JPH0591994A - X-ray image pickup system - Google Patents

Abstract

PURPOSE:To bring automatically the image pickup condition at tomographic image pickup to the optimum condition by performing fluoroscopy by moving an X-ray irradiation means and calculating a code of an anatomical program by integrating an electric signal obtd. by detecting brightness of a visible ray image from an image converting device during the whole period of movement. CONSTITUTION:Fluoroscopy is performed by moving an X-ray tube 11 and an image intensifier 12 and an output image of the image intensifier 12 is guided to a photomultiplier 14 and is converted to photocurrent, which is transmitted to a photocurrent integrator 41 for integration. This integrating action is continued until the similar action as the one during tomographic image pickup is finished and the integration action is finished by shuttering X-rays. The integrated value is converted to a digital signal by means of an A/D convertor 42 and is transmitted to an APR code operator 43 and the operated code of an anatomical program is transmitted to a microcomputor 32, where the image pickup condition is read out from an APR memory 35 based on the APR code and is set in an image pickup condition setting device 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray imaging apparatus, and more particularly to improvement of an X-ray imaging apparatus having a tomographic imaging function.

[0002]

2. Description of the Related Art In a conventional X-ray imaging apparatus having a tomographic imaging function, imaging conditions for tomographic imaging are determined as follows. The object is irradiated with X-rays from one direction, the X-rays that have passed through the object are incident on the image intensifier, and the image intensifier converts the X-ray transmission image into a visible light image. Detect the brightness of the image,
The imaging conditions at the time of tomography are calculated based on the fluoroscopic conditions that maintain the brightness at a constant value.

[0003]

However, as in the prior art, the photographing conditions at the time of tomography are obtained based on the brightness of the visible light image converted by the image intensifier in the perspective state from one direction of the subject. Then, the brightness of the visible light image in a perspective state from one direction with respect to the subject and the average value of the brightness of the visible light image in the perspective state from all directions when performing tomography may differ greatly depending on the subject. Therefore, there is a problem that the optimum imaging condition at the time of tomography cannot be obtained.

In view of the above, an object of the present invention is to provide an X-ray imaging apparatus improved so that the imaging conditions at the time of tomography can be automatically optimized.

[0005]

In order to achieve the above object, in the X-ray radiographing apparatus according to the present invention, the X-ray irradiating means and the like are moved for fluoroscopy in the same manner as during tomography.
During the whole period of the movement, the electric signal obtained by detecting the brightness of the visible light image from the image conversion means is integrated, the code of the anatomical program is calculated from this integrated value, and the stored anatomical program is calculated based on the code. Read the program,
As a result, the imaging conditions are set, and then the tomography is performed by the film imaging means. Even when the fluoroscopy is performed, X-rays are emitted from various directions in the same manner as in the tomography, and visible light in all the directions is emitted. The image capturing conditions at the time of tomographic image capturing by film filming are obtained from the integrated value of the image brightness.
Therefore, X-rays are emitted from exactly the same direction during fluoroscopy and during tomography, and the optimum radiography conditions during tomography can be obtained from the brightness during fluoroscopy.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, an X-ray tube 11 and an image intensifier 12 are provided in a fluoroscopic imaging stand 10 with a tomographic function, and these move relative to a subject 20 (for example, move linearly). X-rays can be transmitted to the subject 20 from various directions. X-rays transmitted through the subject 20 are incident on the image intensifier 12, and the X-ray transmission image is converted into a visible light image by the image intensifier 12. This visible light image is
It is converted into an electric video signal by a TV camera coupled to the output surface of the image intensifier 12. If this video signal is sent to a monitor device (not shown) for display, so-called fluoroscopic observation can be performed. At the time of tomography, the X-ray film 15 is inserted in front of the image intensifier 12, and the image intensifier 1
Moves with 2. At the time of tomographic imaging, X-ray transmission images of the subject 20 from each direction are multiply exposed on the film 15 to obtain a tomographic image.

A high voltage is supplied to the X-ray tube 11 from a high voltage generator 36 based on the conditions set by the imaging condition setting device 33 and the fluoroscopic condition setting device 34, whereby X-rays are emitted from the X-ray tube 11. Is irradiated.

Prior to the tomography with the film 15,
In the same manner, the X-ray tube 11 and the image intensifier 12 are moved to perform fluoroscopy. In this case, film 15
Are not inserted in front of the image intensifier 12. That is, when the X-ray exposure switch 31 is pressed and an X-ray exposure signal is sent to the microcomputer 32, the microcomputer 32 causes the fluoroscopic condition (120 KV, 1 mA, 2 s).
ec) is set in the fluoroscopic condition setting device 34, and a high voltage is supplied to the X-ray tube 11 from the high-voltage generator 36 based on the condition, and X-ray exposure is started. This X-ray exposure signal is also sent to the fluoroscopic imaging stand 10 with a tomographic function, and the X-ray tube 11 and the image intensifier 12 start moving.

At this time, the image intensifier 1
The output image of No. 2 is guided to the photomultiplier 14, converted into photocurrent, sent to the photocurrent integrator 41, and integrated. This integration operation is performed until the operation similar to that at the time of tomography is completed, X-rays are cut off, and the integration operation is completed. The integrated value is converted into a digital signal by the A / D converter 42, and then the code of the anatomical program (AP
It is sent to the APR code calculator 43 which calculates the R code. The APR code (5 bits) calculated by this is sent to the microcomputer 32, and the APR code
The photographing conditions are read from the APR memory 35 based on the code.

Here, the APR memory 35 has an anatomical program (imaging condition for each part) obtained by performing a moving operation at the time of tomography using a human body phantom or the like during installation and adjustment of the apparatus. ) Has been written in advance. This anatomical program is displayed by the display 51 arranged on the panel as shown in FIG. An anatomical program button 52 is arranged near the display 51. When the automatic photographing condition setting as in this embodiment is not performed, a desired anatomical program can be set by pressing the corresponding number on the anatomical program button 52.

The shooting conditions thus read out from the APR memory 35 are set in the shooting condition setting unit 33. Then, the X-ray film 15 is the image intensifier 1
2 is inserted in front of and ready for tomography. At this time, if the X-ray exposure switch 31 is pressed, a high voltage is generated from the high voltage generator 36 based on the above set imaging conditions.
And the irradiation of X-rays is started. At the same time, the X-ray tube 11 and the image intensifier 12 in the state where the film 15 is inserted in the fluoroscopic imaging stand with a tomographic function 10 are provided.
The movement of (and the film 15) is started. In this way, multiple exposure is performed on the film 15 and tomography is performed.

If a operative button is provided for each photographic part so that the photographic part can be set with the button and the optimum photographic condition is stored as an anatomical program for each photographic part, a wide variety of varieties can be obtained. A tomographic image of a part can be easily taken under optimum imaging conditions. Further, when the same movement as in tomography is performed without inserting the film 15, the visible light image from the image intensifier 12 is used as a video signal by the TV camera 13 and is displayed by a monitor device (not shown). By doing so, it is possible to judge whether or not the tomographic depth is acceptable, and it is possible to avoid a situation in which re-imaging with the film 15 must be performed.

[0013]

As described in the above embodiments, according to the X-ray photographing apparatus of the present invention, the image converting means and the X-ray irradiating means are moved in the same manner as in the tomographic photographing without using the film, and the image thereof is obtained. Since the imaging conditions at the time of tomographic imaging with a film are calculated from the output image of the conversion means, the optimal imaging conditions can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a view showing a display example of an anatomical program and anatomical program buttons in the same embodiment.

[Explanation of symbols]

 10 Fluorograph base with tomographic function 11 X-ray tube 12 Image intensifier 13 TV camera 14 Photomultiplier 15 Film 20 Subject 31 X-ray exposure switch 32 Microcomputer 33 Imaging condition setting device 34 Fluoroscopic condition setting device 35 APR memory 36 High-voltage generator 41 Photocurrent integrator 42 A / D converter 43 APR code calculator 51 Indicator 52 Anatomical program button

Claims (1)

[Claims] 1. X-ray irradiation means for irradiating X-rays, image conversion means for converting an image by X-rays into an image of visible light, film photographing means for exposing an image by X-rays to a film, and the above-mentioned X
A means for moving the line irradiation means, the image conversion means and the film photographing means for tomography, and a photoelectric conversion means for detecting the luminance of the image of visible light during movement under fluoroscopic conditions and converting it into an electric signal, Means for integrating the electric signal in the moving period, means for calculating a code of an anatomical program from the integrated value, reading an anatomical program stored based on the code to set shooting conditions, and film shooting means. An X-ray imaging apparatus comprising: means for controlling tomography.