JP2016080593A - Radioactive ray inspection method and radioactive ray inspection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactive ray inspection method capable of maintaining the brightness of images while preventing increase of exposure dose to a subject even when a radioactive ray generator and a radioactive ray detection device degradation over age.SOLUTION: A radioactive ray generator 11 generates an X-ray 16 of constant level to irradiate a subject 15 with the X-ray 16. A radioactive ray detection device 12 detects an X-ray image 17 transmitted through the subject 15 and outputs an image signal 18. The radioactive ray detection device 12 controls the gain of the image signal 18 so that the brightness of the image which is formed using the image signal 19 with constant level of the X-ray 16 from the radioactive ray generator 11.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a radiation inspection method and a radiation inspection system that detect a radiation image and output a video signal.

  Conventionally, in an X-ray inspection system using X-rays as radiation, the subject is irradiated with X-rays output from an X-ray generator such as an X-ray tube, and an X-ray image transmitted through the subject is an X-ray image. Detected by an X-ray detector such as a tube or flat panel detector (FPD), outputs a video signal, captures this video signal into the control device, and displays the video on the monitor of the control device for inspection. Yes.

  In such an X-ray inspection system, the X-ray generation device and the X-ray detection device are consumable parts, so that deterioration with time occurs with use.

  The X-ray detection device includes, for example, an information signal such as luminance relating to control of X-ray irradiation conditions from the X-ray generation device, such as automatic brightness control (ABC) or automatic exposure control (AEC). Is fed back to the control device. The control device controls the X-ray output from the X-ray generator so that the luminance of the video is constant based on the information signal such as the luminance. As a result, the image quality necessary for the inspection is ensured so that the luminance of the image becomes constant against the deterioration of the X-ray generator and the X-ray detector with time.

JP-A-7-79384

  X-ray generators and X-ray detectors are consumable parts that deteriorate over time with use. The influence of the deterioration of the X-ray generator and the X-ray detector is compensated by controlling the X-ray irradiation conditions of the X-ray generator so that the luminance of the video is constant in order to reduce the luminance of the video. However, since control of the X-ray irradiation conditions of the X-ray generator mostly increases the output of X-rays, there is a possibility that the X-ray dose incident on the subject increases and the exposure dose to the subject increases.

  A problem to be solved by the present invention is a radiation inspection method capable of keeping the brightness of an image constant while suppressing an increase in exposure dose to a subject with respect to deterioration over time of a radiation generator and a radiation detector. To provide a radiological examination system.

  The radiation inspection method of this embodiment irradiates a subject with radiation from a radiation generator that generates radiation with a constant output. A radiographic image that has passed through the subject is detected by a radiation detection device and an image signal is output. The image signal is such that the luminance of the image constituted by the image signal is constant while the radiation output from the radiation generator is constant. To control the gain.

It is a lineblock diagram of a radiation inspection system showing one embodiment. It is a flowchart which shows the 1st radiation inspection method by a radiation inspection system same as the above. It is a flowchart which shows the 2nd radiation inspection method by a radiation inspection system same as the above.

  Hereinafter, an embodiment will be described with reference to FIGS. 1 to 3.

  As shown in FIG. 1, the radiation inspection system 10 includes a radiation generation device 11, a radiation detection device 12, and a control device 13. The radiation generation device 11 and the radiation detection device 12 are arranged to face each other, and the subject 15 to be inspected is positioned between the radiation generation device 11 and the radiation detection device 12. The X-ray 16 as the radiation output from the radiation generator 11 is irradiated to the subject 15, the X-ray image 17 as the radiation image transmitted through the subject 15 is detected by the radiation detection device 12, and an image is displayed from the radiation detection device 12. The signal 18 is output to the control device 13. The control device 13 outputs a control signal 19 to the radiation generation device 11 and the radiation detection device 12.

  The radiation generator 11 is constituted by an X-ray tube 21 which is an X-ray source that generates X-rays 16. The X-ray tube 21 generates X-rays 16 having a predetermined output (dose) based on a control signal 19 from the control device 13.

  The radiation detection apparatus 12 is configured by an X-ray detector 22 such as an X-ray image tube or a flat panel detector (FPD). In the case of an X-ray image tube, the X-ray image 17 incident on the incident surface of the X-ray image tube is converted into a visible light image and output from the output surface of the X-ray image tube. The image signal 18 is output from the camera. In the case of a flat detector, the X-ray image 17 incident on the flat detector is converted into visible light, the visible light is detected by a photoelectric conversion element, and a video signal 18 is output.

  The X-ray detector 22, that is, the X-ray image tube camera and the flat panel detector, has an image processing function for adjusting the video signal 18 to be output. In the image processing function, processing for increasing or decreasing the gain of the video signal 18 is performed so that the luminance of the video constituted by the video signal 18 is constant. Specifically, the amplification factor by the amplifier when reading a signal from the image sensor or the photoelectric conversion element is adjusted. The X-ray detector 22 detects an X-ray image 17 based on a control signal 19 from the control device 13 and outputs a video signal 18 with a gain adjusted.

  The control device 13 is constituted by a personal computer (PC) or the like, for example. The control device 13 receives the video signal 18 from the X-ray detector 22 and displays the video on a monitor. The control device 13 transmits a control signal 19 to the X-ray tube 21 and the X-ray detector 22 to control the X-ray tube 21 and the X-ray detector 22. The control device 13 has an image processing function for adjusting the video signal 18. In the image processing function, not only the video signal 18 but also a noise signal is amplified as a result of the gain increase. Therefore, noise reduction or integration processing is performed to reduce noise. In the integration process, a plurality of images acquired by the X-ray detector 22 are integrated to reduce noise and improve resolution. The noise reduction process may be performed by the image processing function of the X-ray detector 22.

  The integration process requires time to acquire the required number of images, and this depends on the number of images, the speed response of the processing system, and the time response (frame rate, etc.) of the image capture portion. For this reason, in the control device 13, a countermeasure is taken by setting a high speed specification such as a storage area such as a memory and a CPU of an arithmetic mechanism such as a PC that performs arithmetic processing, and in the X-ray detector 22, For example, the same measures can be taken by setting and developing a high frame rate of the camera.

  Information relating to the luminance of the video can be detected from the video signal 18. The control device 13 includes luminance detection means for detecting information relating to the luminance of the video from the video signal 18.

  Next, a first radiation inspection method by the radiation inspection system 10 will be described with reference to the flowchart of FIG.

  In the first radiological examination method, the control device 13 increases the gain of the video signal 18 so that the luminance of the video constituted by the video signal 18 is constant while the output of the X-ray 16 from the X-ray tube 21 is constant. Control.

  Note that the X-ray tube 21 may have a fixed (constant) output of the X-ray 16 or may control the X-ray 16 to be output even if the output of the X-ray 16 can be changed. Also good.

  The X-ray tube 21 generates X-rays 16 with a constant output, and irradiates the subject 15 with the X-rays 16 (step S1).

  The X-ray image 17 transmitted through the subject 15 is detected by the X-ray detector 22 (step S2), and the video signal 18 is output from the X-ray detector 22 to the control device 13 (step S3).

  The control device 13 receives the video signal 18 from the X-ray detector 22 and detects information related to the luminance of the video from the video signal 18. The control device 13 determines whether or not the detected luminance is within a preset reference value range (step S4), and if the detected luminance is within the reference value range, the video composed of the video signal 18 is displayed. Output to the monitor.

  When the detected luminance is not within the range of the reference value, the control device 13 transmits a control signal 19 for adjusting to a gain necessary for the detected luminance to be within the range of the reference value to the X-ray detector 22.

  The X-ray detector 22 receives the control signal 19 from the control device 13 and adjusts the gain of the video signal 18 (step S5), and outputs the gain-adjusted control signal 19 to the control device 13.

  Thus, for example, even if there is a possibility that the luminance of the video image is lowered due to deterioration with time of the X-ray tube 21 or the X-ray detector 22, by increasing the gain of the video signal 18, the luminance of the video image can be reduced. Can be kept constant. Therefore, it is possible to provide the radiation inspection system 10 that can extend the time during which a desired image can be obtained without increasing the exposure dose of the subject 15.

  Since the signal amplified by the gain increase is not only the video signal 18, but also the noise signal is amplified, it is possible to obtain a video with good image quality by performing noise reduction processing or noise reduction processing by integration processing or the like. .

  As described above, according to the first radiation inspection method, the X-ray tube 21 and the X-ray detector 22 are deteriorated with time without increasing the output of the X-ray 16 from the X-ray 21, that is, to the subject 15. The brightness of the image can be kept constant without increasing the exposure dose.

  When the gain adjustment reaches a preset upper limit value, it is determined that it is time to replace the X-ray tube 21 or the X-ray detector 22, and the control device 13 notifies that fact. Further, when the X-ray output from the X-ray tube 21 is increased with respect to deterioration over time as in the prior art, the deterioration of the X-ray detector 22 is also accelerated accordingly. When the gain is adjusted, the deterioration of the X-ray detector 22 is not accelerated, and the time when the X-ray detector 22 needs to be replaced can be lengthened.

  Next, a second radiation inspection method by the radiation inspection system 10 will be described with reference to the flowchart of FIG.

  In the second radiological examination method, the control device 13 has a range in which the gain of the video signal 18 can be controlled by the X-ray detector 22 so that the luminance of the video constituted by the video signal 18 is constant (set in advance). The X-ray tube 21 controls the gain of the video signal 18 so that the luminance of the video composed of the video signal 18 is constant while the output of the X-ray 16 from the X-ray tube 21 is constant, and the X-ray When the gain control of the video signal 18 by the detector 22 reaches a preset upper limit, the output of the X-ray 16 from the X-ray tube 21 is controlled so that the luminance of the video constituted by the video signal 18 becomes constant. To do.

  The X-ray tube 21 can change the output of the X-ray 16.

  Then, the X-ray tube 21 generates X-rays 16 and irradiates the subject 15 with the X-rays 16 (step S11).

  The X-ray image 17 transmitted through the subject 15 is detected by the X-ray detector 22 (step S12), and the video signal 18 is output from the X-ray detector 22 to the control device 13 (step S13).

  The control device 13 receives the video signal 18 from the X-ray detector 22 and detects information related to the luminance of the video from the video signal 18. The control device 13 determines whether or not the detected luminance is within a preset reference value range (step S14), and if the detected luminance is within the reference value range, the video composed of the video signal 18 is displayed. Output to the monitor.

  The control device 13 can control the gain of the video signal 18 by the X-ray detector 22 so that the luminance of the video constituted by the video signal 18 is constant when the detected luminance is not within the range of the reference value. It is determined whether it is within the range, that is, whether the gain control of the video signal 18 by the X-ray detector 22 has reached the upper limit (step S15).

  Control of the gain of the video signal 18 by the X-ray detector 22 is such that the control of the gain of the video signal 18 by the X-ray detector 22 does not reach the upper limit and the brightness of the video constituted by the video signal 18 is constant. Is determined to be within a possible range, a control signal 19 for adjusting the gain necessary for the detected luminance to fall within the range of the reference value is transmitted to the X-ray detector 22. The X-ray detector 22 receives the control signal 19 from the control device 13 and adjusts the gain of the video signal 18 (step S16), and outputs the gain-adjusted control signal 19 to the control device 13.

  Thus, for example, even if there is a possibility that the luminance of the video image is lowered due to deterioration with time of the X-ray tube 21 or the X-ray detector 22, by increasing the gain of the video signal 18, the luminance of the video image can be reduced. Can be kept constant. Therefore, it is possible to provide the radiation inspection system 10 that can extend the time during which a desired image can be obtained without increasing the exposure dose of the subject 15.

  Since the signal amplified by the gain increase is not only the video signal 18, but also the noise signal is amplified, it is possible to obtain a video with good image quality by performing noise reduction processing or noise reduction processing by integration processing or the like. .

  Further, when the gain control of the video signal 18 by the X-ray detector 22 reaches the upper limit, the X-ray tube is set so that the detected luminance becomes an output of the X-ray 16 necessary for entering the range of the reference value. A control signal 19 for adjusting the output of 21 is transmitted to the X-ray tube 21. The X-ray tube 21 receives the control signal 19 and adjusts the output of the X-ray 16 (step S17).

  It should be noted that when the gain control of the video signal 18 by the X-ray detector 22 reaches the upper limit, it is preferable to notify the control device 13 to that effect. In addition, if it is necessary to increase the output of the X-ray 16 after the gain control of the video signal 18 by the X-ray detector 22 reaches the upper limit, the control device 13 notifies that fact and It is preferable that the output of the X-ray 16 is increased only when approval is obtained.

  When the gain control of the video signal 18 by the X-ray detector 22 reaches the upper limit and the output of the X-ray 16 needs to be increased, the control device 13 notifies that and obtains the operator's approval. Only in this case, it is preferable that the output of the X-ray 16 is increased.

  As described above, according to the second radiation inspection method, the X-ray detector is configured so that the luminance of the image formed by the image signal 18 is constant with respect to the aging of the X-ray tube 21 and the X-ray detector 22. If the gain of the video signal 18 can be controlled by 22, the luminance of the video can be increased without increasing the output of the X-ray 16 from the X-ray tube 21, that is, without increasing the exposure dose to the subject 15. When the gain control of the video signal 18 reaches the upper limit, it is time to replace the X-ray tube 21 and the X-ray detector 22, but the X-ray 16 from the X-ray tube 21 is replaced. Therefore, the inspection can be continued while obtaining an image of good image quality until the X-ray tube 21 and the X-ray detector 22 are replaced.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10 Radiation inspection system
11 Radiation generator
12 Radiation detector
13 Control device
15 Subject
16 X-rays as radiation
17 X-ray image as radiation image
18 Video signal

Claims (4)

Irradiating the subject with the radiation from a radiation generator that generates radiation of a constant output,
A radiation image transmitted through the subject is detected by a radiation detection device and an image signal is output, and a luminance of an image constituted by the image signal is constant while an output of the radiation from the radiation generation device is constant. As described above, the radiation inspection method is characterized by controlling the gain of the video signal. Irradiate the subject with radiation from the radiation generator,
A radiation image transmitted through the subject is detected by a radiation detection device and a video signal is output.
The radiation output from the radiation generator remains constant within a range in which the gain of the video signal can be controlled by the radiation detection device so that the brightness of the image composed of the video signal is constant. When the gain of the video signal is controlled so that the luminance of the video constituted by the signal becomes constant, and the control of the gain of the video signal by the radiation detection device reaches the upper limit, the gain is constituted by the video signal A radiation inspection method, wherein the radiation output from the radiation generator is controlled so that the luminance of an image is constant. A radiation generator for generating a constant output of radiation and irradiating the subject with the radiation;
The radiographic image transmitted through the subject is detected and an image signal is output, and the image is configured such that the luminance of the image constituted by the image signal is constant while the output of the radiation from the radiation generator is constant. A radiation inspection system comprising: a radiation detection device that controls a gain of a signal. A radiation generator for irradiating the subject with radiation;
A radiation detection device that detects a radiation image transmitted through the subject and outputs a video signal, and controls a gain of the video signal so that a luminance of a video constituted by the video signal is constant;
The radiation output from the radiation generator remains constant within a range in which the gain of the video signal can be controlled by the radiation detection device so that the brightness of the image composed of the video signal is constant. When the gain of the video signal is controlled so that the luminance of the video constituted by the signal becomes constant, and the control of the gain of the video signal by the radiation detection device reaches the upper limit, the gain is constituted by the video signal And a control device that controls the output of the radiation from the radiation generator so that the brightness of the image is constant.

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