JPH10337285A - X-ray diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the deviation of an X-ray irradiation field from the screen of an X-ray plane detector, which is caused by distortion or twist caused in a C-arm by positioning. SOLUTION: The amounts of deviation of an X-ray irradiation field from the screen of an X-ray detecting part, caused by distortion or twist caused by each positioning of a C-arm 1, are detected in advance and stored in a distortion compensation data table 5 as distortion compensation data. During the actual photographing, an angle detecting part 4 detects the angle (position) of the C-arm 1, and according to its angle detection output a control part 6 reads the distortion compensation data corresponding to the current positioning of the C-arm 1 from the table 5 and accordingly controls the movement of an X-ray plane detector 3 via a driver 7. Therefore, the deviation of the irradiation field from the screen can be corrected according to distortion caused in the C-arm 1, and the rate at which a subject is exposed to unnecessary X-rays can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diagnostic apparatus having an X-ray generating section and an X-ray detecting section provided at both ends of an arc-shaped arm such as a C arm or an Ω arm. By correcting "shift" generated between the X-ray irradiation field and the image receiving surface of the X-ray detection unit due to "bending (bending)" and "twisting" (twisting) generated in the arm according to each positioning, The present invention relates to an X-ray diagnostic apparatus for reducing unnecessary exposure to a subject.

[0002]

2. Description of the Related Art Conventionally, X used mainly for circulatory organs
In a circulatory organ holding device as a X-ray diagnostic device, an X-ray generating unit and an X-ray detecting unit are arranged opposite to each other at both ends of a C-shaped arm and fixedly held. Since the X-ray generation unit and the X-ray detection unit are heavy and large, the C-arm is bent or twisted on the order of several tens of mm depending on the positioning. The amount of this shift differs depending on the positioning of the C-arm. However, if this bending or torsion occurs, the X-ray beam is shifted from the center of the image receiving surface of the X-ray detector. We are designing the rigidity of the arm.

[0003]

Considering a case where a region of interest is arranged at an isocenter and the rotation of the C-arm is controlled during diagnosis and treatment using such a circulatory organ holding device, the region of interest is originally C It should be displayed so as to be located at the center of the image displayed on the monitor regardless of the rotational position of the arm.

[0004] However, the conventional circulatory organ holding device has a disadvantage that the region of interest is shifted from the center of the image displayed on the monitor with the rotation of the C-arm.

[0005] This is due to the fact that the amount of deflection of each C arm differs depending on the positioning of the C arm.

That is, the X-ray beam is not always located on the isocenter, and is shifted by the positioning of the C-arm. Then, the relative relationship between the X-ray irradiation field and the image receiving surface of the X-ray detection unit also shifts due to the positioning of the C-arm, and the subject does not contribute to the image (necessary at a location unrelated to diagnostic treatment). Exposure to X-rays.

The rigid design of the C-arm is performed to minimize such useless X-ray exposure and, at a minimum, to keep it within the allowable value defined by the standard. This stiffness design is more difficult than the strength design, and there is a problem that the C-arm becomes large and heavy.
A high-power motor and a transmission system must be provided in order to balance the sliding rotation of the larger and heavier C-arm, and as a result, the entire apparatus is larger and heavier.

The present invention has been made in view of the above problems, and corrects the relative relationship between an X-ray irradiation field and an image receiving surface of an X-ray detection unit even if the C-arm is twisted or bent due to positioning. It is another object of the present invention to provide an X-ray diagnostic apparatus capable of reducing unnecessary exposure of a subject and reducing the size and weight of the C-arm and the apparatus.

[0009]

An X-ray diagnostic apparatus according to the present invention has an arc-shaped arm such as a C-arm or an Ω-arm, in which an X-ray generating unit and an X-ray detecting unit are arranged to face each other.

Then, in order to solve the above-mentioned problem, X
The detection position of the X-rays in the X-ray detection unit is controlled so that the irradiation field of the X-ray flux emitted from the X-ray generation unit matches the image receiving surface of the X-ray detection unit with respect to the irradiation field of the X-ray flux. It has a detection position control means.

More specifically, the detection position control means controls the movement of the position of the X-ray detection unit based on the amount of displacement of the image receiving surface with respect to the irradiation field in accordance with each positioning, so that the X-ray detection unit controls the X-ray detection. The read position of the solid-state detector is read out so as to control a line detection position or read an X-ray image corresponding to the irradiation field based on the amount of displacement of the image receiving surface with respect to the irradiation field according to each positioning. The control controls the X-ray detection position in the X-ray detection unit.

With such a configuration, the relative positional relationship between the X-ray irradiation field and the image receiving surface of the X-ray detector can be kept optimal regardless of the positioning of the C-arm, and the subject can be wasted. X-ray exposure can be reduced.

Further, since the relative positional relationship between the irradiation field and the image receiving surface can be kept optimal irrespective of the positioning of the C-arm, it is possible to provide a low-rigidity C-arm. Can be made smaller and lighter. Since the C-arm can be reduced in size and weight, the high-power motor and transmission system required to balance the slide rotation of the C-arm can be reduced in size and weight. The size and weight of the device can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the X-ray diagnostic apparatus according to the present invention will be described below in detail with reference to the drawings.

First, as shown in FIG. 1, an X-ray diagnostic apparatus according to a first embodiment of the present invention comprises an X-ray generator 2 provided at both ends of a C-arm 1 so as to face each other and a solid-state detector. Vessel 3
(X-ray flat panel detector), an angle detector 4 for detecting an angle of the C arm 1 due to the current positioning, and a C arm 1
And a deflection compensation data table 5 in which deflection compensation data in which a relative positional relationship between the X-ray generator 2 and the X-ray flat panel detector 3 caused by each of the above-mentioned positionings is detected in advance.

The X-ray diagnostic apparatus has an angle detector 4
The controller 6 reads out the deflection compensation data corresponding to the angle detection output from the deflection compensation data table 5, and forms and outputs the detector position control data and the aperture control data corresponding to the deflection compensation data. And a driver 7 for controlling the movement of the position of the X-ray flat panel detector 3 and the position of the X-ray diaphragm of the X-ray generation unit 2 based on the.

Here, the deflection of the C-arm 1 cannot be corrected only by three-dimensional axial movement. That is,
When the C-arm 1 is swung in the RAO direction / LAO direction, twisting occurs, and this must be considered. The amount of twist is determined by placing the C-arm 1 sideways (RAO / LA
O: 90 ° positioning). In order to strictly correct them, six degrees of freedom, that is, movement in three directions and rotation around three axes, should be originally required.

However, the tilt angle of the image receiving surface of the X-ray flat panel detector 3 caused by the torsion of the C-arm 1 is not large enough to directly affect the captured image (perspective image, captured image). Further, the moving amount in the X-ray beam direction (S
ID change).

From the above, in the X-ray diagnostic apparatus, the position of the X-ray flat panel detector 3 and the X-ray diaphragm of the X-ray generation unit 2 are moved in two directions. The relative position between the irradiation field and the image receiving surface is corrected, and deflection compensation data indicating the amount of movement in the two directions for correcting the deviation of the X-ray beam from the isocenter at all C arm positions is calculated or Obtained in advance by actual measurement,
This is stored in the deflection compensation table 5.

The X-ray flat panel detector 3 converts a X-ray image into a visible optical image in a sheet-like X-ray-visible light conversion member (for example, a fluorescent film) and generates an electric charge corresponding to the visible light. 2
A plurality of charge generation elements arranged in a three-dimensional manner, charge storage elements respectively connected to the charge generation elements so as to accumulate the charges, and a reading means for reading out the charge information stored in the charge storage elements. I have. The reading means is a switching element (for example, a thin film transistor: TFT) connected to the charge storage means so that the charge information stored in the charge storage means can be read.
Switching element control means for controlling the switching elements to be turned on and off in row units; signal lines for electrically connecting the outputs of the switching elements in the same column; and selection means for selecting and outputting the output of each signal line (for example, Multiplexer)
And

The charge generating element of the X-ray flat panel detector 3 may be one that directly converts X-rays into charges. In this case, the X-ray-visible light conversion member can be eliminated.

Next, the operation of the X-ray diagnostic apparatus of this embodiment having the above-described configuration will be described.

First, when the C-arm 1 is set to a desired position during imaging of the subject, as shown by a solid line in FIG. 2A, an ideal state where the C-arm 1 is not bent at all. On the other hand, as shown by the two-dot chain line in FIG. 2A, the C arm 1 is bent (and twisted) in accordance with its positioning. When the C-arm 1 is not bent, an X-ray flux center of X-rays emitted from the X-ray generation unit 2 as shown as a center line P in FIG. The center of the image receiving surface of the X-ray flat panel detector 3 coincides with the center of the image receiving surface. However, when the C-arm 1 is bent, the X-ray flux center and the center as shown by the center line Q in FIG. The relative positional relationship with the center of the image receiving surface of the X-ray flat panel detector 3 shown as the line R is shifted, the X-ray beam deviates from the isocenter, and the region of interest deviates from the center of the X-ray flux.

Here, when correcting the center lines Q and R due to the bending of the C-arm 1, the X-ray flat panel detector 3 does not control the movement, and the X-ray aperture blades (pre- It is also possible to make the X-ray irradiation field coincide with the image receiving surface of the X-ray flat panel detector 3 by controlling only the movement of the collimator), but in such a movement control, the X-ray beam remains off the isocenter. There is a concern that the region of interest may be out of the observation field of view.

For this reason, in the X-ray diagnostic apparatus according to this embodiment, when the positioning control of the C-arm 1 is performed, the angle detector 4 shown in FIG. An angle of the main shaft rotation angle is detected, and this angle detection output is supplied to the control unit 6. The control unit 6 reads out the deflection compensation data corresponding to the current positioning of the C-arm 1 from the deflection compensation table 5 based on the angle detection output. Then, based on the read deflection compensation data, the X-ray generation unit 2 is moved so that the center of the image receiving surface of the X-ray flat panel detector 3 is located on the extension of the line connecting the center of the X-ray flux and the isocenter. It generates generator position control data for control and detector position control data for movement control of the X-ray flat panel detector 3 and supplies them to the driver 7.

The driver 7 controls the movement of the X-ray generator 2 and the X-ray plane detector 3 based on the generator position control data and the detector position control data.

More specifically, the moving mechanism of the X-ray flat panel detector 3 is constituted by an XY table capable of moving in two directions substantially perpendicular to the X-ray irradiation direction. The X-direction moving mechanism that enables the X-Y table to move in the X direction transmits the power of the motor 17 to the lead screw 15 by a belt, a pulley, or the like as shown in FIG. 3 (the motor may be directly connected). The X-ray flat panel detector 3 is fixed to a lead screw block 16 that moves in accordance with the rotation of the lead screw 15, and the X-ray flat panel detector 3 is controlled to move in the X direction.

The Y-direction moving mechanism has the same configuration except that the direction for controlling the movement of the X-ray flat panel detector 3 is perpendicular to the X direction.

The X-ray of the X-ray generator 2 shown in FIG.
The moving mechanism of the X-ray aperture blade 10 originally has
An irradiation field control mechanism for electrically moving the X-ray aperture blade 10 corresponding to the SID is provided. For this reason, in the X-ray diagnostic apparatus of this embodiment, this irradiation field control mechanism is used as it is.

By driving such an irradiation field control mechanism of the X-ray generator 2 and a moving mechanism of the X-ray flat panel detector 3 based on the generator position control data and the detector position control data, the C arm 2B, the center of the image receiving surface of the X-ray flat panel detector 3 is always positioned on the extension of the line connecting the center of the X-ray flux and the isocenter, as shown in FIG. Thus, the movement of the X-ray diaphragm 10 and the X-ray flat panel detector 3 can be controlled.

Therefore, it is possible to prevent inconvenience that the region of interest deviates from the observation field of view, and it is possible to reduce unnecessary exposure of the subject to X-rays.

Further, since the relative positional relationship between the irradiation field and the image receiving surface can be kept optimal irrespective of the positioning of the C-arm 1, it is possible to provide a low-rigidity C-arm. The size and weight of the arm can be reduced. Since the size and weight of the C-arm can be reduced, the high-power motor and transmission system required to balance the slide rotation of the C-arm can be reduced in size and weight. It is possible to reduce the size and weight of the X-ray diagnostic apparatus.

In the description of the first embodiment,
The controller 6 calculates the generator position control data and the detector position control data based on the deflection compensation data corresponding to the current angle detection output of the C arm 1. If necessary, such as when the deflection amount is large, the angle detection output from the angle detection unit 4, the movement amount of the X-ray flat panel detector 3, the movement amount of the X-ray diaphragm blade, and the SID are comprehensively calculated. You may.

The cross-sectional shape (rigidity design) of the C-arm 1
In some cases, the shift amount of the X-ray beam in the CRA / CAU direction becomes small and may be ignored. In such a case, only the moving mechanism in the RAO / LAO direction may be provided instead of the moving mechanism in the two directions.

Next, a second embodiment of the X-ray diagnostic apparatus according to the present invention will be described.

The X-ray diagnostic apparatus of the first embodiment controls the movement of the X-ray flat panel detector 3 and the X-ray diaphragm 10 of the X-ray generator 2 according to the deflection of the C-arm 1 or the like. However, the X-ray diagnostic apparatus according to the second embodiment controls the read address of the X-ray flat panel detector 3 in accordance with the deflection of the C-arm 1 and the like to control the X-ray corresponding to the X-ray irradiation field. Only the line image is read from the image receiving surface of the X-ray flat panel detector 3.

The X-ray diagnostic apparatus according to the second embodiment is different from the X-ray diagnostic apparatus according to the first embodiment only in this point. The description given above is omitted.

That is, in the X-ray diagnostic apparatus according to the second embodiment, the X-ray flat panel detector 3 is provided between the irradiation field and the image receiving surface due to bending or twisting caused by each positioning of the C-arm 1. Even if there is a shift, an X-ray generator having a size capable of receiving an X-ray image by X-ray irradiation of the X-ray generator 2 is provided. That is, the size of the X-ray flat panel detector 3 is a size in which bending and twisting caused by each positioning of the C-arm 1 are considered in advance.

When the angle detection output from the angle detection unit 4 is supplied, the control unit 6 reads the corresponding deflection compensation data from the deflection compensation data table 5, and based on the deflection compensation data, the X-ray generation unit. In addition to forming the generation unit position control data for controlling the movement of the second X-ray diaphragm 10, the read address of the X-ray flat panel detector 3 is formed.
The X-ray aperture blades 10 are set on the basis of the position control data of the generator so that the X-ray flux center coincides with the isocenter.
, And read control of the X-ray flat panel detector 3 based on the read address.

More specifically, as shown in FIG.
The image receiving area of the X-ray image received by the X-ray flat panel detector 3 when no bending or twisting occurs in the area A shown by a dashed line in FIG. This causes bending and twisting of the C-arm 1 so that the X-ray aperture blade 1 is adjusted so that the X-ray flux center coincides with the isocenter.
As a result of the movement control of 0, if it is moved to the area B indicated by the solid line in FIG. 4, the control unit 6 forms a read address of the area B and supplies it to the X-ray flat panel detector 3.

Accordingly, the relative positional relationship between the irradiation field and the image receiving surface can be kept optimal irrespective of the bending or twisting of the C-arm 1, and unnecessary exposure of the subject can be reduced. For example, the same effects as those of the X-ray diagnostic apparatus according to the above-described first embodiment can be obtained.

In addition, since the control of the relative positional relationship on the X-ray flat panel detector 3 side is performed by controlling the read address, the moving mechanism on the X-ray flat panel detector 3 side is omitted. (Mechanical moving mechanism X
Since only the moving mechanism of the line diaphragm 10 can be used, hardware can be reduced and the configuration can be simplified.

Finally, the description of each of the above embodiments is an example of the present invention. For this reason, the present invention is not limited to each embodiment, and it is needless to say that various modifications can be made according to the design and the like within a range not departing from the technical idea according to the present invention. is there.

[0044]

According to the X-ray diagnostic apparatus of the present invention, the relative positional relationship between the X-ray irradiation field and the image receiving surface of the X-ray detector can be kept optimal regardless of the positioning of the C-arm. Therefore, it is possible to reduce unnecessary X-ray exposure of the subject.

In addition, since the relative positional relationship between the irradiation field and the image receiving surface can be kept optimal regardless of the positioning of the C-arm, it is possible to provide a low-rigidity C-arm. Can be made smaller and lighter. Since the C-arm can be reduced in size and weight, the high-power motor and transmission system required to balance the slide rotation of the C-arm can be reduced in size and weight. The size and weight of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of an X-ray diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a view for explaining movement control of a solid state detector with respect to bending of a C-arm or the like in the X-ray diagnostic apparatus of the embodiment.

FIG. 3 is a diagram for explaining a movement control mechanism of the solid state detector.

FIG. 4 is a diagram illustrating a state in which a read address of a solid-state detector is controlled in accordance with bending of a C-arm or the like in the X-ray diagnostic apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

1 ... C arm, 2 ... X-ray generator, 3 ... X-ray flat panel detector,
4 ... Angle detection unit 5 ... Deflection compensation data table, 6 ... Control unit, 7 ... Driver, 10 ... X-ray diaphragm blade

Claims (5)

[Claims] An X-ray diagnostic apparatus in which an X-ray generation unit and an X-ray detection unit are disposed opposite to each other on an arcuate arm, comprising: an irradiation field of an X-ray flux emitted from the X-ray generation unit; An X-ray diagnostic apparatus comprising: a detection position control unit that controls a detection position of an X-ray in the X-ray detection unit so that an image receiving surface of the X-ray detection unit with respect to a field matches. 2. The method according to claim 1, wherein the detecting position control unit controls a position of the X-ray detection unit based on a shift amount of the image receiving surface with respect to the irradiation field according to each positioning so that the irradiation field and the image receiving surface match. The X-ray diagnostic apparatus according to claim 1, wherein the position of the X-ray detected by the X-ray detection unit is controlled by controlling the movement of the X-ray. 3. The detection position control means, based on a shift amount of an image receiving surface with respect to the irradiation field according to each positioning, of a line connecting an X-ray focal point of an X-ray flux from the X-ray generation unit and an isocenter. The position of the X-ray detection unit and the position of the X-ray diaphragm of the X-ray generation unit are moved and controlled such that the center of the image receiving surface of the X-ray detection unit is positioned on the extension, so that the X-ray detection is performed. The X-ray diagnostic apparatus according to claim 1, wherein a detection position of the X-ray in the section is controlled. 4. The X-ray diagnostic apparatus according to claim 1, wherein the X-ray detector is a solid-state detector formed by a plurality of solid-state imaging devices. . 5. The X-ray detection unit according to claim 1, wherein said X-ray detecting unit is configured to control said X-ray detection unit even if a shift occurs between said irradiation field and an image receiving surface due to each positioning.
An X-ray flat panel detector in which a plurality of detection elements are arranged so as to be able to receive an X-ray image by the X-ray irradiation of the X-ray generation unit, wherein the detection position control means controls the irradiation field according to each positioning. The readout position of the X-ray flat panel detector is controlled so as to read out the X-ray image corresponding to the irradiation field based on the shift amount of the image receiving surface.
2. The X-ray diagnostic apparatus according to claim 1, wherein a detection position of the line is controlled.