JP4574661B2 - X-ray CT system - Google Patents

Description

  The present invention relates to an X-ray CT apparatus that rotates and irradiates an object to be inspected with an X-ray beam and processes a projection image thereof to take a tomographic image or the like, and in particular, an X-ray cone beam is applied to a part of the object. The present invention relates to an X-ray CT apparatus suitable for use in imaging for dentistry that can be irradiated to obtain an arbitrary CT tomographic image and panoramic image of the portion.

  Dental care is a general radiographing film with a film on the back of the teeth, panoramic radiographing by rotating the X-ray tube and the film at the same time, and a cefaro radiographing taking a large distance between the X-ray tube and the film. The current situation is that the images taken by the above are used. Dental X-ray panoramic radiographing continuously captures a curved tomographic image along the dentition, and develops a tomographic image showing the dentition and the surrounding tissue and bone in a single panoramic image. To display.

  In a conventional panoramic imaging apparatus, a swivel arm equipped with an X-ray generation device and a two-dimensional X-ray detection device facing each other with a subject interposed therebetween is supported by, for example, front and rear, left and right moving units and a rotating unit, and around the subject The movement was controlled by drawing a complicated trajectory that approximated the shape of the dental arch. As a conventional technique related to such a panoramic photographing apparatus, for example, a technique described in Patent Document 1 is known.

  Further, as a dental X-ray imaging apparatus, an X-ray imaging apparatus having a CT function for obtaining a cross-sectional image of a tooth other than a panoramic imaging apparatus is known, for example, described in Patent Document 2 and the like. A panoramic X-ray imaging apparatus capable of performing X-ray CT imaging is also described, for example, in Patent Document 3 and the like.

  Further, as a conventional technique related to X-ray CT imaging that enables an X-ray cone beam to be irradiated only to a part of a subject and to obtain an arbitrary tomographic screen, stereoscopic image, or panoramic image of that part, for example, Patent Document The technique described in 4 etc. is known.

  This prior art device reduces the exposure of the subject by turning and irradiating the X-ray cone beam limited to the area around the teeth and temporomandibular joint, not the entire jaw including the dental arch. In addition, a high-resolution CT tomographic image and a three-dimensional stereoscopic image can be obtained.

  The above-described conventional dental panoramic imaging apparatus or dental CT apparatus is for imaging a subject in a standing position or a sitting position, and both have a structure in which the rotation drive unit is present on the head of the subject. I am doing.

  FIG. 8 is a diagram showing a basic structure example of a sitting type X-ray CT apparatus according to the prior art. Hereinafter, the X-ray CT apparatus according to the prior art will be controlled with reference to FIG. In FIG. 8, 801 is a fixed base, 802 is a rotating unit, 803 is an X-ray generator, 803a is an X-ray source, 803b is an X-ray cone beam, 804 is an X-ray detector, 805 is a rotating shaft, and 807 is a test object. 808 is a chair, 809 is a head receiving device, 810 is a control device, 811 is an image processing device, and 812 is an image display device.

  The X-ray CT apparatus according to the prior art shown in FIG. 8 is an X-ray generation apparatus in which a rotating unit 802 is suspended from a fixed base 801 and is above the subject 807 sitting on a chair 808 and held by the rotating unit 802. 803 and the X-ray detection apparatus 804 are configured to be rotated by the control apparatus 10 along the rotation axis 805 around the subject 807. The head of the subject 807 is fixed to the chair 808 by a head support 809.

In the above description, the X-ray cone beam emitted from the X-ray source 803a of the X-ray generator 803 passes through the imaging region of the subject 807 and is detected as image data by the X-ray detector 804. Image data collected from the two-dimensional X-ray detection apparatus 804 is sent to the image processing apparatus 811. The image processing device 811 performs arithmetic processing on the received image data, reconstructs a two-dimensional tomographic image, CT image, or three-dimensional stereoscopic image, and displays it on the image display device 812.
Japanese Patent Laid-Open No. 06-78919 JP 09-122118 A JP 11-318886 A JP 2000-13902 A

  In the above-described conventional technology, the height of the device is necessarily higher than the height of the subject 807, and in any case, the height of the device exceeds 2 meters. The dental X-ray imaging apparatus is as small and light as possible because the space for installing the apparatus and the space for carrying in the apparatus are often limited as compared with a general diagnostic X-ray imaging apparatus. desirable. However, if the device according to the prior art is intended to reduce the height, the head of the operator or the head of the operator who performs operations such as position setting and confirmation of the subject around the subject There is a problem that the distance in the height direction from the apparatus is reduced, and the risk that the head of the subject or the operator collides with the apparatus increases.

  Further, in the case of an upright type apparatus, the rotating part of the apparatus can be retracted in the height direction in order to avoid the risk of the head colliding with the apparatus as described above. Such a sitting-type device has a high risk of collision between the head and the device during the standing-up operation when the subject gets on and off the chair of the device. In addition, the sitting-type device needs to change the height of the measuring unit of the device or the subject according to the height of the patient, but when adjusting the height of the device or the patient, for example, due to an erroneous operation or the like. The subject's head and the device may collide.

  In addition, the space below the rotating part of the device is a free space. At first glance, it seems safe without the rotating part, but it is possible for a subject, an operator, or a maintenance worker of the device to enter the rotating part. Therefore, if the face is carelessly raised in this state, the head and the device may collide. As described above, the device according to the prior art may cause a subject, an operator, or another operator to enter the above-described free space even when the device is in a stationary state, and there is a risk of collision with the device. Has the problem that it will always exist.

  In particular, in the case of a dental X-ray CT apparatus, imaging may be performed during surgery on the temporomandibular joint or the like. Such imaging is called intraoperative imaging (IVR: Interventional Radiology). In the case of this intraoperative imaging, it is important that the operator can easily approach the affected area of the subject, and it goes without saying that the safety of both the subject and the operator must be sufficiently ensured.

  In addition, since the apparatus according to the prior art has a closed space in the vicinity of the subject's head, the top, bottom, back and forth, or left and right, the subject can feel a feeling of pressure or obstruction by the apparatus. It has a great psychological impact.

  On the other hand, in view of the installation space of the device, in order to install the rotating part above the subject's head, it is generally against the floor where the device is installed, except when the device is fixed to the ceiling. It is necessary to install a column (such as the fixed mount 801 in FIG. 1) that supports the rotating unit. For this reason, the apparatus by a prior art also has the problem from the installation surface that the area which installs a support | pillar part is needed in the installation space of an apparatus other than the area which a rotation part occupies.

  An object of the present invention is to provide an X-ray CT apparatus capable of improving safety and reducing the height and installation space of the apparatus as much as possible.

The object according to the present invention rotates irradiated with X-ray beams to the subject, in the X-ray CT apparatus for photographing the projected image, and chair is supported by the base to be installed on a floor surface subject, the subject A column connecting unit disposed under the chair for use and rotatably attached to the base via a rotation drive mechanism unit, and an X-ray generator coupled to the column connecting unit so as to sandwich the subject chair. The X-ray generating means for generating the X-ray beam and the X-rays transmitted through the subject, which are attached to the X-ray generating means and the X-ray detecting means prop An X-ray detection means for detecting an image, and the rotation driving mechanism unit rotates the column connecting portion to sandwich the X-ray generation means and the X-ray detection means between the fixed subject chair . Rotating with More is achieved.

  As described above, according to the present invention, safety can be improved, and the height and installation space of the apparatus can be greatly reduced.

  Hereinafter, embodiments of an X-ray CT apparatus according to the present invention will be described in detail with reference to the drawings.

  1 is a perspective view seen from the front side of an X-ray CT apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view seen from the rear side of an X-ray CT apparatus according to an embodiment of the present invention. FIG. 4 is a front view of an X-ray CT apparatus according to an embodiment of the present invention, FIG. 4 is a side view of a subject on the X-ray CT apparatus according to an embodiment of the present invention, and FIG. It is a top view in the state where the subject got on the X-ray CT apparatus by an embodiment. 1 to 5, 101 is a floor surface, 102 is a mat, 103 is a step, 104 is an X-ray generator, 105 is an X-ray imager, 106 is an X-ray generator column, and 107 is an X-ray imager. Support column, 108 is a support connecting part, 109 is a footrest, 110 is a chair base, 111 is a chair back, 112 is an armrest, 113 is a chair seat surface part, 114 is a foot guard, 115 is a head fixing device, 116 Is a jaw fixing device, 117 is a head and a column for the jaw fixing device, 118 is a power supply box, and 119 is a handle.

  As shown in FIGS. 1 to 5, an X-ray CT apparatus according to an embodiment of the present invention has an X-ray supported on a support 106 for an X-ray generator on a circular mat 102 provided on a floor surface 101. The generator 104 and the X-ray imaging apparatus 105 supported by the X-ray imaging apparatus support column 107 are arranged so as to face each other with the head of the subject as the subject interposed therebetween. The support column 106 for the X-ray generator and the support column 107 for the X-ray imaging device are connected to each other by a support connecting portion 108 at a lower portion thereof, and the substantially center position of the support connecting portion 108, that is, the approximately center position of the mat 102 is supported. As shown in FIG.

  The chair on which the subject is seated at the time of photographing is not rotated on the support column connecting portion 108 with respect to the rotation of the X-ray generation device 104 and the X-ray imaging device 105 that rotate together with the support column connecting portion 108. And it is installed so that it can be moved up and down. This chair includes a chair seat surface portion 113 having an armrest 112 on which a subject is seated, a chair pedestal portion 110, and a chair backrest 111 connected to the rear surface of the pedestal portion 110. The front side of the chair pedestal portion 110 is configured to have a member that is one step lower and protrudes in a circular shape forward. This member is provided with an arc-shaped plate-like foot guard 114 that can move along the circular circumferential portion. In addition, a footrest 109 that slides back and forth so as to be housed in the chair pedestal 110 is provided at a position one step lower on the front side of the chair pedestal 110.

  The chair back 111 is formed in an arc shape along the rotation trajectory between the X-ray generator support column 106 and the X-ray imaging device support column 107 so that the doctor can examine the subject. When approaching the apparatus during imaging, the rotational range of the X-ray generation apparatus support column 106 and the X-ray imaging apparatus support column 107 can be visually recognized. Thereby, an accident can be prevented and an X-ray CT apparatus that is safe for a doctor or the like can be provided.

  Further, the chair pedestal 110 is provided with a head and chin fixing device support column 117, which is held in the vertical direction so that the head of the subject does not move during X-ray imaging. A head fixing device 115 and a chin fixing device 116 that can be moved and fixed to the chin are attached. The chair seat surface portion 113 is slidable forward and backward, and a handle 119 for raising and lowering the seat surface portion is provided at the lower portion thereof. By manually turning the handle 119, the chair seat surface portion 113 can be moved up and down. The position and height of the chair seat surface 113 can be adjusted according to the height and seat height of the subject by adjusting the position of the chair seat surface 113 by sliding back and forth and adjusting the height by the handle 119. The height adjustment can be performed by electric drive.

  Further, a step 103 is connected before and after the column connecting portion 108, and a power supply box 118 formed in a substantially triangular prism shape is installed outside the circular mat 102. Step 103 is used as a stair when the subject sits on the chair seat surface 113 of the X-ray CT apparatus. When the subject places his / her foot on the mat 102, Can work safety device.

  The chair back 111 constituting the chair is formed in a semi-cylindrical shape as can be seen from the perspective view shown in FIG. 2, and a control device for the X-ray generator 104 and the X-ray imaging device 105 is shown therein. A communication unit that performs communication with the image processing apparatus, the image display apparatus, and the like that are not included is housed. In the embodiment to be described, the power supply box 118 is provided separately. However, the power supply unit may be provided in the interior of the chair back 111 and the power back may be provided in the chair back 111.

  In the figure showing the configuration of the X-ray CT apparatus according to the embodiment of the present invention having the above-described configuration, the floor surface 101 is shown squarely, which is the minimum installation of the X-ray CT apparatus according to the embodiment of the present invention. It shows an area and is approximately 1800 mm × 1800 mm in size, and the above-mentioned power supply box 118 is also arranged inside this. That is, the X-ray CT apparatus according to the embodiment of the present invention can be stored in a small room having a size of 1800 mm × 1800 mm.

  The illustrated X-ray CT apparatus is installed on a circular mat 102 having a diameter of 1640 mm provided on the floor surface 101. The circular mat 102 allows the inside of the mat 102 to be inside the X-ray generator 104. Since the rotation region between the X-ray imaging apparatus 105 and the X-ray imaging apparatus 105 can be visually clarified, the patient can be visually alerted to a doctor or the like to prevent an accident. The mat 102 is provided with a safety device having a pressure sensor or the like inside. When a subject, a doctor, or the like gets on the mat 102, the support 106 for the X-ray generator. In addition, the rotation of the support 107 for the X-ray imaging apparatus is stopped or is prevented from rotating even if it is erroneously rotated. Thus, when a person enters the rotation trajectory of the X-ray generator support column 106 and the X-ray imaging device support column 107, the rotation of the X-ray generation device support column 106 and the X-ray imaging device support column 107 is stopped. Accidents can be prevented beforehand.

  Next, an operation when the subject is seated on the X-ray CT apparatus according to the embodiment of the present invention configured as described above will be described.

  Before the subject is seated, the X-ray generator 104 and the X-ray imaging device 105 are moved so as to be positioned on both sides of the chair on which the subject is seated, as shown in a front view in FIG. The foot guard 114 is retracted to the side. Further, the head fixing device 115 and the chin fixing device 116 are moved to the side as shown in FIG. 2 from the front position shown in FIG.

  In the state as described above, the subject is seated on the seat surface portion 113 of the chair from the front side of the apparatus. At this time, the subject advances from the floor surface 101 to the mat 102, step 103, the lower part of the chair base 110, and the footrest 109 in order to be seated on the chair seat surface 113. As described above, the safety device is incorporated in the mat 102, and the step 103 is in contact with the mat 102 when a person puts his / her foot on, so that the safety device is operated. Can sit on. After the subject is seated, a doctor, an engineer, etc. adjusts the front / rear position of the chair seat surface portion 113, adjusts the height of the chair seat surface portion 113 using the handle 119, and moves the footrest base 109 back and forth. The patient's feet are easily placed on the platform 109.

  Furthermore, a doctor, an engineer, etc. move the head fixing device 115 and the chin fixing device 116 to the front, and adjust the height to fix the head and chin of the subject. The position of the subject's head needs to be a position where an imaging region such as a tooth is irradiated with X-rays from the X-ray generation device 104 to reach the X-ray imaging device 105. The adjustment of the height of the seating surface 113 and the adjustment of the heights of the head fixing device 115 and the chin fixing device 116 are repeated. Thereafter, the doctor, the engineer, and the like place the foot guard 114 in front and finish the preparation for photographing. The reason why the foot guard 114 is positioned in front is that the X-ray generator support column 106 and the X-ray imaging device rotate during imaging when the subject inadvertently throws his / her foot forward. This is for avoiding a danger that a foot is put on the support column 107. Further, since the outer periphery of the foot guard 114 is formed in an arc shape along the rotation trajectory of the X-ray generator support column 106 and the X-ray imaging device support column 107, each of the above-mentioned items can be obtained when the subject sits down on the chair. The rotation range of the columns 106 and 107 can be visually clarified, and a sense of security can be given to the subject.

  When the subject descends from the X-ray CT apparatus, the subject performs the reverse operation to that described above. In this case as well, after the subject places his / her foot on step 103, the subject erroneously operates. Since the X-ray generator support column 106 and the X-ray imaging device support column 107 do not rotate, it is possible to descend safely.

  As already described, the step 103 is provided in front of and behind the support column connecting portion 108, so that the X-ray generation device 104 and the X-ray imaging device 105 are located on either side of the subject. Sometimes, when the subject can get on and off the apparatus, and when the X-ray generator 104 and the X-ray imaging device 105 are positioned before and after the subject, two steps 103 are performed on the subject. It will be located on both sides, and a doctor or the like can take the step 103 at this position and access the subject from the side of the subject to perform treatment or the like. The step 103 is slightly larger than the width of the chair. This step 103 is a step when the subject sits on the chair, and guides the direction from which the subject sits on the chair from the outside of the apparatus. In addition, a space is formed on both sides of the step 103, so that the exposed surface of the mat 102 in which a safety device that is not significantly different from the floor surface 101 is incorporated can be formed widely. When the device must be stopped urgently, the device can be stopped even if the rotating device is not so close.

  FIG. 4 shows the situation of the side face when the subject is seated on the chair seat surface 113 of the X-ray CT apparatus, the position is adjusted, and the head is fixed, and the situation seen from the top is shown in FIG. . FIG. 4 shows a state in which the X-ray imaging device 105 is removed in a state where the X-ray generation device 104 and the X-ray imaging device 105 are located on the side of the subject. In such a state, the X-ray generator support column 106 and the X-ray imaging device support column 107 are rotated together with the support column connecting portion 108, and the X-rays from the X-ray generator 104 are applied to the imaging region of the subject. The irradiated and transmitted X-rays reach the X-ray imaging apparatus 105, and an image of a tooth or the like can be obtained from the X-ray imaging apparatus 105.

  Whether the X-ray generation device 104 and the X-ray imaging device 105 at the time of imaging are tomographic images or panoramic images, rather than being rotated around a single axis in a complete circle Thus, while changing the center of rotation, it is controlled and rotated so that the imaging region can always be imaged most clearly. Since this rotation control is not the gist of the present invention, a description thereof is omitted here.

  FIG. 6 is a diagram for explaining the rotation drive mechanism of the X-ray generator and X-ray imaging apparatus and the lift drive mechanism of the chair seat surface portion. In FIG. 6, 120 is a rotation drive mechanism, 121 is an elevating drive mechanism, 122 is a rotation shaft, 123 is a chair seat surface support column, 124 is a base, and other reference numerals are the same as those in FIGS. It is.

  The example shown in FIG. 6 shows a cross section viewed from the side in a state where each of the X-ray generation device 104 and the X-ray imaging device 105 is positioned in front of and behind the subject's head, The example at the time of making it raise / lower the chair seat surface part 113 electrically is shown.

  As shown in FIG. 6, the X-ray generator 104 and the X-ray imaging device 105 supported by the respective columns 106 and 107 and the column coupling unit 108 that couples them are arranged at the lower part of the mat 102. Is supported by a rotating shaft 122 and installed on a base 124 provided on the base plate. The rotating shaft 122 is formed in a hollow pipe shape having a certain thickness, and a chair seat surface portion supporting column 123 is supported by the base 124 through the inside of the rotating shaft 122.

  As can be seen from FIG. 6, when the X-ray CT apparatus is used for dentistry, it is necessary to position a tooth that is an object to be photographed in the approximate center between the X-ray generation apparatus 104 and the X-ray imaging apparatus 105, and The X-ray generation device 104 and the X-ray imaging device 105 basically need to be rotated around the position of the teeth, so the chair seat surface portion support column 123 that supports the position of the center of gravity of the subject. The center position is different from the center position of the rotating shaft 122. For this reason, the rotating shaft 122 is formed with a hollow portion having a certain thickness so that the chair seat surface supporting column 123 passing through the rotating shaft 122 does not get in the way even when the rotating shaft 122 is rotated. ing.

  The rotation drive mechanism 120 for the rotation shaft 122 is a column coupling unit that couples the X-ray generation device column 106 and the X-ray imaging device column 107 that support the X-ray generation device 104 and the X-ray imaging device 105, respectively. It is incorporated in 108. In addition, a lift drive mechanism 121 that lifts and lowers the chair seat surface portion 113 is incorporated in the chair base portion 110. These drive mechanisms 120 and 121 can be configured by a known mechanical mechanism including a drive source such as a motor, and are not the gist of the present invention, and thus detailed description thereof is omitted here. To do.

  FIG. 6 shows the dimensions of each part of the X-ray CT apparatus according to the embodiment of the present invention. As shown in FIG. 6, the center height of the X-ray generator 104 and the X-ray imaging device 105 is 1540 mm from the floor, the height to the top of the X-ray generator 104 is 1840 mm from the floor, and the mat 102. The height to the upper surface is 50 mm from the floor surface. The distance between the back surfaces of the X-ray generator 104 and the X-ray imaging device 105 is 1500 mm, and this center is the position of the imaging region. The distance from the front surface of the X-ray generation device 104 to the position of the imaging region is 320 mm, and the distance from the front surface of the X-ray imaging device 105 to the position of the imaging region is 300 mm.

  FIG. 7 is a trihedral view showing the shape of the power supply box. As shown in FIG. 7, the power supply box 118 is formed in a triangular prism shape having a substantially triangular cross-sectional shape obtained by scraping off an acute angle portion of a right-angled isosceles triangle. The dimensions of the cross section are the length of the isosceles portion of 500 mm and the length of the side formed by cutting off the acute angle portion. And the height is 1400 mm. The power box 118 having such a shape is disposed outside the mat 102 with the long side portion of the power box 118 facing the arc-shaped edge of the mat 102. As described above, since the diameter of the mat 102 is 1640 mm, the X-ray CT apparatus including the power supply box 118 can be 1800 mm × 1800 mm in size by such an arrangement.

  According to the above-described embodiment of the present invention, the rotation axis for rotating the X-ray generation device 104 and the X-ray imaging device 105 with the subject's head interposed therebetween is provided on the floor side of the device. As in the case of the prior art, it is possible to eliminate the need to install a structure unit such as a means for holding the X-ray generation apparatus and the X-ray imaging apparatus and a means for rotationally driving them above the subject's head.

  Thus, according to the above-described embodiment of the present invention, a sufficient space can be secured above the subject's head, and the space between the X-ray generator 104 and the X-ray imaging device 105 is wide. Since space can be secured, it is possible to prevent the subject from being given a feeling of pressure or blockage by the device, avoiding danger such as the subject colliding with the structure of the device, Safety can be improved, and further, the apparatus height and installation space can be reduced.

It is the perspective view seen from the front side of the X-ray CT apparatus by one Embodiment of the present invention. It is the perspective view seen from the rear surface side of the X-ray CT apparatus by one Embodiment of this invention. It is a front view of the X-ray CT apparatus by one Embodiment of this invention. It is a side view in the state where the subject got on X-ray CT apparatus by one embodiment of the present invention. It is a top view in the state where the subject got on X-ray CT apparatus by one embodiment of the present invention. It is a figure which controls about the rotation drive mechanism of an X-ray generator and an X-ray imaging device, and the raising / lowering drive mechanism of a chair seat surface part. It is a 3rd view which shows the shape of a power supply box. It is a figure which shows the basic structural example of the sitting type X-ray CT apparatus by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Floor surface 102 Mat | matte 103 Step 104 X-ray generator 105 X-ray imaging device 106 X-ray generator support column 107 X-ray imaging device support column 108 Support link 109 Footrest 110 Chair base 111 Chair back 112 Armrest 113 Chair Seat Surface 114 Foot Guard 115 Head Fixing Device 116 Jaw Fixing Device 117 Head and Jaw Fixing Support Column 118 Power Supply Box 119 Handle 120 Rotation Drive Mechanism 121 Lifting Drive Mechanism 122 Rotating Shaft 123 Chair Seat Surface Support Column 124 Base Stand

Claims (7)

In an X-ray CT apparatus for rotating and irradiating a subject with an X-ray beam and capturing a projected image thereof,
A subject chair supported by a base installed on the floor;
A strut connecting part disposed under the subject chair and rotatably attached to the base via a rotation drive mechanism part,
An X-ray generation means column and an X-ray detection unit column coupled to the column coupling unit so as to sandwich the subject chair ;
An X-ray generation means for generating an X-ray beam attached to each of the X-ray generation means support and the X-ray detection means support, and an X-ray detection means for detecting an X-ray image transmitted through a subject,
The X-ray CT apparatus characterized in that the rotation drive mechanism unit rotates the X-ray generation unit and the X-ray detection unit across the fixed subject chair by rotating the support column coupling unit. .
The X-ray CT apparatus according to claim 1,
The X-ray CT apparatus is characterized in that the column connecting portion includes a step at a front and rear position in a state where the column for the X-ray generation unit and the column for the X-ray detection unit are positioned on the left and right. . The X-ray CT apparatus according to claim 1 or 2,
The column connecting portion is supported by the base by a hollow pipe-shaped rotating shaft portion,
The subject chair is attached via a chair supporting column attached to a base through the inside of the rotating shaft portion,
The X-ray CT apparatus, wherein the rotation drive mechanism is provided inside the support column connecting portion. The X-ray CT apparatus according to claim 3.
The subject chair includes a chair seat surface portion including an armrest on which the subject sits, a chair pedestal portion, and a chair backrest connected to the rear surface of the chair pedestal portion,
The X-ray CT apparatus characterized in that the chair seat surface part can be lifted and lowered via a lift drive mechanism provided inside the chair base part. The X-ray CT apparatus according to claim 4.
The front side of the chair pedestal has a member that is one step lower and protrudes in a circular shape forward,
An X-ray CT apparatus, wherein the member is provided with an arcuate plate-like foot guard so as to be movable along a circular circumferential portion of the member. The X-ray CT apparatus according to claim 4 or 5,
The chair back has an outer periphery on the back side formed in an arc shape along a rotation trajectory between the X-ray generation means support column and the X-ray detection means support column, and the X-ray generation unit and An X-ray CT apparatus comprising a control device, an image processing device, and a communication device for the X-ray detection means. The X-ray CT apparatus according to claim 4, 5 or 6,
The X-ray CT apparatus characterized in that the pedestal for chair is provided with a head fixing device and a chin fixing device attached via a head and a column for a chin fixing device.

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