JP2017023326A - Medical X-ray imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of reducing an influence of scattered rays during cephalometric radiography while achieving space saving of a medical X-ray imaging apparatus.SOLUTION: A medical X-ray imaging apparatus 1 is configured to execute panoramic X-ray imaging and CT imaging when a first detector 30 receives an X-ray beam B1, and execute cephalometric radiography when a second detector 56 receives the X-ray beam B1. The medical X-ray imaging apparatus 1 comprises: a turning arm drive control section 71 for controlling a turning drive part 167 so that a first detector storage part 3 is positioned between a generator 20 and the second detector 56 during the cephalometric radiography; and a retreat movement mechanism 32 for moving the first detector 30 between a light reception position DTP and a retreat position EVP. The first detector storage part 3 comprises: a head imaging collimator 34 for restricting the spread of the X-ray beam B1 from the generator 20 toward the second detector 56; and transmission allowing parts RL1, RL2 each constituting an exterior portion of the first detector storage part 3 for transmitting the X-ray beam B1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a medical X-ray imaging apparatus.

  2. Description of the Related Art There has been known a technique for performing head X-ray standard imaging for obtaining a head X-ray standard photograph by combining a Cephalo unit with a medical X-ray imaging apparatus such as panoramic X-ray imaging.

  For example, Patent Document 1 discloses a technique for obtaining a radiographic image of a skull by attaching a cephalostat to a panoramic X-ray imaging apparatus. Specifically, when a radiographic image is obtained, a film cassette used in panoramic exposure is retracted, and an X-ray beam regulated by a blind of an X-ray generator is irradiated on the patient's head. A soft tissue filter is attached to the end of a movable film cassette used for panoramic exposure and placed on a part of the optical path of the X-ray beam in order to obtain a radiographic image of the skull that can sufficiently identify soft tissue. It is described to do.

  Further, in Patent Document 2, an X-ray beam from an X-ray generator passes through a case in which a detector used in PAN / 3D imaging is accommodated during cephalometric imaging, and the patient's head. Has been disclosed (FIG. 4c).

JP-A-7-8484 US Pat. No. 8,152,373

  In the apparatus disclosed in Patent Document 1, the spread of the X-ray beam is regulated by the blind of the X-ray generator. Then, in radiographic photography, the distance between the X-ray generator and the film is longer than in panoramic X-ray photography, so that the X-ray scattered rays generated in the blind are greatly displaced from the incident position on the film. In contrast, the contrast and sharpness may decrease.

  Moreover, in the apparatus disclosed in Patent Document 2, the spread of the X-ray beam is regulated by a regulating member arranged in the cephalo unit. For this reason, although the influence of a scattered ray becomes small compared with the case where the expansion of an X-ray beam is controlled by an X-ray generator, a configuration for arranging the control member on the X-ray beam is required.

  Therefore, an object of the present invention is to provide a technique capable of reducing the influence of scattered radiation at the time of head X-ray standard imaging while saving space in a medical X-ray imaging apparatus.

  In order to solve the above problems, a first aspect includes a generator that generates an X-ray beam, and a detector storage unit that stores therein a first detector that detects the X-ray beam from the generator. X-ray imaging of a head, a support part for supporting the generator and the detector accommodating part so that the generator and the first detector can face each other, a turning drive part for turning the support part, and the head A second detector that detects the X-ray beam that has passed through the head during head X-ray standard imaging, and a head fixing unit that fixes the head during the head X-ray standard imaging A first imaging in which the first detector receives the X-ray beam and performs imaging, and a second imaging in which the second detector receives the X-ray beam and performs the cephalometric X-ray imaging. A medical X-ray imaging apparatus configured to be executable, wherein the detector is accommodated during the second imaging. A swivel drive control unit that controls the swivel drive unit so as to be positioned between the generator and the second detector, and the first detector, and the X-ray beam during the first imaging. A detector moving portion that further moves between a light receiving position to be received and a retracted position that is retracted from an optical path of the X-ray beam directed to the second detector during the second imaging; Comprises an X-ray restricting part for head imaging that restricts the spread of the X-ray beam from the generator toward the second detector, and an exterior part of the detector accommodating part, from the generator A transmission allowing portion that transmits the X-ray beam directed toward the second detector.

  Moreover, a 2nd aspect is a medical X-ray imaging apparatus which concerns on a 1st aspect, Comprising: The said head imaging | photography X-ray control part can vary the breadth of the said X-ray beam toward the said 2nd detector. To regulate.

  Moreover, a 3rd aspect is a medical X-ray imaging apparatus which concerns on a 1st or 2nd aspect, Comprising: The said head imaging | photography X-ray control part to the area | region except the maxillofacial area of the said head. The X-ray beam is suppressed from being irradiated.

  Moreover, a 4th aspect is a medical X-ray imaging apparatus which concerns on any 1 aspect among the 1st-3rd aspects, Comprising: The said X-ray control part for head imaging | photography WHEREIN: The said X-ray is unidirectional. A slit-like collimator that forms an X-ray slit beam by a slit extending to the slit, and a slit moving mechanism that scans a region to be imaged with the slit beam by moving the slit, and the second detector Comprises an elongated detection surface for detecting the slit beam, and a detection surface moving mechanism for moving the elongated detection surface in synchronization with the movement of the slit beam.

  Moreover, a 5th aspect is a medical X-ray imaging apparatus which concerns on any one aspect among the 1st-3rd aspects, Comprising: The said head imaging | photography X-ray control part controls the said X-ray. A collimator for injecting radiation that forms a wide-area X-ray beam that simultaneously irradiates the X-rays to the entire imaging target region in the head, and the second detector transmits the imaging target region. A wide-area detection surface for detecting the wide-area X-ray beam at a time.

  A sixth aspect is the medical X-ray imaging apparatus according to the fifth aspect, wherein the injection irradiation collimator is configured to capture the front of the head and the head in the second imaging. The amount of restriction for restricting the spread of the X-ray beam is changed in the case of photographing the side surface of the part.

  A seventh aspect is a medical X-ray imaging apparatus according to any one of the first to sixth aspects, wherein the first imaging mode for executing the first imaging and the second imaging are performed. A shooting mode selection receiving unit that receives a selection of a specific shooting mode from a plurality of shooting modes including a second shooting mode to be executed, and the shooting mode selection receiving unit receives a selection of the second shooting mode; The retract movement mechanism moves the first detector to the retract position.

  Further, an eighth aspect is a medical X-ray imaging apparatus according to the seventh aspect, wherein the generator is housed inside and the generator housing part supported by the support part, and the generation And an X-ray restricting unit that restricts an irradiation range by shielding the X-ray emitted from the generator by a shielding plate and received by the imaging mode selection accepting unit. The X-ray beam irradiation range is changed by the X-ray restricting unit moving the shielding plate according to the imaging mode.

  Further, a ninth aspect is a medical X-ray imaging apparatus according to any one of the first to eighth aspects, wherein the first imaging is at least one of panoramic X-ray imaging and CT imaging. On the other hand.

  A tenth aspect is a medical X-ray imaging apparatus according to the eighth aspect, and the first imaging includes panoramic X-ray imaging and CT imaging, and the X-ray restricting unit includes the panorama. In X-ray imaging, the X-ray is regulated so that the detection surface of the first detector is irradiated upward, and in CT imaging, the X-ray is incident at a right angle on the detector of the first detector. The X-ray is regulated.

  An eleventh aspect is a medical X-ray imaging apparatus according to any one of the first to tenth aspects, wherein the turning drive unit includes the generator and the detector. The swivel mechanism is swung around a swivel axis set at a position between the housing unit and the retracting movement mechanism moves the first detector along the axial direction of the swivel axis.

  A twelfth aspect is a medical X-ray imaging apparatus according to any one of the first to eleventh aspects, and is housed in the detector housing portion, and the second detector includes It further includes a dose reduction filter for reducing a part of the X-ray beam that travels.

  A thirteenth aspect is a medical X-ray imaging apparatus according to the twelfth aspect, which is accommodated in the detector accommodating portion and moves the dose reduction filter in accordance with the position of the soft tissue in the head. And a dose reduction filter moving mechanism.

  A fourteenth aspect is a medical X-ray imaging apparatus according to any one of the first to thirteenth aspects, provided in the detector accommodating portion, and provided in the second detector. A soft X-ray removal filter that removes soft X-rays of the X-ray beam that travels is further provided.

  A fifteenth aspect is a medical X-ray imaging apparatus according to the fourteenth aspect, wherein the soft X-ray removal filter is an X-ray transmissive metal plate that constitutes the permeation permission portion.

  According to the medical X-ray imaging apparatus according to the first aspect, at the time of head X-ray standard imaging, the X-ray is detected by the head imaging X-ray restricting unit of the detector housing unit arranged at a point in the middle of the X-ray path. Since the spread of the beam is regulated, the influence of the scattered radiation in the X-ray projection image can be reduced compared with the case where the spread is regulated in the vicinity of the generator, and the spread of the X-ray beam can be regulated with higher accuracy. Furthermore, space saving can be achieved by accommodating and integrating the X-ray restricting portion for head imaging in the detector accommodating portion accommodating the first detector used for the first imaging.

  In addition, according to the medical X-ray imaging apparatus according to the second aspect, the restriction amount of the X-ray spread can be changed in accordance with the imaging range and imaging method.

  In addition, according to the medical X-ray imaging apparatus according to the third aspect, X-ray irradiation can be performed only in a region including the maxillofacial area, so that the X-ray exposure dose of the subject can be reduced.

  Moreover, according to the medical X-ray imaging apparatus which concerns on a 4th aspect, since the area of a 2nd detector can be made comparatively small, 2nd imaging | photography can be performed at low cost.

  Further, according to the medical X-ray imaging apparatus according to the fifth aspect, cephalometric X-ray imaging can be performed in a short time, and image processing is not particularly required.

  Further, according to the medical X-ray imaging apparatus according to the sixth aspect, the amount of restriction on the spread of X-rays is suitably controlled in accordance with each of the case of photographing the front of the head and the case of photographing the side of the head. it can.

  Further, according to the medical X-ray imaging apparatus according to the seventh aspect, the medical X-ray imaging apparatus can be operated so as to perform imaging corresponding to the imaging mode when the operator selects the imaging mode. . For this reason, operation of a medical X-ray imaging apparatus can be simplified.

  Moreover, according to the medical X-ray imaging apparatus which concerns on an 8th aspect, an X-ray beam can be shape | molded by arbitrary shapes by moving a shielding board.

  Moreover, according to the medical X-ray imaging apparatus which concerns on a 9th aspect, CT imaging | photography or panoramic X-ray imaging and head X-ray standard imaging | photography can be performed with the same apparatus.

  Further, according to the medical X-ray imaging apparatus according to the tenth aspect, the incident angle of the X-ray beam with respect to the first detector can be adjusted to be an angle suitable for each of panoramic imaging and CT imaging.

  In addition, according to the medical X-ray imaging apparatus according to the fourteenth aspect, the X-ray exposure dose of the subject can be reduced by removing the soft X-rays from the X-ray beam by the soft X-ray removal filter.

  Further, according to the medical X-ray imaging apparatus according to the fifteenth aspect, the soft X-ray removal filter is an X-ray transmissive metal plate that constitutes the exterior part of the detector accommodating part, so that the inside of the detector accommodating part. A space for installing the soft X-ray removal filter becomes unnecessary, and the thickness of the detector housing portion can be reduced. Moreover, it can suppress that the external appearance property and protection property of a detector accommodating part are impaired by comprising the exterior part of a detector accommodating part with an X-ray transparent metal plate.

1 is a block diagram illustrating a configuration of a medical X-ray imaging apparatus according to a first embodiment. It is a perspective view which shows the generator side collimator which concerns on 1st Embodiment. 1 is a front view showing a medical X-ray imaging apparatus according to a first embodiment. 1 is a plan view showing a medical X-ray imaging apparatus according to a first embodiment. It is a front view which shows the 1st detector accommodating part seen from the AA cross-section position shown in FIG. It is a front view which shows the 1st detector seen from the BB cross-section position shown in FIG. It is a front view which shows the collimator for head imaging | photography seen from the CC cross-section position shown in FIG. It is a front view which shows the 2nd detector seen from the DD cross-section position shown in FIG. It is a figure which shows the dose reduction filter unit which concerns on 1st Embodiment. It is a front view which shows the filter part for the front seen from the Y direction. It is a side view which shows the modification of the filter part for side surfaces. It is a perspective view of the highly sensitive site | part irradiation control unit for protecting a highly sensitive site | part from X-ray irradiation. It is a perspective view of the highly sensitive site | part irradiation control unit for protecting a highly sensitive site | part from X-ray irradiation. It is a figure which shows the position of the shielding part with respect to the filter part for the front at the time of frontal cephalo imaging shown in FIG. It is a figure which shows the position of the shielding part with respect to the filter part for side surfaces at the time of side surface cephalo imaging shown in FIG. It is a schematic perspective view which shows the positional relationship of the dose reduction filter unit which concerns on 1st Embodiment, a generator, and a 2nd detector. It is a front view which shows the medical X-ray imaging apparatus at the time of panoramic X-ray imaging. It is a front view which shows the medical X-ray imaging apparatus at the time of CT imaging. It is a flowchart which shows operation | movement of the medical X-ray imaging apparatus which concerns on 1st Embodiment. It is a conceptual diagram for demonstrating the imaging area | region in head X-ray standard imaging | photography. It is a front view which shows the medical X-ray imaging apparatus which concerns on 2nd Embodiment. It is a top view which shows the medical X-ray imaging apparatus which concerns on 2nd Embodiment. It is a front view which shows the collimator for head imaging | photography seen from the EE cross-section position shown in FIG. It is a schematic plan view which shows a pair of movable shielding board which concerns on 2nd Embodiment. It is a front view which shows the 2nd detector seen from the FF cross-section position shown in FIG. It is a flowchart which shows operation | movement of the medical X-ray imaging apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the component described in this embodiment is an illustration to the last, and is not a thing of the meaning which limits the scope of the present invention only to them. In the drawings, the size and number of each part may be exaggerated or simplified as necessary for easy understanding.

<1. First Embodiment>
FIG. 1 is a block diagram showing a configuration of a medical X-ray imaging apparatus 1 according to the first embodiment. FIG. 2 is a perspective view showing the generator-side collimator 22 according to the first embodiment. FIG. 3 is a front view showing the medical X-ray imaging apparatus 1 according to the first embodiment. FIG. 4 is a plan view showing the medical X-ray imaging apparatus 1 according to the first embodiment. FIG. 5 is a front view showing the first detector housing 3 as seen from the AA cross-sectional position shown in FIG. FIG. 6 is a front view showing the first detector 30 viewed from the BB cross-sectional position shown in FIG. FIG. 7 is a front view showing the head photographing collimator 34 as seen from the CC cross-sectional position shown in FIG. FIG. 8 is a front view showing the second detector 56 as seen from the DD cross-section position shown in FIG.

  The medical X-ray imaging apparatus 1 is configured to perform various X-ray imaging including panoramic X-ray imaging, CT imaging, and cephalometric X-ray standard imaging (cephalometric imaging).

  Specifically, the medical X-ray imaging apparatus 1 includes a main body unit 10, a main body control unit 70, an operation unit 80, and an image processing unit 90. The operation unit 80 is an input unit that is operated to receive input of various settings related to X-ray imaging and to give an operation command to the main body unit 10 of the medical X-ray imaging apparatus 1. The main body unit 10 performs various X-ray imaging based on information input via the operation unit 80, and acquires projection data representing an X-ray projection image of the subject (patient). The main body control unit 70 controls the operation of each element of the main body unit 10 according to a program (not shown) in order to cause the main body unit 10 to perform various X-ray imaging. The image processing unit 90 processes the projection data acquired by the main body unit 10 to generate various X-ray images. The main body control unit 70, the main body unit 10, the operation unit 80, and the image processing unit 90 are connected to each other so as to be capable of wired communication or wireless communication.

<Main body>
Preferably, the main body portion 10 is accommodated in a hollow vertically long rectangular parallelepiped X-ray prevention chamber (not shown) at the site of X-ray imaging. The main body 10 includes a generator 20 (X-ray generator) that generates X-rays and a first detector 30 that detects X-rays emitted from the generator 20. The generator 20 is housed inside the generator housing 2, and the first detector 30 is housed inside the first detector housing 3. The generator accommodating portion 2 and the first detector accommodating portion 3 are respectively attached to both ends of a swivel arm 4 (support portion) that is a long member extending in one direction. The swivel arm 4 constitutes a support portion that supports the generator 20 and the first detector 30 so that they can face each other.

  The swivel arm 4 is supported by the upper frame 14 via a swivel shaft 12 connected to an intermediate position between the generator 20 and the first detector housing 3. The upper frame 14 incorporates a turning arm drive unit 16 (see FIG. 1). The swivel arm drive unit 16 turns the swivel arm 4 around the swivel axis 12 as well as the X-axis drive motor 161, the Y-axis drive motor 163, and the Z-axis drive motor 165 that move the swivel arm 4 in the XYZ directions. A driving unit 167 is provided.

  The turning drive unit 167 includes a motor for turning the turning arm 4 around the turning shaft 12, a belt for transmitting a driving force of the motor, and the like. In panoramic X-ray imaging or CT imaging, the swivel arm 4 rotates around the swivel axis 12 with a subject (here, the head HP1) disposed between the generator 20 and the first detector 30 facing each other. To do. Then, panoramic X-ray imaging or CT imaging is performed by the first detector 30 detecting the X-ray beam while the generator 20 is turning around the subject while emitting the X-ray beam. Panoramic X-ray imaging and CT imaging in which the first detector 30 receives and captures X-rays from the generator 20 correspond to first imaging.

  The X-axis drive motor 161 and the Y-axis drive motor 163 move the swing arm 4 in a direction perpendicular to the swing axis 12 (here, the horizontal direction). The Z-axis drive motor 165 moves in a direction parallel to the turning shaft 12 (here, a vertical direction). The X-axis drive motor 161 and the Y-axis drive motor 163 constitute an XY table (not shown) fixed to the upper frame 14 that supports the swing arm 4 via, for example, the swing shaft 12. The XY table includes, for example, a table member that moves in the X-axis direction that is one direction in the horizontal direction, and a table member that moves in the Y-axis direction that is the horizontal direction perpendicular to the X-axis direction. Then, the upper end portion of the turning shaft 12 is fixed to the XY table, and the lower end portion of the turning shaft 12 is fixed to the turning arm 4. By driving the X-axis drive motor 161 and the Y-axis drive motor 163 of the XY table, the swing arm 4 moves in a direction perpendicular to the swing axis 12 together with the swing axis 12. The XY table can also be provided on the revolving arm 4 side. In this case, only the turning arm 4 moves in a direction perpendicular to the turning shaft 12.

  The upper frame 14 is engaged with a support column 18 erected along the vertical direction. The Z-axis drive motor 165 moves the upper arm 14 up and down along the column 18 along the Z-axis direction that is the vertical direction, thereby moving the swing arm 4 up and down.

  In the following description, a direction in which the generator 20 and the first detector 30 face each other is referred to as a “y-axis direction”, and in particular, a direction from the generator 20 toward the first detector 30 is referred to as a + y direction. Further, the horizontal direction orthogonal to the y-axis direction is referred to as the “x-axis direction”, and particularly the left-hand direction when directed from the −y side to the + y side is the + x side. Further, a vertical direction orthogonal to the x-axis direction and the y-axis direction is defined as a z-axis direction, and particularly upward in the vertical direction is defined as a + z side. However, these are defined in order to explain the positional relationship and the like of each element of the medical X-ray imaging apparatus 1, and limit the positional relationship and the like of each element of the medical X-ray imaging apparatus according to the present invention. It is not intended.

<Generator housing>
A generator 20 and a generator-side collimator 22 are accommodated in the generator accommodating portion 2.

  The generator 20 includes an X-ray tube that generates X-rays. As shown in FIG. 2, the generator 20 is accommodated in a housing 21 (see FIG. 2). On the front side (that is, the + y side) of the housing 21 is provided an exit port 210 that allows passage of X-rays generated by the X-ray tube. A generator-side collimator 22 that functions as an X-ray restricting unit is disposed in front of the emission port 210 (front side in FIG. 2).

  The generator-side collimator 22 includes a pair of longitudinal shielding plates 221 and 221, a longitudinal movement mechanism 222, a pair of lateral shielding plates 223 and 223, and a lateral movement mechanism 224 that moves these in the lateral direction. I have. The vertical shielding plate 221 and the horizontal shielding plate 223 are examples of X-ray shielding members that control the shielding amount of X-rays emitted from the generator 20.

  The vertical direction shielding plates 221 and 221 are made of metal (lead or the like) horizontally long plates arranged on the upper and lower sides (+ z side and −z side) in the front view of the emission port 210, and the vertical direction (z Move in the axial direction) to shield X-rays. The horizontal direction shielding plate 223 is composed of a vertically long plate made of metal (such as lead) disposed on the left and right sides (−x side and + x side) in front view of the emission port 210, and is formed in the horizontal direction (x-axis direction). ) To shield X-rays. In the example shown in FIG. 2, the horizontal shielding plate 223 is disposed on the side closer to the housing 21 (−y side) than the vertical shielding plate 221, but the vertical shielding plate 221 is disposed on the horizontal shielding plate 223. It may be arranged closer to the housing 21.

  The vertical movement mechanism 222 moves the pair of vertical shielding plates 221 and 221 individually in the vertical direction. Specifically, the longitudinal movement mechanism 222 includes a pair of longitudinal screw shafts 222a and 222a extending in the longitudinal direction, and a pair of motors 222b and 222b that rotate the longitudinal screw shafts 222a and 222a forward and backward. Yes. Nut members 221a and 221a attached to the vertical shielding plates 221 and 221 are screwed into the vertical screw shafts 222a and 222a, respectively. When the vertical screw shafts 222a and 222a rotate forward or backward by driving the motors 222b and 222b, the nut members 221a and 221a move up and down along the vertical direction, respectively. Accordingly, the vertical shielding plates 221 and 221 move independently in the vertical direction.

  The vertical movement mechanism 222 controls the X-ray beam irradiation direction (the direction in which the center line of the expansion extends) by adjusting the spread (irradiation range) in the vertical direction of the X-ray beam, that is, the axial direction of the turning shaft 12. To do.

  Cylindrical slide members 221b and 221b are attached to the vertical shielding plates 221 and 221, respectively. The slide members 221b and 221b are formed with through holes penetrating along the vertical direction. A rod-shaped shaft 221c extending in the vertical direction is inserted through each through hole, and movement of the slide members 221b and 221b in the horizontal direction is suppressed. For this reason, the vertical shielding plates 221 and 221 can be moved in the vertical direction without being inclined.

  The lateral movement mechanism 224 moves the pair of lateral shielding plates 223 and 223 individually in the lateral direction. Specifically, the lateral movement mechanism 224 includes a pair of lateral screw shafts 224a and 224a extending in the lateral direction, and a pair of motors 224b and 224b that rotate the respective lateral screw shafts 224a and 224a forward and backward. Yes. Nut members 223a and 223a attached to the horizontal shielding plates 223 and 223 are screwed into the horizontal screw shafts 224a and 224a, respectively. When the horizontal screw shafts 224a and 224a rotate forward or backward by driving the motors 224b and 224b, the nut members 223a and 223a move left and right along the horizontal direction. Thereby, each horizontal direction shielding board 223,223 moves to a horizontal direction independently.

  The lateral movement mechanism 224 adjusts the lateral direction of the X-ray beam, that is, the spread (irradiation range) in the X-ray axis direction perpendicular to the axial direction of the swivel axis 12, thereby irradiating the X-ray beam. Control direction).

  Cylindrical slide members 223b and 223b are attached to the horizontal shielding plates 223 and 223, respectively. The slide members 223b and 223b are formed with through holes penetrating along the lateral direction. A bar-shaped shaft 223c extending in the horizontal direction is inserted through each through hole, and movement of the slide members 223b and 223b in the vertical direction is suppressed. For this reason, the horizontal direction shielding plates 223 and 223 can move in the horizontal direction without being inclined.

  Thus, in the present embodiment, the generator-side collimator 22 is disposed in front of the emission port 210 from which the X-rays from the generator 20 are emitted, so that the irradiation range of the X-rays generated by the generator 20 is reached. Is restricted by the shielding, and an X-ray beam spreading in a truncated pyramid shape toward the first detector 30 is formed.

  Specifically, the distance between the opposing edges 221d and 221d in the vertical shielding plates 221 and 221 is adjusted by the vertical movement mechanisms 222 and 222, and the distance between the opposing edges 223d and 223d in the horizontal shielding plates 223 and 223 is adjusted. The interval is adjusted by the lateral movement mechanisms 224 and 224. Then, the opposed edge portions 221d and 221d and the opposed edge portions 223d and 223d form a rectangular opening 226 in front view for forming an X-ray beam having a desired shape, that is, an X-ray opening in front of the generator 20.

  For example, the opening 226 becomes a relatively large square-shaped large-field opening when viewed from the front by adjusting the distance between the facing edges 221d and 221d and the distance between the facing edges 223d and 223d wide. . The X-ray that has passed through the large irradiation field opening has a square cross section and becomes an X-ray beam (X-ray cone beam) that spreads toward the first detector 30 in a square pyramid shape.

  Further, the opening between the opposing edges 221d and 221d is adjusted to be wide, and the distance between the opposing edges 223d and 223d is adjusted to be narrow, so that the opening 226 is a rectangular panoramic X-ray imaging opening that is vertically long in front view. It is said. The X-ray that has passed through the panoramic X-ray imaging opening has an elongated rectangular cross section, and becomes an X-ray slit beam that spreads in a vertically long truncated pyramid toward the first detector 30.

  The generator-side collimator 22 is not limited to the one that forms the opening 226 with four shielding plates. For example, two L-shaped shielding plates may be combined and the opening 226 may be formed. In this case, the size of the opening 226 can be changed by moving the two L-shaped shielding plates in the x-axis direction and the z-axis direction.

  As shown in FIG. 6, the detection surface of the first detector 30 is an area for receiving a panoramic X-ray imaging X-ray beam (slit X-ray beam) (panoramic light receiving area PA), and for CT imaging of a small irradiation field. Wide enough to accommodate both the X-ray beam receiving region (small irradiation field CT light receiving region NCA) and the large irradiation field CT image receiving X-ray beam (large irradiation field CT light receiving region WCA). have. In this way, the formation of various X-ray beams for panoramic X-ray imaging and CT imaging is basically performed by the generator-side collimator 22.

<First detector housing portion>
A first detector 30, a retracting movement mechanism 32, a head photographing collimator 34, and a dose reduction filter unit 36 are provided inside the first detector housing 3.

  The first detector 30 is composed of an image sensor composed of a plurality of X-ray detection elements arranged so as to spread in a two-dimensional plane (here, xz plane). The X-ray detection element converts a signal corresponding to the intensity of the X-ray into an electric signal and outputs it to the outside. The image sensor converts incident X-rays into frame image data (image information) at a required frame rate. The said frame image data is data showing the image which has a pixel value according to the intensity | strength of incident X-ray for every pixel.

  As the first detector 30, a MOS sensor or a CMOS sensor can be suitably used, but any electrical imaging sensor may be used as long as a frame image can be obtained. Specifically, various devices such as a flat panel detector (FPD) such as a CCD sensor and other solid-state imaging devices can be used.

<Backward movement mechanism>
As shown in FIG. 6, the retracting movement mechanism 32 housed in the first detector housing unit 3 includes a motor 321, a screw shaft 323, and a shaft 325. The screw shaft 323 is rotationally driven by a motor 321. The shaft 325 is a rod-like member extending in parallel to the vertical direction. Two nut members 301 and 301 that are screwed onto the screw shaft 323 are attached to one side of the both sides of the first detector 30. Two slide members 303 and 303 are attached to the other side of the both sides of the first detector 30. The slide members 303 and 303 are provided with holes penetrating in the vertical direction, and a shaft 325 is inserted through these holes.

  The retracting movement mechanism 32 rotates the screw shaft 323 to move the first detector 30 together with the nut members 301 and 301 in the vertical direction (that is, the direction parallel to the turning shaft 12). At that time, the movement direction of the slide members 303 and 303 is restricted by the shaft 325, so that the first detector 30 linearly moves along the vertical direction. The retreat movement mechanism 32 moves the first detector 30 between the light receiving position DTP and the retreat position EVP (see FIG. 6 and the like). Here, the light receiving position DTP is a position where the first detector 30 receives an X-ray beam in panoramic X-ray imaging or CT imaging (first imaging). The retreat position EVP is a position for retreating from the optical path of the X-ray beam directed to the second detector 56 at the time of cephalometric X-ray standard imaging (second imaging).

<Slit collimator>
When the first detector 30 is at the retracted position EVP, the X-ray beam emitted from the generator 20 passes through the first detector housing 3 and is regulated by the head imaging collimator 34. As shown in FIG. 7, the head photographing collimator 34 is formed with an elongated opening 34 </ b> S (slit) extending in one direction. The X-ray beam that has passed through the opening 34S is incident on the second detector 56 inside the second detector accommodating portion 54 of the cephalostat CSA as a slit X-ray beam NB1 for head imaging. The head photographing collimator 34 is a configuration example of a slit collimator.

<Slit moving mechanism>
As shown in FIGS. 1 and 7, the first detector housing 3 houses a slit moving mechanism 340 that moves the head imaging collimator 34 in the x-axis direction. As shown in FIG. 7, the slit moving mechanism 340 includes a belt 341, a motor 343, a shaft 345, and slide members 347 and 347.

  The back side of the head photographing collimator 34 is fixed to the belt 341. The belt 341 is wound around a pair of roller members 341a and 341a disposed at positions separated in the x-axis direction. One roller member 341a is configured to rotate by driving of a motor 343, and the other roller member 341a is configured to freely rotate. Two slide members 347 and 347 are attached to the head photographing collimator 34 at an interval in the x-axis direction. Each of the slide members 347 and 347 is formed with a hole penetrating in the x-axis direction, and a rod-shaped shaft 345 extending in the x-axis direction is inserted through these holes.

  When the belt 341 is rotated by driving the motor 343, the head photographing collimator 34 moves to the left and right along the x-axis direction. At this time, the slide members 347 and 347 are in sliding contact with the shaft 345, so that the head photographing collimator 34 is linearly moved. As a result, the slit-shaped opening 34S of the head photographing collimator 34 moves in the x-axis direction.

<Cefaro unit>
The main body 10 includes a cephalo unit 5 for performing cephalometric radiography. The cephalometric unit 5 includes an arm 50 extending in the horizontal direction from the support column 18, a head fixing portion 52 and a second detector housing portion 54 attached to the tip of the arm 50.

<Head fixing part>
The head fixing unit 52 is configured to fix the head HP1 that is an object to be imaged in head X-ray standard imaging. Specifically, the head fixing part 52 has a pair of ear rods 521 and 521 inserted into the holes of both ears of the head HP1 and a nadion contact part 523 applied to a boundary point (nadion) between the frontal bone and the nasal bone. Is provided. The pair of ear rods 521 and 521 and the nadion contact portion 523 are held so as to be movable in the horizontal direction.

  For example, in the case of side cephalometric imaging in which the head HP1 is imaged from the side, as shown in FIG. 1, the ear rods 521 and 521 are inserted into both ears of the head HP1, thereby causing the head HP1 to move in the y-axis direction. Is positioned. Also, the head portion HP1 is positioned in the x-axis direction by causing the nadion contact portion 523 to contact the nadion of the head HP1.

  The head fixing unit 52 includes a measurement unit 525. The measurement unit 525 measures the position of each measurement point (here, the ear canal and nadion) of the head HP1 by detecting the position of the ear rods 521 and 521 and the position of the nadion contact part 523. The position information of each measurement point of the head HP1 obtained in this way is used when estimating the positions of the soft tissue and the hard tissue in the head HP1, as will be described later.

  In addition, although illustration is abbreviate | omitted, the ear rods 521 and 521 and the nadion contact part 523 are comprised so that it can rotate at least 90 degrees around a z-axis as a whole. Thereby, the head fixing | fixed part 52 can be fixed in the state in which the head HP1 faced the generator 20. FIG. Therefore, the medical X-ray imaging apparatus 1 is configured to execute not only the side surface side of the head HP1 but also head X-ray standard imaging (frontal cephalo imaging) for the front side of the head HP1.

<Detector moving mechanism>
As shown in FIG. 1 or FIG. 8, the second detector 56 is accommodated in the second detector accommodating portion 54. Similar to the first detector 30, the second detector 56 includes a plurality of X-ray detection elements arranged in a plane. However, the detection surface 561 of the second detector 56 is an elongated detection surface formed in an elongated shape.

  The second detector housing portion 54 is provided with a detector moving mechanism 58. The detector moving mechanism 58 moves the second detector 56 having the elongated detection surface 561 in the x-axis direction. Specifically, the detector moving mechanism 58 includes a belt 581, a motor 583, a shaft 585, and slide members 587 and 587.

  The belt 581 is fixed to the back side of the second detector 56. The belt 581 is wound around a pair of roller members 581a and 581a arranged at positions separated in the x-axis direction. One roller member 581a is configured to rotate by driving of a motor 583, and the other roller member 581a is configured to freely rotate. Two slide members 587 and 587 are attached to the upper portion of the second detector 56 with an interval in the x-axis direction. Each of the slide members 587 and 587 is formed with a hole penetrating in the x-axis direction, and a rod-shaped shaft 585 extending in the x-axis direction is inserted through these holes.

  When the belt 581 is rotated by driving the motor 583, the second detector 56 moves to the left and right along the x-axis direction. At this time, the slide members 587 and 587 are moved in sliding contact with the shaft 585, so that the second detector 56 moves linearly in the x-axis direction. As a result, the detection surface 561 moves in the x-axis direction. Thus, the detector moving mechanism 58 is an example of a detection surface moving mechanism.

<Permitted portion>
As shown in FIG. 3, in the second detector accommodating portion 54, at least a portion through which X-rays pass among the wall portions arranged between the generator 20 and the second detector 56 is X-ray transmissive. In order to prevent this, the transmission allowing portion RL3 made of a material that allows X-ray transmission is used.

<Head X-ray standard radiography>
Next, head X-ray standard imaging in the medical X-ray imaging apparatus 1 will be described with reference to FIG. Here, when the shielding plate in the head photographing collimator 34 moves in the x-axis direction, the opening moves in the x-axis direction. As a result, the slit X-ray beam NB1 moves in the x-axis direction, thereby scanning the imaging target region of the head HP1 with the slit X-ray beam NB1 in the x-axis direction. In the example shown in FIG. 4, the side surface of the subject's head HP1 is photographed. Here, the head HP1 is scanned with the slit X-ray beam NB1 from the occipital side to the frontal side. In the following description, the head X-ray standard imaging method of scanning a subject with an X-ray beam of a slit is referred to as a scanning method. In the case of scanning head X-ray standard imaging, as described later, the detection surface of the second detector is formed in an elongated shape in accordance with the slit X-ray beam NB1, and this is moved. The cost of the vessel can be reduced. Therefore, cephalometric radiography can be performed at low cost.

  The X-ray beam that passes through the opening 34S of the head imaging collimator 34 is an X-ray beam whose cross section is shaped vertically by the generator-side collimator 22. That is, the shielding plates (lateral shielding plates 223 and 223) of the generator-side collimator 22 move in synchronization with the movement of the head photographing collimator 34. As a result, the X-ray beam is irradiated in accordance with the position of the opening 34S of the head photographing collimator 34.

<Dose reduction filter unit>
FIG. 9 is a diagram showing the dose reduction filter unit 36 according to the first embodiment. FIG. 16 is a schematic perspective view showing the positional relationship among the dose reduction filter unit 36, the generator 20, and the second detector 56 according to the first embodiment.

  As shown in FIG. 16, the dose reduction filter unit 36 is housed in the first detector housing portion 3 and is irradiated to the second detector 56 during head X-ray standard imaging. It is arranged on the path of (slit X-ray beam NB1). As shown in FIG. 1, the dose reduction filter unit 36 is positioned closer to the second detector 56 than the head imaging collimator 34, but is not limited thereto. For example, the dose reduction filter unit 36 may be disposed closer to the generator 20 than the first detector 30, or is disposed between the first detector 30 and the head imaging collimator 34. Also good.

  The dose reduction filter unit 36 includes a dose reduction filter F1 and a dose reduction filter moving mechanism 360. The dose reduction filter F <b> 1 is made of copper or the like, and reduces the dose of the X-ray beam toward the second detector 56. Here, the dose reduction filter F1 includes a pair of filter portions F11 and F12 provided at a distance in the x-axis direction. The filter parts F11 and F12 exclude soft tissues (for example, skin or cartilage such as nose and ears, such as the bones including the skull and teeth) that are difficult to absorb X-rays in the head HP1 fixed by the head fixing part 52. It has a shape that reduces the dose of the X-ray beam incident on the tissue. Here, each filter part F11 and F12 has the shape where the inner side was dented in a concave shape. Further, the inner portions of the filter portions F11 and F12 are formed so that the thickness decreases toward the end portion.

  FIG. 16 is an example in which the head HP1 is imaged from the side, and the dose of the X-ray beam (slit X-ray beam NB1) irradiated to the soft tissue portion on the occipital side of the skull within the head HP1 is The X-ray beam is reduced by passing through the filter unit F11. In addition, the dose of the X-ray beam irradiated to the soft tissue such as the nose on the front side of the skull in the head HP1 is reduced by the filter unit F12. For this reason, as shown in FIG. 16, in the projection image PI1 of the side surface of the head HP1 acquired by the second detector 56, portions corresponding to the front side and the rear side of the skull pass through the filter units F11 and F12. The projected image portion PI11 by the X-ray beam. And the part corresponding to a skull, a jawbone, and a tooth becomes the projection image part PI12 by the X-ray beam which did not pass filter part F11, F12.

  As shown in FIG. 9, the dose reduction filter moving mechanism 360 includes a motor 361, a screw shaft 363, and a shaft 365. The motor 361, the screw shaft 363 and the shaft 365 are fixed to a part of the first detector housing 3. The filter portions F11 and F12 are attached to the frame members FP1 and FP2, and nut members 367 and 367 that are screwed into the screw shafts 363 are fixed to the upper end portions of the frame members FP1 and FP2, respectively. The portion of the screw shaft 363 to which the nut member 367 of the filter portion F11 is screwed is a normal screw 363a, whereas the portion of the screw shaft 363 to which the nut member 367 of the filter portion F12 is screwed is a reverse screw 363b. It has become. The screw groove of the normal screw 363a is inclined in the direction opposite to the screw groove of the reverse screw 363b. For this reason, when the motor 361 rotates the screw shaft 363 in one direction, one nut member 367 moves in the direction opposite to the other nut member 367. Therefore, it is possible to adjust the distance between the filter parts F11 and F12 by moving the filter parts F11 and F12 in the opposite directions along the x-axis direction.

  Slide members 369 having through holes penetrating in the x-axis direction are respectively attached to the lower ends of the frame members FP1 and FP2, and a rod-shaped shaft 365 extending in the x-axis direction is inserted into the through holes. . When the filter parts F11 and F12 move due to the rotation of the screw shaft 363, the slide members 369 slide and move the shaft 365 so that the filter parts F11 and F12 do not rotate around the screw axis in the x-axis direction. It is possible to move to.

  Here, the upper and lower portions extending in the x-axis direction on the upper and lower sides of the frame members FP1 and FP2 are fitted together. Specifically, the upper part and the lower part of the frame member FP1 have convex portions 371 and 371 whose central portions in the thickness direction protrude in the x-axis direction toward the frame member FP2. Further, in the upper part and the lower part of the frame member FP2, a concave part 373 in which the central part in the thickness direction is recessed in the x-axis direction is formed. The convex portion 371 can be inserted into the concave portion 373, and the convex portion 371 is fitted into the concave portion 373. Accordingly, the movement of the frame members FP1 and FP2 in the y-axis direction is suppressed, so that the filter portions F11 and F12 can be linearly moved in the x-axis direction.

  FIG. 10 is a front view showing the front filter portions F13 and F14 as viewed from the Y direction. The shapes of the filter portions F13 and F14 are adapted to the left and right soft tissue portions when the head is viewed from the front. Since the structure for driving the filter parts F13 and F14 is basically the same as that of the dose reduction filter unit 36, members other than the filter parts F13 and F14 are not shown. Such a front dose reduction filter unit including the filter parts F13 and F14 is provided at an upstream or downstream position in the vicinity of the side dose reduction filter unit 36 on the X-ray path.

  FIG. 11 is a side view showing a modified example of the side filter portions F11 and F12. A filter unit F15 is used instead of the filter units F11 and F11, and a filter unit F16 is used instead of the filter unit F12. The filter part F15 has substantially the same configuration as the filter part F11, but the filter part F16 has a shape protruding toward the neck so as to protect the thyroid part highly sensitive to X-rays from strong X-ray irradiation. However, it is different from the filter part F12.

<Highly sensitive irradiation control unit>
12 and 13 are perspective views of a highly sensitive site irradiation regulating unit 36S for protecting the highly sensitive site from X-ray irradiation. FIG. 12 mainly shows the front surface (upstream side on the X-ray path) of the highly sensitive site irradiation regulation unit 36S. FIG. 13 mainly shows the back surface (downstream side on the X-ray path) of the highly sensitive site irradiation regulation unit 36S.

  Both the shielding portions S21 and S22 protect the eyeball, which is one of highly sensitive sites, from X-ray irradiation. The shielding part S21 is used for frontal cephalometric imaging, and the shielding part S22 is used for side cephalometric imaging. Such a highly sensitive site irradiation regulating unit 36S is provided, for example, at an upstream or downstream position in the vicinity of the side dose reduction filter unit 36 or the front dose reduction filter unit on the X-ray path.

  The shielding parts S21 and S22 are configured to be displaced by the drive part of the high-sensitivity part irradiation regulation unit 36S, and are selectively arranged on the optical path of the X-ray according to the front cephalography or the side cephalography. .

  The basic drive structure of the highly sensitive site irradiation regulation unit 36S is the same as that of the dose reduction filter unit 36, but there are some differences as follows. In the highly sensitive site irradiation regulation unit 36S, the shielding portions S21 and S22 are fixed to a common base member S2B, and the base member S2B includes nut members 367S and 367S corresponding to the nut members 367 and 367, and slide members 369 and 369. The slide members 369S and 369S corresponding to are fixed. The nut members 367S and 367S are screwed into the screw shaft 363S corresponding to the screw shaft 363, and the slide members 369S and 369S are slid relative to the shaft 365S corresponding to the shaft 365.

  In the highly sensitive site irradiation regulation unit 36S, the shielding portions S21 and S22 need only be selectively displaced, and there is no need to adjust the opening degree between the two members. For this reason, in this example, the screw shaft 363S corresponding to the screw shaft 363 does not consist of a normal screw and a reverse screw, but only a positive screw.

  FIG. 14 is a diagram showing the position of the shielding part S21 with respect to the front filter parts F13 and F14 at the time of frontal cephalo photographing shown in FIG. FIG. 15 is a diagram illustrating the position of the shielding portion S22 with respect to the side surface filter portions F15 and F16 at the time of side surface cephalo photographing illustrated in FIG. 14 and 15A show an example in which shielding portions S21 and S22 are arranged at the position of X-rays incident on the eyeball.

  The shielding unit S21 shields X-rays directed to the left and right eyeballs in front of the face. The shielding unit S22 shields X-rays directed to the left and right eyeballs on the side of the face. Here, the left and right eyeballs on the side of the face are located almost on the same X-ray path. For this reason, the front shielding part S21 has a shape wider on the left and right than the side shielding part S22. The shielding parts S21 and S22 protect the eyeball, which is one of highly sensitive parts, from X-ray irradiation by being arranged at appropriate positions as shown in the figure.

  Returning to FIG. 1, the main body unit 10 is provided with a subject holding unit 60. The subject holding unit 60 is fixed to the lower frame 19 disposed below the upper frame 14. The lower frame 19 is moved up and down with respect to the support column 18 together with the upper frame 14 by the Z-axis drive motor 165. Here, the subject holding unit 60 includes a chin rest 61 that fixes the head HP1 by placing the chin of the head HP1 of the subject, and an elevating unit 63 that moves the chin rest 61 up and down with respect to the lower frame 19. And. By adjusting the height position of the chin rest 61, the height position in the vertical direction of the region to be imaged in the head HP1 of the subject can be set to the height position of the generator 20 or the CT image or panoramic X-ray image. , And can be adjusted according to the height position of the first detector 30.

  Note that the configuration of the subject holding unit 60 is not limited to the chin rest 61. For example, the subject holding part may be provided with ear rods or the like that are inserted into the holes of both ears of the head HP1 to position the head HP1.

<Main body control unit>
Returning to FIG. 1, the configuration of the main body control unit 70 will be described. The main body control unit 70 is configured by a general computer including a CPU, a ROM, a RAM, and the like. The CPU operates according to a program (not shown), thereby turning the swing arm drive control unit 71, the retreat movement control unit 72, the X-ray restriction control unit 73, the subject position control unit 74, the detector movement control unit 75, and the filter movement control. It operates as a unit 76.

  The turning arm drive control unit 71 controls the turning arm drive unit 16 to control the movement of the turning arm 4 in the x-axis direction and the vertical direction and the turning movement around the turning axis 12.

  In the case of panoramic X-ray imaging or CT imaging, the turning arm drive control unit 71 positions the generator 20 and the first detector 30 at a turning start position corresponding to the imaging target part of each imaging, and then performs a predetermined operation. Follow the trajectory and turn to the turn end position.

  In addition, the swivel arm drive control unit 71 appropriately swivels the swivel arm 4 at the time of cephalometric radiography to accommodate the generator 20 and the first detector as shown in FIG. 3 or FIG. The unit 3 and the second detector 56 are positioned so as to be arranged on the same straight line. Thereby, it is possible to perform head X-ray standard imaging using the head imaging collimator 34 and the dose reduction filter F1 provided in the first detector housing 3.

  The retreat movement control unit 72 moves the first detector 30 between the light receiving position DTP and the retreat position EVP by controlling driving of the motor 321 of the retreat movement mechanism 32. Specifically, during panoramic X-ray imaging and CT imaging using the first detector 30, the retreat movement control unit 72 places the first detector 30 at the light receiving position DTP. Further, at the time of cephalometric radiography using the second detector 56, the retreat movement control unit 72 moves the first detector 30 to the retreat position EVP. Thus, the slit X-ray beam NB1 from the generator 20 can reach the second detector 56 without being blocked by the first detector 30.

  Of the exterior part constituting the first detector housing part 3, the part on the path of the X-ray beam is transmission permissible parts RL1 and RL2 made of a material that does not prevent X-ray transmission. The permissible transmission part RL1 is arranged between the generator 20 and the first detector 30, and the permissible transmission part RL2 is arranged on the part opposite to the permissible transmission part RL1. The permissible transmission part RL2 may be an X-ray transmissive metal plate that functions as a soft X-ray removal filter that removes soft X-rays. By removing soft X-rays, it is possible to remove soft X-rays that are relatively easily absorbed by the subject, thereby reducing the X-ray exposure amount of the subject. The X-ray transparent metal plate is preferably an aluminum plate, a titanium plate, an iron plate, a copper plate, or the like. By making the exterior part of the first detector housing part 3 an X-ray transparent metal plate, a space for installing the soft X-ray removal filter in the first detector housing part 3 becomes unnecessary, and the first detector housing part The thickness of 3 can be reduced. Moreover, it can suppress that the external appearance property and protective property of the 1st detector accommodating part 3 are impaired by comprising an exterior part with a X-ray transparent metal plate.

  If the transmission allowing portions RL1 and RL2 are not provided and the retracting movement mechanism 32 is also omitted, the first arm from the generator 20 to the second detector 56 can be tilted by tilting the swivel arm 4 from the first on the X-ray beam path. If the detector accommodating portion 3 is retracted, it is conceivable to perform cephalometric radiography. However, in this case, in order to make the X-ray beam from the generator 20 incident on the detection surface of the second detector 56 at a substantially right angle, a rotation mechanism for rotating the generator 20 relative to the swivel arm 4 is separately required. Become. Since the medical X-ray imaging apparatus 1 includes the permissible transmission portions RL1 and RL2 and the retract movement mechanism 32, an X-ray beam is passed through the first detector housing 3 when performing X-ray standard imaging. The head HP1 can be irradiated. That is, since it is not necessary to provide a rotation mechanism for rotating the generator 20, the configuration of the generator housing 2 can be simplified.

  The X-ray restriction control unit 73 controls the generator side collimator 22 and the head imaging collimator 34. The X-ray restriction control unit 73 changes the irradiation range or irradiation direction of the X-ray beam B1 according to the type of imaging in accordance with the type of imaging. For example, in the case of panoramic X-ray imaging, the X-ray restriction control unit 73 controls the generator-side collimator 22 to form a slit X-ray beam. In the case of CT imaging, the X-ray restriction control unit 73 controls the generator-side collimator 22 to form an X-ray cone beam. In the case of head X-ray standard imaging, the X-ray restriction control unit 73 controls the generator-side collimator 22 and the head imaging collimator 34 to form the slit X-ray beam NB1 and the slit X-ray. The head HP1 is scanned by changing the irradiation direction of the line beam NB1 in the x-axis direction (see FIG. 4).

  The detector movement control unit 75 drives the motor 583 of the detector moving mechanism 58 to move the second detector 56 in the x-axis direction. In the head X-ray standard imaging, the slit X-ray beam NB1 moves in the x-axis direction, so the detector movement control unit 75 follows the movement of the slit X-ray beam NB1 and moves the second detector 56 to the x-axis. By moving in the direction, X-rays are received.

  The filter movement control unit 76 controls the operation of the motor 361 of the dose reduction filter moving mechanism 360 in the dose reduction filter unit 36 shown in FIG. For example, as shown in FIG. 16, when cephalometric radiography is performed in which the side surface of the head HP1 is imaged, the filter units F11 and F12 of the dose reduction filter F1 according to the position of the soft tissue on the side surface of the head HP1. The position of each measurement point of the head HP1 is detected by the measurement unit 525.

  By detecting the positions of the pair of ear rods 521 and 521 and the nadion contact part 523, the positions of the ear holes and nadion in the head HP1 can be specified, and the approximate position of the soft tissue in the head HP1 can be specified. Become. The filter movement control unit 76 controls the dose reduction filter unit 36 based on the detection result by the measurement unit 525. As a result, the dose reduction filter F1 can be disposed at a preferable position, and head X-ray standard imaging can be performed satisfactorily. Note that the measurement unit 525 is not necessarily required. For example, a scale indicating the position of the pair of ear rods 521, 521 or the nadion contact portion 523 is attached to the head fixing unit 52 in advance, and the value indicated by the scale is used. The operator may read it. The operator may input the read numerical value via the operation unit 80 or the like, and the filter movement control unit 76 may acquire the value.

  The subject position control unit 74 controls the vertical position of the subject (here, the head HP1) by driving the elevating unit 63 of the subject holding unit 60 to raise and lower the chin rest 61. Specifically, the vertical direction of the chin rest 61 is different so that the incident angle of the center (center beam) of the X-ray beam to the detection surface of the first detector 30 differs between panoramic X-ray imaging and CT imaging. The height position is adjusted as appropriate. This position adjustment will be described with reference to FIGS. FIG. 17 is a front view showing the medical X-ray imaging apparatus 1 during panoramic X-ray imaging. FIG. 18 is a front view showing the medical X-ray imaging apparatus 1 during CT imaging.

  As shown in FIG. 17, in the case of panoramic X-ray imaging, a slit X-ray beam PNB1 is formed by the generator-side collimator 22 and irradiated on the jaw of the head HP1. In general, it is desirable that the line of sight when observing a tooth from the lingual side (inner mouth side) to the cheek side or vice versa is orthogonal to the tooth axis. It is desirable that the viewing direction is slightly upward with respect to the horizontal plane. Therefore, in panoramic X-ray imaging, as shown in FIG. 17, the center of the slit X-ray beam PNB1 (center beam PNBC1) is upward with respect to the direction perpendicular to the turning axis 12 (here, the y-axis direction). The slit X-ray beam PNB1 is applied to the jaw part of the head HP1. For this reason, the incident angle AGU of the center beam PNBC1 with respect to the detection surface of the first detector 30 is an acute angle. Further, the height position of the chin rest 61 is adjusted so that such a slit X-ray beam PNB1 can be irradiated to each part of the jaw. Thus, a good panoramic image can be acquired by irradiating the slit X-ray beam PNB1 slightly upward during panoramic X-ray imaging.

  On the other hand, as shown in FIG. 18, in the case of CT imaging, an X-ray cone beam CB1 is formed by the generator-side collimator 22 and irradiated to the imaging target site such as the entire jaw part or a part of the head HP1. In CT imaging, the center of the X-ray cone beam CB 1 (center beam CBC 1) is the y-axis direction perpendicular to the turning axis 12. For this reason, the incident angle AGU of the center beam CBC1 with respect to the detection surface of the first detector 30 is perpendicular. The incident angle AGU may be substantially orthogonal even if not strictly orthogonal. Then, the height position of the chin rest 61 is adjusted so that the center of the X-ray cone beam CB1 (center beam CBC1) passes through the center of the imaging target region.

<Image processing unit>
Returning to FIG. 1, the image processing unit 90 is configured by a general computer including a CPU, a ROM, a RAM, and the like. The image processing unit 90 may be configured as a computer different from the main body control unit 70, but may be a functional module realized by software by the CPU of the main body control unit 70 operating according to a program. . The image processing unit 90 generates various X-ray images (CT image, panoramic image, and head X-ray standard image) from projection data obtained by X-ray imaging performed by the main body unit 10.

<Operation unit>
The operation unit 80 includes an operation panel 81 and an X-ray irradiation command switch 83. The operation panel 81 includes a shooting mode selection unit 811, a swing arm raising / lowering operation unit 813, a shooting region setting unit 815, and a physique setting unit 817. The operation panel 81 includes a touch panel type screen, and is configured with buttons for virtually displaying each unit such as the shooting mode selection unit 811 on the screen. The operation panel 81 may include a plurality of physical buttons that can be operated by the operator. In this case, each unit such as the shooting mode selection unit 811 may be configured with physical buttons.

  The imaging mode selection unit 811 is configured so that the main body unit 10 operates from each imaging mode in which panoramic X-ray imaging (first imaging), CT imaging (first imaging), and cephalometric X-ray standard imaging (second imaging) are performed. The selection of a specific shooting mode to be executed is accepted. For example, when the cephalometric radiography mode is selected, the retract movement mechanism 32 moves the first detector 30 to the retract position. Then, cephalometric radiography is performed using the second detector 56. As described above, when the operator selects the imaging mode, it is easy to automatically operate the medical X-ray imaging apparatus so as to perform imaging according to the selected imaging mode. For this reason, operation of the medical X-ray imaging apparatus 1 can be facilitated.

  The swing arm lifting / lowering operation unit 813 is an input unit that is operated when the swing arm 4 is lifted / lowered in the vertical direction.

  The imaging region setting unit 815 is an input unit that is operated when setting an imaging target region when performing X-ray imaging. The imaging region setting unit 815 is configured to accept selection of a specific imaging target part from among a plurality of predetermined imaging target parts, for example. Here, the plurality of imaging target parts include, for example, a part of the head HP1 such as the upper jaw, the lower jaw, the upper right jaw or the left upper jaw and the entire head HP1. In this case, imaging conditions suitable for each imaging target region are stored in advance in the storage unit 92 or the like, and imaging condition options corresponding to the selected imaging target region are called. The imaging conditions include, for example, the position of the turning arm 4, the turning arm 4 (turning angle), the size of the irradiation field, and the like at the time of imaging in CT imaging. Note that the imaging region setting unit 815 may be configured so that an image imitating a subject is displayed on the image display monitor 94 and the operator can arbitrarily specify an imaging target region on the image.

  The physique setting unit 817 is an input unit operated to set the size of a subject to be photographed. For example, the physique setting unit 817 is configured to accept selection of a physique close to the subject from a physique corresponding to an adult male, a physique corresponding to an adult female, or a physique corresponding to a child. Further, the physique setting unit 817 may be configured to accept input of parameters such as height and weight. Since the physique setting unit 817 sets the physique of the subject, the three-dimensional coordinate position of the imaging target region set by the imaging region setting unit 815 can be specified with high accuracy, so a more desirable X-ray image can be obtained. It can be acquired.

  The X-ray irradiation command switch 83 is an input unit that is pressed by an operator when starting X-ray irradiation in each X-ray imaging. For example, in CT imaging, when the X-ray irradiation command switch 83 is operated, the turning arm 4 is turned and the X-ray irradiation to the subject is simultaneously performed. Note that the X-ray irradiation command switch 83 may be configured as a so-called deadman switch that stops the turning of the swing arm 4 and stops the X-ray irradiation on the subject when the operator releases the finger. In addition, as an aspect which stops X-ray irradiation, the aspect which stops the electric power supply to the X-ray tube of the generator 20, or the aspect which shields X-rays by a shielding member (generator side collimator 22 etc.), etc. are considered. It is done.

  The image display monitor 94 is composed of, for example, a liquid crystal display and displays the X-ray image generated by the image processing unit 90.

<Operation>
FIG. 19 is a flowchart showing the operation of the medical X-ray imaging apparatus 1 according to the first embodiment. The operation of the medical X-ray imaging apparatus 1 shown in FIG. 19 is executed under the control of the main body control unit 70 unless otherwise specified.

  First, an X-ray imaging mode executed by the medical X-ray imaging apparatus 1 is selected via the imaging mode selection unit 811 (step S10). Here, one imaging mode can be selected from the panoramic X-ray imaging mode, the CT imaging mode, and the head X-ray standard imaging mode.

<Panorama X-ray mode>
First, the operation of the medical X-ray imaging apparatus 1 in the panoramic X-ray imaging mode will be described. In step S10, when the panoramic X-ray imaging mode is selected, the turning arm 4 turns so that the orientation of the turning arm 4 is in a posture for introducing the subject (step S100). After step S100, the subject is introduced into the main body 10. Subsequently, the vertical position of the swing arm 4 is adjusted, and the vertical position of the subject's head HP1 is adjusted by adjusting the height of the chin rest 61 (step S101). . In addition, when the initial position of the chin rest 61 is for panoramic X-ray photography, the position adjustment of the chin rest 61 can be omitted.

  Next, the revolving arm 4 revolves and moves horizontally to move to a predetermined shooting start position (step S102). As a result, the generator 20 is arranged at the movement start position on the panoramic X-ray imaging trajectory. Subsequently, the first detector 30 is disposed at the light receiving position DTP (step S103). When the first detector 30 is disposed at a position different from the light receiving position DTP (for example, the retracted position EVP), the retracting movement mechanism 32 is driven, and the first detector 30 moves to the light receiving position DTP. In addition, the opening 226 of the generator-side collimator 22 is adjusted so as to form a slit X-ray beam PNB1 for panoramic X-ray imaging (step S104).

  Subsequently, an imaging start command is accepted (step S105). Here, the main body control unit 70 monitors whether or not the X-ray irradiation command switch 83 has been operated. When the main body control unit 70 receives an imaging start command by operating the X-ray irradiation command switch 83, the main body control unit 70 causes the main body unit 10 to perform panoramic X-ray imaging (step S106). Although not described in detail, a strip-like projection image is acquired at a predetermined frame rate by the first detector 30 while the generator 20 is moved on the panoramic X-ray imaging trajectory. One panoramic image is generated by the image processing unit 90 joining the strip-shaped projection images.

<Head X-ray standard imaging mode>
Next, the operation of the medical X-ray imaging apparatus 1 in the head X-ray standard imaging mode will be described. When the head X-ray standard imaging mode is selected in step S10, the direction of the turning arm 4 is changed for the head X-ray standard imaging (step S200). That is, as shown in FIG. 4, the swing arm 4 rotates so that the generator 20, the first detector housing portion 3, and the second detector 56 are aligned.

  Subsequently, the vertical position of the swing arm 4 is adjusted so that the X-rays emitted from the generator 20 can pass through the head HP1 and enter the second detector 56 (step S201). .

  Subsequently, the shooting direction and shooting area of the head HP1 are set (step S202). The medical X-ray imaging apparatus 1 is configured to be capable of performing side cephalometric imaging for imaging the head HP1 from the side and front cephalometric imaging for imaging the head HP1 from the front. Therefore, in step S200, it is set via the imaging region setting unit 815 of the operation unit 80 whether to perform side cephalometric imaging or frontal cephalometric imaging. Note that the medical X-ray imaging apparatus 1 may be configured to be capable of executing only one of side cephalometric imaging and front cephalometric imaging. In such a case, the setting of the shooting direction can be omitted.

  FIG. 20 is a conceptual diagram for explaining an imaging region in cephalometric radiography. As shown in FIG. 20, in the medical X-ray imaging apparatus 1, a region WR1 including the entire head HP1 is used as an imaging region, and a region PR1 of a part of the head HP1 (mainly the maxillofacial area here) is imaged. It is possible to set the area. As described above, by allowing the size of the imaging region to be variably set in step S202, the X-ray irradiation range can be limited to a necessary range, so that the X-ray exposure of the subject can be reduced.

  Returning to FIG. 19, the positions of soft tissue and hard tissue are detected (step S203). Then, the position of the dose reduction filter F1 is adjusted according to the detected position (step S204). Here, as described above, the position of the measurement point on the head HP1 is detected by the measurement unit 525 of the head fixing unit 52, and the positions of the soft tissue and the hard tissue on the head HP1 are estimated. And the dose reduction filter F1 is arrange | positioned according to the estimated position. Specifically, as described with reference to FIGS. 9 and 16, the dose reduction filter F1 is disposed on the optical path of the X-ray from the generator 20 to the estimated soft tissue position.

  Subsequently, when the first detector 30 is at a position other than the retracted position EVP (for example, the light receiving position DTP), the retracting mechanism 32 is driven to move the first detector 30 to the retracted position EVP. (Step S205). Thus, the first detector 30 is retracted from the optical path from the generator 20 to the second detector 56. Further, when the detector moving mechanism 58 is driven, the second detector 56 moves to the movement start position (step S206). As described above, in cephalometric radiography, the second detector 56 moves in the x-axis direction in accordance with the movement of the slit X-ray beam NB1 along the x-axis direction (see FIG. 4). In step S17b, the second detector 56 moves to the starting position when starting to move in the x-axis direction.

  Subsequently, the position of the opening 34S of the head photographing collimator 34 is adjusted (step S207). Since the head HP1 is scanned with the slit X-ray beam NB1 formed by the opening 34S of the head photographing collimator 34, the position of the opening 34S is set as a position at which scanning is started (scanning start position).

  Further, the size and position of the opening 226 of the generator-side collimator 22 are adjusted (step S208). Specifically, the size of the opening 226 is adjusted so that the X-ray beam from the generator 20 is irradiated in a slightly wider range in the y-axis direction than the opening 34S of the head imaging collimator 34. For example, as shown in FIG. 20, when a partial region PR1 of the head HP1 is used as the imaging region, the vertical length of the opening 226 of the generator-side collimator 22 is set to the vertical length of the region PR1. Also limited. As a result, only the region PR1 can be irradiated with the X-ray beam. Further, the position of the opening 226 is adjusted to be a position corresponding to the scanning start position of the opening 34S of the head imaging collimator 34 (that is, the position on the optical path of the X-ray beam from the generator 20 to the opening 34S). Is done.

  Subsequently, an imaging start command is received (step S209). Here, the main body control unit 70 monitors whether or not the X-ray irradiation command switch 83 has been operated. When the main body control unit 70 accepts an imaging start command by operating the X-ray irradiation command switch 83, the main body control unit 70 causes the main body unit 10 to perform head X-ray standard imaging (step S210). More specifically, the aperture 226 of the generator-side collimator 22 and the aperture 34S of the head imaging collimator 34 are synchronously moved in the y-axis direction, thereby scanning the imaging area of the head HP1 with the slit X-ray beam NB1. Is done. Moreover, the X-ray which permeate | transmitted head HP1 is detected because the 2nd detector 56 moves to a y-axis direction according to the movement of the slit X-ray beam NB1. Then, the image processing unit 90 joins the projection data (here, a plurality of strip-shaped projection images) acquired by the main body unit 10 in the scanning direction (y-axis direction), so that one cephalometric X-ray standard is obtained. A photo is generated.

<CT imaging mode>
Next, the operation of the medical X-ray imaging apparatus 1 in the CT imaging mode will be described. When the CT imaging mode is selected in step S10, the turning arm 4 is turned so that the orientation of the turning arm 4 assumes a posture for introducing the subject (step S300). Then, after step S300, the subject is introduced into the main body 10. Subsequently, the vertical height position of the turning arm 4 is adjusted, and the vertical height position of the subject's head HP1 is adjusted by adjusting the height of the chin rest 61 (step S301). .

  Subsequently, the imaging area setting unit 815 receives the setting of the CT imaging area (step S302). Specifically, the imaging region setting unit 815 accepts selection of a specific imaging target region from a plurality of imaging target regions. Then, the region to be imaged received by the imaging region setting unit 815 is set as the CT imaging region.

  Subsequently, the swivel arm 4 is swung and horizontally moved to move to a predetermined shooting start position (step S303). Thereby, the generator 20 is arranged at the turning start position on the CT imaging trajectory. Further, the vertical height position of the swivel arm 4 or the height position of the head HP1 held by the chin rest 61 is adjusted in accordance with the vertical height of the CT imaging region set in step S302. (Step S304).

  Subsequently, the first detector 30 is disposed at the light receiving position DTP (step S305). When the first detector 30 is placed and placed at a position different from the light receiving position DTP (for example, the retracted position EVP), the retract moving mechanism 32 is driven, and the first detector 30 moves to the light receiving position DTP. Further, the opening 226 of the generator-side collimator 22 is adjusted so as to form an X-ray cone beam CB1 for CT imaging (step S306). The size of the opening 226 is adjusted so that the irradiation field of the X-ray cone beam CB1 with respect to the head HP1 matches the CT imaging region set in step S302.

  Subsequently, an imaging start command is received (step S307). Here, the main body control unit 70 monitors whether or not the X-ray irradiation command switch 83 has been operated. When the main body control unit 70 receives an imaging start command by operating the X-ray irradiation command switch 83, the main body control unit 70 causes the main body unit 10 to perform CT imaging (step S308). Although details are omitted, the generator 20 and the first detector 30 are rotated by 180 ° or more about the center of the imaging target region. Then, the first detector 30 detects X-rays, whereby a projection image is acquired at a predetermined frame rate. The image processing unit 90 reconstructs the plurality of acquired projection images, thereby generating a CT image at an arbitrary tomographic position.

<Effect>
As described above, in the medical X-ray imaging apparatus 1, the range of the X-ray beam emitted from the generator 20 is arranged on the way to the second detector 56 during cephalometric radiography. It is regulated by the head photographing collimator 34 of the first detector housing 3. For this reason, compared with the case where the spread of the X-ray beam B1 is regulated in the vicinity of the generator 20, the influence of the scattered radiation in the X-ray projection image can be reduced, and the spread of the X-ray beam B1 can be regulated with higher accuracy. For this reason, a head X-ray standard photograph can be acquired favorably. Furthermore, the space for the medical X-ray imaging apparatus 1 can be saved by housing and integrating the head imaging collimator 34 in the first detector housing unit 3 housing the first detector 30. it can.

<2. Second Embodiment>
Next, a medical X-ray imaging apparatus 1A according to the second embodiment will be described. The medical X-ray imaging apparatus 1 according to the first embodiment employs a scanning method that scans the head HP1 with the slit X-ray beam NB1 when acquiring a head X-ray standard photograph. On the other hand, the medical X-ray imaging apparatus 1A obtains a head X-ray standard photograph by simultaneously irradiating the entire imaging target region of the head HP1 with X-rays. Hereinafter, this cephalometric radiography method is referred to as a one-shot method. The one-shot head X-ray standard imaging has the advantage that the imaging time can be shortened and image processing is not particularly required compared to the scanning system.

  FIG. 21 is a front view showing a medical X-ray imaging apparatus 1A according to the second embodiment. FIG. 22 is a plan view showing a medical X-ray imaging apparatus 1A according to the second embodiment. FIG. 23 is a front view showing the head photographing collimator 34A as seen from the EE cross-sectional position shown in FIG. FIG. 24 is a schematic plan view showing a pair of movable shielding plates 383 and 383 according to the second embodiment. In the following description, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the medical X-ray imaging apparatus 1 </ b> A, a head imaging collimator 34 </ b> A that regulates the spread of an X-ray beam for head X-ray standard imaging is housed in the first detector housing 3, and X It is arranged on the path of the line beam. The head imaging collimator 34A is configured to variably regulate the spread of the X-ray beam according to the size of the imaging target region. The head imaging collimator 34A is an example of a single-shot irradiation collimator that forms a wide-area X-ray beam that simultaneously irradiates the entire imaging target region with X-rays.

  Specifically, as shown in FIG. 22, the head photographing collimator 34A includes a pair of immovable shielding plates 381 and 381 arranged apart in the z-axis direction and a pair arranged with a gap in the x-axis direction. Movable shielding plates 383 and 383 and a shielding plate moving mechanism 385 for moving the movable shielding plates 383 and 383 in the x-axis direction.

  The non-moving shielding plates 381 and 381 are substantially rectangular plate-like members arranged so that the x-axis direction is long. The non-moving shielding plates 381 and 381 are provided so as not to move with respect to the first detector housing 3 by fixing both the + x side and −x side both ends to the first detector housing 3, for example. ing.

  The movable shielding plates 383 and 383 are configured as substantially rectangular plate-like members arranged so that the z-axis direction is the longitudinal direction. The movable shielding plates 383 and 383 can be moved by the shielding plate moving mechanism 385 so that the distance between them can be adjusted.

  Specifically, the shielding plate moving mechanism 385 includes a motor 386, a screw shaft 387, and a shaft member 388. The motor 386 is configured to rotate forward or backward about a screw shaft 387 extending in the x-axis direction. A nut member 383 a attached to each upper end portion of the movable shielding plates 383 and 383 is screwed to the screw shaft 387. The shaft member 388 is a rod-shaped member extending in the x-axis direction and is fixed to the first detector housing 3.

  The portion of the screw shaft 387 into which the nut member 383a of the movable shielding plate 383 arranged on the + x side is screwed is a positive screw 387a, and the nut member 383a of the movable shielding plate 383 arranged on the −x side is screwed on The portion of the screw shaft 387 to be turned is a reverse screw 387b. For this reason, when the screw shaft 387 rotates by driving the motor 386, the two nut members 383a move in opposite directions along the x-axis direction. As a result, the two movable shielding plates 383 and 383 move in opposite directions along the x-axis direction.

  A slide member 383b is attached to the lower end of each movable shielding plate 383, 383. Each slide member 383b has a through-hole penetrating in the x-axis direction, and a shaft member 388 is inserted through the through-hole. For this reason, when the screw shaft 387 is rotated by the slide member 383b, the movable shielding plates 383 and 383 are prevented from rotating around the screw shaft 387. Further, since the moving direction of each slide member 383b is limited to only the x-axis direction in which the shaft member 388 extends, the moving direction of each movable shielding plate 383, 383 is also restricted to only the x-axis direction.

  In the example shown in FIG. 21, the spread of the X-ray beam is changed between the head HP1a arranged to perform side cephalometric imaging and the head HP1b arranged to perform frontal cephalometric imaging. In this example, the first broadening side X-ray beam SCB1 for the head HP1a and the second broadening front X-ray beam narrower in the x-axis direction than the first spread for the head HP1b. FCB1 is irradiated.

  More specifically, as shown in FIG. 24, the distance between the pair of movable shielding plates 383 and 383 is set to D1 in the case of side surface cephalo shooting and is set to D2 that is narrower than D1 in the case of front shooting. As described above, in this embodiment, by moving the movable shielding plates 383 and 383, the amount of restriction of the spread of the X-ray beam is adjusted so as to match the size of the region to be imaged during cephalometric radiography. Is done.

  Note that the head imaging collimator 34A is configured to be able to adjust the amount of restriction in the X-ray beam spreading only in the x-axis direction. However, by making the immovable shielding plates 381 and 381 movable in the z-axis direction, the amount of restriction on the spread in the z-axis direction may be adjustable. However, it is possible to variably regulate the spread of the X-ray beam in the z-axis direction by the generator-side collimator 22 (see FIG. 2).

  FIG. 25 is a front view showing the second detector 56A viewed from the FF cross-sectional position shown in FIG. The second detector 56A according to this embodiment is fixed to the second detector housing portion 54, and the detection surface 561A is substantially square or substantially rectangular. The detection surface 561A is wide enough to receive an X-ray beam (for example, the side X-ray beam SCB1, the front X-ray beam FCB1, etc.) at a time. Thus, in the present embodiment, the second detector 56A has a sufficiently wide detection surface 561A. For this reason, in the medical X-ray imaging apparatus 1A, it is not necessary to move the second detector 56A. Therefore, in the medical X-ray imaging apparatus 1A, a moving mechanism (detector moving mechanism 58) that moves the second detector 56 provided in the medical X-ray imaging apparatus 1 and a control unit (detection) that controls the movement. The instrument movement control unit 75) is omitted. The detection surface 561A of the second detector 56A is an example of a wide area detection surface that detects a wide area X-ray beam transmitted through the imaging target area of the head HP1 at a time.

<Operation>
FIG. 26 is a flowchart showing the operation of the medical X-ray imaging apparatus 1A according to the second embodiment. In the medical X-ray imaging apparatus 1A, as in the medical X-ray imaging apparatus 1, a specific imaging mode is selected from the panoramic X-ray imaging mode, the CT imaging mode, and the head X-ray standard imaging mode. (Step S10). Then, each X-ray imaging flow is executed according to the selected imaging mode.

  The flow of panoramic X-ray imaging and the flow of CT imaging (first imaging) in the medical X-ray imaging apparatus 1A are the flow of panoramic X-ray imaging (step S100 to step S106) and the flow of CT imaging (steps) shown in FIG. S300 to step S308) are substantially the same. Further, the flow of cephalometric radiography in the medical X-ray imaging apparatus 1A is substantially the same as the cephalometric radiography flow (steps S200 to S210) shown in FIG. However, in this flow, since the second detector 56A is stationary, step S206 is omitted. In this flow, not only the position of the opening but also the size of the opening of the head photographing collimator 34A is adjusted (step S207A).

<Effect>
In the medical X-ray imaging apparatus 1A, at the time of cephalometric X-ray imaging, the X-axis direction spread of the X-ray beam emitted from the generator 20 is arranged in the middle of the path to the second detector 56A. It can be regulated by the head photographing collimator 34 </ b> A of the one detector housing 3. As a result, the amount of restriction can be reduced as compared with the case where the spread of the X-ray beam is restricted in the vicinity of the second detector 56, so that the restriction member can be reduced in size. In addition, since the influence of scattering is reduced as compared with the case where the spread of X-rays is regulated in the vicinity of the generator 20, the spread of the X-ray beam can be regulated with high accuracy. Therefore, a cephalometric radiogram can be acquired satisfactorily.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention. In addition, the configurations described in the above embodiments and modifications can be appropriately combined or omitted as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1,1A Medical X-ray imaging apparatus 10 Main-body part 12 Rotating shaft 14 Upper frame 16 Rotating arm drive part 167 Rotation drive part 2 Generator accommodating part 20 Generator 22 Generator side collimator (X-ray control part)
3 First detector housing unit 30 First detector 32 Retraction moving mechanism 34 Head photographing collimator (slit collimator)
34A Head imaging collimator (injection collimator)
34S opening (slit)
36 Dose reduction filter unit 360 Dose reduction filter moving mechanism 4 Swivel arm 5 Cephalo unit 50 Arm 52 Head fixing unit 525 Measurement unit 54 Second detector housing unit 56, 56A Second detector 561 Detection surface (elongated detection surface)
561A Detection surface 58 Detector moving mechanism (detection surface moving mechanism)
60 Subject Holding Unit 70 Body Control Unit 71 Swing Arm Drive Control Unit (Turning Control Unit)
72 Evacuation Movement Control Unit 73 X-ray Restriction Control Unit 74 Subject Position Control Unit 75 Detector Movement Control Unit 76 Filter Movement Control Unit 80 Operation Unit 811 Imaging Mode Selection Unit 815 Imaging Area Setting Unit 90 Image Processing Unit 92 Storage Unit 94 Image Display Monitor AGU Incident angle B1 X-ray beam CB1 X-ray cone beam CBC1 Center beam CBX1 X-ray cone beam DTP Light receiving position EVP Retreat position F1 Dose reduction filter FCB1 Front X-ray beam HP1, HP1a, HP1b Head NB1 Head X-ray Slit X-ray beam for standard radiography PNB1 Slit X-ray beam for panoramic X-ray radiography RL1, RL3 Transmission permissible part RL2 Transmission permissible part (soft X-ray removal filter, X-ray transparent metal plate)

Claims (15)

A generator for generating an X-ray beam;
A detector accommodating portion for accommodating therein a first detector for detecting the X-ray beam from the generator;
A support part that supports the generator and the detector housing so that the generator and the first detector can be opposed to each other;
A turning drive for turning the support;
A second detector for detecting the X-ray beam transmitted through the head during X-ray standard imaging for X-ray imaging of the head;
A head fixing portion for fixing the head at the time of the head X-ray standard imaging;
With
The first detector is configured to be able to perform a first imaging in which the X-ray beam is received and imaged, and the second detector is configured to perform a second imaging in which the X-ray standard image is received by receiving the X-ray beam. A medical X-ray imaging apparatus,
A turning drive control unit for controlling the turning drive unit so that the detector housing is positioned between the generator and the second detector during the second imaging;
A light receiving position for receiving the X-ray beam during the first imaging, and a retracting position for retracting the first detector from the optical path of the X-ray beam directed to the second detector during the second imaging. And a retracting movement mechanism for moving between
The detector accommodating portion is
An X-ray restricting unit for head imaging that restricts the spread of the X-ray beam from the generator toward the second detector;
Constituting an exterior part of the detector housing part, a transmission allowing part for transmitting the X-ray beam from the generator toward the second detector;
A medical X-ray imaging apparatus comprising: The medical X-ray imaging apparatus according to claim 1,
The X-ray restricting section for head imaging is a medical X-ray imaging apparatus that variably regulates the spread of the X-ray beam toward the second detector. The medical X-ray imaging apparatus according to claim 1 or 2,
The medical X-ray imaging apparatus, wherein the head imaging X-ray restricting unit suppresses irradiation of the X-ray beam to a region of the head excluding the maxillofacial surface. The medical X-ray imaging apparatus according to any one of claims 1 to 3,
The X-ray restricting unit for head imaging is
A slit collimator for forming an X-ray slit beam by a slit extending in one direction for the X-ray;
A slit moving mechanism that scans an imaging target region with the slit beam by moving the slit, and
The second detector is
An elongated detection surface for detecting the slit beam;
A medical X-ray imaging apparatus comprising: a detection surface moving mechanism that moves the elongated detection surface in synchronization with the movement of the slit beam. The medical X-ray imaging apparatus according to any one of claims 1 to 3,
The X-ray restricting unit for head imaging is
A single-irradiation collimator that forms a wide-area X-ray beam that simultaneously irradiates the X-rays to the entire imaging target region in the head by regulating the X-rays;
With
The second detector is
A wide-area detection surface for detecting the wide-area X-ray beam transmitted through the imaging target area at a time;
A medical X-ray imaging apparatus comprising: The medical X-ray imaging apparatus according to claim 5,
The single-irradiation collimator changes a restriction amount for restricting the spread of the X-ray beam between the case of photographing the front of the head and the case of photographing the side of the head in the second photographing. Medical X-ray imaging device. The medical X-ray imaging apparatus according to any one of claims 1 to 6,
A shooting mode selection receiving unit for receiving selection of a specific shooting mode from a plurality of shooting modes including a first shooting mode for executing the first shooting and a second shooting mode for executing the second shooting;
Further comprising
The medical X-ray imaging apparatus in which the retracting movement mechanism moves the first detector to the retracted position when the imaging mode selection receiving unit receives the selection of the second imaging mode. The medical X-ray imaging apparatus according to claim 7,
The generator is housed inside, and the generator housing part supported by the support part;
An X-ray restricting portion that is accommodated inside the generator accommodating portion and restricts an irradiation range by shielding the X-ray emitted from the generator by a shielding plate;
Further comprising
A medical X-ray imaging apparatus in which an irradiation range of the X-ray beam is changed by the X-ray restricting unit moving the shielding plate according to an imaging mode received by the imaging mode selection receiving unit. The medical X-ray imaging apparatus according to any one of claims 1 to 8,
The medical X-ray imaging apparatus, wherein the first imaging is at least one of panoramic X-ray imaging and CT imaging. The medical X-ray imaging apparatus according to claim 8,
The first imaging includes panoramic X-ray imaging and CT imaging,
The X-ray restricting unit restricts the X-ray so that the detection surface of the first detector is irradiated upward in the panoramic X-ray imaging, and the detector of the first detector in the CT imaging. A medical X-ray imaging apparatus that regulates the X-ray so as to be incident at right angles to the X-ray. The medical X-ray imaging apparatus according to any one of claims 1 to 10,
The swivel drive part swivels the support part around a swivel axis set at a position between the generator and the detector housing part,
The medical X-ray imaging apparatus, wherein the retracting movement mechanism moves the first detector along the axial direction of the pivot axis. The medical X-ray imaging apparatus according to any one of claims 1 to 11,
A dose reduction filter that is housed in the detector housing portion and that reduces a portion of the X-ray beam directed to the second detector;
A medical X-ray imaging apparatus further comprising: The medical X-ray imaging apparatus according to claim 12,
A dose reduction filter moving mechanism that is housed in the detector housing and moves the dose reduction filter in accordance with the position of the soft tissue in the head;
A medical X-ray imaging apparatus further comprising: The medical X-ray imaging apparatus according to any one of claims 1 to 13,
A medical X-ray imaging apparatus, further comprising: a soft X-ray removal filter that is provided in the detector housing portion and removes soft X-rays of the X-ray beam directed toward the second detector. The medical X-ray imaging apparatus according to claim 14,
A medical X-ray imaging apparatus, wherein the soft X-ray removal filter is an X-ray transmissive metal plate that constitutes the transmission allowing portion.

Images