Patent Description:
X-ray radiographing is a radiation radiographing method using the penetrative characteristic of X-rays, and image information of an internal structure of the target is provided based on the accumulated extent of attenuation in a process of penetrating through the target. An X-ray radiographing apparatus for this include: an X-ray generator radiating X-rays, an X-ray sensor disposed to face the X-ray generator with a target interposed therebetween and detecting X-rays that have passed the target, and an image-processing device implementing an X-ray radiograph using the detection result of the X-ray sensor. Meanwhile, recently, due to developments in semiconductor and data processing technologies, X-ray radiographing has been rapidly replaced with Digital Radiography (DR) using a digital detector, and radiographing methods have been improved in various ways.

<FIG> shows a conventional dental X-ray radiographing apparatus.

The conventional dental X-ray radiographing apparatus includes a base supported by the floor, a column vertically standing from the base, and a lifter <NUM> vertically moving along the column in accordance with a height of the target. The lifter <NUM> is connected to a cantilever <NUM> at one side thereof. The cantilever <NUM> is connected to a rotary arm <NUM> at a lower part thereof so that the rotary arm <NUM> may rotate. The rotary arm <NUM> includes a generator <NUM> disposed on one side thereof with a rotation axis interposed therebetween, and an X-ray sensor <NUM> disposed opposite the generator <NUM> and opposite to the rotation axis. An examinee's head that includes a dental arch <NUM> of the examinee is fixedly disposed around a rotation axis 25C, and a position thereof may be adjusted depending on the area requiring examination.

A rotation driver <NUM> is provided to connect the rotary arm <NUM> and the cantilever <NUM> by being disposed therebetween, and to rotate the rotary arm <NUM> about the rotation axis 25C using driving power. The rotation driver <NUM> rotates the rotary arm <NUM> to a desired angle when radiographing a panoramic radiograph of the dental arch <NUM> of the examinee or when radiographing various X-ray radiographs to obtain a CT image.

Panoramic X-ray radiographs that are provided by using such a dental X-ray radiographing apparatus are used as the most familiar standard image to dentists since the overall arrangement relationship of teeth and surrounding tissues may be easily grasped from the images. X-ray CT radiographs may display a 3D image of the examinee and accurately and clearly display tomographic radiographs according to a user's desired position and direction, and thus X-ray radiographs have con to be utilized in fields requiring high precision, such as an implant procedure. Recently, in the field of orthodontics and the like, the utilization of the X-ray 3D radiographs is increasing.

In order to reconfigure panoramic X-ray radiographs, X-ray tomographic radiographs, or X-ray 3D radiographs, a dental X-ray radiographing apparatus requires a large number of x-ray transmission radiographs taken at various angles of the examinee. Therefore, a rotation amount of the rotary arm <NUM> for rotating the generator <NUM> and the X-ray sensor <NUM> increases, and a speed of rotation is also increased for rapid radiographing. However, operations during sequential X-ray radiographing cause the examinee to feel uneasy. Thus, motion artifacts may be generated. In addition, since the operation range of a radiographing apparatus is wide and the apparatus is not clearly distinguished from the surroundings, it is difficult to utilize the space.

A known solution for a X-ray imaging apparatus is shown in <CIT>. The X-ray imaging apparatus comprises an X-ray source which irradiates an object with X-rays; an image sensor which detects X-rays having passed through the object; a support arm <NUM> which supports the X-ray source and the image sensor; and a plurality of motors for moving the support arm. These motors move the X-ray source and image sensor along a CT image formation locus in the CT mode, and the X-ray source and the image sensor along a panoramic image formation locus in the case of the panorama mode.

Another solution for a device for generating a three-dimensional image of an object is disclosed in <CIT>, said device comprising a movable radiation source, a radiation detector, and an analyzing unit. The radiation source is moved relative to the object to be imaged into multiple positions in a first movement on a first track which lies on a first plane in order to capture images, at least one image being captured in each said position. The three-dimensional image is reconstructed from the captured images by the analyzing unit. The radiation source and the radiation detector carry out a second movement relative to the object to be imaged on a second track which is at least partly different from the first track at the same time as the first movement in order to reduce artifacts in the image, said artifacts being generated due to radiation absorption. In the process, the first movement and the second movement are superimposed.

An object of the present invention is to provide a dental X-ray radiographing apparatus including a radiographing housing that covers the whole radiographing unit including a generator, an X-ray sensor, and a rotary arm and provides a stable radiographing environment to an examinee.

Another object of the present invention is to provide a dental X-ray radiographing apparatus, while providing the radiographing housing, that minimizes a rotation range of the radiographing unit while ensuring a radiographing target area of a required size since there is a concern that the radiographing housing occupies an excessively large space in order to cover the maximum radius of rotation of the radiographing unit.

In addition, still another object of the present invention is to provide a dental X-ray radiographing apparatus in which the radiographing housing is quickly and conveniently moved to a corresponding position when an examinee is positioned for radiographing.

In addition, still another object of the present invention is to provide a dental X-ray radiographing apparatus capable of preventing a radiographing housing from being deflected or vibrated by allowing a load of the radiographing housing to be distributed and supported.

In order to accomplish the above object, according to the present invention, there is provided a dental X-ray radiographing apparatus with the features of claim <NUM>, the apparatus including: a radiographing unit including a X-ray generator and an X-ray sensor that rotate about a vertical rotation axis with a target interposed therebetween; and a radiographing housing being opened at a lower part thereof and being closed at an upper part thereof, and providing a radiographing space receiving the target therein and covering the radiographing unit.

The radiographing space according to the invention has a conical shape such that a width thereof increases along a downward.

The X-ray sensor may be inclined with respect to the rotation axis such that a distance between the X-ray sensor and the rotation axis increases along a downward. The X-ray sensor may move in a tangential direction of a rotation track centered on the rotation axis during X-ray radiographing.

The dental X-ray radiographing apparatus according to the present invention may further include: a lifter that vertically moves the radiographing unit and the radiographing housing upward and downward. In addition, the apparatus may further include: a handle frame disposed at a lower part of the radiographing housing with a height thereof being variable. Herein, the target is a head of an examinee, and the apparatus may further include: a chin rest disposed on the handle frame to support a chin of the examinee. A height of the radiographing unit relative to the chin rest during X-ray radiographing may be constant. In addition, the apparatus may further include: a displacement measuring unit measuring a height of the handle frame; and a controller controlling a vertical movement of the lifter according to the height of the handle frame. In addition, the apparatus may further include: a positioning guide disposed on the handle frame to support the target, and the positioning guide being the entirely or partially received inside the radiographing space during X-ray radiographing.

The dental X-ray radiographing apparatus according to the present invention may further include: a positioning guide disposed on the handle frame to support the target, and the positioning guide being the entirely or partially received inside the radiographing space during X-ray radiographing. In addition, the apparatus may further include: at least one camera installed in the radiographing housing and imaging the target.

The radiographing unit according to the invention includes a rotary arm connecting the X-ray generator and the X-ray sensor to each other, and rotating about the rotation axis. Herein, the dental X-ray radiographing apparatus according to the present invention further includes: a rotation support connecting the rotary arm and the radiographing housing. The rotation support may include a bearing disposed between the rotary arm and the radiographing housing. The rotation support may further include: a first bracket connected to the rotary arm and rotating therewith; and a second bracket connected to the radiographing housing with the bearing therebetween.

Meanwhile, in the dental X-ray radiographing apparatus according to the present invention, a radius of rotation of the X-ray sensor may be smaller than a radius of rotation of the X-ray generator.

According to the present invention, there is provided a radiographing housing that covers the whole radiographing unit including a generator, an X-ray sensor, and a rotary arm so that a stable radiographing environment may be provided to an examinee.

In addition, according to the present invention, there is provided a dental X-ray radiographing apparatus that has a radiographing housing with a compact size by ensuring a radiographing target area of a required size and by minimizing the rotation range of a radiographing unit.

In addition, the present invention provides a dental X-ray radiographing apparatus in which a radiographing housing is configured to quickly and conveniently move to a corresponding position when an examinee is positioned for radiographing.

In addition, the present invention may prevent a radiographing housing from being deflected or vibrated by allowing a load of the radiographing housing to be distributed and supported.

Hereinbelow, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments set forth herein are provided for illustrative purposes to fully convey the concept of the present invention. It will be apparent to a person skilled in the art that the present invention should not be construed to be limited to these embodiments. Throughout the drawings, the same reference numerals will refer to the same or like parts. Descriptions of some components depicted in a specific drawing will be omitted, when their reference numerals are identical to those of the components described with reference to another drawing.

<FIG> shows the exterior and a schematic configuration of an X-ray radiographing apparatus according to one embodiment of the present invention.

The X-ray radiographing apparatus according to the embodiment of the present invention includes a base frame <NUM> supported by being disposed on the floor, a lifter <NUM> installed to vertically move with a part thereof overlapping with the base frame <NUM>, and a radiographing housing <NUM> extending from the lifter <NUM> to an upper part of an examinee chair. A positioning guide <NUM> and a chin rest <NUM> that fasten and support an examinee's head are arranged below the radiographing housing <NUM>. The positioning guide <NUM> and the chin rest <NUM> are supported by a chin rest support <NUM>. The chin rest support <NUM> is a part of a handle frame <NUM> and is installed, for example, in an upper part of the handle frame <NUM>. A vertical column part <NUM> is provided in another part of the handle frame <NUM>, for example, in a lower part thereof, and the vertical column part <NUM> is inserted into a handle frame base <NUM> that is fixed with respect to the base frame <NUM>. The handle frame <NUM> may vertically move with respect to the handle frame base <NUM>. Preferably, the handle frame <NUM> is installed to horizontally rotate.

First, the radiographing housing <NUM> will be described. A radiographing unit <NUM> is installed inside the radiographing housing <NUM>. The radiographing unit <NUM> includes a rotation driver supported by an upper part of the radiographing housing <NUM>, a rotary arm, and a sensor unit and a generator unit that are disposed on both sides of the rotary arm. Detailed configurations thereof will be described later. The radiographing housing <NUM> forms an exterior that covers the outer surface of a rotation range of the radiographing unit <NUM>. In addition, the radiographing housing <NUM> covers an inner surface <NUM> of the rotation range of the radiographing unit <NUM> and provides a radiographing space into which a part or the entirety of the examinee's head is inserted during X-ray radiographing. At the same time, the radiographing housing <NUM> makes configuration components of the radiographing unit <NUM> invisible to the examinee. Accordingly, anxiety or reflexive movement of the examinee in response to the operation of the radiographing unit <NUM> may be prevented. As a result, motion artifacts in an X-ray radiograph may be prevented.

Herein, the inner surface <NUM> of the radiographing housing <NUM> of the X-ray radiographing apparatus according to the present embodiment may be parallel to an X-ray sensor, which will be described later. As a result, the distance between the inner surface <NUM> and the examinee's head increases along a direction from the top to the bottom. For example, the inner surface <NUM> may be inclined at a predetermined angle with respect to an imaginary vertical line so that a distance between the inner surface <NUM> and the imaginary vertical line increases along a downward direction. However, if the X-ray sensor is arranged parallel to a rotation axis of the radiographing unit, the radiographing housing <NUM> may include an inner surface that is perpendicular to the floor.

In addition, the X-ray radiographing apparatus according to the present embodiment may further include a number of cameras <NUM> that optically images an outside of an examinee's face from a lower part of the radiographing housing <NUM> and from an upper part of the handle frame <NUM>. Accordingly, X-ray radiographs obtained by X-ray radiographing and face images obtained using the number of cameras <NUM> may be provided. Meanwhile, the present embodiment includes a chair as shown in the figure. When the examinee sits on the chair, the height of the handle frame <NUM> is adjusted so that the examinee comfortably sits on the chair while putting his or hers chin on the chin rest <NUM> and biting a bite block <NUM>. Then, X-ray radiographing is performed when a part or the entire head of the examinee is inserted into the radiographing housing <NUM> by lowering the radiographing housing <NUM> including the radiographing unit <NUM> through the lifter <NUM>.

Herein, during X-ray radiographing, a height of the radiographing unit <NUM> relative to the handle frame <NUM>, more strictly relative to the chin rest <NUM>, may be maintained constant.

For this, heights of the handle frame <NUM> and the radiographing housing <NUM> may set by interlocking with each other. As one example of the above configuration, a displacement measuring unit <NUM> that measures height variation according to the vertical movement of the vertical column part <NUM> may be provided inside the handle frame base <NUM>. A potentiometer may be used for the displacement measuring unit <NUM>. The displacement measuring unit <NUM> is connected to a controller <NUM>, and the controller <NUM> is connected to an actuator <NUM> that vertically moves the lifter <NUM>. The actuator <NUM> may be guided, for example, by a driving shaft <NUM> so as to move therewith, and may adjust the height of the lifter <NUM> by using a driving guide <NUM> that receives a vertically moving force. The driving guide <NUM> is fixed to the lifter <NUM>.

As described above, the radiographing housing <NUM> may vertically move according to the operation of the lifter <NUM> before and after X-ray radiographing. As a result, although the height of the chin rest <NUM> varies according to the position of the examinee's head, the height of the radiographing unit <NUM> relative to the chin rest <NUM> is maintained constant during X-ray radiographing. In one embodiment, when the height of the head varies according to the height of the examinee, the chin rest <NUM> may be set at the position of the examinee's head by upwardly moving the handle frame <NUM>. Then, the lifter <NUM> may be controlled such that the height of the radiographing unit <NUM> relative to the chin rest <NUM> is maintained constant since the radiographing housing <NUM> downwardly moves for X-ray radiographing. Accordingly, although examinees have different heights, a part or the entire head of the examinee is always placed at a predetermined position inside the radiographing housing <NUM>. In addition, the radiographing housing <NUM> may not expose movements of configuration components that constitute the radiographing unit <NUM> to the examinee and to the outside. For this, the radiographing housing <NUM> includes an opaque casing for a closed top and perimeter thereof. In addition, the radiographing housing <NUM> may provide a cylindrical or conical radiographing space in which the examinee's head may be placed.

For reference, a dental X-ray radiographing apparatus according to the present invention may be configured without the chair, unlike the present invention, so that X-ray radiographing is performed while an examinee is standing. In the above case, the handle frame <NUM> may be disposed to match a given height while the examinee is standing.

<FIG> shows the configuration of an X-ray radiographing unit according to one embodiment of the present invention.

The radiographing unit 13T includes an rotation driver <NUM>, a rotary arm <NUM> rotating around a rotation axis 25C by the rotation driver <NUM>, an generator unit <NUM> arranged on one side of the rotary arm <NUM> and including an X-ray generator 321T and a collimator <NUM> to radiate collimated X-ray beams with a predetermined size, and a sensor unit 31T arranged on another side of the rotary arm <NUM> to face the generator unit <NUM> with a target interposed therebetween, and including a X-ray sensor that moves along the circumferential direction of the rotary arm <NUM> when the rotary arm <NUM> rotates, preferably along the tangential direction of a rotation track.

The X-ray generator 321T and the collimator <NUM> are installed such that a radiation direction of an X-ray beam, represented as a dotted line, forms a predetermined angle θB with respect to a surface that is perpendicular to the rotation axis 25C of the rotary arm <NUM> when viewed edge-on. The sensor unit 31T includes an X-ray sensor that is arranged to face the X-ray generator 321T and has a receiving surface which is inclined at a predetermined angle with respect to a surface that is parallel to the rotation axis 25C. Herein, a emitting direction of the generator is inclined from bottom to top with respect to the surface which is vertical to the rotation axis 25C. The predetermined angle θB may be <NUM>°<θB <<NUM>°. More preferably, the predetermined angle θB may satisfy <NUM>°<θB <<NUM>°. As a result, the sensor unit 31T is also downwardly inclined by an angle corresponding to θB with respect to the surface that is a virtual cylindrical outer circumferential surface around the rotation axis 25C and parallel to the rotation axis 25C. Accordingly, the sensor unit 31T has an angle θs of <NUM>°<θs<<NUM>° with respect to a surface in which rotary arm <NUM> is placed. More preferably, the sensor unit 31T may satisfy <NUM>°<θs <<NUM>°. It is preferable for a central axis between the sensor unit 31T and the X-ray beam, that is, a virtual line that connects the minimum distance from an emission point XF of the X-ray generator 321T to the sensor unit 31T, to be perpendicular to the sensor unit 31T when viewed edge-on.

Since the radiation direction of the X-ray beam is inclined from bottom to top and the sensor unit 31T is downwardly inclined, a radiographing space inside the radiographing housing <NUM> is formed to have a conical shape with a wider lower part, as shown in <FIG>. Thus, the examinee may place his or her head more conveniently.

Meanwhile, the present embodiment has a configuration in which a housing of the generator unit <NUM> is arranged to be perpendicular to the rotary arm <NUM> and the X-ray generator 321T is arranged to be inclined inside the housing. However, the generator unit <NUM> itself may be arranged to be inclined such that the generator unit <NUM> is approximately parallel to the sensor unit 31T.

The rotation driver <NUM> is connected to the lifter <NUM> and arranged inside of an upper part of the radiographing housing <NUM>, and a driving axis <NUM> thereof is connected to the rotation axis 25C of the rotary arm <NUM>. In one embodiment, the rotation driver <NUM> may include a direct operation motor known as a direct drive motor, and may be configured so that the center of the driving axis <NUM> matches the rotation axis 25C of the rotary arm <NUM>. Herein, power wirings and signal wirings around the driving axis <NUM> may be connected by using slip rings to prevent cables from being twisted. The slip rings may be wireless slip rings having wireless contacts.

<FIG> shows the principle in which a rotation range of the radiographing unit is reduced on the assumption that the same size of radiographing target space is provided by a configuration of the radiographing unit according to a second embodiment of <FIG>.

<FIG> shows the case similar to the conventional art, in which a radiation direction of an X-ray beam is parallel to a surface that is perpendicular to a rotation axis 25C, so that a sensor unit 31V is parallel to the rotation axis 25C, and <FIG> shows the case where the sensor unit 31T and the radiation direction of the X-ray beam are inclined as described with reference to <FIG> according to the present invention.

Herein, the height H of a radiographing examinee is the same in <FIG>. In <FIG>, an X-ray beam is obliquely radiated and the sensor unit 31T is installed to be inclined, thus an emission point XF of the X-ray beam is positioned relatively closer to the rotation axis 25C than an emission point XV of <FIG>. This means that a rotation range of the radiographing unit may be narrowed by a difference in distance between the two emission points XF and XV. Accordingly, a space occupied by an X-ray radiographing unit may be reduced, and more directly, the size of the radiographing unit described above may be reduced.

<FIG> shows a configuration that provides a wide radiographing target space provided by an X-ray sensor of the radiographing unit of the X-ray radiographing apparatus according to one embodiment of the present invention.

The present figure schematically shows the configuration of the radiographing unit of the X-ray radiographing apparatus, and is a schematic representation of the rotation axis 25C of the rotary arm <NUM> as viewed from above. The radiographing unit receives a control signal from the controller <NUM> and performs X-ray CT radiographing sequences. While performing X-ray CT radiographing sequences, the radiographing unit rotates a radiation path of an X-ray beam that passes a part of a target, and at the same time, moves a virtual X-ray beam center such that the X-ray beam is radiated at various angles over a predetermined range with respect to all parts within a radiographing target area.

A sensor unit <NUM> includes an X-ray sensor <NUM> oriented toward the generator unit <NUM>. Herein, assuming that the height and the width of the entire area of the radiographing target area to obtain the CT image thereof are t1 and w1, respectively, the height t2 of the X-ray sensor is equal to or greater than magnification*first height t1 ( (t2≥ magnification * t1), and the width w2 of the X-ray sensor is less than magnification*first wide w1/<NUM> (w2< magnification *w1/<NUM>). As reference, the height of the X-ray sensor may be adjusted according to the purpose. Based on a dental x-ray apparatus, in one embodiment, the width of the X-ray sensor may be <NUM>~<NUM>. In addition, the X-ray sensor <NUM> may move along a rotation track of the sensor unit <NUM> centered on the rotation axis 25C, for example, along a tangential direction of a circular trajectory. The generator unit <NUM> emits an X-ray beam XC aimed on the X-ray sensor <NUM> by interlocking with the movement of the X-ray sensor <NUM>.

In the present figure, concentric circles F, FA, FB, and FC which are centered on the rotation axis 25C indicate the expansion of the radiographing target area according to the movement of the X-ray sensor <NUM>. For example, when the X-ray sensor <NUM> is fixed on an initial position that is shown with the solid line and rotates over a predetermined angle, for example, <NUM> degree, an X-ray CT radiograph of the smallest radiographing target area FF may be obtained. This is substantially similar to a conventional half-beam x-ray radiographing apparatus. In addition, when an X-ray sensor <NUM> moves in the tangential direction by, for example, a width 311A from the position indicated by the solid line while performing successive X-ray radiographing accompanied by additional rotation centered on the rotation axis 25C, the radius of the radiographing target area FA is extended by the width 311A of the X-ray sensor <NUM>. Similarly, when the X-ray sensor <NUM> moves by twice the width 311B and moves by three times the width 311C during successive radiographing, the radiographing target areas FB and FC are also expanded with the increase of the moving range. Therefore, the width of the X-ray sensor <NUM> is smaller than a value obtained by multiplying the radius of the extended actual radiographing target areas FA, FB, and FC by the maximum enlargement ratio.

As reference, in the above description, the X-ray sensor <NUM> is described as gradually moving according to a rotation cycle centered on the rotation axis 25C for convenience of explanation. Preferably, the X-ray sensor <NUM> may simultaneously move and rotate centered on the rotation axis 25C. The above process will be described hereinafter.

In terms of a device configuration, the sensor unit <NUM> includes an X-ray sensor driver <NUM> that moves the X-ray sensor <NUM> in the tangential direction of its rotation track within a limited range. The X-ray sensor driver <NUM> may include, for example, a motor <NUM> that generates driving power, a driving shaft <NUM> that transfers the generated driving power, and a connector <NUM> connecting a part of the X-ray sensor <NUM> and the driving shaft <NUM>. However, such a mechanical configuration is merely an example, and it may be implemented in various forms.

Meanwhile, the generator unit <NUM> radiates an aimed X-ray beam XC on the X-ray sensor <NUM> by interlocking with the positional movement of the X-ray sensor <NUM>, and has a width capable of covering the width of the X-ray sensor <NUM>. As an example configuration for this, the generator unit <NUM> may include an X-ray generator <NUM> that emits an X-ray beam XT with a wide-width covering the moving range of the X-ray sensor <NUM>, and a collimator <NUM> that emits an X-ray beam XC focused on the X-ray sensor <NUM> according to the position of the X-ray sensor <NUM> and having a narrow width associated with the X-ray sensor <NUM> by adjusting the wide-width X-ray beam XT. The collimator <NUM> may include at least one blade <NUM> that partially blocks the X-ray beam, a motor <NUM> that generates driving power to move the at least one blade <NUM>, a driving shaft <NUM> that transfers the generated driving power, and a connector <NUM> that connects the blade <NUM> and a part of the driving shaft <NUM>. The collimator <NUM> may drive a single blade that includes a slot with a predetermined width, and passes the focused X-ray beam XC by using a single motor, or may drive at least two blades by using respective motors.

However, the configuration of the generator unit <NUM> described above is merely an example, and may be implemented in various forms. For example, the generator unit <NUM> may include X-ray generator that emits an X-ray beam having a narrow width corresponding to the X-ray sensor <NUM>, and adjusts the radiation direction of the X-ray beam emitted from the X-ray generator by interlocking with the positional movement of the X-ray sensor <NUM>. Thus, a focused X-ray beam is emitted. Various other configurations are possible.

Meanwhile, the X-ray radiographing unit according to the embodiment described above may further include a controller <NUM> that is connected to the generator unit <NUM> and the sensor unit <NUM>, and controls the same such that the generator unit <NUM> emits an X-ray beam XC that is focused on the X-ray sensor <NUM> by interlocking with the positional movement of the X-ray sensor <NUM>. In detail, the controller <NUM> is connected to the X-ray sensor driver <NUM> to control the motor <NUM>, and controls the direction of the X-ray beam that is emitted from the generator unit <NUM> by using a control signal of the motor <NUM> or a feedback reception signal of positional information of the X-ray sensor <NUM>. The direction of the X-ray beam may be controlled by controlling the motor <NUM> that drives the collimator <NUM> as shown in the figure of the embodiment. However, as described above, when the generator unit <NUM> is implemented in a different form, the specific object that receives the control signal of the controller <NUM> may vary.

The present figure is the representation of the rotation axis 25C as viewed from above, and does not show vertical tilting of the sensor unit <NUM> or the X-ray generator <NUM>. However, the sensor unit <NUM> and the X-ray generator <NUM> may be arranged to be inclined with respect to the rotation axis 25C as the sensor unit 31T and the X-ray generator 321T shown in <FIG>. This feature will be the same in the following drawings.

<FIG> shows the principle of radiographing a part of the radiographing target area by the radiographing unit of the X-ray radiographing apparatus according to one embodiment of the present invention.

By using the X-ray radiographing unit of the embodiment of the present invention described with reference to <FIG>, a radiographing target area described above is expanded, and a position of the radiographing target area may be freely selected and radiographed within the available range of the sensor <NUM>. Of course, the position may be expanded by moving the sensor <NUM> based on the selected position.

The present figure shows wide-width X-ray beams XT, XTD, and XTE at some points 32D and 32E on a track along which the generator unit <NUM> passes, focused narrow X-ray beams XC, XCD, and XCE, and a radiographing target area FF formed at a position at which the X-ray beams overlap each other during radiographing by rotating the sensor unit including the generator unit <NUM> and the sensor <NUM> around the rotation axis 25C. When the generator unit <NUM> is positioned in some points 32D and 32E described above, the sensor <NUM> may receive the aimed X-ray beams XC, XCD, and XCE by moving to the associated points 32D and 32E within the radiation ranges of the wide-width X-ray beams XT, XTD, and XTE.

<FIG> shows an example of an atypical radiographing target space that may be radiographed by the X-ray radiographing apparatus according to one embodiment of the present invention.

As shown in the figure, the shape of the radiographing target area FT is not limited to a cylindrical shape or the like. Free-form atypical radiographing target areas may be radiographed when the areas are expressed as formulas. The radiographing target area may be input using an input means before X-ray CT radiographing. However, various radiographing target areas corresponding to a plurality of clinically frequently utilized anatomical regions may be stored in advance and displayed to a user, and the user may perform input by selecting one of them.

<FIG> shows the situation where a panoramic radiograph is radiographed by using the X-ray radiographing apparatus according to one embodiment of the present invention.

As shown in the figure, it is possible to obtain the same effect as moving a rotation axis in a conventional panoramic X-ray radiographing apparatus without actually moving the rotation axis 25C by rotating a sensor unit including the generator unit <NUM> and the sensor <NUM> and by moving a position of the sensor <NUM> to the tangential direction of the rotation track thereof. Accordingly, with the X-ray radiographing apparatus according to the present invention, X-ray CT radiographs, 3D radiographs, and panoramic X-ray radiographs for a focus layer corresponding to a dental arch <NUM> may be provided using such features.

<FIG> schematically shows the inside of a radiographing housing of a dental X-ray radiographing apparatus according to one embodiment of the present invention.

As shown in the figure, the X-ray radiographing apparatus according to one embodiment of the present invention includes a radiographing housing <NUM> that accommodates a radiographing unit <NUM>. The radiographing housing <NUM> includes an X-ray generator <NUM> and an X-ray sensor <NUM> that are respectively arranged on both sides thereof, and covers a rotation area of a rotary arm <NUM> that is supported by a cantilever <NUM> so that the rotary arm <NUM> rotates around a rotation axis. A rotation driver <NUM> that makes the rotary arm <NUM> rotate with respect to the cantilever <NUM> may be installed in the cantilever <NUM> or inside the rotary arm <NUM>.

The radiographing housing <NUM> is arranged below the rotary arm <NUM>, and includes a radiographing housing lower casing <NUM> in which an inner diameter R1 thereof is smaller than a radius of rotation of the X-ray sensor <NUM> having a relatively small turning radius. The radiographing housing <NUM> may include various parts such as a radiographing housing lower casing <NUM>, described above, and an upper casing in which an outer diameter R2 thereof is larger than the radius of rotation of the X-ray generator <NUM> and which covers the remaining parts. There is no restriction on a boundary position between the upper casing and the lower casing <NUM>.

The radiographing housing <NUM> may be configured with a plastic structure such as ABS resin, carbon resin, etc. Since the size thereof is large and rotating components are provided therein, deformation such as deflection or vibration may occur. A part of the radiographing housing <NUM> lying on an upper part of the rotary arm <NUM> is supported by the cantilever <NUM>, which is a fixed structure to support a load of the part, or may be supported by being connected to another fixed structure that is not shown, such as column. However, since the radiographing housing lower casing <NUM> that is positioned in a lower part of the rotary arm <NUM> is far from the fixed structure such as the cantilever <NUM>, an elastic deflection or a permanent deflection caused by a creep may occur. In order to reinforce the structural rigidity and prevent the deflection thereof, the size and the self-load of the radiographing housing <NUM> may be increased.

According to the embodiment of the present invention, by using a rotation support <NUM> that is installed between a lower part of a rotation axis of the rotary arm <NUM> and the lower casing <NUM> of the radiographing housing <NUM>, at least a part of a load of the radiographing housing <NUM>, which is a non-rotating structure, may be supported by the rotary arm <NUM>, which is a rotating structure. The load of the radiographing housing <NUM> transferred to the rotary arm <NUM> is transferred to the cantilever <NUM>, and the load is supported by the cantilever <NUM> with the load of the rotary arm <NUM> itself. In other words, the rotation support <NUM> is connected to the lower part of the rotation axis of the rotary arm <NUM>, which is a rotating structure, on one side thereof, and is connected to the lower casing <NUM> of the radiographing housing <NUM> on another side thereof. Thus, the rotary arm <NUM> may freely rotate while supporting a load in the axial direction of the radiographing housing <NUM>. For this, the rotation support <NUM> may include a bearing disposed between the rotary arm <NUM> and the radiographing housing <NUM>.

<FIG> shows an example of a rotation support disposed between the rotary arm and the radiographing housing of the embodiment of <FIG>.

As shown in the figure, in one embodiment, the rotation support <NUM> may include a first bracket <NUM> that is installed in an lower part of the rotation axis of the rotary arm <NUM> and rotates with the rotary arm <NUM>, a second bracket <NUM> that is installed inside the radiographing housing <NUM> close to the first bracket <NUM>, and a bearing <NUM> that is installed between the first bracket <NUM> and the second bracket <NUM> so that the load of the radiographing housing <NUM>, which is a non-rotating structure, is supported by the rotary arm <NUM>, which is a rotating structure. Referring to the present figure, a part of the load of the radiographing housing <NUM>, particularly, a load of a part including the lower casing <NUM> is transferred to an inner race of the bearing <NUM> through the second bracket <NUM>, and then the load is transferred to an outer race of the bearing <NUM> through an inside of the bearing <NUM> such as ball, etc., and the load is then transferred to the rotary arm casing 430C through the first bracket <NUM>. Herein, the load is transferred to the rotary arm casing 430C, but the load may be transferred to the frame structure of the rotary arm.

Herein, the bearing <NUM> may be selected from various types of bearings such as a ball bearing, a roller bearing, a radial bearing, a thrust bearing, etc. In one embodiment, an angular ball bearing may be selected for the bearing <NUM> such that the rotary arm <NUM> supports the load of the radiographing housing <NUM> due to gravity, and a load in a direction perpendicular to an axis.

<FIG> shows another example of the rotation support of the embodiment of <FIG>.

The rotation supports 35a and 35b that are shown in the present figure are the same as the rotation support <NUM> shown in <FIG> except for bearings 355a and 355b. <FIG> shows an example of selecting a thrust ball bearing for the bearing 355a of the rotation support 35a, and the example is focused on supporting a strong axial load. <FIG> shows an example of selecting a taper roller bearing for the bearing 355b of the rotation support 35b, the example is focused on supporting both a load in the axial direction and a load in the direction perpendicular to the axis, as in the example of <FIG>. Accordingly, when a bearing that supports loads other than the axial direction is selected, it is advantageous to prevent deformation and vibration of the radiographing housing even in the case of abnormal shocks in a direction different from gravity such as when a body part of the examinee hits the radiographing housing.

Claim 1:
A dental X-ray radiographing apparatus, the apparatus comprising:
a radiographing unit (<NUM>) including a rotary arm (<NUM>), an X-ray generator arranged on one side of the rotary arm (<NUM>) and an X-ray sensor arranged on the other side of the rotary arm (<NUM>) ;
a rotation driver adapted for rotating the rotary arm (<NUM>) about a vertical rotation axis and a target interposed between the X-ray generator and the X-ray sensor; wherein the target is a head of an examinee; and
a radiographing housing (<NUM>) providing a radiographing space adapted for receiving a part or entirety of the target and covering the radiographing unit (<NUM>),
wherein the radiographing housing (<NUM>) includes:
a lower part configured to be opened in order to provide the radiographing space; and
an upper part configured to be closed in order to make configuration components of the radiographing unit (<NUM>) invisible to the examinee,
characterized in that
the radiographing housing (<NUM>) is a non-rotating structure and covers an inner surface of the rotation range of the radiographing unit (<NUM>); and
the radiographing space has a conical shape such that a width thereof increases along a downward direction.