KR101914522B1 - Cone Beam Computed Tomography System for Correcting Scatter Using Binary Moving Blocker - Google Patents

Abstract

These embodiments match the time of maintaining the state of the strip at the time the beam of radiation is turned on, match the time and delay time of transforming the state of the strip at the time the beam of radiation is turned off, The scattering map for the second projection data obtained by passing the data and the radiation is estimated. Thus, by removing the unnecessary pre-procedure while removing the X-ray scattering phenomenon in the X-ray image with one scan, A cone-beam computed tomography system capable of acquiring a line image is provided.

Description

Technical Field [0001] The present invention relates to a cone beam computed tomography system for correcting scattering using a binary moving beam interrupter,

The technical field to which this embodiment belongs is a cone-beam computed tomography system that corrects scattering using a beam-breaker.

The contents described in this section merely provide background information on the present embodiment and do not constitute the prior art.

Cone Beam Computed Tomography (CBCT) system can acquire images by taking a relatively short amount of radiation and taking a short time, compared with conventional CT scans. However, the CBCT has a problem that the quality of an image deteriorates due to a scattering phenomenon occurring when an X-ray is irradiated on an object (for example, a patient's body). There is a method of using a beam blocker as a method of eliminating the scattering phenomenon of X-rays and improving the quality of the image.

Non-Patent Document 1 improves the image quality by performing two scans. The X-ray image is acquired from the object to be detected without inserting the beam interrupter in one scanning process. In another scanning process, a beam interrupter is inserted to obtain an X-ray image including a shaded region, and a scattered image is obtained from the obtained X-ray image. Finally, the scattered image is removed from the obtained X-ray image without inserting the beam interrupter, thereby obtaining the image from which the scattering phenomenon is eliminated. This method has a problem that the total amount of radiation received by the subject is increased and takes a long time by performing a total of two scans.

Non-Patent Document 2 acquires a scattered image with only one scan. In this method, a scattering image is acquired using a blocking region of a projection by moving a beam breaker having a slit at a constant velocity, and a scattered image is removed in a non-blocking region of the projection to obtain a scattered image. Such a method operates in the full-fan mode, and the detector must be installed horizontally symmetrically to the axis of rotation of the gantry. In order to expand to Half-Fan mode, a preprocessing process is required to grasp the movement of the blocking area and the non-blocking area for each projection, since the blocking area of the detector changes continuously while the gantry rotates . In addition, since the beam breaker continuously moves without a delay time, an image lag occurs in which overexposed data in the blocking area or the non-blocking area is stained with the original image or the scattered image in terms of time, .

Therefore, a CBCT that can operate in the half fan mode and improve the quality of the reconstructed image by effectively removing the scattering phenomenon is needed.

 Zhu L, Xie Y, Wang J and Xing L, 2009, Scatter correction for cone-beam CT in radiation therapy, Medical Physics 36 2258-68.  Ouyang L, Song K and Wang J, 2013, A moving blocker system for cone-beam computed tomography scatter correction, Medical Physics 40 071903.

Embodiments of the present invention provide a method and apparatus for matching a time of maintaining the state of a strip at the time the radiation beam is turned on, matching the time and delay time for converting the state of the strip at the time the radiation beam is turned off, 1 projection data and the second projection data acquired by passing the radiation, it is possible to accurately remove the X-ray scattering phenomenon from the X-ray image in one scan, and eliminate the unnecessary pre-procedure, Ray image of a patient.

Other and further objects, which are not to be described, may be further considered within the scope of the following detailed description and easily deduced from the effects thereof.

According to an aspect of the present invention, there is provided a cone-beam computed tomography system including a body, a gantry connected to the body and configured to be rotatable in at least one direction with respect to the body, A gantry, a radiation head connected to the gantry and configured to irradiate a subject with a radiation beam, a panel connected to the gantry and sensing a radiation beam transmitted through the subject to obtain a plurality of projection data, A beam breaker mounted on the radiation head and including a plurality of strips positioned in a path between the radiation head and the object to block at least a portion of the radiation beam irradiated from the radiation head, Beam Blocker), and a processor (Proce) for generating a reconstructed image by estimating a scattering map of the plurality of projection data The present invention provides a cone-beam computed tomography system including a scepter.

According to another aspect of the present invention, there is provided a cone-beam computed tomography method using a cone-beam CT imaging system, comprising the steps of: irradiating at least a portion of a radiation beam irradiated from the radiation head, Detecting a radiation beam transmitted through the object to obtain a plurality of projection data and estimating a scattering map of the plurality of projection data to generate a reconstructed image The present invention provides a cone-beam computed tomography method.

As described above, according to the embodiments of the present invention, the time for maintaining the state of the strip at the time when the radiation beam is turned on is matched, the time and the delay time for converting the state of the strip at the time when the radiation beam is turned off are matched The first projection data obtained by cutting off the radiation and the second projection data obtained by passing through the radiation are estimated so that unnecessary preliminary procedures can be performed while accurately removing the X-ray scattering phenomenon in the X- Ray image can be obtained by removing the scattering phenomenon more rapidly.

Even if the effects are not expressly mentioned here, the effects described in the following specification which are expected by the technical characteristics of the present invention and their potential effects are handled as described in the specification of the present invention.

1 is a diagram illustrating a cone-beam CT system.
2 is a block diagram illustrating a cone-beam computed tomography system in accordance with an embodiment of the present invention.
FIG. 3 is a view illustrating an operation in which a cone-beam CT system according to an embodiment of the present invention blocks a part of a radiation beam for each second projection.
FIG. 4 is a view showing a second projection data obtained without shielding a beam of radiation from a scattering map of first projection data obtained by shielding a part of the radiation beam for each second projection, according to an embodiment of the present invention. The scattering map of FIG.
5 is a diagram illustrating first projection data, a scattering map, a second projection data, and a scattering correction image acquired by the cone-beam computed tomography system according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating an operation in which a cone-beam CT system according to an embodiment of the present invention blocks a part of a radiation beam for each fifth projection.
FIG. 7 is a graph showing the relationship between the second projection data obtained without shielding the radiation beam from the scattering map of the first projection data obtained by shielding a part of the radiation beam for every fifth projection by the cone- The scattering map of FIG.
FIG. 8 is a diagram illustrating an operation in which a cone-beam CT system according to an embodiment of the present invention blocks a part of a radiation beam for each tenth projection.
FIG. 9 is a view showing a second projection data obtained without shielding a radiation beam from a scattering map of first projection data acquired by blocking a part of a radiation beam for each tenth projection, according to an embodiment of the present invention. The scattering map of FIG.
FIG. 10 is a graph showing the distribution of the first projection data obtained by shielding a part of the radiation beam from the scattering map of the entire first projection data obtained by blocking the radiation beam according to the embodiment of the present invention. And the scattering map is estimated.
11 is a graph illustrating a time and a delay time for converting a strip state in consideration of a time when radiation is turned on and off in a cone-beam CT system according to an embodiment of the present invention.
12 is a diagram illustrating an example of a reconstructed image generated by a cone-beam computed tomography system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Will be described in detail with reference to exemplary drawings.

Cone beam computed tomography system is a device that reconstructs multiple tomographic images at a time in a two-dimensional perspective image obtained by irradiating cone-shaped X-rays. A plurality of horizontal tomographic images can be calculated by only one projection image measurement, so that the three-dimensional structure of the subject can be restored at a high speed.

Referring to FIG. 1, a cone-beam CT system includes a gantry 110, a radiation head 120, and a panel detector 130. The gantry 110 rotates 360 degrees about the subject positioned between the radiation head 120 and the panel detector 130. The cone-beam computed tomography system captures and reconstructs two-dimensional images of about 650 images at predetermined angular intervals.

Cone beam computed tomography system can operate in full-fan mode or half-fan mode depending on the size of the field of view (FOV). If the size of the detector does not include the anatomical size of the subject, it operates in half fan mode. In order to minimize the patient dose and to equalize the X-ray intensity, a Bowtie filter made of aluminum or the like is attached in front of the X-ray to acquire an image.

2 is a block diagram illustrating a cone-beam computed tomography system in accordance with an embodiment of the present invention. 2, the cone-beam computed tomography system 200 includes a body 210, a gantry 220, a radiation head 230, a panel detector 240, A beam blocker 250, and a processor 260. Cone beam computed tomography system 200 may omit some of the various components illustrated in FIG. 2 or may additionally include other components. For example, the cone-beam computed tomography system 200 may further include at least one of a radiation state conversion unit 270, a strip-state conversion unit 280, and a pulse generator 290.

The gantry 220 is connected to the main body 210 and is formed to be rotatable in at least one direction with respect to the main body 210. The gantry 220 may further include an inclinometer sensor.

The radiation head 230 is connected to the gantry 220 and irradiates the subject with a radiation beam. The radiation head 230 may include a radiation state transducer 270 that converts a state between a first radiation state in which the radiation beam is turned on and a second radiation state in which the radiation beam is turned off.

The radiation head 230 operates during a scan time to photograph the subject. Here, the scan time includes the radiation on time at which the radiation beam is turned on and the radiation off time at which the radiation beam is turned off.

The panel sensor 240 is connected to the gantry 220 and senses the radiation beam transmitted through the object to obtain a plurality of projection data. The panel detector 240 obtains the first projection data in a first strip state in which a plurality of strips of the beam breaker 250 are closed. The panel detector 240 obtains second projection data in a second strip state in which a plurality of strips of the beam breaker 250 are open.

The beam breaker 250 is mounted to the radiation head 230 or the gantry 220. The beam breaker 250 includes a plurality of strips positioned in the path between the radiation head 230 and the object to block at least a portion of the radiation beam irradiated from the radiation head 230.

The beam breaker 250 includes a lead strip and a blocking portion. The strip may be formed with a plurality of slits spaced at predetermined intervals. The strips and blocking portions may be alternately disposed to block or pass the radiation beam. The beam breaker 250 moves the strip or blocking portion to block a portion of the radiation beam.

The beam breaker 250 may include a strip state transducer 280 that transforms a state between a first strip state in which a plurality of strips are closed to shield radiation and a second strip state in which a plurality of strips are opened to allow radiation to pass therethrough have.

The strip state conversion unit 280 determines whether the gantry 220 moves or stops based on the inclination angle measured by the inclination sensor of the gantry 220, thereby changing the state of the strip or the blocking unit.

The processing unit 260 estimates a scattering map for a plurality of projection data to generate a reconstructed image. The processor 260 estimates a scattering map of the first projection data and the second projection data acquired by the panel detector 240 to generate a reconstructed image.

The processing unit 260 generates a reconstructed image by applying a reconstruction algorithm to a plurality of projection data. The processing unit 260 may be implemented as an ART (Algebraic Reconstruction Technique), a SART (Simultaneous Algebraic Reconstruction Technique), a DART (Directional Algebraic Reconstruction Technique), an Expectation Maximization (EM), a Filtered Backprojection (FBP), a Feldkamp-Davis- It can be used as a reconstruction algorithm such as projection, CS-IR (Compressed Sensing-Based Iterative Reconstruction) and TV (Total Variation) Regularization. FBP is a method of processing the filter first to remove the blurring of the back projection data generated by the back projection method. The conventional back projection method performs filter processing after the addition of the inverse image, while the filter correction back projection method filters the projection image and then performs the reverse projection. FDK reconstructs based on the principle of FBP and processes the operation independently of each pixel.

The processing unit 260 generates the scattered image through interpolation and filtering using the image signal of the middle part of the area where the X-ray is blocked by the beam blocker 250 in the obtained first projection data.

In order to avoid a penumbra effect, the cone-beam CT system 200 includes a beam interrupter 250, a beam interrupter 250, an X- Can be used. The entire scattering image can be generated by interpolating or extrapolating the remaining part using the image signal in the middle part. At this time, a scattering image generated by interpolating or extrapolating using a moving average filter is processed to remove noise.

The cone-beam computed tomography system 200 periodically inserts and removes the beam-breaker 250 in the path between the X-ray source and the subject while the X-ray source rotates the subject at a predetermined rotation speed.

The cone-beam computed tomography system 200 acquires the first projection data at the stage in which the beam interrupter 250 is inserted and acquires the second projection data at the stage in which the beam interrupter 250 is removed.

The cone-beam computed tomography system 200 generates the scattered image through interpolation and filtering using the image signal of the middle part of the area where the X-ray is blocked by the beam-cutter 250 in the obtained first projection data.

The cone-beam computed tomography system 200 generates an average scattered image by summing at least two scattered images generated for the first projection data obtained in the vicinity of the second projection data.

The cone-beam computed tomography system 200 subtracts a predetermined multiple of the average scattering image from the second projection data to generate a scattering-free image.

The cone-beam computed tomography system 200 performs a convolution-based iterative reconstruction (CS-IR) algorithm, a FDK (Feldkamp-Davis-Kress) algorithm, a SART (Simultaneous Algebraic Reconstruction Technique) the total reconstruction algorithm, and the total variation regression algorithm.

Cone beam computed tomography system 200 may further include a pulse generator 290. The pulse generator 290 is connected to the radiation state conversion unit 270 and the strip state conversion unit 280 and generates a control signal having a predetermined pulse width.

Hereinafter, the operation of estimating the scattering map of the second projection data positioned between the two first projection data from the scattering map of the two first projection data will be described with reference to Figs. 3 to 9. Fig.

FIG. 3 is a view illustrating an operation in which a cone-beam CT system according to an embodiment of the present invention blocks a part of a radiation beam for each second projection, FIG. 4 is a cross- The system estimates the scattering map of the second projection data acquired without shielding the radiation beam from the scattering map of the first projection data obtained by blocking a part of the radiation beam for each second projection.

Referring to FIG. 3, the X-ray light source irradiates X-rays while rotating. A BMB (Binary Moving Blocker), that is, a beam breaker blocks part of the X-ray in the path between the X-ray light source and the subject. The first projection data acquired by the panel sensor includes a shaded region and an unshaded region. The shaded area has a stripe pattern. The second projection data acquired by the panel sensor includes a non-shaded area.

Referring to FIG. 4, the processing unit estimates and generates a first scattering map related to the first projection data by using scattering data in a shadow area included in the first projection data. The processor estimates a second scattering map relating to the second projection data using the first scattering maps of the two first projection data adjacent to the second projection data according to the order of the acquired projection data. The scattering map for the second projection data can be calculated using an average of the scattering maps for the two first projection data adjacent to the second projection data. The scattering map is estimated by applying 1-Dimensional Cubic B-Spline interpolation to the v direction. To avoid the Penumbra effect due to the direction of the X-ray beam and the thickness of the strip, exclude the area adjacent to the edge of the strip when estimating the scattering map. The average value of the scattering data existing in a central region of a part (for example, 1/3) of each shading region can be considered as a representative reference point of 1-Dimensional Cubic B-Spline Interpolation. 5A shows the first projection data obtained by inserting the beam interrupter, and FIG. 5B shows the scattering map estimated from the first projection data.

The processor subtracts the second scattering map from the second projection data to generate scatter correction data, and generates a reconstruction image from the scatter correction data using the reconstruction algorithm. 5C shows the second projection data obtained by removing the beam interrupter, and FIG. 5D illustrates the scatter correction image obtained by subtracting the average scattered image.

6 is a view illustrating an operation in which a cone-beam CT imaging system according to an embodiment of the present invention blocks a part of a radiation beam for every fifth projection, FIG. 7 is a view illustrating an operation of cone- The system estimates the scattering map of the second projection data acquired without shielding the radiation beam from the scattering map of the first projection data acquired by blocking a part of the radiation beam for every fifth projection.

FIG. 8 is a view illustrating an operation in which a cone-beam CT system according to an embodiment of the present invention blocks a part of a radiation beam for each tenth projection, FIG. 9 is a cross- The system estimates the scattering map of the second projection data acquired without shielding the radiation beam from the scattering map of the first projection data obtained by blocking a part of the radiation beam for each tenth projection.

The panel detector may successively acquire the second projection data to obtain the first projection data and the second projection data at a ratio of 1 to N (N is a natural number).

The processor may estimate scatter maps for the N second projection data using scatter weights based on the distances from the two first projection data from the scatter maps for the two first projection data adjacent to the N second projection data, can do.

FIG. 10 is a graph showing the distribution of the first projection data obtained by shielding a part of the radiation beam from the scattering map of the entire first projection data obtained by blocking the radiation beam according to the embodiment of the present invention. And the scattering map is estimated.

The processing unit estimates and generates a scattering map for the entire first projection data, and reconstructs a 3D scatter volume using a back projection. The back projection is a method of reversing the values of the projection images obtained in each direction and adding them consecutively. After the summation is completed, the base pixel value is subtracted from the pixel value, which is the lowest value among the entire pixel values, and then divided by the least common multiple value of the pixels to reconstruct the original pixel value.

The processing unit can reproduce the 3D scattering volume and estimate and generate a scattering map for the entire second projection data.

11 is a graph illustrating a time and a delay time for converting a strip state in consideration of a time when radiation is turned on and off in a cone-beam CT system according to an embodiment of the present invention.

The strip state conversion section operates in accordance with the cycle time at which the gantry rotates. Wherein the cycle time includes a strip condition holding time for maintaining the condition of the strip and a strip condition changing time for converting the condition of the strip.

The strip state conversion unit matches the strip state holding time with the radiation on time, and sets the strip state conversion time shorter than the radiation off time. The strip state conversion section includes a delay time between the strip state conversion time and the strip state holding time, and matches the strip state conversion time and the delay time with the radiation off time. The delay time may be divided into a first delay time and a second delay time.

The pulse generator can control by setting the first delay time and the second delay time at the same time interval. The pulse generator can be controlled by setting the strip state holding time and the strip state conversion time at the same time interval.

The strip state conversion section moves or stops the strip or blocking section according to the control signal of the pulse generator. The strip state conversion unit may further include a strip moving unit. The strip moving part may be implemented by an air compressor, a step motor, or a combination thereof. The strip moving unit moves the strip or blocking unit by the control signal of the pulse generator. The strip moving part can change the position of the strip or blocking part or change the gap between the strip and the blocking part.

The normal rotation speed for diagnosis is 360 degrees / min and the number of projections required for scanning is 656. The scan time required to obtain the projection while rotating the gantry at 0.55 degrees can be calculated as 90 ms.

The processor can set the radiation on time to 20 ms, the radiation off time to 70 ms, the strip state hold time to 20 ms, the strip state change time to 20 ms, the first delay time to 25 ms and the second delay time to 25 ms However, the present invention is not limited thereto, and appropriate values may be used according to the design to be implemented.

12 is a diagram illustrating an example of a reconstructed image generated by a cone-beam computed tomography system according to an embodiment of the present invention.

The cone beam computed tomography system was imaged in half fan mode for Catphan 504. The beam breaker includes 10 lead strips having a thickness of 3 mm, and the spacing between the strips is 1.5 mm. A Bowtie filter was attached to the light source. The panel detector was moved 160 mm from the center in the u direction. The number of projections is 656, the size of the projection is 397.3x 298.0 mm ^2, and the projection contains 1024x 768 pixels. The distance between the light source and the detector is 1500 mm, the distance between the light source and the rotation axis is 1000 mm, and the distance between the light source and the beam breaker is 245 mm. The X-ray tube current was 80 mA, the X-ray pulse was 20 ms, and the tube voltage was set to 125 kVp.

12 (a) is a reconstructed image generated by applying the FDK algorithm without using the beam interception method according to the present embodiment, FIG. 12 (b) is a reconstructed image generated by applying the beam blocking method according to the present embodiment, FIG. 12C is a reconstruction image generated by applying the CS-IR algorithm without using the beam blocking method according to the present embodiment, and FIG. 12D is a reconstruction image generated by applying the CS- It is a reconstructed image generated by applying the beam cut-off method according to the example and applying the CS-IR algorithm.

As shown in Fig. 12, according to this embodiment, it is possible to smoothly arrange the noise, to preserve a large-scale feature, and to remove the bowtie ring artifact.

Although the components included in the cone-beam computed tomography system are shown separately in Fig. 2, a plurality of components may be combined with each other to form at least one module. The components are connected to a communication path connecting a software module or a hardware module inside the device and operate organically with each other. These components communicate using one or more communication buses or signal lines.

Cone beam computed tomography systems may be implemented in software, hardware, or a combination thereof in a computing device having hardware components. The computing device includes a communication device such as a communication modem for performing communication with various devices or wired / wireless communication networks, a memory for storing data for executing a program, a microprocessor for executing and calculating a program, Device. ≪ / RTI >

The operations according to the present embodiments may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. A computer-readable medium represents any medium that participates in providing instructions to a processor for execution. The computer readable medium may include program instructions, data files, data structures, or a combination thereof. For example, there may be a magnetic medium, an optical recording medium, a memory, and the like. The computer program may be distributed and distributed on a networked computer system so that computer readable code may be stored and executed in a distributed manner. Functional programs, codes, and code segments for implementing the present embodiment may be easily deduced by programmers of the technical field to which the present embodiment belongs.

The present embodiments are for explaining the technical idea of the present embodiment, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

200: cone beam computerized tomography system
210: main body 220: gantry
230: Radiation head 240: Panel detector
250: beam breaker 260:
270: radiation state conversion unit 280: strip state conversion unit
290: Pulse generator

Claims (20)

In a Cone-Beam Computed Tomography system,
A body;
A gantry connected to the main body and formed to be rotatable in at least one direction with respect to the main body;
A radiation head connected to the gantry and irradiating a subject with a radiation beam;
A panel detector connected to the gantry and sensing a radiation beam transmitted through the object to obtain a plurality of projection data;
A beam blocker mounted on the radiation head and including a plurality of strips positioned in a path between the radiation head and the object to block at least a portion of the radiation beam irradiated from the radiation head; And
And a processor for estimating a scattering map of the plurality of projection data to generate a reconstructed image,
(I) a first radiation state in which the radiation beam is turned on during a radiation on time during which the radiation beam is turned on, and (ii) a second radiation state during which the radiation beam is turned off during a radiation off time during which the radiation beam is turned off And a radiation state converting unit for periodically converting the gantry while rotating,
Wherein the beam breaker comprises: (i) a first strip condition in which the plurality of strips are inserted in a path of travel of the beam of radiation to block a portion of the beam of radiation; and (ii) And a strip state conversion unit for converting the state between the second strip state in which the plurality of strips is removed in the course of the radiation beam during the radiation off time. The method according to claim 1,
Wherein the panel sensor acquires first projection data including a shaded region and a unshaded region having a stripe pattern in the first strip state, and acquires first projection data including a non-shaded region in the second strip state Acquiring second projection data including the first projection data,
Wherein the processor estimates the scattering map related to the first projection data and the second projection data to generate the reconstructed image. delete delete The method according to claim 1,
The strip-
Wherein the cycle time includes a strip condition holding time for maintaining the condition of the strip and a strip condition changing time for changing the condition of the strip, system. 6. The method of claim 5,
The strip-
The strip state change time is set to be shorter than the radiation off time, and the delay time is included between the strip state change time and the strip state hold time, Wherein the conversion time and the delay time are matched to the radiation off time. The method according to claim 6,
Further comprising a pulse generator connected to the radiation state converting unit and the strip state converting unit and generating a control signal having a predetermined pulse width. 8. The method of claim 7,
The delay time is divided into a first delay time and a second delay time,
Wherein the pulse generator sets and controls the first delay time and the second delay time at the same time intervals. 8. The method of claim 7,
Wherein the pulse generator comprises:
Wherein the control unit sets the strip state holding time and the strip state conversion time at the same time intervals. 8. The method of claim 7,
The strip-
Wherein the blocking unit of the strip or the beam breaker is moved or stopped according to the control signal of the pulse generator. 9. The method of claim 8,
Wherein,
The radiation on time is 20 ms, the radiation off time is 70 ms, the strip state holding time is 20 ms, the strip state conversion time is 20 ms, the first delay time is 25 ms, the second delay time is 25 ms Of the cone-beam computed tomography system. 9. The method of claim 8,
Wherein the gantry further comprises an inclinometer sensor,
Wherein the strip state conversion unit determines whether the gantry is moved or stopped based on a tilt angle measured by the tilt sensor, and converts the state of the strip. delete 3. The method of claim 2,
Wherein,
Estimating and generating a first scattering map related to the first projection data by using scattering data in the shade area included in the first projection data, And estimates and generates a second scattering map relating to the second projection data using the first scattering maps related to the two first projection data adjacent to the second projection data. 15. The method of claim 14,
Wherein the scattering map for the second projection data is calculated using an average of scattering maps for two first projection data adjacent to the second projection data. 15. The method of claim 14,
Wherein,
And generating the reconstructed image from the scatter correction data by using the reconstruction algorithm to generate scatter correction data by subtracting the second scattering map from the second projection data to generate scatter correction data, system. 3. The method of claim 2,
Wherein the panel sensor successively acquires the second projection data and obtains the first projection data and the second projection data at a ratio of 1 to N (N is a natural number)
Wherein the processing unit is configured to calculate, from scattering maps of two first projection data adjacent to the N second projection data, a weight sum based on a distance from the two first projection data, And estimates scattering maps of the cone-beam computed tomography system. 3. The method of claim 2,
Wherein,
Estimating and generating a scattering map for the entire first projection data, reconstructing a 3D scatter volume using a back projection, reprojecting the 3D scattering volume, 2 scattering map for the entire projection data is estimated and generated. A cone-beam computed tomography method using a cone-beam computed tomography system,
Rotating a radiation head of the cone-beam computed tomography system, the method comprising: (i) a first radiation state in which the radiation beam is turned on for a radiation on time during which the radiation beam irradiated from the radiation head is turned on, and (ii) Periodically converting a state between a second radiation state in which the radiation beam is turned off for a period of time while the gantry of the cone-beam computed tomography system is rotated;
Blocking at least a portion of the radiation beam irradiated from the radiation head located in a path between the radiation head and the subject of the cone-beam computed tomography system;
Sensing a radiation beam transmitted through the subject and obtaining a plurality of projection data; And
Estimating a scattering map for the plurality of projection data to generate a reconstructed image,
Wherein blocking at least a portion of the beam of radiation includes: (i) a first strip condition in which the plurality of strips are inserted into a path of travel of the beam of radiation to block a portion of the beam of radiation, and (ii) Wherein the plurality of strips are transformed during the radiation off time to a state between a second strip state in which the plurality of strips are removed from the path of travel of the radiation beam. 20. The method of claim 19,
Wherein the obtaining of the plurality of projection data includes obtaining first projection data including a shaded region and a unshaded region having a stripe pattern in the first strip state, Acquiring second projection data including the non-shaded area,
Wherein the reconstructing image generating step estimates the scattering map regarding the first projection data and the second projection data to generate the reconstructed image.

Images