JPH0145367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention belongs to the technical field of diagnostic medical equipment, and particularly to the technical field of X-ray imaging devices.

[Technical background of the invention and its problems] In conventional X-ray imaging devices, pulsed X-rays are used to display images by exposing patients to pulsed X-rays in order to reduce the patient's exposure dose. line television equipment is used. When taking an X-ray photograph, this pulse X-ray television device generally confirms the target region by displaying a fluoroscopic image of the target region of the subject to be photographed on a display device, such as a television monitor. . Such a pulse
The X-ray television device includes an X-ray tube 6 as shown in FIG.
An image intensifier (hereinafter referred to as
It is called. ) converted into a fluorescent image with the input fluorescent surface of 1,
This fluorescent image is appropriately amplified and outputted to the output fluorescent surface of 1, and this output fluorescent image is imaged by a television camera 3 via an optical system (tandem lens system) 2, and obtained by imaging. The configuration is such that a video signal is stored in a memory in a signal processing unit 9 via a camera controller 4, and a video signal and a television scanning signal are output from the signal processing unit 9 to display an X-ray fluoroscopic image on a television monitor 5. have.

In the pulse X-ray television apparatus having the above configuration,
The radiation of pulsed X-rays by the ray tube 6 is carried out by the signal processing section 9.
A control signal for controlling intermittent irradiation is output to the X-ray controller 8, and a high voltage is intermittently applied from the high voltage generator 7 according to the rate signal output from the X-ray controller 8.
This is done by applying a voltage to the wire tube 6.

However, in the pulse X-ray television apparatus, it is necessary to change the pulse X-ray irradiation interval depending on the region to be imaged. This is because the movement of the target region to be photographed is different. To explain in more detail, if pulsed X-rays with a relatively large time interval are irradiated to a region with relatively large movements, the image will be in a frame-by-frame state, so it is necessary to reduce the time interval of the pulsed X-rays. It's coming. On the other hand, irradiating pulsed X-rays with short time intervals to areas with little or no movement will unnecessarily increase the patient's radiation dose; It becomes necessary to increase the spacing. For these reasons, the number of X-ray irradiations per unit time is varied. However, in this case, the video output of the television camera 3 changes depending on the number of X-ray irradiations per unit time. In conventional pulse X-ray television equipment, in order to maintain the output of the television camera 3 at a constant level, the operator must reset the X-ray conditions such as the X-ray tube voltage and X-ray tube current according to the surgical procedure. First, the resetting operation was extremely complicated.

[Purpose of the Invention] This invention has been made in view of the above-mentioned circumstances, and provides a method for controlling a television camera by keeping the basic amount of light incident on the television camera constant per unit time regardless of the length of the exposure interval of pulsed X-rays. It is an object of the present invention to provide an X-ray photographing apparatus that can always keep the video output substantially constant.

[Summary of the invention] The outline of this invention for achieving the above object is as follows:
X per unit time corresponding to the target part of the subject
In an X-ray imaging device that obtains an X-ray transmission image by varying the number of radiation exposures, converts it into an optical image, and then photographs the optical image with a television camera via an optical system,
It is equipped with an aperture that is placed in the optical system and that changes the amount of light of the optical image, and an aperture controller that controls the aperture, and it is equipped with This device is characterized by adjusting the aperture with an aperture controller so that the amount of incident light is constant. Here, the basic amount of light incident on the television camera is the amount of light that would be incident on the television camera when no subject is placed.

[Embodiment of the Invention] FIG. 2 is a schematic block diagram showing an embodiment of the invention.

The pulse X-ray television apparatus shown in FIG. 2 differs from the pulse X-ray television apparatus shown in FIG. 1 in the following features. That is, the diaphragm 10 is arranged within the parallel rays formed between the primary lens 2A and the secondary lens 2B of the tandem lens system 2 and adjusts the amount of light of the parallel rays, and the signal processing section 9
An aperture controller 11 is newly added to control the aperture amount of the aperture 10 in accordance with the pulsed X-ray exposure interval based on a control signal for controlling intermittent exposure outputted from the aperture 10. . It should be noted that in FIG. 2, the same reference numerals as in FIG. 1 have the same functions as shown in FIG. 1, so a description thereof will be omitted.

Since the pulse X-ray television apparatus shown in FIG. 2 is configured as described above, for example, the television camera 3
When trying to maintain the basic incident light intensity at the basic incident light intensity when the exposure interval of pulsed X-rays is once per second, no matter what the pulsed X-ray exposure interval is, is 10 times per second (the exposure interval is
0.1 seconds), a control signal for controlling intermittent ejection 10 times per second is sent from the signal processing unit 9 to the aperture controller 11.
As a result, the aperture controller 11 controls the aperture 10 to an aperture amount such that the amount of light of the output fluorescent image becomes 1/10. For example, the aperture amount is controlled so that the aperture area of the aperture 10 becomes 1/10.
Therefore, regardless of the length of the pulsed X-ray exposure interval, the basic amount of light incident on the television camera 3 can be automatically and always kept constant. Accordingly, the video output of the television camera 3 can be kept almost constant. Note that the above relationship may not hold depending on the characteristics of the image pickup tube, so in such cases, for each number of exposures per unit time, the light intensity of the output fluorescent image (basic light intensity), or The video output (basic output) of the television camera 3 may be measured in advance, and the aperture amount of the aperture 2 may be determined based on the measurement.

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the embodiment described above, and can be implemented with various modifications within the scope of the gist of the invention.

Note that if an image pickup tube with a bias light is used for the television camera 3 in the pulse X-ray television apparatus having the above configuration, the rise of the video output can be made faster, and the video signal can be outputted efficiently.

[Effects of the Invention] According to the present invention, regardless of the length of the exposure interval of pulsed By keeping the basic amount of incident light constant, it is possible to keep the video output of the television camera almost constant.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing a conventional pulse X-ray television apparatus, and FIG. 2 is a schematic block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Image intensifier, 2... Optical system, 3... Television camera, 10... Aperture, 11... Aperture control device.

Claims (1)

[Claims] 1 Obtain an X-ray transmission image by changing the number of X-ray irradiations per unit time depending on the target area of the subject, convert it into an optical image, and then transmit the optical image with a television camera via an optical system. In an X-ray imaging device that takes an image, an aperture that is arranged in an optical system and that changes the amount of light of an optical image, and an aperture that adjusts the aperture so that the basic amount of light incident on the television camera per unit time is constant. An X-ray imaging device comprising: a controller.