Patent Description:
X-ray imaging is a method of radiography using the transmittance and straightness of X-rays, and differences in X-ray transmissivity according to an internal structure of an object to be imaged are displayed as an X-ray image in gray levels on the basis of X-ray attenuation accumulated during a process of transmitting through the object to be imaged.

An X-ray imaging apparatus is composed of necessary components including: an X-ray generator (hereinafter, referred to as a generator) configured to emit X-rays toward an object to be imaged; an X-ray detector (hereinafter referred to as a detector) configured to detect X-rays transmitting through the object to be imaged and generate X-ray projection data in which a relative difference between X-ray doses for each position is reflected; and an image processor configured to realize an X-ray image of the object to be imaged by using the X-ray projection data.

X-ray images may be classified in various ways. For example, X-ray panoramic images and Computed Tomography (CT) images of the dental arch are mainly used in the field of dentistry, where teeth and tissues surrounding the teeth are areas of interest.

An X-ray panoramic image shows a three-dimensional structure of the dental arch including upper and lower jaws spread out on a plane. The X-ray panoramic image is useful for fundamental diagnosis because of illustrating a comprehensive plan view of the three-dimensional structure of the dental arch. A CT image represents the three-dimensional structure of the dental arch as a three-dimensional voxel. The CT image may accurately express not only the three-dimensional structure of the dental arch, but also cross sections of desired positions and directions, so the CT image is useful in planning a high precision-required treatment such as an implant.

As the types of X-ray images are diversified, a so-called multimodality X-ray imaging apparatus capable of capturing different X-ray images with a single apparatus has been introduced and is widely used. For example, in dentistry, a combined X-ray panoramic and computed tomography (CT) X-ray imaging apparatus capable of capturing an X-ray panoramic image and a CT image with the single apparatus is used.

In a general combined panoramic and CT X-ray imaging apparatus, a patient's head, which is an examination object, is supported by an examination object support and aligned in an imaging position, a generator and a detector are arranged at opposite ends of a rotary arm, which is a predetermined mechanism, face each other with the examination object interposed therebetween, and the rotary arm rotates and/or moves about a rotation axis present therebetween to capture the X-ray panoramic image or CT image.

Meanwhile, imaging positions, that is, alignment positions of an examination object relative to the generator and detector are different from each other in the X-ray panoramic image and CT image. For this reason, the rotary arm is configured to be movable in the general combined panoramic and CT X-ray imaging apparatus, and the generator and detector move to respective imaging positions by the movement of the rotary arm during X-ray panoramic imaging and CT imaging.

However, separate mechanical components are required to move the rotary arm, thereby causing an increase in design and manufacturing costs. In addition, considering that the weight of the generator, detector, and rotary arm weighs quite a bit, the movement of the rotary arm substantially moves the center of gravity of the X-ray imaging apparatus, so another components are required to solve this issue, whereby there is a problem in that the apparatus is enlarged and complicated.

<CIT> refers to an X-ray CT scan with a variable distance between an X-ray generator and a rotation center and/or a variable distance between a X-ray detector and the rotation center. The respective distance can be changed according to a magnification of an image. The distance between the X-ray generator and the X-ray detector is constant, as both are fixed to a rotary device, such as a rotary arm. According to one embodiment the rotary device is movable by a mechanism X and Y directions, e.g. a XY table fixed on the top frame of the CT scanner. According to another embodiment, instead of the XY table as mechanism to move the rotary device another device for moving the object in X and Y directions is provided. In the described embodiment a chair for the patient to be scanned is movable by means of a first motor to move the chair in the Y direction and by means of a second motor to move the chair in the X direction. However, this known solution is comparatively complex and cost intensive.

An objective of the present disclosure is to solve the above problems. That is, the present disclosure relates to an X-ray imaging apparatus with the features of claim <NUM>. Further advantageous embodiments are presented in the dependent claims.

The present disclosure relates to the X-ray imaging apparatus capable of capturing the first and second X-ray images having imaging positions different from each other, and capable of moving and aligning the examination object to each imaging position without moving the rotary arm. Accordingly, there is an advantage in that the mechanical components for moving the rotary arm may be omitted or reduced, so that the apparatus may be miniaturized and simplified.

Hereinafter, a preferred exemplary embodiment of the present disclosure will be described with reference to the drawings.

<FIG> is a view illustrating an X-ray imaging apparatus according to the present disclosure. Hereinafter, a dental X-ray imaging apparatus will be described as an example for convenience, but the present disclosure is not limited thereto.

The X-ray imaging apparatus according to the present disclosure includes a main body <NUM>, an imaging part <NUM>, an examination object alignment part <NUM>, a driving controller <NUM>, and an image processor (not shown).

The main body <NUM> is configured to support the X-ray imaging apparatus according to the present disclosure, and includes a base <NUM> seated on a floor, a column <NUM> vertically connected to the base <NUM>, a lifting arm <NUM> connected to the column <NUM> to be movable up and down, and a support arm <NUM> vertically connected to the lifting arm <NUM>. However, the present disclosure is not limited thereto, and instead of omitting the base <NUM>, various modifications are possible such that the column <NUM> is directly fixed to the floor or mounted on a wall.

The imaging part <NUM> is configured to capture first and second X-ray images of an examination object, and includes: a rotary arm <NUM> connected to the support arm <NUM> by a rotation axis R; and a generator part <NUM> and a detector part <NUM> respectively arranged, to face with each other, at opposite ends of the rotary arm <NUM> provided with the rotation axis R interposed in between. The generator part <NUM> and the detector part <NUM> are respectively provided with a generator and a detector.

The examination object alignment part <NUM> is configured to align the examination object between the generator part <NUM> and the detector part <NUM>. In the X-ray imaging apparatus according to the present disclosure, instead of fixing a position of the rotation axis R of the rotary arm <NUM>, a position of at least a part of the examination object alignment part <NUM> is variable, so that the examination object is moved and aligned to each of a first alignment position for first X-ray imaging and a second alignment position for second X-ray imaging. The examination object alignment part <NUM> will be described in detail in corresponding sections.

The driving controller <NUM> is configured to control the first and second X-ray imaging by the imaging part <NUM>, and controls rotation of the rotary arm <NUM>, X-ray emission of the generator, and X-ray detection of the detector according to user's imaging signals. In particular, the driving controller <NUM> controls the imaging part <NUM> to capture the first X-ray image when the examination object alignment part <NUM> aligns the examination object at the first alignment position, and to capture the second X-ray image when the examination object alignment part <NUM> aligns the examination object at the second alignment position. In addition, the driving controller <NUM> may control various support operations for capturing the first and second X-ray images, such as adjusting the height of the lifting arm <NUM> relative to the column <NUM> according to user's operation signals.

The image processor reconstructs the first X-ray image by using first projection data obtained by the first X-ray imaging, and reconstructs the second X-ray image by using second projection data obtained by the second X-ray imaging. To this end, the image processor may include a computer and the like, on which a predetermined reconstruction algorithm is loaded, and for example, the first and second X-ray images may be respectively a CT image and an X-ray panoramic image.

<FIG> is a view illustrating the examination object alignment part of the X-ray imaging apparatus according to the present disclosure. Reference is made in conjunction with <FIG> described above.

The examination object alignment part <NUM> of the X-ray imaging apparatus according to the present disclosure includes: a frame <NUM> connected to the main body <NUM>; and an examination object support <NUM> configured to support an examination object and move along the frame <NUM>.

While providing a movement path for movement of the examination object support <NUM>, the frame <NUM> connects the main body <NUM> and the examination object support <NUM> to each other so as to support the examination object support <NUM>. The frame <NUM> may include: a base frame <NUM> configured to have one end thereof connected to the main body <NUM>, for example, to a lifting arm <NUM>; and a frame cover <NUM> configured to cover the base frame <NUM>.

The examination object support <NUM> is connected to the frame <NUM> to directly support the examination object, and moves in reciprocation between a first reference position for aligning the examination object to the first alignment position and a second reference position for aligning the examination object to the second alignment position. The examination object support <NUM> may include a base plate <NUM> and a plate cover <NUM> for covering the base plate <NUM>, and the plate cover <NUM> may be provided with a predetermined mechanism for supporting the examination object. For example, the mechanism may include: a chinrest <NUM> on which the examinee's chin is seated; and a bite <NUM> connected to the chinrest <NUM> and which the examinee, with his or her chin placed on the chinrest <NUM>, bites with his or her mouth.

Accordingly, when the examination object support <NUM> moves to the first reference position, the examination object is aligned to the first alignment position, and when the examination object support <NUM> moves to the second reference position, the examination object is aligned to the second alignment position.

In addition, the examination object alignment part <NUM> may include a handle <NUM> connected to a lower end of the frame <NUM> or examination object support <NUM> and gripped by the examinee's hand; a shelf <NUM> connected to the handle <NUM> and on which the examinee's accessories and the like may be placed; and the like.

<FIG> and <FIG> are views respectively illustrating internal structures of the examination object alignment part of the X-ray imaging apparatus according to the present disclosure. <FIG> is a view in which the frame cover <NUM> of the frame <NUM> and the plate cover <NUM> of the examination object support <NUM> are removed, and <FIG> is a view illustrating the plate cover <NUM> of the examination object support <NUM> with a hidden line.

The frame <NUM> includes a guide rail <NUM> installed on the base frame <NUM>, and the examination object support <NUM> includes a moving block <NUM> installed movably along the guide rail <NUM>. In addition, the plate cover <NUM> of the examination object support <NUM> may be fixed to the moving block <NUM> with a first screw S1 or the like. The base plate <NUM> may maintain a predetermined distance from the base frame <NUM> at the lower end of the base frame <NUM>, and may be fixed to the plate cover <NUM> with a second screw S2 or the like. The chinrest <NUM> may be fixed to the moving block <NUM>, and may be exposed to outside through the plate cover <NUM>.

Accordingly, when a user moves the examination object support <NUM> along a longitudinal direction of the guide rail <NUM>, the examination object support <NUM> including the moving block <NUM> may move along the frame <NUM>.

For example, the guide rail <NUM> may be installed along the longitudinal direction of the frame <NUM> at an end of the base frame <NUM>, and the examination object support <NUM> may move along the longitudinal direction of the frame <NUM> so that the degree of accommodation is adjusted while accommodating an end of the frame <NUM> therein. However, the present disclosure is not limited thereto, and it is also possible that the guide rail <NUM> is arranged at the end of the base frame <NUM> in a direction crossing the longitudinal direction of the frame <NUM> so that the examination object support <NUM> moves in the direction crossing the longitudinal direction of the frame <NUM> while accommodating the end of the frame <NUM> therein.

<FIG> is a view in which the moving block <NUM> and components coupled thereto in <FIG> are removed, and <FIG> and <FIG> are respectively a plan view and a bottom perspective view of the moving block <NUM>.

The moving block <NUM> may be coupled to a slider <NUM> movable along the guide rail <NUM>, so as to be movable along the guide rail <NUM>. In addition, the first and second stopper holders <NUM> and <NUM> configured to face with each other along the guide rail <NUM> installed on the base frame <NUM> and to be respectively provided with first and second grooves may be installed to be spaced apart from each other at a predetermined interval, and the first and second stopper protrusions <NUM> and <NUM> respectively press-fitted to the first and second stopper holders <NUM> and <NUM> may be respectively provided at front and rear ends in the movement direction of the moving block <NUM>. In addition, coupling positions of the first and second stopper holders <NUM> and <NUM> and coupling positions of the first and second stopper protrusions <NUM> and <NUM> may respectively correspond to the first reference position and the second reference position of the examination object support <NUM>.

Accordingly, when the examination object support <NUM> moves along the guide rail <NUM> in any one direction together with the moving block <NUM> so that the first stopper protrusion <NUM> is fitted to the first stopper holder <NUM>, the examination object support <NUM> is fixed to the first reference position, and when the examination object support <NUM> moves along the guide rail <NUM> in opposite direction of the one direction together with the moving block <NUM> so that the second stopper protrusion <NUM> is fitted to the second stopper holder <NUM>, the examination object support <NUM> is fixed to the second reference position. The first and second stopper holders <NUM> and <NUM> and the first and second stopper protrusions <NUM> and <NUM> are configured to fix the examination object support <NUM> to the respective first and second reference positions and at the same time are press-fitted to each other in order to prevent unnecessary movement of the examination object support <NUM> during X-ray imaging, and are easily separated from each other when the user applies force.

<FIG> and <FIG> are views respectively illustrating the moving states of the moving block <NUM> together with the driving controller <NUM>. <FIG> and <FIG> are referred together.

A sensing means <NUM> for detecting positions of the examination object support <NUM> may be provided in the examination object alignment part <NUM> of the X-ray imaging apparatus according to the present disclosure. In addition, according to detection results of the sensing means <NUM>, the driving controller <NUM> controls the imaging part <NUM> to capture the first X-ray image when the examination object support <NUM> is aligned at the first reference position and to capture the second X-ray image when the examination object support <NUM> is aligned at the second reference position.

The sensing means <NUM> may include: a guide pin <NUM> extending along the movement direction of the moving block <NUM> from one side of the moving block <NUM>; and a light source <NUM> and a light sensor <NUM> that are mounted on one side of the frame <NUM> and configured to face each other while having a point therebetween at which an end of the guide pin <NUM> selectively passes by the movement of the moving block <NUM>.

Accordingly, when the examination object support <NUM> moves to the first reference position in any one direction together with the moving block <NUM>, the end of the guide pin <NUM> deviates from the point between the light source <NUM> and the photosensor <NUM>, so that the photosensor <NUM> detects the light from the light source <NUM>, thereby outputting a first signal. In addition, when the examination object support <NUM> moves to the second reference position that is a reverse direction of the one direction together with the moving block <NUM>, the end of the guide pin <NUM> is inserted between the light source <NUM> and the light sensor <NUM> so as to block the light emitting from the light source <NUM> to the light sensor <NUM>, thereby outputting a second signal.

In addition, the first and second signals, which are the detection results of the sensing means <NUM>, are transmitted to the driving controller <NUM>, and according to the first and second signals, the driving controller <NUM> controls the imaging part <NUM> to capture the first X-ray image or the second X-ray image by detecting a state in which the examination object support <NUM> is aligned to any one of the first and second reference positions.

<FIG>are views respectively illustrating examination object positions provided by the examination object alignment part <NUM> during first and second X-ray imaging of the X-ray imaging apparatus according to the present disclosure. For convenience, it is assumed that the examination object support <NUM> moves along the longitudinal direction of the frame <NUM>.

<FIG> is a view illustrating the first X-ray imaging. The examination object support <NUM> moves in any one direction along the frame <NUM> to be positioned at the first reference position A1, and aligns the examination object to the first alignment position. The first alignment position is for the first X-ray imaging. For example, the first X-ray imaging may be CT imaging of the dental arch, and the first alignment position may be a position at which the rotation axis R coincides with the center of a field of view (FOV), which is a CT imaging area. For reference, the position and size of the FOV may be variously adjusted according to the examination object to be imaged during the CT imaging, and in this case, the center position of the FOV also varies. In addition, the examination object support <NUM> of the X-ray imaging apparatus according to the present disclosure moves, so as to allow the center R of the FOV to coincide with the rotation axis, whereby the first reference position A1 of the examination object support <NUM> may also vary depending on the position and size of the FOV. <FIG>represents a case where the dental arch is used as the FOV for convenience.

Claim 1:
An X-ray imaging apparatus configured to radiograph first and second X-ray images having examination object's alignment positions different from each other, the X-ray imaging apparatus comprising:
an imaging part (<NUM>) configured to comprise a generator and a detector facing each other with the examination object interposed therebetween, and rotate the generator and the detector about a rotation axis therebetween to radiograph each of the first and second X-ray images;
a main body (<NUM>) configured to support the imaging part; and
an examination object alignment part (<NUM>) configured to support the examination object between the generator and the detector,
wherein a position of at least a part of the examination object alignment part (<NUM>) is variable,
characterized in that
the examination object alignment part (<NUM>) further comprises:
a frame (<NUM>) connected to the main body (<NUM>); and
an examination object support (<NUM>) configured to support the examination object and move along the frame (<NUM>),
and in that the X-ray apparatus further comprises:
a guide rail (<NUM>) installed on the frame (<NUM>); and
first and second stopper holders (<NUM>, <NUM>) installed to be spaced apart from each other along the guide rail (<NUM>) to restrict respective movements of the examination object support (<NUM>),
wherein the examination object support (<NUM>) moves in reciprocation between a first reference position provided by the first stopper holder (<NUM>) and a second reference position provided by the second stopper holder (<NUM>) along the guiderail (<NUM>),
wherein the first reference position is a first alignment position for radiographing the first X-ray image and the second reference position is a second alignment position for radiographing the second X-ray image, respectively.