JP2009195612A - Radiographic imaging apparatus - Google Patents

Abstract

A radiographic imaging apparatus capable of detecting the occurrence of vibration without separately using means such as a vibration detection sensor.
A radiation image capturing apparatus irradiates a subject with radiation from a radiation source, detects radiation transmitted through the subject with a flat panel radiation detector, and generates a radiation image in which the subject is photographed. is there. The vibration detecting unit detects whether or not vibration exceeding a preset vibration allowable range has occurred based on a change in the output signal of the radiation detector.
[Selection] Figure 1

Description

  The present invention relates to a radiographic imaging apparatus that irradiates a subject with radiation, detects the radiation transmitted through the subject, converts the radiation into an electrical signal, and generates a radiation image based on the converted electrical signal.

  Radiographic imaging devices are used in various fields including, for example, medical diagnostic images and industrial nondestructive inspection. As a radiation detector for detecting radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.) transmitted through a subject in a radiographic imaging apparatus, a flat panel that converts radiation into electrical signals at present There is a type using a flat panel detector (FPD).

  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. However, if the imaging apparatus vibrates during imaging, there is a problem that the effect of the vibration (image defect) appears in the captured radiographic image, and the image quality of the captured radiographic image is degraded.

  Here, as a prior art document relevant to the present invention, for example, Patent Document 1 can be exemplified.

  In Patent Document 1, a detection unit (for example, a vibration detection sensor that detects a vibration amount of the apparatus main body) that is provided in the apparatus main body and detects a state where the apparatus main body is installed, and a detection signal detected by the detection unit are disclosed. A control unit that determines whether or not it is within the range of installation conditions of the apparatus and outputs an output signal based on the detection signal; and an output signal from the control unit is input, and a detection result by the detection unit There is disclosed an image forming apparatus including confirmation means for confirming the above.

JP 2004-104611 A

  Conventionally, it is known to detect the vibration of an imaging apparatus using a vibration detection sensor and display the presence / absence of vibration and the amount of vibration, but no countermeasures against image defects due to vibration have been made. Therefore, it is necessary for the user (operator) to determine whether or not to take a picture again by viewing the display of the presence / absence of vibration and the vibration amount. This may lead to misdiagnosis in the case of a medical diagnostic image, and there is a problem that damage to a patient is great.

The first object of the present invention is to provide a radiographic imaging apparatus capable of solving the problems of the prior art and separately detecting the occurrence of vibration without using means such as a vibration detection sensor. There is.
In addition to the first object described above, the second object of the present invention is to control the operation of the photographing device or to instruct the user whether or not re-photographing is necessary when the occurrence of vibration is detected. An object of the present invention is to provide a radiographic imaging apparatus that can perform the above-described process.

In order to achieve the above object, the present invention irradiates a subject with radiation from a radiation source, detects the radiation transmitted through the subject with a flat panel radiation detector, and obtains a radiographic image obtained by photographing the subject. A radiographic imaging device to generate,
Provided is a radiographic imaging device comprising a vibration detection unit that detects whether or not vibration exceeding a preset vibration allowable range has occurred based on a change in an output signal of the radiation detector. To do.

The present invention also provides a radiographic imaging apparatus that irradiates a subject with radiation from a radiation source, detects radiation transmitted through the subject with a flat panel radiation detector, and generates a radiographic image in which the subject is imaged. Because
An imaging data processing unit that performs data processing including A / D conversion on the output signal of the radiation detector;
A radiographic imaging apparatus comprising: a vibration detection unit that detects whether or not vibration exceeding a preset vibration allowable range has occurred based on a change in an output signal of the imaging data processing unit. provide.

Here, a control unit for controlling the operation of the radiographic imaging apparatus is provided,
When the vibration detection unit detects that the vibration exceeding the vibration allowable range has occurred before the radiation irradiation, the control unit is configured to reduce the vibration to a level not exceeding the vibration allowable range. It is preferable to control so that the irradiation is stopped and the subject is not photographed.

A control unit for controlling the operation of the radiographic imaging apparatus; and a printer for printing out the radiographic image.
The control unit stops the radiation irradiation when the vibration detection unit detects that the vibration exceeding the vibration allowable range has occurred during the radiation irradiation before the radiation irradiation is completed. It is preferable to control so that the radiation image for which the radiation irradiation has been stopped is not printed out from the printer.

In addition, a control unit that controls the operation of the radiographic apparatus, and a monitor that displays the radiographic image,
The control unit instructs the subject to be re-photographed when the vibration detection unit detects that a vibration exceeding the allowable vibration range is generated during the radiation irradiation after the radiation irradiation is completed. It is preferable to control to display a message to be displayed on the monitor.

  In this invention, a vibration detection part detects whether the vibration exceeding a vibration allowable range has generate | occur | produced based on the output signal of a radiation detector. Therefore, a separate means such as a vibration detection sensor is unnecessary, and the cost can be reduced accordingly.

  When it is detected that vibration exceeding the allowable vibration range has occurred before radiation irradiation (before photographing), the subject cannot be photographed. Accordingly, it is possible to prevent radiographic images that may cause image defects due to the occurrence of vibration exceeding the allowable vibration range. Therefore, it is possible to prevent unnecessary radiation irradiation and printout of radiation images that may have image defects.

  In addition, when it is detected before the radiation irradiation is completed that the vibration exceeding the allowable vibration range is generated during the radiation irradiation (during the imaging), the imaging is stopped before the imaging is completed. As a result, it is possible to cancel the print output of the radiation image in which an image defect may have occurred due to the occurrence of vibration exceeding the allowable vibration range. Since unnecessary print output can be prevented, the cost can be reduced accordingly.

  Further, when it is detected after the radiation irradiation is completed (after imaging) that the vibration exceeding the allowable vibration range is generated, a message instructing re-imaging is displayed on the monitor. As a result, the user of the photographing apparatus can know that it is necessary to perform photographing again. By performing re-imaging, a radiographic image free from image defects due to vibration can be obtained. For example, in the case of a medical diagnostic image, misdiagnosis can be prevented.

  Hereinafter, a radiographic imaging apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a block diagram of an embodiment showing a configuration of a radiographic image capturing apparatus of the present invention. The radiographic imaging apparatus 10 shown in the figure irradiates a subject (subject) H with radiation, detects the radiation transmitted through the subject H, converts it to an electrical signal corresponding to image data, and converts the converted electrical signal. Based on the above, a radiographic image in which the subject H is captured is generated. The imaging device 10 includes an imaging unit 12, an imaging data processing unit 14, an image processing unit 16, a vibration detection unit 17, an output unit 18, an imaging instruction unit 20, and a control unit 22.

  The imaging unit 12 is a part that shoots the subject H by irradiating the subject H with radiation and detecting the radiation transmitted through the subject H. The imaging unit 12 outputs data (analog data) of a radiographic image obtained by imaging the subject H. Details of the photographing unit 12 will be described later.

  Subsequently, the imaging data processing unit 14 is a part that performs data processing such as A / D (analog / digital) conversion on the radiation image data supplied from the imaging unit 12. The radiographic image data (digital data) after data processing is output from the imaging data processing unit 14.

  The image processing unit 16 is a part that performs image processing such as offset correction and afterimage correction on the radiographic image data after data processing supplied from the imaging data processing unit 14. The image processing unit 16 is configured by a program (software) operating on a computer, dedicated hardware, or a combination of both. The image processing unit 16 outputs the radiation image data after the image processing.

  Based on the change in the output signal of the radiation detector (FPD 32, which will be described later) of the imaging unit 12, the vibration detection unit 17 detects vibration exceeding the preset allowable vibration range (vibration of the imaging apparatus 10, more precisely, imaging). This is a part for detecting whether or not the vibration of the part 12 has occurred. The vibration detection unit 17 outputs a vibration detection signal indicating whether or not vibration exceeding the allowable vibration range has occurred.

  Based on the output signal of the charge amplifier of the FPD 32, the vibration detector 17 detects whether or not vibration exceeding the allowable vibration range has occurred. Therefore, a separate means such as a vibration detection sensor is unnecessary, and the cost can be reduced accordingly.

  The output unit 18 is a part that outputs radiographic image data after image processing supplied from the image processing unit 16. The output unit 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. Various messages including a message corresponding to the vibration detection signal are displayed on the monitor of the output unit 18.

  Here, in the photographing apparatus 10, predetermined photographing conditions are set in advance in addition to a manual photographing mode in which photographing conditions such as radiation intensity and irradiation time (amount of irradiation) are manually set as photographing modes. Multiple shooting modes are provided.

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

  The control unit 22 is a part that controls the operation of the imaging apparatus 10 in accordance with the imaging instruction signal supplied from the imaging instruction unit 20. For example, the control unit 22 performs shooting control in the shooting unit 12, image processing control in the image processing unit 16, and output control in the output unit 18. Moreover, although mentioned later for details, the control part 22 controls the operation | movement in each site | part of the imaging device 10 based on the vibration detection signal supplied from the vibration detection part 17. FIG.

  Next, the photographing unit 12 will be described.

  The imaging unit 12 includes an irradiation control unit 24, a radiation source 26, an imaging table 28, and a radiation detection unit 30.

  The irradiation control unit 24 drives the radiation source 26 to control the irradiation amount so that the radiation with the intensity set according to the imaging mode is irradiated for the set time. Radiation emitted from the radiation source 26 passes through the subject H on the imaging table 28 and enters the radiation detection unit 30.

  The radiation detection unit 30 detects the radiation transmitted through the subject H with the FPD 32 and converts it into an electrical signal (radiation image data). The radiation detection unit 30 outputs data (analog data) of a radiation image obtained by photographing the subject H. The FPD 32 can be either a direct FPD that directly converts radiation into electric charges, or an indirect FPD that converts radiation once into light and then converts the converted light into an electrical signal.

  The direct type FPD includes a photoconductive film such as amorphous selenium, a capacitor, a TFT (Thin Film Transistor) as a switch element, and the like. For example, when radiation such as X-rays is incident, electron-hole pairs (e-h pairs) are emitted from the photoconductive film. The electron-hole pair is accumulated in the capacitor, and the electric charge accumulated in the capacitor is read out as an electric signal through the TFT.

  On the other hand, an indirect FPD is composed of a scintillator layer made of a phosphor, a photodiode, a capacitor, a TFT, and the like. For example, when radiation such as “CsI: Tl” is incident, the scintillator layer emits light (fluoresces). 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.

  In addition, in Japanese Patent Application No. 2007-218816, the present applicant has proposed an optical reading type FPD that detects radiation by a method different from the known direct method and indirect method. As the FPD 32, this optical reading type FPD can also be used.

  In general, an optical reading type FPD generates a charge pair when it is irradiated with radiation (recording light) and exhibits conductivity. When it is irradiated with a reading light, it generates a charge pair and becomes conductive. The photoconductive layer for reading exhibiting the property, the substrate having transparency to the reading light, and the like are provided in this order. Further, the optical reading type FPD is provided with a line light source for sequentially irradiating the substrate side with reading light for one line when the accumulated charge is read out.

  In an optical reading type FPD, when line-shaped reading light is irradiated from a line light source, recording is performed on a portion irradiated with reading light in image information recorded as a latent image polarity charge accumulated in a power storage unit. The image information for one line is read out as an electrical signal having 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.

  Although not shown, the radiation source 26 and the radiation detection unit 30 are reciprocated along the longitudinal direction (left and right direction in FIG. 1) of the imaging table 28 for, for example, long imaging. It is configured as possible. On the other hand, you may comprise the imaging stand 28 so that a movement is possible.

  Next, the FPD 32 will be described.

  FIG. 2 is a circuit diagram showing the configuration of the FPD shown in FIG. The FPD 32 is a direct radiation detector, and is configured by arranging a plurality of pixels (pixels) 34 having the configuration shown in FIG. 2 in an array. Further, in the same figure, an equivalent circuit 36 of a data line that propagates image data (analog signal) read from each pixel 34 of the FPD 32 and image data propagated through the data line are amplified and output. A charge amplifier 38 is shown.

  Each pixel 34 of the FPD 32 includes a photoconductive film 40, a capacitor (Cs) 42, and a TFT 44. An electrode 46 is provided on the entire upper surface of the photoconductive film 40, and an electrode 48 is provided corresponding to each pixel 34 on the lower surface. The electrode 46 on the upper surface of the photoconductive film 40 is connected to the ground via a voltage source (Vh) 50, and the electrode 48 on the lower surface is connected to the ground via a capacitor 42. The TFT 44 is connected between a data line and a node connecting the electrode 48 on the other surface of the photoconductive film 40 and the capacitor 42.

  The data line equivalent circuit 36 includes a resistance element (Rd) 52 and a capacitor (Cd) 54. The resistance element 52 is connected between the TFT 44 and the operational amplifier 56, and the capacitor 54 is connected between a node connecting the TFT 44 and the resistance element 52 and the ground. The image data read from each pixel 34 of the FPD 32 is propagated to the charge amplifier 38 after being delayed by a time determined by the resistance value of the resistance element 52 and the capacitance value of the capacitor 54 by the data line.

  The charge amplifier 38 includes an operational amplifier 56 and a capacitor 58. The negative terminal of the operational amplifier 38 is connected to the data line, and the positive terminal is connected to the ground. The capacitor 58 is connected between the negative terminal of the operational amplifier 56 and the output terminal. The output signal of the charge amplifier 38 (the output signal of the operational amplifier 56) is supplied to the photographing data processing unit 14.

  As shown in FIG. 2, for example, when X-rays are incident on the FPD 32, electron-hole pairs (e-h pairs) corresponding to the amount of X-ray irradiation are emitted from the photoconductive film 40, and the electron- The hole pairs are accumulated in the capacitor 42 of each pixel 34. The charge accumulated in the capacitor 42 is read out as image data when the TFT 44 is turned on. The image data read from each pixel 34 of the FPD 32 is input to the charge amplifier 38 via the data line, and is amplified and output according to the voltage level.

  When the imaging device 10 (imaging unit 12) vibrates, the charge amount of the capacitor 58 of the charge amplifier 38 of the FPD 32 changes, and the potential of the output signal of the operational amplifier 56 changes accordingly. The vibration detection unit 17 detects whether or not the potential change amount of the output signal of the charge amplifier 38 (output signal of the FPD 32) exceeds a preset allowable vibration range, and vibration exceeding the allowable vibration range has occurred. If this is detected, a vibration detection signal indicating that fact is output.

  Here, when vibration exceeding the allowable vibration range occurs, the amount of charge of the capacitor 58 of the charge amplifier 38, that is, the amount of change in the potential of the output signal of the operational amplifier 56 is the capacitance value of the capacitor 58 or before the vibration occurs. It differs depending on the potential of the output signal of the operational amplifier 56. Further, the reference detected as vibration is changed according to the set allowable vibration range. Therefore, the allowable vibration range should be appropriately determined in consideration of these.

  Next, the operation of the photographing apparatus 10 will be described.

  When shooting conditions or shooting modes are set by the user in the shooting instruction unit 20 and the shooting button is pressed down to the first level, the shooting apparatus 10 is in a shooting ready state under the control of the control unit 22.

  Subsequently, shooting is started when the shooting button is pushed down to the second level. When imaging is started, the imaging unit 12 emits radiation with intensity set according to imaging conditions or imaging modes from the radiation source 26 for a set time. The irradiated radiation passes through the subject H on the imaging table 28 and enters the FPD 32 of the radiation detection unit 30, and the radiation transmitted through the subject H is converted into an electrical signal (radiation image data).

  Subsequently, the captured radiographic image data is read from the FPD 32, and data processing such as A / D conversion is performed by the imaging data processing unit 14. In the image processing unit 16, image processing such as offset correction and afterimage correction is performed on the radiation image data after the data processing. The radiographic image data after the image processing is supplied to the output unit 18 and displayed on a monitor or printed out, for example.

  Here, at the time of photographing the subject H, if the vibration detection unit 17 detects that the vibration exceeding the vibration allowable range has occurred before the radiation irradiation, the control unit 22 does not exceed the vibration allowable range. Until the size is reduced, the imaging unit 12 stops irradiation and controls the subject H not to be captured. That is, the subject H cannot be photographed.

  Accordingly, it is possible to prevent radiographic images that may cause image defects due to the occurrence of vibration exceeding the allowable vibration range. Therefore, it is possible to prevent unnecessary radiation irradiation and printout of radiation images that may have image defects.

  In addition, when it is detected by the vibration detection unit 17 that the vibration exceeding the allowable vibration range has occurred during the irradiation of the radiation before the irradiation of the radiation is completed, the vibration detection unit 17 supplies the vibration detection unit 17 with the vibration. Based on the vibration detection signal, the imaging unit 12 stops radiation irradiation, and the output unit 18 performs control so that the radiation image for which radiation irradiation has been stopped is not printed out from the printer. That is, shooting is stopped before shooting is completed.

  As a result, it is possible to cancel the print output of the radiation image in which an image defect may have occurred due to the occurrence of vibration exceeding the allowable vibration range. That is, since unnecessary print output can be prevented, the cost can be reduced accordingly.

  Further, when it is detected by the vibration detection unit 17 that the vibration exceeding the allowable vibration range is generated during the radiation irradiation after the radiation irradiation is completed, the vibration detection unit 17 supplies the vibration detection unit 17 with the vibration. Based on the vibration detection signal, the photographing unit 12 controls the output unit 18 to display a message instructing to re-photograph the subject H on the monitor. In this case, the imaging has been completed, but the captured radiographic image may have a defect image.

  As a result, the user of the imaging apparatus has determined that it is necessary to redo the imaging of the subject H because an image defect has occurred in the captured radiographic image due to the occurrence of vibration exceeding the allowable vibration range without making a judgment by himself / herself. I can know. Further, by performing re-imaging, a radiographic image free from image defects due to vibration can be obtained. For example, in the case of a medical diagnostic image, misdiagnosis can be prevented.

  In the above embodiment, the vibration detection unit 17 is configured to detect whether or not vibration exceeding the vibration allowable range has occurred during shooting based on the output signal (analog signal) of the charge amplifier of the FPD 32. The present invention is not limited to this, and it may be configured to detect whether or not vibration exceeding a vibration allowable range has occurred during photographing based on an output signal (digital signal) of the photographing data processing unit 14.

The present invention is basically as described above.
The radiographic imaging apparatus of the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications and changes may be made without departing from the gist of the present invention. It is.

It is a block diagram of one embodiment showing composition of a radiographic imaging device of the present invention. It is a circuit diagram showing the structure of FPD shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radiation imaging device 12 Imaging part 14 Imaging data processing part 16 Image processing part 17 Vibration detection part 18 Output part 20 Imaging | photography instruction | indication part 22 Control part 24 Irradiation control part 26 Radiation source 28 Imaging stand 30 Radiation detection part 32 FPD
34 pixels
36 Equivalent circuit of data line 38 Charge amplifier 40 Photoconductive film 42, 54, 58 Capacitor 44 TFT
46, 48 electrode 50 voltage source 52 resistance element 56 operational amplifier

Claims (5)

A radiation image capturing apparatus that irradiates a subject with radiation from a radiation source, detects radiation transmitted through the subject with a flat panel radiation detector, and generates a radiation image in which the subject is captured,
A radiographic imaging apparatus comprising: a vibration detection unit that detects whether or not vibration exceeding a preset vibration allowable range has occurred based on a change in an output signal of the radiation detector. A radiation image capturing apparatus that irradiates a subject with radiation from a radiation source, detects radiation transmitted through the subject with a flat panel radiation detector, and generates a radiation image in which the subject is captured,
An imaging data processing unit that performs data processing including A / D conversion on the output signal of the radiation detector;
A radiographic imaging apparatus comprising: a vibration detection unit that detects whether or not vibration exceeding a preset vibration allowable range has occurred based on a change in an output signal of the imaging data processing unit. A control unit for controlling the operation of the radiographic apparatus,
When the vibration detection unit detects that the vibration exceeding the vibration allowable range has occurred before the radiation irradiation, the control unit is configured to reduce the vibration to a level not exceeding the vibration allowable range. The radiation image capturing apparatus according to claim 1, wherein the radiation image capturing apparatus is controlled so as to stop the irradiation and to not capture the subject. A control unit that controls the operation of the radiographic imaging apparatus; and a printer that prints out the radiographic image,
The control unit stops the radiation irradiation when the vibration detection unit detects that the vibration exceeding the vibration allowable range has occurred during the radiation irradiation before the radiation irradiation is completed. 3. The radiographic image capturing apparatus according to claim 1, wherein the radiographic image is controlled so as not to print out the radiographic image for which irradiation of the radiation has been stopped from the printer. 4. A control unit that controls the operation of the radiographic imaging apparatus, and a monitor that displays the radiographic image,
The control unit instructs the subject to be re-photographed when the vibration detection unit detects that a vibration exceeding the allowable vibration range is generated during the radiation irradiation after the radiation irradiation is completed. The radiographic imaging apparatus according to claim 1, wherein a message to be displayed is controlled to be displayed on the monitor.

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