KR101610142B1 - Apparatus and method for computed tomography - Google Patents

Abstract

The present invention relates to a computer tomography apparatus and method, and more particularly, to a computer tomography apparatus and method, which comprises a detector comprising a plurality of detection sensors arranged in a circle around a scan region in which a scan object can be placed, provided with a fixed shape and detecting a scan beam; And a plurality of sources arranged to surround the scan area and spaced apart from each other, the scan source generating a scan beam for a computer tomography in a scan area by alternately rotating around the scan area.

Description

[0001] APPARATUS AND METHOD FOR COMPUTED TOMOGRAPHY [0002]

The present invention relates to a computer tomography apparatus and method, and more particularly, to a gantry system for a computer tomography.

Generally, a computed tomography (CT) apparatus is an imaging apparatus that displays a tomogram of a human body. The X-ray transmitted through the human body at various angles is measured by a computer, reconstructs the absorption value of the human body, Is a tomographic imaging device.

1 is a schematic view of a conventional computerized tomography apparatus. 1, a computed tomography apparatus rotates a gantry with a single x-ray source 12 and a weighted x-ray detector 11 as shown in the direction of the arrows, A sinogram is generated through scanning to scan the X-rays.

It is important to shorten the scan time, that is, the time required for one rotation of the gantry in order to reduce the defects of the CT image due to the motion of the scan object such as the human body and improve the quality of the CT image. The CT technique has been continuously developed to shorten the acquisition time of the image, and the improvement of the rotation speed of the CT gantry has contributed to the shortening of the acquisition time of the image.

However, the CT gantry structure, which has been commercialized all over the world, has reached a limit of about 0.3 second due to the weight of the basic gantry, and further shortening of the scan time is regarded as a technical difficulty.

Provided is a computer tomography apparatus and method capable of shortening a scan time for a computer tomography and improving the quality of a CT image by reducing image defects due to motion of a scan object such as a human body .

Another object of the present invention is to provide a computerized tomography apparatus and method for scanning a scan beam for a computer tomography at an accurate data acquisition position.

The problems to be solved by the present invention are not limited to the above-mentioned problems. Other technical subjects not mentioned will be apparent to those skilled in the art from the description below.

According to an aspect of the present invention, there is provided a computer tomography apparatus including: a detector including a plurality of detection sensors arranged in a circle around a scan region in which a scan object can be placed, provided with a fixed shape and detecting a scan beam; And a plurality of sources arranged to surround the scan area and spaced apart from each other and generating a scan beam for a scan for computer tomography alternately while rotating around the scan area as a scan area.

Wherein each of the plurality of sources includes: a scan beam generator for generating a scan beam continuously; And a scan beam generator for selectively blocking the scan beam generated from the scan beam generator such that the scan beams are alternately generated from the plurality of sources to a scan area, And may include a beam breaker.

While one of the plurality of beam breakers opens the scan beam generated from the corresponding scan beam generator, the other beam breaker may block the scan beam generated from the corresponding other scan beam generator.

The plurality of sources may be spaced apart at regular intervals along the radius of rotation.

Each of the plurality of sources may be disposed in an area that is not interfered by the scan beam generated from the other source.

(N is the number of sources) sources are located at different data acquisition positions (N-1, N-1, N-1, (K is 1, 2, ..., N-1, m is the number of data acquisition positions)

The computer tomography apparatus may further include a driving unit for rotating the plurality of sources about the scan area.

The computerized tomography apparatus may further include a determination unit that determines whether the plurality of sources are rotated by 360 ° / N (N is the number of sources).

The computer tomography apparatus may further include an image reconstruction unit that generates a tomographic image of a scan target using the data obtained while the plurality of sources rotate 360 ° / N (N is the number of sources).

According to another aspect of the present invention, there is provided a computer readable medium storing a computer program for causing a computer to perform a method of generating a scan beam for a computer tomography in a scan region by alternately rotating around a scan region, A plurality of sources; A circular detector formed of an array of a plurality of detection sensors which are generated from the plurality of sources and detect a scan beam transmitted through the object to be scanned; And a driving unit for rotationally driving the plurality of sources around a scan region.

The computer tomography gantry system further comprises a determination unit that determines whether the plurality of sources have rotated by 360 ° / N (N is the number of sources), and the driver is configured to determine whether the plurality of sources is 360 ° / N , The rotation driving of the plurality of sources can be stopped.

The computer tomography gantry system may further include an image restoration unit that generates a tomographic image using data obtained while the plurality of sources rotate 360 ° / N (N is the number of sources).

According to another aspect of the present invention, there is provided a method of generating a scan beam, comprising the steps of: generating a scan beam as a scan target by alternately rotating a plurality of sources arranged around the scan target, ; And a step of scanning a scan beam which is generated by alternately generating a plurality of detectors arranged in an array of a plurality of detection sensors for detecting scan beams, the scan beams being transmitted through the scan targets, A computer tomography method is provided.

The step of generating the scan beam may include generating a scan beam from the scan beam generator such that a plurality of beam breakers provided on the path of the scan beam correspond to the plurality of sources one by one, And selectively blocking the generated scan beam.

The computed tomography method may further comprise determining whether the plurality of sources has rotated by 360 ° / N (N is the number of sources).

The computerized tomography method may further include generating a tomographic image of the scan target using data obtained while the plurality of sources rotate by 360 ° / N (N is the number of sources).

According to the embodiment of the present invention, it is possible to shorten a scan time for a CT and to improve image quality of a CT image by reducing image defects due to motion of a scan object such as a human body.

In addition, according to the embodiment of the present invention, it is possible to improve the quality of a CT image by scanning a scan beam for computed tomography at an accurate data acquisition position.

The effects of the present invention are not limited to the effects described above. Unless stated, the effects will be apparent to those skilled in the art from the description and the accompanying drawings.

1 is a schematic view of a conventional computerized tomography apparatus.
2 is a perspective view showing a computer tomography apparatus according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view schematically showing a cross section taken along the line A-A 'of the computer tomography apparatus shown in FIG. 2, showing a computer tomography gantry system according to an embodiment of the present invention.
FIG. 4 is a side view schematically showing a plurality of sources and drivers constituting a computer tomography gantry system according to an embodiment of the present invention.
5 to 7 are views for explaining the operation of a computer tomography gantry system according to an embodiment of the present invention.
8 is a view for explaining a computer tomography method according to an embodiment of the present invention.
9A to 9B are schematic views showing a beam breaker constituting a computer tomography gantry system according to an embodiment of the present invention.

Other advantages and features of the present invention and methods of achieving them will be apparent by referring to the embodiments described hereinafter in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and the present invention is only defined by the scope of the claims. Although not defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly accepted by the generic art in the prior art to which this invention belongs. A general description of known configurations may be omitted so as not to obscure the gist of the present invention. In the drawings of the present invention, the same reference numerals are used as many as possible for the same or corresponding configurations.

2 is a perspective view showing a computer tomography apparatus 10 according to an embodiment of the present invention. 2, a computer tomography apparatus 10 according to an embodiment of the present invention includes a gantry system 100 for computed tomography (CT) to scan an x-ray scan beam at various angles And then reconstructing the image with a computer to image the shape of the cross section of the inside of the human body.

3 is a cross-sectional view schematically showing a cross section taken along the line A-A 'of the computer tomography apparatus 10 shown in Fig. 2, which is a view showing a computer tomography gantry system 100 according to an embodiment of the present invention to be. 2 to 3, a CT gantry system 100 according to an embodiment of the present invention includes a detector 110, a plurality of sources 121, 122, And beam blockers 131, 132, and 133.

The detector 110 includes an array of a plurality of detection sensors that are generated from the plurality of sources 121, 122, and 123 and detect a scan beam, for example, a scan beam transmitted through the human body 20. The detector 110 may be circular in shape around a scan region where the human body 20 is located, and may be stationary in a non-rotating state. Therefore, the rotational speed of the gantry system can be increased by the fixed detector 110 provided not to rotate.

The detector 110 may be located outside the radius of rotation of the plurality of sources 121, 122, The detector 110 may be provided as an array of a plurality of detection sensors for detecting scanned scan beams for computed tomography, for example, X-rays. The detection sensor can be composed of, for example, a scintillation detector using X-ray emission, a semiconductor radiation detector, a solid state type detector, a photon counting detector, or various other types of detectors .

The plurality of sources 121, 122, and 123 are spaced apart from one another along the radius of rotation surrounding the scan area where the human body 20 is located. The plurality of sources 121, 122, and 123 may scan, for example, an X-ray scan beam at various angles toward the human body 20 for computer tomography. The plurality of sources 121, 122, and 123 are located in the cylindrical detector 110 and alternate with each other around the scan area to generate a scan beam as a scan area. In FIG. 3, the number of sources 121, 122 and 123 is shown as three, but this is only exemplary and the number of sources 121, 122, and 123 may be variously modified.

Each of the plurality of sources 121, 122 and 123 includes scan beam generators 121a, 122a and 123a for generating a scan beam continuously and a beam 122a for selectively blocking a scan beam generated from the scan beam generators 121a, And may include circuit breakers (131, 132, 133). The beam breakers 131, 132 and 133 are provided on the path of the scan beam in a one-to-one correspondence with the scan beam generators 121a, 122a and 123a to selectively block the scan beams generated from the scan beam generators 121a, 122a and 123a .

That is, while one of the plurality of beam breakers 131, 132, and 133 opens the scan beam generated from the corresponding scan beam generating portion 121a, the other beam breakers 132 and 133 move the corresponding scan beam The scan beams generated from the generating units 122a and 123a can be blocked. By means of the beam breakers 131, 132, 133, scan beams can be generated in the scan region alternately from the plurality of sources 121, 122, 123.

Therefore, since the scan beams generated from the plurality of sources 121, 122, and 123 are not overlapped, image defects due to cross scatter are reduced and the quality of the CT image is improved. Since the plurality of sources 121, 122, 123 are located in the detector 110 and have a relatively small turning radius, the rotational speed of the plurality of sources 121, 122, 123 by the gantry system can be improved. As a result, the scan time for the computer tomography is shortened and the image defect due to the movement of the human body 20 is reduced.

The plurality of sources 121, 122, and 123 may be spaced apart at regular intervals along a virtual circular path. Each of the plurality of sources 121, 122, and 123 may be disposed on an area that is not interfered by the scan beam generated from the other source. The computed tomography apparatus 100 may further include a driving unit (refer to reference numeral 140 in FIG. 4) for rotationally driving the plurality of sources 121, 122 and 123.

4 is a side view schematically showing a plurality of sources 121, 122, 123 and a driving unit 140 constituting a computer tomography gantry system according to an embodiment of the present invention. Referring to FIG. 4, the driving unit 140 is provided for rotationally driving the plurality of sources 121, 122, and 123. The driving unit 140 includes rotary frames 141 and 142 for supporting the plurality of sources 121, 122 and 123 by the support members 143 and a driving motor 144 for rotating the rotary frames 141 and 142.

The interval between the first rotating frame 141 and the second rotating frame 142 can be set so as not to block the scanned scanning beam from the plurality of sources 121, The plurality of sources 121, 122 and 123 can be fixed to the rotary frames 141 and 142 at an angle of approximately 360 ° / N (N is the number of sources) by the support 143. The driving unit 140 rotates the plurality of sources 121, 122 and 123 and stops the rotation of the plurality of sources 121, 122 and 123 when the plurality of sources 121, 122 and 123 rotate by 360 ° / N .

5 to 7 are views for explaining the operation of a computer tomography gantry system according to an embodiment of the present invention. FIG. 5 shows a state in which the scan beam is blocked at the second and third sources 122 and 123 while the first source 121 scans the scan beam for the computer tomography at the data acquisition position toward the human body 20 at the first time point. . 6 shows that at a second time point the scan beam is blocked at the first and third sources 121 and 123 while the second source 122 scans the scan beam at the data acquisition position. FIG. 7 shows that at a third time point, the third source 123 intercepts the scan beam at the first and second sources 121 and 122 while scanning the scan beam at the data acquisition position.

In Figures 5-7, the data acquisition locations 124 are indicated by dashed lines. In the example of FIGS. 5-7, there are 15 data acquisition locations 124 shown, but this is illustrative, and the number of data acquisition locations 124 may have various values. The data acquisition positions 124 may be formed at regular intervals around the human body 20 to be scanned.

A plurality of sources 121,122 and 123 may be coupled to any one of the sources 121,122 and 123 so that the plurality of sources 121,122 and 123 rotate and scan the scan beam alternately at different data acquisition positions 124 (N is the number of sources) sources, e.g., the second and third sources 122 and 123, at the moment when the scan beam is scanned into the scan area at the predetermined data acquisition position 124, Can be arranged to have an offset from 2? K / Nm (where k is 1, 2, ... N-1, m is the number of data acquisition positions) from one of the positions.

As shown in FIGS. 5 to 7, the case where the number of sources 121, 122, and 123 is three and the number of data acquisition positions is 15 will be described as an example. 5 to 7, the beam breaker not shown in the shaded state is in the open state, and the shaded beam circuit breaker is in the cut-off state. 5 through 7, it can be seen that only one of the beam breakers 131, 132 and 133 is open at any time and all other remaining beam breakers are blocked.

5, at a first point in time, the first source 121 is located at a predetermined data acquisition position and irradiates a scan beam for a computed tomography scan to a scan area, (2π / 45) from the other data acquisition positions, and the third source 123 is arranged to have an offset by 16 ° (4π / 45) from another data acquisition position. At this time, the scan beams are generated in the scan beam generators of the second and third sources 122 and 123, but they are blocked by the second and third beam breakers 132 and 133.

Next, referring to Fig. 6, at a second time point when the gantry system rotates and the first to third sources 121, 122, 123 are rotated by 8 degrees, the second source 121 reaches the data acquisition position, The scan beam is scanned into the scan area. At that moment the third source 123 is arranged to be offset by 8 degrees (2 pi / 45) from the other data acquisition positions and the first source 121 is arranged to be offset by 16 degrees (4 pi / 45) from another data acquisition position Offset. At this time, the scan beams are generated in the scan beam generators of the first and third sources 121 and 123, but are blocked by the first and third beam breakers 131 and 133.

7, at a third time point at which the gantry system further rotates and the first to third sources 121, 122 and 123 are further rotated by 8 degrees, the third source 123 reaches the data acquisition position , Then the scan beam is scanned into the scan area. At that moment the first source 121 is arranged to be offset by 8 degrees (2 pi / 45) from the other data acquisition positions and the second source 122 is arranged to be offset by 16 degrees (4 pi / 45) from another data acquisition position Offset. At this time, the scan beams are generated in the scan beam generators of the first and second sources 121 and 122, but are blocked by the first and second beam breakers 131 and 132.

While repeating this process, the plurality of sources 121, 122, and 123 alternately scan the scan beam at the data acquisition position and acquire and collect projection data, i.e., a sinogram, at each scan of the scan beam . The computer tomography gantry system 100 includes a determination unit (not shown) for determining whether a plurality of sources 121, 122 and 123 have rotated by 360 ° / N (N is the number of sources) and a plurality of sources 121, 122, (Not shown) for generating a tomographic image using data acquired during the rotation of the subject (N is the number of sources).

According to the embodiment of the present invention, at the moment when a specific source irradiates a scan beam to a scan area at a predetermined measurement position (data acquisition position), the remaining source is 2? K / Nm , N-1, and m are the number of data acquisition positions), accurate scanning can be performed at all accurate measurement positions, and the quality of the CT image can be improved have.

8 is a view for explaining a computer tomography method according to an embodiment of the present invention. Referring to FIG. 8, while the CT gantry system is being driven, the first to third sources 121, 122 and 123 alternately open the beam interrupters 131, 132 and 133 at the data acquisition positions to scan the human body 20 Through this process, projection data is acquired and stored (S81 to S86).

When the plurality of sources 121, 122, and 123 rotate by 360 ° / N (N is the number of sources), the driving of the CT gantry system is stopped (S87), and while the plurality of sources 121, And the CT image is reconstructed by back projection using the projection data (S88). According to the embodiment of the present invention, since the scan is completed only by rotating the CT gantry system by 360 ° / N (N is the number of sources) without rotating the scan gantry system by 360 °, the scan time (CT scan time) .

In the case of a conventional CT gantry system, if the source (e.g., an x-ray source) was able to acquire all view data only when the source All of the view data can be obtained even if the three sources 121, 122, and 123 are turned only by 120 degrees corresponding to 1/3. Thus, even if the gantry rotation speed that has reached the limit point is maintained, the scan time can be shortened to 1/3 level and the scan speed can be tripled. This is a corresponding effect (about 0.1 second) that the rotation speed (about 0.3 seconds) of the gantry which has already reached the limit point is tripled.

According to the embodiment of the present invention, when N sources are used, the scan speed is dramatically improved to N times, and the scan time can be shortened. According to the embodiment of the present invention, since the detector during rotation of the CT gantry system does not need to rotate, the weight of the rotating structure in the CT gantry system is reduced, thereby also improving the rotation speed of the source do.

Therefore, the defects of the CT image due to the movement of the scan object such as the human body are reduced, and the quality of the CT image is improved. According to the embodiment of the present invention, the influence of the human body motion is reduced particularly in cardiac CT and pediatric CT imaging. In addition, according to the embodiment of the present invention, temporal resolution is increased to improve the quality of the image.

The plurality of sources 121, 122, and 123 sequentially scan the scan beam. In other words, according to the embodiment of the present invention, due to the cross scattering between the scan beams of the plurality of sources 121, 122, 123, the scan beams are alternately generated without being duplicated from the plurality of sources 121, There is no problem that the quality is deteriorated. A CT system according to an embodiment of the present invention implements a spectral CT system that provides images with high material resolution by obtaining data on a patient using a source for scanning X-rays of different energy bands .

9A and 9B are schematic views of a beam breaker 130 constituting a computer tomography gantry system 100 according to an embodiment of the present invention. 9A shows a state in which the beam breaker 130 is closed. At this time, the scan beam generated from the scan beam generator of the source is blocked without being scanned into the scan area. 9B shows a state in which the beam breaker 130 is opened. At this time, the scan beam generated from the scan beam generator is not blocked but is scanned into the scan area.

According to the embodiment of the present invention, the scan beam can be physically turned on / off via the beam interrupter 130 while the scan beam such as X-ray is continuously generated from the scan beam generator . The beam breaker 130 may be provided, for example, with a mechanism such as a camera shutter, which provides a much shorter period (thousands or more per second) than controlling the pulse sequence of the scan beam generator And the on / off state of the scan beam (X-ray) generated from the scan beam generating unit can be controlled.

It is to be understood that the above-described embodiments are provided to facilitate understanding of the present invention, and do not limit the scope of the present invention, and it is to be understood that various modifications are possible within the scope of the present invention. It is to be understood that the technical scope of the present invention should be determined by the technical idea of the claims and the technical scope of protection of the present invention is not limited to the literary description of the claims, To the invention of the invention.

10: Computed tomography apparatus
20: human body
100: Computerized tomography gantry system
110: detector
121, 122,
121a, 122a, and 123a:
130, 131, 132, 133:
140:

Claims (19)

A detector comprising a plurality of detection sensors arranged in a circle around a scan area where a scan object can be placed and provided as a fixed type and detecting a scan beam; And
And a plurality of sources arranged to surround the scan region and spaced apart from each other and generating a scan beam for scanning a computer tomographic scan in a scan region by alternately rotating around the scan region,
(N is the number of sources) sources are located at different data acquisition positions (N-1, N-1, N-1, (K is an integer of 1, 2, ..., N-1, m is the number of data acquisition positions) from one of the plurality of data acquisition positions. The method according to claim 1,
Wherein each of the plurality of sources comprises:
A scan beam generator for continuously generating scan beams; And
A scan beam generator for generating a scan beam in response to the scan beam generated by the scan beam generator; A computer tomography apparatus comprising a circuit breaker. 3. The method of claim 2,
Wherein one of the plurality of beam breakers opens a scan beam generated from a corresponding scan beam generator while the other beam breaker blocks a scan beam generated from another corresponding scan beam generator, Device. The method according to claim 1,
Wherein the plurality of sources are spaced apart at regular intervals along a turning radius. The method according to claim 1,
Each of the plurality of sources being disposed in an area that is not interfered by a scan beam originating from another source. delete The method according to claim 1,
Further comprising a driving section for rotatingly driving the plurality of sources around a scan region. 8. The method of claim 7,
Further comprising a determination unit that determines whether the plurality of sources have rotated by 360 占 N (N is the number of sources). 8. The method of claim 7,
Further comprising an image reconstruction unit that generates a tomographic image of the object to be scanned using the data acquired while the plurality of sources rotate 360 ° / N (N is the number of sources). A plurality of sources arranged to be spaced apart from each other around a scan region in which the scan targets can be arranged and generate a scan beam for a CT scan alternately while rotating around the scan region;
A detector formed of an array of a plurality of detection sensors alternately generated from the plurality of sources to detect a scan beam transmitted through a scan target; And
And a driving unit for rotationally driving the plurality of sources around a scan region,
(N is the number of sources) sources are located at different data acquisition positions (N-1, N-1, N-1, (K is 1, 2, ..., N-1, m is the number of data acquisition positions) from one of the two angular velocity gates. 11. The method of claim 10,
Wherein each of the plurality of sources comprises:
A scan beam generator for continuously generating scan beams; And
A scan beam generator for generating a scan beam in response to the scan beam generated by the scan beam generator; A computer tomography gantry system comprising a breaker. 12. The method of claim 11,
Wherein one of the plurality of beam breakers opens a scan beam generated from a corresponding scan beam generator while the other beam breaker blocks a scan beam generated from another corresponding scan beam generator, Gantry system. delete 11. The method of claim 10,
Further comprising: a determination unit that determines whether the plurality of sources has rotated by 360 ° / N (N is the number of sources). 15. The method of claim 14,
Wherein the driving unit stops rotation driving of the plurality of sources when the plurality of sources rotate by 360 占 N (N is the number of sources). A plurality of sources arranged to be spaced apart from each other around a scan object including an animal other than a human are alternately rotated around a scan object to generate a scan beam as a scan object; And
A step of scanning a scan beam transmitted through the scan object, the scan beam being generated from the plurality of sources alternately from a plurality of sources, the detector comprising a plurality of detection sensors arranged in a circle around the scan target, In addition,
(N is the number of sources) sources are located at different data acquisition positions (N-1, N-1, N-1, (K is 1, 2, ..., N-1, m is the number of data acquisition positions) from one of the two angles. 17. The method of claim 16,
The step of generating the scan beam may include generating a scan beam from the scan beam generator such that a plurality of beam breakers provided on the path of the scan beam correspond to the plurality of sources one by one, And selectively blocking the generated scan beam. 17. The method of claim 16,
Further comprising determining whether said plurality of sources has rotated by 360 ° / N (N is the number of sources). 19. The method of claim 18,
Further comprising generating a tomographic image for a scan object using data obtained while the plurality of sources are rotated by 360 ° / N (N is the number of sources).

Images