image data is read out. The detection control unit 38 converts the read data into serial data, and transmits the data to the system controller 22 from the output unit 44 in units of packets for each line.
Next, the system controller 22 determines whether image data for all lines has been received (step S28).
When it is determined that the image data for all the lines has not been received, that is, when the image data for one frame has not been received, the system controller 22 receives the image data for one line, and then the system controller 22 The next one-line data request command is transmitted to the detection control means 38, and the process proceeds to step S24.
If it is determined that the image data for all lines has been received, for example, if the system controller 22 determines that the image data has been received for a predetermined number of lines (only one frame), thereafter, the image to the operation control unit 42 is displayed. The data request request command is not transmitted, and the processing corresponding to one shooting is terminated.
As described above, the system controller 22 and the detection control unit 28 repeat steps S24 to S28, and the detection control unit 38 transmits image data for one frame to the system controller 22.
The detection control unit 38 stops the control when the control is completed for the predetermined number of lines described in the parameters. Note that it is preferable to always reset the information conversion means 34 as before photographing. Further, the detection control means 38 switches the parameter register from the photographing mode (B surface) to the reset mode (A surface). Also, an internal signal for the end of one frame is generated, and the location where the shooting mode is operating is initialized in the operation control unit 42.

In addition, the system controller 22 performs image processing such as step correction, contrast enhancement, and edge enhancement on image data for one frame.
Further, the image data after the image processing is output by the output means 18. Specifically, when the output means is a monitor, it is displayed on the monitor, and when the output means is a printer, it is printed out. The user diagnoses the subject using the output radiation image.

Further, the operation control unit 42 shifts to the reset mode operation again after the photographing mode is completed. If continuous shooting with a short frame rate is required, such as energy subtraction shooting or fluoroscopic observation, the next shooting may be started without shifting to the reset mode operation.
In addition, when some control (having higher priority than the reset mode) is required after shooting, the control may be performed instead of the reset mode operation.
In addition, when the command for stopping the reset mode operation is transmitted from the system controller 22 to the operation control unit 42 and the operation control unit 42 receives the corresponding command (or the register for resetting the mode operation stop is written in the operation control unit 42). At any time (for example, even if the reset mode operation is not completed for one frame), the reset mode operation may be stopped.
The radiological image diagnosis system 10 captures a radiographic image of a subject as described above, and uses the captured radiographic image for diagnosis of the subject.

As described above, according to the radiation detection device 16 and the radiological image diagnosis system 10, the reset mode operation is performed while taking into account the time from when the exposure permission signal is transmitted to when the radiation is actually emitted from the radiation source. The exposure permission signal is output at the end, and the reset mode operation for one frame is completed immediately before the radiation reaches the radiation information acquisition means, so that the residual charge of each part of the radiation detection device 16 can be reduced. Therefore, it is possible to capture a radiation image with higher accuracy.
Further, since the operator only has to input the exposure request, the burden on the operator can be reduced. Further, since the time lag from when the exposure request is input to when the exposure permission signal is output is short, the burden on the operator and the subject is small, and the frame rate is hardly lowered.

In addition, since the radiation detection device 16 can set the exposure delay time, it can cope with various radiation sources having different exposure delay times.
Further, the radiation detection device 16 does not electrically connect / control the radiation detection device 16 and the radiation source (and its control circuit), and the system controller 22 confirms the state of the radiation detection device 16 (or a command). Radiation exposure may be performed at a timing based on the received result. Thus, since it can control based on the exposure delay time and parameter setting means of the radiation source to be used, the radiation detection apparatus 16 can be used for any radiation source or diagnostic system. Further, the radiation detection device 16 can perform control without detecting whether or not radiation has been emitted from the radiation source.

Here, the detection control unit 38 may transmit the acquired data to the system controller 22 as it is, or performs image processing such as filter processing as much as possible in the detection control unit 38 and then stores it again in the memory. Then, it may be transmitted to the system controller 22 again.
Alternatively, the image data may be transmitted to the system controller 22 without being stored again in the memory after image processing.

In the radiation diagnostic system 10 described above, it is assumed that the exposure delay time of the radiation source 12 is known and the exposure delay time is set in the detection control means of the radiation detection system. The invention is not limited to this.
FIG. 4 is a block diagram showing a schematic configuration of another embodiment of the radiation diagnostic system of the present invention using the radiation detection apparatus of the present invention.
The radiation diagnostic system 60 shown in FIG. 4 has the same configuration as that of the radiation diagnostic system 10 shown in FIG. 1 except that the radiation detection device 66 and the time measurement unit 68 are provided in the radiation detection device 62. Since they are the same, the same parts are denoted by the same reference numerals and description thereof is omitted, and the points peculiar to the radiation diagnostic system 60 will be described in detail below.

  The radiation diagnostic system 60 includes a radiation source 12, a radiation source control circuit 14, a radiation detection device 62, an output unit 18, an imaging instruction unit 20, and a system controller 22. Here, the radiation source 12, the radiation source control circuit 14, the output unit 18, the imaging instruction unit 20, and the system controller 22 are the same as the respective units of the radiation diagnostic system 10 shown in FIG. Is omitted.

  The radiation detection device 62 includes radiation information acquisition means 30, switching means 32, information conversion means 34, A / D conversion means 36, detection control means 64, and radiation exposure detection means 64. Here, since the radiation information acquisition means 30, the switching means 32, the information conversion means 34, and the A / D conversion means 36 are the same as each part of the radiation detection apparatus 16, the description is abbreviate | omitted.

The radiation exposure detection means 64 is a radiation detection element that detects radiation, and is arranged on the radiation source 12 side where the radiation is emitted. The radiation exposure detection means 64 transmits to the detection control means 64 the timing at which the radiation emitted from the radiation source 12 is sensed.
Here, the radiation exposure detection means 64 is preferably arranged close to the radiation information acquisition means 30, and is preferably arranged on the same plane as the radiation sensing surface of the radiation information acquisition means 30. By arranging the radiation exposure detection means 64 in the vicinity of or on the same plane as the radiation information acquisition means 30, the timing at which the radiation emitted from the radiation source 12 reaches the radiation information acquisition means 30, and the radiation exposure detection The timing to reach the means 64 can be made substantially simultaneously, and the timing at which the radiation reaches the radiation information acquisition means 30 can be detected more accurately.

The detection control unit 64 includes an information storage unit 40, an operation control unit 42, an output unit 44, a transmission / reception unit 46, and a time measurement unit 68. Here, the information storage unit 40, the operation control unit 42, the output unit 44, and the transmission / reception unit 46 are the same as the respective units of the detection control unit 38, and thus description thereof is omitted.
The time measurement unit 68 measures the time from when the operation control unit 42 outputs the exposure permission signal to when the radiation exposure detection unit 66 detects the radiation.

Such a radiation diagnostic system 60 outputs an exposure permission signal from the transmission / reception unit 46 of the detection control means 64 and emits radiation from the radiation source 12 at the time of calibration, and the radiation source radiation exposure detection means 66 and time measurement. The unit 68 measures the time from when the exposure permission signal is output until the radiation exposure detection means 66 detects the radiation, and sets the measurement result as the exposure delay time.
Thus, providing the radiation detection device 62 with a function for detecting the exposure delay time increases the cost of the device and complicates the device configuration. However, if the exposure delay time is unknown or the same model is used. When the individual difference is large, it is possible to cope with a case where the exposure delay time that has been known changes with time.
In addition, it is possible to cope with a change with time and an error with a set value, and control can be performed using a more accurate exposure delay time, so that a higher quality radiographic image can be taken (detected).

  The radiation detection apparatus and the radiation diagnostic system using the radiation detection apparatus according to the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiment, and various types can be made without departing from the gist of the present invention. Improvements and changes may be made.

  Here, in the above embodiment, the radiation detection device 16 is a direct radiation detection device that directly converts radiation into electric charge and generates a detection signal. However, the present invention is not limited to this, and for example, radiation The present invention can also be used for an indirect radiation detection apparatus that converts light once and then converts the converted light into an electrical signal to generate a detection signal. Also, an optical reading type radiation detection apparatus that detects radiation by a method different from the known direct method and indirect method proposed by the present applicant in Japanese Patent Application No. 2007-218816 and generates a detection signal can be used. .

  Here, the indirect radiation detection apparatus includes, for example, a scintillator layer made of a phosphor such as “CsI: Tl”, a photodiode, a capacitor, and a TFT. For example, when radiation is incident, the scintillator layer emits light (fluoresce). Light emitted by the scintillator layer is photoelectrically converted by a photodiode and accumulated in a capacitor, and the electric charge accumulated in the capacitor is read out as an electrical signal through the TFT.

  Furthermore, an optical reading type radiation detection apparatus can be summarized as follows: a recording photoconductive layer that generates conductivity when irradiated with radiation (recording light) and exhibits conductivity, and a charge pair when irradiated with reading light. A reading photoconductive layer that is generated and exhibits conductivity, a substrate that is transparent to reading light, and the like are laminated in this order. Further, the optical reading type radiation detection apparatus is provided with a line light source for sequentially irradiating the substrate side with reading light for one line when the accumulated electric charge is read out.

  In the optical reading type radiation detection apparatus, when line-shaped reading light is irradiated from a line light source, the portion irradiated with the reading light in the image information recorded as the latent image polar charge accumulated in the power storage unit The image information for one line recorded in is read as an electric signal of a level corresponding to the amount of latent image polarity charge for each pixel through the transparent linear electrode. By performing this process for all lines, image information for one screen is read as image data.

  In any of the above cases, it is necessary to perform a reset mode operation for removing unnecessary charges from a reading circuit such as a TFT before acquiring radiation information. Therefore, even when the radiation detection apparatus of the above method is used, a higher quality radiation image can be taken by performing control based on the exposure delay time.

It is a block diagram which shows schematic structure of one Embodiment of the radiation diagnostic system of this invention using the radiation detection apparatus of this invention. It is a flowchart which shows an example of operation | movement of a radiation diagnostic system. It is a timing chart of operation of each part of a radiation diagnostic system. It is a block diagram which shows schematic structure of other embodiment of the radiation diagnostic system of this invention using the radiation detection apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radiation diagnostic system 12 Radiation source 14 Radiation source control circuit 16 Radiation detection apparatus 18 Output means 20 Imaging instruction means 22 System controller 30 Radiation information acquisition means 32 Switching means 34 Information conversion means 36 A / D conversion means 38, 64 Detection control means 40 Information Storage Unit 42 Operation Control Unit 44 Output Unit 46 Transmission / Reception Unit 66 Radiation Exposure Detection Means 68 Time Measurement Unit

Claims (4)

A radiation detection device disposed opposite to the radiation source and capable of communicating with a system control device that controls the operation of the radiation source,
Radiation information acquisition means for acquiring information according to the irradiated radiation;
Switching means for outputting information acquired by the radiation information acquisition means;
Information conversion means for converting the radiation information output via the switching means into electrical information;
Operation control means for controlling the switching means and the information conversion means;
Information storage means for storing the information obtained by the information conversion means;
Output means for outputting information obtained by the information conversion means to a system control means;
A system control means and a transmission / reception means for transmitting / receiving information;
The operation control means sets parameters including at least a radiation exposure time and a radiation exposure delay time, and outputs a radiation exposure signal to the system control means via the transmission / reception means,
When an imaging request is made from the system control device, the operation control unit controls the system to send a radiation exposure permission signal ahead of the timing when the reset of the entire surface of the radiation information acquisition unit ends by a radiation exposure delay time. A radiation detection apparatus that outputs to a means.   The operation control means waits for the radiation exposure time after stopping the reset mode operation at the timing when the reset mode operation ends one frame, and automatically controls the switching means and the information conversion means to acquire information. The radiation detection apparatus according to claim 1, which starts. The radiation detection apparatus according to claim 1 or 2,
A radiation source that emits radiation toward the radiation detection device;
A radiation diagnostic system comprising: a system control device capable of communicating with the radiation detection device and the radiation source and controlling an operation of the radiation source. The radiation detection apparatus further includes radiation exposure detection means for detecting that radiation has been exposed to the radiation information acquisition means,
The system control means has time measuring means for measuring time,
The radiation detection apparatus measures a time from the output of the radiation control signal by the time measurement means to the time when the radiation exposure detection means detects the radiation exposure at the time of calibration, and the measured time is measured by the radiation exposure. The radiation diagnostic system according to claim 3, wherein the radiation diagnostic system is set as a shooting delay time.

Images