JP3520650B2 - X-ray imaging equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an X-ray imaging apparatus that captures and displays an X-ray transmission image using an X-ray TV system, and in particular, creates a road map image. The present invention relates to an X-ray imaging device having a function of displaying images. 2. Description of the Related Art A road map image is an image used as a guide for operations such as catheter insertion. For example, when trying to insert a catheter into a target blood vessel, an X-ray TV system displays an X-ray fluoroscopic image, and simply observing the image shows the catheter in the image, but does not show the blood vessel. It is not known whether the catheter has been inserted into the target vessel. [0003] Therefore, a blood vessel image is obtained in advance by an angiography method, the black-and-white image is inverted, and then superimposed on an X-ray fluoroscopic image displayed in real time as a reference image. This image is called a road map image. In this road map image, a white band-shaped blood vessel image is superimposed on a normal X-ray fluoroscopic image showing bones and the like, and a catheter is also shown. Thus, it is possible to confirm that the catheter is correctly inserted into the blood vessel. A blood vessel image serving as a reference image is obtained by digital subtraction of an X-ray transmission image before injection of a contrast agent from an X-ray transmission image after injection of a contrast agent, or while the contrast agent flows. Hold D for digital subtraction between the higher peak image and the lower peak image at
It can be obtained by SA or the like. [0005] However, conventionally, there is a limitation that imaging must be performed under exactly the same conditions when capturing a reference image and when capturing and displaying an X-ray fluoroscopic image. Was a problem. That is, for example, if the field size of the image intensifier is different between the time of capturing the reference image and the time of capturing the X-ray fluoroscopic image, the magnification rate of the image is different. Overlapping is meaningless. Similarly, the position of the subject changes,
The height of the examination table should not change. Therefore, since the position of the subject, the height of the examination table, the size of the visual field of the image intensifier, and the like must be the same and the reference image and the X-ray fluoroscopic image must be taken, the restriction is large and the degree of freedom is impaired. In some cases, special imaging needs to be performed only to obtain a reference image used for a road map image, which causes a problem of an increase in exposure dose to a patient. In view of the above, the present invention provides an appropriate road map even when the position of the subject, the height of the examination table, the size of the visual field of the image intensifier, and the like differ between when the reference image is captured and when the perspective image is captured. An object of the present invention is to provide an X-ray imaging apparatus improved so that an image can be created and displayed. In order to achieve the above object, in an X-ray imaging apparatus according to the present invention, an X-ray generating means, an X-ray transmitted through a subject, and an X-ray transmission image are formed. An X-ray image that can be converted into an optical image and whose field of view size can be switched
Optical image conversion means, imaging means for obtaining an image signal of the optical image, image display means for receiving the image signal and displaying the image, means for detecting the position of the subject, and X-ray image-optical image conversion means Means for detecting the position of the reference image, recording means for recording the reference image together with information on the visual field size at the time of imaging, the position of the subject, and the position of the X-ray image-optical image conversion means, and the reference image read from the recording means. To
Based on the read field size and position information and the information on the field size at the time of fluoroscopy, the position of the subject, and the position of the X-ray image-optical image converter, the position is shifted and the position is shifted for X-ray fluoroscopy. Image processing means for superimposing on an image is provided. If the field size of the X-ray image-optical image conversion means, the position of the subject, and the position of the X-ray image-optical image conversion means are known,
The size of the captured image is known. Therefore, these imaging parameters are recorded together with the reference image, read out when the reference image is read out later, and compared with imaging parameters such as the visual field size and position information at the time of X-ray fluoroscopy. It is possible to calculate at what magnification the image should be enlarged or reduced to have the same size as the perspective image. Also, by using imaging parameters such as a visual field size and position information at the time of capturing a reference image and imaging parameters such as a visual field size and positional information at the time of X-ray fluoroscopy, it is possible to calculate how much the positional deviation between the two images is. . Therefore, the image processing means
By performing these calculations, the reference image is enlarged or reduced based on the calculation, the position is shifted, and the reference image is superimposed on the perspective image. Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, a subject 10 is placed on a table 18 of a medical examination table 11, and X-rays are transmitted from an X-ray tube 12 through a collimator 13.
The lines are illuminated. X-rays transmitted through the subject 10 are image intensifiers (II) 14.
And the X-ray transmission image is converted into a visible light image. This optical image is guided to the television camera 17 via the optical system 15 and the aperture device 16, and an image signal is obtained. This X-ray image signal is sent to the image monitor 22 via the image processor 21 and an X-ray fluoroscopic image is displayed. Image processing device 21
Converts an input image signal into digital image data and performs various image processing such as image enlargement / reduction, image shift (movement of position), and addition / subtraction between images. The recording device 23 records an X-ray image before or after image processing. The examination table 11 has a table 18 on which the subject 10 is placed, and this table 18 can be moved up and down, left and right, and back and forth. Although not shown in the drawing, the examination table 11 has a frame that integrally holds the image intensifier 14, the optical system 15, the aperture device 16, and the television camera 17, and the image intensifier 14, the like, and the like. The height of the can be adjusted. The table 18, the image intensifier 14, and the like are driven by the examination table driving device 32, and the position and height thereof are determined. The X-ray control device 31 includes an examination table driving device 32
To control the position and height of the table 18 of the examination table 11 and the height of the image intensifier 14 and the like. The information on the position and height is returned from the examination table driving device 32 to the X-ray control device 31. The opening amount of the leaf of the collimator 13 is controlled by the collimator driving device 33 under the control of the X-ray control device 31. A high voltage or the like is supplied to the X-ray tube 12 from an X-ray power supply device 34. The X-ray control device 31 controls the X-ray power supply device 34, the aperture device 16 and the like in addition to the above. Further X
The line control device 31 controls the image intensifier 14 to switch its visual field size. X-ray controller 3
1 and the image processing apparatus 21 always communicate with each other and share necessary information. Next, a case where a road map image of the abdomen is created and displayed will be described. First, a blood vessel image of the abdomen as a reference image is created by DSA. That is,
Here, the field size of the image intensifier 14 is set to the maximum of 12
(The field size of the image intensifier 14 is switched between four sizes of 12, 9, 7.5, and 6 inches.) In this state, a contrast medium is injected into a blood vessel, and an X-ray transmission image before injection is digitally subtracted from an X-ray transmission image at the time of injection. This signal processing is performed by the image processing device 21.
It is performed by Thus, a blood vessel image 41 of the entire abdomen is obtained as shown in FIG. Along with this image data, the field size of the image intensifier 14 at this time, the height and position of the table 18 (both in the vertical and horizontal directions), the height of the image intensifier 14 and the like, and the SID (X-ray focus / image in) Information on the distance between the image receiving surfaces of the tensifier 14) is also recorded in the recording device 23. Thereafter, X-ray fluoroscopy is performed when the catheter is inserted. At this time, the field size of the image intensifier 14 is switched to, for example, 9 inches. As a result, the image receiving surface of the image intensifier 14 has a diameter of 9 mm.
Since an inch image is output after being enlarged to fill the entire output screen and is taken by the television camera 17, an enlarged X-ray fluoroscopic image as shown in FIG. Is displayed. By moving the table 18, the desired catheter image 42 and the background bone image 43
And the like are displayed. The blood vessel image is not shown in the X-ray fluoroscopic image.
Therefore, it is not possible to confirm whether the catheter is certainly inserted into a desired blood vessel only by observing the fluoroscopic image. Therefore, a road map image is created by superimposing the reference image on the X-ray fluoroscopic image, and is displayed. That is, the blood vessel image of the entire abdomen previously created and recorded in the recording device 23 is read from the recording device 23. At this time, parameters such as the visual field size of the image intensifier 14 at the time of capturing the reference image are also read. The size of the field of view of the current (during fluoroscopy) image intensifier 14, the height of the table 18,
Position, height of image intensifier 14, etc., SI
By capturing parameters such as D from the examination table driving device 32 and the X-ray control device 31, the image processing device 21 compares both parameters and calculates a magnification for making the reference image the same size as the fluoroscopic image. . Then, using this magnification, the blood vessel image 41 as the reference image is enlarged or reduced. At the time of enlargement, interpolation calculation is also performed. Further, the image processing device 21 calculates a shift amount for adjusting the position of the reference image to the position of the perspective image from the amount of movement of the table 18 and the geometric magnification rate, and based on the calculated amount,
The enlarged or reduced blood vessel image 41 is shifted, black-and-white inverted, and superimposed on the X-ray fluoroscopic image. As a result, a road map image is completed, and the image monitor 22 displays a reference image (blood vessel image) which is enlarged and aligned and becomes a white band due to black and white reversal, as shown in FIG. 44 is superimposed and displayed on the fluoroscopic image including the catheter image 42 and the bone image 43. So if you look at this image,
It is clear which part of the blood vessel the catheter is inserted into. The enlargement ratio is determined by the height of the table 18, the height of the image receiving surface of the image intensifier 14, and the SID.
However, the height may be obtained by using a value obtained by correcting the height of the table 18 in consideration of the actual thickness of the subject 10 (the height of the target portion). Further, if the field size of the image intensifier 14 is changed, the distortion of the image appears differently. Therefore, those distortions are measured in advance, and when the reference image is enlarged or reduced, the distortion is corrected. The corrected enlarged / reduced reference image may be superimposed on the perspective image. As described above, according to the X-ray imaging apparatus of the present invention, imaging can be performed freely without being conscious of what visual field size, position, and height are used for X-ray fluoroscopy. Since a reference image having the same size and position as the X-ray fluoroscopic image can be created from the obtained image, an appropriate road map image can be obtained more easily. In addition, since it is not necessary to take an image just to obtain a reference image used in the road map image, the exposure dose to the patient can be reduced.

[Brief description of the drawings] FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a schematic diagram showing an image. [Explanation of symbols] 10 subject 11 Examination table 12 X-ray tube 13 Collimator 14 Image Intensifier 15 Optical system 16 Aperture device 17 TV Camera 18 Table 21 Image processing device 22 Image monitor device 23 Recording device 31 X-ray controller 32 Examination table drive 33 Collimator drive 34 X-ray power supply

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 6/00-6/14

Claims (1)

(57) [Claim 1] X-ray generating means and an X-ray image-optical system capable of switching a visual field size, wherein an X-ray transmitted through a subject is incident to convert an X-ray transmission image into an optical image. Image conversion means, imaging means for obtaining an image signal of the optical image, image display means for receiving the image signal and displaying the image, means for detecting the position of the subject, and X-ray image-optical image conversion means. Means for detecting the position, the reference image, the size of the field of view at the time of imaging,
Recording means for recording together with information on the position of the subject and the position of the X-ray image-optical image conversion means, and the reference image read out from the recording means, the field size read out therewith, the positional information and the field size in fluoroscopy Image processing means for enlarging or reducing the position of the subject based on the information on the position of the subject and the X-ray image-optical image conversion means, shifting the position, and superimposing on the X-ray fluoroscopic image.
Line imaging device.