KR20160030665A - Apparatus and method for reconstructing x-ray image - Google Patents

Abstract

An apparatus and method for reconstructing an image corresponding to a different position from an image of a subject imaged with a single position are disclosed. An apparatus for reconstructing an image from an image of a subject using X-rays, the apparatus comprising: an image reconstruction device for generating an X-ray image of a position 1 based on an X-ray passing through the subject under pressure in accordance with the position 1; A distortion model estimating unit for estimating an attenuation coefficient in the three-dimensional space from the photographed images of the position 1, a distortion model corresponding to the position 1, and a position 2 And an image synthesis unit for synthesizing the X-ray photographed image of position 2 from the attenuation coefficient based on the deformation model corresponding to the deformation model.

Description

[0001] APPARATUS AND METHOD FOR RECONSTRUCTING X-RAY IMAGE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a technique for generating an image by irradiating an X-ray while a breast being inspected is being pressed, and more specifically, And reconstructing the corresponding image.

An X-ray imaging apparatus radiates X-rays to a subject such as a chest (breast), acquires an image from X-rays passing through the subject, and is able to grasp the lesion existing in the subject.

In such an X-ray imaging apparatus, X-rays are irradiated in the state of being pressed while the breast is being imaged, and inward and outward oblique photography (hereinafter referred to as MLO imaging) and up and down imaging (hereinafter referred to as CC imaging) are mainly used.

MLO is a technique for irradiating X-rays while the breast is pressed in a diagonal direction, and CC photography is a technique for irradiating X-rays while the breast is being pressed in a vertical direction. Thus, as MLO and CC shots taken at different compression positions are used during mammography, the breast is pressed at least twice in a different posture. As a result, the pain and the inconvenience due to the pressing are increased.

Therefore, even if the subject does not press the breast several times, a technique capable of acquiring both the MLO image and the CC image while being pressed in a single posture is required.

Embodiments of the present invention are for reconstructing an image corresponding to a pressed state at another position from an image photographed in a state of being pressed in one position so as not to press the subject multiple times.

An apparatus for reconstructing an image from an image of a subject using X-rays of the present invention includes an image generating unit for generating an X-ray image of a position 1 based on an X-ray passing through a subject pressed under position 1 A distortion model estimating section for estimating an attenuation coefficient on the three-dimensional space from the photographed images of the position 1, and a distortion model estimating section for estimating a distortion model corresponding to the position 1 and a position 2 And an image synthesizing unit for synthesizing the X-ray image of the position 2 from the attenuation coefficient based on the deformation model corresponding to the deformation model.

According to an aspect, the image synthesizing unit may synthesize the X-ray image of the position 2 based on the damping coefficient in a state where the subject is pressed in accordance with the position 1.

According to another aspect, the X-ray image of the position 1 is any one of an inner and outer oblique direction photographing (MLO) image and a vertical direction photographing (CC) image, and the X- (MLO) image and the up-and-down-direction (CC) image, except for the X-ray image of the position 1.

According to another aspect, the deformation model corresponding to the position 1 may include a geometric position corresponding to each of the pressed tissues constituting the subject when the subject is pressed in the inward and outward directions.

According to another aspect of the present invention, the image synthesizing unit synthesizes a geometric position matching the geometrical position of each tissue included in the deformation model corresponding to the position 1, based on an affine transformation, And the X-ray image of the position 2 can be synthesized by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position.

According to another aspect of the present invention, the image generating unit may adjust the projection dose of at least one of the X-ray images taken at the position 1 to adjust the sharpness of the X-ray image of the position 1. According to another aspect of the present invention, the image combining unit may be configured to match the geometric position of each tissue included in the deformation model corresponding to the position 1, based on the anatomical information estimated from the attenuation coefficient of each point in the three- The geometric position is determined from the deformation model corresponding to the position 2, and the X-ray image of the position 2 is synthesized by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position .

An image reconstruction method performed by an apparatus for reconstructing an image from an image of a subject using X-rays of the present invention is an image reconstruction method for reconstructing an X-ray image of a subject 1 based on an X- Estimating an attenuation coefficient on the three-dimensional space from the photographed images of the position 1, and estimating an attenuation coefficient on the basis of the deformation model corresponding to the position 1 and the position where the subject is pressed in a different posture from the position 1 And synthesizing an X-ray image of position 2 from the attenuation coefficient based on the deformation model corresponding to the position of the position 2.

According to an aspect of the present invention, in the step of synthesizing the X-ray image of the position 2, the X-ray image of the position 2 can be synthesized based on the attenuation coefficient in a state where the subject is pressed in accordance with the position 1 have.

According to another aspect, the X-ray image of the position 1 is one of an inner and outer oblique direction (MLO) image and a vertical direction (CC) image, and the X- (MLO) image and the up-and-down-direction (CC) image, except for the X-ray image of the position 1.

According to another aspect, the deformation model corresponding to the position 1 may include a geometric position corresponding to each of the pressed tissues constituting the subject when the subject is pressed in the inward and outward directions.

According to another aspect, the step of reconstructing the X-ray image of the position 2 includes a step of reconstructing an X-ray image of the position 2 based on an affine transformation, and a geometric step of matching the geometric position of each tissue included in the deformation model corresponding to the position 1, Determining a position from the deformation model corresponding to the position 2, and reconstructing the X-ray image of the position 2 by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position . ≪ / RTI >

According to another aspect of the present invention, the step of synthesizing the X-ray image of the position 2 includes incorporating the X-ray image into the deformation model corresponding to the position 1 based on the anatomical information estimated from the attenuation coefficient of each point in the three- Determining a geometric position corresponding to a geometric position of each tissue from the deformation model corresponding to the position 2 and mapping the geometric position corresponding to the geometrical position of each tissue to the matched geometric position, 2 of the X-ray image.

According to another aspect of the present invention, the step of generating the X-ray image of the position 1 includes adjusting a projection dose of at least one of the X-ray images taken at the position 1, The sharpness of the photographed image can be adjusted.

According to another aspect, the X-ray image of the position 1 is a tomosynthesis image photographed by MLO, and the X-ray image of the position 2 is an X- And a synthetic mammo image obtained by synthesizing the tomosynthesized image.

According to the present invention, as the image corresponding to the different position is reconstructed from the image captured in a state in which the subject is pressed in one position, it is not necessary to press the breast for each position, and the number of times the breast is pressed Or minimized.

1 is a perspective view illustrating an image reconstruction system according to an embodiment of the present invention.
2 is a block diagram illustrating a detailed configuration of an image reconstruction apparatus according to an embodiment of the present invention.
3 is an exemplary diagram illustrating a deformation model of position 1 and a deformation model of position 2 according to an embodiment of the present invention.
4 is a flowchart illustrating an image reconstruction method according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the embodiments. In addition, the same reference numerals shown in the drawings denote the same members.

1 is a perspective view illustrating an image reconstruction system according to an embodiment of the present invention. The image reconstruction apparatus described in this specification can be applied variously such as Cone-Bean Computed Tomography (CBCT), Mammography, Tomography, Tomosynthesis, and the like.

1, the image reconstruction system 100 includes an X-ray imaging apparatus 110 for radiating X-rays to an object to be inspected such as a breast and an X- And an image reconstruction device 120 that receives the information related to the line and generates an X-ray photographed image.

First, the X-ray imaging apparatus 110 includes a tube 111 for irradiating an X-ray to a subject such as a breast, a main body 112 for rotating the subject around the subject in accordance with a predetermined rotation angle, An X-ray detecting section 113 for detecting an X-ray, and a pressing section 114 for pressing the breast. Here, the tube 111 irradiates the subject with a plurality of X-rays, and the number of the tubes 111 may be one or more. Unlike the X-ray detecting unit 113 and the pressing unit 114, the tube 111 can rotate independently.

The image reconstruction apparatus 120 can generate an X-ray image based on the X-rays transmitted through the object to be inspected transmitted from the X-ray imaging apparatus 110. For example, the image reconstruction apparatus 120 may generate an X-ray image of position 1 based on X-rays transmitted through the breast in a state in which the breast is pressed in position 1.

Then, the image reconstruction apparatus 120 can reconstruct the X-ray image corresponding to the position 2 from the X-ray image of the position 1. Here, position 1 indicates the posture in which the breast is pressed in the diagonal direction for MLO imaging, and position 2 indicates the posture in which the breast is pressed in the vertical direction for CC imaging.

For example, the image reconstruction apparatus 120 reconstructs the CC image corresponding to the position 2 from the MLO image photographed while the breast is pressed in accordance with the position 1 even if the subject does not change the posture from the position 1 to the position 2 . In other words, if the breast is pressed only once for MLO imaging, the image reconstruction device 120 can reconstruct the CC image from the MLO image, even if it is not pressed back to a different posture for CC imaging.

In addition, the image reconstruction apparatus 120 may reconstruct the MLO image and the ML image from the CC image, or may reconstruct the ML image and the like from the MLO image.

1, the X-ray imaging apparatus 110 can perform X-ray imaging while the patient is standing and pressing the breast between the pressing section 114 and the X-ray detecting section 113. [ In this case, the external structure of the X-ray imaging apparatus 110 is not limited to that shown in Fig. 1, and may have an external structure in which the patient can sit or lie down and take a picture.

The image reconstruction apparatus 120 may be a workstation or the like, and the X-ray image may include a 3D X-ray image, a 2D X-ray image, and the like. In this case, the image reconstruction apparatus 120 may be connected to the X-ray imaging apparatus 110 in a wired or wireless manner.

2 is a block diagram illustrating a detailed configuration of an image reconstruction apparatus according to an embodiment of the present invention.

2, the image reconstruction apparatus 200 may include an information receiving unit 201, an image generating unit 202, a damping coefficient estimating unit 203, and an image synthesizing unit 204.

The information receiving unit 201 can receive the X-rays transmitted from the X-ray photographing apparatus 210 through the subject. For example, the information receiving unit 201 can receive X-rays that have passed through the breast while the breast is being pressed in the oblique direction. In other words, the X-ray imaging apparatus 210 may perform MLO imaging according to position 1, and may transmit the X-ray passing through the breast to the information receiving unit 201.

The image generating unit 202 can generate the X-ray image of the position 1 using the image reconstruction algorithm based on the X-ray passing through the subject under the pressure of the position 1.

For example, the image generating unit 202 may generate the MLO image based on the X-rays that have passed through the breast while the breast is pressed in the oblique direction. In addition, the image generating unit 202 generates the CC image based on the X-ray passing through the breast in the state where the breast is pressed in the vertical direction, the ML image based on the X- And so on.

In this case, when the mammogram is taken using the tomosynthesis technique in the X-ray imaging apparatus 210, the image generating unit 202 may generate a synthesized MLO image, a CC image, an ML image, and the like. When the breast is photographed using the tomosynthesis technique in the X-ray imaging apparatus 210, the image generation unit 202 may generate tomosynthesis MLO images, CC images, ML images, and the like.

The attenuation coefficient estimating unit 203

The image synthesizing unit 204 can reconstruct the X-ray image of the position 2 which is pressed in a different posture from the position 1 from the X-ray image of the position 1. [ In other words, the image synthesizing unit 204 can reconstruct the X-ray image of the position 2 from the X-ray image of the position 1 even if the subject does not actually take the posture of the position 2.

At this time, the image synthesis unit 204 reconstructs the X-ray image of the position 2 from the X-ray image of the position 1 based on the deformation model corresponding to the position 1 and the deformation model corresponding to the position 2, can do.

Here, the deformation model represents the geometrical position of each tissue constituting the breast during breast compression, and the geometric position of the tissue may be changed by position after compression by the tissue in the same geometric position before compression. As such, you can have different deformation models for each position. In other words, the deformation model of the position 1 is different from the deformation model of the position 2, and a detailed description of reconstructing the X-ray image of the position 2 using the deformation model will be described later with reference to FIG.

On the other hand, the image generating unit 202 can adjust the sharpness of the X-ray image of the position 1 by adjusting the projection dose of at least one of the plurality of X-ray images taken at the position 1 .

. For example, the image generating unit 202 may increase the sharpness by increasing the dose of the projection one or more times according to the preset dose adjustment value. At this time, the dose of the projections in only one direction may be adjusted, the dose of the projections in two or more directions may be adjusted, or the dose after conversion may be adjusted only. Further, the dose of projection in one direction, in two or more directions, and after conversion may all be adjusted.

3 is an exemplary diagram illustrating a deformation model of position 1 and a deformation model of position 2 according to an embodiment of the present invention.

The image reconstruction apparatus and the X-ray imaging apparatus described with reference to FIG. 3 are the same as those of the image reconstruction apparatus and the X-ray imaging apparatus of FIG. 2, and a duplicate description will be omitted.

In Fig. 3, the arrow direction 306 passing between the first and third times of the pressed breast may correspond to the CC photographing direction. At this time, the image generating unit 202 increases the sharpness, that is, the quality of the synthetic mammography image, by increasing the dose in two directions in the arrow direction 306 and the MLO direction.

3, the MLO image is an image photographed in a state in which the breast 303 is pressed in a diagonal direction, that is, an inner / outer direction 302, and a deformation model 304 of the MLO image is a breast, And the geometric position of the breast tissue as a result of this pressure.

For example, when the breast 303 is pressed in the inward and outward directions 302, the breast tissue 205 located between 1 and 2 before the press is between 1 and 2 after compression, Can be located at the bottom.

The CC image is an image captured while the breast 312 is pressed in the upward direction 311 and the deformation model 313 of the CC image can indicate the geometric position of the breast tissue as the breast is pressed with the position 2 .

For example, when the breast 312 is pushed in the up and down directions 311, the breast tissue 314 located between 1 and 2 before the press is between 1 and 2 after the compression, Lt; / RTI > In other words, in the case of CC and MLO, the position of the breast tissue before pressing is the same but the position of the breast tissue after pressing is different.

As described above, the image synthesizing unit 204 can reconstruct the CC image from the MLO image, the MLO image from the CC image, and the like based on the deformation model of each position indicating the geometric positional relationship that varies after compression for each position.

For example, when an X-ray passing through a breast pressed in an inner and outer direction is received from the X-ray imaging apparatus 210, the image generating unit 202 generates an MLO image based on the X-ray, To generate an MLO deformation model. Then, the image synthesizer 204 can determine any one of the plurality of MLO deformation models stored in the storage unit (not shown) to match with the generated MLO deformation model. Here, the image combining unit 204 may determine a CC deformation model that matches the determined MLO deformation model.

Here, a plurality of MLO deformation models and CC deformation models are matched to each other according to the breast type classified according to whether the breast is dense or not, fat constituting the breast tissue, the proportion of water, race, Not shown).

Then, the image synthesizing unit 204 affine transforms the determined MLO deformation model and the CC deformation model, and geometrically matches the geometric positions of the respective breast tissues included in the MLO deformation model with the CC geometry Can be determined in the formation model.

For example, the geometric location of the CC breast tissue 314 that matches the geometry of the compressed MLO breast tissue 305 can be determined. The image combining unit 204 may map the image information corresponding to the geometric position of the MLO breast tissue 305 to the geometric position of the CC breast tissue 314. [ In the same manner, the image synthesizing unit 204 can reconstruct the CC image from the MLO image by mapping the image information to the geometric positions of all the tissues constituting the breast.

At this time, in the case of the affine transformation, since the line is also a line after the transformation, the affine transformation of the projection can be a projection of another position. Accordingly, the image synthesizer 204 can synthesize a synthetic mammo image of position 2 from the image of position 1 photographed by tomosynthesis using only a projective transform.

204 Also, the image combining unit 204 may reconstruct the image of the position 1 photographed by the tomosynthesis into the image of the synthetic tomo position 2 based on the 3D conversion. In other words, the image combining unit 204 may reconstruct the composite tomography image of another position.

204

4 is a flowchart illustrating an image reconstruction method according to an embodiment of the present invention.

In FIG. 4, the image reconstruction method can be performed by the image reconstruction apparatus of FIG.

In step 401, the image reconstruction apparatus 200 can generate the X-ray image of the position 1 based on the X-ray passing through the subject in the state of being pressed in accordance with the position 1. [

For example, the image reconstruction apparatus 200 can generate an MLO image by receiving X-rays that have passed through the breast while the breast is being pressed in the inner and outer direction from the X-ray imaging apparatus 210. Then, the image reconstruction apparatus 200 can estimate the attenuation coefficient in the three-dimensional space from the X-ray photographic image at position 1.

In step 402, the image reconstruction apparatus 200 can generate a deformation model of position 1 based on the X-rays passing through the breast in a state in which the breast is pressed in the inner and outer oblique directions. Here, the deformation model of position 1 can indicate the geometric position of the breast tissue as the breast is pressed under position 1.

In step 403, the image reconstruction apparatus 200 may determine a deformation model of the position 2, which is previously stored, by matching the deformation model of the position 1 from the storage unit (not shown). The image reconstruction apparatus 200 can determine a geometric position matching the geometric position of each tissue included in the deformation model of the position 1 based on the Affine Transform from the deformation model of the position 2.

In operation 404, the image reconstruction apparatus 200 maps the image information corresponding to the geometrical position of each tissue included in the deformation model of the position 1 to the geometric position of each tissue included in the deformation model of the matching position 2 , It is possible to synthesize the X-ray image of the position 2 from the estimated attenuation coefficient.

As described above, the image reconstruction apparatus 200 reconstructs the image assuming that the breast is pressed under the position 2, which is the other position, based on the image photographed in the state in which the breast is pressed under the position 1, It can reduce the pain caused by multiple pressures, discomfort, and pressure.

The contents omitted in FIG. 4 can be referred to FIG. 1 to FIG.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (16)

An apparatus for reconstructing an image from an image of an object to be examined using X-rays,
An image generating unit for generating an X-ray image of a position 1 based on an X-ray passing through an object under pressure which is pressed according to position 1;
A damping coefficient estimating unit for estimating a damping coefficient in a three-dimensional space from the photographed images of the position 1; And
An image for synthesizing an X-ray image of a position 2 from the attenuation coefficient based on a deformation model corresponding to the position 1 and a deformation model corresponding to a position 2 in which the subject is pressed in a posture different from the position 1 Synthesizing unit
And an image reconstruction unit for reconstructing the image. The method according to claim 1,
Wherein the image synthesizer comprises:
And the X-ray image of the position 2 is synthesized based on the attenuation coefficient in a state in which the subject is pressed in accordance with the position 1. The method according to claim 1,
In the X-ray image of the position 1,
(MLO) image and a vertical direction photographing (CC) image,
In the X-ray image of the position 2,
Wherein the image is one of the remaining images excluding the X-ray image of the position 1 among the inner and outer oblique direction photographing (MLO) image and the vertical direction photographing (CC) image. The method according to claim 1,
In the deformation model corresponding to the position 1,
And a geometric position corresponding to each of the pressed tissues constituting the subject when the subject is squeezed in the inward and outward directions. The method according to claim 1,
Wherein the image synthesizer comprises:
A geometric position matching the geometric position of each tissue included in the deformation model corresponding to the position 1 is determined from the deformation model corresponding to the position 2 based on an affine transformation, And the X-ray image of the position 2 is synthesized by mapping the image information corresponding to the position to the matched geometric position. The method according to claim 1,
The image generation unit may include:
Wherein the sharpness of the X-ray image of the position 1 is adjusted by adjusting a projection dose of at least one of the X-ray images taken at the position 1. The method according to claim 1,
Wherein the image synthesizer comprises:
A geometric position matching with a geometrical position of each tissue included in the deformation model corresponding to the position 1 based on the anatomical information estimated from the attenuation coefficient at each point in the three-dimensional space is referred to as a deformation And the X-ray image of the position 2 is synthesized by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position. 1. An image reconstruction method performed by an apparatus for reconstructing an image from an image of an object to be examined using X-rays,
Generating an X-ray image of a position 1 based on an X-ray having passed through a subject under a pressure in accordance with the position 1;
Estimating a damping coefficient in a three-dimensional space from the photographed images of the position 1; And
Synthesizing an X-ray image of position 2 from the attenuation coefficient based on a deformation model corresponding to the position 1 and a deformation model corresponding to a position 2 in which the subject is pressed in a posture different from the position 1
And reconstructing the reconstructed image. 9. The method of claim 8,
The step of synthesizing the X-ray image of the position 2 comprises:
Wherein the X-ray photographed image of the position 2 is synthesized based on the attenuation coefficient in a state where the subject is pressed in accordance with the position 1. 9. The method of claim 8,
In the X-ray image of the position 1,
(MLO) image and a vertical direction photographing (CC) image,
In the X-ray image of the position 2,
Wherein the image is one of the remaining images except for the X-ray image of the position 1 among the inner and outer oblique direction photographing (MLO) image and the vertical direction photographing (CC) image. 9. The method of claim 8,
In the deformation model corresponding to the position 1,
And a geometric position corresponding to each of the pressed tissues constituting the subject when the subject is squeezed in the inward and outward directions. 9. The method of claim 8,
The step of synthesizing the X-ray image of the position 2 comprises:
Determining from the deformation model corresponding to the position 2 a geometric position matching with a geometrical position of each tissue included in the deformation model corresponding to the position 1 based on an affine transformation; And
Synthesizing the X-ray image of the position 2 by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position
And reconstructing the reconstructed image. 9. The method of claim 8,
The step of generating the X-ray image of the position 1 comprises:
Wherein the sharpness of the X-ray image of the position 1 is adjusted by adjusting a projection dose of at least one of the X-ray images taken at the position 1. 9. The method of claim 8,
The step of synthesizing the X-ray image of the position 2 comprises:
A geometric position matching with a geometrical position of each tissue included in the deformation model corresponding to the position 1 based on the anatomical information estimated from the attenuation coefficient at each point in the three-dimensional space is referred to as a deformation Determining from the model; And
Synthesizing the X-ray image of the position 2 by mapping the image information corresponding to the geometrical position of each tissue to the matched geometric position
And reconstructing the reconstructed image. 9. The method of claim 8,
In the X-ray image of the position 1,
Tomosynthesis images taken by internal and external oblique (MLO)
The X-ray image of the position 2 is.
Wherein the synthetic mammography image is a synthetic mammo image obtained by synthesizing the tomosynthesis image. A computer-readable recording medium on which a program for executing the method of any one of claims 8 to 15 is recorded.

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