JP2001017419A - Tomograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tomograph simplified in mechanism and structure, facilitating action control, and capable of being manufactured at a low cost. SOLUTION: An X-ray tube 11 and a collimator 12 are fitted to one end of a rocking lever 13 in this device, and the rocking lever 13 is rocked around a point 15 by a driving device 14 to move the X-ray tube 11 and collimator 12 to a position B from a position A. The image data indicating the radiolucent image of a subject 21 at each position of movement are obtained from a fixed flat panel type X-ray sensor 24 and fed to an image processing device 31, and these images are added while being displaced based on the rocking angle information obtained from the driving device 14 to reconstitute a tomographic image on a tomographic plane 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray tomography apparatus used for medical diagnosis and the like.

[0002]

2. Description of the Related Art In the field of medical X-ray diagnosis, X-ray tomography using an X-ray film has been conventionally performed. In this X-ray tomography method, multiplexing is performed while moving the X-ray tube and the X-ray film in opposite directions with respect to a subject sandwiched therebetween so that the center of the X-ray beam always coincides with the center of the X-ray film. Expose. In recent years, electronic image data has been captured and reconstructed (added) using an image intensifier and a TV imaging system in place of X-ray film
As a result, a technique called digital tomography, which obtains the same tomographic image as obtained by multiple exposure on a film, has also emerged.

[0003]

However, in the conventional X-ray tomography apparatus, regardless of whether an X-ray film is used as an imaging system or a combination of an image intensifier and a TV camera, imaging is performed in any case. It is necessary to move the system in the opposite direction in accordance with the movement of the X-ray tube.
There is a problem that the structure and its operation control are complicated.

[0004] In view of the above, an object of the present invention is to provide an X-ray tomography apparatus which requires only a simple mechanism / structure and operation control and can be manufactured at low cost.

[0005]

In order to achieve the above object, in an X-ray tomography apparatus according to the present invention, an X-ray irradiator for irradiating an object with X-rays, A flat panel X-ray detector fixed to face the X-ray irradiator, a moving device for moving the X-ray irradiator, and subject X-ray image data obtained from the X-ray detector, An image processing apparatus is provided which reconstructs a tomographic image on a predetermined plane in the subject by adding while shifting the position based on the X-ray irradiation angle information obtained from the moving apparatus. .

The X-ray irradiator is moved, and image data based on X-rays transmitted through the subject is obtained from the X-ray detector at each position, that is, at each irradiation angle with respect to the subject. Since the image data is shifted and added based on the irradiation angle, the tomographic image is reconstructed as if multiple exposure were performed while shifting the X-ray film. In this case, the X-ray detector is a flat panel type two-dimensional X-ray detector, and a large-area X-ray detector can be easily obtained. Therefore, the X-ray detector does not need to be moved and can be kept fixed. . The X-ray detector is a flat panel type two-dimensional X-ray detector, and a large-area X-ray detector can be easily obtained. Can be reconstructed. Since the X-ray detector is fixed, only the X-ray irradiator needs to be moved, so that the mechanism, structure and operation control are simple, and the entire X-ray tomography apparatus can be manufactured at low cost.

Further, the X-ray image data transmitted through the subject from the X-ray detector is taken in by a fixed area while being substantially displaced based on the X-ray irradiation angle information obtained from the moving device, and stored by a storage device. Then, the image data stored in the storage device is read out and added by the image processing device to reconstruct a tomographic image on a predetermined plane in the subject.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings. The X-ray tomography apparatus according to the present invention is configured as schematically shown in FIG. In FIG. 1, an X-ray beam generated from an X-ray tube 11 is narrowed and radiated through a collimator 12. The X-ray tube 11 and the collimator 12 are held at one end of a swing lever 13. The swing lever 13 is driven to swing (rotate) around a center 15 by a driving device 14. This swing lever 13
X-ray tube 11 and collimator 12
Moves from the position A to the position B in FIG.

On the other hand, a subject 21 is placed on an examination table 23. An X-ray beam emitted from the X-ray tube 11 via the collimator 12 is irradiated toward the subject 21. The tomographic plane (surface on which a tomographic image is desired to be obtained) 22 set in the subject 21 has substantially the same height as the rotation center 15 of the swing lever 13.

On the examination table 23, a flat panel X-ray sensor 24 is fixed to the examination table 23 below the subject mounting top plate. The X-ray beam applied to the subject 21 passes through the subject 21 and the flat panel X-ray sensor 2
X-ray tube 11 and collimator 12
The flat panel X-ray sensor 24 is arranged at a position facing the subject 21 with the subject 21 interposed therebetween.

The flat panel type X-ray sensor 24 detects an X-ray image by an X-ray beam transmitted through the subject 21, converts the X-ray image into an electric signal, and outputs it as image data. Although not shown, this flat panel X-ray sensor 2
Reference numeral 4 denotes an X-ray conversion layer for converting incident X-rays into electric charges or light, and detection elements for detecting the electric charges or light generated in the X-ray conversion layer, which are two-dimensionally arranged vertically and horizontally in a matrix. It has a structure in which a detection array layer is laminated.

Since the flat panel type X-ray sensor 24 has such a structure, a large-sized X-ray sensor can be easily obtained.
cm × 90 cm, and the matrix configuration of the detection array layer can be, for example, about 1000 × 3000. In FIG. 1, the flat panel X-ray sensor 24 is arranged so that the longitudinal direction (lateral direction) is the left-right direction (lateral direction) in the figure. That is, the X-ray tube 11
When the collimator 12 moves from the position A to the position B in the drawing, an X-ray beam from any position enters, and an image signal of an X-ray transmission image from any angle is obtained. The flat panel type X-ray sensor 24 is configured so as to have a long dimension in the moving direction.

Image data output from the flat panel type X-ray sensor 24 is sent to an image processing device 31 where it is stored and subjected to addition processing. This image processing device 31
Includes a CPU 32, an image storage memory 33, and an adder 34 for performing an image addition process. The signal of the image obtained by the image processing device 31 is sent to the image display device 35, and the image is displayed.

The X-ray tube 11 according to the swing of the swing lever 13
When the collimator 12 moves from the position A to the position B, the image data obtained at each position of the moving stroke is
It is taken into the memory 33 under the control of the CPU 32. That is, as shown in FIG. 2, the center of the irradiated X-ray beam moves to 41, 42,..., 4n with respect to the X-ray incident surface 40 of the flat panel X-ray sensor 24 according to the movement. Therefore, the respective beam centers 41, 42,..., 4n
The flat panel X-ray sensor 2 is arranged such that regions 51, 52,.
4 is controlled by the CPU 32, and the read image data is sequentially stored in the memory 33. The reading areas 51, 52,..., 5n substantially match the X-ray beam irradiation field moving at intervals of the interval d, that is, the X-ray transmission image area.

The irradiation X-ray beam centers 41, 42,.
The position of 4n and the movement amount d are determined by the CPU 32 based on the angle information of the swing lever 13 obtained from the driving device 14 and the distance between the swing center 15 and the X-ray focal point and the swing center 15 which are known in advance.・ Flat panel type X-ray sensor 24
Is calculated according to the distance between the X-ray incidence planes.

In this way, the reading areas 51, 5
When the image data of 2,..., 5n can be stored, the CPU
Under control of 32, these images are added by the adder 34. Then, the image on the tomographic plane 22 at the height of the swing center 15 is always at the center of the reading areas 51, 52,. .., 5n are read areas 51, 52,.
Since the positions appear differently in each of them, the addition causes blurring, and the image on the tomographic plane 22 is reconstructed. The reconstructed tomographic image is displayed by the image display device 35.

If the images obtained at the respective positions of the movement of the X-ray tube 11 and the collimator 12 are shifted according to the shift amount d and added, the tomographic image having the height of the swing center 15 can be obtained. Since the tomographic image on the plane 22 can be reconstructed, not only the reading area itself of the flat panel type X-ray sensor 24 is controlled as described above to take in the image data shifted from the beginning, but also You may make it add and shift | deviate. As shown in FIG. 3, a flat panel X-ray sensor 2
4 is stored in the memory 3.
3 and the entire image data is added to the adder 34.
, The irradiation X-ray beam centers 41, 42,.
If the addition is performed while shifting the position by the position shift amount d of 4n, the tomographic image on the tomographic plane 22 at the height of the swing center 15 can be reconstructed in the same manner as described above.

A driving device 1 for rotationally driving the swing lever 13
Reference numeral 4 indicates that the height of the rotation center 15 can be arbitrarily changed. By changing the height of the rotation center 15, a tomographic image of the tomographic plane 22 having a height corresponding to the height can be obtained. it can. In the above description, the process of superimposing and adding images is performed by the adder 34.
Similar processing can be performed by software by the CPU 32. Further, in the above, the X-ray tube 11 and the collimator 12 are moved so as to draw a linear trajectory when viewed from a direction perpendicular to the X-ray incident surface of the flat panel type X-ray sensor 24 to perform a so-called linear tomography. However, when viewed from the same direction, a so-called multi-orbit tom that moves so as to draw a two-dimensional trajectory such as a circular shape or a spiral shape also causes the X-ray incident surface of the flat panel X-ray sensor 24 to move in the vertical direction ( It can be applied by enlarging in a direction perpendicular to the plane of FIG.

[0019]

As described above, according to the X-ray tomography apparatus of the present invention, a flat panel type X-ray sensor which can easily make the X-ray incident surface large is used as the imaging system. In the case of a combination of an image intensifier and a TV camera or an imaging system using an X-ray film, the imaging system is inevitable in synchronization with the movement of the X-ray tube. Can remain fixed. Therefore, the mechanism and structure are simplified, the operation control is facilitated, and the device can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a relationship between an X-ray incident surface of a flat panel X-ray sensor and an image reading area.

FIG. 3 is a schematic diagram illustrating a positional shift of an irradiation X-ray beam center with respect to an X-ray incidence surface of a flat panel X-ray sensor.

[Explanation of symbols]

REFERENCE SIGNS LIST 11 X-ray tube 12 collimator 13 swing lever 14 drive device 15 swing center 21 subject 22 tomographic plane 23 examination table 24 flat panel X-ray sensor 31 image processing device 32 CPU 33 memory 34 adder 35 image display device 40 flat X-ray incident surface 41, 41,..., 4n of panel type X-ray sensor Irradiated X-ray beam center 51, 52,.

Claims (2)

[Claims] An X-ray irradiator for irradiating an object with X-rays,
A flat panel X-ray detector fixed so as to face the X-ray irradiator with a subject interposed therebetween, a moving device for moving the X-ray irradiator, and a subject obtained from the X-ray detector An image processing apparatus that reconstructs a tomographic image on a predetermined plane in the subject by adding transmission X-ray image data while substantially displacing the positions based on the X-ray irradiation angle information obtained from the moving device. An X-ray tomography apparatus comprising: 2. An X-ray irradiator for irradiating a subject with X-rays,
A flat panel X-ray detector fixed to face the X-ray irradiator with a subject interposed therebetween; a moving device for moving the X-ray irradiator; Adding a storage device that captures and stores line image data by a certain area while substantially displacing the position based on the X-ray irradiation angle information obtained from the moving device, and adding the image data stored by the storage device And an image processing device for reconstructing a tomographic image on a predetermined plane in the subject.