RU2655091C2 - Tomography apparatus and method for reconstructing tomography image thereof - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: group of inventions relates to medical equipment, namely to tomographic visualization system means. Tomography apparatus contains one or more processors that receive partial images of an object, which are used to obtain the first information indicating the amount of movement of the object, and include a first image obtained at a first time by using data obtained in a first angular section with an angle less than 180° and in which the first time is included, and a second image obtained at a second time by using data obtained in a second angular section opposite the first corner section with an angle less than 180° and in which the second time is included, the second angular cross section does not overlap the first angular cross-section. Also, first information indicating a movement amount of the object is obtained by using the first image and the second image, reconstruct the target image of the object at the target time, which is one of the time points between the first time and the second time and which is included in an angular section different from the first and second angular cross-sections, based on the first information. Method of reconstructing the tomographic image is performed by means of a tomography apparatus.

EFFECT: use of a group of inventions makes it possible to reduce the blurriness of the image caused by motion artifacts.

15 cl, 34 dwg

Description

FIELD OF THE INVENTION

One or more embodiments of the present invention relate to a tomographic apparatus and method for reconstructing its tomographic image.

BACKGROUND OF THE INVENTION

Medical imaging devices are used to obtain images of the internal structure of the object. Medical imaging devices, which are non-invasive testing devices, capture the image and provide the processed image to the user, including processed structural parts, internal tissues and the flow of fluids in the human body. A user who, for example, is a doctor, can diagnose a patient’s health and illness by using a medical image provided by a medical image processing apparatus.

A tomographic apparatus is a typical apparatus among apparatuses for capturing an image of an object by projecting x-ray radiation onto a patient. As used herein, a tomographic apparatus includes a computed tomography (CT) apparatus.

From medical imaging apparatuses, a tomographic apparatus can provide an image of a cross-section of an object that clearly shows the internal structure, such as organs, such as the kidneys, lungs, etc., of an object, without overlapping between them, in contrast to a conventional X-ray unit. Accordingly, the tomographic apparatus is widely used for the accurate diagnosis of diseases. In the description below, a medical image obtained with a tomographic apparatus is called a tomographic image.

In order to obtain a tomographic image, a tomographic scan of an object using a tomographic apparatus is performed, as a result of which initial data are obtained. The tomographic image is reconstructed using the obtained source data. The source data may be projection data obtained by projecting x-rays in the direction of the object, or a synogram, which is a group of fragments of projection data.

For example, to obtain a tomographic image, an image reconstruction operation is performed using a synogram obtained by tomographic scanning. The tomographic reconstruction operation is described in detail below with respect to FIG. 1A and 1B.

FIG. 1A and 1B are representations for describing a tomographic imaging and reconstruction operation.

In detail, FIG. 1A is a diagram for describing a tomographic imaging operation of a tomographic apparatus that performs a tomographic scan while rotating around an object 25 and obtains corresponding source data. FIG. 1B is a synogram obtained by tomographic scanning and reconstructed tomographic image.

The tomographic apparatus generates and projects x-ray radiation in the direction of the object 25, and the x-ray radiation passing through the object 25 is detected by an x-ray detector (not shown). The x-ray detector generates input data corresponding to the detected x-ray.

In detail, refer to FIG. 1A; the x-ray generator 20, which is part of the tomographic apparatus, projects the x-ray radiation in the direction of the object 25. During the tomographic scanning performed by the tomographic apparatus, the x-ray generator 20 rotates around the object 25 and receives many fragments of the first, second, and third source data 30, 31 , and 32 according to the angle of rotation. In detail, the x-ray generator 20 obtains the first, second, and third source data 30, 31, and 32 by detecting an x-ray beam applied to the object 25 at positions P1, P2, and P3, respectively. The source data may be projection data.

To generate one tomographic image of the cross section, the x-ray generator 20 performs tomographic scanning during rotation of at least 180 ° (degrees).

Turning to FIG. 1B; as described in FIG. 1A, a synogram 40 can be obtained by combining the first, second, and third projection data 30, 31, and 32, which are obtained by moving the x-ray generator 20 in a predetermined angle range. The synogram 40 is obtained by tomographic scanning performed during rotation of the x-ray generator 20 for one cycle. A synogram 40 corresponding to one cyclic rotation can be used to generate one tomographic image of the cross section. One cyclic rotation can be approximately more than half a revolution or one revolution in accordance with the technical requirements of the tomography system.

The tomographic image 50 is reconstructed by performing a rear projection with filtering on the synogram 40.

Typically, an X-ray generator 20 requires approximately 0.2 seconds to rotate half a revolution.

When an object that is the target of a tomographic scan moves, the movement of the object occurs during one cycle. Due to the movement of the object, motion artifacts may occur during the reconstruction of the tomographic image.

FIG. 2 is a view for describing motion artifacts existing in the reconstructed tomographic image 200. FIG. 2 illustrates a tomographic image obtained by a complete reconstruction method in which the image is reconstructed using input data obtained by rotating 360 degrees or more around the object 210.

Turning to FIG. 2; when motion artifacts are present on the reconstructed tomographic image 200, the farthest (from the center) edge 220 of object 210 is unclear due to motion artifacts. In addition, the inner edge 230 of the reconstructed tomographic image 200 is fuzzy due to the movement of the object 210.

Motion artifacts in the tomographic image degrade the quality of the tomographic image and, therefore, when a user, such as a doctor, reads the tomographic image and diagnoses the disease, the user cannot accurately read the tomographic image and diagnose the disease.

Thus, when a tomographic scan is performed on a moving object, it is important to reconstruct a tomographic image in which blurred images caused by motion artifacts are reduced.

DISCLOSURE

TECHNICAL PROBLEM

Motion artifacts on the tomographic image degrade the quality of the tomographic image and, therefore, when a user, such as a doctor, reads a tomographic image and diagnoses a disease, the user cannot accurately read the tomographic image and diagnose the disease.

TECHNICAL SOLUTION

As described above, when a tomographic scan is performed on a moving object, it is important to reconstruct a tomographic image in which blurred images caused by motion artifacts are reduced.

USEFUL EFFECTS

One or more embodiments of the present invention may provide an image with reduced motion artifacts.

DESCRIPTION OF DRAWINGS

These and / or other aspects will become apparent and will be easier to understand from the following description of embodiments, considered in conjunction with the accompanying drawings, in which:

FIG. 1A and 1B are views for describing tomographic imaging and reconstruction operations;

FIG. 2 is a view for describing motion artifacts existing in a reconstructed tomographic image;

FIG. 3 is a schematic representation of a tomography system;

FIG. 4 is a block diagram illustrating the structure of a tomography system according to one embodiment of the present invention;

FIG. 5 is a block diagram illustrating a structure of a communicator;

FIG. 6 is a block diagram illustrating a tomographic apparatus according to one embodiment of the present invention;

FIG. 7 is a block diagram illustrating a tomographic apparatus according to another embodiment of the present invention;

FIG. 8A and 8B are representations for describing a reconstruction of a tomographic image according to a half reconstruction method;

FIG. 9A and 9B are views for describing a scanning mode for tomographic scanning;

FIG. 10A and 10B are representations for describing the shape of an X-ray beam projected in the direction of an object;

FIG. 11 is a view for describing the operation of a tomographic apparatus according to one embodiment of the present invention;

FIG. 12 is a view for describing the operation of a tomographic apparatus according to one embodiment of the present invention;

FIG. 13A, 13B, and 13C are representations for describing the movement of an object;

FIG. 14 is a view for describing the movement of an object;

FIG. 15 is a view for describing a reconstruction operation of a target image;

FIG. 16A and 16B are views for describing setting a target time;

FIG. 17 is a view for describing setting a target time;

FIG. 18A and 18B are views for describing a reconstruction of a target image indicating an object that is not moving;

FIG. 18C and 18D are representations for describing motion artifacts that may be generated during reconstruction of a target image indicating an object that is moving;

FIG. 18E is a view for describing an object represented in a 3D tomographic image;

FIG. 19A and 19B are representations for describing a measurement of a magnitude of an object’s movement;

FIG. 20A and 20B are views for describing a reconstruction operation of a target image;

FIG. 20C is a reconstructed target image;

FIG. 21A and 21B are views for describing a reconstruction operation of a target image;

FIG. 21C is a reconstructed target image;

FIG. 22A and 22B are views for describing a warping operation used to reconstruct a target image;

FIG. 23A and 23B are views for describing a warping operation used to reconstruct a target image;

FIG. 24A and 24B are views for describing a reconstruction operation of a target image;

FIG. 25A and 25B are views for describing reconstructed target images;

FIG. 26 is a view for describing a measurement of the magnitude of an object's movement

FIG. 27 is a view for describing motion artifacts existing in a reconstructed tomographic image;

FIG. 28 is a view for describing motion artifacts existing in a reconstructed tomographic image;

FIG. 29A and 29B illustrate user interface screens shown on a tomography apparatus according to embodiments of the present invention;

FIG. 30 is a view illustrating a user interface screen shown on a tomography apparatus according to one embodiment of the present invention;

FIG. 31A and 31B are views illustrating a user interface screen shown on a tomography apparatus according to one embodiment of the present invention;

FIG. 32 is a flowchart for explaining a tomographic image reconstruction method according to one embodiment of the present invention; and

FIG. 33 is a flowchart for explaining a tomographic image reconstruction method according to another embodiment of the present invention.

FIG. 34A is a reconstructed target image generated by a conventional CT system.

FIG. 34B is a reconstructed target image obtained by a tomographic apparatus according to exemplary embodiments of the present invention.

THE BEST WAY

This application claims the priority of provisional patent application US No. 61/942731, filed February 21, 2014, Korean patent application No. 10-2014-0093405, filed July 23, 2014 to the Korean Intellectual Property Rights Protection Service, and Korean patent application No. 10-2014-0115697, filed September 1, 2014, in the Korean service for the protection of intellectual property rights, the disclosures of which are incorporated herein in their entirety by reference.

One or more embodiments of the present invention include a tomographic apparatus that can reduce the occurrence of motion artifacts in a reconstructed tomographic image, and a method for reconstructing its tomographic image.

One or more embodiments of the present invention include a tomographic apparatus that can reduce a dose of radiation affecting a human body, and can reconstruct a tomographic image in which the occurrence of motion artifacts is reduced, and a method for reconstructing its tomographic image.

Additional aspects will be formulated in part in the description below and, in part, will be apparent from the description or may be learned by practice of the presented embodiments.

According to one or more embodiments of the present invention, the tomographic apparatus includes: a data receiver receiving a first image and a second image, which are partial images, by using data obtained in a first angular section corresponding to the first time and a second angular section corresponding to the second time and opposite the first angular section, by performing a tomographic scan of the object that is moving, and obtaining the first a formation indicating the magnitude of the movement of the object using the first image and the second image; and an image reconstructor reconstructing the target image indicating the object at the target time based on the first information.

Each of the first angular section and the second angular section may be less than 180 °.

The first information can be obtained by comparing only the first image and the second image.

The object depicted in the first image and the object depicted in the second image may differ from each other in at least one of size, position and shape.

On the target image, the degree of motion correction (MC) of the object indicated on the target image can be changed in accordance with the target time.

In the target image, the correction of the movement of the object, when the target time can correspond to the average angle between the first angular section and the second angular section, can be improved in comparison with the correction of the movement of the object when the target time does not correspond to the average angle.

The first information may indicate the amount of movement of the surface forming the object.

The first information may indicate the amount of motion of the surface forming the object corresponding to the time points, as information corresponding to the field of the motion vector between the first and second image.

The motion vector field can be measured by non-rigid registration.

In the first information, the value of the time point and the value of the magnitude of the motion of the surface, indicated as the field of the motion vector, can have a linear relationship.

The data recipient can obtain the first image and the second image using the source data obtained by performing tomographic scanning in the angular section of one cycle, which is less than one revolution, and the first angular section and the second angular section can be, respectively, the initial section and the final section of the angular sections in one cycle.

An image reconstructor can reconstruct a target image by using a plurality of projection data fragments corresponding to a plurality of projections, which are the source data obtained by performing a tomographic scan during rotation of less than one revolution.

The first information may contain information about the surface movements of the object in all directions, while the object is displayed on the first image and the second image.

The image reconstructor can estimate the magnitude of the movement of the object at the target time based on the first information and reconstructs the target image based on the estimated magnitude of the movement.

An image reconstructor may reconstruct a target image by deforming a plurality of partial images representing parts of an object based on the first information.

The image reconstructor may deform the image grid in order to image the object based on the first information, and reconstructs the target image by using the deformed image grid.

During the reverse projection process, the image reconstructor can reconstruct the target image by deforming the pixel corresponding to the data obtained by CT scanning based on the first information.

The image reconstructor can reconstruct the target image by deforming the center of the voxel indicating the object based on the first information and performing back projection on the position of the deformed voxel.

The tomography apparatus may also include displaying a user interface receiving information indicating a relationship between time and the amount of movement of an object indicated in the first information through a user interface screen for setting the first information, wherein the data recipient receives first information based on information indicating the relationship .

The data receiver can perform a tomographic scan in an angular section having an angle of 180 + an additional angle in a half reconstruction method using a rearranged parallel beam.

The data receiver can obtain projection data corresponding to an angular section having an angle of 180 + an additional angle, and the additional angle can be from about 30 to 70 °.

The tomography apparatus may also include a display device displaying a user interface screen that includes a menu for setting a target time.

The tomography apparatus may also include a display device that displays a screen that contains at least one of the first information, a user interface screen for setting the first information, the target time, and the target image.

The data recipient can divide the projection data obtained by performing tomographic scanning while rotating around an object into a plurality of paired projection sectors, obtain a plurality of pairs of partial images including a first image and a second image in each of the plurality of paired projection sectors, and obtain the first information by using said plurality of pairs of partial images corresponding to said plurality of paired projection sectors.

The tomographic apparatus may further comprise: a display device displaying a medical image; and a user interface for setting the study area of the medical image, wherein the data recipient retrieves at least one surface included in the study area, sets at least one of the first angular section, the second angular section, the initial position of the angular section in one cycle, the final position angular section in one cycle and the target time based on the direction of the extracted surface, receives the first image and the second image in the first angular section and second m angular section respectively corresponding to the installation, and receives the first information indicating the size of the object by using the first image and the second image.

The data receiver can set at least one of the first angular section, the second angular section, the first time, the second time, the initial position of the angular section in one cycle, the final position of the angular section in one cycle and the target time, taking into account the direction in which the object is moving.

The object may be at least one of a heart, abdominal cavity, uterus, brain, chest, and liver.

The object may be a heart expressed by surface, and the heart may include at least one of tissues having different brightness values in a predetermined area.

The data receiver may perform a tomographic scan according to at least one of the axial scanning method and the screw scanning method.

The data recipient may receive additional information, which is information about the movement generated in at least one of the object or area outside the object during the tomographic scan, and may receive first information indicating the magnitude of the movement of the object based on the first image, second image and more information.

The data recipient may receive a plurality of pairs of partial images, including a first image and a second image that depict the same part of an object, by applying a screw scanning method, and may obtain first information by using said plurality of pairs of partial images.

According to one or more embodiments of the present invention, the tomographic apparatus comprises: a data receiver receiving a first image indicating a first image indicating a surface of a part of an object and a second image indicating a surface of a part of an object, which are partial images corresponding to a first time and a second time, by performing tomographic scanning of an object that is moving and receiving first information indicating the movement of the object through using the first image and the second image; and an image reconstructor reconstructing the target image by using the first information.

The first image and the second image may be partial images reconstructed using data obtained in the first angular section and the second angular section having values less than 180 degrees.

The first information can be obtained by comparing only the first image and the second image.

The object depicted in the first image and the object depicted in the second image may differ from each other in at least one of size, position and shape.

The first information may be information indicating the amount of motion of the surface forming the object corresponding to a point in time in the form of information corresponding to the field of the motion vector between the first image and the second image.

The data receiver can perform tomographic scanning in an angular section in one cycle, which is less than one revolution, and the first time can correspond to the initial cross section of the angular section in one cycle, and the second time corresponds to the final cross section of the angular section in one cycle.

An image reconstructor may reconstruct a target image indicating an object at a target time between a first time and a second time based on the first information.

On the target image, the degree of motion correction of the object included in the target image may vary according to the target time.

In the target image, the correction of the movement of the object in the case where the target time can correspond to the average angle between the first angular section and the second angular section can be improved in comparison with the correction of the movement of the object in the case when the target time does not correspond to the average angle.

An image reconstructor can reconstruct a target image by using a plurality of projection data fragments corresponding to a plurality of projections, which are the source data obtained by performing a tomographic scan during rotation of less than one revolution.

The first information may be information indicating the magnitude of the movement of the surface of the object during the period between the first time and the second time.

According to one or more embodiments of the present invention, a tomographic image reconstruction method includes: obtaining a first image and a second image, which are partial images, using data obtained in a first angular section corresponding to a first time and a second angular section corresponding to a second time and opposite the first angular section, by performing a tomographic scan on an object that is moving; obtaining first information indicating the amount of movement of the object at a time by using the first image and the second image; and reconstructing the target image indicating the object at the target time based on the first information.

Each of the first angular section and the second angular section may be less than 180 °.

Obtaining the first information may include obtaining the first information by comparing only the first image and the second image.

The object depicted in the first image and the object depicted in the second image may differ from each other in at least one of size, position and shape.

On the target image, the degree of correction of the movement of the object indicated on the target image may vary according to the target time.

In the target image, the correction of the movement of the object, when the target time can correspond to the average angle between the first angular section and the second angular section, can be improved in comparison with the correction of the movement of the object when the target time does not correspond to the average angle.

The first information may indicate the amount of movement of the surface forming the object.

The first information may indicate the magnitude of the motion of the surface forming the object corresponding to the time instant in the form of information corresponding to the field of the motion vector between the first and second image.

The motion vector field can be measured by applying flexible registration.

In the first information, the value of the time point and the value of the magnitude of the surface motion indicated in the form of the field of the motion vector can have a linear relationship.

Obtaining a first image and a second image may include obtaining a first image and a second image by using the source data obtained by performing tomographic scanning in an angular section in one cycle that is less than one revolution, and the first angular section and the second angular section can be initial section and the final section of the angular section in one cycle, respectively.

Reconstruction of the target image may include reconstruction of the target image by using a plurality of projection data fragments corresponding to the plurality of projections, which are the source data obtained by performing a tomographic scan during rotation of less than one revolution.

The first information may include information about the movement of the surface of the object in all directions, while the object is displayed on the first image and the second image.

The reconstruction of the target image may include an estimate of the magnitude of the movement of the object at the target time based on the first information and reconstruction of the target image based on the estimated magnitude of the movement.

Reconstruction of the target image may include reconstruction of the target image by deforming a plurality of partial images indicating portions of an object based on the first information.

Reconstruction of the target image may include: deformation of the center of the voxel indicating the object based on the first information; and reconstructing the target image by performing back projection with respect to the position of the deformed voxel.

The method may also include receiving information indicating the relationship between the time and the amount of movement of the object indicated in the first information through the user interface screen to set the first information, and upon receipt of the first information, the first information is obtained based on information indicating such a dependence.

The acquisition of the first image and the second image may include performing a tomographic scan in an angular section having an angle of 180 + an additional angle in the half reconstruction method using a rearranged parallel beam.

The method may further include obtaining projection data corresponding to an angle of 180 + an additional angle, wherein the additional angle has a value of from about 30 to 70 °.

The method may further include displaying a user interface screen, which may include a menu for setting a target time.

The method may further include displaying a screen, which may comprise at least one of the first information, a user interface screen for setting the first information, the target time, and the target image.

Obtaining a first image and a second image may include: dividing the projection data obtained by performing tomographic scanning while rotating around an object into a plurality of paired projection sectors; and obtaining a plurality of pairs of partial images including a first image and a second image in each of said plurality of paired projection sectors, and obtaining the first information may include obtaining first information by using said plurality of pairs of partial images corresponding to said plurality of projection sectors.

The method may also include: displaying a medical image; and setting the study area of the medical image, wherein obtaining the first image and the second image may include extracting at least one surface included in the study area, setting at least one of the first angular section, the second angular section, the position of the beginning of the angular section beyond one cycle, the position of the end of the angular section in one cycle and the target time based on the direction of the extracted surface, obtaining the first image and the second image in the first corner tion section, and a second angular section, respectively, according to the setting, and obtaining a first information indicating the size of the object by using the first image and the second image.

The method may also include setting at least one of the first angular section, the second angular section, the first time, the second time, the position of the beginning of the angular section in one cycle, the position of the end of the angular section in one cycle and the target time, taking into account the direction in which moving object.

The object may be at least one of a heart, abdominal cavity, uterus, brain, chest, and liver.

The object may be a heart expressed by surface, and the heart may include at least one of tissues having different brightness values in a predetermined region.

The method may further include performing a tomographic scan according to at least one of the axial scanning method and the screw scanning method.

The method may further include obtaining additional information, which is information about the movement generated in at least one of the object or outside the object during tomographic scanning, while obtaining the first information may include obtaining first information indicating the amount of movement of the object based on the first image, the second image, and additional information.

Obtaining a first image and a second image may include acquiring a plurality of pairs of partial images including a first image and a second image that depict the same part of an object by applying a screw scanning method, and obtaining the first information may include obtaining a first information by using said plurality of pairs of partial images.

According to one or more embodiments of the present invention, a tomographic image reconstruction method includes: acquiring a first image and a second image that indicate the same parts of an object forming surface and are partial images corresponding to a first time and a second time by performing a tomographic image scanning an object that is moving; obtaining first information indicating the movement of the object by using the first image and the second image; and reconstructing the target image by using the first information.

The first image and the second image may be partial images reconstructed using data obtained in the first angular section and the second angular section, which are less than 180 °.

Upon receipt of the first information, the first information can be obtained by comparing only the first image and the second image.

The object depicted in the first image and the object depicted in the second image may differ from each other in at least one of a size, position and shape.

The first information may be information indicating the amount of motion of the surface forming the object corresponding to a point in time in the form of information corresponding to the field of the motion vector between the first image and the second image.

Obtaining a first image and a second image may include performing a tomographic scan in an angular section in one cycle that is less than one revolution, and the first time may correspond to the initial cross section of the angular section in one cycle, and the second time may correspond to the final cross section of the angular section in one cycle.

Reconstructing the target image may include reconstructing the target image indicating the object at the target time between the first time and the second time, based on the first information.

On the target image, the degree of motion correction of the object included in the target image may vary according to the target time.

In the target image, the correction of the movement of the object in the case when the target time corresponds to the average angle between the first angular section and the second angular section can be improved in comparison with the correction of the movement of the object in the case when the target time does not correspond to the average angle.

Reconstruction of the target image may include reconstruction of the target image by using a plurality of projection data fragments corresponding to the plurality of projections, which are the source data obtained by performing a tomographic scan during rotation of less than one revolution.

The first information may be information indicating the magnitude of the movement of the surface of the object during the period between the first time and the second time.

According to one or more embodiments of the present invention, the tomographic apparatus comprises: a data receiver receiving a first partial image and a second partial image, which are partial images, using data obtained in each of the initial angular section and the final angular section opposite the first angular section , by performing a tomographic scan of an object that is moving, and obtaining first information indicating the dependence of dy time and the magnitude of the object surface corresponding to the motion vector field between the first partial image and the second partial image; and an image reconstructor reconstructing the target image indicating the object at the target time based on the first information.

According to one or more embodiments of the present invention, the tomographic apparatus comprises: a data receiver receiving a first image and a second image, which are partial images corresponding to the first time and the second time and indicating the same parts of the surfaces forming the object by performing tomographic scanning an object that is moving, and obtaining first information indicating the movement of the object by using the first of images and the second image; and an image reconstructor reconstructing the target image indicating the object at the target time by deforming at least one of the source data necessary for the half reconstruction and the image obtained by performing filtered back projection on the source data based on the first information.

According to one or more embodiments of the present invention, the tomographic apparatus comprises: a data receiver receiving a first image and a second image, which are partial images, using data obtained in a first angular section corresponding to a first moment in time and a second angular section corresponding to a second time and opposite the first angular section, by performing a tomographic scan of the object and obtaining the first information indicating value of the object by using the first image and the second image; and an image reconstructor reconstructing the target image indicating the object at the target time based on the first information.

According to one or more embodiments of the present invention, the medical imaging apparatus comprises: a data receiver receiving a first image and a second image, which are partial images, using data obtained in a first angular section corresponding to a first moment in time and a second angular section corresponding to a second time and opposite the first angular section, by performing a tomographic scan of the object that is moving, and obtaining howling information indicating the size of the object by using the first image and the second image; and an image reconstructor reconstructing the target image indicating the object at the target time based on the first information.

OPTION FOR THE INVENTION.

The advantages and features of one or more embodiments of the present invention and methods for their implementation can be better understood using the following detailed description of embodiments and the accompanying drawings. In this regard, the present embodiments may take various forms and should not be construed as limited by the descriptions set forth in this disclosure. On the contrary, these embodiments are presented in such a way that this disclosure is complete and complete and fully conveys the concept of the present embodiments to a person skilled in the art, and the present invention will be defined only by the appended claims. Similar numerals refer to like elements throughout the description of the invention.

Further, in the present disclosure, the terms used in the description of the invention will be briefly defined, and embodiments will now be described in detail.

All terms, including descriptive or technical terms, used in this disclosure should be construed as having meanings that are obvious to a person skilled in the art. However, the terms may have different meanings in accordance with the intentions of a person skilled in the art, case studies or when new technologies arise. In addition, some conditions may be arbitrarily selected by the applicant, in which case the meaning of the selected terms will be described in detail in the detailed description of the invention. Thus, the terms used in this disclosure should be defined based on the meaning of the terms, taking into account the description throughout the specification.

When the part "includes" or "contains" an element, if there is no specific description of the opposite, the part may also include other elements, not excluding other elements. In addition, the term “block” in embodiments of the present invention means a software component or hardware component, such as a user programmable gate array (FPGA) or application specific integrated circuit (ASIC), and performs a specific function. However, the term “block” is not limited to software or hardware. A “block” may be formed in such a way that it is located in an address storage device, or may be formed in such a way as to operate with one or more processors. Thus, for example, the term “block” may refer to components such as software components, object-oriented software components, class components, and task components, and may include processes, functions, attributes, procedures, routines, program segments code, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays or variables. The function provided by components and “blocks” can be associated with fewer components and “blocks”, or can be divided into additional components and “blocks”.

Below will be discussed in detail embodiments, examples of which are illustrated in the accompanying drawings. In this regard, the existing options for implementation may take various forms and should not be construed as limited to the descriptions set forth in the present disclosure. In the description below, well-known functions or constructions are not described in detail since they would reduce the clarity of the embodiments due to unnecessary details.

As used in the present disclosure, the term “and / or” includes any possible combinations of one or more of the listed elements. Expressions such as “at least one of”, when preceded by a list of items, modify the entire list of items and do not change individual items in the list.

Throughout the specification, “image” can mean multidimensional data formed from discrete image elements, such as pixels in a two-dimensional (2D) image and voxels in a three-dimensional (3D) image. For example, the image may include a medical image of an object captured by a tomographic imaging apparatus.

Throughout the specification, a “tomographic image” may mean an image obtained by performing a tomographic scan of an object by using a tomographic imaging apparatus, that is, an image obtained by projecting a beam of light, such as x-rays, in the direction of the object and visualizing using projection data. Throughout the specification, a “tomographic image” may mean an image generated by synthesizing a plurality of X-ray images obtained by capturing an image of an object while rotating the tomographic imaging apparatus around at least one axis relative to the object.

Throughout the specification, examples of an “object” may include a human, animal, or part of a human or animal. For example, examples of an object may include at least one of organs, such as a liver, heart, uterus, brain, breast, abdominal cavity, etc., and blood vessels. In addition, the object may include a model. Model means a material having a volume that is very close in density and effective atomic number to the body, and may include a spherical model having a characteristic similar to a physical body.

Throughout the specification, a “user” may be, but is not limited to, a medical expert, including a doctor, a nurse, a medical laboratory technologist, an image medical expert, and a technical specialist repairing a medical device.

Since a tomographic system, such as a CT system, is able to provide an image of the cross-section of an object, the tomographic system can display the internal structure (for example, organs, such as the kidneys, lungs, etc.) of the object without overlapping between them, unlike the usual x-ray imaging apparatus.

In detail, a tomographic system may include all tomographic devices, such as a computed tomography (CT) apparatus, optical coherence tomography (OCT) or PET-CT system. In the description below, the CT system is illustrated as a tomographic system.

The tomographic system can receive a plurality of fragments of image data with a thickness of not more than 2 mm from a few tens to several hundred times per second, and then can process said plural fragments of image data so that the tomographic system can provide a relatively accurate cross-sectional image of the object. According to the prior art, only a horizontal image of the cross section of an object can be obtained, but this complexity has been overcome due to various image reconstruction methods. Examples of 3D image reconstruction methods are shown below:

Shadow Surface Display (SSD) is the initial 3D visualization method that displays only voxels that have predefined unit values on the Hounsfield scale (HU).

Maximum Intensity Projection (MIP) / Minimum Intensity Projection (MinIP) is a 3D visualization method that displays only voxels that have the highest or lowest HU of the voxels used to construct the image.

Volume visualization (VR) is a visualization method capable of adjusting the color and transparency of the voxels used to construct the image according to the research areas.

Virtual endoscopy is a method that allows for endoscopic observation using a 3D image reconstructed using the VR method or SSD method.

Multiplane reformatting (MPR) is a method used to reconstruct an image into another cross-sectional image. The user can reconstruct the image in each desired direction.

Editing is a method that includes editing adjacent voxels in order to allow the user to easily observe the study area when visualizing the volume.

Voxels of interest (VOIs) are a method that shows only the selected area when visualizing volumes.

The tomography system 100 according to one embodiment of the present invention will now be described with reference to FIG. 3. The tomography system 100 may include devices of various types.

FIG. 3 schematically illustrates a tomographic system 100. Referring to FIG. 3; the tomography system 100 may include a gantry 102, a table 105, an x-ray generator 106, and an x-ray detector 108.

The Gantry 102 may include an X-ray generator 106 and an X-ray detector 108.

Object 10 may be placed on table 105.

The table 105 may move in a predetermined direction, for example, at least one of the directions up, down, left and right during the tomographic imaging procedure. In addition, table 105 may tilt or rotate a predetermined amount in a predetermined direction.

Gantry 102 can also be tilted a predetermined amount in a predetermined direction.

FIG. 4 is a diagram illustrating the structure of a tomographic system 100 according to one embodiment of the present invention.

The tomography system 100 may include a gantry 102, a table 105, a control unit 118, a memory 124, an image processing unit 126, an input unit 128, a display device 130, and a communicator 132.

As described above, the object 10 can be placed on the table 105. In the present embodiment, the table 105 can move in a predetermined direction, for example, at least one of the directions up, down, right and left, and the block 118 can control the movement of the table 105 management.

The gantry 102 may include a pivoting frame 104, an x-ray generator 106, an x-ray detector 108, a rotation drive unit 110, a data acquisition system (DAS) 116 and a data transmission unit 120.

The gantry 102 may include a pivoting frame 104 having a loop shape configured to rotate about a predetermined axis of rotation RA. In addition, the swing frame 104 may be in the form of a disk.

The pivoting frame 104 may include an X-ray generator 106 and an X-ray detector 108 that are opposed to each other so as to have a predetermined scanning area (FOV). The pivoting frame 104 may also comprise a screening raster 114. A screening raster 114 may be placed between the x-ray generator 106 and the x-ray detector 108.

Although in FIG. 4, it is illustrated that the pivoting frame 104 includes one x-ray generator 106, and the pivoting frame 104 may include a plurality of x-ray generators. In addition, in the case where the pivoting frame 104 includes a plurality of X-ray generators, the pivoting frame 104 contains a plurality of X-ray detectors corresponding to the plurality of X-ray generators. In detail, one x-ray generator 106 is one x-ray source. For example, in the case where the pivoting frame 104 comprises two X-ray generators 106, it can be said that the pivoting frame 104 contains a dual source. In the description below, in the case where the pivot frame 104 includes one x-ray generator 106, this x-ray generator 106 contained in the pivot frame 104 is called a single source. In addition, in the case where the rotary frame 104 includes two x-ray generators (not shown), two x-ray generators included in the rotary frame 104 are called a dual source. Of the two x-ray generators forming a dual source, one x-ray generator is called the first source, and the other x-ray generator is called the second source. In addition, the tomographic system 100, in which the x-ray generator 106 is contained in the rotary frame 104, is called a single source tomographic apparatus, and when two x-ray generators are contained in the rotary frame 104, it may be called a dual-source tomography apparatus.

In a medical imaging system, x-rays reaching the detector (or photosensitive film) include not only the attenuated main radiation, which forms a useful image, but also scattered radiation, which degrades the image quality. In order to transmit most of the main radiation and attenuate the scattered radiation, a screen raster 114 can be placed between the patient and the detector (or photosensitive film).

For example, screening raster 114 may be formed from alternately stacked strips of lead foil and an intermediate material such as a solid polymer material, a solid polymer, or a fibrous composite. However, the formation of the screening raster 114 is not limited to this.

The pivoting frame 104 may receive a trigger signal from the rotation drive unit 110 and may rotate the x-ray generator 106 and the x-ray detector 108 at a predetermined rotation speed. The rotary frame 104 may receive a start signal and power from the rotation drive unit 110 while the rotary frame 104 is in contact with the rotation drive unit 110 through a slip ring (not shown). In addition, the pivoting frame 104 may receive a trigger signal and power from the rotation drive unit 110 via wireless communication.

The x-ray generator 106 can receive voltage and current from a power distribution unit (PDU) (not shown) through a slip ring (not shown) and a high voltage electric generator (not shown), and then can generate and project the x-rays. In the case where the high voltage electric generator applies a predetermined voltage (hereinafter referred to as the lamp voltage) to the X-ray generator 106, the X-ray generator 106 can generate X-rays having a plurality of energy spectra corresponding to the voltage of the lamp.

The x-rays generated by the x-ray generator 106 can be emitted in a predetermined form due to the collimator 112.

The x-ray detector 108 may be located opposite the x-ray generator 106. The x-ray detector 108 may include a plurality of x-ray detection devices. Each of the plurality of X-ray detection devices mentioned above may establish one channel, but one or more embodiments of the present invention are not limited thereto.

The x-ray detector 108 can detect x-ray radiation that is generated by the x-ray generator 106 and which is transmitted through the object 10, and can generate an electrical signal corresponding to the intensity of the detected x-ray radiation.

The X-ray detector 108 may include an indirect-type X-ray detector for detecting radiation after converting the radiation into light, and a direct-type X-ray detector for detecting radiation after directly converting the radiation to electric charges. An indirect type X-ray detector may use a scintillator. In addition, a direct type X-ray detector may use a photon counting sensor. DAS 116 may be coupled to an X-ray detector 108. The electrical signal generated by the X-ray detector 108 may be collected by the DAS 116 in a wired or wireless manner. In addition, the electrical signal generated by the X-ray detector 108 may be transmitted to an analog-to-digital converter (not shown) through an amplifier (not shown).

According to the slice thickness or the number of slices, only a part of the data collected by the X-ray detector 108 can be transmitted to the image processing unit 126 via the data transmission unit 120, or the image processing unit 126 can only select a part of the data.

A digital signal may be transmitted to image processing unit 126 through data transmission unit 120. The digital signal may be transmitted to the image processing unit 126 by a wired or wireless method.

The control unit 118 can control the operation of each of the modules in the tomographic system 100. For example, the control unit 118 can control the operation of a table 105, a rotation drive unit 110, a collimator 112, DAS 116, a memory 124, an image processing unit 126, an input unit 128, a display device 130, communicator 132, etc.

The image processing unit 126 may receive data, for example, clean data before processing, which were obtained from the DAS 116 through the data transmission unit 120, and may perform preprocessing.

Pre-processing may include a correction process for sensitivity irregularities between channels and a process for correcting signal loss due to a rapid decrease in signal strength or due to an X-ray absorbing material such as metal, etc.

The output from the image processing unit 126 may be called projection data or source data. Projection data may be stored in memory 124 along with visualization conditions, such as lamp voltage, visualization angle, etc., during data acquisition.

The projection data may be a group of data values corresponding to the intensity of the x-ray radiation passing through the object 10. For convenience of description, it is assumed that a group of a plurality of fragments of the projection data simultaneously obtained from all channels in the same visualization position is called a projection data set.

The memory 124 may include at least one data medium from a flash memory type data medium, a hard disk type data medium, a microcard type multimedia data medium, a card type memory such as an SD card, an XD memory, etc. ., random access memory (RAM), random access static memory (SRAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), programmable ROM (PROM), magnetic memory, magnetic disk and optical disk.

The image processing unit 126 may reconstruct the cross-sectional image with respect to the object 10 by using the obtained projection data set. The cross-sectional image may be a 3D image. In other words, the image processing unit 126 can reconstruct the 3D image of the object 10 by applying the method of reconstructing a cone-shaped beam, etc., based on the obtained projection data set.

The input unit 128 may receive external input in relation to the conditions of the x-ray tomographic imaging, image processing conditions, etc. For example, the conditions of x-ray tomographic imaging may include voltage on the lamps, setting the energy value for a plurality of x-ray beams, choosing a visualization protocol, choosing an image reconstruction method, setting a scanning area, number of slices, slicing thickness, setting parameters for subsequent image processing, etc. In addition, image processing conditions may include image resolution, setting an attenuation coefficient for an image, setting an image combining ratio, etc.

The input unit 128 may include a device for receiving a predetermined input from an external source. For example, input unit 128 may include a microphone, keyboard, mouse, joystick, touch keyboard, touch pen, voice recognition device, gesture recognition device, etc.

The display device 130 may display an x-ray image reconstructed by the image processing unit 126.

Exchanges of data, power, etc. between the above elements can be accomplished by using at least one of wired communication, wireless communication and optical communication.

Communicator 132 may communicate with an external device, external medical device, etc. through server 134, etc. Communication will now be described with respect to FIG. four.

FIG. 5 is a diagram illustrating a structure of a communicator 132.

The communicator 132 can be wired or wirelessly connected to the network 301, and therefore can communicate with a server 134, an external medical device 136, or an external portable device 138. The communicator 132 can communicate with a hospital server or other medical devices in the hospital connected through the system Image Archiving and Transfer (PACS).

In addition, the communicator 132 can exchange data with an external device, etc., according to the standard for digital imaging and exchange in medicine (DICOM).

The communicator 132 can transmit and receive data related to the diagnostics of the object 10 through the network 301. In addition, the communicator 132 can transmit and receive a medical image received from a medical device 136, such as a magnetic resonance imaging (MRI) device, an X-ray device, etc.

In addition, communicator 132 may receive a diagnostic history or medical treatment schedule for a patient from server 134 and may use a diagnostic history or medical treatment schedule in clinical diagnosis for a patient. In addition, the communicator 132 can exchange data not only with the server 134 or the medical device 136 in the hospital, but also with the portable device 138 of the user or patient.

In addition, the communicator 132 may transmit device error information, quality control status information, etc. to a system administrator or service manager through network 301, and may receive feedback corresponding to the information.

FIG. 6 is a block diagram illustrating a tomographic apparatus 600 according to one embodiment of the present invention.

Turning to FIG. 6; the tomography apparatus 600 according to the present embodiment includes a data receiver 610 and an image reconstructor 620.

The tomographic apparatus 600 may be included in the tomographic system 100, which is described with respect to FIG. 3 and 4. In addition, the tomographic apparatus 600 may be included in the medical apparatus 136 or portable device 138 and may function when connected to the tomographic system 100.

In detail, the tomographic apparatus 600 may be all medical imaging devices that reconstruct images by using data obtained by using a beam of light passing through an object. In other words, the tomographic apparatus 600 may be all medical imaging devices reconstructing images using projection data obtained by applying a beam of light passing through an object. In detail, the tomographic apparatus 600 may be a computed tomography (CT) apparatus, optical coherence tomography (OCT) or PET-CT system. Accordingly, the tomographic image obtained by the tomographic apparatus 600 according to the present embodiment may be a CT image, an OCT image, or a PET image. In the drawings, which are discussed in the description below, a CT image is illustrated as a tomographic image. In addition, the tomographic apparatus 500 may be an MRI apparatus.

Furthermore, in the case where the tomographic apparatus 600 is included in the tomographic system 100 described in relation to FIG. 1, a data receiver 610 and an image reconstructor 620, illustrated in FIG. 6 may be included in the image processing unit 126 of FIG. four.

The recipient 610 data receives the first information indicating the movement of the object, in accordance with the period of time, by performing a tomographic scan of the object 10. The object may be a predetermined body. In detail, examples of an object may include at least one of a heart, abdomen, uterus, brain, chest, and liver. For example, an object may be a heart, which is represented by its surface. The heart may contain at least one of tissues having different brightness values in a predetermined area.

In addition, the data receiver 610 can obtain the source data by performing a tomographic scan while rotating around the object in less than one revolution. The source data may be projection data obtained by projecting radiation, such as x-rays, in the direction of the object, or a synogram, which is a group of projection data. In addition, the source data may be an image generated by performing back projection with filtering on projection data or a synogram. In detail, when the x-ray generator 106 in a predetermined position projects the x-ray radiation in the direction of the object, the observation point or the direction in which the x-ray generator 106 is facing the object is called a projection. Projection data indicates the source data obtained in accordance with the projection, and a synogram indicates the source data obtained by sequentially indicating a plurality of fragments of the projection data.

In detail, when the X-ray generator 106 emits a conical beam as it rotates around an object that is moving, the data receiver 610 can obtain the source data corresponding to the conical beam, and can convert the obtained source data to the original data corresponding to the parallel beam by rearranging the received source data. The first information can be obtained by using the source data corresponding to the parallel beam. In this case, the conical beam is converted into a parallel beam, which is called rearrangement, and the first information can be obtained by using the source data corresponding to the parallel beam. Rearrangement of the conical beam is described below in detail with respect to FIG. 10.

In detail, the data receiver 610 obtains data in a first angular section corresponding to a first time and a second angular section corresponding to a second time and opposite the first angular section by performing a tomographic scan of an object that is moving and acquiring a first image and a second image using data obtained in each of the first and second angular sections.

The image reconstructor 620 reconstructs the target image representing the object at the target time based on the first information.

The first information indicates the amount of movement of the object according to the time interval. In detail, the first information may indicate the movement of the surface forming the object at some point in time. The first information is described in detail below with respect to FIG. 13.

In detail, the data receiver 610 obtains a first image by using the original data obtained during the first angular section corresponding to the first time, and a second image by using the original data obtained during the second angular section corresponding to the first time and related to the paired angle to the first angular section (i.e., the angle of the second angular section and the angle of the first angular section are paired angles). As used herein, the term “first angular cross-section” or “second angular cross-section” refers to a partial angular cross-section included in the angular cross-section in one cycle, which is less than one revolution by rotation. In detail, each of the first and second angular section may have a value less than 180. In addition, the first and second images are partial images. The data receiver 610 receives information indicative of the movement of the object by using the first and second images. In detail, the data receiver 610 receives first information indicating an amount of movement of an object during the period between the first time and the second time. The magnitude of the movement may be the difference in at least one of the shape, size and position between the predetermined object included in the first image and the predetermined object included in the second image generated due to the movement of the object.

The first information is described below in detail with respect to FIG. 12 and 13.

Image reconstructor 620 may reconstruct a target image indicating an object at a target time. The target time can be set directly by the image reconstructor 620 or based on a predetermined value entered by the user. In addition, the target time may be the time between the first and second time. The setting of the target time by the user is described in detail below with respect to FIG. thirty.

The detailed operation of the tomographic apparatus 600 is described in detail below with respect to FIG. 7-19.

FIG. 7 is a block diagram illustrating a tomographic apparatus 700 according to another embodiment of the present invention;

Since the data receiver 710 and image reconstructor 720 of FIG. 7 correspond identically to the data receiver 610 and the image reconstructor 620 of FIG. 6, their redundant descriptions are omitted.

Turning to FIG. 7; tomography apparatus 700 may include a data receiver 710 and an image reconstructor 720. In addition, the tomographic apparatus 700 may further include at least one of a “gantry” 730, a display device 740, a user interface 750, a memory 760, and a communicator 770. Since the “gantry” 730, a display device 740, a user interface 750, memory 760 and the communicator 770, which are included in the tomographic apparatus 700, respectively, have the same operations and structures as the “gantry” 102, the display device 130, the input unit 128, the memory 124, and the communicator 132 from the tomographic system 100 of FIG. 4, their redundant descriptions are omitted.

The data receiver 710 performs a tomographic scan of the object and obtains first information indicating the movement of the object according to the time interval.

In detail, a data receiver 710 performs a tomographic scan of an object and obtains a first image corresponding to a first time and a second image corresponding to a second time. The data receiver 710 receives first information indicating a relationship between the amount of movement of the object and time based on the amount of movement between the first image and the second image. The first image and the second image may be images reconstructed according to the partial angular reconstruction (PAR) method. In detail, since the first image and the second image are images reconstructed using only the initial data obtained in an angular section, the first image and the second image are not complete images showing the entire object, but incomplete images showing only part of the object. In addition, an incomplete image showing a part of an object, such as the first and second images, may be referred to as a “partial image” or “partial angular image”.

The first time corresponds to the time when the initial data for reconstruction of the first image is obtained, and the second time corresponds to the time when the initial data for reconstruction of the second image is obtained. For example, when the first image is reconstructed by using the source data that was obtained to reconstruct the first image during the time cycle from 0 to time “a”, the first time may be time “a / 2”, which corresponds to the middle of the time cycle from 0 to time "A". In addition, when the second image is reconstructed by using the source data that was obtained for reconstructing the second image during the time cycle from time “b” to time “c”, the second time can be time “(c + b) / 2”, which corresponds to the middle of the time cycle from time “b” to time “c”.

In addition, the first image indicates the object at the first time, and the second image indicates the object at the second time.

An image reconstructor 720 reconstructs a target image showing an object at a target time based on the first information. In detail, the image reconstructor 720 reconstructs the target image by correcting the movement of an object based on the first information. In detail, the image reconstructor 720 may reconstruct the target image by warping an image indicating an object, an image grid to display an object, or a voxel indicating an object.

The term “warping” means adjusting the object included in the image to fit the state of the expected object by changing the state of the object included in the image, such as expanding, compressing, moving and / or changing the shape. The image reconstruction operation of the image reconstructor 720 is described below in detail with respect to FIG. 13-31.

The gantry 730 may comprise the x-ray generator 106 of FIG. 4, the x-ray detector 108 of FIG. 4 and DAS 116 of FIG. 4. The Gantry 730 projects x-rays in the direction of the object, detects an x-ray beam transmitted through the object, and generates input data corresponding to the detected x-ray.

In detail, the x-ray generator 106 generates and projects x-rays in the direction of the object while rotating around the object. Then, the X-ray detector 108 detects an X-ray beam transmitted through the object. DAS 116 generates raw data corresponding to the detected x-ray beam.

In the description below, the reconstruction of one tomographic image of the cross section by using the source data obtained by rotating the x-ray generator 106 by half a revolution or more and less than one revolution is called the half reconstruction method, and the reconstruction of one tomographic image of the cross section by using the original the data obtained by rotating the x-ray generator 106 by one revolution is called the full Instructions. In addition, in the description below, the time, angle, or phase of rotation of the X-ray generator 106, which rotates to obtain the initial data needed to reconstruct a single tomographic image of the cross section, is called a “one cycle”. In addition, the term “angular section in one cycle” can mean the angular section during which the x-ray generator 106 rotates to obtain the initial data necessary for the reconstruction of one tomographic image of the cross section. In addition, the angular cross section for one cycle may indicate a section of projection data necessary for the reconstruction of a single tomographic image of the cross section. In this case, it can be called the angular section for one projection data cycle.

For example, one cycle in the half reconstruction method may be 180 degrees or more, and one cycle in the full reconstruction method may be 360 degrees. For example, the angular cross-section for one projection data cycle in the half reconstruction method that uses a rearranged parallel beam can make an angle of 180 + the angle of the fan beam by adding the angle of the fan beam to 180 degrees. For example, when the angle of the fan beam is about 60, the angular section for one projection data cycle in the half reconstruction method can be about 240 (180 + 60) degrees. In addition, the angular cross section for one cycle in the complete reconstruction method can be 420 (360 + 60) degrees by adding the angle of the fan beam to 360 °.

In detail, the first time and the second time may be times or angular positions included in one cycle. In addition, the first image and the second image can be images reconstructed, respectively, using the original data obtained in the first angular section and the second angular section, different from the first angular section, which are included in the angular section in one cycle.

The display device 740 displays a predetermined screen. In detail, the display device 740 may display a user interface screen necessary for performing a tomographic scan or reconstruction of a tomographic image. The user interface screen displayed on the display device 740 is described in detail below with respect to FIG. 29-31.

The user interface 750 generates and outputs user interface data and receives input of a predetermined command or data from the user through the user interface screen. In addition, the output of the user interface screen from the user interface 750 is output to the display device 740. Then, the display device 740 can display the user interface screen. A user may recognize predetermined information or enter a predetermined command or data through a user interface screen displayed on the display device 740.

For example, user interface 750 may include an input device, such as a mouse, keyboard, or hardware buttons for entering predetermined data. For example, a user may enter a predetermined command or data by manipulating at least one of a mouse, keyboard, or other input devices included in user interface 750.

In addition, the user interface 750 may be configured as a touch keyboard. In detail, the user interface 750 may include a touch keyboard (not shown) that connects to a display panel (not shown) included in the display device 740, and may display a user interface screen on the display panel. Then, when a predetermined command is entered through the user interface screen, the touch keyboard recognizes the input and can recognize the input of the predetermined command by the user.

In detail, when the user interface 750 is configured as a touch keyboard, when the user touches a predetermined location on the user interface screen, the user interface 750 recognizes the touch location and can transmit information about the touch location to the image reconstructor 720. Then, the image reconstructor 720 may recognize a request or user command corresponding to the menu shown in the touch position, and may perform a tomographic image reconstruction operation according to the recognized request or command.

A memory 760 may store data obtained according to tomographic scanning. In detail, at least one of the projection data that is the source data and the synogram can be stored in the memory 760. In addition, various pieces of data or programs necessary for reconstructing the tomographic image may be stored in the memory 760, and the resulting reconstructed tomographic image may be stored. In addition, various pieces of data necessary to obtain the first information and the obtained first information may be stored in the memory 760.

In addition, the memory 760 may include at least one data medium from a flash memory type data medium, a hard disk type data medium, a microcard type multimedia data medium, a card type memory such as an SD card, an XD memory, and etc., random access memory (RAM), random access static memory (SRAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), programmable ROM (PROM), magnetic memory, magnetic disk and optical disk .

Communicator 770 can communicate with an external device or external medical device. For example, the communicator 770 is connected to an external tomographic system or tomographic apparatus, and can receive a first image and a second image. Also, the communicator 770 may receive initial data for reconstructing the first image and the second image. In this case, the data recipient 710 may receive the first image and the second image or source data for reconstructing the first image and the second image, through the communicator 770, and may receive the first information based on the received data.

The tomographic apparatuses 600 and 700 according to embodiments of the present invention can be applied to all methods of the PAR method, the complete reconstruction method, and the half reconstruction method. In addition, in tomographic apparatuses 600 and 700 according to embodiments of the present invention, a plurality of scanning modes are used to obtain a first image and a second image. In addition, in the tomographic apparatuses 600 and 700 according to the present embodiments, tomography can be applied according to both methods from the axial scanning method and the screw scanning method. In addition, in the tomographic apparatuses 600 and 700 according to embodiments of the present invention, an X-ray generator 106 may be used that generates X-rays having a plurality of shapes, such as a cone shape or a parallel shape.

In the case where the object is an object that moves, such as a heart, motion artifacts existing on the reconstructed tomographic image can be reduced by obtaining the initial data while reducing the time or angle corresponding to one cycle. Accordingly, the half reconstruction method can reduce artifacts of movement better than the full reconstruction method. Accordingly, in the description below, a case is described in which the half reconstruction method is used to reconstruct the target image.

An image reconstruction method, a scanning mode, and a form of X-ray radiation projected onto an object that are applicable to tomographic devices 600 and 700 according to one embodiment of the present invention are described below with respect to FIG. 8-10.

FIG. 8A and 8B are representations for describing the reconstruction of a tomographic image according to the half reconstruction method. In detail, FIG. 8A illustrates the rotation of an x-ray generator 106. FIG. 8B is a tomographic image reconstructed by the half reconstruction method.

In the case where the x-ray generator 106 projects a conical beam shaped like a fan in a predetermined position, the x-ray generator 106 performs a tomographic scan when rotated at an angle equivalent to 180+ angle (2 fan beam angle) in the half reconstruction method, and can reconstruct tomographic image through the use of source data obtained at an angle of 180+ (angle 2 of the fan beam). In addition, in the case when the reconstruction operation is performed by converting the fan beam into a parallel beam, or when the x-ray generator 106 projects a parallel beam, the tomographic image can be reconstructed using the initial data corresponding to the angular section having an angle of 180 + the angle of the fan beam in half reconstruction method. In other words, when a conical beam is used, the amount of input data increases with an increase in the angle of the fan beam compared to the case of reconstructing a tomographic image using input data obtained by using a parallel beam.

In detail, when the beam is not a conical beam, but a parallel beam, as described in FIG. 10B, the angle for additional rotation decreases to a value smaller than the angle of the fan beam “a” for the case of a conical beam, and the x-ray generator 106 rotates through an angle of 180 + a in one cycle. For example, when the angle of the fan beam is 60, the initial data obtained in the angular section 300 (180 + 2a) are necessary for the case of using a conical beam, and the initial data obtained in the angular section 240 (180 + a) are necessary for the case using a parallel beam. Accordingly, when a parallel beam is used, the half reconstruction method can be performed at an angle of 240 (180 + a) in one cycle.

FIG. 8A illustrates the use of a parallel beam in which the half reconstruction method is performed by using input data obtained in an angular cross section of, for example, 180 + the angle of the fan beam.

Turning to FIG. 8A; in the case where the x-ray generator 106 at the beam position 810 projects x-rays in the direction of the object 805, the x-ray detector 106 detects x-rays in the detection plane 820. The beam position 810 rotates around the object 805 as a center at an angle of 180 + a, which is one cycle. In addition, the detection plane 820 rotates in accordance with the beam position 810. In detail, the beam position 810 is shifted 180 from the + Y axis to the Y axis, and is further shifted by the angle of the fan beam equivalent to “a” to position 833.

In the half reconstruction method, one cross-section tomographic image is reconstructed using fragments of projection data obtained in the first “a” corner section 835, the intermediate corner section 837, and the last “a” corner section 836.

Turning to FIG. 8B; illustrated tomographic image 870, which is reconstructed using the original data obtained by the method of half reconstruction.

Since the x-ray radiation is projected in the direction of the object in the opposite direction in the first "a" corner section 835 and the last "a" corner section 836, the first "a" corner section 835 and the last "a" corner section 836 have the same projection. Accordingly, a part of the object reconstructed using the projection data obtained in the first “a” corner section 835 and a part of the object reconstructed using the projection data obtained in the last “a” corner section 836 are identical to each other.

For a moving object in the case when the data is received at different times, even if the data is obtained for the same part of the object, different pieces of data are obtained due to the movement of the object. The state of the object in the first "a" corner section 835 and the state of the object in the last "a" corner section 836 are different from each other. Accordingly, motion artifacts can be generated most strongly in the part of the object that is displayed using the projection data obtained in the first “a” corner section 835 and the projection data obtained in the last “a” corner section 836 in which the part of the object is displayed. which coincides with the part of the object in the first "a" corner section 835.

Turning to FIG. 8B; it can be seen that motion artifacts are generated in parts 882 and 883 of the surface indicating the object in the tomographic image 870 reconstructed in the half reconstruction method.

However, compared with the full reconstruction method, the half reconstruction method has a small angular section to obtain projection data. Accordingly, in the tomographic image 870 reconstructed by the half reconstruction method, motion artifacts can be reduced in comparison with the tomographic image obtained by the full reconstruction method. For example, compared with the farthest (from the center) surface 230 of the object 210, which is located on the tomographic image 200 illustrated in FIG. 2 and is fuzzy, the farthest (from the center) surface 881 of the object 880 in the tomographic image, 870 of FIG. 8B is less fuzzy.

In addition, it can be noted that the fuzziness is reduced on the inner surfaces 882 and 883 in comparison with the tomographic image 200 of FIG. 2, and thus motion artifacts are usually reduced in the reconstructed tomographic image 870.

As described above, in the tomographic image 870 reconstructed in the half reconstruction method, motion artifacts can be reduced compared to the tomographic image reconstructed in the full reconstruction method. In other words, if the time is reduced to obtain the initial data necessary for reconstructing the tomographic image of the cross section, the image with reduced motion artifacts can be reconstructed. In other words, if the time to obtain the initial data necessary for reconstructing tomographic images of the cross section is reduced, then the time resolution can be increased, and the dose of radiation to which the patient is exposed can be reduced. The tomographic apparatus according to the present embodiment and the method for reconstructing its tomographic image may apply the above full reconstruction method or the half reconstruction method.

Accordingly, in order to increase the temporal resolution in the present embodiment, the first image corresponding to the first time and the second image corresponding to the second time are obtained by applying the PAR method in which the image is reconstructed by obtaining the original data at a partial angle. The first image and the second image are described below in detail with respect to FIG. eleven.

In addition, tomographic apparatuses 600 and 700 according to embodiments of the present invention can obtain a first image and a second image by performing tomographic scanning according to a variety of scanning modes. The scanning mode used for tomographic scanning may include a prospective mode and a retrospective mode, described in detail below with respect to FIG. 9A and 9B. In addition, tomographic apparatuses 600 and 700 according to the present embodiments may perform tomographic scanning according to a variety of scanning methods. Scanning methods used in tomography include an axial scanning method and a helical scanning method, described in detail with respect to FIG. 9.

FIG. 9A and 9B are representations for describing a scanning mode and a scanning method used in tomographic scanning. In detail, FIG. 9A is a view for describing a tomographic scan according to an axial scanning method. In addition, FIG. 9A is a view for describing a tomographic scan according to a prospective mode. FIG. 9B is a view for describing a tomographic scan according to a helical scanning method. In addition, FIG. 9B is a view for describing a tomographic scan according to a retrospective method. The viewing method can be determined according to whether the heart rate of the patient undergoing imaging is constant or not. In addition, electrocardiographic (ECG) synchronization can be used to obtain the source data, which are used to reconstruct the image. In FIG. 9A and 9B, during tomographic scanning, table 105 of FIG. 4 moves in the axial direction of the patient 905.

Turning to FIG. 9A; The axial scanning method is a tomography method in which x-ray radiation is projected for scanning while the table 105 of FIG. 4 stands, table 105 moves to a predetermined interval from 901 to 902, and x-ray radiation is projected for a predetermined section 922, resulting in the initial data. The tomographic apparatuses 600 and 700 according to the present embodiments perform tomographic scanning by applying the axial scanning method, and thus at least one of the first image, the second image and the target image can be obtained.

Turning to FIG. 9A; for a person with a constant heart rate, the ECG signal 910 is regularly synchronized by using the prospective mode. In prospective mode, a predetermined section 921 is automatically selected at time t3, which is separated from peak R 911 by a predetermined time. X-ray radiation is applied to the object during a synchronized predetermined section 921 to obtain the source data. A predetermined section 922 is automatically selected at time t4, which is separated from the peak R 912 by a predetermined time. X-ray radiation is projected to scan an object while table 105 of FIG. 4 worth. After the table 105 is moved to a predetermined interval from 901 to 902, x-ray radiation is projected for a predetermined section 922 to obtain initial data. For the half reconstruction method, a method for performing a tomographic scan by moving in the axial direction of an object, as illustrated in FIG. 9A is called the axial half reconstruction method. The tomographic apparatuses 600 and 700 according to the present embodiments may employ an axial scanning method.

The data receiver 710 reconstructs tomographic images 931 and 932 obtained in synchronized sections 921 and 922.

Turning to FIG. 9B; a helical scanning method is a tomography method in which x-rays are constantly projected for tomography while the table 105 of FIG. 4 moves at a predetermined time from t = 0 to t = end. In detail, a tomographic scan is performed by continuously projecting x-rays onto an object, while table 105 of FIG. 4, on which a patient 905 containing an object lies, moves for a predetermined time at a predetermined speed. Accordingly, the motion path 950 from the x-ray source may be in the form of a spiral.

Turning to FIG. 9B; when the patient’s heart rate is irregular, as in the case of a patient with arrhythmia, the regularity of the heart rate worsens and, therefore, it is not possible to uniformly detect the cycle, as in the prospective mode. In this case, the ECG signal 960 is irregularly synchronized in retrospective mode. In retrospective mode, x-ray radiation is projected onto the object in all cycles of ECG signals or in a predetermined consecutive range of ECG signals in order to obtain initial data, and then partial cycles are selected for reconstruction of the tomographic image. In other words, in retrospective mode, the partial cycles used by the user to reconstruct the image are individually set to detect partial cycles 961, 962, and 963, and then the original data obtained during the detected cycles is used to reconstruct the tomographic image.

In retrospective mode, x-rays are constantly projected from a specific time t = 0 to t = end, whereby a tomographic scan is performed. Furthermore, since table 105 of FIG. 4 is constantly moving at a predetermined speed for a predetermined time, the path 950 of an X-ray light source (not shown) has a spiral shape. Among the half reconstruction methods, a method for performing an X-ray scan by continuously projecting X-ray radiation while the table is moving, as illustrated in FIG. 9B is called a helical half reconstruction method. The tomographic apparatuses 600 and 700 according to the present embodiments may employ a helical half reconstruction method.

In a detailed example for a patient having an irregular heart rate, a tomographic scan can be performed by applying a retrospective mode in a screw scanning method. Also, for a patient having a regular heart rate, a tomographic scan can be performed by applying a prospective mode in an axial scanning method. However, the present invention is not limited thereto, and tomographic scanning can be performed by applying the prospective mode to the helical scanning method and the retrospective mode to the axial scanning method.

FIG. 10A and 10B are representations for describing the shape of an X-ray beam projected in the direction of an object. In detail, FIG. 10A illustrates an example in which an X-ray generator 106 projects conical-beam X-rays. FIG. 10B illustrates an example in which an x-ray generator 106 projects x-ray radiation in the form of a parallel beam.

Turning to FIG. 10A; when the x-ray generator 106 moves along the path 1010 and projects the x-rays at a predetermined position 1020, the x-rays are projected in the direction of the object in the form of a cone 1030, as illustrated in FIG. 10A.

Turning to FIG. 10B; when the x-ray generator 106 moves along the path 1050 and projects the x-rays at predetermined positions 1060, the x-rays are projected in the direction of the object in the form of a parallel plane 1070, as illustrated in FIG. 10B.

Turning to FIG. 10B; when the X-ray generator 106 projects conical-beam X-rays, the cone-shaped beams are tuned, and thus, the beams can be tuned in parallel on a plane 1080, which is formed by connecting the row of the X-ray detector 108 and the path 1060, in which is placed by the x-ray generator 106. In other words, a conical beam can be converted into a pseudo-parallel beam for use. In addition, when the conical beam is converted to a parallel beam for use, the initial data in the conical beam is obtained by additional rotation of the x-ray generator 106 by the angle of the fan beam “a” compared to the parallel beam. In detail, when the angle of the fan beam is “a,” the x-ray generator 106 that projects the conical beam uses the original data obtained in the angular section having an angle of 180 + 2a to obtain the initial data corresponding to the angular section having an angle of 180 + a corresponding to the rearranged parallel beam.

As described with respect to FIG. 10, tomographic apparatuses 600 and 700 according to the present embodiments can be applied to both a CT apparatus emitting a conical beam and a CT apparatus emitting a parallel beam.

In the description below, for convenience of explanation, in one-cycle angular cross section, which is the angular cross-section through which the X-ray generator 106 is rotated to obtain projection data necessary to obtain one tomographic image of the cross-section, an angular cross-section other than 180 may be referred to as an additional angle. In the example described above, in the case where a parallel beam obtained by rearrangement of a conical beam projected from the X-ray generator 106 is used, the additional angle may be “2a”. In the case where a parallel beam is used, the additional angle may be “a”. In the case where a rearranged parallel beam is used, the projection data corresponding to the angular section having an angle of 180 + a is obtained by using the initial data obtained by rotating the x-ray generator 106, which projects the x-ray radiation in the form of a conical beam onto an angular section having angle 180 + 2a.

Furthermore, assuming that the section of projection data obtained for reconstructing one tomographic image of the cross section is the angular section in one cycle, the additional angle may express the angular section obtained by subtracting 180 from the angular section in one cycle of the projection data. In the example described above, when the X-ray generator 106 rotates into an angular section having an angle of 180 + 2a, projecting a conical beam, and projection data corresponding to an angular section having an angle of 180 + a is obtained by using a rearranged parallel beam, the angular section in one the projection data cycle may be 180 + a, and the additional angle in the angular section for one projection data cycle may be “a”.

In the tomographic apparatus 700 according to the present embodiment, the method of reconstructing the image by using the original data obtained in a partial angular section is used to obtain a first image and a second image. In detail, the first image and the second image can be images reconstructed using the original data obtained in the first angular section and the second angular section, which are included in the angular section in one cycle and which are different from each other sections. The acquisition of a first image and a second image in accordance with a partial reconstruction is described in detail below with respect to FIG. 11 and 12.

Since the X-ray generator 106 rotates at a constant speed and performs a tomographic scan, the angular value is proportional to the time value. Accordingly, when the value of the predetermined angular section decreases, the time spent to obtain the initial data in the predetermined angular section decreases. Thus, in the PAR method, while reducing the angular section used to reconstruct the partial angular image, the time resolution can be increased. Thus, the first and second images, which are partial angular images, are images having a high temporal resolution in which motion artifacts hardly exist. The first and second images can accurately show part of the object in the absence of fuzziness.

FIG. 11 is a view for describing the operation of a tomographic apparatus 700 according to one embodiment of the present invention.

In the description below, the case of performing a tomographic scan while rotating the x-ray generator 106 through an angle of 180 + an additional angle as an angular section in one cycle by applying the half reconstruction method described in FIG. 8 is described as an example. As described above, in the half reconstruction method, the additional angle, which is an angular cross-section other than 180, can be changed in accordance with at least one of the beam shape, the specification of the tomography system and the technical characteristics of the x-ray generator 106.

In the description below, the case of using a rearranged parallel beam is described as an example. Accordingly, a case in which an X-ray generator 106 rotates at an angular section having an angle of 180 + 2a and projects a conical beam, the data receiver 710 obtains initial data, for example, projection data corresponding to an angular section having an angle of 180 + a, using The data obtained by rotating the x-ray generator 106 to an angular section having an angle of 180 + 2a is described as an example. In addition, in the drawings and in the detailed descriptions to be considered, a case in which the angular section in one cycle has an angle of 180 + the angle of the fan beam, i.e., 180 + a, and the additional angle is the angle of the fan beam, i.e. “A”, in accordance with the angular section of the projection data obtained by using the rearranged parallel beam, is described and illustrated by way of example.

Turning to FIG. eleven; the angular section 1120 in one cycle can have an angle of 180 + an additional angle, which is the sum of 180 1130, (a / 2) 1141 and (a / 2) 1145. In addition, the specific value of the angle of the fan beam “a” can be changed in accordance with tomography system or the technical characteristics of the x-ray generator 106, and may be, for example, approximately 50-60 °.

In detail, the first angular section 1142 and the second angular section 1146 are angular sections included in the angular section 1120 in one cycle, and can be paired angles that are opposite each other. The difference in angle between the first corner section 1142 and the second corner section 1146 with respect to the paired angle is 180.

In detail, as illustrated in FIG. 11, the first angular section 1142 may be the initial section of the angular section 1120 in one cycle, and the second angular section 1146 may be the final section of the angular section 1120 in one cycle.

In the case where the first angular section 1142 and the second angular section 1146 have a pair angle ratio, since the projections in accordance with the first angular section 1142 and the second angular section 1146 are identical to each other, the surface of the object 1110 detected when the image of the object 1110 is captured in the first angular section 1142, and the surface of the object 1110 detected when the image of the object 1110 is captured in the second angular section 1146 are identical to each other.

For example, “a” in FIG. 11 may be 60 (a = 60), and the initial data corresponding to the angular section 60 is obtained by rotating the x-ray generator 106. Accordingly, the first image and the second image are obtained by using the source data obtained in the first angular section 1142, which is the first section at 60, and the second angular section 1146, which is the last section at 60.

Since the X-ray generator 106 rotates at a constant speed and performs a tomographic scan, the angular value is proportional to the time value. Accordingly, when the value of the predetermined angular section decreases, the time taken to obtain the initial data in the predetermined angular section decreases.

As described above, in the tomographic apparatus 700, a PAR method is used in which the first image and the second image are obtained by using the initial data obtained in the first angular section 1142 and the second angular section 1146, which are partial sections included in the angular section in one cycle. In other words, since the tomographic apparatus 700 reconstructs the image by using a relatively small angular section as compared to the half reconstruction method or the full reconstruction method, the time resolution can be increased and the motion artifacts can be reduced. In addition, in the present embodiment, since the amount of movement of the object is measured by using the first image and the second image, which are partial angular images, the amount of movement of the object can be measured more accurately.

Since the image is generated by performing motion correction on the object at the target time by using the first information, which is the motion information containing the accurately measured amount of motion, the reconstructed target image can have high temporal resolution and reduced motion artifacts. A tomographic apparatus according to the present embodiment and a method for reconstructing its tomographic image, which can reduce motion artifacts and increase time resolution, are described in detail below with respect to FIG. 12-25.

FIG. 12 is a view for describing the operation of a tomographic apparatus 700 according to one embodiment of the present invention.

Turning to FIG. 12; the angle 180 + a is set as the angular section 1210 for one cycle, and the initial data necessary for the reconstruction of the first image and the second image are obtained in the first angular section 1211 and the second angular section 1212, which are included in the angular section 1210 in one cycle and have pair angle ratio. In detail, the first angular section 1211 may be the initial section of the angular section 1210 in one cycle, and the second angular section 1212 may be the final section of the angular section 1210 in one cycle.

In detail, the x-ray generator 106 performs tomographic scanning while rotating around the object 1201, whereby projection data, synograms, etc., which are the initial data corresponding to the first angular section 1211, are obtained. Accordingly, the tomographic image 1231 is reconstructed using the obtained original data.

The initial data obtained in the first angular section 1211 and the second angular section 1212 may be data obtained by detecting x-ray radiation projected in the direction of the object from a single source or a double source. For example, in the case where a tomographic scan is performed using a single source, a tomographic scan can be performed by moving a single source in the first angular section 1211 and the second angular section 1212.

In another example, when a tomographic scan is performed using a dual source, a tomographic scan can be performed by moving at least one of the first source and the second source included in the dual source in at least one of the first angular section 1211 and the second angular section 1212. In detail, the source data can be obtained by rotating the first source in the first angular section 1211, and the source data can be obtained by rotating the second source in the second angular section 1212. In addition, the initial data can be obtained by rotating the first source in the first angular section 1211 or the first angular section 2001 of FIG. 20A, and a second angular section 1212 or a second angular section 2005 of FIG. 10A. In addition, the source data can be obtained by rotating the second source in at least a partial angular section of the angular section 1120 in one cycle, with the exception of the first angular section 1211 and the second angular section 1212, for example, in at least one of the third angular section 2002 , the fourth angular section 2003 and the fifth angular section 2004, which are described below with respect to FIG. 20A.

Moreover, various reconstruction methods can be used to reconstruct a tomographic image. For example, as a method for reconstructing a tomographic image in tomographic apparatuses 600 and 700, a reverse projection filtering method, an iterative method, etc. can be used.

According to the reverse projection method, the image is reconstructed by reverse projecting the projection data obtained in the plurality of projections onto the pixel plane and summing the reverse projected data. In detail, a reverse projection method can obtain an image similar to a real image by using a plurality of pieces of projection data in a plurality of directions. In addition, filtering may be additionally performed to remove artifacts existing in the reconstructed image and improve image quality.

The back projection method with filtering is an improvement on the back projection method and removes the fuzziness or artifacts that may occur in the back projection method. According to the reverse projection method with filtering, the source data is filtered before reverse projection is performed, and the filtered source data is reverse projected, whereby the tomographic image is reconstructed.

A back-projection filtering method is usually widely used for reconstructing a tomographic image, is a method that can be easily implemented and is effective in terms of the amount of computation for reconstructing an image. A back-projection filtering method is a method that mathematically performs the inverse transform with respect to the Radon transform, which is the process of obtaining a synogram from a 2D image. According to the reverse projection method with filtering, it is relatively simple to expand the 2D image to a 3D image. In detail, in the reverse projection method with filtering, the image is reconstructed by performing reverse projection after filtering the projection data by applying a Shepp-Logan filter, which is a kind of high-pass filter. In the description below, a case of reconstructing a tomographic image by applying a reverse projection filtering method is described as an example.

Turning to FIG. 12; the data recipient 710 obtains a tomographic image 1231 by performing backward projection with filtering on the original data obtained in the first angular section 1211. In detail, each of the first and second angular section 1211 and 1212 has a value less than 180. In order to further clarify the cleaning of surfaces 1235 and 1236 in the tomographic image 1231, the tomographic image 1231 is filtered, whereby a first image 1232 resulting from the reconstruction can be obtained. In detail, the first image 1232 may be an incomplete image that is reconstructed by the PAR method.

In detail, when a regrouped parallel beam is used, and the angular section per projection data cycle is 180 + a, the additional angle “a” can be set as the angle of the fan beam. In detail, the first angular section 1211 and the second angular section 1212 having an additional angle “a” can be set to approximately 30-70 ° (degrees).

In detail, the first angular section 1211 and the second angular section 1212 can be set equal to the experimentally optimized value for obtaining the first and second images having a high temporal resolution, and can be set taking into account the temporal resolution of the first and second images, technical characteristics of the tomographic apparatus 700 and / or visualization medium. The angular values of the first angular section 1211 and the second angular section 1212 and the temporal resolutions of the first image 1232 and the second image 1242 may be in a compromise ratio. In detail, with decreasing angular values of the first angular section 1211 and the second angular section 1212, the temporal resolutions of the first image 1232 and the second image 1242 increase. However, when the angular values of the first angular section 1211 and the second angular section 1212 are reduced, the part of the surface of the object being visualized is reduced. Accordingly, with decreasing angular values of the first angular section 1211 and the second angular section 1212, part of the surface of the object to extract the magnitude of the movement of the object decreases and, thus, the information about the movement may become relatively inaccurate.

Accordingly, taking into account the time resolutions of the first image 1232 and the second image 1242 and the accuracy of the motion information obtained through the first image 1232 and the second image 1242, the angular values of the first angular section 1211 and the second angular section 1212 can be optimally set.

The data recipient 710 obtains a tomographic image 1241 by performing a reverse projection with filtering on the original data obtained in the second angular section 1212. In order to further clean the surface images 1245 and 1246 on the tomographic image 1241, the tomographic image 1241 is filtered, whereby it can be obtained the second image 1242, which is the result of reconstruction. In detail, the second image 1242 may be an incomplete image reconstructed by the PAR method.

In FIG. 12, the case of reconstructing a 2D tomographic image, for example, the first and second images 1232 and 1242, is illustrated by way of example. An object represented as a surface in a 3D tomographic image can be represented as a face, for example, faces 1235 and 1236, as in the first and second images 1232 and 1242, illustrated in a 2D tomographic image.

As illustrated in FIG. 12, when the first information is obtained by using only the first and second images 1241 and 1242, which are 2D tomographic images, the degree of movement of an object can be identified by comparing the differences on the edge. For example, surfaces 1235 and 1245 included respectively in the first and second images 1241 and 1242 and showing the same surface of an object are compared to obtain the first information.

In addition, the 3D tomographic image is reconstructed, and the first and second images, which are 3D tomographic images, can be used. In the case when the 3D tomographic image is reconstructed from the first and second images, the magnitude of the object's movement can be identified by comparing the differences on the face, as shown in each of the first and second images, and by showing the same surface.

The data receiver 710 can obtain a first image 1241 and a second image 1242 by using the original data obtained by applying tomography according to the axial scanning method or the screw scanning method described in FIG. 9A.

In addition, the first image 1241 and the second image 1242 may be called one pair of partial images.

The data receiver 710 may obtain a first image 1241 and a second image 1242 by applying the screw scanning method described in relation to FIG. 9B. In the case where a screw scanning method is applied, projection data from a plurality of projections that project the same part of an object is divided into paired projection sectors, and thus, a first image and a second image can be obtained.

In addition, when the first image 1241 and the second image 1242 are called one pair of partial images, the first information can be obtained by using a plurality of pairs of partial images.

In detail, since the projection data fragments corresponding to the full projection are obtained in the screw scanning method, the fragments of the projection projection data are divided into a plurality of paired projection sectors, and thus the first image and the second image can be obtained in each of the paired projection sectors. Accordingly, a plurality of pairs of partial images corresponding to paired projection sectors can be obtained. Accordingly, the recipient 710 data can receive the first information through the use of pairs of partial images. In this case, the movement of the object can be predicted more accurately for each of the pair of projection sectors included in the angular section for one cycle of the first information by using pairs of partial images.

In addition, the x-ray detector 108 of FIG. 4, containing a plurality of 2D detectors, at one time receives projection data corresponding to a plurality of rows, and a tomographic scan is performed using a screw scanning method, and a plurality of fragments of the original data can be obtained to obtain pairs of partial images in the same pair projection sector to visualize the same position or the same part of the object. For example, when a table moves in the Z-axis direction and a tomographic scan is performed in an axial section, pairs of partial images can be obtained at the same Z-axis position of the object.

In the next direction, the case in which the table moves in the Z-axis direction and the tomographic scan is performed in axial section, as illustrated in FIG. 9B is described as an example. In detail, when a tomographic scan is performed by means of a helical scanning method, a plurality of source data sets can be obtained with respect to the same axial position on the Z axis (hereinafter referred to as the same z-position) due to movement of the table. For example, the screw pitch value is set, which is the interval of movement of the table in the screw scanning method, and thus, the table moves to the interval k of detector rows. In this case, the projection data obtained in the i-th row of the detector during the first rotation can coincide with the projection data obtained in the (i + k) -th row of the detector during the second rotation after the table has moved one step of the screw. The second rotation may be a rotation following the first rotation. Accordingly, a pair of partial images can be obtained using projection data obtained in the i-th row during the first rotation, and at least one pair of partial images can be obtained using projection data obtained in the (i + k) -th row at second rotation after the first rotation.

Alternatively, in a screw scanning method, a pair of partial images can be obtained using projection data obtained in the i-th row, and at least one pair of partial images can be obtained by interpolating fragments of the projection data obtained in rows adjacent to the i-th nearby.

Accordingly, the data receiver 710 can obtain multiple pairs of partial images corresponding to the same z-position by performing tomographic scanning in a screw scanning method. Then, the first information can be obtained by using pairs of partial images. In detail, when the magnitude of an object’s motion is measured by using pairs of partial images, the magnitude of the motion of an object can be more accurately measured compared to the case of measuring the magnitude of the motion of an object by using one pair of partial images, and accordingly, the first information that is more accurate can be obtained. .

In the description below, a case is illustrated in which the first and second images 1232 and 1242 are 2D tomographic images, as illustrated in FIG. 12, and the surface of an object illustrated as a face shown in the first and second images is described as an example.

Turning to FIG. 12; the first image 1232 and the second image 1242 identically show a face included in a predetermined part of the object.

As described above, since the first angular section 1211 and the second angular section 1212 have a pair angle ratio, both the first image 1232 and the second image 1242 show the same face of the same part of the object. Accordingly, when the first image 1232 and the second image 1242 are compared with each other, a difference between the surfaces of the same parts of the object included in the first image 1232 and the second image 1242 can be noticed, and the degree of movement of the object can be determined. In the case when the moving object must undergo tomographic scanning, at least one of the size, position and shape of the object included in the first image 1232 differs from this parameter for the object included in the second image 1242 due to the movement of the object.

Also, in detail, the movement of an object in a direction, for example, in the direction of the X axis, perpendicular to a direction, for example, a direction 1215, in which X-ray radiation is projected in the direction of the object in the first angular section 1211 and the second angular section 1212, can be more accurately identified than in the other direction (projection).

In addition, when using initial data obtained in an angular section having a relatively small angle, for example, a = 60, in contrast to the half reconstruction method or the full reconstruction method, since information about the movement of the object is obtained by using the first image 1232 and the second image 1242 having a high temporal resolution and fewer motion artifacts, the magnitude of the object’s movement between the first time and the second time can be measured accurately.

The data receiver 710 obtains first information indicating the movement of the object according to the time interval based on the amount of movement between the first image 1232 and the second image 1242. The operation of obtaining the first information is described below in detail with respect to FIG. 13.

FIG. 13A, 13B, and 13C are representations for describing the movement of an object. In detail, FIG. 13A is a view for describing a comparison of motion between a first image and a second image. FIG. 13B is a view for describing a motion amount between a first image and a second image. FIG. 13C is a view for describing the first information.

Turning to FIG. 13A; the first image 1310 and the second image 1320 are partial images identical to the first image 1232 and the second image 1242 of FIG. 12. However, for convenience of explanation, a case in which the first image 1310 and the second image 1320 are complete images is described as an example.

The first image 1310 and the second image 1320 are tomographic images schematically illustrating a moving object by capturing its images. In addition, in FIG. 13A, at least one of the objects 1311 and 1312, or 1321 and 1322 included in one image is shown as a round object.

In detail, to compare the magnitudes of the movements of objects, objects 1311 and 1312 included in the first image 1310 are compared with objects 1321 and 1322 included in the second image 1320. In accordance with the comparison result, the magnitude of the movement of each of the objects can be obtained, as illustrated in comparative image 1330.

Turning to FIG. 13B; surfaces indicating the same parts of objects included in the first and second images, 1310 and 1320, are compared with each other, and in this way motion vectors indicating the values of position and direction differences between the compared surfaces can be obtained. The motion vector can be used as the magnitude of the movement of an object. The information, which includes the motion vectors and indicates the magnitude of the motion of a predetermined part of the object, may be a motion vector field (MVF). In other words, MVF indicates the amount of movement of the surface forming the object.

MVF is information obtained to extract the motion of an object, and the magnitude of the motion of the object can be measured by using flexible registration. In addition, the magnitude of the motion of an object can be measured by applying a number of motion measurement techniques, such as hard recording, optical flow technique, and performance comparison technique.

In the description below, the case of using flexible registration to obtain MVF is described as an example.

In detail, a plurality of control points, for example, control points 1351 and 1352, are set on the image grid of the first image 1310 or second image 1320, and an optimal motion vector, for example, a motion vector 1356 and / or 1358, is calculated at each control point. The motion vector is a vector that includes the direction and size of the motion. The motion vectors at the corresponding control points are interpolated to obtain an MVF indicating the motion vectors in all voxels. For example, the B-spline free-form strain method can be used as a method of interpolating motion vectors. In addition, the optimization technique can be used as a method of calculating the optimal motion vector at each control point. In detail, in accordance with the optimization technique, the MVF is updated by repeatedly updating the motion vector at the control points, the first image 1310 or the second image 1320 is deformed based on the updated MVF, and the deformed first image or second image is compared with the second image 1320 or the first image 1310 before deformation . When the degree of similarity between the image before deformation and the image after deformation is the highest, the repetition ends, and a motion vector is calculated. The degree of similarity can be indicated by using a negative value of the sum of the squares of the difference in brightness values of the two images that are compared.

In another method, motion vectors can be obtained by setting a plurality of control points on the surface of an object and comparing control points indicating the same positions in the objects in the first image 1310 and the second image 1320. In detail, the relative differences between the control points are obtained by comparing the control points object in the first image 1310 and control points of the object in the second image 1320. The value of the relative differences can be used as a motion vector in the current cont Aulnay point. MVF indicates the motion vectors in all voxels obtained by interpolating the motion vectors at the corresponding control points. As in the above example, the B-spline free-form strain method can be used as a method of interpolating motion vectors.

Turning to FIG. 13C; since the angular section 1360 per cycle, the first angular section 1361 and the second angular section 1362 are identical to the angular section 1210 per cycle, the first angular section 1211 and the second angular section 1212, which are described in FIG. 12, their detailed descriptions are omitted in the present disclosure.

In addition, in FIG. 13C, which is a graph showing first information 1380, the X axis denotes an angular section for one cycle or time corresponding to one cycle, while the Y axis denotes a weight value W corresponding to the amount of movement.

In detail, the first information may be information corresponding to the MVF between the first image 1310 and the second image 1320, that is, information indicating an amount of movement of an object corresponding to a point in time. In detail, the first information may be information indicating an amount of motion of an object surface corresponding to time. Each time can be a specific time included in the time period of one cycle, corresponding to the angular section for one cycle. Since the time of one cycle is the time taken by the x-ray generator 106 included in the gantry 730 to rotate for one cycle, the angle of rotation of the gantry 730 can be used instead of the time in the first information. In addition, the gantry 730 may include at least one x-ray generator 106, as described above. In detail, the gantry 730 may comprise a single source or a dual source.

In addition, when the amount of motion of the second image 1320 obtained in the second angular section 1362 is measured by using the first image 1310 obtained in the first angular section 1361, which is the initial section of the angular section 1360 in one cycle, as a reference image, the amount of motion the first image 1310 may be a 0% motion value, and the amount of motion of the second image 1320 may be a 100% motion value. In the description below, the value of the motion vector field, which is the magnitude of the motion between the first image 1310 and the second image 1320, is expressed by the weight value of W. In addition, the magnitude of the motion can be the sum of the absolute values of all the motion vectors in the motion vector field. In addition, the magnitude of the movement can be expressed by conversion using W.

Furthermore, when the relationship between time and a weight value indicating the amount of movement of an object is linear, as illustrated in FIG. 13C, the weight value W and time can be shown in the form of a graph 1370, illustrated in section 1390. In addition, the shape of the graph 1370 corresponding to the first information can be freely set by the user or set as optimized for the object. For example, when the object is a heart, graph 1370 may have a non-linear shape in accordance with the state of the heart at the point in time at which the image should be reconstructed.

In detail, when the magnitude of the object’s movement and time are linearly dependent, the data receiver 710 can respectively match a zero MVF and MVF indicating the magnitude of the movement between the first and second images 1310 and 1320 with the first weight value and the second weight value. In detail, a zero MVF may correspond to a starting point of the angular section in one cycle, and an MVF indicating the amount of motion between the first and second images 1310 and 1320 may correspond to an ending point of the angular section in one cycle. Turning to FIG. 13C; in a graph 1370 indicating the first information 1380, a weight value of 0 indicating zero MVF corresponds to a starting point 0 of the angular section for one cycle 1360 or time t = 0, and a weight value of 1 indicating MVF expressing the amount of movement between the first image 1310 and the second image 1320, corresponds to the corner point 180 + a, which is the end point of the angular section 1360 in one cycle, or time t = end. In addition, a case in which time and weight value are linearly related to each other is described as an example.

The first time t1 corresponds to the first image, and the second time t2 corresponds to the second image. For example, if the initial data for reconstruction of the first image was obtained in a section from 0 to 0.03 seconds from 0.2 seconds corresponding to an angular section of 1360 in one cycle, then the first time can be a moment of time of 0.015 seconds, which is the average time of a section from 0 to 0.03 seconds. In other words, when a predetermined image is reconstructed using source data obtained at a predetermined section time, a point in time corresponding to a predetermined image may be an average time point of a predetermined section time. In addition, the first image 1310 corresponding to the first time t1 may correspond to the projection when the x-ray generator 106 is facing the object while being in a position corresponding to the first time t1. In addition, the second image 1320 corresponding to the second time t2 may correspond to the projection when the x-ray generator 106 is facing the object while being in the position corresponding to the second time t2.

In addition, in the first information, when the weight value is between 0 and 1, the minimum weight value “0” may correspond to the amount of movement in position or at a time when the size of the object decreases most in the angular section 1360 per cycle, and the maximum weight a value of “1” can correspond to the amount of movement in position or at a time when the size of the object is the largest in the angular section 1360 in one cycle.

In addition, in the first information, the relationship between the amount of motion and time can be determined according to a relationship that is modeled by a quadratic equation, or a relationship that is modeled by statistical information.

For example, the motion structure of an object can be statistically modeled. In detail, when the object is a heart, the movement of the heart is statistically modeled, and the shape of the graph 1370 in section 1390 in the first information can be set to correspond to the simulated heart movement.

In addition, in the first information, the shape of the graph indicating the structure of the movement of the object can be changed in accordance with the object. For example, when the object is the whole heart, the shape of the graph in the first information may reflect the structure of movement of the whole heart. In addition, when the object is a coronary artery entering the heart, the shape of the graph of the first information may reflect the structure of movement of the coronary artery. In addition, even when the object is a coronary artery entering the heart, the pattern of movement can change in accordance with the position of the coronary artery in the heart, and thus, the shape of the graph of the first information can be set to change in accordance with the position of the coronary artery. In addition, when the object is a mitral valve (MV) that is part of the heart, the shape of the graph of the first information may reflect the structure of the MV movement.

In addition, the structure of motion can vary in accordance with the partial region of the object that will be subjected to tomographic scanning. In this case, the first information can be obtained for each partial region in order to reflect a different motion structure for each partial region. The target image indicating the entire object can be reconstructed by performing motion correction for each partial area by using the first information obtained and different for each partial area. For example, when the object is the heart, the pattern of movement can vary along the left ventricle, right ventricle, left atrium, and right atrium. In this case, the first information can be individually obtained in the left ventricle, right ventricle, left atrium and right atrium, and movement correction is performed on a partial image of the left ventricle, right ventricle, left atrium and right atrium, and the motion-corrected partial images are synthesized for reconstruction target image indicating a heart.

In addition, in the first information, the relationship between the amount of movement and time can be set by the user. For example, the user can set the shape of the graph 1370 in section 1390 through the user interface 750. Setting the first information through the user interface 750 is described in detail below with respect to FIG. 28.

Also, so that the first information 1380 more accurately reflects the change in movement between the first image 1310 and the second image 1320, upon receipt of the first information 1380, the change in the movement of an object in the angular section between the first angular section 1361 and the second angular section 1362 can be estimated by use of source data obtained in the entire angular section 1360 in one cycle.

For example, the data receiver 710 compares the estimated projection data obtained by directly projecting the target image reconstructed by using the first information 1380 at the target time with the measured projection data obtained by tomographic scanning at the target time. In order to reduce the discrepancy between the estimated projection data and the measured projection data, the data receiver 710 can correct the first information 1380. As described above, the data receiver 710 can repeatedly correct the first information 1380 so that the first information 1380 can accurately reflect the movement of the object.

The image reconstructor 720 reconstructs the target image corresponding to the target time based on the first information.

FIG. 14 is a view for describing the movement of an object. Although the X-ray generator 106 projects the conical beam X-ray radiation, as illustrated in FIG. 4 described above, an example in which a conical beam is rearranged to be converted into a parallel beam for later use is described in FIG. 14. Accordingly, the case in which the beam projected in the first angular section 1411 and the second angular section 1412 is illustrated as a parallel beam, and the angular section in one cycle, making an angle of 180 + a, is described as an example.

Turning to FIG. fourteen; when the x-ray generator 106 performs tomographic scanning while rotating around the object 1405, the x-ray generator 106 runs along a circular path 1041 and projects the x-ray radiation in the direction of the object 1405. In detail, the x-ray generator 106 performs tomographic scanning when rotated around the object 1405 according to the half reconstruction method . The first angular section 1411 and the second angular section 1412 of FIG. 14 identically correspond to the first angular section 1361 and the second angular section 1362 of FIG. 13, respectively. In addition, the object 1405 of FIG. 14 may identically correspond to an object, for example, objects 1311 and 1321 illustrated in FIG. 13A.

In the case where the object included in the first image obtained in the first angular section 1411 corresponding to the first time t11 and the object included in the second image obtained in the second angular section 1412 corresponding to the second time t15 are compared with each other, thereby receive the magnitude of the movement of the object and the first information, and a change in the size of the object in the angular section 1410 per cycle can be predicted by using the first information.

For example, an object 1405 at a first time t11 corresponding to a first angular section 1411 has a first size 1420. As a result of a gradual increase in the size of an object 1405 in accordance with a period of time, an object 1405 may have a second size 1430 at a second time t15 corresponding to a second angular section 1412 .

When the x-ray generator 106 projects x-rays in the direction of the object 1405 when rotated during the first angular section 1411, the x-radiation is projected in the direction of projection of the x-rays 1470 and thus the surface, for example, the surfaces 1451, 1452, 1453, and 1454 of the object 1405 existing in directions parallel to the direction of projection of x-ray radiation 1470 are clearly selected and displayed.

Accordingly, surfaces 1451 and 1452 of object 1405 having a first size 1420 are illustrated in a first image, and surfaces 1453 and 1454 of object 1405 having a second size 1430 are illustrated in a second image.

The data receiver 710 obtains the first information by comparing the first image and the second image. Turning to part 1490 of FIG. fourteen; first information indicating the movement of object 1405 can be obtained by comparing surfaces 1451 and 1452 of object 1405 having a first size 1420 and surfaces 1453 and 1454 of object 1405 having a second size.

In detail, the first information indicates the movement of the object in accordance with time and includes information indicating movements in all directions on the face or on the surface of the component parallel to the projection direction of the x-ray projected in the direction of the object 1405 in the first angular section 1411 or second angular section 1412 In detail, surfaces 1451, 1452, 1453 and 1454, which are clearly depicted in the first image and the second image, are surfaces located in directions parallel to the x-ray projection direction 1470 of the x-ray projected at the first time and the second time, or in the first angular section 1411 and the second angular section 1412. Accordingly, the first information may include information about movements in all directions of the surfaces 1451, 1452, 1453 and 1454, clearly depicted in the first and second images.

In addition, the first information may indicate the movement of the object 1405 in a first direction 1480 perpendicular to the X-ray projection directions 1470, so that the movement of the object 1405 could be more easily compared with the movement of the object 1405 in a direction other than the first direction 1480. In detail, surface 1453 on the second image is part of an object 1405 corresponding to a surface 1451 in the first image. You can notice that the surface 1451 moves to the first value 1481 in the first direction 1480 so as to have a position change similar to 1453. In addition, the surface 1454 in the second image is part of the object 1405 corresponding to the surface 1452 in the first image. You can notice that the surface 1452 moves to the second value 1482 in the first direction 1480, so as to have a change in position similar to the surface 1454.

Furthermore, although in FIG. 14, the X-ray projection direction 1470 in the first angular section 1411 and the second angular section 1412 is illustrated in one direction, since the X-ray generator 106 projects X-rays in the direction of the object 1405 in a plurality of positions when rotated in the first angular section 1411, the X-ray projection direction 1470 in the first section may be at least one of the directions 1470 of the projection of x-ray radiation from 0 to a. Accordingly, the first direction 1480 perpendicular to the X-ray projection direction 1470 in the first angular section 1411 and the second angular section 1412 may be in a predetermined range corresponding to the x-ray projection direction 1470 in the first angular section 1411 and the second angular section 1412.

In FIG. 14, the direction in which the x-ray radiation is projected towards the object 1405 when the x-ray generator 106 is located at the center of the first angular section 1411 or the second angular section 1412 is illustrated, by way of example, as the x-ray projection direction 1470 in the first angular section 1411 or second angular section 1412. The first direction 1480 is illustrated with an example in which the first direction 1480 is perpendicular to the direction 1470.

For example, when the weight value and time corresponding to the amount of movement of an object in the first information are linearly dependent, as illustrated in FIG. 13C, the size of the object 1405 may increase linearly.

Accordingly, as illustrated in FIG. 14, it can be expected that the size of the object 1405 in the third position t12 changes by the first change amount 1442, and becomes larger than the first size 1420. Accordingly, it can be expected that the size of the object 1405 in the third time t12 may have a third size 1421.

Furthermore, it can be expected that the size of the object 1405 at the fourth time t13 changes by a second change amount 1444, and becomes larger than the first size 1420. Accordingly, it can be expected that the size of the object 1405 at the fourth time t13 can have a size of the fourth size 1422. It can be expected that the size of the object 1405 at the fifth time t14 is changed by the third sum of the change 1446 to be larger than the first size 1420. Accordingly, it can be expected that the size of the object 1405 at the fifth time t14 can have the size of the fifth size 1423.

In addition, the size of the object 1405 at the third time t12, at the fourth time t13, and at the fifth time t14 can be estimated by compressing the object 1405 having the second size 1430 based on the first information.

In detail, the size, shape and / or position of the object 1405 at the target time can be estimated by using the first information. In the example of movement of an object illustrated in FIG. 14, the image reconstructor 720 can estimate the amount of change in the size of the object 1405 at the target time by using the first information, and can generate the target image by deforming the object 1405 based on the estimated size of the change. In detail, deformation of an object shows the correction of the movement of the object. That is, a state, for example, at least one of the size, shape and position of the object at the target time is estimated by using the first information and, thus, the target image is reconstructed by correcting the movement of the object in accordance with the intended state.

FIG. 15 is a view for describing a reconstruction operation of a target image.

When the first information is received, the image reconstructor 720 reconstructs the target image indicating the object at the target time based on the first information. In detail, the image reconstructor 720 can estimate the magnitude of the movement of the object at the target time based on the first information and can reconstruct the target image based on the estimated magnitude of the movement.

In detail, the image reconstructor 720 may reconstruct the target image by using the first information and at least one of the plurality of partial angular images including the first image and the second image.

In detail, the image reconstructor 720 may reconstruct the target image by deforming partial images indicating portions of an object based on the first information.

The partial angular image used to reconstruct the target image may be an image reconstructed by using fragments of projection data obtained in a partial angular section, such as the first and second images. In addition, the partial angular image may be an image generated by performing reverse projection with filtering on a plurality of projection data fragments corresponding to a plurality of consecutive adjacent projections, or an image generated by performing reverse projection with filtering on fragments of projection data corresponding to a single projection.

For example, the image reconstructor 720 may reconstruct the target image at the target time Ttarget by deforming the object 1505 based on the first information. In detail, since the size of the object 1505 at the target time Ttarget can be accurately estimated using the first information, the image reconstructor 720 deforms the reconstructed tomographic image to fit the estimated size of the object using the projection data obtained over the angular section 1510 in one cycle, whereby reconstructing target image.

In addition, the image reconstructor 720 can reconstruct the target image by deforming the first image obtained in the first angular section 1530, the second image obtained in the second angular section 1540, and at least one partial image according to the size of the object 1505 at the target time Ttarget (t = Ttarget). Surfaces of an object 1505 that are not shown in at least one of the first image and the second image can be obtained by deforming at least one of the partial angular images reconstructed in accordance with the fragments of the projection data obtained in at least one of the angular sections except for the first angular section 1530 and the second angular section 1540 of the angular section 1510 in one cycle.

In the following description of the reconstruction operation of the target image by using the first information 1380 described in FIG. 13C are described in detail.

In addition, in FIG. 15, the patient’s abdominal cavity is illustrated as an example as an object, and a case of reconstruction of a plurality of axial planes is illustrated.

In detail, the image reconstructor 720 can reconstruct the target image by using a plurality of projection data fragments corresponding to the plurality of projections, which are the source data obtained when the x-ray generator 106 performs tomographic scanning during rotation. In detail, the image reconstructor 720 may obtain a target image by performing motion correction based on the first image information obtained by performing back projection with filtering on the projection data corresponding to the projections.

In detail, to reconstruct the target image into the target time Ttarget corresponding to a predetermined corner point 1520 in the angular section 1510 per cycle, a weight value is used that corresponds to the target time Ttarget and is obtained from the first information 1380.

For example, refer to FIG. 13C; the target weight value W1 corresponding to the target time Ttarget is obtained from the first information. A lot of reverse projection filtered images obtained by performing reverse projection with filtering on each of the fragments of the projection data corresponding to each of the projections obtained in the angular section 1510 in one cycle has a magnitude of motion corresponding to the weight value in each projection (or observation point ) Accordingly, in order to ensure that each back-projected filtered image has a state of movement of the object at the target time, the amount of motion corresponding to the difference between the target weight value W1 and the weight value relative to the projection (or observation point) corresponding to each back-projected filtered image, applied to each back-projected, filtered image for deformation. The target image can be reconstructed using a plurality of deformed, back-projected, filtered images. In detail, in the process of performing reverse projection with filtering on the projection data obtained in the angular section 1510 in one cycle, the pixel filtered by the rear projection is deformed by using the first information, and thus, the target image is reconstructed.

Also, the image reconstructor 720 can obtain an image by performing reverse projection with filtering on fragments of the projection data obtained in the angular section 1510 in one cycle, and then deform the resulting image by using the first information, thus performing reconstruction of the target image.

In detail, the image reconstructor 720 reconstructs the initial image by performing back projection with filtering on a plurality of projection data fragments, which are the original data obtained by tomographic scanning with rotation of less than one revolution. The movement of the object 1505 at the target time Ttarget is estimated based on the first information and can deform the initial image based on the estimated movement, whereby the target image is reconstructed.

In addition, the image reconstructor 720 may deform the image grid formed of the plurality of pixels in order to visualize the object 1505 based on the first information, and may reconstruct the target image by using the deformed image grid. The image reconstructor 720 may perform reverse projection with filtering on the projection data obtained by tomographic scanning with rotation of less than one revolution by using a deformed image grid, and may reconstruct the target image. Reconstruction of the target image by deformation of the image grid is described below in detail with respect to FIG. 23A and 23B.

In addition, the image reconstructor 720 may deform the center of the voxel indicating the object 1505 based on the first information and may reconstruct the target image by using the deformed voxel. Reconstruction of the target image using voxel warping is described below in detail with respect to FIG. 24A and 24B.

In addition, the target time Ttarget can be set equal to the time between the first time t1 and the second time t2. In detail, the target time Ttarget can be set equal to the average time between the first time t1 and the second time t2, which is described in detail below with respect to FIG. 16-18.

In addition, reconstruction of the target image using warping is described below in detail with respect to FIG. 20-24.

FIG. 16A and 16B are views for describing setting a target time.

Turning to FIG. 16; in the PAR method, the clearly depicted portion of the reconstructed image appears to differ in accordance with the viewing angle at which the x-ray radiation is projected. In detail, with regard to the surface areas of the object depicted in the reconstructed image, there are surface areas selected relatively more frequently and surface areas selected relatively less frequently in accordance with the viewing angle.

In detail, refer to FIG. 16A; when the x-ray radiation is projected toward the object in an approximately 5-hour direction 1620, the reconstructed image 1610 is illustrated by using the raw data generated by the detected x-ray radiation. Surfaces 1631 and 1632 extending in a direction parallel to the 5-hour direction 1620, as illustrated in FIG. 16A are clearly visible in the reconstructed image 1610, while a surface extending in the perpendicular direction to the 5-hour direction 1620 is not clearly visible.

Turning to FIG. 16B; when the x-ray radiation is projected towards the object in an approximately 7-hour direction 1660, the reconstructed image 1650 is illustrated by using the raw data generated by the detected x-ray radiation. Surfaces 1671 and 1672, surfaces extending in a direction parallel to the 7-hour direction 1660, as illustrated in FIG. 16B are clearly visible in the reconstructed image 1650, while a surface extending in the perpendicular direction to the 7-hour direction 1660 is not clearly visible.

In other words, the portion of the surface that is shown clearly differs according to the direction of the x-ray beam. In detail, a portion of a surface extending in a direction similar to that of an X-ray beam can be clearly depicted, unlike a portion of the surface of another region.

Accordingly, as described above, when the target time Ttarget is set as the average time between the first time t1 and the second time t2, the target image corresponding to the target time, Ttarget, can be reconstructed more accurately. In detail, when the target time Ttarget is set as the average time between the first time t1 and the second time t2, a part of the surface of the object that is not shown clearly according to the projection data obtained at the target time Ttarget is shown by deforming a part of the surface of the image that is clearly shown according to the projection data obtained in at least one of the first time t1 and the second time t2, and thus, the object at the target time Ttarget can be displayed more clearly.

FIG. 17 is a view for describing setting a target time.

Turning to FIG. 17; generally FIG. 17 is identical to FIG. 14. In detail, the object 1705, the first angular section 1711 and the second angular section 1712 of FIG. 17 correspond identically to the object 1405, the first angular section 1411 and the second angular section 1412 of FIG. 14. The surfaces 1721 and 1722 of the object 1720 are clearly depicted in the first image obtained in the first angular section 1711, as illustrated in FIG. 17. In addition, the surfaces 1761 and 1762 of the object 1760 are clearly depicted in the second image obtained in the second angular section 1712, as illustrated in FIG. 17.

Compared to the above, the surfaces 1741 and 1742 of the object 1740 in the image obtained in the angular section corresponding to the target time Ttarget are clearly depicted, as illustrated in FIG. 17.

In other words, the surfaces 1741 and 1742 of the object 1740, which are clearly depicted and correspond to the target time Ttarget, and the surfaces 1721 and 1722 or 1761 and 1762 of the object 1740 or the object 1760, which are clearly shown and correspond to the first and second images, are parts that do not overlap together. Accordingly, the target time Ttarget is set as the average time between the first time t1 and the second time t2, and then the target image indicating the state of the object at the set target time can be reconstructed.

In detail, when rendering an object 1705, parts of the surface, for example, surfaces 1722 and 1721 or 1761 and 1762, extending in a direction similar to direction 1791, can be depicted by deforming at least one of the first and second images, and part of the surface, for example, the surface 1741 and 1742, extending in a direction parallel to the direction 1741, can be depicted by deforming the image obtained in an angular section corresponding to the target time Ttarget. Accordingly, even surfaces not clearly displayed at the target time Ttarget can be clearly displayed on the reconstructed target image.

Although in FIG. 17, the case of reconstructing the target image by deforming the back projection filtered with the partial angle image is described as an example, the image reconstructor 720 can reconstruct the target image by adjusting the projection data itself. In detail, each piece of projection data obtained in an angular section for one cycle can be adjusted in accordance with the state of the object at the target time Ttarget. In detail, fragments of projection data included in the angular section for one cycle depict various parts of the object according to the projection. Accordingly, the image reconstructor 720 can reconstruct the target image by evaluating the state of the object at the target time Ttarget by using the first information, adjusting each set of pieces of projection data corresponding to the set of projections according to the estimated state of the object, and performing reverse projection with filtering on the configured projection data.

FIG. 18A and 18B are views for describing reconstruction of a target image indicating an object that is not moving. In detail, FIG. 18A illustrates that an x-ray generator 106 performs tomographic scanning while rotating around an object 1801. In addition, FIG. 18B illustrates an operation of performing back projection on projection data obtained by filtering source data obtained through performing a tomographic scan.

In FIG. 18A, a case in which an X-ray generator 106 rotates around an object 1801 and performs a tomographic scan and a tomographic image is reconstructed by a back-projection filtering method is described as an example. In addition, a case in which the object 1801 comprises a circular target 1802, as illustrated in FIG. 18A is described as an example. Furthermore, as described in FIG. 13, the angular section 1360 per cycle is an angle of 180 + the angle of the fan beam, which is a section of projection data. In FIG. 18A, however, a case in which a tomographic scan is performed by rotation through 180 is described as an example for ease of explanation.

Turning to FIG. 18A; by passing the x-ray generator 106 along the original path 1810, which is circular, and projecting the x-ray radiation toward the object 1805 in each of a plurality of positions having a predetermined angular interval, projection data is obtained. Projection data is filtered, resulting in filtered projection data. In FIG. 18A, a plurality of points located on the original path 1810 indicate the positions at which the x-ray generator 106 is located and projects the x-ray radiation. For example, when moving at a predetermined interval, such as 0.5, 1, or 3, the x-ray generator 106 can project x-rays in the direction of the object 1805. The rotation starts at the first time T1 and stops at the second time T2. Accordingly, the first time T1 corresponds to a rotation angle of 0, and the second time T2 corresponds to a rotation angle of 180.

In detail, when the x-ray generator 106 projects x-rays in the direction of the object 1801 for the first time T1, the x-ray projected in the x-ray projection direction 1832 passes through the object 1813, whereby a signal 1831 can be obtained. The value of the signal 1831 can be changed to the surface of the object 1813 due to differences in the permeability of x-ray radiation in accordance with the material of the object 1813. In detail, the value of the signal 1831 may vary on the surface, accommodating hydrochloric a direction parallel to the X-ray projection 1832.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1801 at the third time T12, the x-ray projected in the x-ray projection direction 1834 passes through the object 1814, whereby a signal 1833 can be obtained. The value of the signal 1833 may vary on a surface placed in a direction parallel to the X-ray projection direction 1834.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1801 at the fourth time T13, the x-ray projected in the x-ray projection direction 1836 passes through the object 1815, whereby a signal 1835 can be obtained. The value of the signal 1835 may vary on a surface placed in a direction parallel to the X-ray projection direction 1836.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1801 at the fifth time T14, the x-ray projected in the x-ray projection direction 1838 passes through the object 1816, whereby a signal 1837 can be obtained. The value of the signal 1837 can change on a surface placed in a direction parallel to the X-ray projection direction 1838.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1801 at the second time T2, the x-ray projected in the x-ray projection direction 1824 passes through the object 1817, whereby a signal 1839 can be obtained. The value of the signal 1839 can vary on a surface placed in a direction parallel to the X-ray projection direction 1824.

In addition, since the signal 1831 contains information about the surface located in the X-ray projection direction 1832, an image 1851 obtained by performing reverse projection with filtering on the signal 1831 contributes to the visualization of the surface located in the X-ray projection direction 1832. In addition, since the signal 1833 contains information about the surface located in the X-ray projection direction 1834, the filtered projection data corresponding to the 1833 signal contributes to the visualization of the surface located in the X-ray projection direction 1834. In other words, the projection data obtained in each projection contribute to the visualization of the surface of the object corresponding to each projection. This can be explained by applying the central section theorem, showing the relationship between the image frequency component and the value of the projection data obtained by projecting a parallel beam to the object 1801. The "projection" corresponds to the direction, position and / or angle of rotation when the x-ray generator 106 projects the x-ray radiation towards the object.

In addition, DAS 116 of FIG. 4 may receive a signal, such as signal 1831. The image processing unit may process signal 1831 and generate filtered projection data. The filtered projection data is rear-projected, resulting in an image of 1851.

In detail, when the X-ray generator 106 rotates and projects the X-rays in a plurality of positions or projections, resulting in a plurality of filtered projection data fragments, fragments of the filtered projection data are accumulated and reverse projected, thereby reconstructing the tomographic image. In other words, an image representing an object can be obtained by a reverse projection process in which filtered projection data is displayed on image pixels.

Turning to FIG. 18B; the surface of the circular target 1802 included in the object 1801, for the first time T1 appears on the reverse projected image 1851 corresponding to the first time T1. Fragments of the filtered projection data are accumulated and reverse projected relative to the corresponding projections obtained by rotating the X-ray generator 106 counterclockwise.

For example, a back-projected image of 1853 is obtained by accumulating and back-projecting fragments of filtered projection data obtained in an angular section having an angle of 22.5. A partial surface 1854 of the circular target 1802 in the object 1801 appears in the reverse projected image 1853.

Then, the reverse-projected image 1855 is obtained by accumulating and reverse projecting fragments of the filtered projection data obtained in an angular section having an angle of 45. A partial surface 1856 of the circular target 1802 in the object 1801 appears on the reverse-projected image 1855.

Then, the reverse projected image 1857 is obtained by accumulating and reverse projecting fragments of the filtered projection data obtained in an angular section having an angle of 98. A partial surface 1858 of the circular target 1802 in the object 1801 appears on the reverse projected image 1857.

Then, the reverse-projected image 1859 is obtained by accumulating and reverse projecting fragments of the filtered projection data obtained in an angular section having an angle of 180. The entire surface 1864 of the circular target 1802 in the object 1801 appears on the reverse-projected image 1859.

For an object that does not move, the state, for example, at least one of the size, position and shape of the object 1801, does not change when considering each of the first time T1, third time T12, fourth time T13, fifth time T14 and second time T2, which are many times included in the angular section in one cycle.

Accordingly, when reconstructing a tomographic image by accumulating fragments from reverse-projected filtering data of these fragments, the projection data corresponding to the projections included in the angular section in one cycle, since the state of the object 1801 does not change in each of the projections, does not create any fuzziness due to artifacts of movement in the back-projected image of 1859, which is the result of reconstruction.

FIG. 18C and 18D are representations for describing motion artifacts that may be generated during reconstruction of a target image indicating a moving object. In detail, 18C illustrates that the X-ray generator 106 performs tomographic scanning while rotating around an object 1805. In addition, 18D illustrates the operation of performing back projection on projection data obtained by filtering the original data obtained by tomographic scanning. In 18D, a case of reconstructing a tomographic image by a back projection filtering method is described as an example. In addition, a case in which an object 1805 includes two circular targets 1806 and 1807, illustrated in 18C, is described as an example. In the description below, for convenience of explanation, the upper circular target of the object 1805 is called the first target 1806, and the lower circular target of the object 1805 is called the second target 1807. In addition, as illustrated in FIG. 13, the angular section 1360 per cycle is an angle of 180 + the angle of a fan beam. However, at 18C, for convenience of explanation, the case of rotation through 180 and performing a tomographic scan is described as an example.

Turn to 18C; by passing the x-ray generator 106 along the original path 1810, which is circular, and projecting the x-ray radiation toward the object in each of a plurality of positions having a predetermined angular interval, projection data is obtained. The projection data is then filtered, resulting in filtered projection data. At 18C, a plurality of points located on the original path 1810 indicate the positions at which the x-ray generator 106 is located and projects the x-ray radiation. For example, when moving at a predetermined interval, such as 0.5, 1, or 3, the x-ray generator 106 can project x-rays in the direction of the object 1805. The x-ray generator 106 rotates from the first time T1 to the second time T2. Accordingly, the first time T1 corresponds to a rotation angle of 0, and the second time T2 corresponds to a rotation angle of 180 °.

Object 1805 can move as object 1820, object 1821, object 1822, object 1823, and object 1830, respectively, at first time T1, third time T12, fourth time T13, fifth time T14 and second time T2. In detail, the size of the first target 1806 included in the object 1805 expands without changing its position, while the second target 1807 does not expand, but can move from left to right.

In detail, when the x-ray generator 106 projects x-rays in the direction of the object 1805 for the first time T1, the x-radiation projected in the x-ray projection direction 1845 passes through the object 1820, whereby a signal 1840 can be obtained. The value of the signal 1840 can be changed to the surface of the object 1813 due to differences in the permeability of x-ray radiation in accordance with the material of the object 1820. In detail, the value of the signal 1840 may vary on the surface, accommodating hydrochloric a direction parallel to the X-ray projection 1845.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1805 at the third time T12, the x-ray projected in the x-ray projection direction 1846 passes through the object 1821, whereby a signal 1841 can be obtained. The value of the signal 1841 can vary on a surface placed in a direction parallel to the direction 1846 of the projection of x-ray radiation.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1805 at the fourth time T13, the x-ray projected in the direction of the x-ray projection 1847 passes through the object 1822, whereby a signal 1842 can be obtained. The value of the signal 1842 can change on a surface placed in a direction parallel to the direction 1847 of the projection of x-ray radiation.

Furthermore, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1805 at the fifth time T14, the x-ray projected in the direction of the x-ray projection 1849 passes through the object 1823, as a result of which the signal 1843 can be obtained. The value of the signal 1843 may vary on a surface placed in a direction parallel to the direction 1849 of the projection of x-ray radiation.

In addition, when the x-ray generator 106 projects the x-ray radiation in the direction of the object 1805 at the second time T2, the x-ray projected in the direction of the x-ray projection 1850 passes through the object 1830, whereby a signal 1844 can be obtained. The value of the signal 1844 can change on a surface placed in a direction parallel to the direction 1850 of the projection of x-ray radiation.

In addition, since the signal 1840 contains information about the surface located in the X-ray projection direction 1845, an image 1861 obtained by performing reverse projection with filtering on the signal 1840 contributes to the visualization of the surface located in the X-ray projection direction 1845. In addition, since the signal 1841 contains information about the surface located in the X-ray projection direction 1846, the filtered projection data corresponding to the 1841 signal contributes to the visualization of the surface located in the X-ray projection direction 1846. In other words, the projection data obtained in each projection contribute to the visualization of the surface of the object corresponding to each projection. "Projection" corresponds to the direction, position and / or angle of rotation when the x-ray generator 106 projects x-rays in the direction of the object.

In addition, DAS 116 of FIG. 4 may receive a signal, for example, a signal 1840. The image processing unit may process a signal 1840 and generate filtered projection data. The filtered projection data is rear-projected, resulting in an image of 1861.

In detail, when the X-ray generator 106 rotates and projects the X-rays in a plurality of positions or projections, resulting in a plurality of filtered projection data fragments, fragments of the filtered projection data are accumulated and reverse projected, thereby reconstructing the tomographic image. In other words, an image representing an object can be obtained by a reverse projection process in which filtered projection data is displayed on image pixels.

Turn to 18D; the surface 1862 of the first target 1811 and the surface 1863 of the second target 1812 included in the object 1820, for the first time T1 appears in the rear-projected image 1861 corresponding to the first time T1. Fragments of the filtered projection data are accumulated and reverse projected relative to the corresponding projections obtained by rotating the X-ray generator 106 counterclockwise.

For example, a back-projected image of 1865 is obtained by accumulating and back-projecting fragments of filtered projection data obtained in an angular section having an angle of 22.5. The partial surface 1866 of the first target 1806 and the partial surface 1876 of the second target 1807 in the object 1805 appears in the back-projected image 1865.

Then, the reverse projected image 1870 is obtained by accumulating and reverse projecting fragments of the filtered projection data obtained in an angular section having an angle of 45. A partial surface 1871 of the first target 1806 and a partial surface 1872 of the second target 1807 in the object 1805 appears on the reverse projected image 1870 .

Then, the reverse-projected image 1875 is obtained by accumulating and reverse projecting fragments of the filtered projection data obtained in an angular section having an angle of 150. Partial surface 1876 of the first target 1806 and partial surface 1877 of the second target 1807 in the object 1805 appears on the reverse-projected image 1875 .

Then, the back-projected image 1880 is obtained by accumulating and back-projecting fragments of the filtered projection data obtained in an angular section having an angle of 180. All surfaces of the first target 1806 and the second target 1807 in the object 1805 appear on the back-projected image 1875.

On 18D, the image 1890 is a tomographic image showing the result of reconstructing an object through a back projection process.

However, due to the movement of the object, fragments of the surface information of fragments of the filtered projection data obtained in each projection do not correspond to each other. Accordingly, when a plurality of fragments of the filtered projection data obtained in the angular section in one cycle, as illustrated in 18D, are accumulated, the surface does not appear clearly, and thus fuzziness is generated, 1881 and 1882.

According to the present invention, even when the object contains various materials, surfaces and / or shapes, such as an object 1805 with 18C, the movement of the object 1805 can be traced, and the movement of the object 1805 can be accurately estimated without imposing restrictions on the object subjected to tomographic scanning. Accordingly, an image that is motion-corrected can accordingly be reconstructed. The image reconstruction operation using the first information described above is described below in detail with respect to FIG. 19A-24.

FIG. 18E is a view for describing an object represented as a 3D tomographic image. Although the 2D tomographic image is described as an example in the above drawings, the target image can be reconstructed as a 3D tomographic image.

In detail, refer to FIG. 13C; the object can be reconstructed as a 3D tomographic image 1895. When the target image is reconstructed as a 3D tomographic image 1895, the first image and the second image are obtained as 3D tomographic images showing the object. The first image may contain information about the movement of an object in 3D.

For example, as illustrated in 18C, when an object is represented on a 3D tomographic image of 1895 as a first target 1896 and a second target 1897, the first information may contain information about the movements of the first target 1896 and the second target 1897. FIG. 19A and 19B are representations for describing a measurement of a magnitude of an object’s movement. In FIG. 19A and 19B, the first angular section 1901 and the second angular section 1902 are identical to the first angular section 1361 and the second angular section 1362 of FIG. 13, respectively. The first image 1910 and the second image 1920 correspond to the first image 1310 and the second image 1320 of FIG. 13, respectively. The MVF information 1940 is identical to the MVF information described in FIG. 13B. Accordingly, in FIG. 19A and 19B the redundant descriptions of FIG. 18A and 18B are omitted. In addition, since the object 1805 in FIG. 19A is identical to object 1805 at 18C, redundant description is omitted from 18C.

Turning to FIG. 19B; the first image 1910 is obtained using projection data corresponding to the first angular section 1901, which were obtained during the rotation of the x-ray generator 106 around the object 1805. The first image 1910 shows the surfaces 1911 and 1912 included in the first target 1806, and the surfaces 1913 and 1914 included to the second target 1807. In addition, the second image, 1920 is obtained using projection data corresponding to the second angular section 1902, which were obtained during rotation of the x-ray generator 106 around object 1805. The second image 1920 shows surfaces 1921 and 1922 included in the first target 1806, and surfaces 1923 and 1924 included in the second target 1807. In other words, projection data obtained in each projection of a predetermined angular section included in the angular section in one cycle, contribute to the visualization of various other surfaces or various other areas of the object 1805.

Since the surfaces of the same parts of the object 1805 are shown in the first image 1910 and the second image 1920, the data receiver 710 compares the first image 1910 and the second image 1920, as in image 1930, and obtains MVF 1940 indicating the movement of object 1805. MVF 1940 includes themselves vectors 1941, indicating the direction of motion and the degree (magnitude) of movement of the surface of one and the same part. Accordingly, the first information indicating the movement of the object 1805 between the first time t1 and the second time t2 can be obtained through MVF 1940.

Since the first image 1910 and the second image 1920 are images reconstructed using projection data obtained in a partial angular section, accordingly, the reconstructed image may have high temporal resolution and reduced motion artifacts. Reconstruction of the target image at the target time Ttarget using the obtained 1940 MVF is described below in detail with respect to FIG. 20A to 21C.

FIG. 20A and 20B are representations for describing a reconstruction operation of a target image. The redundant descriptions of FIG. 18A and 19B are omitted.

The image reconstructor 720 reconstructs the target image at the target time Ttarget by using information indicative of the movement of the object 1805, for example, MVF.

As described above, the first information 2080 of FIG. 20B can be obtained by using MVF1940. Since the first information is the same as the first information described in FIG. 13C, its detailed description is omitted. The degree of movement of the object 1805 at the target time can be estimated using the first information 2080. Alternatively, a state including at least one of the size, shape and position of the object 1805 at the target time Ttarget can be estimated using the first information 2080.

As described above in FIG. 19A and 19B, projection data obtained in each projection or a predetermined angular section included in the angular section in one cycle contribute to the visualization of various other surfaces or various other areas of the object 1805.

In the reconstruction process of the target image, the image reconstructor 720 may perform motion correction by using the first information on a part of the surface or area of the object 1805, which is displayed using projection data obtained at a time other than the target time Ttarget, except for a part of the surface or area of the object 1805, which is depicted using the projection data obtained at the target time Ttarget.

In FIG. 20A, for ease of explanation, the angular section in one cycle is divided into five angular sections 2001, 2002, 2003, 2004 and 2005, and images obtained by reverse projecting projection data obtained in each of the divided angular sections are illustrated. In detail, a partial image 2021 is obtained by reverse projection of the projection data obtained in the first angular section 2001. A partial image 2031 is obtained by the reverse projection of the projection data obtained in the third angular section 2002. A partial image 2041 is obtained by the reverse projection of the projection data obtained in the fourth angular section section 2003. A partial image 2051 is obtained by reverse projection of the projection data obtained in the fifth corner section ii 2004. In addition, a partial image 2061 obtained by backprojection of projection data acquired in the second angled section 2005.

In FIG. 20A, the first angular section 2001, the second angular section 2005, the partial image 2021 and the partial image 2061 correspond identically to the first angular section 1901, the second angular section 1902, the first image 1910 and the second image 1920 of FIG. 19A and 19B, respectively.

Turning to FIG. 20A; a case in which the target time Ttarget is set as the average between the first time t1 and the second time t2 is described as an example. As described in FIG. 17, when projection data obtained in an angular section adjacent to the target time Ttarget is reverse projected, only surfaces 2042, 2043, 2044 or 2045 arranged in a horizontal direction are shown in a partial image 2041. Surfaces that are not shown in a partial image 2041 are shown using projection data obtained in an angular cross-section other than the fourth angular cross-section 2003, including the target time Ttarget, in the angular cross-section for one cycle.

When rendering a surface that is not shown in the partial image 2041, the image reconstructor 720 may perform motion correction by using the first information in order to reduce fuzziness.

In detail, surfaces or partial areas shown in the partial image 2021 obtained in the first angular section 2001 are adjusted in accordance with the MVF. In other words, when considering the first information 2080, it is assumed that the magnitude W of the motion in the first angular section 2001 is 0, and the magnitude W1 of the motion of the object 1805 at the target time Ttarget 2081 is 0.5 (W1 = 0.5). Then, the surface of the object 1805 at the target time Ttarget 2081 can be accurately obtained by deforming the object 1805 included in the partial image 2021 corresponding to the first angular section 2001 by the amount of movement W equal to 0.5 (W = 0.5). Accordingly, the corrected partial image 2022 is generated by performing motion correction on the partial image 2021 based on the amount of motion 2024 generated from the start time (t = 0) to the target time Ttarget and in comparison with the total amount of motion 2023. The total value of the movement 2024 may correspond to the maximum value of the movement W equal to 1 (W = 0) in the first information 2080, and the value 2024 of the movement may correspond to the difference between the value of the movement W1 at the target time Ttarget 2081 and the value of the movement W at the time 0 (t = 0 ) corresponding to the first angular section 2001.

Motion correction is performed on other angular sections in the same way as in the first angular section. In detail, the corrected partial image 2032, which was corrected by performing motion correction on the partial image 2031 obtained by reverse projecting the projection data obtained in the third angular section 2002, based on the amount of motion 2034 generated from the third time T12 to the target time Ttarget 2081, compared with the total value of 2023 movement.

In addition, the corrected partial image 2062 is generated by performing motion correction on the partial image 2061 obtained by reverse projecting the projection data obtained in the second angular section 2005 based on the amount of motion 2064 generated from the end time (t = end) to the target time Ttarget 2081, compared with the total value of 2023 movement. In addition, the corrected partial image 2052 is generated by performing motion correction on the partial image 2051 obtained by reverse projecting the projection data obtained in the fifth angular section 2004 based on the amount of motion 2054 generated from the fifth time T14 to the target time Ttarget 2081, compared with a total value of 2023 movements.

Motion correction using projection data obtained at some time before the target time Ttarget 2081, and motion correction using projection data obtained at some time after the target time Ttarget 2081, can be performed in opposite directions. In detail, if we consider the first information 2080, the motion correction to the target time Ttarget 2081 is performed in the direction 2085, in which the amount of motion W increases, and the motion correction after the target time Ttarget 2081 is performed in the direction 2086, in which the amount of motion W decreases. Accordingly, the directions the total movement amount 2023 at the first time T1 and the total movement value 2023 at the second time T2 are illustrated as opposed to each other.

In addition, the first information includes information about the motions of the depicted surfaces in the partial image 2021 and the partial image 2061. Accordingly, the image reconstructor 720 can perform motion correction by deforming the surface or partial area of the object 1805 in a first direction that is perpendicular to the direction in which the x-ray radiation is projected in the first angular section 2001 and the second angular section 2005.

The target image corresponding to the target time Ttarget, can be reconstructed using the corrected partial images 2022, 2032, 2052 and 2062, and a partial image 2041 obtained in the fourth angular section 2003, including the target time Ttarget. Since the corrected partial images 2022, 2032, 2052, and 2062 accurately reflect the state of movement of the object 1805 at the target time Ttarget, the generation of motion artifacts can be reduced in the target image reconstructed by performing motion correction using the first information described above.

In the case when the image is reconstructed by tomographic scanning of a moving object without performing a motion correction, a strong fuzziness in a part of the surface can be generated due to projection data obtained at a time remote from the target time Ttarget. In detail, surfaces extending in a horizontal direction are depicted in a partial image 2041 obtained in a fourth angular section 2003 including a target time Ttarget 2081, and surfaces extending in a vertical direction that are not depicted in a partial image 2041 are depicted in a partial image 2021 and a partial image 2061 corresponding to the first time T1 and the second time T2, respectively, located farthest from the target time Ttarget 2081. As described above, due to the movement of the object 1805, ited depicted in a partial image 2021 resulting in a first angular section 2001 which is the initial angular cross section and a partial image 2061, resulting in a second angular section 2005, which is the final angular section, are significantly different in their positions and sizes. In other words, fuzziness is most strongly generated in the image reconstructed using projection data obtained in the initial angular section and projection data obtained in the final angular section. Accordingly, surfaces extending in the vertical direction on the target image Ttarget 2081 are blurred due to surfaces having different positions and sizes and are shown in the partial image 2021 and the partial image 2061. In detail, when the average time between the first time T1 and the second time T2 set as the target time Ttarget, as illustrated at 18C, fuzziness 1881 and 1882 are most strongly generated on surfaces extending in the vertical direction on the reverse projection vaniyu image 1880 which is the target image, as 18D.

In one embodiment, the image reconstructor 720 may generate a target image 2070 by performing motion correction on partial images obtained in an angular section in one cycle by using the first information, and thus, motion artifacts can be reduced.

In addition, when the target time Ttarget 2081 is set in the middle between the first time T1 and the second time T2, which are the start time and the end time of the angular section in one cycle, motion correction can be effectively performed on surfaces 1881 and 1882, where the fuzziness is most strongly generated in the image reconstructed in accordance with the target time Ttarget 2081, and as a result, motion artifacts in the reconstructed image can be reduced. Accordingly, the target time Ttarget can be set in the middle of the time of the angular section in one cycle, and motion correction can be performed by using the first information, as a result of which the target image having optimized image quality is built.

In detail, since the first information is obtained by using the partial image 2021 and the partial image 2061, which are generated using projection data obtained in each of the first angular section 2001 and the second angular section 2005, the first information most accurately includes motion information, for example, surface components 2025, 2026, 2027, and 2028 and 2065, 2066, 2067 and 2068, respectively, included in the partial image 2021 and the partial image 2061. Accordingly, the motion correction may be but it is formed on surfaces of components 2025, 2026, 2027 and 2028 and 2065, 2066, 2067 and 2068 which are arranged vertically with respect to the object 1805 by performing motion correction based on the first information. However, in the first information, information about the movements of surface components, included, for example, in a partial image 2031, 2041 or 2051, generated on the basis of projection data obtained in a projection included in a section other than the first angular section 2001 and the second angular section 2005, may be less accurate than information about the movements of the components of the surfaces 2025, 2026, 2027 and 2028, and 2065, 2066, 2067 and 2068, respectively, included in the partial image 2021 and the partial image 2061.

In detail, surface motions detected in the first angular section 2001 and second angular section 2005, which, respectively, are the initial cross-section and the final cross-section of the angular cross-section in one cycle, have the lowest correlation with the motion of the surface detected in the angular cross-section, for example, the fourth angular section 2003, which is orthogonal to the first angular section 2001 and the second angular section 2005. Accordingly, among the information about the movement of the surface of the object according to the first information, it may turn out that the ridge will be the largest in the information about the movement of the surface component included in the image, for example, partial image 2041 generated using projection data obtained in an angular section, for example, the fourth angular section 2003, which is orthogonal to the first angular section 2001 and the second angular section 2005.

When setting the target time, when the fourth time T13, which is orthogonal to the first angular section 2001 and the second angular section 2005 and is also the average time between the first angular section 2001 and the second angular section 2005, is set as the target time, there is no need to perform motion correction on a surface component, for example, surface components 2042, 2043, 2044 and 2045, depicted using projection data obtained in the fourth angular section 2003, which is an orthogon to the first angular section 2001 and the second angular section 2005. Accordingly, the influence of the error that can occur when correcting the movement of an object can be reduced by removing the error that can occur when performing motion correction on a surface component, for example, surface components 2042, 2043 , 2044 and 2045, depicted in an angular section that is orthogonal to the first angular section 2001 and the second angular section 2005. Accordingly, when the position of the target time Ttarget is located in the middle field zhenii between a first angular section 2001 and the second angled section 2005, the quality of the reconstructed target image can be improved.

Furthermore, although FIG. 20A illustrates a case in which the angular section in one cycle is divided into a plurality of angular sections, and motion correction is performed for each of the rear projection images corresponding to the angular sections, as an example. In addition, motion correction can be performed on a partial image obtained by reverse projection of the projection data obtained in each projection included in the angular section in one cycle. Also, motion correction can be performed during the reverse projection of the projection data obtained in each projection. In addition, motion correction can be performed on a partial image obtained by reverse projection of the projection data obtained in a projection group including several projections. Also, motion correction can be performed during the reverse projection of the projection data obtained in the projection group.

Furthermore, although FIG. 20A illustrates a case of performing motion correction on partial images, motion correction can be performed on projection data corresponding to each projection, and the target image can be reconstructed by performing back projection with filtering on the corrected projection data corresponding to each projection.

FIG. 2 ° C is a reconstructed target image. Turning to FIG. 20C; the object contains two circular targets 2071 and 2072. The circular targets 2071 and 2072 correspond to the first target 1806 and the second target 1807, respectively, included in the object 1805 illustrated in FIG. 20A. Turning to FIG. 20C; the target image 2070 reconstructed by the image reconstructor 720 according to one embodiment of the present invention shows an object when the target time Ttarget is the average time between the first time t1 and the second time t2.

The target 2070 image has virtually no fuzziness due to motion artifacts and accurately reflects the state of the object at the target time Ttarget.

FIG. 21A is another view for describing a reconstruction operation of a target image.

Turning to FIG. 21A; the redundant description of FIG. 20A, because most parts are almost the same as parts in FIG. 20A, except that a time that is not an average angular section time per cycle is set as the target time Ttarget.

Turning to FIG. 21A; a time, for example, a third time T12, which is not an average angular section time per cycle, is set as the target time Ttarget.

Turning to FIG. 21A; the corrected partial image 2122 is generated by performing motion correction on the partial image 2121, based on the motion value 2124 generated from the start time (t = 0) to the target time Ttarget, compared to the total motion value 2123. The total magnitude of the motion 2123 corresponds to the magnitude of the motion W, which is 1 (W = 1) in the first information 2180 shown in FIG. 21B. The magnitude 2124 of the movement corresponds to the difference between the magnitude of the motion W at the start (t = 0) and the magnitude of the motion W2 at the target time Ttarget 2181.

Motion correction is performed on other angular sections in the same way as in the first angular section. In detail, the corrected partial image 2142 is generated by performing motion correction on the partial image 2141, based on the amount of motion 2144 generated from the fourth time T13 to the target time Ttarget, compared with the total value 2123 of the movement.

In addition, the corrected partial image 2152 is generated by performing motion correction on the partial image 2151 based on the amount of motion 2154 generated from the fifth time T14 to the target time Ttarget, compared with the total value 2123 of the movement. In addition, the corrected partial image 2162 is generated by performing motion correction on the partial image 2161, based on the amount of motion 2164 generated from the end time (t = end) to the target time Ttarget, compared with the total value 2123 of the movement.

The target image corresponding to the target time Ttarget can be reconstructed by using the corrected partial images 2122, 2142, 2152 and 2162, and the partial image 2131 obtained in the third angular section 2002, including the target time Ttarget.

FIG. 21C is a reconstructed target image.

Turning to FIG. 21C, the target image 2170 reconstructed by the image reconstructor 720 according to one embodiment of the present invention shows an object for the case where the target time Ttarget is not the average time between the first time t1 and the second time t2, as illustrated in FIG. 21A.

Target image 2170 has virtually no fuzziness due to motion artifacts.

However, the quality of the target image 2170 reconstructed in the case when the target time Ttarget is not the average time between the first time t1 and the second time t2 may be lower than the quality of the target image 2070 reconstructed when the target time Ttarget is the average time between the first time t1 and second time t2. For example, when the target image 2170 and the image 2070 are compared with each other, it can be seen that the shapes of the first target 2171 and the second target 2172 included in the object are partially deformed. In detail, in the target image 2170, the shape of the lower surface of the first target 2171 looks a little distorted.

In other words, in the target image, the degree of motion correction of the object included in the target image may vary according to the target time Ttarget. In detail, as the target time Ttarget approaches the average time between the first time t1 and the second time t2, the motion correction is performed better and thus the target image can become an image better reflecting the state of the object at the target time Ttarget. In contrast, when the target time Ttarget is not the average time between the first time t1 and the second time t2, the motion correction is poorly performed and thus the target image may not accurately reflect the state of the object at the target time Ttarget compared to the case in which the target time Ttarget is the average time between the first time t1 and the second time t2.

Accordingly, in the reconstructed target image, object movement correction can be performed better when the target time Ttarget corresponds to the average time between the first time t1 and the second time t2, compared with the case in which the target time Ttarget does not correspond to the average time between the first time t1 and the second time t2.

From the point of view of image quality, the quality of the reconstructed image can change in accordance with the position or projection in the angular section in one cycle for which the target time Ttarget is set. “Image quality” may vary according to how clearly the image shows the state of the object at a particular time. For example, image quality may correspond to the degree of deformation of an object. In addition, for example, we can say that an image that accurately reflects the state of an object at a certain time has superior image quality. On the contrary, it can be said that an image that does not accurately reflect the state of an object at a certain time so that at least one of the position, shape and size of the object differs from similar parameters of the object at a certain time has poor image quality. In detail, as illustrated in FIG. 2 ° C and 21C, the quality of the reconstructed image is optimal when the target time is the average time between the first time t1 and the second time t2.

FIG. 22A and 22B are views for describing a warping operation used to reconstruct a target image.

To reconstruct the target image, the image reconstructor 720 performs a reverse projection, that is, it reflects the filtered projection data obtained in a plurality of projections included in the angular section for one cycle in the image area 2201 indicating the object. In the description below, reverse projection is performed on a partial area 2202 included in the image area 2201. Region 2202, as illustrated in FIG. 22A and 22B may be image data including pixel values or an image represented by pixel values. In addition, region 2202 may be an image space for rendering an object. In FIG. 22A and 22B, a case in which the filtered projection data 2210 obtained by projecting the x-ray radiation in the direction 2211 for the first time T1, which is the start time of the angular section in one cycle by the reverse projection, is described as an example. Image data included in area 2202 may be referred to as back projected projection data.

Turning to FIG. 22B, the image reconstructor 720 may deform an image grid formed of a plurality of pixels in order to visualize an object according to the amount of movement of the object at the target time Ttarget based on the first information, and may reconstruct the target image by using the deformed image grid.

In detail, refer to FIG. 22A and 22B; the filtered projection data 2210 is reflected on the image grid included in the filtered projection data 2210. The reflection of the filtered projection data 2210 onto the image grid, which is the image space, is called back projection.

Accordingly, region 2202 is populated with pixel values 2213, as illustrated in FIG. 22A. When no movement is generated by the object, motion artifacts cannot be generated on the reconstructed target image, even if the image is displayed by cumulative reflection of the filtered projection data 2210 according to each projection onto the image grid. However, when a movement is generated during an angular section in one cycle, the differences between surfaces indicating the same part of the object are generated in many fragments of the filtered projection data obtained in each projection. Accordingly, when the filtered projection data 2210 according to each projection is cumulatively reflected on the image grid in order to render the image, motion artifacts can be generated on the reconstructed target image.

In the present embodiment, in order to reduce motion artifacts of a moving object, a motion correction is performed as described with respect to FIG. 20A and 21A. In the description below, deformation of the image grid by the image reconstructor 720 for the purpose of motion correction is described in detail.

The image reconstructor 720 deforms the image grid 2230 to render the same part as the area 2202, according to the MVF indicating the amount of movement of the object to the target time Ttarget in the area 2202 by using first information, for example, MVF information indicating the movement of the object. For example, the upper left region on the image grid 2230 may be deformed according to vectors 1941.

Then, an image grid 2240 is obtained, obtained by deformation of the image grid 2230. The image reconstructor 720 reflects the pixel values included in the filtered projection data 2210 onto the image grid 2240 that has been deformed. Accordingly, pixel values are included in a region 2235 that is identical to a region 2202, as illustrated in FIG. 22B. In region 2235, a rectangular image grid 2241, represented as a dotted grid, indicates a common image grid that has not been deformed.

Then, the image reconstructor 720 resamples the region 2235 containing the pixel values according to the deformed image grid 2240 to the region 2245 containing the pixel values according to the rectangular image grid 2241. In detail, pixel values according to the deformed image grid 2240 are interpolated by using a quadratic pixel image matrix and converted to pixel values according to Cartesian coordinates.

In the description below, the case of resampling the pixel values of pixels 2242 and 2243 included in the deformed image grid 2240 to the pixel value 2254 included in the rectangular image grid 2241 is described as an example. The pixel 2242 included in the deformed image grid 2240 has a signal value of "2", and the pixel 2243 has a signal value of "1". In other words, since the value of the image signal included in the entire region of the pixel 2242 is 2, the value of the signal “2” is included in the pixel 2242 by distribution at the expansion degree of the pixel 2242. Accordingly, the value of the signal “1” can be included in the partial region 2261 corresponding to half of the entire region of the pixel 2242. In addition, since the value of the image signal included in the entire region of the pixel 2243 is 1, the value of the signal “1” is included in the pixel 2243 by distribution at the expansion degree of the pixel 2243. Corresponding Naturally, the signal value “0.5” can be included in the partial region 2262 corresponding to half of the entire region of the pixel 2243. In addition, the signal value “1.5”, which is the sum of the signal value “1” from the partial region 2261 and the value the signal "0.5" from the partial region 2262, can be included in the pixel 2254 according to the rectangular grid 2241 and 2251 of the image, including the partial region 2261 and the partial region 2262.

Accordingly, the pixel values 2255 are located in the oversampling area 2245 according to the rectangular image grid 2251. Accordingly, the pixel values 2255 included in the region 2245 can be generated by oversampling all the pixel values included in the region 2235.

In addition, in addition to the above method, various methods can be applied as a method of converting pixel values arranged according to a deformed image grid to pixel values arranged according to a rectangular image grid.

In addition, motion correction can be performed by applying deformation relative to each of all fragments of the projected projection data corresponding to the plurality of projections included in the angular section in one cycle. The target image can be reconstructed by accumulating back-projected projection data on which motion correction is performed.

In addition, motion correction by deforming the image grid may not be performed for each projection, but motion correction may be performed for each group for a predetermined angular section including multiple projections.

As in the above example, the image reconstructor 720 may generate motion-corrected image data 2270 by using an image grid deformed based on the first information.

FIG. 23A and 23B are views for describing a warping operation used to reconstruct a target image. In FIG. 23A and 23B the redundant description of FIG. 22A and 22B are omitted.

In detail, the image reconstructor 720 may generate a motion-corrected target image by deforming the reverse projected image according to the first information. In detail, in the back projection process, the image reconstructor 720 can reconstruct the target image by deforming the pixel corresponding to the data obtained by tomographic scanning based on the first information. In detail, the image reconstructor 720 may warp the pixel based on the amount of movement of the object at the target time Ttarget according to the MVF.

Turning to FIG. 23A and 23B; image pixels (or image data) 2330 generated by reverse projecting the filtered projection data 2210 are deformed based on the MVF information 1940. Accordingly, pixel values 2331 included in the image 2330 are generated in the deformed image 2335 corresponding to the object at the target time Ttarget, Founded 1941 MVF. In detail, the pixel value “2” of the filtered projection data 2311 corresponds to the pixel value “2” 2336 in the third column of the deformed image 2335. The pixel value “2” of the filtered projection data 2312 corresponds to the pixel values “2” 2337 in the fourth column of the deformed image 2335.

The deformed image 2335 generates a motion-corrected image 2355 by oversampling in the method described in FIG. 22B. The pixel values 2356 included in the motion-corrected image 2355 accurately reflect the movement of the object at the target time Ttarget. Accordingly, motion artifacts in the resulting reconstructed target image can be reduced.

FIG. 24A and 24B are views for describing a reconstruction operation of a target image. In FIG. 24A and 24B the redundant descriptions of FIG. 22A-23B are omitted. The image reconstructor 720 may perform motion correction in the reverse projection process based on the first information. In detail, the image reconstructor 720 may deform the center of the voxel indicating the object based on the first information, and may reconstruct the target image by reverse projecting the position of the deformed voxel. A voxel indicates one unit of space in a virtual 3D mesh space to render an object. In FIG. 24A and 24B, a case in which a virtual 3D mesh space for displaying an object is illustrated using pixels forming a 2D mesh space, instead of voxels forming a 3D mesh space, is illustrated as an example.

In detail, the image reconstructor 720 can find which of the pixel values in the plurality of detectors should be indicated by using MVF from the target time Ttarget until each time that the pixel value at a predetermined position in the image to be reconstructed is affected by movement to each of moments of time. Given the voxel indicating the object at the target time Ttarget, in order to reverse project the filtered projection data in a projection other than the target time Ttarget in the direction of the voxel, the voxel destination to which the voxel moves at the appropriate time is calculated by reflecting the movement object. The magnitude of the voxel movement to correct the movement of the object can be calculated by using the inverse MVF for the MVF from the corresponding time to the target time Ttarget. The pixel value in the plurality of detectors to be used after moving the voxel position according to the calculated correction amount can be calculated.

In detail, refer to FIG. 24A and 24B; the image reconstructor 720 performs a field inversion on an MVF indicating the magnitude of the object’s movement at the target time Ttarget, and generates an inverted field MVF 2410. The position of each pixel on the reverse projected image 2420 is moved by using the inverted field MVF 2410.

For example, the positions of the pixels in the back projected image 2420 are moved based on the motion vectors 2411, 2421, 2422 and 2423 included in the inverted field of the MVF 2410. In detail, the pixel in the first row and the sixth column in the back projected image 2420 moves in accordance with the arrow 2431 based on vector 2421 and vector 2422. A pixel in the fifth row and sixth column of the reverse projected image 2420 moves in accordance with arrow 2432 based on the motion vector 2423. In addition, the position of the pixel in region 2427 of the inverted field of MVF 2410, where no movement was detected, remains the same.

Then, the image reconstructor 720 calculates which position of the plurality of detectors corresponds to the pixel value in the specific pixel when the pixel value of the specific pixel is projected based on the moved position of the pixel, and takes the filtered projection data 2210 at the calculated position to accumulate the value in the specific pixel, thereby obtaining reverse projected image 2420.

For example, if we consider the displaced position 2431, the center of the pixel 2451 in the first row and sixth column in the reverse projected image 2450 is obtained by using the pixel value at position P1 in the filtered projection data 2210. The position P1 is not located in the center of the pixel 2456 in the first row and sixth column in the filtered projection data 2210, but is located close to the pixel 2455 in the first row and fifth column, as a result of which it is affected by the pixel 2456 and pixel 2455. Accordingly, the pixel 2451 may have a value of “0.2” since it is affected by a pixel 2456 having a value of “0” and a pixel 2455 having a value of “1”, as illustrated in FIG. 24B.

Furthermore, likewise, the center of the pixel 2452 in the fifth column and the sixth column in the reverse projected image 2450 is located on the surface of the pixel 2452 and the pixel 2457, which are adjacent to each other, in accordance with the movement of the pixel 2432, as illustrated in FIG. 24B. Accordingly, the pixel 2451 is affected by the pixel 2456 and the pixel 2455. Accordingly, the pixel 2451 may have a value of “0.5”, which is the average value between the pixel 2456 having a value of “0” and the pixel 2455 having a value of “1”.

As described above, the image reconstructor 720 may obtain a motion-corrected target image 2470, which is a motion-corrected rear-projected image, by deforming the voxel by applying the inverted MVF field, and not by applying the deformation described in relation to FIG. 22A-23B.

FIG. 25A and 25B are views for describing reconstructed target images. FIG. 25A illustrates a tomographic image 2510 obtained by the half reconstruction method described in relation to FIG. 18A-18E. FIG. 25B illustrates a tomographic image 2560, which is corrected for movement by using the first information according to one embodiment of the present invention. In addition, FIG. 25B illustrates a tomographic image of 2560 when the target time Ttarget is the average time between the first time t1 and the second time t2.

Turning to FIG. 25A; blurring 2511 and 2512 are generated in the first target 2501 of the object included in the tomographic image 2510, and blurring 2521 and 2522 are generated in the second target 2502.

In contrast, referring to FIG. 25B, in the tomographic image 2560 reconstructed in the tomographic apparatus 700 according to one embodiment of the present invention, it can be seen that no fuzziness is generated in the first target 2501 and the second target 2502.

FIG. 26 is a view for describing a measurement of the magnitude of an object's movement

When the data receiver 710 receives the first image and the second image, since the value of “a” in the first angular section and the second angular section increases, the temporal resolutions of the first image and the second image may be degraded.

In order to prevent deterioration in the temporal resolution of the first image and the second image when the tomographic scan is performed by projecting the x-ray radiation while the x-ray generator 106 is rotated around the object according to the half reconstruction method, a plurality of images are obtained in a plurality of angular sections included in the first “a "Angular section 2611, which is the initial additional angular section of the angular section in one cycle, and many images of the floor take into account the set of angular sections included in the last "a" angular section 2612, which is the last additional angular section of the angular section in one cycle. The first information can be obtained by using the obtained images. In FIG. 26 is a case in which each first “a” corner section 2611 corresponding to the first corner section 1411 of FIG. 14, and the last “a” corner section 2612 corresponding to the second corner section 1412 of FIG. 14, divided into two angular sections, illustrated as an example.

Turning to FIG. 26; the data receiver 710 obtains a first image and a third image, respectively, in a first angular section 2621 and a third angular section 2631, which are included in the first “a” angular section 2611 of the angular section in one cycle having an angle of 180 + a. The first angular section 2621 may correspond to the first "a / 2" of the first "a" angular section 2611, and the third angular section 2631 may correspond to the last "a / 2" of the first "a" angular section 2611. The data receiver 710 receives a second image and a fourth image respectively, in the second angular section 2622 and the fourth angular section 2632, which are included in the last “a” angular section 2612 of the angular section in one cycle. The second angular section 2622 may correspond to the first "a / 2" of the last "a" angular section 2612, and the fourth angular section 2632 may correspond to the last "a / 2" of the last "a" angular section 2612. The first information indicating the relationship between time and value the movement of the object can be obtained based on the amount of movement between the first image and the second image and the amount of movement between the third image and the fourth image. The first angular section 2621 and the second angular section 2622 are angular sections having a paired angle ratio. The third angular section 2631 and the fourth angular section 2632 are angular sections having a paired angle ratio.

In addition, the data receiver 710 can divide each of the first “a” corner section 2621 and the last “a” corner section 2612 into three or more corner sections, and can obtain the first information by using an image reconstructed from each of the corner sections.

Since the generation of the first information by using these two images obtained in two angular sections having a paired angle ratio has already been described with respect to FIG. 13, a detailed description of this is omitted.

FIG. 27 is a view for describing motion artifacts existing in a reconstructed tomographic image.

Turning to FIG. 27; block 2701 illustrates tomographic images reconstructed by a tomographic apparatus of the prior art, and block 2705 illustrates tomographic images reconstructed by tomographic apparatuses 600 and 700 according to embodiments of the present invention.

Turning to a tomographic image of a cross section 2710 of a block 2701; motion artifacts are generated due to the movement of the coronary artery 2711 in the part where the coronary artery 2711 is displayed, and as a result, the image is blurry. In addition, fuzziness is generated on surface 2712 due to organ movement.

In addition, in the cross-section tomography image 2720, fuzziness is generated in the horizontal section 2721 of the blood vessel including the coronary artery 2711, as a result of which the blood vessel is not reconstructed clearly. In addition, in the cross-section tomographic image 2730, fuzziness is generated in a portion 2731 where a blood vessel including a coronary artery 2711 is displayed, as a result of which the blood vessel is not reconstructed clearly.

In contrast, in the tomographic image 2750 of the cross section reconstructed in the tomographic apparatuses 600 and 700 according to the embodiments of the present invention, the part where the coronary artery 2751 is displayed is reconstructed clearly, and thus, the organ surface 2752 is reconstructed clearly.

In addition, in the cross-section tomography image 2760, the horizontal cross section 2761 of the blood vessel including the coronary artery 2751 is clearly reconstructed, and in the cross-section tomography image 2770, where the blood vessel including the coronary artery 2751 is displayed, it is clearly reconstructed.

As described above, in one embodiment of the present invention, a first image and a second image having a high temporal resolution can be obtained by obtaining a first image and a second image in partial angular sections included in the angular section in one cycle. Since the magnitude of the movement of the object is measured by using the first image and the second image having a temporal resolution, the first information indicating the relationship between time and the magnitude of the movement of the object can more accurately reflect the change in the movement of the object. Furthermore, since the image at the target time Ttarget is reconstructed using the first information, an image having reduced motion artifacts can be reconstructed.

FIG. 28 is a view for describing motion artifacts existing in a reconstructed tomographic image.

Turning to FIG. 28; for the case where the relative time indicating the time between the peaks of the R-R ECG is expressed as a percentage (%), tomographic images are reconstructed using relative times of 0%, 20% and 40% as the target time Ttarget. For example, if the time between R-R peaks is 0.2 seconds, then the relative time is 0.2 seconds, and 20% of the relative time is (0.2 * 20/100) = 0.04 seconds. In detail, block 2810 illustrates tomographic images reconstructed by a tomographic apparatus of the prior art, and block 2850 illustrates tomographic images reconstructed by tomographic apparatuses 600 and 700 according to one embodiment of the present invention. In the description below, tomographic images included in block 2810 are called “prior art tomographic images”, and tomographic images included in block 2850 are called “tomographic images of the present invention”.

Turning to FIG. 28; when the tomographic image 2820 of the prior art and the tomographic image 2860 of the present invention are compared with each other at a time when the relative time is 0%, a plurality of areas 2821 and 2822 where blurring is generated due to motion artifacts is present in the tomographic image 2830 of the prior art, while in the tomographic image 2860 of the present invention, motion artifacts are significantly reduced in regions 2861 and 2862, identical to the corresponding regions 2821 and 2822, in which no definition.

In addition, when the prior art tomographic image 2830 and the present tomographic image 2870 are compared with each other at a time when the relative time is 20%, the region 2831 where the blur is generated due to motion artifacts is present in the prior art tomographic image 2830, whereas in the tomographic image 2870 of the present invention, motion artifacts are significantly reduced in the region 2871, identical to the corresponding region 2831 in which the fuzziness was generated.

In addition, when the prior art tomographic image 2840 and the present tomographic image 2880 are compared with each other at a time when the relative time is 40%, a plurality of regions 2841 where blurring is generated due to motion artifacts is present in the prior art tomographic image 2840 whereas in the tomographic image 2880 of the present invention, the artifacts of movement are significantly reduced in the area 2881, identical to the corresponding area 2841, in which nothing was generated bone.

FIG. 29A and 29B illustrate user interface screens displayed on a tomographic apparatus according to embodiments of the present invention.

Turning to FIG. 29A; a display device 740 displays a user interface screen 2900 for setting first information. In detail, the user interface screen 2900 contains a first menu 2930 for setting the relationship between time and the amount of movement of an object in the first information.

In addition, the user interface screen 2900 may also include a second menu 2901 for displaying the first information. Since the first information displayed in the second menu 2901 is identical to the first information 1380 described with respect to FIG. 13C, the redundant description of FIG. 13C.

The first menu 2930 may include a submenu 2935 to set the relationship between the time and the amount of movement of the object. In the submenu 2935, any of the dependencies included in the submenu 2935 can be selected, or the equation for setting the dependence can be entered directly, according to whether the dependence between time and the magnitude of the object’s motion is linear or quadratic.

In addition, the first menu 2930 may also include a second submenu 2931 for setting the angular value of the first angular section and the second angular section. Accordingly, the user can directly set the angular value of the first angular section and the second angular section by using the second submenu 2931.

In FIG. 29A, a case in which the relationship between time and the amount of movement of an object is linear in the submenu 2935 is illustrated by way of example.

In addition, the user interface 750 receives the input of second information corresponding to the relationship between the time and the magnitude of the object’s movement through the user interface screen 2900. In detail, when the user selects the “linear” item in the submenu 2935 of the screen 2900 of the user interface, the data recipient 710 generates the first information based on the second information. In the example described above, when “linear” is selected, the data receiver 710 may generate first information 2920 based on a linear relationship between the time and the amount of movement of the object.

Furthermore, although FIG. 29A and 29B illustrate a case in which the display device 740 displays the user interface screen as an example, the user interface screen used in FIG. 29A and 29B may be generated by the user interface 750 and transmitted to an external display device (not shown) that is not included in the tomography apparatus 700. Then, the external display device may display the received user interface screen and the user observing the displayed user interface screen may input information for setting the first information through the user interface 750.

In addition, FIG. 29B illustrates another example of a user interface screen for setting first information.

Turning to FIG. 29B; a display device 740 displays a user interface screen 2950 for setting first information. In detail, the user interface screen 2950 includes a first menu 2955 for setting the relationship between time and the amount of movement of an object in the first information. The second menu 2901 of FIG. 29B is identical to the second menu 2901 of FIG. 29A.

Turning to FIG. 29B; the first menu 2955 may include a first submenu 2970 for setting the relationship between the time and the amount of movement of the object. The first submenu 2970 includes at least one of items 2971, 2972, 2973 and 2974 directly displaying the first information, as illustrated in FIG. 29B.

The user can select any of the items 2971, 2972, 2973, and 2974 included in the first submenu 2970 by using the selection cursor 2982. FIG. 29B illustrates the case in which the first item 2971 is selected. Since the first item 2971 is selected, the first information 2920 can be set in the second menu 2901, as illustrated in FIG. 29B.

In addition, the first menu 2950 may also include a second submenu 2960 for setting the angular value of the first angular section and the second angular section. The second submenu 2960 includes a plurality of predetermined angular values, as illustrated in FIG. 29B. The user can select any of the angular values included in the second submenu 2960 by using the selection cursor 2981. FIG. 29B illustrates a case in which “60” is selected in the second submenu 2960 as the angular value of the first angular section and the second angular section.

In addition to the user interface screens 2900 and 2950 of FIG. 29A and 29B, user interface screens having a plurality of forms for setting first information may be generated and displayed.

In addition, the data receiver 710 can automatically set the angular value of the first angular section and the second angular section. In addition, the recipient 710 data can automatically set the graph form of the first information.

FIG. 30 is a view illustrating a user interface screen displayed on a tomographic apparatus according to one embodiment of the present invention.

Turning to FIG. thirty; a display device 740 may display a user interface screen 3000 containing a menu for setting a target time Ttarget.

Turning to FIG. thirty; the menu may include at least one of the first submenu 3020 and the second submenu 3030 for setting the target time Ttarget.

In detail, the first submenu 3020 may include an angular section in one cycle around the object 3022 in the form of coordinates, as illustrated in FIG. 30. The user can select the target time Ttarget by selecting a predetermined position or time included in the angular section for one cycle, through the first submenu 3020 by using the cursor 3021.

In addition, the second submenu 3030 may contain information indicating the angular section in one cycle, including the first information. Since the second submenu 3030 is identical to the contents illustrated in FIG. 13C, the redundant description of FIG. 13C is omitted. The user can select the target time Ttarget by selecting a predetermined position or time included in the angular section in one cycle through the second submenu 3030 by using the cursor 3031.

In addition, when both the first submenu 3020 and the second submenu 3030 are displayed by including the user interface in the screen 3000, and the target time Ttarget is selected by using, for example, the cursor 3021 in the first submenu 3020, the cursor 3031 in the second submenu 3030 can be displayed in the position corresponding to the selected target time. Also, the target time Ttarget can be selected by using the cursor 3031 in the second submenu 3030, and the cursor 3021 in the first submenu 3020 can be displayed at the position corresponding to the selected target time.

In addition, the user interface screen 3000 may display the target image 3010 corresponding to the selected target time.

Accordingly, the user can easily set the target time by using the screen 3000 of the user interface. When an unclear surface or image error is present on the reconstructed target image 3010, the user can observe the reconstructed target image 3010 included in the user interface screen 3000 and reset the target time. Accordingly, the target image 3010, in which the blurred surface or image error is reduced, can be reconstructed again.

FIG. 31A and 31B are views illustrating a user interface screen shown on a tomography apparatus according to one embodiment of the present invention. In detail, FIG. 31A is a view for describing an installation of a study area (ROI). FIG. 31B illustrates a configuration for setting a position or viewing angle of a first angular section and a second angular section in accordance with a set ROI.

A display device 740 may display a medical image. The medical image may be various medical images, such as a preliminary x-ray, tomographic image, MRI image, x-ray image or ultrasound image.

The user can set a predefined area of the medical image as an ROI through the user interface 750.

Turning to FIG. 31A; a tomographic image 3110 of a cross section is illustrated as an example of a medical image 3100 displayed on a display device 740.

The user can set the ROI through the user interface 750. In addition, the data recipient 710 can automatically retrieve the part that needs to accurately interpret the image, such as the suspected area of the disease in the medical image, and can set the extracted part as the ROI.

The data receiver 710 can retrieve the surface included in the ROI, and can set the first angular section and the second angular section based on the direction of the extracted surface. In detail, the data receiver 710 can retrieve the surfaces 3171 and 3172 included in the ROI, and can obtain a viewing angle corresponding to the extracted area. At least one of the first angular section, the second angular section, the position of the beginning of the angular section in one cycle, the position of the end of the angular section in one cycle and the target time are set in accordance with the obtained viewing angle, and the first image and second image can be obtained, respectively in a first angular section and a second angular section corresponding to the configuration described above.

As described with respect to FIG. 16 and 17, the direction of the surface, which is clearly selected, changes according to the direction in which the x-ray irradiation occurs. Accordingly, the surfaces included in the ROI 3120 can be more clearly selected by adjusting the direction of the x-ray beam according to the direction of the surface included in the ROI 3120.

In detail, refer to FIG. 31B; the data receiver 710 can set directions 3161 and 3162 corresponding to the surfaces 3171 and 3172 included in the ROI 3120, or the viewing angle of the x-ray generator 106. The positions of the first angular section and the second angular section are set in accordance with the established direction or viewing angle. For example, when the directions in which surfaces 3171 and 3172 extend are directions 3161 and 3162, the first angular section 3151 and the second angular section 3152 can be set to correspond to directions 3161 and 3162. Accordingly, the first image is obtained by projecting x-rays from the left side ROI 3120, and the second image can be obtained by projecting x-rays on the right side of the ROI 3120.

The data receiver 710 can generate the first information by using the first image and the second image.

As described above, when the first angular section 3151 and the second angular section 3152 are set based on the directions of the surfaces 3171 and 3172 included in the ROI 3120, the surfaces 3171 and 3172 included in the ROI 3120 can be more clearly selected, resulting in the quality of the reconstructed image could be improved.

In addition, the image reconstructor 720 may set at least one of the first angular section, the second angular section, the initial part of the angular section in one cycle (angular position corresponding to t = 0), the position of the end of the angular section in one cycle (angular position corresponding to t = end) and the target time Ttarget, taking into account the direction in which the object is moving. For example, the first angular section and the second angular section can be set so that a motion measurement can be possible with respect to the direction in which many object motions are generated.

When the object is a human, and the tomographic image to be obtained is a cross-sectional tomographic image, as illustrated in FIG. 31A, for example, many movements are generated in two directions, as illustrated by the double-sided arrow 3330 along the front and rear sides of a person, due to breathing or a heart beat in a person.

In detail, many motions are generated in the 3330 direction, and in order to observe the motions in the 3330 direction in the best way, a surface, for example, a surface 3171 extending in a direction perpendicular to the 3330 direction, or in a direction adjacent to the direction perpendicular to the 3330 direction depicted. In other words, when many movements of the direction 3330 are generated, the surface 3171 is clearly depicted in the first image and the second image, which are used to obtain the first information. Since the first information is obtained by comparing the surface 3171 shown in the first image and the surface 3171 shown in the second image, the magnitude of the movement of the object in the direction 3330 can be accurately identified.

Accordingly, in order to measure the magnitude of the movement of the object in the direction 3330, the first angular section and the second angular section can be set as the first angular section 3181 and the second angular section 3182. Then, the first information regarding the movement of the object in the first direction 3183 (the same as the direction 3330) perpendicular to the directions 3161 and 3162 in which the x-ray radiation is projected in the first angular section 3181 and the second angular section 3182 can be obtained. When the motion correction is performed by applying the magnitude of the motion relative to the first direction 3183, the target image corresponding to the target time Ttarget can also be reconstructed.

In addition, the tomographic apparatus 700 may perform the following operations.

The data receiver 710 reconstructs at least one reference image for evaluating the movement of an object by performing a tomographic scan when rotating in an angular section smaller than one revolution of the object, and obtains first information indicating the magnitude of the movement of the object. An “angular cross section of less than one revolution” may identically correspond to the angular cross section described above in one cycle. In addition, at least one reference image may be a partial angular image obtained in a partial angular section included in the angular section in one cycle. In detail, the reference image may be at least one of the first image 1310 and the second image 1320, which are described in FIG. 13. In addition, the reference image may be at least one of the first image and the third image obtained in the first angular section 2621 and the third angular section 2631, respectively, and the second image and the fourth image obtained in the second angular section 2622 and the fourth angular section 2632, respectively, which are described with respect to FIG. 26.

In detail, the data receiver 710 obtains a first image corresponding to a first time, and obtains a second image corresponding to a second time through the PAR method. The first information indicates the relationship between time and the amount of movement of the object based on the amount of movement between the first image and the second image.

The image reconstructor 720 performs the motion correction operation described above to reconstruct the target image having reduced motion artifacts corresponding to the target time Ttarget in one cycle by using the first information received by the data receiver 710.

In addition, the tomographic apparatus 700 may perform the following operation.

The data receiver 710 obtains a first image and a second image corresponding to the first time and the second time, respectively, and indicating parts of the surfaces forming the object by performing a tomographic scan of the object. A data receiver 710 obtains first information indicative of the movement of an object by using the acquired first image and second image. The first information may indicate a relationship between time and the amount of movement of the surface forming the object corresponding to the MVF between the first image and the second image.

The image reconstructor 720 reconstructs the target image by using the first information.

In addition, the tomographic apparatus 700 may perform the following operation.

The data receiver 710 performs a tomographic scan on a moving object and obtains a first partial image and a second partial image using data obtained in the initial angular section and the final angular section opposite to the initial angular section, respectively. The data receiver 710 obtains first information indicating a relationship between time and the magnitude of the surface movement of the object corresponding to the MVF between the first partial image and the second partial image.

The image reconstructor 720 reconstructs the target image indicating the object at the target time Ttarget, based on the first information.

In addition, the tomographic apparatus 700 may perform the following operation.

The data receiver 710 performs a tomographic scan of the object, obtains a first image and a second image corresponding to the first time and second time, respectively, and indicating portions of the surface forming the object, and obtains first information indicating the movement of the object by using the first image and the second image. The image reconstructor 720 reconstructs the target image indicating the object by deforming at least one of the source data necessary for the half reconstruction method and the image obtained by reverse projection with filtering the source data based on the first information.

In addition, the tomographic apparatus 700 may perform the following operation.

The data receiver 710 obtains a first image and a second image, which are partial images, using data obtained in each of the first angular section corresponding to the first observation point and the second angular section corresponding to the second observation point and opposite the first angular section, by performing tomographic scan of an object. A data receiver 710 may receive first information indicating an amount of movement of an object based on a first image, a second image, and additional information.

An image reconstructor 720 reconstructs a target image indicating an object at a target time based on the first information.

In detail, when performing a tomographic scan of an object, even when the object does not move by itself, the object may have motion due to external factors. For example, when vibrations, movements or vibrations occur in the table on which the object is located, and / or in a tomographic apparatus that can generate movements in the object, the object can oscillate, move or vibrate. The generation of the movement of an object due to external factors can cause fuzzy visualization of the object.

When fuzziness occurs during the visualization of an object due to external factors, as described above, the data receiver 710 can obtain a first image, a second image and first information, and remove fuzziness during visualization of the object resulting from external factors.

In addition, the tomographic apparatus 700 may perform the following operation.

The data receiver 710 obtains a first image and a second image, which are partial images, using data obtained in each of the first angular section corresponding to the first observation point and the second angular section corresponding to the second observation point and opposite the first angular section, by performing tomographic scan of an object. The recipient 710 data may receive additional information, which is information about the movement generated in the object during tomography. A data receiver 710 may receive first information indicating an amount of movement of an object based on a first image, a second image, and additional information.

An image reconstructor 720 reconstructs a target image indicating an object at a target time based on the first information.

In detail, additional information can be used when performing a tomographic scan of an object in order to accurately predict the structure of movement of the object. For example, when the object is a heart, and the heart suddenly beats fast or beats in an unexpected pattern, additional information is obtained, which is information about the movement of heat, and the first information can be set by reflecting additional information.

In addition, when the object is not moving, and movement, such as vibrations, movements or vibrations of the tomographic apparatus, causing movement in the table on which the object is located or in the object, is generated, the movement can be generated in the object due to external factors of the object. In this case, additional information can be obtained, which is information about the movement generated in the object during tomography due to external factors, and the first information can be established by reflecting additional information.

For example, additional information can be obtained by monitoring the movement of an object undergoing tomographic scanning by using a monitoring device that monitors the movement of an object, such as a digital stethoscope. The shape of the graph can be set in the first information by reflecting the structure of the movement of an object generated in an angular section in one cycle, and obtained with a digital stethoscope. For example, when the object’s movement diagram has a linear diagram in an angular section for one cycle according to additional information, the data receiver 710 may set the first information in the form as illustrated in the first paragraph 2971 of FIG. 29. In another example, when an object moves rapidly in the initial section of the angular section in one cycle and then barely moves after the initial section of the angular section in one cycle, according to additional information, the first information can be set in the form as illustrated in paragraph 2972 on FIG. 29.

In addition, the tomographic apparatus 700 may also include a monitor (not shown) for more information. In this case, the data recipient 710 may receive additional information from the monitor and receive first information based on the additional information received. A monitor may include various types of devices for monitoring the movement of an object, for example, a digital stethoscope, a motion detection sensor, and a photosensitive sensor for motion detection.

In addition, the tomographic apparatus 700 may not include a monitor for additional information and may only use additional information received from a monitor (not shown) that is connected via an external connection.

As described above, the amount of motion generated in the angular section per cycle is measured based on the first and second images, and the structure of the object in the angular section per cycle can be set based on additional information, as a result of which the first information is obtained, more accurately indicating the movement of an object.

FIG. 32 is a flowchart for explaining a tomographic image reconstruction method 3200 according to one embodiment of the present invention. The operations of the steps included in the tomographic reconstruction method 3200 according to the present embodiment coincide with the operations of the elements included in the tomographic apparatuses 600 and 700 according to the embodiments of the present invention described with respect to FIG. 1-31. Accordingly, in the description of the tomographic image reconstruction method 3200, the redundant descriptions of FIG. 1-31 are omitted.

Turning to FIG. 32; A tomographic image reconstruction method 3200 according to an embodiment of the present invention performs a tomographic scan of an object (operation 3210). In detail, by tomographic scanning, the first image, which is a partial image, is obtained using data obtained in the first angular section corresponding to the first time, and the second image, which is a partial image, is obtained using data obtained in the second angular section, corresponding to the second time (operation 3210). Operation 3210 may be performed by the receiver 710 of the data of the tomographic apparatus 700. Each of the first angular section and the second angular section may have a value of less than 180 °.

The first information indicating the amount of movement at a time based on the amount of movement between the first image and the second image is obtained in operation 3210 (operation 3220). In detail, the first information can be obtained by comparing only the first image and the second image. Operation 3220 may be performed by the receiver 710 of the data of the tomographic apparatus 700. The first information may be the magnitude of the movement of the object at that point in time. In addition, when a moving object is scanned, the object shown in the first image and the object shown in the second image differ from each other in at least one of size, position and shape.

In detail, the first information may indicate the amount of movement of the surface forming the object. In addition, the first information may indicate the relationship between time and the amount of movement of the surface forming the object corresponding to the MVF between the first image and the second image.

In addition, when receiving the first information, the user interface screen is displayed for setting the first information, and the second information corresponding to the relationship between the time and the amount of movement of the object in the first information can be received through the displayed user interface screen. The first information may be generated based on the second information.

In addition, when the tomographic scan is performed while the X-ray generator 106 rotates around the object and projects the X-rays in the direction of the object, the operation 3210 for obtaining a first image and a second image may include operations for obtaining a first partial image and a third partial image, respectively , from the first angular section 2621 and the third angular section 2631, which are included in the first "a" angular section 2611 from the angular section having an angle of 180 + a, cat the second is the angular section in one cycle, and the second partial image and the fourth partial image, respectively, from the second angular section 2622 and the fourth angular section 2632, which are included in the last “a” angular section 2612 of the angular section in one cycle, as illustrated in FIG. . 26. The first information indicating the relationship between time and the magnitude of the movement of the object can be obtained based on the magnitude of the movement between the first partial image and the second partial image and the magnitude of the movement between the third partial image and the fourth partial image. The first angular section and the second angular section have a paired angle relation to each other, and the third angular section and the fourth angular section have a paired angle relation to each other.

In addition, tomographic image reconstruction method 3200 may also include, prior to operation 3210, operations for displaying a medical image and selecting an ROI from a medical image (not shown). Operation 3210 may include the steps of extracting a surface line included in the ROI, obtaining a viewing angle corresponding to the extracted surface line, setting a first angular section and a second angular section according to the viewing angle, and obtaining a first image and a second image, respectively, from the first angular section and second angular section.

In addition, the method 3200 reconstruction of the tomographic image may also include the operation of displaying a user interface screen containing a menu for setting a target time (not shown).

The target image corresponding to the target time between the first time and the second time is reconstructed based on the first information obtained in operation 3220 (operation 3230). Operation 3230 can be performed by reconstructing 720 images of the tomographic apparatus 700. In detail, the target image can be obtained by correcting the motion based on the magnitude of the movement of the object at the target time, based on the first information.

In addition, in the reconstructed target image, the degree of correction of the motion of an object included in the target image can be changed in accordance with the target time.

In addition, in the target image, when the target time corresponds to the average angle between the first angular section and the second angular section, the correction of the movement of the object can be improved compared to the correction of the movement of the object when the target time does not correspond to the average angle.

FIG. 33 is a flowchart for explaining a tomographic image reconstruction method 3300 according to another embodiment of the present invention. The operations of the steps included in the tomographic image reconstruction method 3300 according to the present embodiment coincide with the operations of the elements included in each of the tomographic apparatuses 600 and 700 according to the embodiments of the present invention described with respect to FIG. 1-31. Accordingly, in the description of the tomographic image reconstruction method 3300, the redundant descriptions of FIG. 1-31 are omitted.

Turning to FIG. 33; in a tomographic image reconstruction method 3300 according to the present embodiment, a tomographic scan is performed on a moving object (operation 3310). In detail, a first image and a second image are obtained, which are partial images corresponding to the first time and the second time, respectively, and indicating the same parts of the surfaces forming the object. In detail, the first image and the second image are obtained using data obtained in each of their first partial angular section corresponding to the first time, and the second angular section corresponding to the second time and opposite the first angular section, by performing tomographic scanning with rotation in the angular section less than than one revolution around the object. Operation 3310 may be performed by the receiver 710 of the data of the tomographic apparatus 700.

The first information indicating the movement of the object is obtained by using the first image and the second image obtained in operation 3310 (operation 3320). Operation 3320 may be performed by the receiver 710 of the data of the tomographic apparatus 700. The first information may indicate the relationship between time and the magnitude of the movement of the surface forming the object corresponding to the MVF between the first image and the second image.

The corresponding target image is reconstructed based on the first information obtained in operation 3320 (operation 3330). In detail, the target image can be reconstructed by performing the motion correction described in relation to FIG. 19A-24. Operation 3330 may be performed by an image reconstructor 720 of a tomographic apparatus 700.

FIG. 34A is a reconstructed target image generated by a conventional CT system. Turning to FIG. 34A; reconstructed target image 3410 reconstructed by a conventional CT system (not shown) containing an X-ray detector having 128 detectors, provided that the rotation time is 300 ms and the heart rate is 70 beats / min.

Turning to FIG. 34A; as shown in region 3420, motion blur occurs in the reconstructed target image 3410. Accordingly, the coronary artery of the heart in the reconstructed target image 3410 is not clearly shown.

FIG. 34B is a reconstructed target image obtained by a tomographic apparatus according to exemplary embodiments of the present invention.

Turning to FIG. 34B; the reconstructed target image 3450 is reconstructed provided that the X-ray detector has 128 detectors, the rotation time is 300 ms, and the heart rate is 70 beats / min. Turning to FIG. 34B; as shown in region 3460, motion correction is efficiently performed in exemplary embodiments of the present invention, and therefore, the coronary artery of the heart in the reconstructed target image 410 is clearly shown.

As described above, in a tomographic apparatus according to the present invention and a method for reconstructing its tomographic image, an image with reduced motion artifacts can be reconstructed using the initial data obtained by rotation through the angular section per revolution, that is, the angular section corresponding to the angle 180 + additional angle . Accordingly, compared with the amount of data necessary for motion correction according to the prior art, the amount of data for reconstructing the motion-corrected image can be reduced to the amount of data corresponding to the angular section having an angle of 180 + the angle of the fan beam, and the time for receiving and accumulating data can be reduced. Accordingly, the amount of x-ray radiation that the patient is exposed to can be reduced.

In addition, in the tomographic apparatus according to the present invention and the method for reconstructing its tomographic image as described above, the target image is reconstructed by obtaining information about the movement of the object through the first and second images having high temporal resolution, as a result of which the state of movement of the object can be accurately is reflected, and a target image having a high temporal resolution can be reconstructed. In addition, since motion correction is efficiently performed on a surface that is displayed using projection data obtained in the initial angular section and the final angular section in the angular section in one cycle, where the fuzziness is most strongly generated, the target image having a high temporal resolution can be reconstructed. . Accordingly, an image with reduced motion artifacts can be reconstructed.

In addition, other embodiments of the present invention may also be implemented through a computer-readable code / instructions in / on a storage medium, for example, a computer-readable storage medium, for controlling at least one processing element for implementing any of the above embodiments. The storage medium may correspond to any medium / media capable of storing and / or transmitting a machine-readable code.

Machine-readable code can be written / transferred to a storage medium in a variety of ways, while examples of storage media include recording media such as magnetic storage devices (e.g., ROMs, floppy disks, hard drives, etc.) and optical storage media ( e.g. CDROM or DVD), and data transmission media, such as Internet media.

It should be understood that the exemplary embodiments described in the present disclosure should be considered only in a descriptive sense and not for purposes of limitation. Descriptions of characteristics or aspects in each embodiment should generally be considered as available for other similar characteristics or aspects in other embodiments.

While one or more embodiments of the present invention have been described in relation to the figures, those skilled in the art will understand that various changes in form and detail can be made without departing from the form and scope of the present invention, as defined in the following formula inventions.

Claims (26)

1. Tomographic apparatus containing one or more processors that: receive partial images of the object, which are used to obtain the first information indicating the magnitude of the movement of the object, and include the first image obtained at first by using data obtained in the first angular section, which has an angle less than 180 ° and which includes the first time and a second image obtained at a second time by using data obtained in a second angular section opposite the first angular section, which has an angle of less than 180 ° and into which key of the second time, wherein the second angular section does not overlap with the first angled section; receive first information indicating the magnitude of the movement of the object by using the first image and the second image and reconstructing the target image of the object at the target time, which is one of the times between the first time and the second time and is included in an angular section different from the first and second angular sections based on the first information. 2. The tomographic apparatus according to claim 1, wherein the first information is obtained by comparing only the first image and the second image. 3. The tomographic apparatus according to claim 1, wherein the object depicted in the first image and the object depicted in the second image differ from each other in at least one of a size, position and shape. 4. The tomographic apparatus according to claim 1, wherein the times are selected between the first time and the second time, which are different from each other, and the degree of correction of the movement of the object in the target image varies in response to the fact that the target time is selected corresponding to the mentioned time points. 5. The tomographic apparatus according to claim 1, wherein the target time is selected corresponding to the average angle between the first angular section and the second angular section, and in the target image, the correction of the movement of the object is improved in response to the fact that the target time is selected corresponding to the average angle, compared with the correction of the movement of the object when the target time does not correspond to the average angle. 6. The tomographic apparatus according to claim 1, the first information indicating the magnitude of the movement of the surface forming the object. 7. The tomographic apparatus according to claim 1, wherein in the first information, the values of the moments of time and the magnitude of the surface motion indicated as the field of the motion vector between the first and second images have a linear relationship. 8. The tomographic apparatus according to claim 1, wherein said one or more processors are configured to obtain a first image and a second image by using the source data obtained by performing a tomographic scan in cross section for one cycle, which is less than one 360 ° revolution, but the first angular section and the second angular section are, respectively, the initial section and the final section of the section in one cycle. 9. The tomographic apparatus according to claim 1, wherein said one or more processors is configured to reconstruct a target image by using fragments of projection data corresponding to projections, which are the initial data obtained by performing tomographic scanning by rotating the gantry rotary frame by less than one revolution 360 °. 10. The tomographic apparatus according to claim 1, wherein the first information contains information about the surface movements of the object in all directions. 11. Tomographic apparatus according to claim 1, further comprising: a display device configured to display a user interface (UI) configured to receive information indicating a relationship between time and an amount of movement of an object as first information, moreover, the aforementioned one or more processors are configured to obtain first information based on information indicating the relationship between time and the magnitude of the movement of the object. 12. The tomographic apparatus according to claim 1, wherein said one or more processors is configured to obtain projection data corresponding to a section having an angle equal to the sum of 180 ° and an additional angle, and the additional angle is from about 30 ° to about 70 °. 13. The tomographic apparatus according to claim 1, further comprising a display device configured to display a user interface screen containing a menu for setting a target time. 14. A method for reconstructing a tomographic image, comprising: obtaining partial images of the object, which are used to obtain first information indicating the magnitude of the movement of the object, and include the first image obtained at first by using data obtained in the first angular section, which has an angle less than 180 ° and which includes the first time , and a second image obtained at a second time by using data obtained in a second angular section opposite the first angular section, which has an angle less than 180 ° and in which a second time is obtained, the second angular section not overlapping with the first angular section; obtaining first information indicating the amount of movement of the object at times between the first time and the second time, by using the first image and the second image, and reconstruction of the target image of the object at the target time, which is one of the times between the first time and the second time and is included in an angular section different from the first and second angular sections based on the first information. 15. The method of claim 14, wherein obtaining the first information comprises obtaining first information by comparing only the first image and the second image.

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