JP2002263094A - Fluororoentgenograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a sectional image of a photographing field larger than an X-ray detector even to be photographed by a fluororoentgenograph in which a supporting arm cannot be rotated over 360 deg.. SOLUTION: The fluororoentgenograph comprises a rotating means 15 for rotating an arm C 5 around a rotary axis A1, a movement controller 33 for moving the X-ray detector 7 to two positions, a data acquisition unit 37 for acquiring data while moving the rotating means 15, and a controller 39 for reconstituting a CT image based on the acquired data. Since the data of the CT can be reconstituted if there is an angle of (180 deg.+α), a CT image of a larger tomographic field than the detector can be tomographed even by the supporting arm which can rotate less than 360 deg. like the arm C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluoroscopic apparatus for rotating an X-ray source and a two-dimensional X-ray detector around an object to take an X-ray fluoroscopic image.

[0002]

2. Description of the Related Art For example, for diagnosis and treatment of liver cancer,
There is a need for vascular information of both the portal vein and the arteries. Generally, an X-ray CT apparatus in which an X-ray tube and an X-ray detector are rotated around a subject by 360 ° to capture a three-dimensional image of a site of interest is preferable for imaging of a portal vein. The X-ray angiography apparatus which rotates a C-arm provided with an X-ray tube and an X-ray detector facing each other and stops at a desired position to capture a two-dimensional fluoroscopic image of a site of interest is preferable. It is.

[0003] If they are arranged in one operating room, their occupied area becomes too large. Therefore, an X-ray CT apparatus and an X-ray angiography apparatus are installed in one room, and both apparatuses are used by one examination table. There is a device (for example, referred to as an angiographic CT device or an IVR-CT device) configured to perform an inspection. However, such a device not only requires a large space for installation, but also is very expensive, so that hospital facilities which can be introduced are extremely limited.

Therefore, by using a cone beam CT technique in an apparatus such as an X-ray angiography apparatus or a therapeutic X-ray simulator, it is possible to obtain not only a two-dimensional fluoroscopic image but also a three-dimensional tomographic image. Conceivable.

However, in the above-described apparatus, the size of the X-ray detector is generally not sufficient as compared with the X-ray CT apparatus, and the imaging field of view is generally small. The fact is that you cannot shoot. Therefore, by rotating the X-ray tube and the X-ray detector over a 360 ° angle with the center of the X-ray tube being shifted from the rotation axis of the support arm, it is possible to obtain a field of view for two X-ray detectors (Japanese Patent Laid-Open Publication No. No. 11-9583) may be used.

[0006]

However, the prior art having such a structure has the following problems. That is, a support arm such as a C-arm provided in an X-ray angiography apparatus or a therapeutic X-ray simulator is not configured to be able to rotate the X-ray tube and the X-ray detector around the subject over 360 °. However, it is not possible to take a tomographic image by using the above technique.

[0007] The present invention has been made in view of such circumstances, and even in a device in which the support arm cannot rotate over 360 °, a tomographic image having an imaging field of view larger than that of an X-ray detector can be obtained. It is an object of the present invention to provide an X-ray fluoroscopic apparatus that can also perform radiography.

[0008]

The present invention has the following configuration to achieve the above object. That is, according to the first aspect of the present invention, the X-ray source and the two-dimensional X-ray detector are rotated around the subject to obtain an X-ray fluoroscopic image.
In a fluoroscopy apparatus, a rotating means for rotating a support arm having an X-ray source and a two-dimensional X-ray detector facing each other around a rotation axis at less than 360 °, and a moving means for moving the two-dimensional X-ray detector Data acquisition means for moving the two-dimensional X-ray detector by the movement means and collecting data while driving the rotation means at each position, and data processing for reconstructing a CT image based on the collected data Means,
It is characterized by having.

The invention described in claim 2 is the first invention.
3. The X-ray fluoroscopic apparatus according to item 1, further comprising: a collimator moving unit that moves the collimator so that only the two-dimensional X-ray detector is irradiated with X-rays according to the operation of the moving unit. It is.

[0010] Further, the invention according to claim 3 is based on claim 1.
Alternatively, in the X-ray fluoroscopic apparatus described in 2, the moving means moves the two-dimensional X-ray detector symmetrically in two directions from a center position.

The invention described in claim 4 is the first invention.
4. In the X-ray fluoroscopic apparatus according to any one of Items 3 to 3, the data processing means performs a CT image reconstruction process after synthesizing data collected by the two-dimensional X-ray detector at different positions. It is a feature.

[Operation] The operation of the first aspect of the invention is as follows. That is, the position of the two-dimensional X-ray detector is shifted from the rotation axis of the rotating means by the moving means, and data is collected by the data collecting means while being rotated by the rotating means in that state. Next, the two-dimensional X-ray detector is shifted to a different state by the moving means, and data is collected while being rotated again by the rotating means. The CT image data is 180
Since it can be reconstructed if ° + α, a CT image can be reconstructed from data collected by rotation of less than 360 °.

According to the second aspect of the present invention, since the two-dimensional X-ray detector moves, the X-ray irradiation range is adjusted by operating the collimator moving means accordingly.

According to the third aspect of the present invention, the two-dimensional X-ray detector is symmetrically moved in two directions from the center position by the moving means.

According to the fourth aspect of the present invention, after the data collected in a state where the two-dimensional X-ray detector is located at a different position, the CT image reconstruction processing is generally performed. I do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. 1 to 5 relate to an embodiment of the present invention. FIG. 1 is a side view showing a schematic configuration of an X-ray angiography apparatus as an X-ray fluoroscopic apparatus, and FIG. 2 shows the schematic configuration. It is a block diagram. 3 and 4 are schematic configuration diagrams of a moving mechanism, and FIG. 5 is a diagram illustrating a movable range of the two-dimensional X-ray detector.

The X-ray angiography apparatus according to this embodiment originally takes an X-ray fluoroscopic image of a subject M placed on a bed 1 in a state where a contrast agent is applied to the subject M. This is an apparatus for performing angiography.

In this embodiment, the bed 1 is configured to be able to move up and down and to move back and forth in the horizontal direction, and the C arm 5 is configured to be movable in the horizontal direction along the ceiling rail 3 attached to the ceiling surface. Have been. This C arm 5
For example, an X-ray detector 7 composed of an FPD (Flat Panel Detector) and an X-ray source 9 arranged to face the X-ray detector 7 on the imaging axis S are provided. As the X-ray detector 7, a detector other than the FPD may be employed.

The C-arm 5 corresponds to the support arm of the present invention, and the X-ray detector 7 corresponds to the two-dimensional X-ray detector of the present invention.

The C-arm 5 is configured to be rotatable about a vertical axis by an attachment portion 11 to the ceiling rail 3 and is configured to be rotatable about a horizontal axis at a lower end of the suspension arm 13. Further, the outer peripheral portion is gripped by the rotation drive unit 15, and the operation of the rotation drive unit 15 causes the C-arm 5 to rotate about the rotation axis A <b> 1 in the body axis direction.
Are configured to rotate.

In the rotation by the rotation drive section 15, due to its structure, the C-arm 5 is rotated 360 degrees around the rotation axis A1.
It cannot be rotated over °.

The X-ray detector 7 is provided movably on the inner peripheral side of the C-arm 5. As a specific structure, for example, the structures shown in FIGS.

That is, a curved linear guide 17 is mounted on the inner peripheral surface of the C-arm 5, and the X-ray detector 7 is mounted via the linear guide 17 and the base 19. A rack 21 is provided outside one linear guide 17, and is movable along the arc of the C arm 5 by a pinion 27 driven via a motor 23 and a speed reducer 25.

The C-arm 5 by the rotation drive unit 15 described above
Is controlled by the rotation control unit 31, and the movement of the X-ray detector 7 is performed by the movement control unit 33. Also, X-ray bombardment from the X-ray source 9,
The switching of the X-ray irradiation range performed according to the movement control by the movement control unit 33 is performed by the X-ray irradiation control unit 35. The signal detected by the X-ray detector 7 is output to the data collection unit 3
7 collect.

These are centrally controlled by the control unit 39, and reconstruct a CT image based on the data collected by the data collection unit 37 based on an instruction from the operator via the control console 41. Processing such as display on the monitor 43 is performed.

The movement of the X-ray detector 7 by the above-mentioned movement control unit 33 is possible over the range shown in FIGS. 5 (a) and 5 (b). That is, the imaging axis S connecting the X-ray detector 7 and the center of the X-ray source 9 is positioned at the center C, that is, the first position located on the left side from the rotation axis A1, and the center C, ie, located at the right side from the rotation axis A1 And symmetrically movable in two directions over the second position.

Further, in accordance with the movement of the X-ray detector 7, the X-ray irradiation control unit adjusts the X-ray irradiation range of the X-ray source 9 so as to fall on the detection surface of the X-ray detector 7. Examples of the method include changing the irradiation range using an X-ray collimator and tilting the X-ray source 9 itself. Furthermore, the imaging axis S can be held at a third position that coincides with the rotation axis A1, and when held at this third position, fluoroscopy with a normal X-ray angiography apparatus is possible. Has become.

The above-described rotation drive unit 15 and rotation control unit 31 correspond to the rotation unit in the present invention, and the linear guide 17, the motor 23, and the movement control unit 33 correspond to the movement unit.

The X-ray irradiation control unit 35 corresponds to the collimator moving means in the present invention, the data collecting unit 37 corresponds to the data collecting means in the present invention, and the control unit 39
Corresponds to the data processing means.

Next, the operation of the X-ray angiography apparatus configured as described above will be described with reference to FIG.

First, after placing the subject M on the bed 1,
The rotation control unit 31 is driven to move the X-ray detector 7 to the first position.

The C-arm 5 is driven via the rotation control unit 31 to move to the initial position such that the opening of the letter C faces downward (FIG. 6A). In this state, X-ray bombardment is started, and the C-arm 5 is rotated clockwise for about 1 hour.
Rotate by 80 ° (FIG. 6 (b)).

Next, the X-ray detector 7 is moved to the second position via the movement control unit 33, and the X-ray detector 7 is accordingly moved to the second position.
The X-ray irradiation range of the X-ray source 9 is adjusted via the X-ray irradiation controller 35 (FIG. 6C).

With the X-ray detector 7 moved to the second position (FIG. 6 (d)), it is rotated about 180 ° in the opposite direction (counterclockwise) (FIG. 6 (e)). )).

After the above processing, the control section 39 performs a data synthesizing process based on the data collected by the data collecting section 37, reconstructs a CT image, and displays the CT image on the monitor 43.

Here, the data synthesizing process will be described with reference to the schematic diagram of FIG. The data collected by the X-ray CT apparatus is usually two-dimensional data, but is exemplified by one-dimensional data for easy understanding of the description.

In FIG. 7, the vertical axis α indicates the output data (profile data) of the X-ray detector 7, and the horizontal axis indicates the X-ray detector 7
Shows the number of individual X-ray detecting elements constituting the above.
The data collected by the X-ray detector 7 (the first to n-th X-ray detection elements) at the first position is indicated by a solid line in the drawing, and the X-ray detector 7 (the first to n-th X-ray detection elements) The data collected at the second position is indicated by a dotted line in the figure. Further, as described above, when data collection is performed while the X-ray detector 7 is moved to the first position and the second position, k pieces of X-ray detectors collect data in duplicate. And

Here, the data acquired by the X-ray detector 7 at each of the first position and the second position is combined data D
_m can be obtained by the following equation. In _{D m = d m (m =} 1, n) D m = d 'k + mn + β (m = n + 1,2n-k) β = d n -d' k Here, beta is a first position the It indicates a bias value between data obtained by the X-ray detector 7, respectively, in the second position, the calculation of such bias value β is, k pieces of redundant data, corresponding thereto and d _n words from n-k + 1 d it may be performed by either between ^'from 1 ^d' of k. further,
This is performed for data from the depth direction (body axis direction) of the X-ray detector 7 and all angles.

In the above synthesizing process, a step between the two data caused by the time difference between the data acquisition at the first position and the second position is eliminated by performing the bias correction.
Further, a smoothing process may be performed near a joint between the two data. As a result, the two data can be connected smoothly, so that it is possible to prevent an artifact from occurring near a joint in the reconstructed image. The smoothing process may be performed for each data after the bias correction, and after performing the bias correction for all the data in the depth direction of the X-ray detector 7, a two-dimensional smoothing process is performed for the vicinity of the joint. May be.

As described above, the imaging axis S is shifted from the rotation axis A1 to at least two positions by the movement control unit 33, and the data is collected by the data collection unit 37 while rotating the X-ray detector 7 in each state. And the X-ray detector 7
Are combined at the respective positions, and then a CT image is obtained by performing a normal CT image reconstruction process. CT image data is 180 ° + α
360 ° like C-arm 5
X-ray detector 7
It is possible to capture a CT image with a larger field of view than that of the CT image.

Therefore, a CT image of a relatively large field of view can be taken by the X-ray angiography apparatus. Therefore separate X
Since there is no need to use a line CT apparatus, it is possible to reduce costs in imaging and reduce the installation area of the apparatus, so that it can be introduced in many hospital facilities.

Further, by performing the bias correction at the time of data synthesis, a step between the two data is eliminated, and it is possible to remove an artifact accompanying the data synthesis. Furthermore, a reconstructed image with less artifacts can be obtained by performing a smoothing process near a joint between both data.

<Second Embodiment> Next, an apparatus having a configuration other than the C-arm as a support arm in the present invention will be described as an example.

FIGS. 8 and 9 are a side view and a front view showing a schematic configuration of a therapeutic X-ray simulator as an X-ray fluoroscopic apparatus. Although the block diagram is omitted, the configuration is almost the same as that of FIG. 2 described above.

This apparatus originally captures an X-ray fluoroscopic image for aim collation, which is collated when aiming the radiation to be irradiated on the subject M in radiation treatment, before performing the treatment.

This device has a gantry G, in which a U-shaped support arm 45 in which an X-ray detector 7 and an X-ray source 9 are arranged opposite to each other in the vicinity of the tip can rotate about a horizontal axis. Attached to. The support arm 45 has a rotation axis A1.
Is rotatable around a range of less than 360 °.

The X-ray detector 9 is mounted via a curved linear guide 17 so as to be movable in an arc at the tip of the support arm 45. As shown in FIG. 9, the movement range is at least two positions: a first position where the imaging axis S is located on the left side of the rotation axis A1, and a second position located on the right side. Further, it is possible to move to a third position where the photographing axis S and the rotation axis A1 coincide with each other, and at this time, the original apparatus operation can be performed.

Although a description is omitted, a mechanism necessary for moving the X-ray detector 7 and a configuration for controlling the movement are the same as those in the first embodiment. Further, the X-ray source 9
The same applies to the case where the X-ray irradiation range is switched according to the movement of the line detector 7.

Even in the therapeutic X-ray simulator having such a configuration, the X-ray detector 7 is moved to the first position and the second position, and the support arm 45 is rotated about 180 ° at each position. Thereby, the same effect as in the first embodiment described above can be obtained.

In each of the above embodiments, an X-ray angiography apparatus and a therapeutic X-ray simulator have been described as examples. However, the present invention is applied to a C-arm fluoroscope and a surgical C-arm fluoroscope. Needless to say, this is also applicable.

In each of the above embodiments, the X-ray detector is described as being movable to the first position, the second position, and the third position.
, A CT image can be obtained. Further, by being configured to be able to move to more positions than the above-mentioned positions, a CT having a larger field of view can be obtained.
An image can be obtained.

[0052]

As is apparent from the above description, according to the first aspect of the present invention, the two-dimensional X-ray detector is shifted from the rotation axis by the moving means, and is rotated by the rotating means in each state. Data is collected by data collection means. Since the CT data can be reconstructed if it is 180 ° + α, even a support arm such as the C arm that can rotate only less than 360 ° can capture a CT image with a larger field of view than the X-ray detector. .

Therefore, an X-ray angiography device and a therapeutic X
C with a relatively large field of view using a device such as a line simulator
Since a T image can be taken and there is no need to use a separate X-ray CT apparatus, the cost in imaging can be reduced, and the installation area can be reduced. It is possible to introduce.

According to the second aspect of the present invention, since the X-ray irradiation range is adjusted by operating the collimator moving means, unnecessary X-ray bombardment can be suppressed.

According to the third aspect of the present invention, necessary data is collected by moving the two-dimensional X-ray detector symmetrically in two directions from the center position by the moving means and collecting data.

According to the fourth aspect of the present invention, after the data collected in a state where the two-dimensional X-ray detector is located at a different position is synthesized, a CT image reconstruction process which is generally performed Is performed, it is possible to obtain a CT image having a larger visual field than the two-dimensional X-ray detector.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of an X-ray fluoroscopic apparatus (X-ray angiography apparatus) according to a first embodiment.

FIG. 2 is a block diagram illustrating a schematic configuration of the X-ray fluoroscopic apparatus according to the first embodiment.

FIG. 3 is a diagram showing a schematic configuration of a moving mechanism.

FIG. 4 is a schematic configuration diagram of a moving mechanism.

FIG. 5 is a diagram showing a movable range of a two-dimensional X-ray detector.

FIG. 6 is a schematic diagram showing an operation of photographing a CT image.

FIG. 7 is a schematic diagram for explaining data synthesis.

FIG. 8 is an X-ray fluoroscopic apparatus (therapeutic X) according to the second embodiment.
FIG. 3 is a side view showing a schematic configuration of a (line simulator).

FIG. 9 is a front view showing a schematic configuration of an X-ray fluoroscopic apparatus according to a second embodiment.

[Explanation of symbols]

 M ... subject 1 ... bed 5 ... C arm (support arm) 7 ... X-ray detector 9 ... X-ray source 15 ... rotation drive unit S ... imaging axis A1 ... rotation axis 17 ... linear guide 31 ... rotation control unit (rotation) Means) 33 Movement control unit (movement means) 35 X-ray irradiation control unit (collimator movement means) 37 Data collection unit (data collection means) 39 Control unit (data processing means)

Claims (4)

[Claims] 1. An X-ray fluoroscopy apparatus for rotating an X-ray source and a two-dimensional X-ray detector around an object to take an X-ray fluoroscopic image, wherein the X-ray source and the two-dimensional X-ray detector face each other. Rotating means for rotating the support arm, which is provided as above, around a rotation axis at less than 360 °, moving means for moving the two-dimensional X-ray detector, and moving the two-dimensional X-ray detector by the moving means. An X-ray fluoroscopic apparatus comprising: a data acquisition unit that acquires data while driving the rotation unit at a position; and a data processing unit that reconstructs a CT image based on the acquired data. 2. The collimator moving means for moving a collimator so that only a two-dimensional X-ray detector is irradiated with X-rays in accordance with the operation of the moving means. An X-ray fluoroscopic apparatus comprising: 3. The X-ray fluoroscopic apparatus according to claim 1, wherein the moving means moves the two-dimensional X-ray detector symmetrically in two directions from a center position.
Fluoroscopy equipment. 4. The X according to claim 1, wherein
In the fluoroscopic imaging apparatus, the data processing means performs CT image reconstruction processing after synthesizing data collected by the two-dimensional X-ray detector at different positions.
Fluoroscopy equipment.