KR20140000573A - Apparatus and method for obtaining ct image using correction phantom - Google Patents

Abstract

The present invention relates to an apparatus and a method for obtaining a CT image. Particularly, the present invention relates to an apparatus and a method for obtaining a CT image capable of reducing production costs and objectively correcting a beam hardening phenomenon by using a correction phantom. The present invention is to provide an apparatus for obtaining a CT image. The apparatus for obtaining a CT image includes an object CT-photographed; a correction phantom photographed and arranged near the object; a photographing part detecting a X-ray penetrating the phantom and the object; and a correction part receiving CT data from the photographing part, obtaining beam hardening information by using the phantom data obtained from the correction phantom among the received data, and correcting the beam hardening artifact of the object data obtained from the object.

Description

Apparatus and method for obtaining CT image using correction phantom}

The present invention relates to a CT image acquisition device and an acquisition method, and in particular, by correcting the beam hardening phenomenon using a correction phantom, it is possible to objectively determine the degree of correction, CT image acquisition device that can reduce the unit cost of the product and It relates to the acquisition method.

Computed Tomography (CT) is a test that obtains the cross-sectional image of a subject using X-rays and a computer, and transmits X-rays of narrow beams generated by the X-ray apparatus while rotating them at various angles. By reconstructing a dimensional cross-sectional image or a three-dimensional image, there is an advantage that the change of the living body (lesion) caused by the structure and the disease can be more clearly identified than the simple X-ray imaging.

However, beam-hardening occurs during CT scanning of bones, metals, etc., which are denser than normal tissues present in the body. This is caused by assuming that each photon energy in the beam is the same monochromatic X-ray in the image diagnosis apparatus using X-rays including CT, but in fact, X-rays are multicolored.

In other words, when X-rays penetrate the subject, weak strands of energy are absorbed, and strong lines of energy are transmitted through a portion of the object, which is not actually present in the body but appears to be present in the image. Appears in.

In particular, the hardening of the beam occurs when the metal implants inserted into the skull, the teeth and the body reach a complex structure.

As a method for correcting the beam hardening phenomenon, there is a method using dual-energy, a method using a mathematical model, and the like. In the case of the method using the double energy, the CT equipment itself needs to be replaced, and two X-ray generators and a detection device are required, which causes a high cost.

On the other hand, the method using a mathematical model has to change the parameters according to the volume and structure of the material, such as bone, metal, there is a problem that the effect varies depending on the parameter.

In addition, doctors or radiologists without skilled knowledge and experience cannot easily determine the appearance of these artifacts in the image, and even if corrected, it is difficult to know how well the corrections are made.

If the beam hardening phenomenon is not corrected, there is a problem in that the CT value of the object depending on the position of the image is distorted by the beam hardening phenomenon. However, such an artifact has not been effectively removed in the actual medical field.

It is proposed to solve the problems of the prior art of the present invention, and an object of the present invention is to provide a CT image acquisition device and a method for acquiring a CT image corrected by the beam hardening phenomenon using a correction phantom. .

The present invention for achieving the above object is a subject to be CT scan; A correction phantom disposed adjacent to the subject and photographed together with the subject; An imaging unit which irradiates X-rays and detects X-rays transmitted through the object and the phantom; And a correction unit configured to receive CT data from the photographing unit, obtain beam hardening correction information using the phantom data obtained from the correction phantom among the received CT data, and correct the beam hardening artifact of the object data obtained from the subject. It provides a CT image acquisition device comprising.

At this time, the photographing unit is an X-ray irradiation unit for irradiating X-rays to the subject and the correction phantom; And an X-ray detection unit irradiated from the X-ray irradiation unit and detecting X-rays transmitted through the object and the correction phantom.

On the other hand, the present invention comprises a photographing step of CT imaging the subject and the correction phantom; A correction step of correcting the beam hardening phenomenon of the subject by receiving a CT data photographed from the X-ray detection unit, obtaining beam hardening correction information from the correction phantom; And a checking and terminating step of checking the correction state of the beam hardening phenomenon and ending the correction when the correction state is equal to or greater than a set value.

At this time, in the photographing step, an X-ray irradiation unit irradiates X-rays to the subject and the correction phantom, and the X-ray detector detects X-rays transmitted through the object and the correction phantom, thereby performing CT imaging.

In the correcting step, the photographed CT data is received, the received CT data is separated into the subject data obtained from the subject and the phantom data obtained from the correction phantom, and the subject data is compared with the phantom data. The presence of the beam hardening artifact and the degree of the artifact appearing in the image from the subject data, and the speed of the subject by referring to the degree of the beam hardening artifact in the image and the beam hardening artifact correction information of the correction phantom known in advance. Generating correction information for the cured artifact, and correcting the beam hardening artifact of the subject data using the correction information.

On the other hand, the CT image acquisition method of the present invention may further include correcting the beam hardening artifact until the set value is higher, if the correction state is less than the set value in the check and end step.

According to the present invention, since the corrected degree can be objectively calculated and the degree of the correction effect can be numerically represented, an objective judgment of the corrected degree is possible without depending on the individual judgment of the reader.

In addition, since the addition of a correction phantom for the beam hardening phenomenon correction to the existing CT device, it is possible to reduce the product cost compared to the conventional correction method.

1 is a conceptual diagram schematically showing an apparatus for obtaining CT images according to an exemplary embodiment of the present invention.
2 is a block diagram showing the configuration of a CT image acquisition apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a method of acquiring a CT image by using a CT image acquisition device according to an exemplary embodiment of the present invention.
4 is a flowchart illustrating a process of correcting by a correction unit according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Here, the embodiments of the present invention are provided to sufficiently convey the technical spirit of the present invention to those skilled in the art, and the present invention is not limited to the embodiments described below, and may be embodied in other forms.

1 is a conceptual diagram schematically showing a CT image acquisition apparatus according to an embodiment of the present invention, Figure 2 is a block diagram showing the configuration of a CT image acquisition apparatus according to an embodiment of the present invention, Figure 3 is an embodiment of the present invention 4 is a flowchart illustrating a method of acquiring a CT image using a CT image acquisition device according to an example, and FIG. 4 is a flowchart illustrating a process of correcting by a correction unit according to an embodiment of the present invention.

1 and 2, a CT image acquisition apparatus according to an embodiment of the present invention includes a subject 10 to be CT photographed, a correction phantom 20 disposed adjacent to the subject 10, and the subject ( 10) and a photographing unit 30 for CT imaging the correction phantom 20.

In this case, the correction phantom 20 is manufactured to have a beam hardening characteristic of the subject to be photographed.

On the other hand, the photographing unit 30 is irradiated from the X-ray irradiation unit 31 and the X-ray irradiation unit 31 for irradiating X-rays to the subject 10 and the correction phantom 20, the subject ( 10) and an X-ray detector 33 for detecting X-rays transmitted through the correction phantom 20.

Hereinafter, in this embodiment, 'shooting' means that the detector 33 detects X-rays transmitted from the X-ray irradiation unit 31 and transmitted through the object 10 and the correction phantom 20. Used to mean.

In addition, the CT image acquisition device according to an embodiment of the present invention is connected to the imaging unit 30, in detail the X-ray detector 33, receives the CT data taken from the X-ray detector 33, The beam hardening correction information is obtained using data (phantom data) obtained from the correction phantom 20 among the received CT data, and the beam hardening artifacts of the data (subject data) obtained from the subject 10 are corrected. The correction unit 40 is included.

That is, the CT image acquisition apparatus according to the embodiment of the present invention is irradiated from the X-ray irradiation unit 31, the X-ray detection unit 33 detects the X-rays transmitted through the subject 10 and the correction phantom 20 When photographing the subject 10 and the correction phantom 20, the correction unit 40 receives CT data photographed from the X-ray detection unit 33, acquires beam hardening correction information, and corrects the beam hardening artifact. It is composed.

Meanwhile, the object 10, the correction phantom 20, and the photographing unit 30 are located in a tubular rotating gantry, and the X-ray irradiation unit 31 moves the rotation center O within the rotating gantry. While rotating to the center, it may be configured to irradiate X-rays to the subject 10 and the correction phantom 20, but is not limited to this configuration.

1 to 4, look at the CT image acquisition method according to an embodiment of the present invention.

First, a photographing step (S10) of CT imaging the subject 10 and the correction phantom 20 is performed.

In detail, the X-ray irradiation unit 31 irradiates X-rays to the object 10 and the correction phantom 20, and the X-ray detection unit 33 penetrates the object 10 and the correction phantom 20. By detecting one X-ray, CT scan of the subject 10 and the correction phantom 20 is performed.

In this case, the correction phantom 20 has similar characteristics to the beam hardening characteristic of the object 10, and the object 10 and the correction phantom 20 are not photographed separately, but are simultaneously photographed.

Next, the correction unit 40 receives CT data photographed from the X-ray detection unit 33, obtains beam curing correction information from the correction phantom 20, and corrects the beam curing phenomenon of the subject 10. A correction step S20 is performed.

In detail, the photographed CT data is received, and the received CT data is separated into data (test data) obtained from the test object 10 and data (phantom data) obtained from the correction phantom 20 (S21). At this time, the position information of the subject 10 previously known and the position information of the correction phantom 20 are used.

Thereafter, the object data and the phantom data are compared to determine whether there is a beam hardening artifact in the object data and the degree of the artifact appearing in the image (S22).

Next, the correction information for the beam hardening artifact of the subject is generated by referring to the degree of the beam hardening artifact in the image and the beam hardening artifact correction information of the correction phantom known in advance (S23).

Next, the beam hardening artifact of the subject data is corrected using the correction information (S24).

In addition to the photographing step (S10) and the correction step (S20) as described above, the confirmation and termination step (S30) of checking the correction state of the beam hardening phenomenon and ending the correction when the correction state is equal to or greater than the set value is performed.

At this time, when the correction state is less than the set value, the beam hardening artifact is corrected until it becomes more than the set value.

When the beam hardening phenomenon is corrected using the phantom as in the present embodiment, it is possible to solve the problem of the determination of the artifact according to the skill of the reader, and the objective determination of the degree of correction is possible.

That is, the corrected image can be checked, and the corrected degree can be converted into a value such as root mean sqaured error (RMS) to numerically indicate the corrected effect, thereby improving the reliability of the reader's image.

In addition, by adding a correction phantom for correcting the beam hardening phenomenon to the existing computerized tomography imaging device, it is possible to make a product more cheaply than the conventional method using the dual energy. And described with reference to the drawings illustrating an acquisition method, the present invention is not limited to the embodiments and drawings described above, without departing from the gist of the invention claimed in the claims, the common knowledge in the art Anyone may have various modifications, and such modifications will fall within the scope of the claims.

10: subject 20: phantom for correction
30: photographing unit 31: X-ray irradiation unit
33: X-ray detection unit 40: Correction unit
O: rotation center

Claims (6)

A subject to be CT scan;
A correction phantom disposed adjacent to the subject and photographed together with the subject;
An imaging unit which irradiates X-rays and detects X-rays transmitted through the object and the phantom; And a correction unit configured to receive CT data from the photographing unit, obtain beam hardening correction information using the phantom data obtained from the correction phantom among the received CT data, and correct the beam hardening artifact of the object data obtained from the subject. CT image acquisition device comprising. The method of claim 1,
The photographing unit comprises: an X-ray irradiation unit for irradiating X-rays to the subject and the correction phantom; And
And an X-ray detector configured to detect X-rays transmitted from the X-ray radiator and transmitted through the subject and the correction phantom. A photographing step of CT imaging the subject and the correction phantom;
A correction step of correcting the beam hardening phenomenon of the subject by receiving a CT data photographed from the X-ray detection unit, obtaining beam hardening correction information from the correction phantom; And
And a checking and ending step of checking the correction state of the beam hardening phenomenon and ending the correction when the correction state is equal to or greater than a set value. The method of claim 3, wherein
And the photographing step comprises CT imaging by X-ray irradiation unit irradiating X-rays to the subject and the correction phantom, and X-ray detector detecting X-rays transmitted through the object and the correction phantom. The method of claim 3, wherein
In the correcting step, the photographed CT data is received, and the received CT data is separated into the subject data obtained from the subject and the phantom data obtained from the correction phantom,
Comparing the subject data and the phantom data to determine the presence or absence of the hardening artifacts in the subject data and the degree to which the artifacts appear in the image,
Generating correction information for the beam hardening artifact of the subject by referring to the degree of the beam hardening artifact in the image and the beam hardening artifact correction information of the correction phantom known in advance;
Compensating the beam hardening artifacts of the subject data using the correction information. The method of claim 3, wherein
And correcting the beam hardening artifact until the correction state is less than or equal to the set value in the checking and terminating step.

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