JPH02172444A - X-ray diagnosing device - Google Patents

Abstract

PURPOSE:To enable accurate grasping of the enlargement ratio of an X-ray picture by a method wherein a position relation between a body to be inspected on a sleeping bed top plate and an X-ray tube and an X-ray photographing means is detected, and based on a detecting value, an enlargement ratio SID/a is corrected and determined. CONSTITUTION:A device is provided with a detecting sensor 10 to detect a height H from a floor surface to a sleeping bed top plate 4, a distance detecting sensor 11 to detect a distance (h) from a floor surface to an isocenter A, an angle detecting sensor 12 to detect a slide angle alpha, and an SID detecting sensor 13 to detect the X-ray focus of an X-ray tube 6 and a distance SID to the detecting surfaces of I and 17. By reading detecting signals from the detecting sensors 10-13, the focus distance of the X-ray tube 6 previously contained in the memory 17, distance data (a) to an isocenter A of a C-arm 2, and distance data C1 from a sleeping bed top plate 4 surface to a center C of the photographing portion of a body 5 to be inspected, the enlargement ratio of an X-ray picture is determined of a computing formula of SID= [a-(h-H-C1)/cos alpha]. By displaying the obtained enlargement ratio of the X-ray picture on a monitor 9, an accurate value of, for example, the size of a blood tube can be detected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides information on the circulatory system, for example, from an image signal captured by an X-ray tube and an X-ray imaging means provided opposite to an arm. The present invention relates to an X-ray diagnostic apparatus that obtains an X-ray image, and particularly to an X-ray diagnostic apparatus that has a function of geometrically enlarging an X-ray image displayed on a monitor and a function of displaying the enlargement ratio.

(Prior art) An X-ray diagnostic device that takes X-ray images of the circulatory system 0, for example, blood vessels, can be moved up and down nine times and slid by a holding device 1, as shown in Fig. 3. An X-ray tube 6 and an image intensifier (hereinafter referred to as 1.1 ) 7 are provided facing each other, and the imaging signal obtained from this 1.17 is input to the image processing circuit 8 to obtain an X-ray image.
There is one in which a line image is displayed on a monitor 9.

In this case, the image processing circuit 8 is equipped with a function of geometrically enlarging and displaying the X-ray image on the display surface of the monitor 9.

In such an X-ray diagnostic device, the X-ray image displayed on the display screen of the monitor 9 is enlarged by the image processing circuit 8 to an appropriate size necessary for diagnosis, but in this case, the X-ray image is Information on whether the X-ray image has been magnified is important in accurately diagnosing the imaged area of the patient, so the magnification rate of the X-ray image is usually also displayed on the display surface of the monitor 9. .

By the way, in order to obtain the magnification ratio of the X-ray image, the distance from the X-ray focal point of the X-ray tube 6 to the X-ray detection surface of 1.17 (SID
) and from the X-ray focus of the X-ray tube 6 when the center of the subject is assumed to be the isocenter of the C-shaped arm (the point through which the X-ray beam always passes even if the C-shaped arm rotates or slides) A. The ratio SID to the distance a to this point A
/a was determined and displayed on the display surface of the monitor 9 as the enlargement ratio of the X-ray image. In this case, SID
Since is usually variable, the magnification rate will change depending on the change.

(Problem to be Solved by the Invention) However, when the magnification of an X-ray image is determined by such means, in reality, the center C of the imaged part of the subject is not necessarily located at the isocenter A position, and the As shown in the figure, when the distance from the floor to the isocenter A changes due to the vertical movement of the C-arm 2, or the height H from the floor to the bed top 4, the center C of the subject's imaged part and the isocenter A change. Because of the deviation, an error occurs in the geometrical magnification and an accurate magnification cannot be obtained. For this reason, when it is desired to quantitatively understand, for example, the actual thickness of a blood vessel displayed on a monitor, it becomes impossible to obtain that value accurately.

SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray diagnostic apparatus that can more accurately grasp the magnification ratio of an X-ray image enlarged and displayed on a display means.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has an arm movably held by a holding device, and a subject on a bed top plate supported by a support frame. An X-ray tube and an X-ray imaging means are placed facing each other so as to sandwich the person between them, and the X-ray imaging signal of the imaged area obtained from the X-ray imaging means is processed and the X-ray image is displayed geometrically on the display means. It has a function to enlarge and display, and
The distance from the X-ray focus of the ray tube to the detection surface of the X-ray imaging means (
In an X-ray diagnostic apparatus, the X-ray diagnostic apparatus is configured to display on a display means a magnification of the X-ray image determined by a ratio SID/a between the X-ray focal point of the X-ray tube and the distance a from the isocenter of the arm. a detection means for detecting a relative positional relationship between the subject on the bed top, the X-ray tube, and the X-ray imaging means as the arm moves; and a position detection signal detected by the detection means. The SID/a is originally configured to include an isocenter with respect to a reference position and an arithmetic processing means for determining a magnification rate corrected in accordance with the displacement of the center of the imaging region.

(Function) In the X-ray diagnostic apparatus having such a configuration, the relative positional relationship between the X-ray tube and the X-ray imaging means changes as the subject on the bed top moves and the arm. The positional relationship between the subject on the bed top, the X-ray tube, and the X-ray imaging means at that time is detected, and based on the detection signal, SID/a detects the displacement of the isocenter and the center of the imaged area with respect to the reference position. Since the magnification factor corrected in accordance with is determined, it is possible to accurately know the magnification factor of the X-ray image enlarged and displayed on the display means.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an X-ray system and an imaging system of an X-ray diagnostic apparatus according to the present invention. The same parts as in FIGS. omitted. In this embodiment, as shown in FIG. Distance detection sensor 11. An angle detection sensor 12 that detects the slide angle α is placed on the holding portion of the C-shaped arm 2, and an X-ray focal point of the X-ray tube 6 is placed on the arm support portion of 1.17. , SI to detect the distance SID to the detection surface of I7
Each D detection sensor 13 is provided, and each movement position thereof can be detected.

FIG. 2 shows an example of a block configuration of an arithmetic processing circuit that calculates the magnification ratio of an X-ray image to be enlarged and displayed on a monitor based on detection signals from each of these detection sensors 10 to 13.

As shown in FIG. 2, the detection signals from each of the detection sensors 10 to 13 described above are amplified by an amplifier 14 to a size suitable for signal processing and input to an analog/digital (A/D) converter 15. The digitally converted output signal is taken into the arithmetic processing section 16. This arithmetic processing unit 16 executes an arithmetic operation that takes SID/a into consideration in accordance with the displacement of the isocenter C and the center C of the imaged part with respect to the reference position. ~13 detection signals, the focal length of the X-ray tube 6 stored in the memory 17 in advance, the distance data a to the isocenter A of the C-shaped arm 2, and the center C of the imaged part of the patient 5 from the 4th surface of the bed top plate. The magnification ratio of the X-ray image is determined by reading out the distance data C1 and using the following arithmetic expression.

Magnification rate - mS ID/ [a - (h-H-C1)/c
os a] The data representing the enlargement rate determined by the arithmetic processing section 16 is stored in the buffer 1'3 and then displayed on the monitor 9.

If the X-ray diagnostic apparatus has such a configuration, the relative relationship between the patient 5 on the bed top 4 and the X-ray tubes 6, 1.17 as the C-arm 2 moves up and down and slides. Even if the positional relationship changes, as can be seen from the above equation, the sliding angle a of the C-shaped arm 2, the distance from the floor to the isocenter A, and the height from the floor to the bed top 4 are variable parameters. Based on H and the distance C1 from the bed top 4 to the center C of the imaged part of the subject 5, the denominator term of the above formula is (h-H-C1)/
By cos α, the distance from the isocenter A to the center C of the imaged part of the subject 5 is subtracted from the distance a from the focus of the X-ray tube 6 to the isocenter A, and the distance from the focus of the X-ray tube 6 to the center C of the imaged part is calculated. Since the magnification ratio is calculated by dividing the SID by that value, it is compared with the conventional case where the magnification ratio is calculated from the ratio of the SID to the distance a from the focal point of the X-ray tube 6 to the isocenter A. to obtain a more accurate magnification.

Therefore, by displaying the enlargement ratio of the X-ray image obtained in this way on the monitor 9, the examiner can obtain more accurate values when quantitatively understanding, for example, how thick a blood vessel actually is. can be known.

In the above embodiment, the rotation angle β of the C-arm 2 is assumed to be 0 degrees, and the X-ray tube 6 degrees I, 17 due to the vertical movement and sliding movement of the subject 5 on the bed top 4 and the C-shaped arm 2. The case has been described in which the magnification ratio is calculated by taking into account the correction according to the displacement of the isocenter A and the center C of the imaging region relative to the displacement of the relative positional relationship between the C-arm 2 and the rotation angle β of the C-arm 2. is other than 0 degrees, the opening data and bed top plate 4
An accurate magnification ratio can be obtained by performing calculations in consideration of the horizontal movement position data.

[Effects of the Invention] As described above, according to the present invention, the relative positional relationship between the X-ray tube and the X-ray imaging means changes as the subject on the bed top moves and the arm. At that time, the positional relationship between the patient on the bed top, the X-ray tube, and the X-ray imaging means is detected, and based on the detection signal, SID/a detects the displacement of the isocenter and the center of the imaged area with respect to the reference position. Since the magnification factor corrected accordingly is obtained, it is possible to provide an X-ray diagnostic apparatus that can more accurately grasp the magnification factor of the X-ray image enlarged and displayed on the display means.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the mechanical parts of the X-ray system and the imaging system in an embodiment of the X-ray diagnostic apparatus according to the present invention, and FIG. 2 is a block diagram of the arithmetic processing circuit for determining the magnification rate by arithmetic processing in the same embodiment. 3 and 4 are configuration diagrams showing the mechanical parts of an X-ray system and an imaging system of a conventional X-ray diagnostic apparatus. 1... Holding device, 2... C-shaped arm,
3...Support frame, 4...Bed top plate, 6
...X-ray tube, 7...1, ■, 8...
...Image processing surface, 9...Pa...monitor, 10-1
3...Position detection sensor, 14...Amplifier, 15...A/D converter, 16...
Arithmetic processing unit, 17... Memory, 18...
·buffer.

Claims (1)

[Claims] An X-ray tube and an X-ray imaging means are provided facing each other on an arm movably held by a holding device so as to sandwich the subject on a bed top supported by a support frame, and from this X-ray imaging means. The X-ray imaging means has a function of processing the obtained X-ray imaging signal of the imaging region and geometrically enlarging and displaying the X-ray image on the display means, and detecting the X-ray imaging means from the X-ray focal point of the X-ray tube. The ratio of the distance to the surface (SID) and the distance a from the X-ray focal point of the X-ray tube to the isocenter of the arm SID/
In the X-ray diagnostic apparatus, the magnification ratio of the X-ray image obtained by a is displayed on a display means, in which the X-ray tube and the
a detection means for detecting a relative positional relationship with the linear imaging means, and based on the position detection signal detected by the detection means, the SID/a is corrected according to the displacement of the isocenter with respect to the reference position and the center of the imaged part. An X-ray diagnostic apparatus comprising: arithmetic processing means for determining a magnification ratio.