JP2006043350A - X-ray tomography apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray tomography apparatus in which a rotating X-ray photographing means is prevented from contacting a subject through a simple structure and efficiency in a photographing work is increased. <P>SOLUTION: The X-ray photographing means 12 is covered by a scanner cover 13. The scanner cover 13 is fixed to the case of a scanner driving part 5, that is, fixed to a non-rotation part. The X-ray photographing means 12 being a rotary body is rotated in a space in the scanner cover 13. The scanner cover 13 covers whole elements to be rotated due to the rotation of the X-ray photographing means 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an X-ray tomography apparatus in which an X-ray imaging means having an X-ray irradiation unit and an X-ray detector is rotated outside a subject arrangement space.

  In a conventional X-ray imaging apparatus, an X-ray source is provided at one end of a turning arm, and an X-ray detector is provided at the other end of the turning arm. And a turning arm is rotated by a rotation drive unit (for example, refer to patent documents 1).

JP 2002-219127 A

  In the conventional X-ray imaging apparatus as described above, since the scanner including the X-ray source and the X-ray detector is rotated around the subject when performing imaging, the scanner may come into contact with the subject. It was necessary to sufficiently check at the stage of photographing positioning so as not to occur. For this reason, the efficiency of photographing work is reduced.

  The present invention has been made to solve the above-described problems. With a simple structure, the rotating X-ray imaging means can be prevented from coming into contact with the subject, and the efficiency of imaging work can be improved. An object of the present invention is to obtain an X-ray tomography apparatus that can be used.

  An X-ray tomography apparatus according to the present invention includes a subject support means for supporting a subject, an X-ray source disposed above the subject support means and irradiating the subject with X-rays, and the X-ray source And an X-ray detector for detecting transmitted X-rays of the subject. The X-ray source and the X-ray detector are disposed outside the space in which the subject is placed with the body axis of the subject as a central axis. An X-ray imaging unit that is supported so as to rotate, and a cover that is disposed between a rotation space in which the X-ray imaging unit is rotated and a subject arrangement space, and prevents contact between the subject and the X-ray imaging unit. Means.

  In the X-ray tomography apparatus of the present invention, the cover means for preventing contact between the subject and the X-ray imaging means is arranged between the rotation space in which the X-ray imaging means is rotated and the subject arrangement space. With a simple structure, the rotating X-ray imaging means can be prevented from coming into contact with the subject, and the efficiency of the imaging operation can be improved.

The best mode for carrying out the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 is a block diagram showing an X-ray tomography apparatus according to Embodiment 1 of the present invention. In this example, a sitting type X-ray tomography apparatus for imaging the head and neck is shown. In the figure, a chair 2 as a subject support means on which the subject 1 sits is supported by a chair support portion 3. The chair 2 can be displaced in the vertical direction and the horizontal direction (front and rear, left and right directions) by a driving force of a chair driving device (not shown) provided in the chair support portion 3.

  A support column 4 is provided on the back of the chair support 3. A scanner driving unit 5 is supported on the column 4. The scanner driving unit 5 accommodates devices such as a motor (not shown). The scanner driving unit 5 is disposed above (directly above) the chair 2.

  A scanner arm 6 is supported on the scanner driving unit 5. The scanner arm 6 is rotated about a vertical rotation axis by the scanner driving unit 5. The extension line of the rotation axis of the scanner arm 6 is substantially coincident with the body axis of the subject 1 when sitting on the chair 2.

  An X-ray tube (X-ray source) 7 that irradiates the subject 1 with conical X-rays from the X-ray focal point is mounted on one end of the scanner arm 6. On the subject 1 side of the X-ray tube 7, a collimator 8 for limiting the X-ray range to be irradiated is provided. The X-ray irradiation unit 9 includes an X-ray tube 7 and a collimator 8.

  An X-ray detector (two-dimensional detector) 10 that detects transmitted X-rays transmitted through the subject 1 is mounted on the other end of the scanner arm 6. The X-ray detector 10 faces the X-ray irradiation unit 9 with a subject placement space 11 in which the subject 1 is placed. The X-ray detector 10 obtains fluoroscopic image data by detecting the intensity of X-rays that have passed through the subject 1. The X-ray imaging means (X-ray scanner) 12 includes an X-ray irradiation unit 9 and an X-ray detector 10, and is rotated outside the object arrangement space 11 by the scanner driving unit 5.

  The X-ray imaging unit 12 is covered with a scanner cover 13 as a cover unit. The scanner cover 13 is fixed to the housing of the scanner driving unit 5, for example, as shown in FIG. That is, the scanner cover 13 is fixed with respect to the non-rotating part. The X-ray imaging means 12 that is a rotating body is rotated in the space inside the scanner cover 13. The scanner cover 13 covers all elements that are rotated as the X-ray imaging unit 12 rotates. FIG. 1 shows a cross section of the scanner cover 13.

  The scanner cover 13 includes a cylindrical inner cover 14 as a first cover means, a cylindrical outer cover 15 as a second cover means disposed outside the inner cover 14, and an inner cover 14. And an annular bottom cover 16 that closes the bottom of the space between the outer peripheral cover 15 and an annular top cover 17 that closes the top of the space between the inner peripheral cover 14 and the outer peripheral cover 15. . The top cover 17 is provided around the scanner driving unit 5 so as to face the bottom cover 16.

  The inner peripheral cover 14 is disposed on the inner peripheral side of the X-ray imaging unit 12 along the rotational trajectory of the X-ray imaging unit 12. Further, the inner peripheral cover 14 is arranged in contact with the subject arrangement space 11. Furthermore, the inner peripheral cover 14 is made of a material that has little influence on X-ray absorption, such as acrylic. The outer peripheral cover 15 is disposed on the outer peripheral side of the X-ray imaging unit 12 along the rotation path of the X-ray imaging unit 12. That is, the outer peripheral cover 15 is disposed outside the inner peripheral cover 14 with the rotation trajectory of the X-ray imaging unit 12 interposed therebetween. Moreover, the outer periphery cover 15 is comprised by materials, such as FRP, for example. Further, as shown in FIG. 2, in order to further reduce the leakage of X-rays to the outside of the scanner cover 13, an X-ray absorber 15a such as lead is disposed on the outer peripheral cover 15 in a belt shape over the entire periphery. ing. The bottom cover 16 and the top cover 17 are also configured by, for example, FRP.

  The scanner driving unit 5 is controlled by the rotation control unit 18. The driving of the chair 2 is controlled by the chair drive control unit 19. Adjustment of the X-ray irradiation range in the collimator 8 is controlled by the collimator controller 20.

  The X-ray irradiation unit 9, the X-ray detector 10, the rotation control unit 18, the chair drive control unit 19, and the collimator control unit 20 are connected to the image processing unit 21. The image processing unit 21 stores the projection image captured by the X-ray imaging unit 12 and reconstructs a tomographic image. The image processing unit 21 includes an interface 22, a memory 23, a hard disk 24, and a CPU (arithmetic processing unit) 25. The interface 22 inputs and outputs X-ray projection images and visible light captured images, and communicates with the control units 18 to 20. The memory 23 temporarily stores image data. The hard disk 24 stores image data necessary for arithmetic processing.

  A display device 26 and an external input device 27 are connected to the image processing unit 21. An image captured by the X-ray imaging unit 12 is displayed on the display device 26. Input of information such as characters to the image processing unit 21 is performed from the external input device 27.

  Next, the operation will be described. Every time the X-ray irradiation unit 9 and the X-ray detector 10 rotate by a minute angle, X-rays are irradiated from the X-ray tube 7 and the intensity of X-rays transmitted through the subject 1 is detected by the X-ray detector 10. . When this operation is repeated for the entire circumference, 100 to several hundreds of transmitted X-ray intensity data are collected.

  The transmitted X-ray intensity data measured by the X-ray detector 10 is converted into a digital signal and then sent to the image processing unit 21. The transmitted X-ray intensity data sent from the X-ray detector 10 is temporarily stored in the memory 23 and then stored in the hard disk 24.

  When displaying a projected image, the transmission X-ray intensity data stored in the hard disk 24 is read into the memory 23 and the read data is displayed on the display device 26. Further, the image processing unit 21 executes correction of transmission X-ray intensity data, filtering processing, and three-dimensional reconstruction calculation.

  The transmission X-ray intensity data is corrected by reading the transmission X-ray intensity data stored in the hard disk 24 into the memory 23 and correcting the disturbance of the transmission X-ray intensity data caused by the sensitivity unevenness of the X-ray detector 10 by the CPU 25. In the filtering process, the entire transmitted X-ray intensity data is processed in the CPU 25 using a correction filter such as a well-known Shepp-Logan filter.

  In the three-dimensional reconstruction calculation, a three-dimensional X-ray absorption coefficient distribution in a region where the subject 1 is displayed is calculated in the CPU 25 from data obtained by performing correction and filtering. A three-dimensional reconstruction image is created by the three-dimensional reconstruction operation. As a specific example of the reconstruction calculation, there is a cone beam reconstruction calculation based on the well-known Feldkamp method.

  The three-dimensional reconstructed image can be stored in the hard disk 24 or the like. When displaying a three-dimensional reconstructed image, the three-dimensional reconstructed image stored in the hard disk 24 or the like is read to the memory 23 and the data read to the memory 23 is displayed on the display device 26. Further, the three-dimensional reconstructed image stored in the hard disk 24 is read out to the memory 23, and the CPU 25 performs a reprojection calculation to create a three-dimensional reprojected image.

  The three-dimensional reprojection image can be stored in the hard disk 24 or the like. When displaying a three-dimensional reprojection image, the three-dimensional reprojection image stored in the hard disk 24 or the like is read to the memory 23 and the data read to the memory 23 is displayed on the display device 26.

  In such an X-ray tomography apparatus, the scanner cover 13 fixed with respect to the non-rotating part is arranged around the subject arrangement space, and the X-ray imaging means 12 which is a rotating body is provided in the scanner cover 13. Therefore, with a simple structure, the rotating X-ray imaging means 12 can be prevented from coming into contact with the subject 1, and the efficiency of the imaging operation can be improved.

In addition, since the outer cover 15 is provided on the scanner cover 13, contact with devices and people located outside the X-ray imaging means 12 can be easily avoided.
Furthermore, since the inner peripheral cover 14 is made of a material that has little influence on the absorption of X-rays, it is possible to prevent a decrease in X-ray detection accuracy due to the provision of the scanner cover 13. Furthermore, since the X-ray absorber 15a is provided on the outer cover 15, the X-ray leakage to the outside of the scanner cover 13 can be efficiently reduced.

Embodiment 2. FIG.
Next, FIG. 3 is a block diagram showing a main part of an X-ray tomography apparatus according to Embodiment 2 of the present invention. In this example, the lower end portions of the X-ray imaging means 12 and the scanner cover 13 are located below the upper end portion of the chair 2. That is, at the initial stage when the subject 1 sits on the chair 2, the X-ray imaging means 12 and the scanner cover 13 are located above the subject 1. At the time of X-ray imaging, the chair 2 is moved to an imaging position higher than that in FIG. 3, and the subject 1 is arranged in the subject arrangement space. Further, after X-ray imaging, the chair 2 is returned to the initial position in FIG. That is, the chair 2 is movable between an initial position below the X-ray imaging unit 12 and the scanner cover 13 and an imaging position above the initial position. Other configurations are the same as those in the first embodiment.

  In such an X-ray tomography apparatus, movement of the subject 1 to the chair 2 can be facilitated even if the entire circumference of the subject arrangement space is surrounded by the scanner cover 13.

  Although the chair 2 can be moved up and down in the above example, the X-ray imaging unit 12 and the scanner cover 13 may be moved up and down between the initial position and the imaging position below the initial position.

Embodiment 3 FIG.
Next, FIG. 4 is a block diagram showing a main part of an X-ray tomography apparatus according to Embodiment 3 of the present invention. The scanner cover 13 of the third embodiment has an inner peripheral cover 14, but the outer peripheral cover 15, the bottom cover 16, and the top cover 17 as shown in the first and second embodiments are omitted. The rotating shaft 5 a of the scanner arm 6 protruding downward from the scanner driving unit 5 is fixed to the non-rotating part and penetrates the scanner arm 6. The scanner cover 13 is supported and fixed, for example, at the lower end of the rotating shaft 5a. Other configurations are the same as those in the second embodiment.

As described above, even when the scanner cover 13 having only the inner peripheral cover 14 is used, the X-ray imaging unit 12 can be prevented from coming into contact with the subject 1 while further simplifying the structure.
Further, by using a transparent material for the inner peripheral cover 14 such as acrylic, it is possible to reduce the feeling of obstruction that the scanner cover 13 gives to the subject 1.

Embodiment 4 FIG.
5 is a perspective view showing a scanner cover of an X-ray tomography apparatus according to Embodiment 4 of the present invention. The scanner cover 13 of the fourth embodiment is provided with an opening 13a. The opening 13 a is provided in a part of the scanner cover 13 in the circumferential direction. Specifically, the opening 13a is disposed so as to be positioned in front of the chair 2 (FIG. 1), that is, in front of the subject 1. Other configurations are the same as those in the first embodiment.

  In such an X-ray tomography apparatus, since the opening 13a is provided in the scanner cover 13, the feeling of obstruction given to the subject 1 can be reduced. Moreover, the movement of the subject 1 to the chair 2 can be facilitated.

Embodiment 5. FIG.
6 is a perspective view showing a scanner cover of an X-ray tomography apparatus according to Embodiment 5 of the present invention. The scanner cover 13 of the fifth embodiment is provided with an opening / closing door 31 for opening and closing the opening 13a. FIG. 7 is a perspective view showing a state in which the opening 13a of FIG.

  In such an X-ray tomography apparatus, the opening 13a is opened when the subject 1 moves to the chair 2 (FIG. 6), and the opening 13a is closed by the door 31 during X-ray imaging (FIG. 7). ). Further, when the subject 1 moves away from the chair 2 after imaging, the opening 13a is opened again. Therefore, the movement of the subject 1 to the chair 2 can be facilitated, and leakage of X-rays during imaging can be prevented.

Embodiment 6 FIG.
Next, FIG. 8 is a block diagram showing the main part of an X-ray tomography apparatus according to Embodiment 6 of the present invention, and FIG. 9 is a perspective view showing the scanner cover 13 of FIG. The scanner cover 13 of the sixth embodiment further includes a lower cover 32 that is provided below the outer peripheral cover 15 and surrounds the lower part of the subject arrangement space 11. That is, the entire periphery of the subject 1 is covered by the scanner cover 13.

  The lower cover 32 is provided with an opening 32a. The opening 32 a is provided in a part of the scanner cover 13 in the circumferential direction. Specifically, the opening 13a is disposed so as to be positioned in front of the chair 2 (FIG. 1), that is, in front of the subject 1. The scanner cover 13 is provided with an opening / closing door 33 that opens and closes the opening 32a. FIG. 10 is a perspective view showing a state in which the opening 32a of FIG. Other configurations are the same as those in the second embodiment.

In such an X-ray tomography apparatus, since the lower cover 32 is provided on the scanner cover 13, the entire periphery of the subject 1 can be covered, and X-ray leakage can be prevented more reliably.
Since the scanner cover 13 is provided with the opening 32a and the opening / closing door 33, the movement of the subject 1 to the chair 2 can be facilitated, and leakage of X-rays during imaging can be prevented. .

It is a block diagram which shows the X-ray tomography apparatus by Embodiment 1 of this invention. It is a perspective view which shows the scanner cover of FIG. It is a block diagram which shows the principal part of the X-ray tomography apparatus by Embodiment 2 of this invention. It is a block diagram which shows the principal part of the X-ray tomography apparatus by Embodiment 3 of this invention. It is a perspective view which shows the scanner cover of the X-ray tomography apparatus by Embodiment 4 of this invention. It is a perspective view which shows the scanner cover of the X-ray tomography apparatus by Embodiment 5 of this invention. It is a perspective view which shows the state which closed the opening part of FIG. 6 with the opening / closing door. It is a block diagram which shows the principal part of the X-ray tomography apparatus by Embodiment 6 of this invention. It is a perspective view which shows the scanner cover of FIG. It is a perspective view which shows the state which closed the opening part of FIG. 9 with the opening / closing door.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Subject, 2 Chair (Subject support means), 9 X-ray irradiation part, 10 X-ray detector, 11 Subject arrangement space, 12 X-ray imaging means, 13 Scanner cover (cover means), 14 Inner peripheral cover ( (First cover means), 15 outer peripheral cover (second cover means), 15a X-ray absorber.

Claims (3)

Subject support means for supporting the subject;
An X-ray source disposed above the subject support means and irradiating the subject with X-rays, and an X-ray detector disposed opposite to the X-ray source and detecting transmitted X-rays of the subject. X-ray imaging means for supporting the X-ray source and the X-ray detector so as to rotate outside a space in which the subject is arranged with the body axis of the subject as a central axis;
The X-ray imaging unit includes a cover unit that is disposed between a rotation space in which the X-ray imaging unit is rotated and the subject arrangement space, and prevents contact between the subject and the X-ray imaging unit. X-ray tomography device.   The cover means includes first cover means arranged in contact with the subject arrangement space, and second cover means arranged outside the first cover means with a rotation trajectory of the X-ray imaging means interposed therebetween. The X-ray tomography apparatus according to claim 1, wherein   The X-ray tomography apparatus according to claim 2, wherein an X-ray absorber is disposed over the entire circumference of the second cover means.

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