WO2015125589A1 - X-ray imaging apparatus - Google Patents

Abstract

The present invention relates to an X-ray panorama imaging apparatus equipped with an X-ray tube arm and a detector arm that rotate centered on a central axis (CA) independently of each other. The X-ray tube arm is provided with a tube-housing section (21A), which houses the X-ray tube (23), and a tube support section (21L), which supports said tube-housing section so as to be rotatable around a first axis (AXs) that is parallel to the central axis. The detector arm is provided with a detector-housing section (22A), which houses the detector (24), and a detector support section (22L), which supports the detector-housing section so as to be rotatable around a second axis (Axd) that is parallel to the central axis. During scanning, the respective driving means are controlled according to mutually independent rotation speed patterns. It is possible to teach the limits of a partial imaging using a laser beam from an arm (25) that simulates actual X-ray irradiation and the results thereof are reflected in 4-axis control actions. The present invention also relates to a portable imaging apparatus provided with a mechanism for blocking X-rays from being scattered outside the imaging space or a mechanism for positioning on a dental treatment chair.

Description

X-ray equipment

The present invention relates to an X-ray imaging apparatus using X-rays, and in particular, faces an X-ray tube and a detector that detects X-rays irradiated from the X-ray tube and transmitted through an imaging region of a subject. And an X-ray imaging apparatus having a structure for rotating the X-ray tube and the detector around a subject.

In recent years, tomography of subjects based on the tomosynthesis method has become popular. Although the principle of this tomosynthesis method has been known for a long time (see, for example, Patent Document 1), in recent years, a tomographic method has also been proposed in which it is desired to enjoy the simplicity of image reconstruction based on the tomosynthesis method. (For example, see Patent Document 2 and Patent Document 3). In addition, many examples are seen for dental use (see, for example, Patent Document 4 and Patent Document 5).

As one of the applications of the tomosynthesis method to dentistry, a panoramic imaging apparatus that obtains a panoramic image in which a curved dentition is developed in a two-dimensional plane has been put into practical use. This panoramic imaging apparatus normally has a pair of an X-ray tube and a detector having vertically long two-dimensionally arranged pixels around the oral cavity of a subject along a dentition whose rotation center is assumed. A mechanism for rotating the center of rotation in a complicated manner so as to draw a trajectory is provided. A constant value is maintained between the X-ray tube and the detector. The above-described constant trajectory is a trajectory for focusing on a reference tomographic plane (a tomographic plane existing three-dimensionally) set in advance along a dentition regarded as a standard shape and size. During this rotation, X-rays emitted from the X-ray tube are transmitted through the subject at regular intervals, and detected as digital frame data by the detector. For this reason, frame data focused on the reference tomographic plane is collected at regular intervals. This frame data is reconstructed by the tomosynthesis method to obtain a panoramic image of the reference tomographic plane.

Further, Patent Document 6 discloses an example of a panoramic imaging apparatus having an imaging system in which an X-ray tube and a detector can both rotate independently of each other so as to form a circular orbit around the same center point. . The jaw is positioned in the circular orbit. The velocity pattern of the X-ray tube and the detector is controlled so that the X-ray irradiated from the X-ray tube always faces the detection surface of the detector.

JP-A-57-203430 JP-A-6-88790 JP-A-10-295680 US Patent Publication US2006 / 0203959 A1 JP2007-136163A International Publication WO2012 / 008492

However, in the case of the apparatus described in Patent Document 6 described above, the X-ray tube and the detector are mounted at corresponding positions passing through one rotation center on the same trajectory. There were still restrictions on the setting of the tomographic plane (focal plane). In other words, since the dentition of the subject varies from person to person, a higher degree of freedom is desired for setting the focal plane, but such a request has not been met.

Furthermore, a high degree of freedom is desired by setting a partial focal plane aiming at a desired number of teeth, but such a request has not been met.

In the medical field, treatment methods that follow the experience and techniques accumulated over many years are easy for the surgeon to accept. In addition, it is very delightful if useful data can be obtained with a low X-ray exposure based on the treatment method. The same is true in the dental field. In the field of dentistry, one of such treatments is intraoral radiography. In this method, an X-ray image is obtained by irradiating an X-ray film fixed to a portion of a tooth to be photographed on a dentition in the oral cavity with a finger or an instrument. While a precise image in the range of 3-4 teeth can be obtained, since the film is placed in the oral cavity, the patient's pain is not small.

In order to perform this photographing more precisely, it was difficult in the case of the devices described in the various references mentioned above. The reason is that it is difficult to control the position and posture of the X-ray tube and the detector in order to make the beam-shaped X-ray incident on the target tooth at a desired angle and accurately receive the transmitted X-ray.

The present invention has been made in view of the above circumstances, and provides an X-ray imaging apparatus with low X-ray exposure that can increase the degree of freedom in setting a focal plane in an imaging space, that is, setting an X-ray path trajectory. Its main purpose is to do. In addition, X-ray imaging with low X-ray exposure, with the ability to increase the degree of freedom of setting a partial focal plane and X-ray path in the imaging space, and accurately teaching the desired precision imaging range Another object is to provide a device. In addition, another object is to provide an X-ray imaging apparatus with low X-ray exposure that is easy to convey and easy to position, and can increase the degree of freedom in setting a focal plane in the imaging space.

In order to achieve the main object described above, an X-ray imaging apparatus according to one aspect of the present disclosure has an X-ray tube having a point-like focal point and irradiating X-rays having a spread from the focal point, A detector that detects the X-rays emitted from the X-ray tube and outputs data corresponding to the amount of the X-rays, and passes the X-ray tube and the detector through a predetermined center of rotation. It is configured to be rotatable around a central axis. The apparatus is configured such that the X-ray tube receives the X-ray so that the X-ray tube is accommodated, and the tube accommodating portion is rotatable around a first axis parallel to the central axis. An X-ray tube arm having a tube support portion to support, a first driving means for rotating the tube housing portion around the first axis with respect to the tube support portion, and the X-ray incident thereon A detector including a detector accommodating portion that accommodates the detector and a detector supporting portion that rotatably supports the detector accommodating portion around a second axis parallel to the central axis. An arm, second driving means for rotating the detector accommodating portion around the second axis with respect to the detector support portion, and the X-ray tube arm and the detector arm independently of each other. Third driving means that supports the same axis so as to be drivable and drives both arms to rotate around the central axis. The first and second in accordance with a speed pattern in which the X-ray tube arm, the detector arm, the tube housing portion, and the detector housing portion are rotated independently of each other for scanning by the X-ray. And control means for controlling the third drive means.

Particularly preferably, the first distance from the central axis to the first axis is set to a value larger than the second distance from the central axis to the second axis, and the X-ray tube And the detector can be rotated along different circular orbits.

According to this configuration, the X-ray tube and the detector are rotated independently of each other around the same central axis passing through one rotation center. In addition, the X-ray tube and the detector can be rotated around first and second axes parallel to the rotational axis at their respective rotational positions. That is, since both the X-ray tube and the detector can rotate (attitude control), the two can always be kept facing each other. As a result, while the X-ray tube and the detector rotate on their respective circular orbits, the configuration is relatively simple and can be miniaturized. The X-ray path can be easily changed, so that the imaging space can be drawn from various angles. For this reason, various focal planes can be set in the imaging space.

Further preferably, the imaging is performed by irradiating the imaging part of the subject located in the imaging space between the tube housing part and the detector housing part with a laser beam simulating the actual irradiation of the X-ray. Teaching means capable of instructing a partial imaging range of a part before imaging; setting means for decoding the partial imaging range instructed by the teaching means and setting the speed pattern according to the decoding result; ,
Is provided.

According to the configuration according to this other aspect, an X having a function of increasing the degree of freedom in setting a partial focal plane in an imaging space and setting an X-ray path and teaching a desired precision imaging range accurately. A line imaging apparatus can be provided.

Further, preferably, the imaging space that holds the X-ray tube arm and the detector arm rotatably and allows the X-ray tube arm and the detector arm to rotate around the specific part. An elevator for providing the pedestal, and a pedestal portion equipped with the elevator,
And a shielding body that is located so as to define the imaging space and is formed of a shielding material that shields the X-ray.

In another preferred example, the X-ray imaging apparatus moves to the back of the dental treatment chair, is positioned on the rear side of the dental treatment chair, and lies on the back of the dental treatment chair. An apparatus for performing X-ray imaging by positioning a head in an imaging space between the X-ray tube and the detector, an operation unit operated by an operator, and transmission for transmitting an operation given to the operation unit Means, a position specifying means for specifying a predetermined position when the X-ray imaging apparatus is laid on the chair, and the X-ray imaging by being locked to the position specifying means according to the operation transmitted by the transmitting means. Fixing means for fixing the device in the predetermined position.

In the accompanying drawings,
FIG. 1 is a perspective view showing a front side of an X-ray panoramic imaging apparatus as an X-ray imaging apparatus according to the first embodiment of the present invention. FIG. 2 is a perspective view showing the back of the X-ray panoramic imaging apparatus as the X-ray imaging apparatus according to the first embodiment. FIG. 3 is a perspective view for explaining the positional relationship between the X-ray panoramic imaging apparatus and the dental treatment chair and the position of the subject at the time of imaging. FIG. 4 is a partial cross-sectional view illustrating a scattered radiation shielding plate built in the bottom surface. FIG. 5 is a perspective view for explaining the scattered radiation shielding cover. FIG. 6 is a diagram illustrating a four-surface shielding structure including a scattered radiation shielding cover that covers the upper surface and both side surfaces and a scattered radiation shielding plate that covers the bottom surface portion. FIG. 7 is a side view for explaining the 4-axis independent drive of the X-ray panoramic imaging apparatus. FIG. 8 is a front view for explaining the 4-axis independent drive of the X-ray panoramic imaging apparatus. FIG. 9 is a block diagram showing a part of the electrical configuration of the X-ray panoramic imaging apparatus. FIG. 10 is a diagram illustrating the relationship between a standard dentition, a 3D reference tomographic plane, and an X-ray path. FIG. 11 is a graph illustrating a speed pattern instructing partial revolutions of the X-ray tube and the detector related to two axes in the four-axis independent control. FIG. 12 is a graph illustrating a speed pattern instructing partial revolutions of the X-ray tube and the detector relating to the remaining two axes of the four-axis independent control. FIG. 13 is a flowchart illustrating a procedure for panoramic shooting. FIG. 14 is a diagram for explaining a typical rotational position of the X-ray tube and the detector during panoramic imaging and a state of positioning by a laser beam. FIG. 15 is a perspective view of the internal structure of the apparatus main body mounted on the X-ray panoramic imaging apparatus according to the first modification as seen from the front. FIG. 15 is a perspective view of the internal structure of the apparatus main body according to the first modification when viewed from the rear. FIG. 17 is a perspective view illustrating a scattered radiation shielding cover according to the second modification. It is a figure explaining the conventional dental X-ray used in order to explain the X-ray panoramic imaging device concerning the 2nd embodiment of the present invention. FIG. 19 is a diagram for explaining teaching employed in the second embodiment. FIG. 20 is a diagram illustrating a configuration corresponding to the teaching device according to the second embodiment. FIG. 21 is a diagram for explaining teaching. FIG. 22 is a diagram for explaining teaching processing. FIG. 23 is a diagram for explaining calculation of control data in teaching. FIG. 24 is a flowchart for explaining the procedure of the partial shooting operation. FIG. 25 is a graph illustrating a speed pattern of a target tooth related to partial imaging when it is assumed that there is a dentition along a standard trajectory. FIG. 26 is a side view for explaining the position of the scattered radiation shielding plate provided on the back surface of the X-ray panoramic imaging apparatus according to the third embodiment of the present invention. FIG. 27 is a diagram for explaining the attachment of an X-ray protective curtain that can be used in the third embodiment and that is detachably disposed on the front side during imaging. FIG. 28 is a diagram illustrating a six-side shielding structure when the scattered radiation shielding means shown in both FIG. 26 and FIG. 27 is employed. FIG. 29 is a side view showing an X-ray panoramic imaging apparatus and a floor fixing unit according to the fourth embodiment of the present invention. FIG. 30 is a perspective view showing an X-ray panoramic imaging apparatus and a floor fixing unit according to the fourth embodiment. FIG. 31 is a front view and a side view of the operation lever. FIG. 32 is a schematic view taken along the line IX-IX in FIG. 32 for explaining the outline and operation of the link mechanism from the operation lever to the positioning pin together with the positioning operation of the positioning pin. FIG. 33 is a diagram for explaining an outline of a cross-sectional structure taken along lines II and II-II in FIG. FIG. 34 is a diagram for explaining the structure of the positioning pin and the vertical movement operation. FIG. 35 is a perspective view of the floor fixing portion. FIG. 36 is a cross-sectional view along a direction orthogonal to the longitudinal direction of the floor fixing portion. FIG. 37 is a block diagram showing the connection of sensors, LEDs, and processors for detecting the vertical movement of the positioning pins. FIG. 38 is a diagram for explaining a modification of the position detection means of the floor fixing portion for positioning. FIG. 39 is a diagram for explaining another modified example of the position detecting means of the floor fixing portion for positioning.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[First embodiment]
An embodiment of an X-ray panoramic imaging apparatus as an X-ray imaging apparatus according to the present invention will be described with reference to FIGS.

The panoramic imaging apparatus 1 is configured as a dental diagnostic apparatus that captures a panoramic image of a subject's jaw (including a dentition).
The panoramic imaging apparatus 1 teaches the apparatus 1 itself the angle and range of X-ray irradiation for performing the precision imaging, and reflects the taught angle and range. The teaching device for setting the control data is functionally integrated.

According to this panoramic imaging apparatus 1, a pseudo three-dimensional tomographic image of the subject's jaw (the image itself is a two-dimensional image, but three-dimensionally according to the shape of an imaging region such as a dentition). The displayed cross-sectional image) can be taken. Moreover, according to this apparatus 1, the precision imaging | photography which image | photographs the partial area | region of the dentition of a jaw part more precisely can also be performed.
In the case of this panoramic photographing apparatus 1, the control of the rotational operation for precision photographing is based on an original control method called “4-axis independent control”. The “4-axis independent control” employs a unique anti-scattering structure because the apparatus is portable and can be used on the side of the dental treatment chair 2. For this reason, first, the configuration of the entire apparatus including the scattered radiation prevention structure will be described, followed by the description of the configuration of the 4-axis independent control, and then the configuration of the teaching device for precision imaging.

In this embodiment, the X-ray imaging apparatus according to the present invention is configured as a panoramic imaging apparatus, but the X-ray imaging apparatus is not necessarily limited to the dental field. This X-ray imaging apparatus may be configured to image various other parts such as otolaryngology imaging and bone / joint parts of limbs. Furthermore, this X-ray imaging apparatus may be implemented as an X-ray CT apparatus.

FIG. 1 and FIG. 2 show the appearance of the dental X-ray panoramic imaging apparatus 1 according to this embodiment from the front side and from the back side. FIG. 3 shows a state in which the panoramic photographing apparatus 1 is used while being positioned on the side of the dental treatment chair 2.

As can be seen from FIGS. 1 and 2, the panoramic photographing apparatus 1 includes a pedestal portion 12 on which four casters 11 (moving means) are mounted, a power supply box 13 mounted on the pedestal portion 12, and a pedestal portion 12. And a console 15 equipped with a computer for controlling and image processing. The console 15 is connected to the main body BD of the apparatus 1 via a cable or via wireless communication. Here, the main body BD means an apparatus portion excluding the console 15 and a floor fixing portion 53 (see FIG. 3) described later.
[Overview of overall system configuration]
First, an outline of the overall mechanical configuration of the panorama photographing apparatus 1 will be described.

The casters 11 are provided at the four corners of the lower surface of the base 12. For this reason, the dentist or the operator can move by pushing the panoramic imaging apparatus 1 and can freely move from room to room or between the room place and the side of the dental treatment chair 2. . The caster 11 can be locked and unlocked by depressing or raising a pedal 11P (see FIG. 2).

The elevator 14 includes an elevating mechanism (not shown) in its interior, and is electrically driven with respect to the pedestal portion 12 (that is, the floor surface, that is, the dental treatment chair 2) in an arbitrary range of height (eg, 10 to 15 cm). It is configured to be movable up and down at a height position. The power supply box 13 includes a power supply circuit that supplies necessary power to each part of the system. The elevator 14 provides an imaging space S having a substantially rectangular parallelepiped shape for performing X-ray scanning with the head H of the patient P positioned as shown in FIG.

XYZ orthogonal coordinates as shown in the figure can be set if the vertical movement direction of the elevator 14 is the Y axis. Since the head H of the patient P is positioned in the imaging space (object space) S as shown in FIG. 3 at the time of X-ray imaging, the direction of the Z axis is the direction from the top of the head H toward the toes (median) Line direction). For this reason, the direction of the Z axis coincides with the body axis direction. Furthermore, since the direction of the Z axis is also the front-rear direction of the device 1, it can also be called the front-rear direction. In the present embodiment, the side where the head H of the subject P is put into the imaging space S of the panoramic imaging apparatus 1 is referred to as the front surface (front surface), and the opposite surface is referred to as the rear surface (back surface).

The elevator 14 includes a bottom surface portion 14A located on the lower side thereof and a back surface portion 14B located on the bottom surface portion 14A in contact with the bottom surface portion 14A on the back surface side in the X-axis direction. Further, the elevator 14 further includes a scattered radiation shielding cover (part of the shielding body) which overlaps and overlaps both sides of the bottom surface portion 14A, that is, both sides in the X-axis direction and can be manually slid in the front-rear direction. ) 14C. The scattered radiation shielding cover 14C is supported by rails RL provided on both lateral sides of the bottom surface portion 14A, and is slidably engaged in the front-rear direction. In order to perform this slide manually, a handle 16 is attached to the upper side and the rear side of the scattered radiation shielding cover 14C.

As will be described later, the scattered radiation shielding cover 14C serves as a first shielding body that shields scattered radiation of X-rays.

The bottom surface portion 14A is formed of a member formed by folding a rectangular resin or metal plate and joining both ends thereof to have a certain height and bend toward the outside in the height direction, that is, the Y-axis direction. The The inside of this bending member is hollow. The reason for this curvature is that the imaging space S is secured as wide as possible and the design is taken into consideration.

As shown in FIG. 4, a scattered radiation shielding plate (second shielding member) 20 made of a lead plate is attached to the upper side of the cavity inside the bottom surface portion 14A. A part of the edge in the horizontal direction (X-axis direction) of the scattered radiation shielding plate 20 is folded along the folding of the bottom surface portion 14A in the height direction (Y-axis direction). The lead plate has a thickness of 0.3 mm and functions as a second shielding body that shields scattered X-ray rays.

A mechanism part including a drive system including a motor, a power transmission mechanism, and the like and an encoder (rotational position sensor) for monitoring the operation of the drive system is built in the back surface portion 14B of the elevator 14. As this mechanism portion, two arms 21 and 22 coupled to two electric motors that can rotate independently of each other project from the back surface portion 14B into the imaging space S. These arms 21 and 22 have an L-shaped X-ray tube arm 21 with an X-ray tube 23 for irradiating fan-shaped X-rays at the tip side and a detector 24 for detecting X-rays at the tip side. L-shaped detector arm 22. The other ends of the arms 21 and 22 are coaxially linked around the rotation center O and can rotate independently of each other (see arrows T and D in FIG. 1). Are combined separately. The motor is, for example, a stepping motor, and its rotational position is detected by an encoder (not shown). Note that a virtual straight line passing through the rotation center O and parallel to the Z axis is referred to as a central axis CA. The central axis CA is an axis that can also be called the rotation center axis of the arm, and is physically different from the rotation center O of the arm, but is present at the same position when observing along the Z-axis direction. .

Further, each of the X-ray tube arm 21 and the detector arm 22 supports only the tip side portion, that is, the portion containing the X-ray tube 23 and the detector 24 on the support side, that is, the back surface portion 14B. The support portion can be independently rotated within a predetermined angle range with respect to the support portion side. Arrows T1 and D1 in FIG. 1 indicate this rotation. That is, the X-ray tube 23 and the detector 24 have a total of four degrees of freedom of independent rotation with respect to the back surface portion 14B.

The X-ray tube 23 incorporates a collimator (not shown). This collimator collimates the X-rays irradiated by the X-ray tube 23 according to the shape of the X-ray incident window WD of the detector 24. The X-ray incident window WD has an elongated two-dimensional opening. For this reason, the X-rays irradiated from the X-ray tube 23 are narrowed down to a fan beam XB having a rectangular cross section in accordance with the size of the X-ray incident window WD.

As will be described later, the detector 24 has a structure in which a plurality of modules in which semiconductor elements that directly convert X-rays into electrical signals are arranged in two-dimensional pixels are arranged in a plurality of columns.

At the time of imaging, the head H of the subject P is located in the imaging space S as will be described later. At this time, the X-ray tube 23 and the detector 24 are positioned substantially opposite to each other across the jaw. When the apparatus is activated, the X-ray tube 23 and the detector 24 rotate independently of each other over the head H over an angle range of, for example, 220 ° (see the arrow in FIG. 3). X-rays are emitted from the tube 23 continuously or in pulses. For this reason, the X-ray XB irradiated from the X-ray tube 23 passes through the jaw of the head H and is detected by the detector 24. The electric signal output from the detector 24 is sent as frame data to the image processor of the console 15 at a constant rate. The image processor performs a shift-and-add process based on the tomosynthesis method on the frame data, and reconstructs a panoramic image along a cross section in which, for example, the dentition of the jaw is curved along the dentition surface.

As shown in FIGS. 1 and 3, in the imaging space S, one rotation center O is set when viewed from the Z-axis direction. At the position of the rotation center O, an L-shaped teaching arm 25 is provided coaxially with the rotation shaft on the apparatus main body side of the arms 21 and 22. The teaching arm 25 is used for designating a range of a part (target tooth) of a dentition that the dentist wants to examine particularly precisely. In other words, it has a position designation function that is performed in so-called partial photographing or precision photographing, which is performed in the photographing by the conventional intraoral photographing method. A laser beam can be irradiated from the tip of the teaching arm 25. Therefore, the dentist visually confirms the position where the laser beam hits the dentition while holding the tip of the teaching arm 25 and manually rotating the arm around the jaw. Through this visual confirmation work, the angle position of the target tooth in the circumferential direction and the angle of the X-ray that passes through the target tooth when X-ray imaging is actually performed can be verified in advance. The teaching arm 25 is provided with an encoder and a switch (not shown). For this reason, when the angle position and the angle of the transmitted X-ray are determined, the dentist can store the setting information by pressing the switch. This stored information is used by the control unit of the console 15 at the time of actual imaging, and the X-ray irradiation operation and the rotation operation of the X-ray tube 23 and the detector 24 are controlled according to the information.

Of course, in the present embodiment, a configuration in which this partial photographing (precision photographing) is not performed can be adopted. That is, in that case, the teaching arm 25, a mechanism for driving the teaching arm, and software for partial photographing are not required, so that the configuration can be simplified and the calculation amount can be reduced accordingly.

On the other hand, the scattered radiation shielding cover 14C is responsible for defining the upper surface and the left and right side surfaces of the imaging space S and shielding X-rays as shown in FIG. For this reason, the scattered radiation shielding cover 14 </ b> C has a shape obtained by bending a plate having an X-ray shielding function with a constant width into a generally inverted U shape. In other words, the scattered radiation shielding cover 14C has a flat upper surface portion (ceiling body) 14U and both side surface portions (wall bodies) 14L and 14R that are curved and integrally formed from the upper surface portion 14U.

Furthermore, although the scattered radiation shielding cover 14C has an X-ray shielding function as a whole, the scattered radiation shielding cover 14C is formed by combining two kinds of members relating to light transmittance. Specifically, the scattered radiation shielding cover 14C includes a translucent portion 14TR having translucency and a non-translucent portion having non-translucency integrally coupled to the translucent portion 14TR. 14NT. Both the translucent portion 14TR and the non-translucent portion 14NT partially cover the upper surface portion 14U and the side surface portions 14L and 14R.

The non-translucent portion 14NT is formed in an inverted L shape when viewed from the side so as to cover a part of the rear surface side and extend to the bottom surface side across the upper surface portion 14U and both side surface portions 14L, 14R. ing. This non-translucent portion 14NT is formed as a laminated body in which, for example, a lead plate having a thickness of 0.3 mm is sandwiched between resin or metal plates.

On the other hand, the translucent portion 14TR is generally formed in an inverted U shape so as to cover the front side of the non-translucent portion 14NT across the upper surface portion 14U and the side surface portions 14L, 14R. In particular, since the height of the left and right sides of the light-transmitting portion 14TR is shorter than that of the non-light-transmitting portion 14NT, the bottom end of the light-transmitting portion 14TR is supported by the non-light-transmitting portion 14NT. It is like that.

In the present embodiment, the translucent portion 14TR is formed of a transparent acrylic resin having a thickness of 8.5 mm containing a lead component, and thereby has an X-ray shielding ability of a lead equivalent of 0.3 mmPb. Therefore, the translucent portion 14TR has an X-ray shielding function, but also has light transparency. Although the acrylic resin itself is transparent, it contains a lead component, so it actually has a yellowish color but is translucent. For this reason, as will be described later, when the head H of the patient P enters the imaging space S, the patient can see the outside of the cover. Of course, the operator can also visually observe the inside of the imaging space S.

The end portion of the lead-containing acrylic resin forming the light transmitting portion 14TR is inserted into the end portion of the non-light transmitting portion 14NT. For this reason, this acrylic resin and the lead plate sandwiched by the non-translucent portion 14NT are connected to each other without a gap. Therefore, the X-ray shielding function on the upper surface and both sides of the imaging space S is ensured in both the translucent portion 14TR and the non-translucent portion 14NT, that is, the scattered radiation shielding cover 14C. In the present embodiment, an X-ray shielding device is configured by the scattered radiation shielding cover 14C and the scattered radiation shielding plate 20 on the bottom surface portion 14C.

If the view of the scattered radiation shielding cover 14C is changed, it can be said that the entire portion has the function of shielding the scattered radiation, while the part of the scattered radiation shielding portion 14TR has light transmittance.

As a result, as shown in FIG. 6, the X-ray shielding function is given to the top surface, both side surfaces, and the bottom surface that define the imaging space S.

Note that, as shown in FIGS. 1 and 3, a cover portion 51 containing a fixing pin 50 is provided at the front end of the pedestal portion 12. The pin 50 moves up and down in conjunction with an operation lever 52 (see FIG. 2) provided on the upper edge of the back surface part 14 via a wire mechanism (not shown). On the other hand, a floor fixing portion 53 having a substantially triangular shape in a side view and having a hole into which the pin 50 can be inserted is fixed at a predetermined position on the rear surface of the dental treatment chair 2. . For this reason, the pin 50 can be pushed down by moving the apparatus main body BD and operating the operation lever 52 in a state where the tip end position thereof is aligned with the floor fixing portion 53. When the pin 50 enters the hole of the floor fixing portion 53, the apparatus main body BD is positioned with respect to the dental treatment chair 2 (see FIG. 3).

Furthermore, when the apparatus main body BD is moved to another location, the pin 50 is pulled up and released from the floor fixing portion 53 by operating the operation lever 52. Thereby, apparatus main body BD can be moved to another place.

In order to move the apparatus main body BD, a moving handle 54 is fixedly provided on both sides of the operation lever 52 at the upper end of the back surface portion 14B. Therefore, the operator can easily move the apparatus main body BD along with the free rotation of the caster 11 by holding the moving handle 54. The position and shape of the moving handle 54 are not limited to the position and structure tightened in FIG. 2, and if the operator can manually push or move the apparatus main body BD, the number and the shape are included. Can be freely deformed. For example, the moving handle 54 may be formed as an L-shaped handle that is fixed to both corners of the upper end portion of the back surface portion 14B and has a horizontal portion and a vertical portion integrally.

The back surface portion 14B is provided with an irradiation switch 56 for commanding X-ray irradiation and rotation of the X-ray tube / detector via a cord 55 having a length of 2 m, for example. This irradiation switch 56 is configured as a deadman switch. That is, X-ray irradiation is performed only while the push button of the irradiation switch 56 is being pressed. The switch signal of the irradiation switch 56 is sent to the console 15.

Based on the above configuration, a portable panoramic photographing apparatus 1 having a height of about 100 to 115 cm, a width of about 80 to 95 cm, and a depth of about 75 to 90 cm is provided. In addition, since the X-ray shielding function is given to the four surfaces of the upper surface, both side surfaces, and the bottom surface that define the imaging space S, the imaging space S is regarded as a substantial X-ray shielding room. You can also Therefore, in this embodiment, the X-ray shielding chamber (that is, the device 1) can be easily carried to an arbitrary place by the caster 11 by grasping and pushing the moving handle 54 and can be used there. .

[Configuration and control of 4-axis independent drive of imaging system]
Here, with reference to FIGS. 7 to 12, the configuration and control for the 4-axis independent drive of the imaging system including the X-ray tube 23 and the detector 24 will be further described.

As described above, the panoramic imaging apparatus 1 includes the X-ray tube arm 21 and the detector arm 22 that extend in the lateral direction from the elevator section of the elevator 14. As shown in FIG. 7, the two arms 21 and 22 are both formed in an approximately L shape, and the ends of the support portions (tube support portions and detector support portions) 21L and 22L of the arms 21 and 22 respectively. The parts are superposed so as to overlap each other and are attached to the elevator 14. The elevator 14 is equipped with a rotary drive mechanism 83 that can rotate the two arms 21 and 22 independently of each other, that is, at different speeds. The above-described X-ray tube 23 and detector 24 are mounted on the opposing arm portions 21A and 22A on the distal ends of the two arms 21 and 22, respectively. On the front surface of the X-ray tube 23 on the X-ray irradiation side, a slit (diaphragm) 84 for forming X-rays into a fan shape is disposed. The opening area of the slit 84 is variable, and the size of the opening area is controlled by an opening driving unit 85 such as a motor described later. The rotation drive mechanism 83 and the arms 21 and 22 constitute support means for supporting the X-ray tube 23 and the detector 24 so that they can be driven independently of each other.

The X-ray tube 23 is configured as a rotary anode type X-ray tube used for an appropriate anode material such as tungsten. The X-ray tube 23 has a point-like tube focus (X-ray focus) (for example, a diameter of 0.1 mm to 0.5 mm: 0.15 mm in this embodiment) FP. The X-ray tube 23 irradiates X-rays in response to driving power supplied from a high voltage generator described later. The X-rays irradiated from the X-ray tube 23 are narrowed by the slit 84 and formed into a fan-shaped X-ray beam. The X-ray beam then passes through the jaw JW of the subject P and attenuates, and transmitted X-rays reflecting the attenuated state enter the detector 24.

During imaging, as shown in FIG. 8, the jaw JW of the subject P is positioned at a predetermined position in the three-dimensional imaging space S defined between the X-ray tube 23 and the detector 24. For this reason, the X-ray tube 23 and the detector 24 face each other (face to face) with the jaw portion interposed therebetween. The irradiated X-ray beam passes through the slit 84 and then passes through the jaw portion JW (dentition etc.) and is detected by the detector 24. At the time of photographing, the two arms 21 and 22 are independently rotated by the rotation driving mechanism 83.

When viewed from the Z-axis direction, that is, the front-rear direction, the X-ray tube 23 and the detector 24 have a circular trajectory Tx centered on a central axis CA (rotation center O) determined in advance on the system side as shown in FIG. , Td, respectively. The radii Dx and Dd from the central axis CA to the circular trajectories Tx and Td are set to different values in consideration of X-ray exposure, detection accuracy, downsizing of the apparatus, mechanical interference with the patient, and the like. Yes. In the present embodiment, Dx ≠ Dd, and particularly Dx> Dd. The reason why the distance (radius Dd) from the central axis CA to the detector 24 is smaller than that (radius Dx) from the central axis CA to the X-ray tube 23 is that the position of the detector 24 is as much as possible and the jaw JW This is to reduce the attenuation of the incident intensity of X-rays. The distance (radius Dx) from the central axis CA to the X-ray tube 23 is set to a value that can ensure the distance between the X-ray tube and the skin defined by the standard. As a result, the X-ray tube 23 and the detector 24 rotate around the jaw portion along predetermined circular trajectories Tx and Td around the central axis CA. During the rotation, irradiation and detection of the X-ray beam are executed at predetermined intervals.

Therefore, the X-ray tube 23 and the detector 24 are always opposed to each other (facing each other), and X-ray irradiation and detection along a plurality of predetermined desired X-ray paths with respect to the jaw JW (dentition) are performed. In order to perform the above, the X-ray tube 23 and the detector 24 are driven independently of each other at different angular velocities.

Note that “opposing each other” described above is irradiated from the dotted tube focal point (focal position) FP of the X-ray tube 23 when viewed along the Z-axis direction, as shown in FIG. This refers to a state in which the irradiation range of the X-ray beam formed in a cone shape matches the X-ray detection surface 24A of the detector 24. In particular, the center line T in the direction along the XY plane of the X-ray beam intersects the detection center position C in the width direction of the X-ray detection surface (the width in the direction along the XY plane) at 90 °. This is referred to as a “facing state” (see FIG. 8). In FIG. 8, a linear position extending in the X-axis direction from the mechanical rotation center O is defined as a rotation angle θ = 0, and ± rotation directions are set clockwise and counterclockwise from this rotation position.

For this reason, in order to realize the above-mentioned “always facing each other (or facing each other)”, among the arms 21 and 22, the facing arm portion (tube housing portion, detection) housing the X-ray tube 23 and the detector 24. The container housing portions 21A and 22A are independent from each other about the first axis (that is, the X-ray tube swing rotation central axis) AXs and the second axis (that is, the detector swing rotation central axis) AXd. Thus, rotation (spinning, that is, posture) is possible (see FIGS. 7 and 8). For this purpose, rotational drive mechanisms 21B and 22B such as motors are provided on the arms 21 and 22, respectively (see FIG. 7). The drive control of the rotation drive mechanisms 21B and 22B is executed by a controller provided in the power supply box 13 in accordance with a command from the console 15 described later.

In this embodiment, the circular trajectories Tx and Td shown in FIG. 8 indicate the trajectories of the first and second axes AXs and AXd described above when viewed on the XY plane, respectively. In the present embodiment, biaxial rotational degrees of freedom are given to the arms 2 and 22 that are driven to rotate independently of each other by the rotary drive mechanism 83 described above, so that the X-ray tube 23 rotates (so-called swinging rotation) and is detected. Two-axis rotational freedom is given to the rotation (so-called swinging rotation) of the device 24. This gives a total of four axes of rotational freedom.

The detector 24 has a plurality of detection modules in which X-ray imaging elements are two-dimensionally arranged. The plurality of detection modules are formed as blocks independent from each other, and are mounted on the substrate in a predetermined rectangular shape to form the entire detector 24.

The structure of the detector 24 and the processing of the detection signal by the sub-pixel method are known from, for example, International Publication WO 2012 / 0886648A1.

Each detection module is made of a semiconductor material that converts X-rays directly into electrical pulse signals. For this reason, the detector 24 is a photon counting X-ray detector of a direct conversion method using a semiconductor.

The number of pixels each detection module is 40 × 40 pixels, for example, the size of each pixel _{S n} is 200 [mu] m × 200 [mu] m, for example. This pixel size is set to a value that allows detection of incident X-rays as a collection of many photons. Each pixel responds to the incidence of each photon of the X-ray and outputs an electric pulse having an amplitude corresponding to the energy of each photon. That is, each pixel can directly convert X-rays incident on the pixel into an electrical signal.

For this reason, the detector 24 counts the incident X-ray photons for each pixel constituting the detection surface of the detector 24, and outputs the electric quantity data reflecting the counted value, for example, a high frame of 300 fps. Output at the rate. This data is also called frame data.

As the semiconductor material of the semiconductor layer, that is, the semiconductor cell, cadmium telluride semiconductor (CdTe semiconductor), cadmium zinc telluride semiconductor (CdZnTe semiconductor (CZT semiconductor)), silicon semiconductor (Si semiconductor), thallium bromide (T1Br), Mercury iodide (HgI ₂ ) or the like is used. Note that a detector having a combination structure of a photodiode and a scintillator may be used instead of the detector using the semiconductor cell.

On the other hand, in this panoramic photographing apparatus 1, the four laser beams are used as positioning means. Specifically, a midline laser 211 provided on the upper side of the imaging space S side of the back surface portion 14B, a horizontal laser 212 provided at each predetermined position on the side surface of the opposing arm portion 22B of the detector arm 22, and an occlusal plane laser 213 and the canine laser 214 (see FIG. 7). These lasers 211 to 214 project a linear laser marker onto the head of the subject P during positioning, and their drive is controlled via the console 15. The median laser 211 aligns the midline of the head H of the subject P, the horizontal laser 212 aligns the Frankfurt plane, the occlusal plane laser 213 aligns the occlusal plane, and the canine laser 214 aligns the canines in the dentition. (See FIG. 14, (B ′)).

Furthermore, shock sensors 215 and 216 for detecting an impact are installed on the opposing arm portions 21B and 22B of the X-ray tube arm 21 and the detector arm 22 as fail-safe sensors, respectively (see FIG. 7). This is because, for example, when something hits the arms 21 and 22, it senses that and stops scanning, and the output signals of the shock sensors 215 and 216 are also sent to the console 15.

As shown in FIG. 9, the console 15 includes an interface (I / F) 131 that performs input and output of signals, a controller 133 that is communicably connected to the interface 131 via a bus 132, and a first storage unit 134, a data processor (CPU) 135, a display device 136, an input device 137, a calibration calculator 138, a second storage unit 139, first to fourth ROMs 140A to 140D, and a threshold value assigner 140E.

The controller 133 controls the driving of the panorama photographing apparatus 1 in accordance with a program given in advance to the first ROM 140A. For this control, a command value is sent to the high voltage generator 140F that supplies a high voltage to the X-ray tube 23, a command value is sent to the opening drive unit 85 to change the opening area of the slit 84, and calibration is performed. A drive command to the operation calculator 138 is also included. The first storage unit 134 stores frame data and image data that are count values sent from the detector 24 via the interface 131. Further, the controller 133 receives the switch signal of the irradiation switch 56 via the interface 131, and controls scanning as will be described later. Similarly, the controller 133 also receives the signals of the shock sensors 215 and 216 via the interface 131, and controls the continuation / stop of the scan described later. Further, the controller 133 is connected to the positioning lasers 151 to 154 via the interface 131, and is configured to drive the lasers 151 to 154 when a positioning command is issued.

The data processor 135 operates based on a program given in advance to the second ROM 140B under the control of the controller 133. Further, during panoramic shooting, the data processor 135, by its operation, adds to the frame data stored in the first storage unit 134 tomosynthesis based on a known calculation method called shift add add. Implement the law. Thereby, the panoramic image of the tomographic plane with the oral cavity of the subject P is obtained. The display device 136 is responsible for displaying images to be created, information indicating the operation status of the apparatus, and operator operation information provided via the input device 137. The input device 137 is used by an operator to give information necessary for imaging to the apparatus.

In addition, the calibration calculator 138 operates under the control of the controller 133 under a program built in the third ROM 140C in advance, and is given to each energy discrimination circuit for each pixel in the data counting circuit. Calibrate digital quantity thresholds for energy discrimination.

Under the control of the controller 133, the threshold value assigner 140E calls the digital amount threshold value stored in the second storage unit 139 for each pixel and for each discrimination circuit at the time of imaging, and uses the threshold value as a command value as an interface. The signal is transmitted to the photon counting circuit of the detector 24 via 131. In order to execute this process, the threshold value assigner 140E executes a program stored in advance in the fourth ROM 140D.

The controller 133, the data processor 135, the calibration calculator 138, and the threshold value assigner 140E all include a CPU (central processing unit) that operates according to a given program. These programs are stored in advance in the first to fourth ROMs 140A to 140D, respectively.

In this embodiment, as known from International Publication No. WO2011 / 142343 (International Application No. PCT / JP2011 / 060731), the structure of the imaging space S is analyzed using a phantom, and the collection channel of the detector 24 is calibrated. Is done. This calibration is executed at an appropriate timing such as before imaging or during maintenance inspection.

FIG. 10 shows a standard dentition TR, a trajectory SS (referred to as a standard trajectory) of projection of the horseshoe-shaped 3D reference tomographic plane of the dentition TR onto the XY plane, the position of the cervical vertebra CS, and the subject P An X-ray beam path XB at each rotation angle θ in the circumferential direction CR of the jaw JW is illustrated. The path XB indicates a path connecting the X-ray focal point FP of the X-ray tube 23 and the center position C in the horizontal width direction (Y-axis direction) of the detection surface 24A (see FIG. 8) of the detector 24.

As can be seen from FIGS. 7 and 8, the tube focal point FP of the X-ray tube 23 is located on the line of the first axis (that is, the central axis of swinging of the X-ray tube) AXs, and the detection surface of the detector 24 The center position C in the lateral width direction of 24A is located on the line of the second axis (that is, the center axis of rotation rotation of the detector) AXd. This simplifies the geometric positional relationship between the rotation (rotation) of the X-ray tube 23 and the detector 24 and the X-ray path, and makes it easier to design the attitude control of the X-ray tube 23 and the detector 24. Become.

For example, a speed pattern for performing two types of photographing methods (both panoramic photographing) called standard photographing and orthogonal photographing can be set for the locus SS (standard orbit) of the 3D reference tomographic plane. The standard imaging is an imaging method in which X-rays are irradiated so as to avoid the left and right jaw bones as much as possible with respect to the locus SS. The orthogonal imaging is an imaging method in which X-rays are irradiated so that the path is always orthogonal to the locus SS. FIG. 10 schematically shows an X-ray path in a half of the scan range θ = 220 ° in standard imaging (a range of ± 110 ° if the predetermined folding position is θ = 0 °).

Furthermore, even with the same standard imaging, the size of the trajectory SS (standard trajectory) of the 3D reference tomographic plane varies depending on the difference between adults and children. The same applies to orthogonal shooting. For this reason, a plurality of types of velocity patterns for standard imaging and / or orthogonal imaging are preliminarily rotated in a partial range in the circumferential direction around the central axis CA of the X-ray tube 23 (here, partial revolution). , Rotation of a partial range around the axis AXs of the X-ray tube 23 (here, partial rotation), rotation of a partial range in the circumferential direction around the central axis CA of the detector 24 (partial rotation) Revolving) and a partial range of rotation about the axis AXd of the detector 24 (partial rotation).

This speed pattern is obtained by taking the scan time (for example, 12 seconds) on the horizontal axis and the revolution or rotation angle on the vertical axis. In this embodiment, the revolution means that the X-ray tube 23 and the detector 24 rotate or rotate in the circumferential direction along each of the trajectories Tx and Td that are separated from the central axis CA by a predetermined distance. Means that the X-ray tube 23 and the detector 24 themselves rotate or rotate around the respective rotation axes AXs and AXd. Further, “partial” refers to rotating a partial range in the entire circumferential direction, and refers to a partial angular range in the 360 rotation range.

11 and 12 illustrate a speed pattern indicating the revolution and rotation of the X-ray tube 23 and a speed pattern indicating the revolution and rotation of the detector 24 when performing standard imaging and orthogonal imaging. For example, the curves A and B in FIGS. 11 and 12 are for orthogonal imaging for adults of the X-ray tube 23 and the detector 24 in the range of about 220 ° when the circumferential angle θ is set as shown in FIG. The revolving and rotation speed patterns are shown respectively. As can be seen from these speed patterns A and B, the rotation speed is increased in these portions so that the left and right jawbone portions are scanned as roughly as possible, and the speed is set so as to be dense in the dentition TR portion. . Similarly, curves A ′ and B ′ in FIGS. 11 and 12 respectively show the revolution and rotation speed patterns of the X-ray tube 23 and the detector 24 for standard imaging for adults in the range of about 220 °.

Note that the rotation and rotation speed patterns for orthogonal shooting and standard shooting for children use the portion of the horizontal axis 1 to 11 seconds in FIGS. 11 and 12. In other words, although the angular range of revolution and rotation is the same, a standard trajectory for children with a smaller collection range is secured by shortening the collection time. This is based on the statistics that the dentition between the child and the adult grows as the adult grows, but the size of the front teeth does not change much.

Further, curves A and B in FIG. 12 show partial rotations of the X-ray tube 23 and the detector 24, that is, so-called swing patterns within a certain angle. As this constant angle, about ± 15 ° is set. This angle is set to 0 ° when the X-ray tube 23 and the detector 24 face each other. As shown in FIG. 11, the swinging of the X-ray tube 23 and the detector 24 itself is not constant, so the X-ray path XB does not always pass through the central axis CA. There are far more X-ray paths XB with the central axis CA removed. This is to increase the degree of freedom in designing the X-ray path XB as indicated by the arrow YJ in FIG. When the X-ray path XB does not pass through the central axis CA, if nothing is done, the X-ray tube 23 and the detector 24 are deviated from the facing state and the detection sensitivity is lowered. Therefore, when the X-ray path does not pass through the central axis CA, it is necessary to cooperatively swing the X-ray tube 23 and the detector 24 according to the amount of deviation of the X-ray path XB from the central axis CA. is there. Of course, it is possible to swing one of the detectors 24, but in this case, the degree of freedom in setting the X-ray path XB is lowered, so it is better to use both swings together. Such a speed pattern is installed in advance in the apparatus by the manufacturer.

That is, the types of speed patterns prepared in this embodiment are
・ Speed pattern of standard shooting for adults (speed pattern group consisting of curves A ′ and B ′ in FIG. 11 and curves A ′ and B ′ in FIG. 12),
-Speed pattern for orthogonal shooting for adults (speed pattern group consisting of curves A and B in FIG. 11 and curves A and B in FIG. 12),
Speed pattern for standard shooting for children (speed pattern group consisting of time-reduced curves A ′ and B ′ in FIG. 11 and time-reduced curves A ′ and B ′ in FIG. 12),
・ Adult orthogonal shooting speed pattern (speed pattern group consisting of time-reduced curves A and B in FIG. 11 and time-reduced curves A and B in FIG. 12),
It is.

Furthermore, the velocity patterns of the X-ray tube 23 and the detector 24 are not necessarily those for the standard 3D reference tomographic plane as described above. This may be a velocity pattern for an arbitrarily shaped 3D reference tomographic plane. For example, the shape of the projection trajectory (standard trajectory) SS on the XY plane of the 3D reference tomographic plane shown in FIG. 10 described above may be a horseshoe shape in which the vicinity of the front teeth is narrower or wider. Conversely, the back teeth may form a narrower or wider horseshoe shape. It is also possible to set the above four types of velocity patterns for performing standard imaging and / or orthogonal imaging on a 3D reference tomographic plane having such a modified projection locus SS. The velocity pattern related to such a deformed shape can be prepared in advance on the system side, or can be calculated and stored in a computer at a medical site or a research site.

The plurality of speed patterns set with such a high degree of freedom are stored as a table in the first storage unit 134 (storage means: see FIG. 9). For this reason, the controller 133 reads out a desired speed pattern from the first storage unit 134 to the work area through interactive exchange with the operator. When the scan is started, the controller 133 controls the rotation drive mechanisms 83, 21B, and 22B shown in FIG. 9 according to the read speed pattern. As a result, X-rays irradiated from the X-ray tube 23 and incident on the detector 24 through the jaw JW of the subject P are designated by desired standard imaging or orthogonal imaging for each rotation angle θ in the circumferential direction. Pass the path XB. For this reason, the detector 24 always outputs the detected frame data while maintaining a posture facing the X-ray tube 23. This frame data is reconstructed into a panoramic image by the data processor 135.

Next, an example of the procedure of X-ray panoramic imaging by the X-ray panoramic imaging apparatus 1 according to this embodiment will be described with reference to FIG.

When using the X-ray panoramic imaging apparatus 1, first, the apparatus 1 is positioned at a predetermined position on the back side of the dental treatment chair 2 and fixed to the floor surface. At this time, the operation lever 52 described above is operated to push the pin 50 down, and the pin 50 is engaged with the floor fixing portion 53. Thereby, positioning and fixation with respect to the dental treatment chair 2 of the main body BD of the X-ray panoramic imaging apparatus 1 are achieved. This facilitates the positioning of the scan of the X-ray panorama apparatus 1 with respect to the head H of the patient P when the backrest is tilted while sitting on the dental treatment chair 2.

When the positioning of the X-ray panoramic imaging apparatus 1 is finished, the operator (or dentist) turns on the apparatus. As a result, the controller 133 of the console 15 is activated and interactively executes the following processing. First, the controller 133 displays a login screen on the display 136, and thus performs login (FIG. 13, step S1). After this, the controller 133 causes the display 136 to display a panoramic shooting GUI (graphical user interface) (not shown). For this reason, the dentist inputs patient information (imaging date, patient ID, patient name, etc.) from the patient information input screen provided by this GUI (step S2).

Next, in the same manner, a shooting type is selected on the GUI screen of the display 136 (step S3). In this embodiment, one of the four types of shooting, which is set by default, is standard shooting for adults, orthogonal shooting for adults, standard shooting for children, and orthogonal shooting for children. Selected. Of course, if an imaging method having a customized size trajectory is set, it may be selected. In response to this selection, the controller 133 reads a speed pattern for executing the selected imaging method from the table in the first storage unit 134 to the work area. For example, when standard shooting for adults is selected, four types of pattern data of speed patterns A ′ and B ′ illustrated in FIGS. 11 and 12 are read out.

Next, shooting conditions are set (step S4). This setting is to set the tube voltage and tube current. When the shooting type is selected as described above, the controller 133 automatically sets the recommended shooting conditions. It is.

When the imaging conditions are set, the controller 133 displays the screen so that the dentist positions the patient P, and waits during that time (step S5).

Therefore, the dentist causes the patient P and his / her attendant to wear X-ray protective clothing, and causes the patient P to sit on the dental treatment chair 2. Next, the scattered radiation shielding cover 14 </ b> C is manually retracted to the rear side (see an imaginary line “retraction position” in FIG. 3). At this stage, the X-ray tube arm 21 and the detector arm 22 are positioned at the respective standby positions (see FIG. 14A).

Furthermore, with the head H of the patient P attached to the headrest HR of the treatment chair 2, the backrest is tilted and the head H is introduced into the imaging space S. At this time, as described above, the main body BD of the panoramic photographing apparatus 1 and the dental treatment chair 2 are fixed to each other via the floor surface. Therefore, the headrest HR (see FIG. 3) of the dental treatment chair 2 is located at the approximate center of the imaging space S. In other words, the head H of the patient P is also guided to a substantially intermediate portion between the X-ray tube arm 21 and the detector arm 22 waiting in the imaging space S.

When this introduction is completed, the dentist presses the GUI laser irradiation button (not shown) of the display 136 and presses the positioning irradiation button. In response to this, the controller 133 rotates only the detector arm 22 and moves it to a positioning position, that is, a position directly beside the patient's head H (see FIG. 14B). Further, the controller 133 drives the midline laser 211, the horizontal laser 212, the occlusal plane laser 213, and the canine laser 214 (step S6). These four types of laser beams are projected onto the face of the patient P (see FIG. 14B ′).

Next, the GUI of the display 136 instructs the dentist to position the face of the patient P (step S7). First, the dentist adjusts the height of the elevator 14 via the controller 133 so that the linear beam BM1 from the canine laser 214 matches the canine of the patient P. Next, the position of the patient's face is finely adjusted while viewing the beams from the remaining lasers 211 to 213. Specifically, the position of the patient in the body axis direction is adjusted so that the linear beam BM2 from the occlusal plane laser 213 matches the occlusal plane of the patient P. The midline sagittal plane of the head H is aligned with the linear beam BM3 from the midline laser 211. Further, the Frankfurt plane is aligned with the linear beam BM4 emitted from the horizontal laser 212.

After the positioning, the scattered radiation shielding cover 14C is moved to the imaging position in the forward direction (see the solid line “imaging position” in FIG. 3). As a result, as shown by the solid line in FIG. 3, the head H of the subject P is positioned in the defined imaging space S. In order to more reliably perform X-ray shielding, the front surface of the scattered radiation shielding cover 14C may be covered with an X-ray protective cloth containing lead after this positioning. This can be easily performed by detachably attaching a hinge or the like formed on the edge of the upper front surface of the cover 14C.

Therefore, since the GUI of the display 136 displays the completion of preparation, the setup button on the GUI is pressed (step S8). In response to this, the controller 133 rotates the X-ray tube arm 21 and the detector arm 22 to a predetermined setup position (see FIG. 14C). The dentist finally confirms this setup condition. At this time, the state inside the scattered radiation shielding cover 14C, such as the state of the patient P and the arm position, can be confirmed by observing through the window portion by the translucent portion 14TR.

If there is no problem with this confirmation, the dentist performs a scan. This scan is executed when the dentist holds the irradiation switch 56 and presses and keeps pressing the switch 56 from a slightly distant place (step S9). Thereby, as described above, the X-ray tube arm 21 and the detector arm 22 revolve independently of each other along the velocity pattern according to the selected imaging type, and the opposing arm portions 21A, 22A, that is, X The rotational movements of the tube 23 and the detector 24 are controlled independently of each other. That is, the collection of frame data is performed by the scan based on the 4-axis independent control described above. Symbols Ks and Kd in FIG. 14D schematically show the trajectory of the movement of the X-ray tube 23 and the detector 24 due to the revolving motion of the X-ray tube arm 21 and the detector arm 22.

During this scan, the dentist observes the state of the patient while looking inside from the translucent portion 14TR of the scattered radiation shielding cover 14C. Therefore, during the scan, the controller 133 monitors whether the irradiation switch 56 is turned off, that is, whether the dentist feels any inconvenience and releases the push button of the irradiation switch 56 (that is, switch OFF) (step OFF). S10). If there is no abnormality, the determination in step S10 is NO and the scan is continued as it is. However, in the case of YES determination, each drive unit is immediately instructed to stop scanning (step S11). This monitoring is the same for the shock sensor (steps S12 and S11). If there is no abnormality, the dentist continues to press the irradiation switch 56 and the scanning is automatically ended (step S13). That is, the X-ray tube arm 21 and the detector arm 22 scan while moving within the scan range θ (for example, about 220 °) commanded by the operation pattern, and automatically return to the initial retracted position when the scan is completed. (See FIG. 14D).

Thereafter, the scattered radiation shielding cover 14C is retracted rearward to release the patient (step S13).

This completes a series of panoramic shots. The frame data collected by this scan is stored in the first storage unit 134. For this reason, the data processor 135 reconstructs a tomographic image of the dentition TR from this frame data using a predetermined profile curve (a curve defining the amount of overlap between the frame data) for the shift & add process. be able to. Specifically, for this reconstruction, for example, the technique described in US-2012-0230467 A1 can be adopted.

[First modification]
Here, the modification (1st modification) which concerns on embodiment mentioned above is demonstrated with reference to FIG.15 and FIG.16. Here, the same reference numerals are given to components that exhibit the same or equivalent functions as the components of the panoramic photographing apparatus 1 described above, and the description thereof is omitted.

FIGS. 15 and 16 show an example of the internal structure of the main body BD that can be mounted on the panoramic photographing apparatus 1 in place of the drive mechanism described above, and shows a state in which a cover or the like covering the outside is removed. Yes.

In the case of this example, the structure is extremely simplified, and a base part BS that is positioned on the dental treatment chair 2 via the floor surface, and a tower part TW that can be height-adjusted from the base part BS, The driving unit DV provided on the upper portion of the tower unit TW, and the arm unit AM which is attached to the tower unit TW at the upper position and is linked to the driving unit DV.

Among these, the base portion BS has the pedestal portion 12 as in the above-described embodiment, and a telescopic elevator 141 is mounted thereon. The elevator 141 has the function of the elevator 14 described in the above-described embodiment. The elevator 141 is configured such that the outer movable strut 142 can move up and down with respect to the inner fixed strut with a stroke of, for example, 270 mm in the height direction. The elevator 141 incorporates a drive mechanism such as a DC motor and a height sensor.

The movable strut 142 is provided with a drive unit DV having a rotation mechanism similar to the rotation drive mechanism 83 described above. The drive unit DV includes support plates 143 and 144 projecting from both side surfaces of the upper portion of the movable support column 142, and an electric motor 145 with a gear box with electromagnetic brakes disposed on the support plates 143 and 144, respectively. 146. In addition, the drive unit DV includes a rotation drive mechanism 147 provided through the upper part of the movable support column 142 in the front-rear direction (Z-axis direction) orthogonal to the projecting direction of the support plates 143 and 144. The end portion on the front side of the rotation drive mechanism 147 protrudes from the movable column 142, and the support portion 21L of the X-ray tube arm 21 and the support portion 22L of the detector arm 22 described above are provided on the protruding portion. It is attached coaxially. In addition, an end portion on the rear surface side of the rotation drive mechanism 147 also protrudes from the movable column 142, and two speed reducers 148 and 149 are coaxially attached to the protruding portion. Each of the motors 145 and 146 is a stepping motor, and includes gear boxes 145A and 146A on the output shaft side. These gear boxes 145A and 146A are linked to the speed reducers 148 and 149 via belts 150 and 151, respectively. Yes.

For this reason, when the motor 145 for rotating the X-ray tube rotates, the rotational force is decelerated by the gear box 145A and the speed reducer 148 and transmitted to the rotation drive mechanism 147. Similarly, when the detector rotating motor 146 rotates, the rotational force is reduced by the gearbox 146A and the speed reducer 149 and transmitted to the rotation drive mechanism 147. The rotation drive mechanism 147 incorporates a known shaft mechanism that transmits rotation independently from each other inside and outside by a bearing or the like. For this reason, two shafts inside and outside the shaft mechanism are linked to the support portion 21L of the X-ray tube arm 21 and the support portion 22L of the detector arm 22, respectively. Accordingly, the rotation of the X-ray tube rotation motor 145 causes the X-ray tube arm 21 to rotate in the circumferential direction as described above, and the rotation of the detector rotation motor 146 similarly causes the detector arm 22 to move in the circumferential direction. Rotate. Their rotation direction, rotation speed, and rotation range can be controlled independently of each other by controlling the driving of the two motors 145 and 146 separately.

An electric motor 152 with a gear box for rotating the opposing arm portions 21A and 22A at the distal ends of the support portion 21L for the X-ray tube and the support portion 22L for the detector provided as the arm portion AM. , 153 are provided. These electric motors 152 and 153 are stepping motors, and their output shafts are linked to the opposing arm portions 21A and 22A on the X-ray tube side and the detector side, respectively. For this reason, the rotation movements of the electric motors 152 and 153 can control the above-described rotational motions of the opposing arm portions 21A and 22A on the X-ray tube side and the detector side, that is, the X-ray tube 23 and the detector 24, independently of each other. It has become.

As described above, the four-axis rotation operation described above can be independently controlled by the mechanism according to this modification, and the above-described scan control can be performed.

As described above, according to the panoramic imaging apparatus 1 according to the above-described embodiment and the modification thereof, the X-ray tube 23 and the detector 24 are always facing each other while moving independently on different circular orbits. In addition, attitude control of four axes (that is, partial revolution and rotation of the X-ray tube 23 and partial revolution and rotation of the detector 24) is performed. For this reason, the apparatus can be miniaturized and the degree of freedom in designing the X-ray path is extremely high. Moreover, the trajectory of the X-ray path is arbitrarily determined so that a desired image can be taken.

Specifically, the X-ray tube 23 and the detector are arranged around two identical orbits around the same central axis CA passing through one rotation center O and having different distances (diameters) from the central axis CA. 24 are rotated (revolved) independently of each other. In addition, the X-ray tube 23 and the detector 24 are rotated (rotated or swung) around the first and second axes AXs and AXd parallel to the rotation axis CA at the respective rotation positions. it can. That is, since both the X-ray tube 23 and the detector 24 can rotate (attitude control), they can always maintain a state of facing each other. Thus, the X-ray tube 23 and the detector 24 are relatively simple and can be reduced in size by rotating on their respective circular orbits. The fan beam-shaped X-ray path can be drawn from various angles in the imaging space S and can be easily changed. For this reason, various focal planes can be set in the imaging space S.

In addition, the distance from the central axis CA to the X-ray tube 23 and the detector 24 is different. That is, the detector 24 can be rotated at a position as close as possible to the imaging region JW of the subject P. As a result, if the focal spot size (0.15 mm in this embodiment) of the X-ray tube 23 is the same, the magnification rate increases and the resolution increases as the detector 24 approaches the subject P. Detection accuracy is also improved.

As described above, in the panoramic imaging apparatus 1, the X-ray XB irradiated from the X-ray tube 23 is always limited to the size of the X-ray incident window WD of the detector 24. In addition, the X-ray tube 23 and the detector 24 are driven and controlled independently by the four axes, and both are always opposed to each other via the jaw of the subject P during scanning. For this reason, the X-ray XB irradiated from the X-ray tube enters the detector 24. Therefore, the amount of scattered radiation leaking from the imaging space S is small. In particular, since X-rays focused in a fan beam shape having a rectangular opening rotate around the central axis CA, the amount of scattered radiation leaking in the front-rear direction of the imaging space S is further reduced.

In particular, in the case of the panoramic photographing apparatus provided with the rotation drive mechanism described with reference to FIGS. 15 and 16, two electric motors that make a tower portion TW stand up from the base portion BS and perform a revolving motion on the upper portion of the tower portion TW. Motors 145 and 146 were provided. For this reason, compared with the structure which arrange | positions these drive sources in base part BS, the routing of a rotation transmission belt is simplified.

Furthermore, in this modification, a control board (not shown) on which the circuit of the console 15 shown in FIG. 9 is mounted is arranged in the space US on the upper surface of the tower unit TW. For this reason, the power supply box 13 that forms the base portion BS is equipped with only a converter that converts the voltage from AC 100V to DC 24V, and only a cable that sends the DC output to the control board or the electric motor is routed. For this reason, compared with the case where this control board is placed in the power supply box 13, wiring is also simplified.

Furthermore, when the X-ray tube arm 21 and the detector arm 22 are rotated around the central axis CA, no counterweight is provided on the opposite side of these arms, that is, on the back side of the rotation drive mechanism 147. The rotation of these arms 21 and 22 is controlled by precisely controlling along the speed pattern. Usually, when such an arm is rotated so that its rotational radial direction is the height direction, a counterweight is often provided to suppress rotational unevenness due to the gravity. However, since the counterweight is not provided in this modification, the structure is simplified and the weight is reduced accordingly.

[Second modification]
Furthermore, a modified example related to the scattered radiation shielding cover 14C that can be mounted on the panorama photographing apparatus 1 according to the above-described embodiment will be described.

The translucent portion 14TR formed on the cover 14C may be an appropriate rectangular translucent window 14TR ′ provided on both side surfaces as shown in FIG. 17 instead of the shape of FIG. 5 described above. The translucent window 14TR ′ is formed of a resin material containing lead, and the other non-translucent portion 14NT is formed of a metallic plate material. Also by this, the effect of shielding the scattered radiation can be expected, and the entire weight can be reduced by reducing the lead-containing portion.

This translucent window 14TR ′ is primarily capable of observing the state of the patient by the dentist during scanning, and it is better if the discomfort of the patient who is not good at closing can be reduced. For this reason, the shape of the translucent window 14TR ′ is not limited to a rectangle, but may be a slit, a circle, or a triangle. Further, the translucent window 14TR ′ may be provided only on one side surface of the cover 14C. The position in the height direction of the translucent window 14TR ′ is usually set so that a dentist who performs a scanning operation in a standing position can observe the head of the patient inside through the translucent window 14TR ′.

[Second Embodiment]
Next, a second embodiment of an X-ray panoramic imaging apparatus as an X-ray imaging apparatus according to the present invention will be described with reference to FIGS.

In the second embodiment and the subsequent embodiments, the same reference numerals are used for components that have the same or equivalent functions as those of the first embodiment and its modification (first modification) described above. Thus, the description thereof is omitted or simplified.

The X-ray panoramic imaging apparatus according to the second embodiment has a more specific configuration of the teaching function outlined in the first embodiment. In addition to the configuration of the X-ray panorama apparatus according to the first embodiment, this teaching function includes a standard imaging method and an orthogonal imaging method along the standard trajectory SS on the dentition TR that is the trajectory of the 3D reference tomographic plane. In addition to or can be carried out alone.

Therefore, with reference to FIG. 19 to FIG. 24, a teaching device that is functionally integrated with the panoramic photographing apparatus 1 will be described.

First, a conventional imaging method called dental x-ray aimed at by this teaching apparatus will be described with reference to FIG. FIG. 13 shows the geometrical relationship when the film FM is inserted into the subject's mouth and irradiated with X-rays from the outside. Several types of film FM are inserted into the mouth, from those for children of about 22 × 35 mm to those for adults of about 31 × 41 mm. This film FM is placed at a position where the target teeth are photographed, and is photographed in a state where it is held with a finger or the like. In this imaging, the dentist images the X-ray irradiation angle at the time of imaging while adjusting the direction of the cone CN of the external X-ray irradiator. That is, the optimum X-ray incident angle for photographing the target tooth is confirmed in a simulated manner. Of course, the SID (distance between the X-ray focal point and the film) is secured to about 300 to 400 mm.

However, this dental X-ray is a troublesome and time-consuming method for both patients and dentists. The patient needs to press the film FM placed in his / her mouth with his / her finger or the like, and the dentist must adjust the angle of the cone CN while assuming an optimum X-ray irradiation angle. I want to avoid re-taking as much as possible from the viewpoint of X-ray exposure, so it takes time to adjust the angle of the cone CN and the workability is not good, and whether the film photograph taken captures the target teeth optimally I can't understand without seeing.

From such a background, the panoramic imaging apparatus 1 according to the present embodiment intends to achieve this dental X-ray imaging function based on the above-described 4-axis independent control. What is needed at this time is a teaching function.

The precision photographing according to this embodiment will be described with reference to FIG. As shown in the figure, for example, if the second right back tooth is the target tooth, a region 50 mm (25 mm + 25 mm) including this back tooth is the imaging range. Of course, the actual captured image has a rectangular shape of about 50 × 50 mm. Therefore, the detector 24 is located outside the right cheek, and the X-ray tube 23 is located outside the left cheek on the opposite side. Further, since the detector 24 has a small number of pixels in the horizontal width direction and is regarded as a substantially vertical line sensor, the X-ray tube 23 and the detector 24 are simulated while being along the two trajectories Tx and Td. Are translated in opposite directions. Frame data output from the detector 24 during this parallel movement is synthesized by the tomosynthesis method, and a precision photographed image of about 50 × 50 mm is obtained. This partially photographed image replaces an image obtained by a conventional dental X-ray.

At the time of this precision photographing, as shown in FIG. 15, teaching of the optimum X-ray irradiation angle is performed on the target tooth in advance using the teaching arm 25 described above. The dentist can set the X-ray irradiation angle at the time of imaging while simulating the X-ray irradiation angle passing through the target tooth through this teaching. In FIG. 15, the illustration of the X-ray tube arm 21 and the detector arm 22 is omitted.

Specifically, as shown in FIG. 15, the teaching arm 25 is L-shaped and has a substantially round bar shape, and its base is fixed to the rotation mechanism 170. For this reason, this teaching arm 25 can be rotated (rotated) around the face of the subject P (see arrow F1 in the figure). The rotation mechanism 170 is provided with an encoder 171, detects the rotation angle of the entire teaching arm 25 (hereinafter referred to as the arm rotation angle θ1), and outputs a detection signal to the CPU of the controller 133 of the console 15. Is done.

Further, the teaching arm 25 is a rod-like arm that is formed in an L shape as a whole, and includes a base side arm portion 25A and a tip side arm portion 25B. The base side arm portion 25A extends to a part in the Z-axis direction, and the distal end side arm portion 25B is rotatably connected to the end portion of the arm portion. The distal end side arm portion 25B extends in the Z-axis direction, and the end portion on the distal end side reaches above the jaw portion JW of the subject P.

The distal end portion of the base side arm portion 25A incorporates a rotation mechanism 172 that rotatably supports the distal end side arm portion 25B at the distal end portion, and an encoder 173 provided therewith. For this reason, when the front end side arm portion 25B is twisted, it can be rotated (turned) with respect to the base side arm portion 25A. This amount of rotation is also detected by the encoder 173, and the detection signal is sent to the CPU of the controller 133.

In addition, a small laser oscillator 181 and a push button switch 182 are provided at predetermined positions on the distal end side of the distal end side arm portion 25B. The laser oscillator 181 can irradiate a laser beam LB toward the dentition TR of the subject P from the side surface on the distal end side of the arm. The push button switch 182 is provided at the distal end of the distal arm portion 25B and can be pressed by a dentist. This switch signal is sent to the CPU of the controller 133.

The dentist can grasp the distal end side arm portion 25B of the teaching arm 25 and rotate it to irradiate the beam to a desired position of the dentition TR and confirm the position. Further, the irradiation angle of the laser beam can be changed by twisting (rotating) the distal end side arm portion 25B. Thus, even at the same rotational position of the teaching arm 25, the incident angle of the laser beam LB, that is, the irradiation angle of the actually irradiated X-ray beam XB (by changing the twist angle of the distal arm portion 25B) That is, the swing angle θ2) can be changed (see FIG. 16).

The laser oscillation point PT of the laser oscillator 181 is configured to be able to rotate on the same circular orbit as the X-ray focal point FP of the X-ray tube 23 described above. For this reason, the laser beam LB emitted from the laser oscillator 181 can simulate the X-ray beam XB at the time of actual imaging. For this reason, at the time of teaching, the X-ray tube arm 21 and the detector arm 22 are positioned at their standby positions so as not to disturb the manual teaching operation of the dentist. This retracted position is set to a position obliquely below the head of the subject P that is outside the teaching range.

Next, processing related to teaching executed by the controller 133 (actually the CPU) will be described.

As shown in FIG. 17, after initialization (step S11), the controller 133 first attempts to read the output signals from both encoders 171 and 173, and determines whether or not the arm rotation angle θ1 has been input (step). S12, S13). The dentist determines the desired arm rotation angle θ1 and swing angle θ2, and presses the push button switch 182. In response to this, the controller 133 can assume that the arm rotation angles θ1 and θ2 have been determined (step S14, YES). If this determination is NO, since the dentist is still in a trial and error stage to determine the arm rotation angle θ1, the process returns to step S2 and waits while repeating the processes of steps S12 to S14.

Next, the controller 133 proceeds to Step 15 and displays the arm rotation angle θ1 and the swing angle θ2 determined in a simulated manner on the display 136 (or a portable monitor at hand). If the dentist does not agree with the display result, the process returns to step S12, and the arm rotation angle θ1 and the swing angle θ2 are set again (NO in step S16).

On the other hand, if the angles θ1 and θ2 set by the dentist are agreed (step S16, YES), the speed for translation in the opposite direction of the X-ray tube 23 and the detector 24 based on the angles θ1 and θ2 A pattern is calculated as control data (step S17). The calculated control data is sent to and stored in, for example, the first storage unit 134 (step S18).

Here, the algorithm for calculating the speed pattern (control data) executed in step S17 will be described with reference to FIG. In the figure, it is assumed that the tooth number 3 in the tooth row TR is the target tooth.

First, the midpoint of the line connecting the X-ray tube focal point and the detector surface at the oblique line at the position of the tooth number 3 and the intersection of the oblique line and the dentition ellipse TR are calculated. Although two intersection points are obtained, the intersection point closer to the detector 24 is adopted. Here, the slanted line indicates a line of the swing angle θ2 at the arm rotation angle θ1 simulated by the laser beam. The detector 24 always moves in front of the subject.

・ Draw a line that passes through this intersection and is perpendicular to the diagonal line, and calculate two points of 25mm forward and backward from the intersection on the vertical line.

・ Next, create two straight lines that pass through these two points and the midpoint.

· Intersection points between these two lines and the orbital circles Ts and Td of the X-ray tube 23 and the detector 24 are respectively calculated.

· The respective start positions (arm angle and swing angle) are determined so that the X-ray tube 23 and the detector 24 face each other.

The X-ray tube 23 and the detector 24 on the orbital circles Ts and Td during imaging trajectory control are divided into a range from the start position to the teaching position and a range from the teaching position to the end position, respectively. The position is calculated for both the X-ray tube 23 and the detector 24, and the above-described velocity pattern is calculated so that the X-ray tube 23 and the detector 24 face each other at the respective positions.

The speed pattern of the 4-axis independent control of the X-ray tube 23 and the detector 24 set in this way is output as control data.

In the present embodiment, the teaching device is configured with the processing of the controller 133, the first storage unit 134, the rotation mechanisms 170 and 172, the encoders 171 and 173, the laser oscillator 181 and the push button switch 182 as main parts. And integrated into the panoramic photographing apparatus 1. In the case of the present embodiment, since the teaching device is integrated in the panoramic photographing device 1, it is advantageous in that the panoramic photographing device 1 can use the teaching control data as it is.

When using the panoramic photographing apparatus 1 according to the present embodiment, first, the panoramic photographing apparatus 1 is positioned at a predetermined position on the back side of the dental treatment chair 2 and fixed to the floor surface. At this time, the operation lever 52 described above is operated to push the pin 50 down, and the pin 50 is engaged with the floor fixing portion 53. Thereby, positioning and fixation with respect to the dental treatment chair 2 of the main body BD of the panoramic imaging apparatus 1 are achieved.

Next, the scattered radiation shielding cover 14C is retracted to the rear side (see the imaginary line “retraction position” in FIG. 3). At this stage, the X-ray tube arm 21 and the detector arm 22 are positioned at their initial positions. Therefore, the dentist positions the head H of the patient P at a predetermined position in the imaging space S while tilting the backrest of the dental treatment chair 2. This positioning is performed by adjusting the height direction of the elevator 14 and positioning the midline, Frankfurt, and canine by three laser beams (not shown).

After the positioning, the scattered radiation shielding cover 14C is moved to the imaging position in the forward direction (see the solid line “imaging position” in FIG. 3). As a result, as shown by the solid line in FIG. 3, the head H of the subject P is positioned in the defined imaging space S. In this state, the dentist presses the irradiation switch 56 from a slightly separated position, whereby the panoramic imaging described above is activated and the frame data related to the above-described four-axis independent control is collected.

Next, precision photography will be explained as necessary. In this case, after the head H of the subject P is positioned in the imaging space S as described above (the scattered radiation shielding cover 14C is empty, and the X-ray tube arm 21 and the detector arm 22 are retracted). In this state, the above-described teaching is performed to set control data for precisely photographing a desired imaging range. Thereafter, the scattered radiation shielding cover 14C is closed and the apparatus 1 is operated in the same manner.

In this case, the velocity pattern set as the control data is an attitude in which scanning is performed in a state in which the X-ray tube 23 and the detector 24 face each other in some specified ranges of the trajectories Tx and Td of the detector 24, respectively. Control data. For this reason, during scanning, X-ray irradiation is executed only in those designated ranges, and data collection in a partial designated range is executed. The collected frame data is synthesized using the tomosynthesis method to obtain a precision photographed image similar to a conventional dental X-ray. Therefore, the discomfort and inconvenience of both the patient and the dentist when using the conventional dental X-ray can be solved.

Thus, according to the present embodiment, partial X-ray imaging aiming at several teeth can be performed. For this purpose, the center position of the imaging range is designated, and the incident direction of the X-ray beam in which the overlapping of teeth in the region is eliminated as much as possible is designated. By specifying the center position, the imaging range of the dentition can be determined from a predetermined length. The command values for the X-ray imaging range and the incident angle of the X-ray beam can be simulated in advance with a laser beam before actual scanning, and the command values (control data) can be set accurately. This command value is reflected in actual X-ray imaging. As a result, it is possible to improve the accuracy of the image and prevent re-taking of precision imaging as much as possible, and to contribute to the reduction of the X-ray exposure amount, the patient's pain and burden, the operator's labor, and the patient throughput.

[Third Modification]
Next, with reference to FIG. 25, one modification of teaching according to the second embodiment described above will be described as a third modification.

The teaching according to the third modification is a simple method that does not necessarily require the teaching arm 25 to be used. In this method, as shown in FIG. 10, assuming that the dentition TR of the subject P draws a standard trajectory SS, the rotation angle θ in the circumferential direction of each tooth (target tooth) constituting the dentition TR is shown. The position of is fixed. Therefore, a speed pattern can be calculated and stored in advance based on the algorithm of FIG. 18 described above for each target tooth. In this case, for each of the maxillary and mandibular teeth arranged along the standard trajectory SS, the corresponding rotation angle θ is determined, the direction orthogonal to the teeth is determined, for example, and the speed pattern is calculated from the angle and direction. is there. That is, for each tooth, an area of about 50 × 50 mm around the tooth can be partially scanned. A table in which the tooth number and the speed pattern are associated with each other may be stored in the first storage unit 134, for example. As described above, one set of velocity patterns is composed of four velocity patterns by revolution and rotation of the X-ray tube 23 and the detector 24. Furthermore, tooth numbers, a plurality of X-ray incident angles on each tooth, and a plurality of sets of velocity patterns corresponding to each tooth and each X-ray incident angle may be prepared.

FIG. 25 illustrates a set of speed patterns for partial shooting for adults that are actually calculated. In FIG. 4A, the speed pattern (curve A) of rotation (part of revolution) of the X-ray tube 23 with respect to the teeth of “left, lower jaw, third”, rotation of the detector 24 (part of revolution). 2 shows a speed pattern (curve B ′), a rotational speed pattern (curve A ′) of the X-ray tube 23, and a speed pattern (curve B ′ showing partial rotation) of the X-ray tube 23 of the detector 24. FIG. 4B shows a set of similar speed patterns for the “left, lower jaw, and number 7” teeth.

The above-mentioned speed pattern data only needs to designate on the GUI screen of the display 136 the target tooth that the dentist wants to diagnose at the time of partial imaging. For example, if the “left, lower jaw, third” tooth is designated in step S3 of FIG. 24 described above, the controller 133 reads a set of operation patterns shown in FIG. 25A from the first storage unit 134, The partial imaging of the target tooth can be performed according to the procedure shown in FIG. This partial imaging, that is, a partial area centered on the target tooth may be scanned (partial scan), and the frame data collected thereby may be reconstructed with a predetermined profile of the shift and add amount. Thereby, a partial captured image similar to that of a conventional dental X-ray can be obtained.

Therefore, according to the third modified example, although it is simple, a partial captured image can be obtained by designating only the target tooth, so that the labor of the dentist is reduced and the X-ray exposure is reduced. The reason why such a simple partial photographing can be adopted is that the patient's dentition is often along the standard trajectory SS although there are individual differences.

According to each of the above-described embodiments and their modifications, various effects other than those described above are brought about. First, the top surface, both side surfaces, and the bottom surface that define the imaging space S are surrounded by the above-described scattered radiation shielding cover 14C and the scattered radiation shielding plate 20 of the bottom surface portion 14C, and are subjected to X-ray shielding. ing. For this reason, X-rays leaking outside from the imaging space S during panoramic imaging or partial imaging can be reliably reduced or shielded. Thereby, even when panoramic imaging or partial imaging driven by the X-ray tube 23 is performed, the influence of X-rays on the outside of the imaging space S can be almost ignored.

This panoramic photographing apparatus 1 is movable. Therefore, it is possible to provide a panoramic imaging apparatus having an X-ray shielded space that should be called a “portable dental X-ray shield room”. Thereby, X-ray imaging | photography of a jaw part can be performed with the patient lying in the dental treatment chair on its back. Leakage to the outside from a very localized small imaging space around the jaw during the imaging can be greatly reduced.

Further, for the subject, the head H is put in the scattered radiation shielding cover 14C, and the translucent portion 14TR is provided in the cover 14C. For this reason, the outside can always be seen, and even patients who are not good at closing can be handled.

On the other hand, in the embodiment and the modification described above, the caster 11 is provided as a moving means for moving the main body BD (excluding the console) of the apparatus 1. However, this moving means is not limited to casters. A gripping portion may be provided on the main body of the apparatus 1, and the gripping portion may be held and moved by hand. Moreover, you may provide the wheel which rotates electrically on the lower surface of the base part 12. FIG. Any means capable of freely moving the main body BD of the apparatus 1 according to the present application to the side of the dental treatment chair 2 may be used.

[Third Embodiment]
Next, various examples of an X-ray panoramic imaging apparatus having an X-ray shielding structure that can be mounted on the X-ray imaging apparatus according to the present invention will be described as a third embodiment with reference to FIGS. To do.

First, in the case of the embodiment shown in FIG. 26, a scattered radiation shielding plate (third shielding body) 31 made of a lead plate is fixedly arranged inside the back surface portion 14B of the elevator 14. At this time, it is convenient to make a hole in the scattered radiation shielding plate 31 so as to avoid the portion of the rotation center axis C such as a motor. This also gives the scattered radiation shielding function to most of the back side.

Further, in the case of the embodiment shown in FIG. 27, a warm X-ray protective curtain (fourth shield) 32 is also suspended from the vacant front surface (front surface) of the scattered radiation shielding cover 14C. The scattered radiation shielding cover 14 </ b> C originally has little scattering of scattered radiation (the same applies to the back side), but as a further countermeasure against scattered radiation, the front is also subjected to X-ray shielding. When the head H of the subject P is positioned inside the imaging space S and ready for imaging, the operator manually places the X-ray protective curtain 32 on the plurality of hooks 33 attached to the edge of the scattered radiation cover 14C. It is designed to be hung by. The X-ray protective curtain 32 is formed by connecting, for example, a plurality of strip-shaped portions in which lead is contained in a flexible resin and has an X-ray shielding function. A portion of the X-ray protective curtain 32 that corresponds to the neck portion of the subject is cut out in a substantially semicircular shape along the shape.

Either or both of the X-ray shielding means according to the embodiment of FIGS. 26 and 27 may be adopted. When both X-ray shielding means are employed, the X-ray shielding wall part that separates the imaging space S from the outside world is composed of all six surfaces including the front and back surfaces as schematically shown in FIG. Will cover. Thereby, the scattered radiation leaking out from the imaging space S at the time of imaging can be further reliably reduced, and the scattered radiation shielding function described above is further strengthened. Therefore, the influence of X-rays on the outside of the imaging space S due to imaging can be almost ignored, and the reliability of X-ray protection can be further enhanced. Of course, this is the same even when the X-ray shielding means of either FIG. 26 or FIG. 27 is adopted.

In addition, the X-ray protective curtain 32 may be a single plate made of a resin plate containing lead.

[Fourth Embodiment]
Next, an X-ray imaging apparatus according to the fourth embodiment of the present invention will be described with reference to FIGS. This X-ray imaging apparatus is implemented for an X-ray panorama apparatus, and is equipped with the positioning mechanism described in each of the above-described embodiments. In this embodiment, the positioning mechanism will be described in detail.

29 and 30 show a side view and a rear perspective view of the X-ray panoramic imaging apparatus 1A according to the third embodiment, respectively. This X-ray panoramic imaging apparatus 1A includes a side handle 55 for conveyance on both sides of the apparatus in addition to the same configuration as the X-ray panoramic apparatus shown in FIG. The moving handle 54 is also provided on both sides as shown in FIG.

A multipurpose storage rack 56 and a monitor 57 indicating the operating state of the apparatus 1A can be detachably attached to one of the two side handles 55. The storage rack 56 can store a terminal such as a dentist PC for inputting patient information or the like to the apparatus 1. These terminals and the monitor 57 can communicate with a control circuit (not shown) disposed inside the console 15 or the power supply box 13 by, for example, wireless communication. Further, an irradiation switch 58 for instructing X-ray irradiation and rotation of the X-ray tube / detector via a cord 58C having a length of 2 m, for example, is provided on the back surface portion 14B.

In this embodiment, a positioning element having functions equivalent to those of the fixing pin 50, the cover portion 51, and the floor fixing portion 53 shown in FIG. Specifically, as shown in FIG. 29, a positioning mechanism unit for stopping and positioning the position of the panoramic imaging apparatus 1A on the side of the dental treatment chair 2 at the front end of the pedestal unit 12 of the main body BD. 61 is provided. The positioning mechanism 61 includes a stop pin 62 and a positioning pin 63 which will be described later. The positioning pin 63 moves up and down in conjunction with an operation lever 52 (see FIG. 30) provided on the upper edge of the back surface part 14B via a wire mechanism described later. On the other hand, at a predetermined position of the floor surface F on the rear surface side of the dental treatment chair 2, a substantially triangular shape can be formed in a side view, and the abutment pin 62 can be contacted, and a positioning pin 63 can be inserted. A floor fixing portion 71 having a hole is fixed. For this reason, if the apparatus main body BD is moved, the tip position thereof is aligned with the position of the floor fixing portion 71, and the operation lever 52 is operated with the stop pin 62 in contact with the floor fixing portion 71. The positioning pin 63 can be pushed down. When the positioning pin 63 enters a hole (described later) of the floor fixing portion 71, the apparatus main body BD is positioned at a predetermined position with respect to the dental treatment chair 2 as in the positioning state shown in FIG.

Furthermore, when the panorama photographing apparatus 1A (that is, the apparatus main body BD) is moved to another place, the operation lever 52 is operated to raise the positioning pin 63. Thereby, apparatus main body BD can be released from position fixing with floor fixing | fixed part 71, and apparatus main body BD can be moved to another place.

Note that the configuration and shooting functions other than those described above are equivalent to the configuration and shooting functions described in the first embodiment.

In order to move the apparatus main body BD, a rear handle 54 is fixed to the upper end portion of the rear portion 14B so as to be positioned on both sides of the operation lever 52. For this reason, the operator can easily move the apparatus main body BD by freely rotating the caster 11 by pulling and pushing the two rear handles 54.

Furthermore, this apparatus main body BD is provided with a substantially inverted U-shaped side handle 55 that is fixed at one end on the bottom surface of the pedestal portion 12 and rises vertically from the side. The side handle 55 is formed of a metal pipe, for example. For this reason, of course, when the apparatus main body BD is moved, the carrier can use the side handle 55, while the apparatus main body BD is pushed or pulled in the lateral direction, particularly at the positioning described above. Thus, the position can be easily finely adjusted.

A guide pole 59 for a guideline is attached to a position on the side surface of the power supply box 13 below the back surface portion 14B while being suspended toward the floor F as shown in FIG. The tip of the reference pole 59 on the floor surface side is close to the floor surface F. On the other hand, as shown in FIG. 30, a guideline GL made of tape, paint, or the like arranged on the floor surface F is laid on the floor surface F toward the floor fixing portion 71 described above. Therefore, when the apparatus main body BD is moved toward the floor fixing portion 71, that is, toward the dental treatment chair 2, the apparatus main body BD can be easily moved by pushing the tip of the guide pole 59 so as to follow the guideline GL. In addition, the dental treatment chair 2 can be easily accessed. When the stop pin 62 comes into contact with the predetermined surface of the floor fixing portion 71 and stops, the positioning pin 63 is driven by operating the operation lever 52 described above to achieve the positioning described above.

Based on the above configuration, the X-ray shielding room (that is, the device 1A) can be easily carried to an arbitrary place by the caster 11 by grasping and pushing the back handle 54 and can be used there.

<Positioning mechanism>
A positioning mechanism for positioning the panoramic imaging apparatus 1A with respect to the dental treatment chair 2 will be described.

Of course, the main part of this positioning mechanism is provided in the panoramic photographing apparatus 1A itself, but also includes a positioning floor fixing unit 71 fixed to the floor surface F.

As shown in FIGS. 30 and 31, the elevator 14 of the panoramic photographing apparatus 1 </ b> A has an operation lever 52 fixed to a predetermined portion on the upper edge of the back surface portion 14 </ b> B, and a lever drive for supporting and driving the operation lever 52. Part 81. The operation lever 52 is provided for the operator to manually tilt and fix the position of the panoramic photographing apparatus 1A.

As shown in FIGS. 31A and 31B, the lever driving portion 81 includes a support shaft 82 erected at the predetermined portion and a rotation shaft 183 pivotally supported by the support shaft 82. And have. An operation lever 52 is fixed to the rotating shaft 183. For this reason, if the operating lever 52 is grasped and rotated, the rotating shaft 183 also rotates integrally. A hole HL for inserting a hand is opened in the upper part of the operation lever 52 so as to be easily gripped, but an inflating part 52A that swells round in a side view is partially formed in the lower part thereof. The inflatable portion 52A is in contact with a ball plunger 84 provided upright at the predetermined portion. The ball plunger 84 is locked to the operation lever 52 at positions where the angle of the operation lever 52 is 0 ° (horizontal), 45 °, and 90 ° (vertical), and when the tilting power is applied more than a certain level, It is possible to rotate between.

Furthermore, as shown in FIGS. 31A and 31B, the lever driving portion 81 has first and second links 85A and 85B provided on one end side of the rotating shaft 183. One end of the first link 85A is fixed to one end of the rotating shaft 183. For this reason, the first link 85A swings as the rotation shaft 183 rotates. One end of the second link 85B is fixed or rotatable to the other end of the first link 85A, and converts the swing motion of the first link 85A into a reciprocating motion. A wire 86 is connected to the other end of the second link 85B.

For this reason, as shown in FIG. 31 (B), the operation lever 52 is erected in an initial position P1 (90 ° tilt position), and an intermediate position P2 tilted forward from the position P1 (45 ° tilt position). Further, it is possible to take a three-stage operation position called a fixed position P3 (a tilt position of 0 °) tilted further forward from the position P2, and to lock each operation position with a certain resistance. On the contrary, the operation lever 52 can be returned in the order of positions P3, P2, and P1. The operator operates the operation lever 52 while resisting a certain resistance by the ball plunger 84, and when a position P1, P2, P3 is reached, a click feeling is obtained, and at that position, a certain resistance is applied. Locked. Further, as the operation lever 52 is tilted from the initial position P1 to the intermediate position P2 and the fixed position P3, the wire 86 moves in the direction indicated by the arrow A in FIG. If the operation lever 52 is tilted in the opposite direction, the wire 86 moves in the direction indicated by the arrow B in FIG.

The wire 86 is loosely inserted inside the sheath SF. The sheath SF is fixed and piped inside the elevator 14 so as to avoid the internal mechanism and to form a linear path as much as possible. For this reason, the wire 86 moves in the directions indicated by arrows A and B in FIG.

The tip of the wire 86 reaches the tip on the front side of the pedestal portion 12 and reaches the inside of the pin cover 91 that is fixedly extended to the tip. The pin cover 91 is fixed to the distal end portion of the pedestal portion 12, and projects from the distal end side by a certain distance in a bowl shape (see FIGS. 29 and 32).

Inside the pin cover 91, a step-like support portion 92 fixed to the pedestal portion 12 is provided, and the positioning mechanism portion 61 described above is provided between the support portion 92 and the pin cover 91. Yes. The positioning mechanism 61 includes the stop pin 62 and the positioning pin 63 described above.

33. As shown in FIG. 33, the step portion 92A of the support portion 92 is integrally provided with substantially rectangular parallelepiped protrusions 92B at both ends in the lateral direction, that is, in the X-axis direction. The step portion 92A is provided with four guide holes H1, H2, H3, and H4 in a line along the lateral direction. Of these, guide holes H1 and H4 at both ends are guide holes for guiding the positioning pin 63 in the vertical direction. The guide holes H1 and H4 penetrate the stepped portion 92A and the protruding portion 92B in the vertical direction.

As shown in FIG. 34, positioning pins 63 are held and accommodated in the guide holes H1 and H4, respectively, and can move up and down along the guide holes H1 (H4). The positioning pin 63 is, for example, a metal cylindrical rod having a predetermined diameter, and has an annular protrusion 63A in the middle in the vertical direction. Similarly, annular protrusions HT1 and HT2 are respectively provided at the positions of the upper and lower ends of the guide hole H1 (H4) in the vertical direction. Therefore, as shown in FIG. 34, the distance L1 between the projection 63A in the middle of the pin 63 and the projection HT2 at the lower end of the guide hole H1 (H4) is set as the movable range in the vertical direction of the positioning pin 63. Yes.

Furthermore, a coiled spring 93 is inserted in a space between the protrusion 63A of the positioning pin 63 and the protrusion HT1 on the upper end side of the guide hole H1 (H4). When a certain force is applied to the positioning pin 63, the pin 63 takes the initial position Q1 indicated by the solid line in FIG. This initial position Q1 is obtained by a “large” pulling force acting in the direction indicated by the arrow B described above when the operation lever 52 is at the initial position P1 (90 ° tilt position). In this case, the upper end of the positioning pin 63 is flush with the upper surface of the projecting portion 92B of the support portion 92, and the lower end is almost flush with the lower surface of the stepped portion 92A. That is, the positioning pin 63 is accommodated in the guide hole H1 (H4).

Furthermore, when the operation lever 52 is tilted to the intermediate position P2 (45 ° tilt position), the wire moves in the direction of the arrow A, and the force applied to the spring 93 becomes “small”. As a result, the elastic force of the spring 93 is increased by the decrease in the force, and the positioning pin 63 is pushed downward.

Further, when the operation lever 52 is tilted to the fixed position P3 (0 ° tilt position), the wire further moves in the direction of the arrow A, and the force applied to the spring 93 becomes “0”. As a result, the spring 93 has only its own elastic force, and the positioning pin 63 is further lowered.

On the other hand, as shown in FIGS. 32 and 33, the positioning mechanism portion 61 is a mechanism for moving the two positioning pins 63 up and down in accordance with the movement of the wire 86. Specifically, the tops of the two positioning pins 63 are rigidly connected to the suspension shaft 63C. The suspension shaft 63 </ b> C of both the pins 63 is fixed to the lateral arm 101 that is laterally mounted in the lateral direction, that is, the X-axis direction. The horizontal arm 101 is pivotally supported by two rings 102 at predetermined positions on both ends thereof. Further, the two rings 102 are supported by the two arms 103 so as to roll along the upper surface thereof. The two arms 103 are rigidly connected to a single link 104, and the link 104 is rigidly connected to the rotating arm 105. The rotating arm 105 is further coupled to the wire 86 described above via a connecting body 106.

The guide holes H1 and H4 described above are formed with a slit-like opening OP over a predetermined length from the upper end side of the guide holes H1 and H4 in order to allow the horizontal arm 101 to move in the vertical direction. (See FIG. 33).

Furthermore, at least one of the guide holes H1 and H4 is provided with three hall sensors 111A, 111B, and 111C so as to be slightly recessed from the inner surface. The three hall sensors 111A to 111C are detection means for detecting the vertical movement of the positioning pin 63. Therefore, the positions of the three hall sensors 111A to 111C in the vertical direction, that is, the Y-axis direction are respectively the distances of an initial position Q1, a first-stage descending position Q2, and a second-stage descending position Q3, which will be described later. Correspondingly, the distance is set to be the same. Note that the two lower positions Q2 and Q3 other than the initial position Q1 are positions determined by the lower end of the positioning pin 63 being restricted by the bottom of the two-stage groove and hole described later of the floor fixing portion 71 by the extension of the spring 93. It is.

On the other hand, a magnet 112 is embedded in the outer peripheral surface of the positioning pin 63 so as to face the uppermost hall sensor 111A at the initial position Q1. As a result, the Hall sensor 111A is positioned in the magnetic flux generated from the magnet 112, so that the Hall sensor 111A generates a voltage and outputs the voltage signal. The hall sensors 111A to 111C send voltage signals to the control circuit of the power supply box 13 described above via lead wires (not shown).

On the other hand, as shown in FIGS. 32 and 33, two stop pins 62 are fixedly provided in the two middle guide holes H2 and H3 described above. That is, each of the two stop pins 62 includes a fixing member 62A, and the fixing member 62A is fixed to the stepped portion 92A. For this reason, in the present embodiment, the heights of the lower ends of the two stopping pins 62 are kept constant. The diameter of the guide hole H2 (H3) that accommodates the stop pin 62, that is, the diameter of each stop pin 62 is larger than that of the above-described guide holes H1, H4, that is, the positioning pins 63. The reason is that the object body BD pushed by the operator is brought into contact with the floor fixing portion 71 and stopped before positioning, and it is necessary to have sufficient strength. It is necessary to prevent the apparatus main body BD from colliding with the dental treatment chair 2 due to inertia or the like.

Furthermore, the floor fixing portion 71 will be described with reference to FIGS. The floor fixing portion 71 is a horizontally long member made of resin or metal, and is fixed to the floor surface F near the headrest when the backrest of the dental treatment chair 2 is tilted with screws or the like. The floor fixing portion 71 is configured such that a cross section thereof in the horizontal direction, that is, the Z-axis direction here is shown in FIG. As can be seen from the figure, a gentle slope 71A starts from the front end, and a long groove 71B dug shallowly along the longitudinal direction, that is, the X-axis direction in this case, lies at the back (see FIG. 35). At two locations in the longitudinal direction of the long groove 71B, two positioning holes 71C that are further dug from the bottom surface are formed. The interval between the two positioning holes 71C is the same as the interval between the two positioning pins 63 described above.

Further, the long groove 71B follows the steep contact surface 71D with which the stop pin 62 can contact, and the contact surface 71D passes through the top portion 71E and falls to the back side, that is, the dental treatment chair 2 side and ends. . The bending state of the contact surface 71D is made to match the curved shape of the distal end portion of the stop pin 62 as described above.

The output signals of the three hall sensors 111A, 111B, and 111C described above are sent to the control circuit of the power supply box 13. For example, as shown in FIG. 37, this control circuit includes a processor 120 constituted by a CPU. The processor 120 turns on / off the red, yellow, and blue LEDs 121A, 121B, and 121C depending on which Hall sensor has an output signal and the detection state thereof. These LEDs 121A, 121B, and 121C are installed, for example, at the upper end portion of the back surface portion 14B of the main body BD. When receiving an output signal from the first hall sensor 111A, the processor 120 turns on the red LED 121A and turns off the remaining LEDs 121B and 121C. Further, when receiving an output signal from the second hall sensor 111B, the processor 120 turns on the yellow LED 121B and turns off the remaining LEDs 121A and 121C. Similarly, when an output signal is received from the third hall sensor 111C, the blue LED 121C is turned on and the remaining LEDs 121A and 121B are turned off.

The panoramic photographing apparatus 1A according to the present embodiment is configured as described above. For this reason, various effects are exhibited as described below.

First, since this panoramic photographing apparatus 1A is configured to be portable, it can be easily moved by a dentist or a nurse. When positioning the panoramic imaging apparatus 1A on the back side of the dental treatment chair 2, the dentist or nurse holds the back handle 54 and pushes the apparatus 1A while keeping the guide pole 59 along the guideline GL. That's fine. The tip of the guide line GL reaches the center position C in the longitudinal direction of the floor fixing portion 71 on the floor surface F (see FIG. 35). This center position C is matched with the lateral center position of the headrest when the backrest of the dental treatment chair 2 is tilted.

Then, when it is considered that the tip of the positioning mechanism 61 of the apparatus 1A has reached the floor fixing portion 71, the device is further advanced while reducing the pressing speed slightly. Accordingly, the two stop pins 62 discharged from the lower surface of the positioning mechanism portion 61 by the predetermined height L2 come into contact with the contact surface 71D of the floor fixing portion 71. Since the floor fixing portion 71 is fixed to the floor surface F, the panorama photographing apparatus 1A also stops when it comes into contact with the contact surface 71D (see FIG. 32). At this time, the tips of the two positioning pins 63 are stored at the initial position Q1 (see FIG. 34), and are positioned directly above the long groove 71B of the floor fixing portion 71. At this time, since the red LED 121A is lit by the output signal of the first hall sensor 111A, it can be notified that the positioning has not been performed yet.

When this conveyance is completed, the operator tilts the operation lever 52 from the initial position P1 to the intermediate position P2. In response to this, the wire 86 is pushed (loosened) and the turning arm 105 is also rotated forward (see FIG. 32, arrow A), the spring 93 has excellent elastic force, and the two positioning pins 63 are moved downward. Pressed. As a result, the two positioning pins 63 are dropped into the long groove 71 </ b> B of the floor fixing portion 71. That is, the lower end of the positioning pin 63 shifts from the initial position shown in FIG. 34 to the first-stage lowered position Q2. In response to this, the yellow LED 121B is turned on by the output signal of the second hall sensor 111B. This informs the operator that the positioning has not yet been done, but that the first stage of positioning has been completed.

Therefore, the operator tilts the operation lever 52 from the intermediate position P2 to the fixed position P3. In response to this, the wire 86 is further loosened and the rotating arm 105 is further rotated forward (see arrow A in FIG. 32), and the two positioning pins 63 are further pushed downward. At this time, if the positions of the tips of the two positioning pins 63 coincide with the two positioning holes 71C at the bottom of the long groove 71B, the pins 63 are dropped into the positioning holes 71C as they are (FIG. 34). (Refer to the lower position Q3 of the second stage). In this lowered state, the positioning mechanism portion 61 is locked to the floor fixing portion 71 by the urging force of the spring 93. When in this locked state, the spring 93 is almost fitted in the positioning hole 71C and exerts a force to stretch against the floor surface F. Accordingly, the apparatus main body BD, that is, the panorama photographing apparatus 1A is positioned by the position of the floor fixing unit 71. That is, the panoramic photographing apparatus 1A is positioned in a fixed state with respect to the dental treatment chair 2 at a predetermined position. At this time, since the output signal of the third hall sensor 111C becomes valid, the blue LED 121C is lit. Thereby, the completion of positioning is notified.

However, at the above-described drop-in stage, the tip ends of the two positioning pins 63 may be slightly displaced from the positions of the two positioning holes 71C. In such a case, the operator may hold the back handle 54 or the side handle 55 and slightly move the apparatus main body BD left and right. Thereby, a pin position that matches the position of the positioning hole 71C can be found. If the positions match, the operating lever 52 is already in the fixed position P2 and the urging force of the spring 93 is working, so the two positioning pins 63 automatically click into the two positioning holes 71C. Dropped and locked. That is, the positioning pin 63 changes from the first-stage lowered position Q2 to the second-stage lowered position Q3 shown in FIG. As a result, the blue LED 121C is lit and positioning is completed.

Next, the scattered radiation shielding cover 14C is retracted to the rear side (see the imaginary line “retraction position” in FIG. 3). At this stage, the X-ray tube arm 21 and the detector arm 22 are positioned at their initial positions. Therefore, the dentist (or operator) positions the head H of the patient P at a predetermined position in the imaging space S while tilting the backrest of the dental treatment chair 2. This positioning is performed by adjusting the height direction of the elevator 14 and The laser beam is applied to the midline, the Frankfurt plane, the occlusal plane and the canine.

After this patient positioning, the scattered radiation shielding cover 14C is moved to the imaging position in the forward direction. As a result, the head H of the subject P is positioned in the defined imaging space S. In this state, when the dentist presses the irradiation switch 58 from a position slightly away, the panoramic imaging described above is activated and data is collected. This series of photographing procedures is the same as that described in the first and second embodiments.

When the positioning and data collection described above are completed, the subject P is released from the imaging space S by opening the scattered radiation shielding cover 14C (retracted position) and returning the back of the dental treatment chair 2 to the original position. Next, the scattered radiation shielding cover 14C is closed (imaging position), and the panorama imaging apparatus 1A is moved to another location. At this time, the operation lever 52 may be continuously returned to the fixed position P3, the intermediate position P2, and the initial position P1. As a result, the wire 86 and the rotating arm 105 are returned (see FIG. 32, arrow B), and the positioning pin 63 returns to the initial position against the elastic force of the spring 93 and takes the initial position Q1. In response to this, the red LED 121A is turned on. Thereby, since the apparatus main body BD is released from the floor fixing | fixed part 71 (unlocking), the apparatus 1A can be moved to another place.

As described above, the panoramic photographing apparatus 1A can be freely moved and can be reliably and accurately positioned with respect to the dental treatment chair 2. At the time of this positioning, the apparatus main body BD is surely stopped first using the stop pin 62, so that the subsequent positioning can be performed easily and quickly. Furthermore, when accessing the dental treatment chair 2, the operator can obtain a guide function using the guide pole 59 and the guide line GL, so that the operations up to positioning are facilitated. Furthermore, since the pin state until the positioning is completed can be monitored by the LED, the operator can improve the positioning work efficiency.

In addition, the various functions and effects described above can be similarly obtained in the embodiment. Among these effects, the amount of scattered radiation that leaks in the front-rear direction of the imaging space S is very small, and X-ray shielding that should be called a “portable dental X-ray shielding room” is made. During imaging, the patient in the imaging space can be easily checked, and even patients who are not good at closing can be handled.

(Other variations)
In the case of the above-described embodiment, when the apparatus main body BD of the panoramic photographing apparatus 1A is moved to the dental treatment chair 2, the operator uses the guideline GL and the guide pole 59 as a guide. Various embodiments of the guide function are possible. For example, as shown in FIG. 20, a plurality of intersecting lines GLs such as “long”, “medium”, and “short” intersecting with each other can be pasted at a predetermined position of the linear guideline GL. The positioning pin 63 is set to be directly above the long groove 71B of the floor fixing portion 71 when the reference pole 59 reaches just above the shortest intersection line of the intersection line GLs. Therefore, when the guide pole 59 reaches the long intersection line GLs, the operator can surely know that the distal end portion of the apparatus main body BD is close to the dental treatment chair 2 and can surely enter the slow running system. . Therefore, the apparatus main body BD can be reliably positioned on the floor fixing portion 71.

38, a transmission / reception unit 131 that transmits and receives a medium such as a laser and an ultrasonic wave in a non-contact manner with the guide line GL may be provided in a part of the positioning mechanism unit 61. By processing the output signal of the transmission / reception unit 131 by, for example, the processor 120, the distance information to the floor fixing unit 71 can be known by voice or light. Furthermore, as shown in FIG. 39, a small camera 132 that photographs the front may be provided on the front surface of the positioning mechanism unit 61. This captured image may be displayed on a display (not shown) provided near the operation lever. According to these means 131 and 132, it is possible to reliably detect the front floor fixing portion 71 which is difficult to see, which greatly helps in positioning.

In the case of the above-described panoramic photographing apparatus 1A, the hall sensor is provided as a sensor indicating the pushing state of the positioning pin 63, but this may be another sensor. For example, a non-contact sensor such as an optical sensor may be used, or a physical contact sensor may be used. Further, the installation position of the sensor is not necessarily limited to the above-described embodiment, and may be a place where the movement of the positioning pin 63 can be detected. For example, a non-contact sensor or a contact sensor can be embedded on the floor fixing portion 71 side, the arrival of the positioning pin 63 being pushed in can be detected, and the detection signal can be sent wirelessly to the apparatus body BD. Thereby, the detection operation equivalent to embodiment mentioned above can be performed.

Further, a mechanism in which the stop pin 62 in the panoramic photographing apparatus 1A described above is omitted may be employed. In that case, it is desirable that the positioning pin also has a stopper function, and accordingly, a deformation such as increasing the diameter of the pin or increasing the number of pins to three or more is desirable.

Furthermore, only the positioning hole 71C may be provided in the floor fixing portion 71. That is, a structure in which the long groove 71B is not formed may be employed. In this case, the positioning pin 63 simply moves up and down in two stages. In this case, the operation position of the operation lever 52 also takes the two-stage operation position of the initial position P1 (90 ° tilt position) and the fixed position P3 (0 ° tilt position) in FIG. For this reason, when the tip of the positioning pin 63 that has been lowered in response to the tilting operation to the fixing position P3 of the operation lever 52 is aligned with the positioning hole 71C, it is directly fitted into the hole 71C and locked. Is done. However, if they do not match, the tip of the positioning pin 63 stops around the upper end of the positioning hole 71C. In this case, the operator can find the positioning hole 71C by holding the back handle 54 or the side handle 55 and slightly moving the apparatus main body BD left and right. When the positioning hole 71C is located, the positioning pin 63 is automatically lowered by the elastic force of the spring 93, and is locked as described above. For this reason, when adopting the structure for performing the two-stage operation, the opening at the upper end of the positioning hole 71C may be slightly wider and tapered so that the diameter is reduced.

Furthermore, the number of positioning pins 63 is not necessarily two, and may be three or more. Further, when the two positioning pins 63 are provided as in the above-described embodiment, the distance between the pins may be separated and positioned at both ends in the width direction of the apparatus main body BD, that is, in the X-axis direction.

Furthermore, in the case of a structure employing only the positioning pin 63, the positioning hole 71C may be directly formed in the floor surface F without providing the floor fixing portion 71 depending on the structure of the floor surface F. In this case, a removable lid may be attached to prevent dust and the like from accumulating in the positioning hole 71C when not in use.

Depending on the structure of the floor surface F, the above-described floor fixing portion 71 may be detachably attachable to the floor surface F.

Note that the present invention is not limited to the configurations shown in the above-described embodiments and modifications, and can be implemented with various modifications without departing from the spirit described in the claims.

1, 1A Dental X-ray panoramic imaging device (X-ray imaging device)
11 Casters (moving means)
12 Pedestal part 14 Elevator 14B Back part 14C Scattered ray shielding cover (forms a part of shielding body)
14L, 14R Side (first shield, wall)
14U Top surface (first shield, ceiling)
Cover (part of the shield)
14D bottom part 15 console (reading means, control means)
20 Scattered ray shielding plate (second shielding body)
21 X-ray tube arm 21A Opposing arm portion 21L Support portions 21B, 22B, 83; 145, 146, 147, 148, 149, 170, 171, 175, 173 (rotation drive portion (drive means))
22 Detector arm 22A Opposing arm portion 22L Support portion 23 X-ray tube 24 Detector 31 Scattered ray shielding plate (third shielding body)
32 X-ray protective curtain (fourth shield)
52 Operation lever 61 Positioning mechanism part 62 Stopping pin 63 Positioning pin 71 Floor fixing part (fixing frame)
71B Long groove 71C Positioning hole 81 Lever drive unit 91 Pin cover 133 Controller 134 First storage unit 135 Data processor 25 Teaching arm (forms part of teaching device)
25A Base side arm (first arm)
25B Front end side arm part (second arm part including arm gripping part)
133 Controller (part of teaching device)
134 1st memory | storage part (forms a part of teaching device)
135 Data processor 170 Rotation mechanism (forms part of teaching device)
171 Encoder (forms part of teaching device)
172 Rotating mechanism (part of teaching device)
173 Encoder (part of teaching device)
181 Laser oscillator (part of teaching device)
182 Push button switch (part of teaching device)
O Rotation center (Arm rotation center)
CA central axis (arm rotation central axis)
AXs first axis (X-ray tube swing axis)
AXd second axis (center axis of rotation of detector swing)
C Center position in the width direction of the detector (detection center position)
FP X-ray tube X-ray focal point (X-ray focal point position)

Claims (38)

An X-ray tube having a point-like focus and irradiating X-rays extending from the focus;
A detector that detects the X-rays emitted from the X-ray tube and outputs data corresponding to the amount of the X-rays, and has a predetermined rotation center for the X-ray tube and the detector. In an X-ray imaging apparatus capable of rotating around a central axis passing through
A tube housing that houses the X-ray tube so that the X-ray tube emits X-rays, and a tube support that rotatably supports the tube housing around a first axis parallel to the central axis An X-ray tube arm with a portion;
First driving means for rotating the tube housing portion around the first axis with respect to the tube support portion;
A detector accommodating portion that accommodates the detector so as to make the X-ray incident thereon; and a detector supporting portion that rotatably supports the detector accommodating portion around a second axis parallel to the central axis. A detector arm with
Second driving means for rotating the detector housing portion around the second axis with respect to the detector support portion;
A third driving means for supporting the X-ray tube arm and the detector arm so that they can be driven coaxially independently of each other, and driving both arms to rotate around the central axis;
The X-ray tube arm, the detector arm, the tube housing portion, and the detector housing portion according to a speed pattern for rotating the X-ray tube arm independently of each other for scanning by the X-ray. And control means for controlling the third drive means;
An X-ray imaging apparatus comprising: A first distance from the central axis to the first axis is set to a value greater than a second distance from the central axis to the second axis;
The X-ray imaging apparatus according to claim 1, wherein the X-ray tube and the detector are rotatable along mutually different circular orbits. The tube arm and the detector arm are arranged in an imaging space covered with a scattered radiation shielding body that shields the scattered radiation of the X-ray in a radial direction along a cross section orthogonal to the central axis. The X-ray imaging apparatus according to claim 1 or 2. The speed pattern includes a first speed pattern for rotating the tube arm about the central axis, a second speed pattern for rotating the detector arm about the central axis, and the tube receiving portion. A third speed pattern for rotating the detector around the first axis, and a fourth speed pattern for rotating the detector housing portion about the second axis. Item 4. The X-ray imaging apparatus according to any one of Items 1 to 3. The X-ray imaging apparatus is a dental X-ray panoramic imaging apparatus,
The first, second, third, and fourth speed patterns are speed patterns for scanning the X-rays so as to optimally focus on a reference tomographic plane that is set in advance for the dentition of the subject. The X-ray imaging apparatus according to claim 4, wherein: The X-ray imaging apparatus is a dental X-ray panoramic imaging apparatus,
The first, second, third, and fourth velocity patterns irradiate the X-ray beam so as to be orthogonal to a reference tomographic plane that is set in advance with respect to the dentition of the subject, and the reference The X-ray imaging apparatus according to claim 4, wherein the X-ray imaging apparatus is a speed pattern that scans the X-rays so that a tomographic plane is optimally focused. The speed pattern is a pattern in which the horizontal axis represents time when scanning a predetermined angle range around the central axis, and the vertical axis represents the angle of the predetermined angle range,
Storage means for presetting and storing the speed pattern;
7. An X-ray imaging apparatus according to claim 1, further comprising a reading unit that reads information on the speed pattern from the storage unit and provides the information to the control unit during the scan. . A laser beam simulating the actual irradiation of the X-ray is irradiated to the imaging region of the subject located in the imaging space between the tube housing unit and the detector housing unit, and partial imaging of the imaging site is performed. Teaching means that can indicate the range before shooting,
Setting means for decoding the partial photographing range instructed by the teaching means, and setting the speed pattern according to the decoding result;
The X-ray imaging apparatus according to claim 2, further comprising: The teaching means includes a teaching arm supported coaxially with the central axis, and a first rotational angle sensor that detects angular information indicating a rotational angle around the central axis of the teaching arm,
The teaching arm includes a first arm portion extending in a radial direction around the central axis, and a second arm extending from the first arm portion in a direction parallel to the central axis and outputting the laser beam. With arm part,
The second arm portion includes a distal arm portion, a remaining arm portion connected to the distal arm portion and rotatably supporting the distal arm portion, and the distal arm portion. A second rotation angle sensor for detecting angle information indicating a rotation angle with respect to the remaining arm portion,
The setting means includes angle information reading means for reading the angle information detected by the first and second rotation angle sensors, and a speed for calculating the speed pattern based on the angle information read by the angle information reading means. The X-ray imaging apparatus according to claim 8, further comprising a pattern calculation unit. The second arm portion includes laser output means for outputting the laser beam to the arm portion on the distal end side,
10. The X-ray imaging apparatus according to claim 9, wherein the output point of the laser output means is set to a spatial position imitating the position of the X focal point of the X-ray tube. The speed pattern includes a first speed pattern for rotating the X-ray tube arm about the central axis, a second speed pattern for rotating the detector arm about the central axis, and the tube. Including a third speed pattern for rotating the accommodating portion around the first axis, and a fourth speed pattern for rotating the detector accommodating portion about the second axis. The X-ray imaging apparatus according to any one of claims 8 to 9. The X-ray imaging apparatus is a dental X-ray panoramic imaging apparatus,
The first, second, third, and fourth speed patterns are speed patterns for scanning the X-rays so as to optimally focus on a reference tomographic plane that is set in advance for the dentition of the subject. The X-ray imaging apparatus according to claim 11, wherein: The X-ray imaging apparatus is a dental X-ray panoramic imaging apparatus,
The first, second, third, and fourth velocity patterns irradiate the X-ray beam so as to be orthogonal to a reference tomographic plane that is set in advance with respect to the dentition of the subject, and the reference The X-ray imaging apparatus according to claim 11, wherein the X-ray imaging apparatus is a speed pattern that scans the X-ray so as to optimize a tomographic plane. The speed pattern is a pattern in which the horizontal axis represents time when scanning a predetermined angle range around the central axis, and the vertical axis represents the angle of the predetermined angle range,
Storage means for presetting and storing the speed pattern;
The X-ray imaging apparatus according to any one of claims 8 to 13, further comprising a reading unit that reads information on the speed pattern from the storage unit and provides the information to the control unit during the scan. . An elevator that rotatably supports the X-ray tube arm and the detector arm and provides an imaging space that allows the X-ray tube arm and the detector arm to rotate around the specific portion;
A pedestal part equipped with this elevator,
A shield formed of a shielding material that is positioned so as to define the imaging space and shields the X-ray;
The X-ray imaging apparatus according to claim 2, further comprising: The elevator includes a bottom surface part defining a part of the elevator, defining an edge on a bottom surface side of the imaging space,
The shield is
Left and right wall bodies arranged along the body axis direction of the subject when the specific part of the subject is located in the imaging space and located on both the left and right sides of the specific part, and the left and right wall bodies A first shielding body including a ceiling body that is integrally formed with and located above the specific part;
A second shield incorporated in the bottom surface;
The X-ray imaging apparatus according to claim 15, comprising: The X-ray imaging apparatus according to claim 16, wherein the first shield is configured to be slidable in the body axis direction with respect to the elevator. The X-ray imaging apparatus according to claim 16 or 17, wherein the ceiling portion of the first shield has a flat portion. The first shield is formed of a resin material containing lead,
The X-ray imaging apparatus according to claim 18, wherein the left and right wall bodies and the ceiling body are integrally formed. 19. The X-ray imaging apparatus according to claim 18, wherein the first shield partly has a translucent region that shields the X-ray and transmits light. 21. The X-ray imaging apparatus according to claim 20, wherein the translucent region is present at least in part or all of the flat portion. The elevator includes a back surface portion that defines a bottom edge of the imaging space and forms a part of the elevator,
The X-ray imaging apparatus according to any one of claims 16 to 21, wherein the shield includes a third shield positioned on the back surface portion. After the specific part of the subject is positioned in the imaging space, the shield substantially covers the front surface of the elevator which forms the front edge of the imaging space and shields the X-ray. The X-ray imaging apparatus according to any one of claims 16 to 22, further comprising a fourth shielding body to which the four shielding bodies can be detachably attached. The X-ray imaging apparatus according to any one of claims 15 to 23, further comprising moving means provided on the pedestal portion and capable of moving the entire apparatus. 25. The X-ray imaging apparatus according to claim 24, wherein the moving means includes a caster attached to the pedestal portion. The X-ray imaging apparatus moves to the back of the dental treatment chair, is positioned on the rear side of the dental treatment chair, and the head of the subject lying on the back on the dental treatment chair is the X-ray tube. An apparatus for performing X-ray imaging by positioning in an imaging space between the detector and
An operation unit operated by an operator;
A transmission means for transmitting an operation given to the operation unit;
Position specifying means for specifying a predetermined position when the X-ray imaging apparatus is laid on the chair;
A fixing means for locking the X-ray imaging apparatus at the predetermined position by locking the position specifying means according to the operation transmitted by the transmission means;
The X-ray imaging apparatus according to claim 2, further comprising: The position specifying means is a fixed frame fixed at the predetermined position on the floor close to the chair,
The fixing means includes a pin protruding in response to the operation transmitted by the transmission means, and a pin driving mechanism for driving the pin and locking the pin to the fixing frame.
27. The X-ray imaging apparatus according to claim 26. 28. The X-ray imaging apparatus according to claim 27, wherein a hole into which the pin is inserted is formed in the fixed frame. The operation unit is an operation lever that can be manually operated by an operator,
The operation lever can be operated in a step-by-step manner in order from the initial position when the operation lever is not operated and the operator from the initial position to the three-stage operation positions of the first stage and the second stage. It has a structure that takes two lever positions and can be returned in the reverse order,
The pin is urged by the operation of the operation lever from the initial position to the first-stage lever position and protrudes as a first stage, and the second-stage lever from the first-stage lever position. A positioning pin that is urged by the operation to a position and protrudes as a second stage;
The fixed frame has a long groove into which the pin protruding in the first stage is inserted, and a hole portion which is formed in the bottom surface of the long groove and into which the pin protruded in the second stage is inserted. The X-ray imaging apparatus according to claim 27. 30. The X-ray according to claim 29, wherein the positioning pin includes a plurality of pins, and is held so as to protrude downward from a lower portion of a front surface of the X-ray imaging apparatus by the pin driving mechanism. Shooting device. The fixing means includes a stop pin,
The fixed frame is oriented in a direction to allow the X-ray imaging apparatus to access the dental treatment chair in a state where the fixed frame is fixed to the floor, and the stop is received by the contact of the stop pin. Has a stopper surface to stop the forward movement of the pin
31. The X-ray imaging apparatus according to claim 29, wherein the hole is formed at a position continuous with a lower end of the stopper surface. 32. The X-ray imaging apparatus according to claim 31, wherein the positioning pins and the stopping pins are aligned in a horizontal line. The positioning pin and the stop pin are each composed of two pins,
The X-ray imaging apparatus according to claim 31 or 32, wherein the hole portion includes two hole portions that can be fitted into the two positioning pins, respectively. The X-ray imaging apparatus according to any one of claims 26 to 33, wherein the transmission means includes a wire that transmits an operation force of an operator applied to the operation lever to the pin driving mechanism. . An X-ray tube arm that rotatably holds the X-ray tube around a specific part of the subject;
A detector arm that rotatably holds the detector around the specific part;
An imaging space for rotatably holding the X-ray tube arm and the detector arm and allowing the X-ray tube arm and the detector arm to rotate around the imaging region of the subject is provided. An elevator to
A pedestal part equipped with this elevator,
A moving support means attached to the pedestal portion and movably supporting the device;
The X-ray imaging apparatus according to any one of claims 26 to 34, further comprising: 36. The X-ray imaging apparatus according to claim 35, further comprising a shielding body that is positioned so as to define the imaging space and is formed of a shielding material that shields the X-ray. An X-ray tube that emits X-rays;
An X-ray tube arm that rotatably holds the X-ray tube around a specific part of the subject;
A detector that detects the X-ray and outputs a signal corresponding to the amount of the X-ray;
A detector arm that rotatably holds the detector around the specific part;
An elevator that rotatably supports the X-ray tube arm and the detector arm and provides an imaging space that allows the X-ray tube arm and the detector arm to rotate around the specific portion;
A pedestal part equipped with this elevator,
A shield formed of a shielding material that is positioned so as to define the imaging space and shields the X-ray;
A portable X-ray imaging apparatus characterized by that. An X-ray tube that irradiates the subject's head positioned on the side of the dental treatment chair and lying on his back on the chair while irradiating X-rays while rotating around the head, and rotating around the head In a portable dental X-ray imaging apparatus provided with a detector that detects the X-ray transmitted through the head,
An operation unit operated by an operator;
A transmission means for transmitting an operation given to the operation unit;
Position specifying means for specifying a predetermined position when the X-ray imaging apparatus is laid on the chair;
A fixing means for locking the X-ray imaging apparatus at the predetermined position by locking the position specifying means according to the operation transmitted by the transmission means;
An X-ray imaging apparatus comprising:

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