JPH0779444B2 - X-ray diagnostic device - Google Patents

Description

The present invention relates to the technical field of X-ray imaging apparatuses, and more particularly to an X-ray diagnostic apparatus using digital radiography.

[Prior Art] An X-ray diagnostic apparatus is generally configured as shown in FIG. Reference numeral 1 denotes an X-ray tube that irradiates the subject 3 with X-rays when a high voltage generated by the high-voltage generator 2 is applied. Reference numeral 4 denotes an image intensifier (II) that receives an image of X-rays that has been exposed by the X-ray tube 1 and that has passed through the subject 3 and that converts this image into an optical image, which was output from II4. The optical image is projected into the image pickup tube of the camera head shown by 6 via the optical system and the diaphragm shown by 5, and is converted into a video signal by the camera control unit 7,
This video signal is input to the video processor indicated by 8. In this video processor 8, the video signal from the camera control unit 7 is passed through the input selector 9 and, if necessary, further through the log converter (logAmp) 10 into a digital signal in the A / D converter indicated by 11. Convert. Then, the video signal converted into the digital signal is subjected to appropriate arithmetic processing in the arithmetic unit indicated by 12 and then stored in the frame memory 1 indicated by 13. The frame memory 13 stores the X-ray image of the subject 3 before injection of the contrast agent, which is converted into a video signal. Reference numeral 14 denotes a frame memory 2 having the same structure as the frame memory 13, and this frame memory 14 is used for storing a video signal obtained by converting an X-ray image of the subject 3 after the injection of the contrast agent. Process to frame memory
It is exactly the same as the process leading to the storage of the video signal in 13. 2 stored in these two frame memories 13 and 14
A subtraction video signal is obtained by subjecting the video signals of one subject image to subtraction processing in the arithmetic unit 12. Then, the subtraction video signal is applied to the image enhancement circuit 15
Via the D / A converter shown in 16 and then sent to a monitor 17 outside the video processor 8 for monitor display, and also sent to a video disk recorder shown in 18 for video display. It is designed to be recorded on a disc. In the video processor 8, there is a D / A converter 19 for converting an image signal of the subject image stored in the frame memory 13 or the frame memory 14 which is not subtracted into an analog signal.
The video signal output from 19 can be input to the monitor indicated by 20 to be visualized. In addition, the D / A converter 16
Alternatively, the analog video signal output from 19 can be transmitted to a multi-format camera indicated by 21 and recorded on a film. The output signal of the video disk recorder 18 is sent to the input switch 9 of the video processor 8 at an arbitrary time, and applied to the monitor 17 through the video processor 8 so that it can be visualized.

Reference numeral 22 is an X-ray interface, and reference numeral 23 is a system controller and an operation panel of the video processor 8.

[Problems to be Solved by the Invention] By the way, in the X-ray diagnostic apparatus as described above, there are some problems, that is, in order to perform contrast imaging of the coronary arteries surrounding the heart and other blood vessels, A circulatory system imaging device is used, but this device uses different imaging methods from two different directions in order to accurately grasp the position and state of blood vessels stretched in various directions in the body of the object. A diagnostic technique called a so-called biplane is performed in which images are simultaneously taken by the system. However, in the above-described conventional apparatus, it is necessary to use two apparatuses including an image processing system, or to take a picture twice by changing the direction, so that the overall construction of the picture taking system is complicated. In addition, the cost of the entire system is increased. In addition, there is a drawback that the operation becomes extremely complicated.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an X-ray diagnostic apparatus in which a contrast agent is injected into a subject and a blood vessel image in the subject is taken, and different regions of the subject are examined. A plurality of X-ray tubes that respectively irradiate X-rays, and a unit that drives each of the X-ray tubes by shifting the X-ray irradiation start time based on the difference in the arrival time of the contrast agent at each of the sites. The X-ray tube is arranged so as to face the X-ray tube, and the X-ray of the portion is synchronized with the X-ray exposure of the X-ray tube facing the X-ray tube.
A plurality of imaging means for successively capturing a plurality of X-ray transmission images consecutively, a storage means for storing an X-ray fluoroscopic image before injection of a contrast agent corresponding to each of the imaging means, and an imaging means after the injection of the contrast agent. An X-ray diagnostic apparatus comprising: a calculation unit that subtracts an image stored in the storage unit from a captured X-ray transmission image to obtain a subtraction image; and a display unit that displays the subtraction image. To do.

[Operation] The driving unit drives the X-ray tube by shifting the X-ray irradiation start time based on the difference in the arrival time of the contrast agent at each site. The X-ray tube irradiates different parts of the subject with X-rays, respectively, and the imaging means continuously captures X-ray transmission images in a plurality of frames. The calculation means subtracts the image stored in the storage means from the X-ray transmission image photographed by the imaging means to obtain a subtraction image, and the display means displays this subtraction image.

[Embodiment] A first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

Reference numeral 1 denotes an X-ray tube that irradiates the subject 3 with X-rays when a high voltage generated by the high-voltage generator 2 is applied. Reference numeral 4 denotes an image intensifier (II) that receives an image of X-rays that has been exposed by the X-ray tube 1 and that has passed through the subject 3 and that converts this image into an optical image, which was output from II4. The optical image is projected into the image pickup tube of the camera head shown by 6 through the optical system and the diaphragm shown by 5, and is converted into a video signal by the camera control unit 7 and input to the video processor shown by this video signal 8. It The above is the X-ray system on the F side, and the same applies to the X-ray system on the other L side. That is, the X-ray tube 101 is controlled by the high-voltage generator 102, and the transmission image of the subject generated by this is input to the video processor indicated by 8 via the II 104, the optical system 105, the camera head 106, and the camera control unit 107. To be done. The system controller 23 in the video processor 8 has a built-in synchronizing signal generator (not shown) and outputs a vertical synchronizing signal (hereinafter, referred to as VD signal). For example, for each field in synchronization with the VD signal. A pulse is generated and supplied to the interface 22. still,
This VD signal is also supplied to the camera heads 6 and 106 on the F and L sides, respectively. The interface 22 divides the input pulse and alternately generates trigger signals on the F side and the L side as shown in FIGS. 2 (2) and 2 (3).
Side and L side high voltage generators 2, 102 are supplied. As a result, high pressure is supplied to the X-ray tubes 1 and 101 on both the F and L sides, and X
Alternate lines.

First, when X-rays are emitted from the F-side X-ray tube 1 in synchronization with the first VD signal, an optical image is incident on the F-side camera head 6 through the F-side II 4 and the optical system 5, It is accumulated on this photocathode. Then, in synchronization with this at the time of the second VD signal, the image information accumulated in the camera head 6 from the F side is read out, and the video signal is output. In addition, this second VD
At the time of signal, X-rays are emitted from the L-side X-ray tube 101, and a transmission image by the X-rays is accumulated in the L-side camera head 106. The accumulated image information on the L side is the third VD
It is read at the time of signalling. Thus, F for each field
The video signals obtained alternately on the L side and the L side are alternately input to the input selector 9 via the camera control units 7 and 107 of the next stage, and alternately as shown in FIG. 2 (6) by the control signal of the system controller 23. Either the F side or the L side is selected for transmission to the 10 A / D converters.

The video signal (for example, the F side) converted into a digital signal by the A / D converter 10 is sent to the arithmetic unit 12 via the log converter 11 and subjected to appropriate arithmetic processing and then the frame memory 13
Memorized in. Similarly, the L-side video signal sent to the next field is stored in the frame memory 13a.
Reference numerals 14 and 14a denote frame memories having the same structure as the frame memories 13 and 13a. The frame memories 13 and 13a store the images of the subject 3 before the injection of the contrast agent. The images of the subject 3 after injection of the contrast agent are stored in 14a. The two types of subject image signals stored in these four frame memories 13, 13a, 14, 14a are subtracted by the arithmetic unit 12 by the pair of frame memories 13 and 14, and the frame memories 13a, 14a.
It is input to the image enhancement circuit 15 in the next stage. In this circuit, the subtraction image, for example, by emphasizing the edges of blood vessels,
It is easy to see. After that, the processed images on the F side and L side are D / A converters 16 for the images on the F side and D / A for the images on the L side.
It is converted into an analog signal by the converter 19 and output to each monitor shown by 17 and 20 for display. Further, the outputs of the D / A converters 16 and 19 are also output to video disk recorders (hereinafter referred to as VDRs) 18 and 24, respectively, and are configured to be recorded on the disks.

The outputs of the VDRs 18, 24 are connected to the above-mentioned input selector 9 in the video processor 8, and the camera control unit 7, 107 is controlled by the control signal from the system controller 23.
It can be used for the processing of this processor 8 instead of the video signal from. As a result, the past image recorded in the VDR can be image-processed again and used for display.

Next, a second embodiment will be described with reference to FIG. The configuration is the same as the block diagram shown in FIG. 1, but is different in that the timing of X-ray irradiation and the timing of imaging are controlled according to the difference in the arrival time of the contrast agent. That is, F side and L
The X-ray image detection system on the side is set to different parts of the subject 3 (for example, front and rear parts of blood flow in the same blood vessel), and
As in the timing of the figure, for example, the X-ray tube 1 on the F side is exposed (see FIG. 3 (1)) for a predetermined period before and after the arrival of the contrast agent at the X position of a certain blood vessel, and the video signals of a plurality of frames are continuously made. (See (3) of the same figure), and then X from the X-ray tube on the L side set at the Y position distal to the X position of this blood vessel.
By performing the radiation exposure by shifting the contrast agent arrival time from the start of the X-ray radiation on the R side (see (2) in the same figure), the image signals of the predetermined period before and after the arrival of the contrast agent at the Y position are obtained. (See (4) of the same figure). By doing so, there is an excellent effect that it is possible to diagnose two regions of the subject by one injection of the contrast agent.

Next, a third embodiment will be described with reference to FIGS. 4 and 5. This third embodiment is the same as the first embodiment in that two camera heads to which a synchronizing signal is applied from the outside are used, but a portion corresponding to the video processor 8 in FIG. 1 is shown in FIG. It is configured as follows. In other words, a video signal with an aspect ratio (horizontal to vertical ratio of the image) of 4: 3 is processed by the D / A converter.
The F side and the L side are respectively supplied from 16 and 19 to the 4: 3 aspect ratio monitor. At the same time, the output of the image emphasizing circuit 15 is supplied to the pair of speed converting circuits 25 and 26 and converted as shown in FIG. That is, the 4: 3 monitors 17 and 20 display, for example, by adding character information related to this image to the side of a circular perspective image, but this image data is used for displaying a general perspective image with an aspect ratio of 1: 1. When the images are displayed on the monitors 27 and 28, the circular image area portion is discriminated for each horizontal scanning line, and the read speed at the portion is slightly delayed in the HD signal (horizontal synchronizing signal) and output. The video signal output after being subjected to such processing is converted into an analog signal by the D / A converters 29 and 30, and the 1: 1 monitor 27, 28.
Is supplied to. In addition, this 1: 1 monitor 27,28 for general fluoroscopy
In addition to displaying the image-processed video signal from the video processor 8, it is also possible to directly input and display the video signal from each of the camera heads 7 and 107. For this purpose, a pair of changeover switches 31 and 32 are provided so that they can be selected as needed by a control signal from the system controller 23. Although the above-described embodiments have been described with respect to the X-ray image detection system having two systems, three or more systems may be provided. In this case, it is necessary to control the collection timing according to the number of systems.

[Effects of the Invention] As described in detail above, according to the present invention, a subtraction image with less noise caused by the displacement of the subject before and after the injection of the contrast agent can be imaged at multiple sites of the subject by one injection of the contrast agent. It is possible to reduce unnecessary X-ray exposure.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a time chart showing the operation of the apparatus shown in FIG. 1, FIG. 3 is a time chart showing a second embodiment of the present invention, and FIG. FIG. 5 is a partial block diagram showing a third embodiment of the present invention, FIG. 5 is a diagram showing the operation of the apparatus shown in FIG. 4, and FIG. 6 is a block diagram showing a conventional X-ray diagnostic apparatus. 1,101 …… X-ray tube, 2,102 …… High voltage generator 3 …… Subject, 4,104 …… II 5,105 …… Optical system 6,106 …… Camera head 8 …… Video processor, 9 …… Input selector 10 …… A / D converter 16,19 …… D / A converter 17,20 …… Monitor

Claims (1)

[Claims] 1. An X-ray diagnostic apparatus for injecting a contrast medium into a subject and taking a blood vessel image in the subject, comprising: a plurality of X-ray tubes which respectively irradiate different regions of the subject with X-rays; Means for driving each X-ray tube by shifting the X-ray irradiation start time based on the difference in the arrival time of the contrast agent at each of the sites, and the X-ray of the X-ray tube that is arranged so as to face the X-ray tube. A plurality of imaging means for successively capturing a plurality of X-ray transmission images of the region in synchronization with the exposure, and a storage means for storing the X-ray fluoroscopic images before injection of the contrast agent in correspondence with the respective imaging means. And a calculation means for obtaining a subtraction image by subtracting the image stored in the storage means from the X-ray transmission image taken by the imaging means after the injection of the contrast agent,
An X-ray diagnostic apparatus comprising: a display unit that displays the subtraction image.